Cadet, J. L. (2001). "Molecular neurotoxicological models of Parkinsonism: focus on genetic manipulation of mice." 8(2): 85-90.
Parkinson's disease is a neurodegenerative disorder that affects mainly the nigrostriatal dopaminergic system in humans. Several propositions have been put forward to explain the cellular and molecular pathobiology of this syndrome. Initial attempts were made through the use of various agents to manipulate the deleterious effects of toxins that destroy dopaminergic cells both in vitro and in vivo. These studies led to the idea that oxidative stress is an important factor in killing these cells. More recent attempts have made use of genetically modified mice to eliminate or over-express genes of interest. These experiments have suggested that the destruction of dopaminergic cells might be the result of the convergence of dependent and independent molecular pathways and that trigger cellular events might lead to the demise of these dopaminergic cells.

Callizot, N., J. L. Guenet, et al. (2001). "The frissonnant mutant mouse, a model of dopamino-sensitive, inherited motor syndrome." Neurobiol Dis 8(3): 447-58.
The frissonnant (fri) mutation is an autosomic recessive mutation which spontaneously appeared in the stock of C3H mice. fri mutant mice have locomotor instability and rapid tremor. Since tremor ceases when mutant mice have sleep or are anaesthetized, and because of their obvious stereotyped motor behavior, these mice could represent an inherited Parkinsonian syndrome. We show here that the fri/fri mouse fulfills two out of the three criteria required to validate an experimental model of human disease, that is isomorphism, homology and predictivity. Indeed, fri/fri mice present an important motor deficit accompanying visible tremor and stereotypies. They display some memory deficits as in human Parkinson's desease. l-Dopa and apomorphine (dopaminergic agonists), ropinirole (selective D2 agonist), and selegiline (an monoamino-oxidase B [MAO-B] inhibitor) improve their clinical status. However, neither anatomopathological evidence of nigrostriatal lesion, nor decrease in tyrosine hydroxylase production could be seen. Copyright 2001 Academic Press.

Carvey, P. M., Z. D. Ling, et al. (2001). "A clonal line of mesencephalic progenitor cells converted to dopamine neurons by hematopoietic cytokines: a source of cells for transplantation in Parkinson's disease." Exp Neurol 171(1): 98-108.
Neural progenitor cells potentially provide a limitless, on-demand source of cells for grafting into patients with Parkinson's disease (PD) if the signals needed to control their conversion into dopamine (DA) neurons could be identified. We have recently shown that cytokines which instruct cell division and differentiation within the hematopoeitic system may provide similar functions in the central nervous system. We have shown that mitotic progenitor cells can be isolated from embryonic rat mesencephalon and that these cells respond to a combination of interleukin-1, interleukin-11, leukemia inhibitory factor, and glial cell line-derived neurotrophic factor yielding a tyrosine hydroxylase-immunoreactive (THir) phenotype in 20-25% of total cells. In the present study, 24 clonal cell lines derived from single cells of mesencephalic proliferation spheres were examined for their response to the cytokine mixture. The clone yielding the highest percentage of THir neurons (98%) was selected for further study. This clone expressed several phenotypic characteristics of DA neurons and expression of Nurr1. The response to cytokines was stable for several passages and after cryopreservation for several months. When grafted into the striatum of DA-depleted rats, these cells attenuated rotational asymmetry to the same extent as freshly harvested embryonic DA neurons. These data demonstrate that mesencephalic progenitor cells can be clonally expanded in culture and differentiated in the presence of hematopoietic cytokines to yield enriched populations of DA neurons. When transplanted, these cells provide significant functional benefit in the rat model of PD.

Casali, C., V. Bonifati, et al. (2001). "Mitochondrial myopathy, parkinsonism, and multiple mtDNA deletions in a Sephardic Jewish family." Neurology 56(6): 802-5.
The authors describe a family of Sephardic Jews with progressive external ophthalmoparesis, skeletal muscle weakness, and parkinsonism. Autosomal recessive inheritance was suggested by many consanguineous marriages, although a dominant disorder could not be excluded. No linkage to known progressive external ophthalmoparesis locus was found. The presence of cytochrome c oxidase-negative ragged-red fibers, biochemically reduced respiratory chain complexes, and multiple mitochondrial DNA deletions in muscle biopsies from four patients suggested a new mitochondrial disorder of intergenomic communication.

Chaudhuri, K. R. (2001). "Autonomic dysfunction in movement disorders." Curr Opin Neurol 14(4): 505-11.
Dysfunction of the autonomic nervous system is an under-recognised but important aspect of the aetiological and clinical manifestation of primary degenerative dysautonomias such as multiple system atrophy (MSA) and Parkinson's disease (PD). Although the clinical presentation of dysautonomia in these two disorders may overlap, yet pathological and in vivo imaging studies suggest considerable differences. Functional imaging studies suggest that selective cardiac sympathetic denervation may occur early in PD but not in other parkinsonian syndromes. The clinical implication of this apparently disease specific peripheral dysautonomia is unknown and would be the subject of much interest in future years. Dysautonomia in degenerative disorders also affect respiration, genitourinary function and sleep. Sleep related disorders such as rapid eye movement behaviour disorder and urinary voiding dysfunction appear to precede the development of PD related symptoms while patients with sporadic ataxia have been shown to progress to develop MSA. Dysautonomia has also been recognised in other movement disorders, examples being the combination of dystonia and complex regional pain syndrome with elevated HLA-DR13 and late onset Huntington's disease presenting with dominant parkinsonism and minimal chorea. These studies have helped progress in various diagnostic and management parameters in relation to autonomic dysfunction and movement disorders.

Chen, J. F., K. Xu, et al. (2001). "Neuroprotection by caffeine and A(2A) adenosine receptor inactivation in a model of Parkinson's disease." J Neurosci 21(10): RC143.
Recent epidemiological studies have established an association between the common consumption of coffee or other caffeinated beverages and a reduced risk of developing Parkinson's disease (PD). To explore the possibility that caffeine helps prevent the dopaminergic deficits characteristic of PD, we investigated the effects of caffeine and the adenosine receptor subtypes through which it may act in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxin model of PD. Caffeine, at doses comparable to those of typical human exposure, attenuated MPTP-induced loss of striatal dopamine and dopamine transporter binding sites. The effects of caffeine were mimicked by several A(2A) antagonists (7-(2-phenylethyl)-5-amino-2-(2-furyl)-pyrazolo-[4,3-e]-1,2,4-triazolo[1,5 -c]pyrimidine (SCH 58261), 3,7-dimethyl-1-propargylxanthine, and (E)-1,3-diethyl-8 (KW-6002)-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-purine-2,6-dione) (KW-6002) and by genetic inactivation of the A(2A) receptor, but not by A(1) receptor blockade with 8-cyclopentyl-1,3-dipropylxanthine, suggesting that caffeine attenuates MPTP toxicity by A(2A) receptor blockade. These data establish a potential neural basis for the inverse association of caffeine with the development of PD, and they enhance the potential of A(2A) antagonists as a novel treatment for this neurodegenerative disease.

Chen, C. H., C. C. Hung, et al. (2001). "Debrisoquine 4-hydroxylase (CYP2D6) genetic polymorphisms and susceptibility to schizophrenia in Chinese patients from Taiwan." Psychiatr Genet 11(3): 153-5.
Debrisoquine 4-hydroxylase (CYP2D6) is one of the cytochrome P450 enzyme families that metabolize many compounds. Polymorphic activities of debrisoquine 4-hydroxylase were suggested to be associated with some complex diseases, such as cancer and Parkinson's disease. Schizophrenia is also a complex disorder, and hence we are interested in understanding if the CYP2D6 gene is a susceptibility gene for schizophrenia in Chinese. We determined the genotype and allele frequencies of four molecular variants of CYP2D6 gene (i.e. 188C/T, 1934G/A, 2938C/T and 4268C/G) in 162 Chinese schizophrenic patients and 94 non-psychotic control subjects from Taiwan. No significant differences of allele or genotype frequencies of three polymorphisms (i.e. 188T/C, 2938C/T and 4268C/G) were detected between patients and control subjects. The 1934A allele, which accounts for the majority of poor metabolizers in Caucasians, was not detected in either patients or control subjects, indicating that the 1934A allele is very rare in Chinese. Our data suggest that the CYP2D6 gene may not be a susceptibility gene for schizophrenia in Chinese schizophrenic patients.

Chung, K. K., Y. Zhang, et al. (2001). "Parkin ubiquitinates the alpha-synuclein-interacting protein, synphilin-1: implications for Lewy-body formation in Parkinson disease." Nat Med 7(10): 1144-50.
Parkinson disease is a common neurodegenerative disorder characterized by the loss of dopaminergic neurons and the presence of intracytoplasmic-ubiquitinated inclusions (Lewy bodies). Mutations in alpha-synuclein (A53T, A30P) and parkin cause familial Parkinson disease. Both these proteins are found in Lewy bodies. The absence of Lewy bodies in patients with parkin mutations suggests that parkin might be required for the formation of Lewy bodies. Here we show that parkin interacts with and ubiquitinates the alpha-synuclein-interacting protein, synphilin-1. Co-expression of alpha-synuclein, synphilin-1 and parkin result in the formation of Lewy-body-like ubiquitin-positive cytosolic inclusions. We further show that familial-linked mutations in parkin disrupt the ubiquitination of synphilin-1 and the formation of the ubiquitin-positive inclusions. These results provide a molecular basis for the ubiquitination of Lewy-body-associated proteins and link parkin and alpha-synuclein in a common pathogenic mechanism through their interaction with synphilin-1.

Ciechanover, A. (2001). "Linking ubiquitin, parkin and synphilin-1." Nat Med 7(10): 1108-9.

Clostre, F. (2001). "[Mitochondria: recent pathophysiological discoveries and new therapeutic perspectives]." Ann Pharm Fr 59(1): 3-21.
Until about a decade ago, few researchers in clinical or evolutionary biology paid much attention to mitochondria. But over the years, as technological advances in molecular biology made nuclear functions more accessible to them, interest in mitochondria began to revive. First, geneticists started tracing certain rare inherited disorders to mutations in the mitochondria's circular genome. More recently, other researchers have speculated that mitochondria might contribute to aging, either by releasing tissue-damaging reactive oxygen molecules or by impairing and depriving the cell of the energy it needs to function. One the most important recent developments has been the recognition that mitochondria play a central role in the regulation of programmed cell death, or apoptosis. Now, we know that mitochondria play a decisive role in life-death decisions for the cell and may choose between the apoptotic and necrotic pathways. Mitochondria can trigger cell death in a number of ways: by disrupting electron transport and energy metabolism, by activating the mitochondrial permeability transition, by releasing and/or activating proteins that mediate apoptosis. Any or all of these mechanisms may help to explain how mitochondrial defects contribute to the pathogenesis of neuronal death or dysfunction in ischemia/reperfusion injury as well as in human degenerative diseases including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and Huntington's disease. This has opened up new avenues for understanding the pathogenesis of neurodegeneration and may lead to new and more effective therapeutic approaches to these diseases.

Cole, N. B., D. D. Murphy, et al. (2001). "Lipid droplet binding and oligomerization properties of the Parkinson's disease protein alpha-synuclein." J Biol Chem.
alpha-Synuclein is a major component of the fibrillary lesion known as Lewy bodies (LBs) and Lewy neurites (LNs) that are the pathologic hallmarks of Parkinson's disease (PD). In addition, point mutations in the alpha-synuclein gene implicate alpha-synuclein dysfunction in the pathology of inherited forms of PD. alpha-Synuclein is a member of a family of proteins found primarily in the brain and is concentrated within presynaptic terminals. Here, we address the localization and membrane binding characteristics of wild type and PD mutants of alpha synuclein in cultured cells. In cells treated with high concentrations of fatty acids, wild type alpha-synuclein accumulated on phospholipid monolayers surrounding triglyceride-rich lipid droplets, and was able to protect stored triglycerides from hydrolysis. PD mutant synucleins showed variable distributions on lipid droplets and were less effective in regulating triglyceride turnover. Chemical crosslinking demonstrated that synuclein formed small oligomers within cells, primarily dimers and trimers, that preferentially associated with lipid droplets and cell membranes. Our results suggest that the initial phases of synuclein aggregation may occur on the surfaces of membranes, and that pathological conditions that induce crosslinking of synuclein may enhance the propensity for subsequent synuclein aggregation.

Conn, K. J., M. D. Ullman, et al. (2001). "Decreased expression of the NADH:ubiquinone oxidoreductase (complex I) subunit 4 in 1-methyl-4-phenylpyridinium -treated human neuroblastoma SH-SY5Y cells." Neurosci Lett 306(3): 145-8.
Oxidative stress and mitochondrial dysfunction have been implicated in Parkinson's disease (PD) pathology. NADH:ubiquinone oxidoreductase (complex I) (EC 1.6.99.3) enzyme activity is aberrant in both PD and 1-methyl-4-phenylpyridinium (MPP(+)) models of PD. Reverse transcription polymerase chain reaction of RNA isolated from MPP(+)-treated human neuroblastoma SH-SY5Y cells identified changes in steady-state mRNA levels of the mitochondrial transcript for subunit 4 of complex I (ND4). Expression of ND4 decreased to nearly 50% after 72 h of MPP(+) (1 mM) exposure. The expression of other mitochondrial transcripts did not change significantly under the same conditions. Pre-incubation of cells with the free-radical spin-trap, N-tert-butyl-alpha-(2-sulfophenyl)-nitrone prior to MPP(+) exposure, prevented decreases in cell viability and ND4 expression. This suggests that functional defects in complex I enzyme activity in PD and MPP(+) toxicity may result from changes in steady-state mRNA levels and that free radicals may be important in this process.

Connor, B., D. A. Kozlowski, et al. (2001). "Glial cell line-derived neurotrophic factor (GDNF) gene delivery protects dopaminergic terminals from degeneration." Exp Neurol 169(1): 83-95.
Previously, we observed that injection of an adenoviral (Ad) vector expressing glial cell line-derived neurotrophic factor (GDNF) into the striatum, but not the substantia nigra (SN), prior to a partial 6-OHDA lesion protects dopaminergic (DA) neuronal function and prevents the development of behavioral impairment in the aged rat. This suggests that striatal injection of AdGDNF maintains nigrostriatal function either by protecting DA terminals or by stimulating axonal sprouting to the denervated striatum. To distinguish between these possible mechanisms, the present study examines the effect of GDNF gene delivery on molecular markers of DA terminals and neuronal sprouting in the aged (20 month) rat brain. AdGDNF or a control vector coding for beta-galactosidase (AdLacZ) was injected unilaterally into either the striatum or the SN. One week later, rats received a unilateral intrastriatal injection of 6-OHDA on the side of vector injection. Two weeks postlesion, rats injected with AdGDNF into either the striatum or the SN exhibited a reduction in the area of striatal denervation and increased binding of the DA transporter ligand [(125)I]IPCIT in the lesioned striatum compared to control animals. Furthermore, injections of AdGDNF into the striatum, but not the SN, increased levels of tyrosine hydroxylase mRNA in lesioned DA neurons in the SN and prevented the development of amphetamine-induced rotational asymmetry. In contrast, the level of T1 alpha-tubulin mRNA, a marker of neuronal sprouting, was not increased in lesioned DA neurons in the SN following injection of AdGDNF either into the striatum or into the SN. These results suggest that GDNF gene delivery prior to a partial lesion ameliorates damage caused by 6-OHDA in aged rats by inhibiting the degeneration of DA terminals rather than by inducing sprouting of nigrostriatal axons. Copyright 2001 Academic Press.

Corti, O. and A. Brice (2001). "Parkin and Parkinson's: more than homonymy?" Ann Neurol 50(3): 283-5.

Cowan, W. M. and E. R. Kandel (2001). "Prospects for neurology and psychiatry." Jama 285(5): 594-600.
Neurological and psychiatric illnesses are among the most common and most serious health problems in developed societies. The most promising advances in neurological and psychiatric diseases will require advances in neuroscience for their elucidation, prevention, and treatment. Technical advances have improved methods for identifying brain regions involved during various types of cognitive activity, for tracing connections between parts of the brain, for visualizing individual neurons in living brain preparations, for recording the activities of neurons, and for studying the activity of single-ion channels and the receptors for various neurotransmitters. The most significant advances in the past 20 years have come from the application to the nervous system of molecular genetics and molecular cell biology. Discovery of the monogenic disorder responsible for Huntington disease and understanding its pathogenesis can serve as a paradigm for unraveling the much more complex, polygenic disorders responsible for such psychiatric diseases as schizophrenia, manic depressive illness, and borderline personality disorder. Thus, a new degree of cooperation between neurology and psychiatry is likely to result, especially for the treatment of patients with illnesses such as autism, mental retardation, cognitive disorders associated with Alzheimer and Parkinson disease that overlap between the 2 disciplines.

Crocker, S. J., N. Wigle, et al. (2001). "NAIP protects the nigrostriatal dopamine pathway in an intrastriatal 6-OHDA rat model of Parkinson's disease." Eur J Neurosci 14(2): 391-400.
Parkinson's disease (PD) is a progressive neurodegenerative disorder of the basal ganglia, associated with the inappropriate death of dopaminergic neurons of the substantia nigra pars compacta (SNc). Here, we show that adenovirally mediated expression of neuronal apoptosis inhibitor protein (NAIP) ameliorates the loss of nigrostriatal function following intrastriatal 6-OHDA administration by attenuating the death of dopamine neurons and dopaminergic fibres in the striatum. In addition, we also addressed the role of the cysteine protease caspase-3 activity in this adult 6-OHDA model, because a role for caspases has been implicated in the loss of dopamine neurons in PD, and because NAIP is also a reputed inhibitor of caspase-3. Although caspase-3-like proteolysis was induced in the SNc dopamine neurons of juvenile rats lesioned with 6-OHDA and in adult rats following axotomy of the medial forebrain bundle, caspase-3 is not induced in the dopamine neurons of adult 6-OHDA-lesioned animals. Taken together, these results suggest that therapeutic strategies based on NAIP may have potential value for the treatment of PD.