Role of the Bruton tyrosine kinase pathway in multiple sclerosis.

Multiple sclerosis (MS) is a chronic, immune-mediated, neurodegenerative condition that results in progressive accumulation of disability over the course of the disease. MS presents heterogeneously, and, as the disease progresses, patients develop a range of physical and neurologic problems that include reduced mobility, cognitive impairment, weakness, fatigue, pain, and defects in speech or vision. Economically, MS is costly, including both direct costs stemming from clinical care and medications and the indirect costs of productivity losses. These costs pose a substantial burden to patients, families, caregivers, employers, and society. There are 21 approved disease-modifying therapies for MS across several drug classes. The importance of early MS treatment has been confirmed, and progress has been made in the treatment of relapsing-remitting MS, although this progress has not been replicated for progressive presentations of the disease. Ongoing research continues to elucidate the exact mechanisms of disease in MS as well as potential new treatment strategies that may better address current gaps, such as disability progression in secondary progressive MS without activity. One of the novel pathways under investigation is the inhibition of Bruton tyrosine kinase, a cytoplasmic tyrosine kinase, which is expressed in B cells and other potentially targetable hematopoietic lineage cells. This review examines emerging hypotheses that targeting both B cells and myeloid cells within the periphery and central nervous system could yield clinical effects in key areas of MS pathophysiology that are currently unaddressed.

Teriflunomide Treatment of Multiple Sclerosis Selectively Modulates CD8 Memory T Cells.

Background and Objectives: Inhibition of de novo pyrimidine synthesis in proliferating T and B lymphocytes by teriflunomide, a pharmacological inhibitor of dihydroorotate dehydrogenase (DHODH), has been shown to be an effective therapy to treat patients with MS in placebo-controlled phase 3 trials. Nevertheless, the underlying mechanism contributing to the efficacy of DHODH inhibition has been only partially elucidated. Here, we aimed to determine the impact of teriflunomide on the immune compartment in a longitudinal high-dimensional follow-up of patients with relapse-remitting MS (RRMS) treated with teriflunomide. Methods: High-dimensional spectral flow cytometry was used to analyze the phenotype and the function of innate and adaptive immune system of patients with RRMS before and 12 months after teriflunomide treatment. In addition, we assessed the impact of teriflunomide on the migration of memory CD8 T cells in patients with RRMS, and we defined patient immune metabolic profiles. Results: We found that 12 months of treatment with teriflunomide in patients with RRMS does not affect the B cell or CD4 T cell compartments, including regulatory TREG follicular helper TFH cell and helper TH cell subsets. In contrast, we observed a specific impact of teriflunomide on the CD8 T cell compartment, which was characterized by decreased homeostatic proliferation and reduced production of TNFα and IFNγ. Furthermore, we showed that DHODH inhibition also had a negative impact on the migratory velocity of memory CD8 T cells in patients with RRMS. Finally, we showed that the susceptibility of memory CD8 T cells to DHODH inhibition was not related to impaired metabolism. Discussion: Overall, these findings demonstrate that the clinical efficacy of teriflunomide results partially in the specific susceptibility of memory CD8 T cells to DHODH inhibition in patients with RRMS and strengthens active roles for these T cells in the pathophysiological process of MS.

PRMT5 Promotes Cyclin E1 and Cell Cycle Progression in CD4 Th1 Cells and Correlates With EAE Severity.

Multiple Sclerosis (MS) is a debilitating central nervous system disorder associated with inflammatory T cells. Activation and expansion of inflammatory T cells is thought to be behind MS relapses and influence disease severity. Protein arginine N-methyltransferase 5 (PRMT5) is a T cell activation-induced enzyme that symmetrically dimethylates proteins and promotes T cell proliferation. However, the mechanism behind PRMT5-mediated control of T cell proliferation and whether PRMT5 contributes to diseases severity is unclear. Here, we evaluated the role of PRMT5 on cyclin/cdk pairs and cell cycle progression, as well as PRMT5's link to disease severity in an animal model of relapsing-remitting MS. Treatment of T helper 1 (mTh1) cells with the selective PRMT5 inhibitor, HLCL65, arrested activation-induced T cell proliferation at the G1 stage of the cell cycle, suggesting PRMT5 promotes cell cycle progression in CD4+ T cells. The Cyclin E1/Cdk2 pair promoting G1/S progression was also decreased after PRMT5 inhibition, as was the phosphorylation of retinoblastoma. In the SJL mouse relapsing-remitting model of MS, the highest PRMT5 expression in central nervous system-infiltrating cells corresponded to peak and relapse timepoints. PRMT5 expression also positively correlated with increasing CD4 Th cell composition, disease severity and Cyclin E1 expression. These data indicate that PRMT5 promotes G1/S cell cycle progression and suggest that this effect influences disease severity and/or progression in the animal model of MS. Modulating PRMT5 levels may be useful for controlling T cell expansion in T cell-mediated diseases including MS.

Nicotinamide nucleotide transhydrogenase expression analysis in multiple sclerosis patients.

Background: Nicotinamide nucleotide transhydrogenase (NNT) is a mitochondrial redox-induced proton pump that links NADPH synthesis to the mitochondrial metabolic pathway. It also participates in the regulation of immune responses. A long non-coding RNA namely NNT-antisense 1 (NNT-AS1) has been shown to be transcribed from the same locus and exert anti-proliferative effects in some tissues. Methods: In the current study, we evaluated expression of NNT and NNT-AS1 in peripheral blood of 50 relapsing-remitting multiple sclerosis patients compared with healthy subjects. The difference in NNT expression was significant in only in male subjects aged over 50 when compared with the corresponding control subgroup. Results: For NNT-AS1, based on the results of Quantile regression and adjustment of the effects of age and sex as well as the interaction between sex and disease status, no significant difference was found between cases and controls. Moreover, NNT and NNT-AS1 expressions were correlated with age in controls and in female subjects respectively. Conclusion: Finally, we assessed correlations between expressions of these genes and detected significant pairwise correlations between transcript levels of NNT and NNT-AS1 genes in both cases and controls. The current study highlights a gender-specific role for NNT in the pathogenesis of MS.

Serum NADPH oxidase concentrations and the associations with iron metabolism in relapsing remitting multiple sclerosis.

BACKGROUND: Overproduction of reactive oxygen species (ROS) and impaired iron metabolism are considered to be possible factors in the pathogenesis of Multiple sclerosis (MS). Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases are the primary sources of regulated ROS production. The NADPH oxidase (NOX) family consists of seven catalytic homologues, NOX1-5 and two dual oxidases. NOX1 and NOX5 are associated with endothelial dysfunction and inflammation but NOX4 has a protective effect on vascular function. The aims of this study were to investigate the status of NOX1, NOX4 and NOX5 and its relationship with serum iron metabolism biomarkers in relapsing-remitting MS patients. METHODS: The study included 53 RRMS patients and 45 control subjects. Serum NOX1,4,5, ferritin, iron, unbound-iron binding capacity, C-reactive protein (CRP), white blood count (WBC) and erythrocyte sedimentation rate (ESR) levels were measured in all the study subjects. RESULTS: Higher serum NOX5 (p < 0.0001), CRP (p = 0.014), ferritin (p = 0.040) and lower serum NOX4 (p < 0.0001) and iron (p = 0.013) concentrations were found in the patients than in controls. No correlation was found between NOXs, CRP, WBC, ESR and iron metabolism biomarkers in patients. CONCLUSION: Our data suggest that increased NOX5 expression and decreased levels of NOX4 might be related with oxidative stress related vascular changes in MS patients. These findings provide future opportunities to combat MS with separately target individual NOX isoforms.

The value of anti-JCV antibody index assessment in multiple sclerosis patients treated with natalizumab with respect to demographic, clinical and radiological findings.

BACKGROUND: Natalizumab-related progressive multifocal leukoencephalopathy (PML) is associated with the presence of anti-John Cunningham virus (JCV) antibodies. The aim of this investigation was to evaluate the long-term stability of anti-JCV antibody serum levels and their relation to various demographic, clinical and radiological characteristics in patients suffering from multiple sclerosis (MS). METHODS: Seventy-eight relapsing-remitting MS patients treated with natalizumab and evaluated for the presence of serum anti-JCV antibodies over a time period of 1-6 years (3-11 samples) were included in the study. Anti-JCV antibody levels and their changes were correlated with various demographic, clinical and radiological findings. RESULTS: Median follow-up time was 43.5 months, with a median of 5.3 samples available per patient. At baseline, 46 (59%) of the patients were seropositive. During follow-up, anti-JCV antibody status changed from negative to positive or vice versa in 23% of patients. Baseline anti-JCV antibody index correlated positively with age (p = 0.03). PATIENTS: with stable positive anti-JCV antibody index had more T2 hyperintensities (20.2 vs. 13.1; p < 0.007) on cerebral magnetic resonance imaging (MRI) and were also older than the stable negative anti-JCV antibody index group of patients (45.2.vs. 40.3 years; p < 0.01). No significant increase in T2 hyperintensities after seroconversion was revealed. Average duration from beginning of natalizumab therapy to seroconversion (n = 13) was 33 months. Annual seroconversion rate of anti-JCV antibody status was 6.5%. A baseline anti-JCV antibody index of >0.90 (n = 33) predicted stable seropositivity (100%), while baseline anti-JCV antibody index <0.20 did not predicted stable seronegativity (59%). PML was not diagnosed in any of the patients studied during the follow-up. CONCLUSIONS: A positive baseline anti-JCV antibody index of >0.90 predicts stable positive JCV serostatus, in contrast with a baseline anti-JCV antibody index of <0.20, which remained negative in 59% of cases. Stable positive anti-JCV index patients have more MRI T2 hyperintensities and are older compared with stable negative anti-JCV index patients.

Phosphorylated SIRT1 as a biomarker of relapse and response to treatment with glatiramer acetate in multiple sclerosis.

We have previously shown that SIRT1 mRNA expression was significantly lower in relapsing MS patients compared to those in remission. Our goal was to longitudinally investigate the role of active, phosphorylated SIRT1 (p-SIRT1) as a potential biomarker of relapse and predictor for response to glatiramer acetate (GA) treatment in patients with relapsing remitting multiple sclerosis (MS). We also want to investigate the downstream effects of SIRT1 activation by measuring the trimethylation of histone 3 at lysine 9 (H3K9me3). A cohort of 15 GA-treated patients was clinically monitored using the Expanded Disability Status Scale (EDSS) and peripheral blood mononuclear cells (PBMCs) were collected at 0, 3, 6, and 12 months after initiation of the therapy. P-SIRT1 and H3K9me3 levels were assayed by Western blotting using specific antibodies. Statistically significant lower levels of p-SIRT1 protein (p < 0.0001) and H3K9me3 (p = 0.001) were found during relapses when compared to stable MS patients. Non-responders to GA treatment were defined as patients who exhibited at least two relapses following initiation of GA treatment. Statistically significant lower levels of p-SIRT1 protein (p = 0.02) and H3K9me3 (p = 0.004) were found in GA non-responders compared to responders. Using receiver operating characteristic analysis, area under the curve (AUC) for p-SIRT1 was 77% (p = 0.007) and for H3K9me3 was 81% (p = 0.002) for prediction of relapse. For predicting responsiveness to GA treatment, AUC was 75% (P = 0.01) for H3K9me3. Our data suggest that p-SIRT1 and H3K9me3 could serve as potential biomarkers for MS relapse. In addition, H3K9me3 could serve as possible biomarker to predict response to GA treatment.

Effect of fish and olive oil on mitochondrial ATPase activity and membrane fluidity in patients with relapsing-remitting multiple sclerosis treated with interferon beta 1-b.

BACKGROUND: Multiple sclerosis (MS) is an inflammatory disease of the central nervous system associated with increased oxidative stress (OS) and mitochondrial alterations. Fish oil consumption has neuroprotective, antioxidant and anti-inflammatory effects in patients with relapsing-recurrent MS (RR-MS). OBJECTIVE: To evaluate changes in the hydrolytic activity of ATP synthase and mitochondrial membrane fluidity in patients with RR-MS who receive fish oil or olive oil as a dietary supplement. METHODS: Clinical, controlled, randomized, double-blind trial. Patients consumed fish oil or olive oil for one year. The hydrolytic activity of ATPase and the fluidity of the mitochondrial membrane of platelets were quantified. RESULTS: In patients with RR-MS, a decrease in the fluidity of mitochondrial membranes and an increase in the hydrolytic activity of ATP synthase was observed in comparison with healthy controls. After 6 or 9 months of treatment with fish oil or olive oil, respectively, these values were normalized. CONCLUSION: The consumption of fish oil and olive oil increases the fluidity of the mitochondrial membranes and decreases the catabolic activity of ATP synthase in platelets from patients with RR-MS.

Dysregulated Homeostasis of Acetylcholine Levels in Immune Cells of RR-Multiple Sclerosis Patients.

Multiple sclerosis (MS) is characterized by pro-inflammatory cytokine production. Acetylcholine (ACh) contributes to the modulation of central and peripheral inflammation. We studied the homeostasis of the cholinergic system in relation to cytokine levels in immune cells and sera of relapsing remitting-MS (RR-MS) patients. We demonstrated that lower ACh levels in serum of RR-MS patients were inversely correlated with the increased activity of the hydrolyzing enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Interestingly, the expression of the ACh biosynthetic enzyme and the protein carriers involved in non-vesicular ACh release were found overexpressed in peripheral blood mononuclear cells of MS patients. The inflammatory state of the MS patients was confirmed by increased levels of TNFα, IL-12/IL-23p40, IL-18. The lower circulating ACh levels in sera of MS patients are dependent on the higher activity of cholinergic hydrolyzing enzymes. The smaller ratio of ACh to TNFα, IL-12/IL-23p40 and IL-18 in MS patients, with respect to healthy donors (HD), is indicative of an inflammatory environment probably related to the alteration of cholinergic system homeostasis.

Rhabdomyolysis following interferon-beta treatment in a patient with multiple sclerosis - A case report.

BACKGROUND: Multiple sclerosis is an inflammatory disease of the central nervous system for which there is currently no cure. Interferon-beta-1-alpha is worldwide one of the most widely used treatments in multiple sclerosis. To our knowledge there is one previous reported case of rhabdomyolysis associated with Interferon-beta treatment. CASE PRESENTATION: We describe a 30 year old man with relapsing remitting multiple sclerosis who developed rhabdomyolysis and increased creatine kinase following Interferon-beta-1-alpha therapy. After the medication was discontinued, the patient rapidly improved. CONCLUSION: Clinicians should be aware of the possibility of rhabdomyolysis occurring during Interferon-beta-1-alpha therapy. In cases where patients complain of severe myalgia, and in particular if weakness is reported, creatine kinase activity should be measured to prevent irreversible rhabdomyolysis during Interferon-beta-1-alpha therapy in patients with multiple sclerosis.

Analysis of MMP2-1306C/T and TIMP2G-418C polymorphisms with relapsing remitting multiple sclerosis.

AIMS: Multiple sclerosis (MS) is an autoimmune, inflammatory disease characterized by loss of myelin forming oligodendrocytes and changes in the blood-brain barrier. Matrix metalloproteinase (MMP) -2 and -9 are known to cause disruption of the blood-brain barrier, remodeling of the basal lamina, regeneration of axons, and remyelination in MS. The imbalance between MMPs and tissue inhibitor metalloproteinases (TIMPs) may lead to the emergence of pathological processes such as MS. The roles of MMP2-1306 C/T and TIMP2-418 G/C genetic variants in MS have not been studied before. We aimed to investigate whether MMP2-1306C/T and TIMP2-418 G/C gene variants are risk factors for patients with relapsing remitting multiple sclerosis (RRMS). METHODS: The study included 102 RRMS and 102 healthy controls. Genomic DNA was extracted from peripheral leukocytes from ethylenediaminetetraacetic acid anticoagulated blood. Genotyping of the MMP2-1306C/T and TIMP2G-418C polymorphisms was performed using real-time PCR. RESULTS: There were significant differences in terms of distribution of genotype (MMP2-1306- CT, TT) and T allele frequency between the patients with RRMS and the control group (p<0.0001; p<0.0001). The groups were not different in terms of TIMP2G-418C polymorphisms. CONCLUSIONS: In the RRMS group, the genotype and allele frequencies of MMP2-1306C/T polymorphism showed significant differences from the controls. These results indicate that MMP2 might play a role in the pathogenesis of MS even during the inflammation stage.

The IFN-ß 1b effect on Cu Zn superoxide dismutase (SOD1) in peripheral mononuclear blood cells of relapsing-remitting multiple sclerosis patients and in neuroblastoma SK-N-BE cells.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease leading to axonal injury. Even if the etiology of MS is still unknown the disease begins with inflammation involving autoreactive T lymphocytes activation in genetically susceptible subjects. Interferon beta-1b (IFN ß 1b) is one of the most used drug in the MS therapy. The results obtained in this study show that the concentration of SOD1 in CSF of relapsing-remitting MS (RR-MS) patients, evaluated by enzyme-linked immunosorbent assay (ELISA), is decreased compared to pathological controls. Moreover, the Western blotting analysis demonstrated that SOD1 in human peripheral blood mononuclear cells (PBMC) in healthy controls was significantly higher compared to MS subjects before starting DMT therapy. In addition IFN ß 1b therapy causes an increase of intracellular SOD1 protein as well as mRNA levels in PBMC. Moreover, the treatment of neuroblastoma SK-N-BE cells with IFN ß 1b increased SOD1 protein and mRNA levels; these data also suggest that neuroprotective effect of this physiological molecule is, at least in part, carried out through its effect on SOD1. This study demonstrate that DMT therapy is able to increase SOD1 expression in PBMC of RR-MS patients. Therefore, the effectiveness of DMT therapy can be ascribed, at least in part, to an increased levels of this antioxidant enzyme as further confirmed by in vitro studies in SK-N-BE cells.

Indoleamine 2,3 Dioxygenase (IDO) Expression and Activity in Relapsing-Remitting Multiple Sclerosis.

BACKGROUND: Interferon gamma (IFN-γ) production induces the transcription of indoleamine 2,3 dioxygenase (IDO) resulting in the reduction of T-cell activation and proliferation through the depletion of tryptophan and the elicitation of Treg lymphocytes. IDO was shown to be involved in the pathogenesis of autoimmune diseases; we investigated whether changes in IDO gene expression and activity could be indicative of onset of relapse in multiple sclerosis (MS) patients. METHODS: IDO and interferon-γ (IFN-γ) gene expression, serum IDO activity (Kynurenine/Tryptophan ratio) and serum neopterin concentration--a protein released by macrophages upon IFN-γ stimulation--were measured in 51 individuals: 36 relapsing remitting (RR)-MS patients (21 in acute phase--AMS, 15 in stable phase--SMS) and 15 healthy controls (HC). PBMCs samples in AMS patients were collected before (BT-AMS) and during glucocorticoids-based therapy (DT-AMS). RESULTS: IDO expression was increased and IFN-γ was decreased (p<0.001) in BT-AMS compared to SMS patients. Glucocorticoids-induced disease remission resulted in a significant reduction of IDO and IFN-γ gene expression, IDO catalytic activity (p<0.001). Serum neopterin concentration followed the same trend as IDO expression and activity. CONCLUSIONS: Measurement of IDO gene expression and activity in blood could be a useful marker to monitor the clinical course of RR-MS. Therapeutic interventions modulating IDO activity may be beneficial in MS.

The p38 mitogen-activated protein kinase cascade modulates T helper type 17 differentiation and functionality in multiple sclerosis.

The p38 mitogen-activated protein kinase cascade is required for the induction of a T helper type 17 (Th17) -mediated autoimmune response, which underlies the development and progression of several autoimmune diseases, such as experimental autoimmune encephalomyelitis, the animal model of multiple sclerosis (MS). However, the contribution of p38 phosphorylation to human Th cell differentiation has not been clarified. Here we demonstrate that the p38 signalling pathway is implicated in the generation of Th17 lymphocytes from human CD4(+)  CD27(+)  CD45RA(+) naive T cells, both in healthy donors and in patients affected by the relapsing-remitting form of MS. Our data also indicate that p38 activation is essential for interleukin-17 release from central memory lymphocytes and committed Th17 cell clones. Furthermore, CD4(+) T cells isolated from individuals with relapsing-remitting MS display an altered responsiveness of the p38 cascade, resulting in increased p38 phosphorylation upon stimulation. These findings suggest that the p38 signalling pathway, by modulating the Th17 differentiation and response, is involved in the pathogenesis of MS, and open new perspectives for the use of p38 inhibitors in the treatment of Th17-mediated autoimmune diseases.

TIMP-1 resistant matrix metalloproteinase-9 is the predominant serum active isoform associated with MRI activity in patients with multiple sclerosis.

BACKGROUND: The activity of matrix metalloproteinase-9 (MMP-9) depends on two isoforms, an 82 kDa active MMP-9 modulated by its specific tissue inhibitor (TIMP-1), and a 65 kDa TIMP-1 resistant active MMP-9. The relevance of these two enzymatic isoforms in multiple sclerosis (MS) is still unknown. OBJECTIVE: To investigate the contribution of the TIMP-1 modulated and resistant active MMP-9 isoforms to MS pathogenesis. METHODS: We measured the serum levels of the 82 kDa and TIMP-1 resistant active MMP-9 isoforms by activity assay systems in 86 relapsing-remitting MS (RRMS) patients, categorized according to clinical and magnetic resonance imaging (MRI) evidence of disease activity, and in 70 inflammatory (OIND) and 69 non-inflammatory (NIND) controls. RESULTS: Serum levels of TIMP-1 resistant MMP-9 were more elevated in MS patients than in OIND and NIND (p < 0.05, p < 0.02, respectively). Conversely, 82 kDa active MMP-9 was higher in NIND than in the OIND and MS patients (p < 0.01 and p < 0.00001, respectively). MRI-active patients had higher levels of TIMP-1 resistant MMP-9 and 82 kDa active MMP-9, than did those with MRI inactive MS (p < 0.01 and p < 0.05, respectively). CONCLUSION: Our findings suggested that the TIMP-1 resistant MMP-9 seem to be the predominantly active isoform contributing to MS disease activity.

Increased microglial catalase activity in multiple sclerosis grey matter.

Chronic demyelination, on-going inflammation, axonal loss and grey matter neuronal injury are likely pathological processes that contribute to disease progression in multiple sclerosis (MS). Although the precise contribution of each process and their aetiological substrates is not fully known, recent evidence has implicated oxidative damage as a major cause of tissue injury in MS. The degree of tissue injury caused by oxidative molecules, such as reactive oxygen species (ROS), is balanced by endogenous anti-oxidant enzymes which detoxify ROS. Understanding endogenous mechanisms which protect the brain against oxidative injury in MS is important, since enhancing anti-oxidant responses is a major therapeutic strategy for preventing irreversible tissue injury in the disease. Our aims were to determine expression and activity levels of the hydrogen peroxide-reducing enzyme catalase in MS grey matter (GM). In MS GM, a catalase enzyme activity was elevated compared to control GM. We measured catalase protein expression by immune dot-blotting and catalase mRNA by a real-time polymerase chain reaction (RT-PCR). Protein analysis studies showed a strong positive correlation between catalase and microglial marker IBA-1 in MS GM. In addition, calibration of catalase mRNA level with reference to the microglial-specific transcript AIF-1 revealed an increase in this transcript in MS. This was reflected by the extent of HLA-DR immunolabeling in MS GM which was significantly elevated compared to control GM. Collectively, these observations provide evidence that microglial catalase activity is elevated in MS grey matter and may be an important endogenous anti-oxidant defence mechanism in MS.

Secretory phospholipase A2 activity in serum and cerebrospinal fluid of patients with relapsing-remitting multiple sclerosis.

An increasing body of evidence suggests that patients afflicted with multiple sclerosis (MS) show alterations in immunologic markers including increases in proinflammatory cytokine activity and inflammation. Secretory Phospholipase A2 (sPLA2) is one of the key molecules contributing to the production of inflammatory lipid mediators, mainly eicosanoids. They are considered proinflammatory enzymes and their inhibition has long been recognized as a desirable therapeutic target. The aim of this study was to measure the enzyme activity of sPLA2 both in serum and cerebrospinal fluid (CSF) of MS patients. Twenty MS patients accompanied with 20 age-sex matched controls were recruited. The results showed that the enzyme activity of serum sPLA2 was 0.007±0.021 (µmol/min/ml) in MS patients vs. 0.007±0.016 (µmol/min/ml) in patients with other neurological diseases as a control group (P=0.5). Our findings also indicated that there is no correlation (P=0.6) between CSF sPLA2 enzyme activity and MS disease when the results of two groups were compared (0.072±0.020 in cases vs. 0.071±0.01 in control group). The results suggest that the enzyme activity of sPLA2 is not altered during the disease course.

Serum paraoxonase and arylesterase activity and oxidative status in patients with multiple sclerosis.

The aim of this study was to investigate serum paraoxonase and arylesterase activities, and to determine oxidative status via the measurement of total oxidant status (TOS), total antioxidant status (TAS) and the oxidative stress index (OSI) in patients with relapsing-remitting multiple sclerosis (RRMS). Results were compared with data from healthy controls. A total of 60 subjects, including 30 newly diagnosed and untreated patients with RRMS (20 females, 10 males, 18-40 years of age) and 30 healthy controls (20 female, 10 male 20-40 years of age) were enrolled in this study. The oxidative status of the RRMS patients was measured by TOS, TAS and estimation of the OSI was made by a new automated method. Paraoxonase (PON1) and arylesterase activities were measured spectrophotometrically. TAS levels of RRMS patients were significantly lower than that of controls (p < 0.05). TOS levels of RRMS patients were higher than that of controls (p < 0.05). PON1 and arylesterase activities of RRMS patients were lower, but not significantly, than those of controls (p > 0.05). There was no correlation between serum PON1 activity and OSI in patients with RRMS (p > 0.05). Hypercholesterolemia was not observed in multiple sclerosis patients. In conclusion, although the mechanism underlying the significant reduction of TAS levels of multiple sclerosis patients compared with those of controls is unknown, the results imply that endogenous antioxidants may have been exhausted by increased oxidative stress and we believe that additional antioxidant treatment might be beneficial for these patients.

Roles of the ubiquitin peptidase USP18 in multiple sclerosis and the response to interferon-ß treatment.

BACKGROUND AND PURPOSE: Ubiquitin specific peptidase 18 (USP18) is a deubiquitinating enzyme that functions as a negative regulator of the type I interferon (IFN) signalling pathway and is specifically induced by type I IFNs. In the present study, previous observations by our group were expanded suggesting an implication of USP18 in multiple sclerosis (MS) based on the finding of a deficient expression of the gene in peripheral blood mononuclear cells from MS patients compared with healthy controls. METHODS: Two polymorphisms, rs2542109 (intronic) and rs9618216 (promoter), were genotyped in a cohort of 691 relapse-onset MS patients and 1028 healthy controls and in 225 MS patients treated with IFNß and classified into responders and non-responders after 2 years of treatment according to clinical criteria. Correlations between genotypes and expression levels for USP18 and its target ISG15 were performed by real-time polymerase chain reaction. RESULTS: Two USP18 haplotypes were significantly associated with MS, TG and CG. Additional experiments revealed that CG carriers were characterized by lower USP18 gene expression levels in peripheral blood mononuclear cells and higher clinical disease activity. Finally, AA homozygosis for the intronic polymorphism rs2542109 was associated with the responder phenotype; however, USP18 expression levels induced by IFNß did not differ amongst MS patients carrying different rs2542109 genotypes. CONCLUSIONS: Altogether, these results point to a role of USP18 in MS pathogenesis and the therapeutic response to IFNß.