Recent findings in tissue from multiple sclerosis victims corroborate the mechanisms documented in a growing body of research based evidence as to the steps leading to disease expression.  “Observed depletion of GSH, elevation of ceramide level and apoptosis in banked human brains from patients with neuroinflammatory diseases (e.g. x-adrenoleukodystrophy and multiple sclerosis) suggest that the intracellular level of GSH may play a crucial role in the regulation of cytokine-induced generation of ceramide leading to apoptosis of brain cells in these diseases.”

Cytokine, tumor necrosis factor‑alpha (TNF-a) or interleukin-1 beta (IL‑1b)‑mediated activation of sphingomyelinases (SMases), leads to degradation of sphingomyelin to ceramide, a sphingolipid 1,2, and the universal lipid second messenger.  This potentiated a 2-fold increase in H2O2 generation, leading to lipid peroxidation and loss of activity of respiratory chain complex IV in the GSH depleted state compared to GSH-replete mitochondria 3.  “Mitochondria are a target of ceramide produced in the signaling of TNF.3”  Pretreatment of cells so as to increase intracellular GSH inhibited the TNF-a-induced sphingomyelin hydrolysis and ceramide generation as well as cell death 4. 

 The literature implicates excessive or inappropriate generation of nitric oxide (NO) in Parkinson’s Disease, Alzheimer’s Disease, multiple sclerosis, stroke and amyotrophic lateral sclerosis 5.  “Human astrocytes released abundant NO upon stimulation with the pro-inflammatory cytokine (IL)‑1b, which was potentiated by interferon (IFN)-gamma and TNF-a.  IL-1 receptor antagonist protein markedly attenuated astrocyte NO production.6”  “It is now well documented that NO and its toxic metabolite, peroxynitrite (ONOO-–) can inhibit components of the mitochondrial respiratory chain...5”  “...neurones, in contrast to astrocytes, appear particularly vulnerable to the action of these molecules.5”   “...the susceptibility of different brain cells to NO and ONOO– exposure may be dependent on factors such as the intracellular GSH concentration...5”  “Evidence is now available to support this scenario for neurological disorders, such as multiple sclerosis.5”

Variable vulnerability to oxidative stress has been well documented in various neurological cell types.  “Astrocytes maintain high intracellular concentrations of certain antioxidants, making these cells resistant to oxidative stress relative to oligodendrocytes and neurons.7”  In fact, astrocytes appear to play a central role in the antioxidant defense of the brain.7  One of the major antioxidants used by astrocytes is GSH and, “...astroglial cells prefer cystine from [instead of] cysteine for GSH synthesis...8”

Other conditions give insight into the effect of GSH on SMases and ceramide.  “Cell culture studies of hypoxic PC12 cell death...suggest that GSH protects cells from hypoxic injury by direct inhibition of neutral SMases activity and ceramide formation...9”  This protection appears to be lost in MS patients as GSH is decreased in plaques10, and was absent in the CSF in MS.11  Protective mechanisms involving GSH appear to occur in MS, “...blood GSH was increased (p<0.01) [in MS] during exacerbation and remission as well.  This rise in this thiol is likely to be a compensatory mechanism defending the cells from further oxidant injuries.12”

The relationship between cytokines and GSH has been demonstrated in cell cultures of TNF-resistant (TNFr) and TNF-sensative (TNFs) cell lines.  “The basic level of GSH was significantly higher in the TNFr cells than in TNFs cells.  Treatment with 20 microM ceramide decreased cellular GSH in TNFs cells by 50% in contrast to an insignificant decrease in the TNFr cells.13”   

Also, the effect of intracellular GSH on neutrophil and lymphoid apoptosis give further insight into the crucial regulator role played by this important thiol.  “Because apoptosis is a critical mechanism regulating PMN survival in vivo, manipulation of PMN intracellular thiols may represent a novel therapeutic target for the regulation of cellular function.14”  “Thiol compounds, such as L-cysteine and GSH, play crucial roles in the regulation of lymphocyte proliferation.15”  “These data suggest that the inability to neutralize oxidative stress results in the apoptosis of lymphoid cells under L-cystine-and GSH-depleted conditions.  The protective effects of rADF may be explained by...enhancing the L-cystine internalization and elevating the intracellular GSH content.15” 

© 2000 AmmunoMed, LLC. 

1. Singh, I., Pahan, K., Khan, M., Singh, AK.  Cytokine-mediated induction of ceramide is redox-sensitive.  Implications to proinflammatory cytokine-mediated apoptosis in demyelinating diseases.  J Biol Chem. 273(32): 20354-62,  Aug 7, 1998.

2. Xu, J., Yeh, CH, Chen, S., He, L., Sensi, SL., Canzoniero, LM, Choi, DW., Hsu, CY.  Involvement of de novo ceramide biosynthesis in tumor necrosis factor-alpha/cycloheximide-induced cerebral endothelial cell death.  J Biol Chem. 273(26): 16521-6,  June 26, 1998.

3. Garcia-Ruiz, C., Colell, A., Mari, M., Morales, A., Fernandez-Checa, JC.  Direct effect of ceramide on the mitochondrial electron transport chain leads to generation of reactive oxygen species.  Role of mitochondrial glutathione.  J Biol Chem.  272(17): 11369-77, Apr 25, 1997.

4. Liu, B., Andrieu,Abadie, N., Levade, T., Zhang, P., Obeid, LM., Hannun, YA.  Glutathione regulation of neutral sphingomyelinase in tumor necrosis factor-alpha-induced cell death.  J Biol Chem.  273(18): 11313-20, May 1, 1998.

5.  Heales, SJ., Bolanos, JP., Stewart, VC., Brookes, PS., Land, JM.., Clark, JB.  Nitric oxide, mitochondria and neurological disease.  Biochim Biophys Acta.  1410(2): 215-28, Feb 9, 1999.

6. Hu, S., Sheng, WS., Peterson, PK., Chao, CC.  Differential regulation by cytokines of human astrocyte nitric oxide production.  Glia. 15(4): 491-4, Dec 1995.

7. Wilson, John X.  Antioxidant defense of the brain: a role for astrocytes1.  Can. J. Physiol. Pharmacol. 75: 1149-1163, 1997.

8. Kranich, O., Dringen, R., Sandberg, M., Hamprecht, B.  Utilization of cysteine andcysteine precursors for the synthesis of glutathione in astroglial cultures: preference for cystine.  Glia. 22(1): 11-8, Jan. 1998.

9. Yoshimura, S., Banno, Y., Nakashima, S., Hayashi, K., Yamakawa, H., Sawada, M., Sakai, N., Nozawa, Y.  Inhibition of neutral sphingomyelinase activation and ceramide formation by glutathione in hypoxic PC12 cell death.   J Neurochem. 73(2): 675-83, Aug. 1999

10. Langemann, H., Kabiersch, A., Newcombe, J.  Measurement of low-molecular-weight antioxidants, uric acid, tyrosine and tryptophan in plaques and white matter from patients with multiple sclerosis.  Eur Neurol. 32(5): 248-52, 1992.

11. Ronquist, G., Frithz, G.  Adenylate kinase activity and glutathione concentration of cerebrospinal fluid in different neurological disorders.  Eur Neurol. 18(2): 106-10, 1979.

12. Karg, E., Klivenyi, P., Nemeth, I., Bencski, K., Pinter, S., Vecsei, L.  Nonenzymatic antioxidants of blood in multiple sclerosis.  J Neurol. 246(7): 533-9, July 1999.

13. Davis, MA., Flaws, JA., Young, M., Collins, K., Colburn, NH.  Effect of ceramide on intracellular glutathione determines apoptotic or necrotic cell death of JB6 tumor cells.  Toxicol Sci. 53(1): 48-55, Jan. 2000.

14. Watson, RW., Rotstein, OD., Nathens, AB., Dackiw, AP., Marshall, JC.  Thiol-mediated redox regulation of neutrophil apoptosis.  Surgery.  120(2): 150-7; discussion 157-8, Aug. 1996. 

15. Iwata, S., Hori, T., Sato, N., Hirota, K., Sasada, T., Mitsui, A., Hirakawa, T., Yodoi, J.  Adult T cell leukemia (ATL)-derived factor/human thioredoxin prevents apoptosis of lymphoid cells induced by L-cystine and glutathione depletion: possible involvement of thiol-mediated redox regulation in apoptosis caused by pro-oxidant state.  J Immunol. 158(7): 3108-17, April 1, 1997.


J Neurosci Res. 2002 Nov 15;70(4):580-7.

Nitric oxide synthase is present in the cerebrospinal fluid of patients with active multiple sclerosis and is associated with increases in cerebrospinal fluid protein nitrotyrosine and S-nitrosothiols and with changes in glutathione levels.

Calabrese V, Scapagnini G, Ravagna A, Bella R, Foresti R, Bates TE, Giuffrida Stella AM, Pennisi G.

Biochemistry and Molecular Biology Section, Department of Chemistry, Faculty of Medicine, University of Catania, Catania, Italy.

Nitric oxide (NO) is hypothesized to play a role in the immunopathogenesis of multiple sclerosis (MS). Increased levels of NO metabolites have been found in patients with MS. Peroxynitrite, generated by the reaction of NO with superoxide at sites of inflammation, is a strong oxidant capable of damaging tissues and cells. Inducible NO synthase (iNOS) is up-regulated in the CNS of animals with experimental allergic encephalomyelitis (EAE) and in patients with MS. In this study, Western blots of cerebrospinal fluid (CSF) from patients with MS demonstrated the presence of iNOS, which was absent in CSF from control subjects. There was also NOS activity present in both MS and control CSF. Total NOS activity was increased (by 24%) in the CSF from MS patients compared with matched controls. The addition of 0.1 mM ITU (a specific iNOS inhibitor) to the samples did not change the activity of the control samples but decreased the NOS activity in the MS samples to almost control levels. The addition of 1 mM L-NMMA (a nonisoform specific NOS inhibitor), completely inhibited NOS activity in CSF from control and MS subjects. Nitrotyrosine immunostaining of CSF proteins was detectable in controls but was greatly increased in MS samples. There were also significant increases in CSF nitrate + nitrite and oxidant-enhanced luminescence in MS samples compared with controls. Additionally, a significant decrease in reduced glutathione and significant increases in oxidized glutathione and S-nitrosothiols were found in MS samples compared with controls. Parallel changes in NO metabolites were observed in the plasma of MS patients, compared with controls, and accompanied a significant increase of reduced glutathione. These data strongly support a role for nitrosative stress in the pathogenesis of MS and indicate that therapeutic strategies focussed on decreasing production of NO by iNOS and/or scavenging peroxynitrite may be useful in alleviating the neurological impairments that occur during MS relapse. Copyright 2002 Wiley-Liss, Inc.

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PMID: 12404512 [PubMed - indexed for MEDLINE]


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