| Zhou, W., M. S. Hurlbert, et al. (2000). "Overexpression of human alpha-synuclein causes dopamine neuron death in rat primary culture and immortalized mesencephalon-derived cells." Brain Res 866(1-2): 33-43.
Parkinson's disease (PD) is a neurodegenerative disorder characterized by the appearance of intracytoplasmic inclusions called Lewy bodies (LB) in dopamine neurons in the substantia nigra and the progressive loss of these neurons. Recently, mutations in the alpha-synuclein gene have been identified in early-onset familial PD, and alpha-synuclein has been shown to be a major component of LB in all patients. Yet, the pathophysiological function of alpha-synuclein remains unknown. In this report, we have investigated the toxic effects of adenovirus-mediated alpha-synuclein overexpression on dopamine neurons in rat primary mesencephalic cultures and in a rat dopaminergic cell line - the large T-antigen immortalized, mesencephalon-derived 1RB3AN27 (N27). Adenovirus-transduced cultures showed high-level expression of alpha-synuclein within the cells. Overexpression of human mutant alpha-synuclein (Ala(53)Thr) selectively induced apoptotic programmed cell death of primary dopamine neurons as well as N27 cells. The mutant protein also potentiated the neurotoxicity of 6-hydroxydopamine (6-OHDA). By contrast, overexpression of wild-type human alpha-synuclein was not directly neurotoxic but did increase cell death after 6-OHDA. Overexpression of wild-type rat alpha-synuclein had no effect on dopamine cell survival or 6-OHDA neurotoxicity. These results indicate that overexpression of human mutant alpha-synuclein directly leads to dopamine neuron death, and overexpression of either human mutant or human wild-type alpha-synuclein renders dopamine neurons more vulnerable to neurotoxic insults.
Zhang, Y., V. L. Dawson, et al. (2000). "Oxidative stress and genetics in the pathogenesis of Parkinson's disease." Neurobiol Dis 7(4): 240-50.
Parkinson's Disease (PD) is the second most common chronic neurodegenerative disease characterized by the progressive loss of dopamine neurons, leading to rigidity, slowness of movement, rest tremor, gait disturbances, and imbalance. Although there is effective symptomatic treatment for PD, there is no proven preventative or regenerative therapy. The etiology of this disorder remains unknown. Recent genetic studies have identified mutations in alpha-synuclein as a rare cause of autosomal dominant familial PD and mutations in parkin as a cause of autosomal recessive familial PD. The more common sporadic form of PD is thought to be due to oxidative stress and derangements in mitochondrial complex I activity. Understanding the mechanism by which familial linked mutations and oxidative stress cause PD has tremendous potential for unraveling the mechanisms of dopamine cell death in PD. In this article, we review recent advances in the understanding of the role of genetics and oxidative stress in the pathogenesis of PD.
Yuasa, T. (2000). "[Therapeutic strategies for Parkinson's disease and guidelines for the 21st century]." Nippon Rinsho 58(10): 1965-7.
Parkinson's disease(PD) is one of the most common neurodegenerative disorders, characterized clinically by resting tremor, rigidity and akinesia. The pathological hallmarks of PD is the loss of neurons of the substantia nigra and the existence of Lewy bodies. Among multifactorial theories of gene-environment interaction supporting the pathogenesis of this disease, recent topics focus on the findings of single gene mutations found in several forms of familial PDs. The mutations of the gene encode the protein alpha-synuclein, UCH-L1 and Parkin located on the chromosomes 4q21-23, 4p and 6p25.2-27 respectively. Molecular pathology and histochemical studies reveal that one of these proteins is closely associated with parts of Lewy bodies, or has the function of the ubiqitin system of protein metabolism. Although the typical PD shows good response to levodopa therapy, its side effects, which arise after 5 to 10 years of treatment, rather narrow the therapeutic window of PD. As a result we must make available various new therapeutic tools in order to prevent disability and get a favourable QOL in the PD patient's life span. The various tools adopted here include surgical treatments, transcraial magnetic stimulation methods, nonconvulsive electric stimulation therapy, and the design of new drugs. In this issue the frontier of PD therapy and research will be reviewed and new promising insights and guidelines for the current century will be discussed.
Yang, F., K. Ueda, et al. (2000). "Plaque-associated alpha-synuclein (NACP) pathology in aged transgenic mice expressing amyloid precursor protein." Brain Res 853(2): 381-3.
Patients with the Lewy body variant (LBV) of Alzheimer's disease (AD) have ubiquitinated intraneuronal and neuritic accumulations of alpha-synuclein and show less neuron loss and tau pathology than other AD patients. Aged Tg2576 transgenic mice overexpressing human betaAPP695. KM670/671NL have limited neuron loss and tau pathology, but frequent ubiquitin- and alpha-synuclein-positive, tau-negative neurites resembling those seen in the LBV of AD.
Yamazaki, M., Y. Arai, et al. (2000). "Alpha-synuclein inclusions in amygdala in the brains of patients with the parkinsonism-dementia complex of Guam." J Neuropathol Exp Neurol 59(7): 585-91.
We investigated by immunohistochemistry the deposition of alpha-synuclein in the brains of deceased patients with the parkinsonism-dementia complex (PDC) of Guam. Five of 13 PDC brains showed numerous alpha-synuclein positive neuronal inclusions and abnormal neurites, chiefly in the amygdala. Similar alpha-synuclein positive lesions were observed, although to a lesser extent, in the entorhinal cortex and the dorsal vagal nucleus. No alpha-synuclein positive inclusions were observed in motor cortex or locus coeruleus, and only a small number of positive inclusions were found in the Sommer's sector, temporal cortex, or substantia nigra. Some of the alpha-synuclein positive inclusions were reminiscent of cortical Lewy bodies (LB), but many of those in the amygdala coexisted with tau-positive pretangles and/or neurofibrillary tangles (NFT) within the same neurons. In these neurons, tau-positive shells encapsulated alpha-synuclein positive central cores or irregularly shaped alpha-synuclein-positive deposition intermingled with pretangles/NFT. Thus, the present study suggests that a common mechanism may govern aggregation of alpha-synuclein and tau in the amygdala, and that aggregation of alpha-synuclein may play some role in the neurodegenerative process of a tauopathy (i.e. PDC) in which Abeta deposition is virtually absent.
Woulfe, J., H. Hoogendoorn, et al. (2000). "Monoclonal antibodies against Epstein-Barr virus cross-react with alpha-synuclein in human brain." Neurology 55(9): 1398-401.
Using antibodies generated against the latent membrane protein 1 of Epstein-Barr virus, intense immunoreactivity of Lewy bodies (in PD and dementia with Lewy bodies) and glial cytoplasmic inclusions (in multiple system atrophy) was demonstrated. ELISA and Western blotting techniques confirmed that this immunolabeling was due to cross-reactivity of the antiviral antibody with alpha-synuclein, a neuronal protein implicated in the pathogenesis of PD. This example of cross-reactivity between Epstein-Barr virus and alpha-synuclein may bear implications for further elucidating infectious or autoimmune mechanisms in PD.
Wirths, O., S. Weickert, et al. (2000). "Lewy body variant of Alzheimer's disease: alpha-synuclein in dystrophic neurites of A beta plaques." Neuroreport 11(17): 3737-41.
The contribution of alpha-synuclein accumulation in Alzheimer's disease (AD) plaques is currently a matter of scientific debate. In the present study antisera against the N- and C-terminus, the full-length protein and the central so-called non-amyloid component (NAC) domain of the alpha-synuclein protein were used to address this question in brains of cases with typical AD and of cases with the Lewy body (LB) variant of AD. In typical AD cases, none of the antisera revealed evidence for co-accumulation of alpha-synuclein with extracellular A beta peptides in plaques or in dystrophic neurites decorating the plaque core. Interestingly, cases with mixed pathology of the LB variant of AD revealed accumulation of alpha-synuclein in LBs and in dystrophic neurites of A beta plaques.
Wakabayashi, K. and H. Takahashi (2000). "[The mechanism of Lewy body formation in Parkinson's disease]." Nippon Rinsho 58(10): 2022-7.
The presence of Lewy bodies(LBs) in the substantia nigra and other subcortical nuclei is a diagnostic hallmark of Parkinson's disease(PD). Recently, two mutations in the alpha-synuclein gene in families with autosomal dominant PD were identified. Subsequent immunocytochemical studies showed that antibodies to alpha-synuclein detect all of the LBs and Lewy neurites in the brains of patients with PD. Immunoelectron microscopy revealed that the reaction product is localized within abnormal filamentous structures. Moreover, alpha-synuclein is aggregated and fibrillated in vitro. More recently, a novel protein that associates with alpha-synuclein, called synphilin-1, has been reported to be present in LBs. These findings suggest that both alpha-synuclein and synphilin-1 are precise molecular compositions of LBs.
Wakabayashi, K., S. Engelender, et al. (2000). "Synphilin-1 is present in Lewy bodies in Parkinson's disease." Ann Neurol 47(4): 521-3.
Alpha-synuclein is believed to play an important role in Parkinson's disease (PD). Mutations in the alpha-synuclein gene are responsible for familial forms of PD and alpha-synuclein protein is a major component of Lewy bodies in patients with sporadic PD. Synphilin-1 is a novel protein that we have previously found to associate in vivo with alpha-synuclein. We now show that synphilin-1 is present in Lewy bodies of patients with PD. Our data suggest that synphilin-1 could play a role in Lewy body formation and the pathogenesis of PD.
Wakabayashi, K., T. Fukushima, et al. (2000). "Juvenile-onset generalized neuroaxonal dystrophy (Hallervorden-Spatz disease) with diffuse neurofibrillary and lewy body pathology." Acta Neuropathol (Berl) 99(3): 331-6.
We describe an unusual case of Hallervorden-Spatz disease (HSD). After presenting with limb rigidospasticity at the age of 9 years, our patient developed progressive dementia, spastic tetraparesis and myoclonic movements, leading to akinetic mutism. He died of pneumonia at the age of 39 years. Autopsy revealed a severely atrophic brain, weighing 510 g. Histologically, there were iron deposits in the globus pallidus and substantia nigra pars reticulata, and numerous axonal spheroids throughout the brain and spinal cord. Neurofibrillary tangles were abundant in the hippocampus, cerebral neocortex, basal ganglia and brain stem. Neuritic plaques and amyloid deposits were absent. Lewy bodies and Lewy neurites, which were immunolabeled by anti-alpha-synuclein, were found in the brain stem, cerebral cortex and spinal gray matter. Sarkosyl-insoluble tau extracted from the temporal cortex resolved on immunoblots into three major bands of 60, 64 and 68 kDa and a minor band of 72 kDa, as reported for Alzheimer's disease. The present case, together with a few similar cases reported previously, may represent a particular subset of neuroaxonal dystrophy, i.e., HSD associated with extensive accumulation of both tau and alpha-synuclein.
Wakabayashi, K., S. Hayashi, et al. (2000). "NACP/alpha-synuclein-positive filamentous inclusions in astrocytes and oligodendrocytes of Parkinson's disease brains." Acta Neuropathol (Berl) 99(1): 14-20.
The precursor of the non-Abeta component of Alzheimer's disease amyloid (NACP), also called alpha-synuclein, is a major component of Lewy bodies in Parkinson's disease (PD) as well as of neuronal and oligodendroglial cytoplasmic inclusions in multiple system atrophy. We previously reported argyrophilic, tau-negative glial inclusions in the midbrains of patients with PD and have now conducted immunocytochemical and ultrastructural examinations. The PD glial inclusions also are immunoreactive for NACP/alpha-synuclein, but not for beta-synuclein, and ultrastructurally are composed of filamentous structures about 25-40 nm in diameter. Double immunolabeling showed that the inclusions were present in both astrocytic and oligodendroglial cells. They were located within the substantia nigra in 13 of 30 patients with PD and outside the nigra in 24. The number of inclusions was correlated with the severity of nigral neuronal loss. These findings indicate that abnormal accumulation of NACP/alpha-synuclein in glial cells is a pathological feature of PD related to its progression.
Vila, M., S. Vukosavic, et al. (2000). "Alpha-synuclein up-regulation in substantia nigra dopaminergic neurons following administration of the parkinsonian toxin MPTP." J Neurochem 74(2): 721-9.
Mutations in alpha-synuclein cause a form of familial Parkinson's disease (PD), and wild-type alpha-synuclein is a major component of the intraneuronal inclusions called Lewy bodies, a pathological hallmark of PD. These observations suggest a pathogenic role for alpha-synuclein in PD. Thus far, however, little is known about the importance of alpha-synuclein in the nigral dopaminergic pathway in either normal or pathological situations. Herein, we studied this question by assessing the expression of synuclein-1, the rodent homologue of human alpha-synuclein, in both normal and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated mice. In normal mice, detectable levels of synuclein mRNA and protein were seen in all brain regions studied and especially in ventral midbrain. In the latter, there was a dense synuclein-positive nerve fiber network, which predominated over the substantia nigra, and only few scattered synuclein-positive neurons. After a regimen of MPTP that kills dopaminergic neurons by apoptosis, synuclein mRNA and protein levels were increased significantly in midbrain extracts; the time course of these changes paralleled that of MPTP-induced dopaminergic neurodegeneration. In these MPTP-injected mice, there was also a dramatic increase in the number of synuclein-immunoreactive neurons exclusively in the substantia nigra pars compacta; all synuclein-positive neurons were tyrosine hydroxylase-positive, but none coexpressed apoptotic features. These data indicate that synuclein is highly expressed in the nigrostriatal pathway of normal mice and that it is up-regulated following MPTP-induced injury. In light of the synuclein alterations, it can be suggested that, by targeting this protein, one may modulate MPTP neurotoxicity and, consequently, open new therapeutic avenues for PD.
Van Everbroeck, B., P. Pals, et al. (2000). "Retrospective study of Creutzfeldt-Jakob disease in Belgium: neuropathological findings." Acta Neuropathol (Berl) 99(4): 358-64.
Creutzfeldt-Jakob disease (CJD) is a spongiform encephalopathy that affects about 1 in 10(6) inhabitants in most countries. Recently, a new variant of CJD has been linked to the epidemic of bovine spongiform encephalopathy. Therefore, vigilance concerning the disease's incidence has been increased. We conducted a comprehensive, nation-wide and retrospective study. In 79 Belgian autopsies, we found the characteristic triad of spongiosis, neuronal loss and reactive gliosis. The occipital cortex was most affected, while the cerebellum was mostly spared. Immunohistochemistry was performed using hydrated autoclave pretreatment and several monoclonal antibodies directed against the prion protein. We identified prion-immunoreactive patterns and locations reflecting the important heterogeneity, independently of the antibody that was used. Granular prion immunoreactivity was observed in astrocytes. We studied the regional intensity of the prion immunostaining and determined that the frontal cortex with 95% positive immunoreactivity was best suited for a biopsy. We studied the disease duration in sporadic CJD patients who showed neuropathological lesions of other neurodegenerative disorders (such as Alzheimer's disease). The study shapes the framework in which a prospective neuropathological registry will be able to function.
van der Putten, H., K. H. Wiederhold, et al. (2000). "Neuropathology in mice expressing human alpha-synuclein." J Neurosci 20(16): 6021-9.
The presynaptic protein alpha-synuclein is a prime suspect for contributing to Lewy pathology and clinical aspects of diseases, including Parkinson's disease, dementia with Lewy bodies, and a Lewy body variant of Alzheimer's disease. alpha-Synuclein accumulates in Lewy bodies and Lewy neurites, and two missense mutations (A53T and A30P) in the alpha-synuclein gene are genetically linked to rare familial forms of Parkinson's disease. Under control of mouse Thy1 regulatory sequences, expression of A53T mutant human alpha-synuclein in the nervous system of transgenic mice generated animals with neuronal alpha-synucleinopathy, features strikingly similar to those observed in human brains with Lewy pathology, neuronal degeneration, and motor defects, despite a lack of transgene expression in dopaminergic neurons of the substantia nigra pars compacta. Neurons in brainstem and motor neurons appeared particularly vulnerable. Motor neuron pathology included axonal damage and denervation of neuromuscular junctions in several muscles examined, suggesting that alpha-synuclein interfered with a universal mechanism of synapse maintenance. Thy1 transgene expression of wild-type human alpha-synuclein resulted in similar pathological changes, thus supporting a central role for mutant and wild-type alpha-synuclein in familial and idiotypic forms of diseases with neuronal alpha-synucleinopathy and Lewy pathology. These mouse models provide a means to address fundamental aspects of alpha-synucleinopathy and test therapeutic strategies.
Uversky, V. N., J. R. Gillespie, et al. (2000). "Why are "natively unfolded" proteins unstructured under physiologic conditions?" Proteins 41(3): 415-27.
"Natively unfolded" proteins occupy a unique niche within the protein kingdom in that they lack ordered structure under conditions of neutral pH in vitro. Analysis of amino acid sequences, based on the normalized net charge and mean hydrophobicity, has been applied to two sets of proteins: small globular folded proteins and "natively unfolded" ones. The results show that "natively unfolded" proteins are specifically localized within a unique region of charge-hydrophobicity phase space and indicate that a combination of low overall hydrophobicity and large net charge represent a unique structural feature of "natively unfolded" proteins.
Tiunova, A. A., K. V. Anokhin, et al. (2000). "Chicken synucleins: cloning and expression in the developing embryo." Mech Dev 99(1-2): 195-8.
Synucleins comprise a family of small intracellular proteins that have recently attracted considerable attention because of their involvement in human diseases. Mutations of alpha-synuclein has been found in several families with hereditary early-onset Parkinson's disease and accumulation of this protein in characteristic cytoplasmic inclusions is a pathohistological hallmark of several neurodegenerative diseases that have been recently classified as 'alpha;-synucleinopathies' (reviewed in Brain Res. Bull. 50 (1999) 465; J. Neurosci. Res. 58 (1999) 120; Philos. Trans. R. Soc. Lond. Biol. Sci. 354 (1999) 1101; Brain Pathol. 9 (1999) 733). Aggregates of beta-synuclein and persyn (gamma-synuclein) also have been found in dystrophic neurites associated with Parkinson's and other neurodegenerative diseases (Proc. Natl. Acad. Sci. USA 96 (1999) 13450; and our unpublished observations). Moreover, persyn has been implicated in malignization of breast tumours (Cancer Res. 57 (1997) 759; Cancer Res. 59 (1999) 742; Hum. Mol. Genet. 7 (1998) 1417). All synucleins have distinct, although overlapping, patterns of expression in the embryonic, postnatal and adult mammalian nervous systems, suggesting important, although still not clear, biological functions in neuronal developing. Chicken embryo is a unique object for developmental studies that allows in vivo manipulations not always possible for mammalian embryos. Studies of synucleins expression in this model system could shed light on their functions in the developing nervous system. We cloned three chicken synucleins from the embryonic neural cDNA libraries and studied their expression in normal chicken embryonic tissues by Northern and in situ hybridization with specific probes. Our results demonstrate that primary structures and expression patterns of synucleins are similar in birds and mammals, suggesting that conserved function of synucleins is important for embryonic development of vertebrates.
Terada, S., H. Ishizu, et al. (2000). "Tau-negative astrocytic star-like inclusions and coiled bodies in dementia with Lewy bodies." Acta Neuropathol (Berl) 100(5): 464-8.
To evaluate glial lesions in cases of dementia with Lewy bodies (DLB), we studied the brains of four patients with DLB. Astrocytic star-like inclusions, which resembled tufted astrocytic fibrillary tangles in shape, were found in the cortex of two of these cases. In addition, coiled bodies were found in the white matter of the cerebrum in two cases. The astrocytic star-like inclusions were immunohistochemically negative for tau protein, ubiquitin and alpha-synuclein. The coiled bodies were immunohistochemically negative for tau protein but immunopositive for ubiquitin and alpha-synuclein. These results suggest that in DLB a primary degenerative process takes place in both glial cells and neurons.
Tan, E. K., T. Matsuura, et al. (2000). "Polymorphism of NACP-Rep1 in Parkinson's disease: an etiologic link with essential tremor?" Neurology 54(5): 1195-8.
An allele (263bp) of the nonamyloid component of plaques (NACP)-Repl polymorphism has shown association with sporadic PD in a German population. The authors studied this polymorphism in 100 American PD patients and 100 healthy controls. The authors also studied 46 essential tremor (ET) and 55 Huntington's disease (HD) patients. Allele 263bp was significantly higher in PD patients (OR = 3.86) and ET patients (OR = 6.42) but not HD patients, compared with healthy controls. The association of allele 263bp with PD and ET suggests a possible etiologic link between these two conditions.
Takeda, A., M. Hashimoto, et al. (2000). "C-terminal alpha-synuclein immunoreactivity in structures other than Lewy bodies in neurodegenerative disorders." Acta Neuropathol (Berl) 99(3): 296-304.
alpha-Synuclein is a presynaptic terminal protein that accumulates abnormally in plaques in Alzheimer's disease (AD), in Lewy bodies in Lewy body disease (LBD) and in filamentous inclusions in multiple system atrophy. Since it has been previously shown that proteinase K or formic acid pretreatment enhances alpha-synuclein immunoreactivity in Lewy bodies and plaques, we hypothesized that the immunoreactivity in tangles, glial cells and Pick bodies might be revealed by such pretreatment. Brain sections from patients with AD, LBD, progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and Pick's disease were pretreated with proteinase K or formic acid and immunostained with antibodies against the N-terminal, C-terminal or non-amyloid beta component of AD amyloid (NAC) regions of alpha-synuclein. This study showed that after proteinase K (but not formic acid) pretreatment the anti-C terminus antibody immunostained neurofibrillary tangles of AD, PSP and CBD, and glial inclusions of PSP and CBD, as well as Pick bodies. Western blot analysis confirmed that in cases other than LBD, the anti-C terminus antibodies also recognized the native alpha-synuclein band and no cross-reactive bands were observed. In contrast, in LBD, after formic acid pretreatment with the anti-NAC antibody astroglial cells and granular neurons were immunostained. The N-terminal region antibody only recognized the lesions in LBD cases and not those of other neurodegenerative disorders. These results support the view that different fragments of alpha-synuclein might play an important role in the pathogenesis of several neurodegenerative disorders.
Takahashi, M., E. Iseki, et al. (2000). "Cyclin-dependent kinase 5 (Cdk5) associated with Lewy bodies in diffuse Lewy body disease." Brain Res 862(1-2): 253-6.
We investigated the cyclin-dependent kinase (Cdk) 5 distribution pattern in diffuse Lewy body disease brains using immunohistochemistry. Cdk5 immunoreactivity was detected in both brainstem-type Lewy bodies (LBs) and cortical LBs. The number of Cdk5-positive LBs was less than that of ubiquitin- or alpha-synuclein-positive LBs, and more than that of phosphorylated neurofilament-positive LBs. Immunoelectron microscopy revealed Cdk5-immunolabeled granulo-filamentous components in LBs and LB-related neurites. These data suggest that Cdk5 may be associated with LB formation.
Tabrizi, S. J., M. Orth, et al. (2000). "Expression of mutant alpha-synuclein causes increased susceptibility to dopamine toxicity." Hum Mol Genet 9(18): 2683-9.
Mutations of the alpha-synuclein gene have been identified in autosomal dominant Parkinson's disease (PD). Transgenic mice overexpressing wild-type human alpha-synuclein develop motor impairments, intraneuronal inclusions and loss of dopaminergic terminals in the striatum. To study the mechanism of action through which mutant alpha-synuclein toxicity is mediated, we have generated stable, inducible cell models expressing wild-type or PD-associated mutant (G209A) alpha-synuclein in human-derived HEK293 cells. Increased expression of either wild-type or mutant alpha-synuclein resulted in the formation of cytoplasmic aggregates which were associated with the vesicular (including monoaminergic) compartment. Expression of mutant alpha-synuclein induced a significant increase in sensitivity to dopamine toxicity compared with the wild-type protein expression. These results provide an explanation for the preferential dopaminergic neuronal degeneration seen in both the PD G209A mutant alpha-synuclein families and suggest that similar mechanisms may underlie or contribute to cell death in sporadic PD.
Souza, J. M., B. I. Giasson, et al. (2000). "Chaperone-like activity of synucleins." FEBS Lett 474(1): 116-9.
Synucleins are a family of small proteins that are predominantly expressed in neurons. The functions of the synucleins are not entirely understood, but they have been implicated in the pathogenesis of several neurodegenerative diseases. Our data show that alpha-, beta- or gamma-synuclein suppresses the aggregation of thermally denatured alcohol dehydrogenase and chemically denatured insulin. The A53T but not the A30P mutant alpha-synuclein was able to inhibit the aggregation of insulin and the chaperone-like activity of alpha-synuclein was lost upon removal of its C-terminal residues 98-140. These results demonstrate that synucleins with the exception of the A30P mutant possess chaperone-like activity.
Souza, J. M., B. I. Giasson, et al. (2000). "Dityrosine cross-linking promotes formation of stable alpha -synuclein polymers. Implication of nitrative and oxidative stress in the pathogenesis of neurodegenerative synucleinopathies." J Biol Chem 275(24): 18344-9.
Intracellular proteinaceous aggregates are hallmarks of many common neurodegenerative disorders, and recent studies have shown that alpha-synuclein is a major component of several pathological intracellular inclusions, including Lewy bodies in Parkinson's disease (PD) and glial cell inclusions in multiple system atrophy. However, the molecular mechanisms underlying alpha-synuclein aggregation into filamentous inclusions remain unknown. Since oxidative and nitrative stresses are potential pathogenic mediators of PD and other neurodegenerative diseases, we asked if oxidative and/or nitrative events alter alpha-synuclein and induce it to aggregate. Here we show that exposure of human recombinant alpha-synuclein to nitrating agents (peroxynitrite/CO(2) or myeloperoxidase/H(2)O(2)/nitrite) induces formation of nitrated alpha-synuclein oligomers that are highly stabilized due to covalent cross-linking via the oxidation of tyrosine to form o,o'-dityrosine. We also demonstrate that oxidation and nitration of pre-assembled alpha-synuclein filaments stabilize these filaments to withstand denaturing conditions and enhance formation of SDS-insoluble, heat-stable high molecular mass aggregates. Thus, these data suggest that oxidative and nitrative stresses are involved in mechanisms underlying the pathogenesis of Lewy bodies and glial cell inclusions in PD and multiple system atrophy, respectively, as well as alpha-synuclein pathologies in other synucleinopathies.
Sommer, B., S. Barbieri, et al. (2000). "Mouse models of alpha-synucleinopathy and Lewy pathology." Exp Gerontol 35(9-10): 1389-403.
The discovery of two missense mutations (A53T and A30P) in the gene encoding the presynaptic protein alpha-synuclein (alphaSN) that are genetically linked to rare familial forms of Parkinson's disease and its accumulation in Lewy bodies and Lewy neurites has triggered several attempts to generate transgenic mice overexpressing human alphaSN. Analogous to a successful strategy for the production of transgenic animal models for Alzheimer's disease we generated mice expressing wildtype and the A53T mutant of human alphaSN in the nervous system under control of mouse Thy1 regulatory sequences. These animals develop neuronal alpha-synucleinopathy, striking features of Lewy pathology, neuronal degeneration and motor defects. Neurons in brainstem and motor neurons appeared particularly vulnerable. Motor neuron pathology included axonal damage and denervation of neuromuscular junctions, suggesting that alphaSN may interfere with a universal mechanism of synapse maintenance. Thy1-transgene expression of wildtype human alphaSN resulted in comparable pathological changes thus supporting a central role for mutant and wildtype alphaSN in familial and idiopathic forms of diseases with neuronal alpha-synucleinopathy and Lewy pathology. The mouse models provide means to address fundamental aspects of alpha-synucleinopathy and to test therapeutic strategies.
Solano, S. M., D. W. Miller, et al. (2000). "Expression of alpha-synuclein, parkin, and ubiquitin carboxy-terminal hydrolase L1 mRNA in human brain: genes associated with familial Parkinson's disease." Ann Neurol 47(2): 201-10.
Mutations in the alpha-synuclein, parkin, and ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) genes have been linked to some cases of familial Parkinson's disease. To provide insight into how these genes may relate to each other and contribute to the pathology of Parkinson's disease, their expression was examined in normal human brain. Tissue sections from multiple regions of 11 normal human brains were hybridized with radiolabeled and digoxygenin-labeled cRNA probes for alpha-synuclein, parkin, and UCH-L1 mRNA. Expression of each of these three genes was predominantly neuronal. Alpha-synuclein and parkin mRNAs were expressed in a restricted number of brain regions, whereas UCH-L1 mRNA was more uniformly expressed throughout brain. The melanin-containing dopamine neurons of the substantia nigra had particularly robust expression. The expression patterns of alpha-synuclein and parkin mRNAs were similar, suggesting that these two proteins may be involved in common pathways contributing to the pathophysiology of Parkinson's disease.
Shoji, M., Y. Harigaya, et al. (2000). "Accumulation of NACP/alpha-synuclein in lewy body disease and multiple system atrophy." J Neurol Neurosurg Psychiatry 68(5): 605-8.
OBJECTIVES: NACP/alpha-synuclein is an aetiological gene product in familial Parkinson's disease. To clarify the pathological role of NACP/alpha-synuclein in sporadic Parkinson's disease and other related disorders including diffuse Lewy body disease (DLBD) and multiple system atrophy (MSA), paraffin sections were examined immunocytochemically using anti-NACP/alpha-synuclein antibodies. METHODS: A total of 58 necropsied brains, from seven patients with Parkinson's disease, five with DLBD, six with MSA, 12 with Alzheimer's disease, one with Down's syndrome, one with amyotrophic lateral sclerosis (ALS), three with ALS and dementia, one with Huntington's disease, two with progressive supranuclear palsy (PSP), one with Pick's disease, one with myotonic dystrophy, and three with late cerebellar cortical atrophy (LCCA), and 15 elderly normal controls were examined. RESULTS: In addition to immunoreactive Lewy bodies, widespread accumulation of NACP/alpha-synuclein was found in neurons and astrocytes from the brainstem and basal ganglia to the cerebral cortices in Parkinson's disease/DLBD. NACP/alpha-synuclein accumulates in oligodendrocytes from the spinal cord, the brain stem to the cerebellar white matter, and inferior olivary neurons in MSA. These widespread accumulations were not seen in other types of dementia or spinocerebellar ataxia. CONCLUSION: Completely different types of NACP/alpha-synuclein accumulation in Parkinson's disease/DLBD and MSA suggest that accumulation is a major step in the pathological cascade of both diseases and provides novel strategies for the development of therapies.
Shin, H. J., E. K. Lee, et al. (2000). "Eosin interaction of alpha-synuclein leading to protein self-oligomerization." Biochim Biophys Acta 1481(1): 139-46.
Among various dyes including congo red, thioflavin S, thioflavin T, eosin, rhodamine 6G, and phenol red, the eosin was the only dye that induced self-oligomerization of alpha-synuclein in the presence of a chemical coupling reagent of N-(ethoxycarbonyl)-2-ethoxy-1, 2-dihydroquinoline. To analyze chemical nature of the eosin interaction with alpha-synuclein, the phenomenon of self-oligomerization was further examined with eosin congeners such as ethyl eosin, eosin B, phloxine B, erythrosin B, and rose bengal. The followings are the conclusions we have reached. First of all, intactness of the benzoate moiety of eosin and the negative charge on the carboxylic group of the dye are important factors leading to the specific interaction with alpha-synuclein. Secondly, the localized negative charge on the xanthene moiety of eosin is another critical factor for the interaction. As far as substituting halides are concerned, bromides and iodides on the xanthene moiety of the dyes do not make any difference on the alpha-synuclein interaction because both eosin and erythrosin B have induced the common phenomenon of self-oligomerization. The binding curve between eosin and alpha-synuclein was sigmoidal as the dye concentrations were increased. A double reciprocal plot of the saturation curve showed that the maximum number of eosin binding sites on alpha-synuclein was 1.85 with a dissociation constant of 390 microM. The dye binding to the protein appeared to occur via a positive cooperativity. The eosin binding site(s) was suggested to be located predominantly on the NAC region and partly related to the acidic C-terminus of alpha-synuclein. It has been, therefore, expected that this information might be useful to develop alpha-synuclein interactive molecules, which could provide eventual preventive or possible therapeutic means against various alpha-synuclein related disorders including Parkinson's disease.
Shin, E. C., S. E. Cho, et al. (2000). "Expression patterns of alpha-synuclein in human hematopoietic cells and in Drosophila at different developmental stages." Mol Cells 10(1): 65-70.
Alpha-synuclein, a presynaptic protein of the central nervous system, has been implicated in the synaptic events such as neuronal plasticity during development and learning, and neuronal degeneration under pathological conditions. As an effort to understand the biological function of alpha-synuclein, we examined the expression patterns of alpha-synuclein in various human hematopoietic cells, and in Drosophila at different developmental stages. The alpha-synuclein was ubiquitously expressed in all the tested hematopoietic cells including T cells, B cells, NK cells, and monocytes, as well as in the lymphoma cell lines, Jurkat and K562. A potential alpha-synuclein homologue was also expressed in Drosophila, and its expression appeared to be temporally and spatially regulated during development. Our data suggest that alpha-synuclein may function in invertebrates as well as in vertebrates and its function may not be restricted to the neuron.
Shashidharan, P., P. F. Good, et al. (2000). "TorsinA accumulation in Lewy bodies in sporadic Parkinson's disease." Brain Res 877(2): 379-81.
Parkinson's disease (PD) is a neurodegnerative disorder that is pathologically characterized by the presence of Lewy bodies in the brain. We show that Lewy bodies in PD are strongly immunoreactive for torsinA, the protein product of the DYT1 gene, which is associated with primary generalized dystonia. In the substantia nigra, torsinA immunoreactivity is localized to the periphery of Lewy bodies, whereas, in cortical Lewy bodies it is uniformly distributed. The significance of this finding is unknown, but may implicate torsinA in neuronal dysfunction that occurs in PD as well as in primary dystonia.
Serpell, L. C., J. Berriman, et al. (2000). "Fiber diffraction of synthetic alpha-synuclein filaments shows amyloid-like cross-beta conformation." Proc Natl Acad Sci U S A 97(9): 4897-902.
Filamentous inclusions made of alpha-synuclein constitute the defining neuropathological characteristic of Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Rare familial cases of Parkinson's disease are associated with mutations A53T and A30P in alpha-synuclein. We report here the assembly properties and secondary structure characteristics of recombinant alpha-synuclein. Carboxy-terminally truncated human alpha-synuclein (1-87) and (1-120) showed the fastest rates of assembly, followed by human A53T alpha-synuclein, and rat and zebra finch alpha-synuclein. Wild-type human alpha-synuclein and the A30P mutant showed slower rates of assembly. Upon shaking, filaments formed within 48 h at 37 degrees C. The related proteins beta- and gamma-synuclein only assembled after several weeks of incubation. Synthetic human alpha-synuclein filaments were decorated by an antibody directed against the carboxy-terminal 10 amino acids of alpha-synuclein, as were filaments extracted from dementia with Lewy bodies and multiple system atrophy brains. Circular dichroism spectroscopy indicated that alpha-synuclein undergoes a conformational change from random coil to beta-sheet structure during assembly. X-ray diffraction and electron diffraction of the alpha-synuclein assemblies showed a cross-beta conformation characteristic of amyloid.
Sato, K., S. Sato, et al. (2000). "[A 67-year-old man with progressive disturbance of gait]." No To Shinkei 52(7): 643-53.
We report a 67-year-old man with progressive disturbance of gait. He was well until the spring of 1993 (62 years of the age), when he noted an onset of unsteady gait. He also noted that he started to have a difficulty in playing tennis, in which he became unable to hit the ball with his racket. He also noted parkinsonian features such as bradykinesia and loss of hand dexterity. He was treated with levodopa, which did not improve his symptoms. His MRI revealed marked atrophy of the cerebellum and the pons. The criss-cross high signal lesion was seen in the center of the pons. The third ventricle was dilated. The putamen was unremarkable. His subsequent course was complicated by easy to fall, difficulty in swallowing with episodes of aspiration pneumonia. He also developed nocturnal apneustic episodes. He was admitted to our hospital on November 15, 1998, when he was 67 years of the age. He had low grade fever and low blood pressure (98/70). He was anemic but not icteric. Tumors were palpated in his jaw, anterior chest, and in the left arm. He was alert but unable to convey his desire because of dyspnea and tracheostomy. His gaze was slightly restricted in the horizontal direction and markedly so in the vertical direction. Motor functions were difficult to evaluate. His clinical course was complicated by atelectasis of the right lung and pleural effusion. He developed marked edema and oliguria. He developed sudden bradycardia and expired on December 26, 1998. He was discussed in a neurological CPC and the chief discussant arrived at the conclusion that the patient had multiple system atrophy. Majority of the audience agreed with this diagnosis. Post-mortem examination revealed a lung cancer in the right lung (undifferentiated adenocarcinoma) with metastases to the liver, kidneys, lymph nodes, pericardium, pleura, skin, bone marrow, and the brain. Neuropathologic examination revealed marked atrophy of the pons and the cerebellum. The putamen showed brownish discoloration and atrophic changes. The substantia nigra showed marked neuronal loss and gliosis. Oligodendrocytic inclusion bodies (alpha-synuclein positive) were seen in the putamen, globus pallidus, substantia nigra, pontine nucleus, cerebellar white matter, internal capsule, cerebral peduncle, and the spinal cord. These findings are consistent with the pathologic diagnosis of multiple system atrophy. What was interesting to us was the presence of neurofibrillary tangles in the substantia nigra, nucleus ruber, globus pallidus, and subthalamic nucleus. Tuft-shaped astrocytes were also seen. This patient appears to be a rare example of combination of MSA and PSP.
Saito, Y., M. Kawai, et al. (2000). "Widespread expression of alpha-synuclein and tau immunoreactivity in Hallervorden-Spatz syndrome with protracted clinical course." J Neurol Sci 177(1): 48-59.
Hallervorden-Spatz syndrome (HSS) is a rare autosomal recessive disorder clinically characterized by extrapyramidal signs and progressive dementia. In a typical case, the clinical symptoms become apparent during late childhood, and usually the course is protracted over a decade or more. We recently had an opportunity to study the brains of two cases of HSS with a clinical course of over 30 years. Case 1 was a 44-year-old female and case 2 was a 37-year-old male. Grossly, the brains showed severe fronto-temporal lobar atrophy with abundant spheroids and mild iron deposits in the globus pallidus, associated with features of motor neuron disease. In addition, there was diffuse sponginess in the atrophic cortex as well as widespread Alzheimer's neurofibrillary tangles (NFTs) and Lewy bodies (LBs) in the cortical and subcortical regions, including the spinal cord. Ultrastructurally, NFTs were composed of paired helical filaments, and LBs of central dense cores with radiating fibrils. Discrete immunostaining was demonstrated in NFTs and neuropil threads with various antibodies against phosphorylated tau, and in LBs with antibody against alpha-synuclein. In addition, diffuse, overlapping immunoreactivity of alpha-synuclein and phosphorylated tau was seen within the cytoplasm of many neurons. However, when LBs and NFTs coexisted within the same neurons, they were clearly segregated. The findings of our present cases as well as those reported in the literature may indicate that simultaneous and extensive occurrence of abnormal phosphorylation of tau and accumulation of alpha-synuclein may constitute cardinal pathological features of HSS with protracted clinical course.
Saha, A. R., N. N. Ninkina, et al. (2000). "Induction of neuronal death by alpha-synuclein." Eur J Neurosci 12(8): 3073-7.
The molecular and cellular mechanisms underlying neuronal loss in neurodegenerative diseases are unclear. It is generally thought that aggregation of mutated, abnormally modified or abnormally folded proteins leads to the accumulation of extracellular, intracellular or intranuclear deposits that severely compromise cell physiology, leading to the death of the affected neurons. However, there is growing evidence that neuronal apoptosis in the absence of obvious pathological deposits could have a serious impact on the pathogenesis of neurodegenerative diseases. alpha-Synuclein has been implicated in aetiology and pathogenesis of certain neurodegenerative diseases, although the precise role of this protein in neurodegeneration is uncertain. The normal functions of alpha-synuclein and other members of the synuclein family in the development and function of the nervous system also remain elusive. Here we show that overexpression of wild-type and mutant forms of alpha-synuclein in cultured neurons, but not the closely related persyn (gamma-synuclein), causes apoptosis. These findings suggest that abnormalities of alpha-synuclein metabolism could lead to the neuronal loss occurring in certain forms of neurodegeneration before the formation of characteristic pathological lesions.
Rozemuller, A. J., P. Eikelenboom, et al. (2000). "Activated microglial cells and complement factors are unrelated to cortical Lewy bodies." Acta Neuropathol (Berl) 100(6): 701-8.
Inflammatory mechanisms have been demonstrated in Alzheimer's disease (AD) but their presence in other neurodegenerative disorders is not well documented. Complement factors and activated microglia have been reported in the substantia nigra of Parkinson's disease (PD). In the present study we investigated the cingulate gyrus of 25 autopsied patients with clinically and neuropathologically well-documented PD, with or without dementia, for the presence of (activated) microglial cells and their relation with Lewy body (LB)-bearing neurons. In addition, we studied the presence of complement factors in LBs. Of the 25 patient, 15 were clinically demented, fulfilling criteria for dementia with LBs (DLB); 7 also fulfilled CERAD morphological criteria for probable or definite Alzheimer type of dementia. Microglia clustering was seen around congophilic plaques with or without tau pathology. Microglial cells were not associated with LB-bearing neurons or noncongophilic plaques. The cortex of DLB patients without AD plaques did not show more microglial cells than the cortex of non-demented controls. The number of microglia was the lowest in young control patients who died immediately after trauma. Complement factor C3d was occasionally seen in diffusely ubiquinated neurons but late complement factors were not detected in these neurons. Double staining for complement and alpha-synuclein was negative, suggesting the absence of complement in LBs. In contrast, AD plaques in the same sections showed complement factors C3c, C3d, C1q and C5-9. In conclusion, we have found no evidence that inflammatory mechanism are involved in LB formation in cerebral cortex.
Rochet, J. C., K. A. Conway, et al. (2000). "Inhibition of fibrillization and accumulation of prefibrillar oligomers in mixtures of human and mouse alpha-synuclein." Biochemistry 39(35): 10619-26.
Parkinson's disease (PD) is a neurodegenerative disorder attributed to the loss of dopaminergic neurons from the substantia nigra. Some surviving neurons are characterized by cytoplasmic Lewy bodies, which contain fibrillar alpha-synuclein. Two mutants of human alpha-synuclein (A53T and A30P) have been linked to early-onset, familial PD. Oligomeric forms of these mutants accumulate more rapidly and/or persist for longer periods of time than oligomeric, human wild-type alpha-synuclein (WT), suggesting a link between oligomerization and cell death. The amino acid sequences of the mouse protein and WT differ at seven positions. Mouse alpha-synuclein, like A53T, contains a threonine residue at position 53. We have assessed the conformational properties and fibrillogenicity of the murine protein. Like WT and the two PD mutants, mouse alpha-synuclein adopts a "natively unfolded" or disordered structure. However, at elevated concentrations, the mouse protein forms amyloid fibrils more rapidly than WT, A53T, or A30P. The fibrillization of mouse alpha-synuclein is slowed by WT and A53T. Inhibition of fibrillization leads to the accumulation of nonfibrillar, potentially toxic oligomers. The results are relevant to the interpretation of the phenotypes of transgenic animal models of PD and suggest a novel approach for testing the cause and effect relationship between fibrillization and neurodegeneration.
Riess, O., W. Kuhn, et al. (2000). "Genetic influence on the development of Parkinson's disease." J Neurol 247 Suppl 2: II69-74.
In the last few years, the genetic contribution to Parkinson's disease has gained major attention and resulted in the identification of four gene loci in autosomal dominant and autosomal recessive Parkinson's disease. Several mutations in two genes have been shown to be responsible for neuronal cell death in Parkinson's disease. One of the gene products involved, alpha-synuclein, is a major component of Lewy bodies, the neuropathological feature of Parkinson's disease. In contrast, mutations in the parkin gene are associated with parkinsonism without Lewy body pathology. The elucidation of polygenic changes in the dopamine pathway, mitochondrial dysfunction, and of xenobiotic metabolism is technically now possible by means of association and genotype studies. The increasing knowledge of the pathogenesis of Parkinson's disease at a molecular level will have important implications for the development of individual therapeutic strategies to prevent disease progression.
Richter-Landsberg, C., M. Gorath, et al. (2000). "alpha-synuclein is developmentally expressed in cultured rat brain oligodendrocytes." J Neurosci Res 62(1): 9-14.
Although a neuronal protein, alpha-synuclein is a major component of glial cytoplasmic inclusions (GCIs) in oligodendrocytes of multiple system atrophy (MSA) brains. Because alpha-synuclein has not been identified in oligodendrocytes of normal brains, we examined cultured rat brain oligodendrocytes during in vitro development and showed that alpha-synuclein mRNA and protein are present in cultured oligodendrocytes. The expression of alpha-synuclein was developmentally regulated; it increased to peak levels at 2 or 3 days in culture but declined thereafter. Indirect immunofluorescence further shows that alpha-synuclein was localized predominantly in cell bodies and primary processes of oligodendroglia. Thus, GCIs may be a consequence of altered rather than de novo expression of alpha-synuclein in MSA oligodendrocytes.
Raghavan, R., C. L. White, 3rd, et al. (2000). "Alpha-synuclein expression in central nervous system tumors showing neuronal or mixed neuronal/glial differentiation." J Neuropathol Exp Neurol 59(6): 490-4.
Alpha-synuclein (alpha-synuclein) is a member of a family of cytoplasmic proteins found predominantly and abundantly in the brain, and concentrated in pre-synaptic nerve terminals, near vesicles. We hypothesized that an antibody to alpha-synuclein could be a useful marker of neuronal differentiation in central nervous system (CNS) tumors. Twenty tumors known to have neuronal or mixed neuronal/glial differentiation ( 11 gangliogliomas, 2 anaplastic gangliogliomas, 5 gangliocytomas, and 2 ganglioneuroblastomas), 5 central neurocytomas, and 1 dysembryoplastic neuroepithelial tumor (DNET) were immunostained with a mouse monoclonal antibody raised against human alpha-synuclein. Intense cytoplasmic staining, in some instances extending into the perikarya, was seen in 6 of 11 gangliogliomas, 2 of 2 anaplastic gangliogliomas, and 2 of 2 ganglioneuroblastomas. Alpha-synuclein-positive cells were usually large in size, resembled dysmorphic neurons, and were variably immunoreactive for anti-neurofilament and/or anti-synaptophysin antibodies. In contrast, central neurocytomas, gangliocytomas, and the DNET were negative for cytoplasmic alpha-synuclein expression. Our findings indicate that alpha-synuclein is expressed within the neuronal component of mixed tumors of the CNS displaying more than 1 histophenotype, and/or showing different degrees of anaplasia. Based on currently available data, we conclude that cytoplasmic alpha-synuclein expression is a marker of maturing neurons in these tumors.
Pronin, A. N., A. J. Morris, et al. (2000). "Synucleins are a novel class of substrates for G protein-coupled receptor kinases." J Biol Chem 275(34): 26515-22.
G protein-coupled receptor kinases (GRKs) specifically recognize and phosphorylate the agonist-occupied form of numerous G protein-coupled receptors (GPCRs), ultimately resulting in desensitization of receptor signaling. Until recently, GPCRs were considered to be the only natural substrates for GRKs. However, the recent discovery that GRKs also phosphorylate tubulin raised the possibility that additional GRK substrates exist and that the cellular role of GRKs may be much broader than just GPCR regulation. Here we report that synucleins are a novel class of GRK substrates. Synucleins (alpha, beta, gamma, and synoretin) are 14-kDa proteins that are highly expressed in brain but also found in numerous other tissues. alpha-Synuclein has been linked to the development of Alzheimer's and Parkinson's diseases. We found that all synucleins are GRK substrates, with GRK2 preferentially phosphorylating the alpha and beta isoforms, whereas GRK5 prefers alpha-synuclein as a substrate. GRK-mediated phosphorylation of synuclein is activated by factors that stimulate receptor phosphorylation, such as lipids (all GRKs) and Gbetagamma subunits (GRK2/3), suggesting that GPCR activation may regulate synuclein phosphorylation. GRKs phosphorylate synucleins at a single serine residue within the C-terminal domain. Although the function of synucleins remains largely unknown, recent studies have demonstrated that these proteins can interact with phospholipids and are potent inhibitors of phospholipase D2 (PLD2) in vitro. PLD2 regulates the breakdown of phosphatidylcholine and has been implicated in vesicular trafficking. We found that GRK-mediated phosphorylation inhibits synuclein's interaction with both phospholipids and PLD2. These findings suggest that GPCRs may be able to indirectly stimulate PLD2 activity via their ability to regulate GRK-promoted phosphorylation of synuclein.
Piao, Y. S., K. Wakabayashi, et al. (2000). "Aggregation of alpha-synuclein/NACP in the neuronal and glial cells in diffuse Lewy body disease: a survey of six patients." Clin Neuropathol 19(4): 163-9.
BACKGROUND : alpha-Synuclein is now known to be a major component of Lewy bodies (LBs) in Parkinson's disease (PD) and diffuse Lewy body disease (DLBD). Recently, cytoplasmic aggregation of alpha-synuclein has also been reported to occur in glial cells in these diseases. METHODS: We have conducted an immunohistochemical survey to clarify in detail the distribution of alpha-synuclein aggregates in the central nervous system of patients with DLBD. The cerebrum, brainstem, cerebellum and spinal cord of six patients with DLBD were examined immunohistochemically using anti-alpha-synuclein antibodies. RESULTS: In all patients, alpha-synuclein-immunoreactive cytoplasmic inclusions, including those with profiles of typical LBs, were visualized in neurons of the cerebral neocortex, hippocampus, amygdaloid nucleus, hypothalamus, brainstem pigmented nuclei and reticular formation. In some of these patients, similar spherical cytoplasmic inclusions were also detected in neurons of the olfactory bulb, basal ganglia, thalamus, the subthalamic, pontine, inferior olivary and cerebellar dentate nuclei, and in the spinal gray matter. Moreover, alpha-synuclein-immunoreactive cytoplasmic inclusions, which appeared circular or coil-like in shape, were found in glial cells. In four patients with longstanding DLBD, these cytoplasmic inclusions were distributed widely in brain areas, including brainstem, basal ganglia, and cerebral and cerebellar white matter. CONCLUSION: The widespread occurrence of alpha-synuclein aggregates in both neuronal and glial cells is a pathological feature in patients suffering from DLBD.
Perrin, R. J., W. S. Woods, et al. (2000). "Interaction of human alpha-Synuclein and Parkinson's disease variants with phospholipids. Structural analysis using site-directed mutagenesis." J Biol Chem 275(44): 34393-8.
alpha-Synuclein has been centrally implicated in neurodegenerative disease, and a normal function in developmental synaptic plasticity has been suggested by studies in songbirds. A variety of observations suggest the protein partitions between membrane and cytosol, a behavior apparently conferred by a conserved structural similarity to the exchangeable apolipoproteins. Here we show that the capacity to bind lipids is broadly distributed across exons 3, 4, and 5 (encoding residues 1-102). Binding to phosphatidylserine-containing vesicles requires the presence of all three exons, while binding to phosphatidic acid can be mediated by any one of the three. Consistent with a "class A2" helical binding mechanism, lipid association is disrupted by introduction of charged residues along the hydrophobic face of the predicted alpha-helix and also by biotinylation of conserved lysines (which line the interfacial region). Circular dichroism spectroscopy reveals a general correlation between the amount of lipid-induced alpha-helix content and the degree of binding to PS-containing vesicles. Two point mutations associated with Parkinson's disease have little (A30P) or no (A53T) effect on lipid binding or alpha-helicity. These results are consistent with the hypothesis that alpha-synuclein's normal functions depend on an ability to undergo a large conformational change in the presence of specific phospholipids.
Paik, S. R., H. J. Shin, et al. (2000). "Metal-catalyzed oxidation of alpha-synuclein in the presence of Copper(II) and hydrogen peroxide." Arch Biochem Biophys 378(2): 269-77.
alpha-Synuclein is a component of abnormal protein depositions of Lewy bodies and senile plaques found in Parkinson's and Alzheimer's diseases, respectively. By using chemical coupling reagents such as dicyclohexylcarbodiimide or N-(ethoxycarbonyl)-2-ethoxy-1, 2-dihydroquinoline, the protein was shown to experience self-oligomerization in the presence of either copper(II) or Abeta25-35. The oligomers which appeared as a ladder on a 10-20% Tricine/SDS-PAGE have been suggested to participate in the formation of protein aggregations by possibly providing a nucleation center. Since oxidatively modified protein could increase its own tendency toward protein aggregation, metal-catalyzed oxidation of alpha-synuclein has been examined with copper(II) and hydrogen peroxide in the absence of the coupling reagent. Intriguingly, the protein was also self-oligomerized into an SDS-resistant ladder on the gel. This biochemically specific copper-mediated oxidative oligomerization was shown to be dependent upon the acidic C-terminus of alpha-synuclein because the C-terminally truncated proteins such as alpha-syn114 and alpha-syn97 were not affected by the metal and hydrogen peroxide. More importantly, the oxidative oligomerization was synergistically enhanced by the presence of Abeta25-35, indicating that the peptide interaction with alpha-synuclein facilitated the copper(II) binding to the acidic C-terminus and subsequent oxidative crosslinking. It has been, therefore, suggested that abnormalities in copper and H(2)O(2) homeostasis and certain pathological factors functionally similar to the Abeta25-35 could play critical roles in the metal-catalyzed oxidative oligomerization of alpha-synuclein, which may lead to possible protein aggregation and neurodegenerations.
Ostrerova-Golts, N., L. Petrucelli, et al. (2000). "The A53T alpha-synuclein mutation increases iron-dependent aggregation and toxicity." J Neurosci 20(16): 6048-54.
Parkinson's disease (PD) is the most common motor disorder affecting the elderly. PD is characterized by the formation of Lewy bodies and death of dopaminergic neurons. The mechanisms underlying PD are unknown, but the discoveries that mutations in alpha-synuclein can cause familial PD and that alpha-synuclein accumulates in Lewy bodies suggest that alpha-synuclein participates in the pathophysiology of PD. Using human BE-M17 neuroblastoma cells overexpressing wild-type, A53T, or A30P alpha-synuclein, we now show that iron and free radical generators, such as dopamine or hydrogen peroxide, stimulate the production of intracellular aggregates that contain alpha-synuclein and ubiquitin. The aggregates can be identified by immunocytochemistry, electron microscopy, or the histochemical stain thioflavine S. The amount of aggregation occurring in the cells is dependent on the amount of alpha-synuclein expressed and the type of alpha-synuclein expressed, with the amount of alpha-synuclein aggregation following a rank order of A53T > A30P > wild-type > untransfected. In addition to stimulating aggregate formation, alpha-synuclein also appears to induce toxicity. BE-M17 neuroblastoma cells overexpressing alpha-synuclein show up to a fourfold increase in vulnerability to toxicity induced by iron. The vulnerability follows the same rank order as for aggregation. These data raise the possibility that alpha-synuclein acts in concert with iron and dopamine to induce formation of Lewy body pathology in PD and cell death in PD.
Okochi, M., J. Walter, et al. (2000). "Constitutive phosphorylation of the Parkinson's disease associated alpha-synuclein." J Biol Chem 275(1): 390-7.
alpha-Synuclein has been implicated in the pathogenesis of Parkinson's disease, since rare autosomal dominant mutations are associated with early onset of the disease and alpha-synuclein was found to be a major constituent of Lewy bodies. We have analyzed alpha-synuclein expression in transfected cell lines. In pulse-chase experiments alpha-synuclein appeared to be stable over long periods (t((1)/(2)) 54 h) and no endoproteolytic processing was observed. alpha-Synuclein was constitutively phosphorylated in human kidney 293 cells as well as in rat pheochromocytoma PC12 cells. In both cell lines phosphorylation was highly sensitive to phosphatases, since okadaic acid markedly stabilized phosphate incorporation. Phosphoamino acid analysis revealed that phosphorylation occurred predominantly on serine. Using site-directed mutagenesis we have identified a major phosphorylation site at serine 129 within the C-terminal domain of alpha-synuclein. An additional site, which was phosphorylated less efficiently, was mapped to serine 87. The major phosphorylation site was located within a consensus recognition sequence of casein kinase 1 (CK-1). In vitro experiments and two-dimensional phosphopeptide mapping provided further evidence that serine 129 was phosphorylated by CK-1 and CK-2. Moreover, phosphorylation of serine 129 was reduced in vivo upon inhibition of CK-1 or CK-2. These data demonstrate that alpha-synuclein is constitutively phosphorylated within its C terminus and may indicate that the function of alpha-synuclein is regulated by phosphorylation/dephosphorylation.
Oh, S. O., J. H. Hong, et al. (2000). "Regulation of phospholipase D2 by H(2)O(2) in PC12 cells." J Neurochem 75(6): 2445-54.
Phospholipase D2 (PLD2) is expressed in brain and inhibited by synuclein, which is involved in Parkinson's and Alzheimer's diseases. However, the activation mechanism of PLD2 in neuronal cells has not been defined clearly. Hydrogen peroxide (H(2)O(2)) plays roles in the neurodegenerative diseases and also acts as a second messenger of various molecules such as nerve growth factor. To study regulation mechanisms of PLD2 by H(2)O(2) in neuronal cells, we have made stable PC12 cell lines expressing PLD2 (PLD2-PC12 cells). H(2)O(2) treatment stimulated PLD activity in PLD2-PC12 cells in a dose- and time-dependent manner. This activation was inhibited by the treatment with protein kinase C (PKC) inhibitors or by depletion of PKCalpha, -delta, and -epsilon. Phorbol ester markedly activated PLD2. Co-treatment with phorbol ester and H(2)O(2) did not show an additive effect. Chelation of extracellular calcium substantially blocked the H(2)O(2)-induced activation of PLD2. A calcium ionophore induced PLD2 activation in a PKC-dependent manner. Protein-tyrosine kinase inhibitors inhibited H(2)O(2)-induced PLD activation slightly. These data indicate that H(2)O(2) can activate PLD2 in PC12 cells and that this activation is largely dependent on PKC and Ca(2+) ions and minimally dependent on tyrosine phosphorylation.
Ninkina, N. N. and V. L. Bukhman (2000). "[Synucleins--to have or not to have]." Genetika 36(11): 1487-91.
Synucleins, a protein family little known even three years ago, became extremely popular after two discoveries. First, alpha-synuclein was found to be involved in etiology and pathogenesis of neurodegenerative disorders. Second, some newly discovered synucleins were found to participate in development and function of certain divisions of the nervous system and some other tissues, as well as in malignisation of breast tumors. It is now evident that synucleins are a fundamentally new group of proteins. Despite the striking similarity of their amino-acid sequences, they have diverse and multiple functions. An important challenge for biomedical science is to understand functions of sinucleins in normal cells and their role in pathology.
Neumann, M., S. Adler, et al. (2000). "Alpha-synuclein accumulation in a case of neurodegeneration with brain iron accumulation type 1 (NBIA-1, formerly Hallervorden-Spatz syndrome) with widespread cortical and brainstem-type Lewy bodies." Acta Neuropathol (Berl) 100(5): 568-74.
We studied a 27-year-old woman who died after a 6-year history of progressive dementia, dystonia, ataxia, apraxia, spasticity, choreoathetosis, visual and auditory hallucinations, and optic atrophy. Magnetic resonance imaging showed decreased intensity in the globus pallidus, substantia nigra, and dentate nuclei in T2-weighted images, supporting the clinical diagnosis of neurodegeneration with brain iron accumulation type 1 (NBIA-1; formerly known as Hallervorden-Spatz syndrome). At autopsy the brain showed mild frontotemporal atrophy and discoloration of the globus pallidus and the substantia nigra pars reticularis. Histologically, features typical of NBIA-1 were found including widespread axonal spheroids and large deposits of iron pigment in the discolored regions. Additionally, excessive numbers of Lewy bodies (LBs) were found throughout all examined brain stem and cortical regions. LBs of both types, as well as Lewy neurites in this case of NBIA-1, were strongly labeled by antibodies against alpha-synuclein. These findings give further evidence that accumulation of alpha-synuclein is generally associated with LB formation, i.e., in Parkinson's disease, dementia with Lewy bodies and NBIA-1. The case presented here is particularly notable for its high number of LBs in all areas of the cerebral cortex.
Nakamura, S., Y. Kawamoto, et al. (2000). "Expression of the endocytosis regulatory proteins Rab5 and Rabaptin-5 in glial cytoplasmic inclusions from brains with multiple system atrophy." Clin Neuropathol 19(2): 51-6.
BACKGROUND: Glial cytoplasmic inclusions (GCIs) occur specifically in oligodendrocytes in brains with multiple system atrophy (MSA). Oligodendrocytes in MSA appear to be functionally altered in their nature in terms of the occurrence of GCIs and aberrant expression of various proteins such as neuron specific protein, MAP2 or pre-synaptic protein, ct-synuclein. The present study examined whether or not aberrant expression of the endocytosis regulatory proteins Rab5 and Rabaptin-5 occcur in oligodendrocytes of brains with MSA. MATERIALS AND METHODS: We examined immunohistochemically the post-mortem brain tissues from 5 patients with MSA and 5 controls. Immunohistochemistry was done using monoclonal anti-Rab5 and anti-Rabaptin-5 antibodies based on ABC method. RESULTS: We have observed Rab5 and Rabaptin-5 immunoreactivity in the neuronal somata and axons of the controls, suggesting that Rab5 and Rabaptin-5 are involved in the regulation of the endocytosis in neurons of the human central nervous system. In the brain tissues from patients with MSA, we have found Rab5 and Rabaptin-5 immunoreactivity in GCIs. CONCLUSION: Rab5, in association with Rabaptin-5, has been demonstrated in the early endosome and regulates the endocytosis. Since Rab5 and Rabaptin-5 have been immunolocalized to neurons in the human brains, we propose that oligodendrocytes may ectopically express Rab5 and Rabaptin-5 in MSA. Thus, the oligodendrocytes in MSA brains appear to be functionally significantly altered, which may be associated with the formation of GCIs in the oligodendrocytes.
Murphy, D. D., S. M. Rueter, et al. (2000). "Synucleins are developmentally expressed, and alpha-synuclein regulates the size of the presynaptic vesicular pool in primary hippocampal neurons." J Neurosci 20(9): 3214-20.
alpha-, beta-, and gamma-Synuclein, a novel family of neuronal proteins, has become the focus of research interest because alpha-synuclein has been increasingly implicated in the pathogenesis of Parkinson's and Alzheimer's disease. However, the normal functions of the synucleins are still unknown. For this reason, we characterized alpha-, beta-, and gamma-synuclein expression in primary hippocampal neuronal cultures and showed that the onset of alpha- and beta-synuclein expression was delayed after synaptic development, suggesting that these synucleins may not be essential for synapse formation. In mature cultured primary neurons, alpha- and beta-synuclein colocalized almost exclusively with synaptophysin in the presynaptic terminal, whereas little gamma-synuclein was expressed at all. To assess the function of alpha-synuclein, we suppressed expression of this protein with antisense oligonucleotide technology. Morphometric ultrastructural analysis of the alpha-synuclein antisense oligonucleotide-treated cultures revealed a significant reduction in the distal pool of synaptic vesicles. These data suggest that one function of alpha-synuclein may be to regulate the size of distinct pools of synaptic vesicles in mature neurons.
Munoz, D. G. (2000). "[Neuropathology of frontotemporal dementia]." Neurologia 15 Suppl 1: 2-8.
The syndrome of progressive fronto-temporal dementia represents the clinical expression of several pathological processes, mostly degenerative, preferentially involving the frontal and temporal lobes. These processes include dementia with Pick bodies, cortico-basal degeneration, dementia with ITSNU (Inclusions Tau and Synuclein Negative, Ubiquitinated), also known as dementia of motorneuron disease type, dementia with basophilic inclusion bodies, and dementia lacking specific histopathology, and in addition all variants linked to mutations in the tau gene, located in chromosome 17. The term "Pick complex" encompasses these processes and their clinical manifestations, which in addition to fronto-temporal dementia include primary progressive aphasia and apraxic-motor syndromes. The pathologic processes are better discriminated by histopathology than distribution of atrophy, but the latter is the main determinant of the clinical presentation.
Mukaetova-Ladinska, E. B., F. Garcia-Siera, et al. (2000). "Staging of cytoskeletal and beta-amyloid changes in human isocortex reveals biphasic synaptic protein response during progression of Alzheimer's disease." Am J Pathol 157(2): 623-36.
We have examined the relationships between dementia, loss of synaptic proteins, changes in the cytoskeleton, and deposition of beta-amyloid plaques in the neocortex in a clinicopathologically staged epidemiological cohort using a combination of biochemical and morphometric techniques. We report that loss of synaptic proteins is a late-stage phenomenon, occurring only at Braak stages 5 and 6, or at moderate to severe clinical grades of dementia. Loss of synaptic proteins was seen only after the emergence of the full spectrum of tau and beta-amyloid pathology in the neocortex at stage 4, but not in the presence of beta-amyloid plaques alone. Contrary to previous studies, we report increases in the levels of synaptophysin, syntaxin, and SNAP-25 at stage 3 and of alpha-synuclein and MAP2 at stage 4. Minimal and mild clinical grades of dementia were associated with either unchanged or elevated levels of synaptic proteins in the neocortex. Progressive aggregation of paired helical filament (PHF)-tau protein could be detected biochemically from stage 2 onwards, and this was earliest change relative to the normal aging background defined by Braak stage 1 that we were able to detect in the neocortex. These results are consistent with the possibility that failure of axonal transport associated with early aggregation of tau protein elicits a transient adaptive synaptic response to partial de-afferentation that may be mediated by trophic factors. This early abnormality in cytoskeletal function may contribute directly to the earliest clinically detectable stages of dementia.
Mukaetova-Ladinska, E. B., J. Hurt, et al. (2000). "Alpha-synuclein inclusions in Alzheimer and Lewy body diseases." J Neuropathol Exp Neurol 59(5): 408-17.
Alpha-synuclein has assumed particular neuropathological interest in the light both of its identification as a non-beta-amyloid plaque constituent in Alzheimer disease (AD), and the recent association between dominant inheritance of Parkinson disease (PD) and 2 missense mutations at positions 30 and 53 of the synuclein protein. We report a systematic study of alpha-synuclein, tau, and ubiquitin immunoreactivity in representative neurodegenerative disorders of late life. The alpha-synuclein association with Lewy bodies is variable, peripheral, and is not stable with respect to proteases or acid treatment, whereas there is no association with Pick bodies. Stable patterns of immunoreactivity included neurites and a novel inclusion body. Although there is an overlap between the presence of Lewy bodies and stable alpha-synuclein immunoreactivity, this is seen only in the presence of concomitant neuropathological features of AD. The novel alpha-synuclein inclusion body identified in pyramidal cells of the medial temporal lobe in particular was found in AD and in the Lewy body variant of AD, and was associated neither with ubiquitin nor tau protein. The inclusion is therefore neither a Lewy body nor a PHF-core body, but may be confused with the Lewy body, particularly in the Lewy body variant of AD. Abnormal processing of alpha-synuclein leading to its deposition in the form of proteolytically stable deposits is a particular feature of the intermediate stages of AD.
McLean, P. J., S. Ribich, et al. (2000). "Subcellular localization of alpha-synuclein in primary neuronal cultures: effect of missense mutations." J Neural Transm Suppl(58): 53-63.
Numerous recent observations have implicated alpha-synuclein in the pathogenesis of several neurodegenerative diseases, including Parkinson's disease, Alzheimer's disease, dementia with Lewy bodies and multiple-system atrophy. Two missense mutations in the gene for alpha-synuclein have been identified in some cases of familial Parkinson's disease and it is thought that these may disrupt the normal structure of the protein and thus promote aggregation into Lewy body filaments. Here, we examine the subcellular localization of alpha-synuclein in primary cortical neurons maintained in a monolayer culture. The protein has widespread expression throughout neurons, including the nucleus, and has a discete localization in the neurites of more mature neurons, reminiscent of synaptic specializations. Interestingly, in a subpopulation of cortical neurons transfected at 13 days in vitro, we find that alpha-synuclein appears to aggregate into distinct punctate inclusions in the cytoplasm and proximal neurites. Unlike Lewy bodies, these structures are not ubiquitin positive. These regions of alpha-synuclein accumulation are observed following transfections with wild-type, Ala30Pro or Ala53Thr alpha-synuclein; neither mutation alters their frequency.
McLean, P. J., H. Kawamata, et al. (2000). "Membrane association and protein conformation of alpha-synuclein in intact neurons. Effect of Parkinson's disease-linked mutations." J Biol Chem 275(12): 8812-6.
Two missense mutations (Ala-30 --> Pro and Ala-53 --> Thr) in the gene encoding alpha-synuclein are associated with rare autosomal dominant forms of familial Parkinson's disease. In addition, alpha-synuclein is an abundant component of Lewy bodies in sporadic Parkinson's disease and diffuse Lewy body disease. However, the normal conformation of alpha-synuclein, its cellular localization in neurons, and the effects of the mutations remain to be determined. In the present study, we examine these questions using sensitive fluorescence resonance energy transfer techniques. Transient transfection of alpha-synuclein expression constructs into primary cortical neurons and counterstaining with the lipophilic fluorescent marker, DiI, demonstrates a close association between alpha-synuclein and cellular membranes. Both the N- and C-terminal regions of alpha-synuclein are tightly associated with membranes. A weak interaction also occurs between the N and C termini themselves. The Parkinson's disease-associated mutations have no effect on membrane interaction; however, the Ala-30 --> Pro mutation alters the three-dimensional conformation of alpha-synuclein, as measured by significantly increased fluorescence resonance energy transfer between the N and C termini.
Mattila, P. M., J. O. Rinne, et al. (2000). "Alpha-synuclein-immunoreactive cortical Lewy bodies are associated with cognitive impairment in Parkinson's disease." Acta Neuropathol (Berl) 100(3): 285-90.
Amygdala, hippocampus and six cortical gyri were examined for the Lewy body (LB) degeneration and Alzheimer's disease (AD) type changes in 45 patients with Parkinson's disease (PD). For detection of LBs, the brain areas were stained with an antibody against alpha-synuclein. The extent of neuropathological lesions was investigated in relation to cognitive dysfunction and apolipoprotein E (apoE) epsilon4 allele dosage. At least one cortical LB was found in 95% of cases (43/45). Furthermore, 40% of cases (18/45) had histological findings of definite AD (CERAD class C). Those PD cases with the apoE epsilon4 allele had a significantly greater number of cortical LBs than those without the apoE epsilon4 allele, but this was statistically significant only in precentral, angular and temporal gyri. The LB density correlated better with the number of plaques than with the density of tangles. The number of LBs in several cortical areas correlated significantly with the cognitive impairment. In stepwise linear regression analysis, the number of LBs in the cingulate gyrus and the amount of tangles in the temporal cortex remained statistically significant. When the CERAD class C was excluded, the correlation between cognitive decline and the number of LBs in cortical areas became even more pronounced. A stepwise linear regression analysis in these cases found the number of LBs in the frontal gyrus to be the statistically most significant predictor of cognitive impairment. This study shows, for the first time, that in PD, alpha-synuclein-positive cortical LBs are associated with cognitive impairment independent of AD-type pathology.
Masliah, E., E. Rockenstein, et al. (2000). "Dopaminergic loss and inclusion body formation in alpha-synuclein mice: implications for neurodegenerative disorders." Science 287(5456): 1265-9.
To elucidate the role of the synaptic protein alpha-synuclein in neurodegenerative disorders, transgenic mice expressing wild-type human alpha-synuclein were generated. Neuronal expression of human alpha-synuclein resulted in progressive accumulation of alpha-synuclein-and ubiquitin-immunoreactive inclusions in neurons in the neocortex, hippocampus, and substantia nigra. Ultrastructural analysis revealed both electron-dense intranuclear deposits and cytoplasmic inclusions. These alterations were associated with loss of dopaminergic terminals in the basal ganglia and with motor impairments. These results suggest that accumulation of wild-type alpha-synuclein may play a causal role in Parkinson's disease and related conditions.
Marui, W., E. Iseki, et al. (2000). "Occurrence of human alpha-synuclein immunoreactive neurons with neurofibrillary tangle formation in the limbic areas of patients with Alzheimer's disease." J Neurol Sci 174(2): 81-4.
We examined alpha-synuclein immunoreactivity in the brains from 23 patients with Alzheimer's disease (AD) and two patients with Down's syndrome. In ten of the 23 AD cases and both the two Down's syndrome cases, alpha-synuclein immunoreactivities were observed in the neurons of the limbic areas, predominantly of the amygdala. Nearly all alpha-synuclein-positive neurons had tau-positive neurofibrillary tangles (NFT) in the same neurons, and these consisted of intermingled-type and superimposed-type. By immunoelectron microscopy, the intermingled-type revealed aggregations of alpha-synuclein-positive filamentous components, which were in continuity with paired helical filaments (PHF), while the superimposed-type revealed accumulations of alpha-synuclein-positive non-filamentous components in PHF bundles. These findings suggest that alpha-synuclein can accumulate in PHF and form filamentous aggregations in neurons of the limbic areas in AD cases.
Martin, G. M. (2000). "Molecular mechanisms of late life dementias." Exp Gerontol 35(4): 439-43.
A brief overview of the molecular pathology of dementia of the Alzheimer type (DAT), frontotemporal dementias (FTD), and Lewy body dementias (LBD) is preceded by a discussion of the evolutionary biological basis for the types of gene action responsible for the emergence of late life dementias. The beta amyloid cascade theory of the pathogenesis of DAT still predominates, but possible upstream events are being explored. Some familial forms of FTD have been shown to result from dominant mutations in the microtubular associated protein tau. A key element in pathogenesis is a shift in the ratios of various isoforms. Rare forms of Parkinson disease have been associated with dominant mutations in alpha synuclein, a protein of probable importance for synaptic plasticity. Aberrations in the metabolism of this protein (which is found in Lewy body fibrillar material) may therefore be of importance to the genesis of some LBD cases.
Liu, J., M. J. Spence, et al. (2000). "Transcriptional suppression of synuclein gamma (SNCG) expression in human breast cancer cells by the growth inhibitory cytokine oncostatin M." Breast Cancer Res Treat 62(2): 99-107.
Previously, we have shown that synuclein gamma (SNCG), a member of the brain protein synuclein family, is highly expressed in human infiltrating breast carcinomas but not expressed in normal or benign breast tissues. The SNCG mRNA was also detected in several human breast cancer cell lines with the highest expression found in H3922, a cell line derived from an infiltrating ductal carcinoma. In this study, we show that expression of SNCG mRNA in H3922 cells is significantly decreased by treating cells with the cytokine oncostatin M (OM) who has a growth-inhibitory effect on these cells. A decrease in SNCG mRNA level can be detected as early as 30 min after OM addition. By 4 h OM treatment, the level of SNCG mRNA was decreased to 70% of control, and by 24 h the mRNA was below detectable level. Western blot analysis further demonstrated the suppression of SNCG protein expression by OM. The level of SNCG protein in H3922 cells was reduced more than 90% by OM after 2 days. Since OM-induced growth inhibition occurs after 3-4 days, the down-regulation of SNCG expression appears to proceed the effect of OM on cell growth. Additional experiments to measure the transcriptional rates of SNCG indicate that the observed OM-induced down-regulation of SNCG mRNA occurs mainly at the transcriptional level. In an attempt to examine the role of SNCG gene in the proliferation of breast cancer cells, SNCG cDNA was stably transfected into MCF-7 cells that do not express endogenous SNCG gene. Examination of cell growth under anchorage-dependent and anchorage-independent conditions demonstrates that over expression of SNCG gene significantly stimulated the growth of MCF-7 cells both in monolayer culture and in soft agar. These data together suggest that SNCG may play a role in cell proliferation.
Levey, A. I. (2000). "Molecules of the brain." Hosp Pract (Off Ed) 35(2): 41-8, 51-4.
Progress against a range of brain disorders is being sustained by the use of genetic research techniques to identify specific molecules involved in brain disease, and by the realization that the identified molecules may disclose novel therapeutic targets. Both strategies are illustrated by recent insights and interventions in Alzheimer's disease and Parkinson's disease.
Kruger, R., T. Muller, et al. (2000). "Involvement of alpha-synuclein in Parkinson's disease and other neurodegenerative disorders." J Neural Transm 107(1): 31-40.
A major step in the elucidation of the pathogenesis of neurodegenerative disorders was the identification of a mutation in the alpha-synuclein gene in autosomal dominant Parkinson's disease (PD). Alpha-synuclein is the main component of Lewy bodies (LB), the neuropathological hallmark of PD. Moreover, a fragment of alpha-synuclein (NAC) is the second major component of amyloid plaques in Alzheimer's disease (AD). Recent studies of other neurodegenerative disorders such as dementia with LB (DLB), multiple system atrophy (MSA) and amyotrophic lateral sclerosis (ALS) also revealed intracellular accumulations of alpha-synuclein in affected brain regions. This may indicate that these disorders partially share common pathogenic mechanisms. Recent data provide first insights into the physiological function of alpha-synuclein and support the concept of an essential role of alpha-synuclein in neurodegeneration. Increasing knowledge on the pathogenic molecular mechanisms of neurodegeneration and of the pathophysiological function of alpha-synuclein in particular may influence future development of therapeutic strategies in neurodegenerative disorders.
Kowall, N. W., P. Hantraye, et al. (2000). "MPTP induces alpha-synuclein aggregation in the substantia nigra of baboons." Neuroreport 11(1): 211-3.
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity reproduces many of the features of Parkinson's disease (PD). alpha-Synuclein has been identified as a prominent component of the Lewy body (LB), the pathological hallmark of PD. MPTP-treated primates have been reported to develop intraneuronal inclusions but not true Lewy bodies. We administered MPTP to baboons and used a monoclonal alpha-synuclein antibody to define the relationship between neuronal degeneration and alpha-synuclein immunoreactivity in the substantia nigra. MPTP-induced neuronal degeneration was associated with the redistribution of alpha-synuclein from its normal synaptic location to aggregates in degenerating neuronal cell bodies. alpha-Synuclein aggregation induced by MPTP models the early stages of Lewy body formation and may be a fundamental step in the evolution of neuronal degeneration in PD.
Kosaka, K. (2000). "Diffuse Lewy body disease." Neuropathology 20 Suppl: S73-8.
Diffuse Lewy body disease (DLBD) has been studied from various viewpoints and, although clinical diagnostic criteria for DLBD have been proposed, diagnosis remains difficult. DLBD has been reported to be the second most common form of dementia in the aged, following Alzheimer-type dementia. It has, however, been clinically under-diagnosed. Therefore, the search for diagnostic markers for DLBD must continue. Very recently, 'dementia with Lewy bodies' (DLB) was proposed as a generic term for various forms of dementia with Lewy bodies, including DLBD and similar disorders. Cortical Lewy bodies are the most important pathologic marker for diagnosis of DLBD. At present, however, the mechanism responsible for cortical Lewy body formation has yet to be disclosed.
Ko, L., N. D. Mehta, et al. (2000). "Sensitization of neuronal cells to oxidative stress with mutated human alpha-synuclein." J Neurochem 75(6): 2546-54.
Linkage of alpha-synuclein (alpha-SN) mutations to familial Parkinson's disease (PD) and presence of alpha-SN as a major constituent of Lewy body in both sporadic and familial PD implicate alpha-SN abnormality in PD pathogenesis. Here we demonstrate that overexpression of wild-type or mutant alpha-SN does not cause any deleterious effect on the growth or continued propagation of transfected human cells, but overproduction of mutant alpha-SN heightens their sensitivity to menadione-induced oxidative injury. Such enhanced vulnerability is more pronounced in neuronal transfectants than in their nonneuronal counterparts and is associated with increased production of reactive oxygen species. The data suggest that mutated alpha-SN, especially with an alanine-to-proline substitution at residue 30, sensitizes neuronal cells to oxidative damage.
Kitada, T. and Y. Mizuno (2000). "[Molecular pathogenesis of familial Parkinson's disease]." Nippon Rinsho 58(10): 2016-21.
Parkinson's disease is thought to be caused by an interaction of polygenic predisposition with environmental factors. In contrast, familial parkinsonism is caused by a single gene mutation. Four causative genes, i.e. alpha-synuclein, tau, UCH-L1 and parkin gene, have been already identified during the last three years. Their functions are being investigated from the points of over-production of abnormal proteins or abnormal proteolysis caused by them. Investigating and characterizing these causative genes may help us to explore the molecular mechanism of nigral neuronal cell death in sporadic type as well. In this paper, we review recent progress in molecular structures, pathogenesis, and animal models for these four genes.
Kitada, T., S. Asakawa, et al. (2000). "Progress in the clinical and molecular genetics of familial parkinsonism." Neurogenetics 2(4): 207-18.
Parkinson's disease (PD) is a neurodegenerative disease with clinical features resulting from deficiency of dopamine in the nigrostriatal system. Most PD cases are sporadic and the primary cause of the disease is still unknown. Recently, familial PD and parkinsonism have received much attention because these forms of the disease might provide clues to the genetic risk factors involved in the pathogenesis of idiopathic PD. To date, two causative genes, alpha-synuclein and the parkin gene, have been identified. alpha-Synuclein is involved in the pathogenesis of an autosomal dominant form of PD and constitutes a major component of the Lewy body, which is a pathological hallmark of idiopathic PD. In addition, mutations in the parkin gene have been identified as the cause of autosomal recessive juvenile parkinsonism (AR-JP). AR-JP manifests itself as a highly selective degeneration of the substantia nigra and the locus coeruleus, but without Lewy body formation. In addition to these two genes, four chromosomal loci have been linked to other forms of familial PD. Furthermore, there are a number of other pedigrees of familial PD in which linkage to known genetic loci has been excluded. Molecular cloning of these disease genes and elucidation of the function of their gene products will greatly contribute to our understanding of the pathogenesis of idiopathic PD.
Kim, T. D., H. J. Ryu, et al. (2000). "Thermal behavior of proteins: heat-resistant proteins and their heat-induced secondary structural changes." Biochemistry 39(48): 14839-46.
Most proteins are denatured by heat treatment, and the process is usually irreversible. However, some proteins, such as hyperthermophilic proteins are known to be stable even at the boiling temperature of water. We here describe a systematic investigation of thermal behavior of proteins by purifying and characterizing some heat-resistant proteins (HRPs) that are not aggregated upon heat treatment. Although most proteins were precipitated by boiling in a water bath, about 20 and 70 wt % of total proteins appeared to be heat-resistant in Jurkat T-cell lysates and human serum, respectively. We identified major HRPs from Jurkat T-cells and human serum by N-terminal amino acid sequencing and Western blot analysis. HRPs of 20 and 45 kDa (HRP20 and HRP45) were identified as alpha-synuclein and calreticulin, respectively, and HRPs of 60, 27, and 16 kDa (HRP60, HRP27, and HRP16) were identified as human serum fetuin, apolipoprotein A-I, and transthyretin, respectively. By a systematic investigation of the effect of heat on the secondary structure of the purified HRPs by circular dichroic spectroscopy, we observed four major types of thermal behavior, suggesting that the proteins could protect themselves through these pathways. Although our analysis is restricted to protein secondary structural changes, our data indicate that heat resistance of protein can be achieved in several different ways depending on the thermodynamic stability of native (N), unfolded (U), denatured (D), and intermediate (I) states.
Kiatipattanasakul, W., H. Nakayama, et al. (2000). "Abnormal neuronal and glial argyrophilic fibrillary structures in the brain of an aged albino cynomolgus monkey (Macaca fascicularis)." Acta Neuropathol (Berl) 100(5): 580-6.
An aged albino male cynomolgus monkey (Macaca fascicularis) more than 35 years old died after showing neurological signs including gait disturbance, trembling, drowsing tendency and a decrease in activity. Neuropathological examination revealed glial fibrillary tangles (GFTs) mainly distributed in the putamen, caudate nucleus, thalamic nuclei, substantia nigra, red nucleus, globus pallidus, trapezoid body, pyramid, pons and medulla oblongata of the brain, and neurofibrillary tangles (NFTs) in the thalamic nuclei. These structures were positively stained by the modified Gallyas-Braak (GB) method and immunostained for tau. The tau-positive argyrophilic GFTs were morphologically classified into four types, as in human cases, i.e., tufts of abnormal fibers (TAFs), thornshaped astrocytes (TSAs), glial coiled bodies (GCBs) and argyrophilic threads (ATs) depending on their GB profiles, and GCBs were the major structures in this case. Some of these structures were also immunoreactive for alpha-synuclein. The glial cells possessing the structures were negative for glial fibrillary acidic protein, a marker for astrocytes, indicating that the argyrophilic GFTs were present in oligodendroglia. In addition, marked neuronal loss and ubiquitin-positive spheroid bodies were observed in the substantia nigra and globus pallidus. According to the characteristic distribution of the argyrophilic structures in neurons and glial cells as well as clinical signs, the monkey might have suffered from a neurodegenerative disease such as progressive supranuclear palsy (PSP). This is the first report of the occurrence of a neurodegenerative disease in a nonhuman animal.
Kertesz, A., T. Kawarai, et al. (2000). "Familial frontotemporal dementia with ubiquitin-positive, tau-negative inclusions." Neurology 54(4): 818-27.
OBJECTIVE: To describe the clinical features, neuropathology, and genetic studies in a family with autosomal dominant frontotemporal dementia (FTD). BACKGROUND: Clinical Pick's disease, or FTD with parkinsonism, has been described in several families linked to chromosome 17 (FTDP-17). Most of these have shown tau protein mutations. The clinical and pathologic variations in these families resemble the spectrum of sporadic FTD or "Pick complex." METHODS: Clinical and behavioral analysis of the affected members with extensive histochemical and neuropathologic description of three cases, genetic analysis of three clinically affected members and seven at risk members to assess linkage to chromosome 17, and sequencing of the tau gene in two patients were performed. RESULTS: The clinical pattern shows a highly stereotypic disinhibition dementia with late extrapyramidal features, progressive mutism, and terminal dysphagia in three generations of affected individuals. Neuropathology showed frontotemporal atrophy, and microscopically tau- and synuclein-negative and ubiquitin-positive neuronal inclusions, in the background of superficial cortical spongiosis, neuronal loss, and gliosis. Tau expression was restricted to oligodendroglia. All exons and surrounding introns of the tau gene were sequenced, and no mutation or disease-related polymorphisms were detected in either of two affected pedigree members. CONCLUSION: This family with autosomal dominant frontotemporal dementia (FTD) shows no tau expression in neurons. The ubiquitin-positive, tau-negative inclusions have been described before in FTD with and without motor neuron disease, but not in a familial form. The clinical and some pathologic features are similar to those of several of the families included in descriptions of FTD with parkinsonism linked to chromosome 17, but the linkage to tau has been excluded. The defect in this family, however, could be functionally related to tau mutations.
Kawashima, M., S. O. Suzuki, et al. (2000). "alpha-Synuclein is expressed in a variety of brain tumors showing neuronal differentiation." Acta Neuropathol (Berl) 99(2): 154-60.
alpha-Synuclein is presynaptic nerve terminal protein and its immunoreactivity has been observed in such neurodegenerative structures as senile plaques of Alzheimer's disease or Lewy bodies of Parkinson's disease. The physiological role of alpha-synuclein is still unknown. It is speculated that alpha-synuclein may be expressed in brain tumors, especially in those showing neuronal differentiation. We examined the immunohistochemical localization of alpha-synuclein in 77 human brain tumors. alpha-Synuclein was widely distributed in the brain tumors showing neuronal differentiation. As a result, positive immunostaining for alpha-synuclein was observed in ganglioglioma, medulloblastoma, neuroblastoma, primitive neuroectodermal tumor, pineocytoma/pineoblastoma, and central neurocytoma. Compared with other neuronal markers, the positive ratio of alpha-synuclein was not as high as synaptophysin, microtubule-associated protein 2, neuron-specific enolase and tau, but it was higher than neurofilament and chromogranin A. The expression of synaptophysin was diffusely observed in the cytoplasm, cellular processes and nucleus in tumors showing neuronal differentiation; however, the expression of alpha-synuclein was predominantly observed in the cytoplasm of the tumors as well as in the cellular processes. On the other hand, non-neuronal brain tumors such as astrocytic tumors or meningiomas were totally negative for alpha-synuclein. In conclusion, the appearance of an alpha-synuclein-positive structure was not limited to neurodegenerative diseases, but could also be detected in neoplastic cells showing neuronal differentiation.
Kanda, S., J. F. Bishop, et al. (2000). "Enhanced vulnerability to oxidative stress by alpha-synuclein mutations and C-terminal truncation." Neuroscience 97(2): 279-84.
alpha-Synuclein is a key component of Lewy bodies found in the brains of patients with Parkinson's disease and two point mutations in this protein, Ala53Thr and Ala30Pro, are associated with rare familial forms of the disease. Several lines of evidence suggest the involvement of oxidative stress in the pathogenesis of nigral neuronal death in Parkinson's disease. In the present work we studied the effects of changes in the alpha-synuclein sequence on the susceptibility of cells to reactive oxygen species. Human dopaminergic neuroblastoma SH-SY5Y cells were stably transduced with various isoforms of alpha-synuclein and their survival following exposure to hydrogen peroxide or to the dopaminergic neurotoxin MPP(+) was assessed. Cells expressing the two point mutant isoforms of alpha-synuclein were significantly more vulnerable to oxidative stress, with the Ala53Thr engineered cells faring the worst. In addition, cells expressing C-terminally truncated alpha-synuclein, particularly the 1-120 residue protein, were more susceptible than control beta-galactosidase engineered cells.The present experiments indicate that point mutations and C-terminal truncation of alpha-synuclein exaggerate the susceptibility of dopaminergic cells to oxidative damage. Thus, these observations provide a pathogenetic link between alpha-synuclein aberrations and a putative cell death mechanism in Parkinson's disease.
Kahle, P. J., M. Neumann, et al. (2000). "Subcellular localization of wild-type and Parkinson's disease-associated mutant alpha -synuclein in human and transgenic mouse brain." J Neurosci 20(17): 6365-73.
Mutations in the alpha-synuclein (alphaSYN) gene are associated with rare cases of familial Parkinson's disease, and alphaSYN is a major component of Lewy bodies and Lewy neurites. Here we have investigated the localization of wild-type and mutant [A30P]alphaSYN as well as betaSYN at the cellular and subcellular level. Our direct comparative study demonstrates extensive synaptic colocalization of alphaSYN and betaSYN in human and mouse brain. In a sucrose gradient equilibrium centrifugation assay, a portion of betaSYN floated into lower density fractions, which also contained the synaptic vesicle marker synaptophysin. Likewise, wild-type and [A30P]alphaSYN were found in floating fractions. Subcellular fractionation of mouse brain revealed that both alphaSYN and betaSYN were present in synaptosomes. In contrast to synaptophysin, betaSYN and alphaSYN were recovered from the soluble fraction upon lysis of the synaptosomes. Synaptic colocalization of alphaSYN and betaSYN was directly visualized by confocal microscopy of double-stained human brain sections. The Parkinson's disease-associated human mutant [A30P]alphaSYN was found to colocalize with betaSYN and synaptophysin in synapses of transgenic mouse brain. However, in addition to their normal presynaptic localization, transgenic wild-type and [A30P]alphaSYN abnormally accumulated in neuronal cell bodies and neurites throughout the brain. Thus, mutant [A30P]alphaSYN does not fail to be transported to synapses, but its transgenic overexpression apparently leads to abnormal cellular accumulations.
Johnson, W. G. (2000). "Late-onset neurodegenerative diseases--the role of protein insolubility." J Anat 196 ( Pt 4): 609-16.
Recently, mutations of the alpha-synuclein gene were found to cause dominantly inherited Lewy-body Parkinson's disease (PD) and alpha-synuclein was identified as a major component of the Lewy body. However, the cause of the common form of PD, with a multifactorial rather than autosomal dominant inheritance pattern, remains unknown. Alpha-synuclein precipitates slowly and apparently spontaneously at high concentration in solution and the mutations that cause PD accelerate precipitation. Other dominantly inherited late-onset or adult-onset dominantly inherited neurodegenerative diseases are associated with precipitation of proteins. In Alzheimer disease, beta-amyloid and tau abnormalities are present and in prion disorders, prion proteins are found. In Huntington disease, a disorder with expanded CAG repeats, huntingtin precipitates occur. In dominantly inherited spinocerebellar ataxias, also expanded CAG repeat disorders, the corresponding ataxin protein precipitates are found. In multiple system atrophy, alpha-synuclein precipitates are encountered and in progressive supranuclear palsy, tau precipitates occur. In familial amyotrophic lateral sclerosis, a group of dominantly inherited disorders, SOD1 precipitates are found. Most of these disorders can involve the basal ganglia in some way. Since similar processes seem to affect neurons of adults or older individuals and since a relatively limited group of proteins seems to be involved, each producing a form of neurodegeneration, it is possible that certain common features are present that affect this group of proteins. Candidates include a conformational shift, as in prions, an abnormality of the ubiquitin-proteosome pathway, as seen in PD, an abnormality of a pathway preventing precipitation (e.g. chaperonins), or potentiation of a pathway promoting precipitation (e.g. gamma-glutamyl-transpeptidase) or apoptosis. Elucidation of the pathways causing this protein insolubilisation is the first step towards approaching prevention and reversal in these late-onset neurodegenerative diseases.
Jo, E., J. McLaurin, et al. (2000). "alpha-Synuclein membrane interactions and lipid specificity." J Biol Chem 275(44): 34328-34.
With the discovery of missense mutations (A53T and A30P) in alpha-synuclein (alpha-Syn) in several families with early onset familial Parkinson's disease, alpha-Syn aggregation and fibril formation have been thought to play a role in the pathogenesis of alpha-synucleinopathies, such as Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. As previous reports have suggested that alpha-Syn plays a role in lipid transport and synaptic membrane biogenesis, we investigated whether alpha-Syn binds to a specific lipid ligand using thin layer chromatography overlay and examined the changes in its secondary structure using circular dichroism spectroscopy. alpha-Syn was found to bind to acidic phospholipid vesicles and this binding was significantly augmented by the presence of phosphatidylethanolamine, a neutral phospholipid. We further examined the interaction of alpha-Syn with lipids by in situ atomic force microscopy. The association of soluble wild-type alpha-Syn with planar lipid bilayers resulted in extensive bilayer disruption and the formation of amorphous aggregates and small fibrils. The A53T mutant alpha-Syn disrupted the lipid bilayers in a similar fashion but at a slower rate. These results suggest that alpha-Syn membrane interactions are physiologically important and the lipid composition of the cellular membranes may affect these interactions in vivo.
Jensen, P. H., K. Islam, et al. (2000). "Microtubule-associated protein 1B is a component of cortical Lewy bodies and binds alpha-synuclein filaments." J Biol Chem 275(28): 21500-7.
Lewy bodies, neuropathological hallmarks of Parkinson's disease and dementia with Lewy bodies, comprise alpha-synuclein filaments and other less defined proteins. Characterization of Lewy body proteins that interact with alpha-synuclein may provide insight into the mechanism of Lewy body formation. Double immunofluorescence labeling and confocal microscopy revealed approximately 80% of cortical Lewy bodies contained microtubule-associated protein 1B (MAP-1B) that overlapped with alpha-synuclein. Lewy bodies were isolated using an immunomagnetic technique from brain tissue of patients dying with dementia with Lewy bodies. Lewy body proteins were resolved by polyacrylamide gel electrophoresis. Immunoblotting confirmed the presence of MAP-1B and alpha-synuclein in purified Lewy bodies. Direct binding studies revealed a high affinity interaction (IC(50) approximately 20 nm) between MAP-1B and alpha-synuclein. The MAP-1B-binding sites were mapped to the last 45 amino acids of the alpha-synuclein C terminus. MAP-1B also bound in vitro assembled alpha-synuclein fibrils. Thus, MAP-1B may be involved in the pathogenesis of Lewy bodies via its interaction with monomeric and fibrillar alpha-synuclein.
Jellinger, K. A. (2000). "Morphological substrates of mental dysfunction in Lewy body disease: an update." J Neural Transm Suppl 59: 185-212.
Mental dysfunction including cognitive, behavioural changes, mood disorders, and psychosis are increasingly recognized in patients with Parkinson's disease (PD) and related disorders. Their morphological correlates are complex due to multiple system degeneration. CNS changes contributing to cognitive changes in PD include 1. Dysfunction of subcorticocortical networks with neuron losses in a) the dopaminergic nigrostriatal loop, causing striato-(pre)frontal deafferentation and mesocortico-limbic system (medial substantia nigra, ventral tegmentum); b) noradrenergic (locus coeruleus), and serotonergic systems (dorsal raphe nuclei), c) cholinergic forebrain system (nucleus basalis of Meynert, etc), and d) specific nuclei of amygdala and limbic system (thalamic nuclei, hippocampus); 2. Limbic and/or cortical Lewy body and Alzheimer type pathologies with loss of neurons and synapses, 3. Combination of subcortical, cortical, and other pathologies. In general, degeneration of subcortical and striato-frontal networks causes cognitive, executive, behavioural, and mood disorders but less severe dementia than cortical changes which, when present in sufficient numbers, are important factors for overt dementia. In PD, cortical tau pathology with similar or differential patterns than in Alzheimer disease (AD) shows significant linear correlation with cognitive decline. In dementia with Lewy bodies (DLB), the second most frequent cause of dementia in the elderly, cortical Lewy bodies (LB) may or may not be associated with amyloid plaques and neuritic AD lesions. They predominantly affect the limbic system with less frequent isocortical Braak stages, whereas the cholinergic forebrain system is more severely affected than in AD. Both neuritic degeneration in limbic system in PD and DLB and the density of cortical synapse markers correlate with neuritic AD pathology and less with cortical LB counts. Apolipoprotein E epsilon4 allele frequency may represent a common genetic background for both AD and LB pathologies but there are different proportions of plaques between DLB (less Abeta1-40) and AD (more frequent Abeta1-40). Familial parkinsonism with dementia, linked to chromosome 17 (frontotemporal dementia with Parkinsonism (FTDP-17), and other tauopathies pathologically resembling PD plus AD, are often related to mutations of the tau gene, whereas familial PD with alpha-synuclein and Parkin mutations usually show no cognitive impairment. Mood disorders, in particular depression, and psychotic complications in both PD and DLB are related to complex involvement of noradrenergic and serotonergic systems, not confirmed in AD with depression, and both the prefrontal and limbic dopaminergic systems. The specific contributions of cortical and subcortical pathologies to mental dysfunction in PD and related disorders, their relationship to AD, and their genetic and aetiological backgrounds await further elucidation.
Jellinger, K. A. (2000). "Cell death mechanisms in Parkinson's disease." J Neural Transm 107(1): 1-29.
OBJECTIVE: While the causes of neuronal death in Parkinson's disease (PD) and other neurodegenerative disorders are still unknown, several mechanisms are under discussion: programmed vs. passive cell death (apoptosis vs. necrosis), mainly based on conflicting results on the rare presence or absence of DNA fragmentation in substantia nigra neurons using the in situ DNA-labeling (TUNEL) method. DESIGN/METHODS: In 4 cases of Parkinson's disease (PD), 2 cases of Dementia with Lewy bodies (DLB) and 3 age-matched controls, the TUNEL/ISEL method was used to detect DNA fragmentation in substantia nigra locus coeruleus and cerebral cortex [method by Gold et al. (1994)]. In addition, immunohistochemistry was performed for an array of apoptosis-related proteins, i.e. the recently described apoptosis specific protein cJun/AP1 (ASP), the proto-oncogenes c-Jun, c-Jun AP1, Bcl2, Bax, Bcl-x, p53, CD 95 (Fas/Apo-1), activated caspase 3, several heat shock proteins (alpha-B crystallin, ubiquitin), and alpha-synuclein. RESULTS: None of the cases of PD, DLB, and controls showed convincing TUNEL-positivity nor morphologic signs of apoptosis in nigral, locus coeruleus or cortical neurons with or without Lewy bodies but variable numbers of TUNEL-positive astrocytes and microglial cells in substantia nigra of PD and DLB. There were no significant differences in the expression of c-Jun, ASP, Bcl-2, Bax, and Bcl-x in substantia nigra neurons between PD, DLB, and controls nor between cortical and subcortical neurons with and without Lewy bodies. No expression of p53, and activated caspase 3, or any of the examined stress proteins was seen in neurons, while reactive astroglia and microglia were decorated by antibodies to Bcl-2, Bax, alpha-B-crystallin and less, to Bcl-x and caspase 3. Lewy bodies, dystrophic neurites and axonal spheroids, all being negative for the applied apoptosis regulating proteins, showed strong expression of the examined stress proteins and of alpha-synuclein. CONCLUSIONS: These findings which are in line with previous results in Alzheimer's disease (Stadelmann et al., 1998) and Parkinson's disease (Banati et al., 1999) suggest that mechanisms distinct from classical apoptosis play a central role in the pathogenesis of PD and related neurodegenerative diseases. Further studies are warranted to elucidate the intracellular cascade of events leading to cell death in these disorders showing slow progression over many years.
Jaros, E. and D. J. Burn (2000). "The pathogenesis of multiple system atrophy: past, present, and future." Mov Disord 15(5): 784-8.
Multiple system atrophy is a sporadic, adult-onset neurodegenerative disease of unknown etiology. The condition may be unique among neurodegenerative diseases by the prominent, if not primary, role played by the oligodendroglial cell in the pathogenetic process. Recent developments in our understanding of multiple system atrophy have included the detection of glial cytoplasmic inclusions and alpha-synuclein accumulation in these inclusions. The latter finding links multiple system atrophy as an "alpha-synucleinopathy" to Parkinson's disease and dementia with Lewy bodies. This article reviews recent important findings of potential relevance to the pathogenesis of multiple system atrophy. We also speculate on areas in which further advances may be made to progress our understanding of this devastating condition.
Iwai, A. (2000). "Properties of NACP/alpha-synuclein and its role in Alzheimer's disease." Biochim Biophys Acta 1502(1): 95-109.
The precursor of the non-amyloid beta/A4 protein (non-Abeta) component of Alzheimer's disease amyloid (NACP)/alpha-synuclein is the human homologue of alpha-synuclein, a member of a protein family which includes alpha-, beta- and gamma-synuclein. This protein is thought to be involved in neuronal plasticity because of its unique expression, mainly in the telencephalon during maturation. Consequently, disarrangement of NACP/alpha-synuclein might disrupt synaptic activity, resulting in memory disturbance. Previous studies have shown that damage to synaptic terminals is closely associated with global cognitive impairment and is an early event in the pathogenesis of Alzheimer's disease. Although the relationship between synaptic damage and amyloidogenesis is not clear, some proteins at the synaptic site have been implicated in both neuronal alteration and amyloid formation. Indeed, abnormal accumulation of both NACP/alpha-synuclein and Abeta precursor protein occurs at synapses of Alzheimer's patients. Other evidence suggests that NACP/alpha-synuclein is a component of the Lewy bodies found in patients with Parkinson's disease or dementia with Lewy bodies, and that a point mutation in this protein may be the cause of familial Parkinson's disease. Consequently, abnormal transport, metabolism or function of NACP/alpha-synuclein appears to impair synaptic function, which induces, at least in part, neuronal degeneration in several neurodegenerative diseases.
Iseki, E., W. Marui, et al. (2000). "Accumulation of human alpha-synuclein in different cytoskeletons in Lewy bodies in brains of dementia with Lewy bodies." Neurosci Lett 290(1): 41-4.
We investigated the origin of alpha-synuclein-immunoreactive components in Lewy bodies (LB) in brains of dementia with Lewy bodies (DLB) using immunohistochemistry and immunoelectron microscopy with anti-alpha-synuclein antibodies and anti-cytoskeleton antibodies. alpha-Synuclein-positive LB light microscopically consisted of phosphorylated neurofilament (PN)-positive LB, tubulin-positive LB and LB that were negative for both stains. Immunoelectron microscopically, PN-positive LB were composed of PN-positive and alpha-synuclein-positive filamentous components, suggesting that these filamentous components originate from neurofilaments with partially reduced immunoreactivity and alpha-synuclein accumulation. However, tubulin-positive LB were composed of tubulin-positive and alpha-synuclein-positive tubular components, suggesting that these tubular components originate from microtubules with diffusely reduced immunoreactivity and alpha-synuclein accumulation. The results of the present study suggest that alpha-synuclein accumulates in different cytoskeletons in the LB in DLB brains presumably due to a blockage of axonal transport.
Iseki, E., W. Marui, et al. (2000). "Degeneration process of Lewy bodies in the brains of patients with dementia with Lewy bodies using alpha-synuclein-immunohistochemistry." Neurosci Lett 286(1): 69-73.
We investigated the degeneration process of Lewy bodies (LB) in the brains of dementia with Lewy bodies, using alpha-synuclein-immunohistochemistry. Intracellular LB, LB-related neurites and some extracellular LB were positively immunostained with anti-alpha-synuclein antibodies. Concentric LB-bearing neurons had no microglial involvement, while degenerated neurons with ill-defined LB displayed intense microglial involvement. The late stage of extracellular LB were immunoelectron-microscopically composed of loose aggregates of filamentous components with lost alpha-synuclein-immunoreactivity and penetrated astroglial processes. These findings suggest that microglias are involved during the stages from degenerated LB-bearing neurons to extracellular LB, while astroglias are involved during the stage of extracellular LB. Some intracellular LB were positive for anti-C3d and -C4d antibodies, suggesting that the classical complement pathway is activated in degenerated LB-bearing neurons, inducing microglial activation and neuronal death.
Huynh, D. P., D. R. Scoles, et al. (2000). "Parkin is associated with actin filaments in neuronal and nonneural cells." Ann Neurol 48(5): 737-44.
Inactivating mutations of the gene encoding parkin are responsible for autosomal recessive juvenile parkinsonism (AR-JP). However, little information is known about the function and distribution of parkin. We generated antibodies to two different peptides of parkin. By Western blot analysis and immunohistochemistry, we found that parkin is a 50-kd protein that is expressed in neuronal processes and cytoplasm of selected neurons in the basal ganglia, midbrain, cerebellum, and cerebral cortex. Unlike ubiquitin and alpha-synuclein, parkin labeling was not found in Lewy bodies of four sporadic Parkinson disease brains. Parkin was colocalized with actin filaments but not with microtubules in COS1 kidney cells and nerve growth factor-induced PC12 neurons. These results point to the importance of the cytoskeleton and associated proteins in neurodegeneration.
Hurtig, H. I., J. Q. Trojanowski, et al. (2000). "Alpha-synuclein cortical Lewy bodies correlate with dementia in Parkinson's disease." Neurology 54(10): 1916-21.
BACKGROUND: Dementia is a frequent complication of idiopathic parkinsonism or PD, usually occurring later in the protracted course of the illness. The primary site of neuropathologic change in PD is the substantia nigra, but the neuropathologic and molecular basis of dementia in PD is less clear. Although Alzheimer's pathology has been a frequent finding, recent advances in immunostaining of alpha-synuclein have suggested the possible importance of cortical Lewy bodies (CLBs) in the brains of demented patients with PD. METHODS: The brains of 22 demented and 20 nondemented patients with a clinical and neuropathologic diagnosis of PD were evaluated with standard neuropathologic techniques. In addition, CLBs and dystrophic neurites were identified immunohistochemically with antibodies specific for alpha-synuclein and ubiquitin; plaques and tangles were identified by staining with thioflavine S. Associations between dementia status and pathologic markers were tested with logistic regression. RESULTS: CLBs positive for alpha-synuclein are highly sensitive (91%) and specific (90%) neuropathologic markers of dementia in PD and slightly more sensitive than ubiquitin-positive CLBs. They are better indicators of dementia than neurofibrillary tangles, amyloid plaques, or dystrophic neurites. CONCLUSION: CLBs detected by alpha-synuclein antibodies in patients with PD are a more sensitive and specific correlate of dementia than the presence of Alzheimer's pathology, which was present in a minority of the cases in this series.
Hu, C. J., S. M. Sung, et al. (2000). "Polymorphisms of the parkin gene in sporadic Parkinson's disease among Chinese in Taiwan." Eur Neurol 44(2): 90-3.
The role of genetics in Parkinson's disease (PD), previously controversial, is now documented by several studies. A major breakthrough has been the discovery of two single-gene defects in familial PD. A single base pair change at position 209 from G to A (G209A) in the fourth exon of the alpha-synuclein gene has been identified in cases of autosomal dominant familial PD. Mutations in the Parkin gene can induce autosomal recessive juvenile parkinsonism. A polymorphism of R/W366 in the Parkin gene was found to be associated with a protective factor for sporadic PD. We surveyed the polymorphisms of the Parkin gene, including S/N167, R/W366 and V/L380, in 92 cases of sporadic PD and 98 nonaffected individuals in Taiwanese Chinese. The allele frequencies of these polymorphisms are not significantly different between PD and nonaffected controls. We conclude that polymorphisms of the Parkin gene, S/N167, R/W366, V/L380, are not genetic factors for sporadic PD among Chinese in Taiwan.
Hsu, L. J., Y. Sagara, et al. (2000). "alpha-synuclein promotes mitochondrial deficit and oxidative stress." Am J Pathol 157(2): 401-10.
Abnormal accumulation of the presynaptic protein alpha-synuclein has recently been implicated in the pathogenesis of Alzheimer's and Parkinson's diseases. Because neurodegeneration in these conditions might be associated with mitochondrial dysfunction and oxidative stress, the effects of alpha-synuclein were investigated in a hypothalamic neuronal cell line (GT1-7). alpha-Synuclein overexpression in these cells resulted in formation of alpha-synuclein-immunopositive inclusion-like structures and mitochondrial alterations accompanied by increased levels of free radicals and decreased secretion of gonadotropin-releasing hormone. These alterations were ameliorated by pretreatment with anti-oxidants such as vitamin E. Taken together these results suggest that abnormal accumulation of alpha-synuclein could lead to mitochondrial alterations that may result in oxidative stress and, eventually, cell death.
Higuchi, M., M. Tashiro, et al. (2000). "Glucose hypometabolism and neuropathological correlates in brains of dementia with Lewy bodies." Exp Neurol 162(2): 247-56.
Cerebral glucose metabolism using positron emission tomography (PET) with (18)F-fluorodeoxyglucose was examined in 11 patients with probable Alzheimer's disease (AD), 6 patients with probable, and 1 patient with autopsy-confirmed dementia with Lewy bodies (DLB) as well as in 10 age-matched normal control subjects. Among widespread cortical regions showing glucose hypometabolism in the DLB group, the metabolic reduction was most pronounced in the visual association cortex compared to that in the AD group. Using a metabolic ratio of 0.92 in the visual association cortex as a cutoff (mean-2 SD of normal control subjects), DLB could be distinguished from AD with a sensitivity of 86% and a specificity of 91%. In contrast, apolipoprotein E4 allele frequency and cerebrospinal fluid tau levels did not differ significantly between the two groups. In order to further dissect out neuropathological correlates of the dysfunctional occipital lobe, postmortem brains from 19 patients with AD and 17 with DLB as well as 11 brains from normal controls were examined. A distinct and extensive spongiform change with coexisting gliosis was variably noted throughout cerebral white matter with relative sparing of gray matter in DLB. Notably, the white matter spongiform change and gliosis was most prominently and consistently found in the occipital region of DLB, and the severity of the spongiform change in each brain region generally paralleled to the regional difference in reduced glucose metabolism between the living AD and DLB patients. These findings suggest that (1) among several potential antemortem biomarkers in the diagnosis of DLB, measures of the glucose metabolism in the occipital cortex may be an informative diagnostic aid to distinguish DLB from AD; and (2) a pathological process that generates widespread spongiform change and gliosis in long projection fibers may contribute, at least in part, to the characteristic imaging features of DLB.
Hayashi, S |
