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MS and Nitric Oxide
(22 References)
(2003). "[In Process Citation]." Lik Sprava(3-4): 52-6.
The article presents data on the chief mechanisms of human cell apoptosis, on the role of nitric oxide (NO) in modulation of the above mechanisms in cells of normal tissues and organs and in multiple sclerosis (MS) as well. Aspects are analyzed of NO action in the processes of apoptosis in MS. Corticosteroid pulse therapy is recognized as a powerful inducer of T-lymphocyte apoptosis in the condition under consideration.
Acar, G., F. Idiman, et al. (2003). "Nitric oxide as an activity marker in multiple sclerosis." J Neurol 250(5): 588-92.
Nitric oxide (NO) molecules have one of the most important roles in the pathogenesis of multiple sclerosis (MS). It has been stated that a continuous and high concentration of NO metabolites in CSF and in the serum of MS patients in relapse may cause toxic damage to myelin and oligodendroglia. The aim of this study was to investigate whether NO is a marker of disease activity and is correlated with other disease activity markers such as active lesions on brain magnetic resonance imaging (MRI) and increased immunoglobulin G (IgG) index.Cerebrospinal fluid (CSF) and peripheral serum (PS) samples were taken from patients with definite MS (n = 24) during relapse and remission and from control subjects (n = 18). The Griess reaction was used to measure the NO metabolites, nitrite and nitrate in CSF and PS. Cranial MRI was carried out with triple dose (0,3 mmol/kg) gadolinium and the IgG index was determined.Nitrite and nitrate concentrations (NNCs) of CSF were 11.16 +/- 8.60 micromol/ml in relapse and 6.72 +/- 3.50 micromol/ml in remission, whereas in PS they were 12.89 +/- 7.62 micromol/ml during relapse and 12.35 +/- 6.62 micromol/ml during remission. In control subjects NNCs in CSF and PS were 7.42 +/- 2.81 micromol/ml and 4.37 +/- 1.63 micromol/ml respectively. NNCs in CSF during relapse period were significantly higher than those of both remission phase and control subjects (p = 0.000). Although serum NNCs did not differ in relapse and remission, they were still higher than normal controls. Validity analysis revealed that NNC measurement in CSF was 71 % specific and 66 % sensitive to disease activity. The most important result was the significant correlation of increased NNCs with the existence of active lesion in cranial MRI and an increase in IgG index (p < 0.05).In conclusion, these results add background data to assist in further outlining the possible role of NO in the pathogenesis of MS. Together with the other markers it may be used as an activity marker in relapses of MS.
Blanco, Y., J. Yague, et al. (2003). "No association of inducible nitric oxide synthase gene ( NOS2A) to multiple sclerosis." J Neurol 250(5): 598-600.
Nitric oxide (NO) is a nonspecific inflammatory mediator that has been involved in the pathogenesis of multiple sclerosis (MS). The influence of the promoter polymorphism of inducible NO synthase gene ( NOS2A) on susceptibility and outcome was studied in 140 MS Spanish patients and 147 healthy controls matched for sex, age, and ethnicity. No association was found between MS susceptibility, course or outcome of the disease, and NOS2A polymorphisms.
Boven, L. A., N. Vergnolle, et al. (2003). "Up-regulation of proteinase-activated receptor 1 expression in astrocytes during HIV encephalitis." J Immunol 170(5): 2638-46.
Proteinase-activated receptor 1 (PAR-1) is a G protein-coupled receptor that is activated by thrombin and is implicated in the pathogenesis of inflammation. Although PAR-1 is expressed on immunocompetent cells within the brain such as astrocytes, little is known about its role in the pathogenesis of inflammatory brain diseases. Herein, we investigated PAR-1 regulation of brain inflammation by stimulating human astrocytic cells with thrombin or the selective PAR-1-activating peptide. Activated cells expressed significantly increased levels of IL-1 beta, inducible NO synthase, and PAR-1 mRNA. Moreover, supernatants of these same cells were neurotoxic, which was inhibited by an N-methyl-D-aspartate receptor antagonist. Striatal implantation of the PAR-1-activating peptide significantly induced brain inflammation and neurobehavioral deficits in mice compared with mice implanted with the control peptide or saline. Since HIV-related neurological disease is predicated on brain inflammation and neuronal injury, the expression of PAR-1 in HIV encephalitis (HIVE) was investigated. Immunohistochemical analysis revealed that PAR-1 and (pro)-thrombin protein expression was low in control brains, but intense immunoreactivity was observed on astrocytes in HIVE brains. Similarly, PAR-1 and thrombin mRNA levels were significantly increased in HIVE brains compared with control and multiple sclerosis brains. These data indicated that activation and up-regulation of PAR-1 probably contribute to brain inflammation and neuronal damage during HIV-1 infection, thus providing new therapeutic targets for the treatment of HIV-related neurodegeneration.
Calabrese, V., G. Scapagnini, et al. (2003). "Disruption of thiol homeostasis and nitrosative stress in the cerebrospinal fluid of patients with active multiple sclerosis: evidence for a protective role of acetylcarnitine." Neurochem Res 28(9): 1321-8.
Recent studies suggest that NO and its reactive derivative peroxynitrite are implicated in the pathogenesis of multiple sclerosis (MS). Patients dying with MS demonstrate increased astrocytic inducible nitric oxide synthase activity, as well as increased levels of iNOS mRNA. Peroxynitrite is a strong oxidant capable of damaging target tissues, particularly the brain, which is known to be endowed with poor antioxidant buffering capacity. Inducible nitric oxide synthase is upregulated in the central nervous system (CNS) of animals with experimental allergic encephalomyelitis (EAE) and in patients with MS. We have recently demonstrated in patients with active MS a significant increase of NOS activity associated with increased nitration of proteins in the cerebrospinal fluid (CSF). Acetylcarnitine is proposed as a therapeutic agent for several neurodegenerative disorders. Accordingly, in the present study, MS patients were treated for 6 months with acetylcarnitine and compared with untreated MS subjects or with patients noninflammatory neurological conditions, taken as controls. Western blot analysis showed in MS patients increased nitrosative stress associated with a significant decrease of reduced glutathione (GSH). Increased levels of oxidized glutathione (GSSG) and nitrosothiols were also observed. Interestingly, treatment of MS patients with acetylcarnitine resulted in decreased CSF levels of NO reactive metabolites and protein nitration, as well as increased content of GSH and GSH/GSSG ratio. Our data sustain the hypothesis that nitrosative stress is a major consequence of NO produced in MS-affected CNS and implicate a possible important role for acetylcarnitine in protecting brain against nitrosative stress, which may underlie the pathogenesis of MS.
Danilov, A. I., M. Andersson, et al. (2003). "Nitric oxide metabolite determinations reveal continuous inflammation in multiple sclerosis." J Neuroimmunol 136(1-2): 112-8.
Nitric oxide (NO) is formed as a consequence of induction of the iNOS enzyme during inflammatory disorders. To investigate NO production in multiple sclerosis (MS), we determined the concentrations of its oxidation products (NOx) in the cerebrospinal fluid (CSF) and plasma of 61 MS patients. The patients were divided into three groups on the basis of their clinical disease activity. The total levels of NOx in CSF were significantly increased in all MS groups as compared to healthy controls and tension headache patients. CSF nitrite correlated with clinical disease activity. At exacerbation, the CSF nitrite levels exceed the plasma level. This suggests that clinical disease activity is due to a CNS inflammatory response, which is more intense and qualitatively different from that during clinical stable phases. This study supports NO involvement in the pathogenesis of MS and determination of nitrite levels may be useful a surrogate marker for disease activity.
Dasgupta, S., Y. Zhou, et al. (2003). "Sodium phenylacetate inhibits adoptive transfer of experimental allergic encephalomyelitis in SJL/J mice at multiple steps." J Immunol 170(7): 3874-82.
Experimental allergic encephalomyelitis (EAE) is the animal model for multiple sclerosis. The present study underlines the importance of sodium phenylacetate (NaPA), a drug approved for urea cycle disorders, in inhibiting the disease process of adoptively transferred EAE in female SJL/J mice at multiple steps. Myelin basic protein (MBP)-primed T cells alone induced the expression of NO synthase (iNOS) and the activation of NF-kappaB in mouse microglial cells through cell-cell contact. However, pretreatment of MBP-primed T cells with NaPA markedly inhibited its ability to induce microglial expression of iNOS and activation of NF-kappaB. Consistently, adoptive transfer of MBP-primed T cells, but not that of NaPA-pretreated MBP-primed T cells, induced the clinical symptoms of EAE in female SJL/J mice. Furthermore, MBP-primed T cells isolated from NaPA-treated donor mice were also less efficient than MBP-primed T cells isolated from normal donor mice in inducing iNOS in microglial cells and transferring EAE to recipient mice. Interestingly, clinical symptoms of EAE were much less in mice receiving NaPA through drinking water than those without NaPA. Similar to NaPA, sodium phenylbutyrate, a chemically synthesized precursor of NaPA, also inhibited the disease process of EAE. Histological and immunocytochemical analysis showed that NaPA inhibited EAE-induced spinal cord mononuclear cell invasion and normalized iNOS, nitrotyrosine, and p65 (the RelA subunit of NF-kappaB) expression within the spinal cord. Taken together, our results raise the possibility that NaPA or sodium phenylbutyrate taken through drinking water or milk may reduce the observed neuroinflammation and disease process in multiple sclerosis patients.
Delgado, M. and D. Ganea (2003). "Vasoactive intestinal peptide prevents activated microglia-induced neurodegeneration under inflammatory conditions: potential therapeutic role in brain trauma." Faseb J 17(13): 1922-4.
In most neurodegenerative disorders, including multiple sclerosis, Parkinson's disease, and Alzheimer's disease, a massive neuronal cell death occurs as a consequence of an uncontrolled inflammatory response, where activated microglia and its cytotoxic agents play a crucial pathologic role. Because current treatments for these diseases are not effective, several regulatory molecules termed "microglia-deactivating factors" recently have been the focus of considerable research. Vasoactive intestinal peptide (VIP) is a neuropeptide with a potent anti-inflammatory effect, which has been found to protect from other inflammatory disorders, such as endotoxic shock and rheumatoid arthritis. In the present study, we investigate the effect of VIP on inflammation-mediated neurodegeneration in vitro and in vivo as well as on the putative neuroprotective effect of VIP on experimental pathological conditions in which central nervous system (CNS) inflammation is involved, such as brain trauma. The involvement of activated microglia and their derived cytotoxic products is also studied. VIP has a clear neuroprotective effect on inflammatory conditions by inhibiting the production of microglia-derived proinflammatory factors (tumor necrosis factor alpha, interleukin-1beta, nitric oxide). In this sense, VIP prevents neuronal cell death following brain trauma by reducing the inflammatory response of neighboring microglia. Therefore, VIP emerges as a valuable neuroprotective agent for the treatment of pathologic conditions of the CNS where inflammation-induced neurodegeneration occurs.
Dogusan, Z., N. Martens, et al. (2003). "Effects of prolactin on cloned human T-lymphocytes." Endocrine 20(1-2): 171-6.
To evaluate the possible role of prolactin (PRL) in T-lymphocytes, we monitored gene induction in one cytotoxic T-lymphocyte (CTL) clone derived from a patient with hemochromatosis and in several T-helper clones generated from a normal donor and a patient with multiple sclerosis. The CTL clone expressed conventional PRL receptor (PRLR), and PRL induced the expression of suppressor of cytokine signaling-3 (SOCS-3) and increased the expression of SOCS-2 and cytokine-inducible src homology-2 containing protein (CIS, another member of the SOCS family). As is the case in granulocytes, expression of a conventional receptor for PRL could not be shown by polymerase chain reaction analysis on three helper clones. In addition, as in granulocytes, PRL modulated the expression of genes such as the interferon-regulatory factor-1, inducible nitric oxide synthase, CIS, and SOCS-2. These effects were also elicited with ovine PRL and could be prevented by anti-PRL antibodies. Thus, the use of clones allowed the detection of direct effects of PRL on T-cells, even when these have few or no detectable PRLR, confirming that human T-lymphocytes are targets for PRL.
Garcion, E., L. Sindji, et al. (2003). "Treatment of experimental autoimmune encephalomyelitis in rat by 1,25-dihydroxyvitamin D3 leads to early effects within the central nervous system." Acta Neuropathol (Berl) 105(5): 438-48.
We report here that curative treatment of the multiple sclerosis paradigm, chronic relapsing experimental autoimmune encephalomyelitis (EAE) of the Lewis rat, by 1,25-dihydroxyvitamin D(3 )(1,25-D3) leads to a rapid clinical improvement accompanied by an inhibition of CD4, MHC class II and type II nitric oxide synthase (NOS II) expression in the posterior areas of the central nervous system (CNS). In contrast, the hormone has no effect on transforming growth factor-beta1 transcripts. Computer analysis of the NOS II promoter, expressed by microglia and astrocytes, reveals consensus sequence for vitamin D receptor binding, emphasizing the idea that 1,25-D3 may regulate some aspects of EAE by acting directly on CNS constituent cells. We also demonstrate that vitamin D deprivation leads to minimal effects on the kinetic profile of EAE accompanied by a moderate exacerbation of the clinical symptoms. Interestingly, curative treatment of vitamin D-deprived rats with a non-toxic-1,25-D3 analogue (MC1288) strongly inhibited EAE symptoms, thus promulgating the potential interest of such compounds in the management of multiple sclerosis.
Hisahara, S., H. Okano, et al. (2003). "Caspase-mediated oligodendrocyte cell death in the pathogenesis of autoimmune demyelination." Neurosci Res 46(4): 387-97.
Multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), are inflammatory diseases of the central nervous system (CNS) characterized by localized areas of demyelination. MS is believed to be an autoimmune disorder mediated by activated immune cells such as T- and B-lymphocytes and macrophages/microglia. Lymphocytes are primed in the peripheral tissues by antigens, and clonally expanded cells infiltrate the CNS. They produce large amounts of inflammatory and cytokines that lead to demyelination and axonal degeneration. Although several studies have shown that oligodendrocytes (OLGs), the myelin-forming glial cells in the CNS, are sensitive to cell death stimuli, such as cytotoxic cytokines, anti-myelin antibodies, nitric oxide, and oxidative stress, in vitro, the mechanisms underlying injury to the OLGs in MS/EAE remain unclear. Transgenic mice that express the anti-apoptotic protein specifically in OLGs and caspase-11-deficient mice are significantly resistant to EAE induction. Histopathological analyses show that the number of caspase-activated OLGs and dead OLGs are reduced in the CNS of these mice. The numbers of infiltrating immune cells and the amounts of cytokines are also markedly reduced in EAE lesions. Therefore, caspase-mediated OLG death leads to the exacerbation of demyelination and the deterioration of neurological manifestations by inducing local inflammatory events.
Jolivalt, C. G., R. B. Howard, et al. (2003). "A novel nitric oxide scavenger in combination with cyclosporine A ameliorates experimental autoimmune encephalomyelitis progression in mice." J Neuroimmunol 138(1-2): 56-64.
Immunotherapy improves experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis (MS), while excessive production of nitric oxide (NO) has been implicated in the pathogenesis of this disease. Here, we show that disease progression in SJL/J mice with EAE is improved after treatment with either a subtherapeutic dose of cyclosporine A (CsA) or NOX-100, a nitric oxide scavenger. Importantly, the impact of subtherapeutic doses of CsA in combination with NOX-100 on disease progression in EAE was greater than that attained with either agent alone and led to near total protection. CNS inflammation and gene expression of proinflammatory cytokines and iNOS were also significantly reduced after treatment. These observations point to the potential therapeutic utility of NOX-100 as a dose-reducing agent for CsA in the treatment of MS.
Kahl, K. G., J. Zielasek, et al. (2003). "Protective role of the cytokine-inducible isoform of nitric oxide synthase induction and nitrosative stress in experimental autoimmune encephalomyelitis of the DA rat." J Neurosci Res 73(2): 198-205.
The pathogenic role of nitric oxide (NO) in multiple sclerosis (MS) remains controversial. Some groups have reported a pathogenic role of NO in experimental autoimmune encephalomyelitis (EAE), an animal model of some aspects of MS, whereas we and others have found a disease-suppressive effect of NO in EAE. Because the previously used EAE models have a mainly monophasic inflammatory disease course, distinct from MS, we here studied EAE in the DA rat, which better models the demyelinating and relapsing disease course of human MS. The induction of EAE in DA rats led to 1) severe inflammatory infiltrates mainly in the lumbar spinal cord; 2) an up-regulation of the activity of the cytokine-inducible isoform of NO synthases (NOS-II); and 3) increased tissue protein tyrosine nitration, as indicated by peroxynitrite (ONOO(-)), as a marker of nitrosative stress. Sources of superoxide metabolism, i.e., NADPH oxidase, myeloperoxidase, and superoxide dismutase, remained unchanged. Early treatment of animals with aminoguanidine, a relatively selective inhibitor of NOS-II, lowered nitrotyrosine immunoreactivity but at the same time led to more severe disease and pronounced inflammatory infiltrates in the lumbar spinal cord. Our results suggest a rather protective role of NOS-II induction and nitrosative stress in EAE in DA rats and support the hypothesis of a disease-mitigating immunomodulatory role of NO in this animal model of MS.
Kapoor, R., M. Davies, et al. (2003). "Blockers of sodium and calcium entry protect axons from nitric oxide-mediated degeneration." Ann Neurol 53(2): 174-80.
Axonal degeneration can be an important cause of permanent disability in neurological disorders in which inflammation is prominent, including multiple sclerosis and Guillain-Barre syndrome. The mechanisms responsible for the degeneration remain unclear, but it is likely that axons succumb to factors produced at the site of inflammation, such as nitric oxide (NO). We previously have shown that axons exposed to NO in vivo can undergo degeneration, especially if the axons are electrically active during NO exposure. The axons may degenerate because NO can inhibit mitochondrial respiration, leading to intraaxonal accumulation of Na(+) and Ca(2+) ions. Here, we show that axons can be protected from NO-mediated damage using low concentrations of Na(+) channel blockers, or an inhibitor of Na(+)/Ca(2+) exchange. Our findings suggest a new strategy for axonal protection in an inflammatory environment, which may be effective in preventing the accumulation of permanent disability in patients with neuroinflammatory disorders.
Kayhan, B., R. Aharoni, et al. (2003). "Glatiramer acetate (Copaxone) regulates nitric oxide and related cytokine secretion in experimental autoimmune encephalomyelitis." Immunol Lett 88(3): 185-92.
Nitric oxide (NO) is an important mediator involved in the pathogenesis of experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS). We examined the effect of glatiramer acetate (GA), an agent with suppressing effect on EAE and of therapeutic value for the treatment of MS, on the secretion of NO, as well as of the NO regulating cytokines. We observed that induction of EAE leads to 4-fold elevation in NO secretion and that treatment of the EAE mice by GA indeed leads to a significant reduction in the NO secretion by the splenocytes in response to the encephalitogen. A parallel decrease was observed in the secretion of the NO inducing cytokine IL-1beta. On the other hand, the secretion level of NO modulating cytokines IL-10 and IL-13 was significantly augmented. The correlation between these findings and the therapeutic effect of GA is discussed.
Lee, J., H. Ryu, et al. (2003). "Translational control of inducible nitric oxide synthase expression by arginine can explain the arginine paradox." Proc Natl Acad Sci U S A 100(8): 4843-8.
L-Arginine is the only endogenous nitrogen-containing substrate of NO synthase (NOS), and it thus governs the production of NO during nervous system development as well as in disease states such as stroke, multiple sclerosis, Parkinson's disease, and HIV dementia. The "arginine paradox" refers to the dependence of cellular NO production on exogenous L-arginine concentration despite the theoretical saturation of NOS enzymes with intracellular L-arginine. Herein, we report that decreased availability of L-arginine blocked induction of NO production in cytokine-stimulated astrocytes, owing to inhibition of inducible NOS (iNOS) protein expression. However, activity of the promoter of the iNOS gene, induction of iNOS mRNA, and stability of iNOS protein were not inhibited under these conditions. Our results indicate that inhibition of iNOS activity by arginine depletion in stimulated astrocyte cultures occurs via inhibition of translation of iNOS mRNA. After stimulation by cytokines, uptake of L-arginine negatively regulates the phosphorylation status of the eukaryotic initiation factor (eIF2 alpha), which, in turn, regulates translation of iNOS mRNA. eIF2 alpha phosphorylation correlates with phosphorylation of the mammalian homolog of yeast GCN2 eIF2 alpha kinase. As the kinase activity of GCN2 is activated by phosphorylation, these findings suggest that GCN2 activity represents a proximal step in the iNOS translational regulation by availability of l-arginine. These results provide an explanation for the arginine paradox for iNOS and define a distinct mechanism by which a substrate can regulate the activity of its associated enzyme.
Lieb, K., S. Engels, et al. (2003). "Inhibition of LPS-induced iNOS and NO synthesis in primary rat microglial cells." Neurochem Int 42(2): 131-7.
Nitric oxide (NO) has been implicated in the etiopathology of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), and inhibition of NO synthesis has been proposed to be a possible mechanism of action of drugs to treat MS. In the present study, we investigated the inhibitory effect on NO synthesis of various steroids, cytokines and drugs used or proposed for the treatment of MS. As a model system, we used primary rat microglial cells which produce NO synthase and subsequently release NO upon stimulation with lipopolysaccharide (LPS). Among the substances tested, the glucocorticoids prednisone, hydrocortisone, dexamethasone and progesterone as well as transforming growth factor-beta (TGF-beta) dose-dependently inhibited LPS-induced nitric oxide synthase (iNOS) and NO synthesis. In contrast, COP-1, the phosphodiesterase inhibitors rolipram and pentoxifylline, the cytokines interleukin-10 (IL-10) and interferon-beta (IFN-beta) as well as the steroids beta-estradiol, testosterone, and dehydroepiandrosterone (DHEA) showed no inhibitory effect. Cholesterol slightly, but not significantly, increased LPS-induced nitric oxide synthesis. We conclude from the present study that with respect to treatment of MS, inhibition of NO synthesis may be an important mechanism of action of glucocorticoids and transforming growth factor-beta, but not of other drugs used or proposed to treat MS.
Mizuno, T., J. Kawanokuchi, et al. (2003). "Production and neuroprotective functions of fractalkine in the central nervous system." Brain Res 979(1-2): 65-70.
The CX3C-chemokine, fractalkine is reportedly to be expressed in the central nervous system, and up-regulated in certain pathological conditions, such as HIV encephalopathy and multiple sclerosis. In the present study, we examined the production of fractalkine and the expression of its receptor, CX3CR1 in murine glial and neuronal cell in vitro, and investigated its neuroprotective functions. Both fractalkine and CX3CR1 were expressed constitutively in neurons, microglia, and astrocytes. Neither the production of fractalkine nor its receptor expression was up-regulated by lipopolysaccharide (LPS), as measured by mRNA expression and protein synthesis. Fractalkine dose-dependently suppressed the production of nitric oxide (NO), interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha with activated microglia. It also significantly suppressed neuronal cell death induced by microglia activated with LPS and interferon-gamma, in a dose-dependent manner. These results suggest the possible functions of fractalkine as an intrinsic inhibitor against neurotoxicity by activated microglia.
Palace, J. (2003). "Clinical and laboratory characteristics of secondary progressive MS." J Neurol Sci 206(2): 131-4.
Secondary progressive (SP) MS follows on from but is distinct in its clinical picture from relapsing remitting (RR) MS. Diagnosis is usually straightforward except during the transitional stage when the two phenotypes merge. It is clear that most patients that start with relapsing remitting MS will develop SP disease, although the underlying pathogenesis that causes this change is subject to much debate. Clinical features such as pattern and site of symptoms, and age of onset, in the relapsing remitting stage versus progressive disease, suggests a difference in the pathophysiology. Laboratory markers may give insight into the disease mechanisms. Measures of urinary and CSF myelin basic protein-like material (MBPLM) indicate demyelination and subsequent oligodendrocyte and axonal loss. Tertiary neutralising antibodies to MBP antibodies could attenuate remission and lead to continuous progression, and neuronal antibodies found in SP disease may contribute to the axonal loss. In addition, differences in nitric oxide and other inflammatory cytokine patterns might either be secondary to or causative of the pathological mechanisms.Greater understanding of progressive MS is a priority considering permanent disability results almost entirely from this stage of the disease.
Platten, M., K. Eitel, et al. (2003). "Involvement of protein kinase Cdelta and extracellular signal-regulated kinase-2 in the suppression of microglial inducible nitric oxide synthase expression by N-[3,4-dimethoxycinnamoyl]-anthranilic acid (tranilast)." Biochem Pharmacol 66(7): 1263-70.
Excess nitric oxide (NO) in the brain released by microglial cells contributes to neuronal damage in various pathologies of the central nervous system (CNS) including neurodegenerative diseases and multiple sclerosis. N-[3,4-Dimethoxycinnamoyl]-anthranilic acid (tranilast, TNL) is an anti-allergic compound which suppresses the activation of monocytes. We show that inducible nitric oxide synthase (iNOS) mRNA and protein expression and the release of NO from N9 microglial cells stimulated with the bacterial endotoxin lipopolysaccharide (LPS) are inhibited when the cells are exposed to TNL. TNL fails to modulate LPS-stimulated nuclear factor-kappaB (NF-kappaB) reporter gene activity and phosphorylation of inhibitory kappaB (IkappaB), indicating that NF-kappaB is not involved in the TNL-mediated suppression of LPS-induced iNOS expression. Moreover, TNL inhibits LPS-induced phosphorylation of extracellular signal-regulated kinase 2 (ERK-2). Finally, TNL abolishes translocation of protein kinase Cdelta (PKCdelta) to the nucleus and suppresses the phosphorylation of the PKCdelta substrate, myristoylated alanin-rich C kinase substrate (MARCKS). We conclude that the anti-allergic compound TNL suppresses microglial iNOS induction by LPS via inhibition of a signalling pathway involving PKCdelta and ERK-2.
Siebert, H. and W. Bruck (2003). "The role of cytokines and adhesion molecules in axon degeneration after peripheral nerve axotomy: a study in different knockout mice." Brain Res 960(1-2): 152-6.
The loss of axons and axonal dysfunction has become of outstanding interest with respect to degenerative and inflammatory diseases of the central and peripheral nervous system. In particular in terms of demyelinating diseases such as multiple sclerosis it is important to know the mechanisms which are responsible for the degeneration and destruction of axons. Here we focused on the loss or preservation of axons after induction of Wallerian degeneration in transected mouse sciatic nerves. We examined the distal transected nerve segments of different knockout mice (ICAM-1; TNF-alpha; iNOS; IL-6) 6 days after axotomy. Despite a distinct number of invading macrophages which phagocytosed most of the myelin and axonal debris, we were able to demonstrate, that animals which are deficient for the cell adhesion molecule ICAM-1 and the cytokine TNF-alpha showed a significantly higher number of preserved axons within the degenerating distal nerve stump. Since macrophage invasion is known to be impaired in the absence of ICAM-1, these data indicate an essential role of these cells and their secreted factors, namely TNF-alpha, but not nitric oxide or IL-6 in the destruction of the axonal cytoskeleton in the peripheral nervous system.
Stuve, O., S. Youssef, et al. (2003). "Statins as potential therapeutic agents in neuroinflammatory disorders." Curr Opin Neurol 16(3): 393-401.
PURPOSE OF REVIEW: Multiple sclerosis is a central nervous system inflammatory demyelinating disease that is thought to have an autoimmune pathogenesis. Recent results indicate that 'statins', 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, which are the most commonly used oral cholesterol-lowering drugs, have immunomodulatory properties. In this article we will review those findings that indicate that statins may be beneficial in the treatment of multiple sclerosis, neurodegenerative disease, and ischemic stroke. RECENT FINDINGS: It was reported that statin treatment could either inhibit or reverse chronic and relapsing experimental autoimmune encephalomyelitis, a model of multiple sclerosis. Several immunomodulatory properties of statins may account for their beneficial clinical effect: Statins decreased the migration of leukocytes into the central nervous system, inhibited MHC class II and costimulatory signals required for activation of proinflammatory T cells, induced a T(H)2 phenotype in T cells, and decreased the expression of inflammatory mediators in the central nervous system, including nitric oxide and tumor necrosis factor alpha. It was also demonstrated that statin use significantly reduced beta-amyloid secretion in the cerebrospinal fluid of experimental animals. Clinically, there is emerging evidence that statins have beneficial effects in patients with multiple sclerosis, Alzheimer's disease, and ischemic stroke. SUMMARY: In-vitro studies have indicated that statins may have anti-inflammatory properties. Results from in-vivo animal models suggest that statins may be beneficial in treatment of different central nervous system conditions. Larger scale, randomized, double-blind trials are needed to validate the role of statins as a treatment of inflammatory central nervous system diseases.