Silva Markovic-Plese

Oral simvastatin treatment in relapsing-remitting multiple sclerosis.

Many drugs have been approved for relapsing forms of multiple sclerosis but are only partly effective, are injected, and are expensive. We aimed to investigate use of of oral simvastatin (80 mg) in 30 individuals with relapsing-remitting multiple sclerosis. The mean number of gadolinium-enhancing lesions at months 4, 5, and 6 of treatment was compared with the mean number of lesions noted on pretreatment brain MRI scans. Number and volume of Gd-enhancing lesions declined by 44%, (p<0.0001) and 41% (p=0.0018), respectively. Treatment was well tolerated. Oral simvastatin might inhibit inflammatory components of multiple sclerosis that lead to neurological disability.

IFN-β Inhibits Human Th17 Cell Differentiation

IFN-β-1a has been used over the past 15 years as a primary therapy for relapsing-remitting multiple sclerosis (MS). However, the immunomodulatory mechanisms that provide a therapeutic effect against this CNS inflammatory disease are not yet completely elucidated. The effect of IFN-β-1a on Th17 cells, which play a critical role in the development of the autoimmune response, has not been extensively studied in humans. We have investigated the effect of IFN-β-1a on dendritic cells (DCs) and naive CD4+CD45RA+ T cells derived from untreated MS patients and healthy controls in the context of Th17 cell differentiation. We report that IFN-β-1a treatment down-regulated the expression of IL-1β and IL-23p19 in DCs, whereas it induced the gene expression of IL-12p35 and IL-27p28. We propose that IFN-β-1a-mediated up-regulation of the suppressor of cytokine signaling 3 expression, induced via STAT3 phosphorylation, mediates IL-1β and IL-23 down-regulation, while IFN-β-1a-induced STAT1 phosphorylation induces IL-27p28 expression. CD4+CD45RA+ naive T cells cocultured with supernatants from IFN-β-1a-treated DCs exhibited decreased gene expression of the Th17 cell markers retinoic acid-related orphan nuclear hormone receptor c (RORc), IL-17A, and IL-23R. A direct IFN-β-1a treatment of CD45RA+ T cells cultured in Th17-polarizing conditions also down-regulated RORc, IL-17A, and IL-23R, but up-regulated IL-10 gene expression. Studies of the mechanisms involved in the Th17 cell differentiation suggest that IFN-β-1a inhibits IL-17 and induces IL-10 secretion via activated STAT1 and STAT3, respectively. IFN-β’s suppression of Th17 cell differentiation may represent its most relevant mechanism of selective suppression of the autoimmune response in MS.

Simvastatin Inhibits IL-17 Secretion by Targeting Multiple IL-17-Regulatory Cytokines and by Inhibiting the Expression of IL-17 Transcription Factor RORC in CD4+ Lymphocytes

Statins, extensively used as cholesterol-lowering agents, have recently been identified as immunomodulatory agents. This study investigated the statins’ mechanisms that target the autoimmune response in humans, and evaluated their therapeutic potential in multiple sclerosis. Our results demonstrated statin-mediated increases in suppressor of cytokine secretion (SOCS) 3 and suppressor of cytokine secretion 7, which negatively regulate the STAT/JAK signal transduction pathway and IL-6 and IL-23 gene expression in monocytes. Simvastatin also induced IFN-γ, IL-4, and IL-27 production in monocytes, which together inhibited IL-17 transcription and secretion in CD4+ T cells. IL-17-producing CD4+ cells, referred to as Th17 cells, have recently been found to play a central role in the development of autoimmune diseases. Furthermore, simvastatin directly inhibited the expression of retinoic acid-related orphan nuclear hormone receptor C, a transcription factor that controls IL-17 production in CD4+ T cells. This effect was reversed by mevalonic acid, a downstream metabolite of 3-hydroxy-3-methylglutaryl CoA reductase, confirming that simvastatin’s specific effect is through the inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase. These results provide evidence for the novel immunomodulatory mechanisms of statins, which selectively target the regulation of cytokine transcription involved in the development of the human autoimmune response. Based on the described immunomodulatory mechanisms, good safety profile and oral bioavailability, statins represent a promising therapeutic approach for multiple sclerosis and other chronic inflammatory diseases.

Oligoclonal myelin-reactive T-cell infiltrates derived from multiple sclerosis lesions are enriched in Th17 cells.

In this study, acute and chronic brain and spinal cord lesions, and normal appearing white matter (NAWM), were resected post-mortem from a patient with aggressive relapsing-remitting multiple sclerosis (MS). T-cell infiltrates from the central nervous system (CNS) lesions and NAWM were separated and characterized in-vitro. All infiltrates showed a proliferative response against multiple myelin peptides. Studies of the T-cell receptor (TCR)Vbeta and Jbeta usage revealed a very skewed repertoire with shared complementarity-determining region (CDR)3 lengths detected in all CNS lesions and NAWM. In the acute lesion, genomic profiling of the infiltrating T-cells revealed up-regulated expression of TCRalpha and beta chain, retinoic acid-related orphan nuclear hormone receptor C (RORC) transcription factor, and multiple cytokine genes that mediate Th17 cell expansion. The differentially expressed genes involved in regulation of Th17 cells represent promising targets for new therapies of relapsing-remitting MS.

IFN-β1a Inhibits the Secretion of Th17-Polarizing Cytokines in Human Dendritic Cells via TLR7 Up-Regulation

IFN-β, an effective therapy against relapsing-remitting multiple sclerosis, is naturally secreted during the innate immune response against viral pathogens. The objective of this study was to characterize the immunomodulatory mechanisms of IFN-β targeting innate immune response and their effects on dendritic cell (DC)-mediated regulation of T cell differentiation. We found that IFN-β1a in vitro treatment of human monocyte-derived DCs induced the expression of TLR7 and the members of its downstream signaling pathway, including MyD88, IL-1R-associated kinase 4, and TNF receptor-associated factor 6, while it inhibited the expression of IL-1R. Using small interfering RNA TLR7 gene silencing, we confirmed that IFN-β1a-induced changes in MyD88, IL-1R-associated kinase 4, and IL-1R expression were dependent on TLR7. TLR7 expression was also necessary for the IFN-β1a-induced inhibition of IL-1β and IL-23 and the induction of IL-27 secretion by DCs. Supernatant transfer experiments confirmed that IFN-β1a-induced changes in DC cytokine secretion inhibit Th17 cell differentiation as evidenced by the inhibition of retinoic acid-related orphan nuclear hormone receptor C and IL-17A gene expression and IL-17A secretion. Our study has identified a novel therapeutic mechanism of IFN-β1a that selectively targets the autoimmune response in multiple sclerosis.

Pathogenic features of CD4+CD28- T cells in immune disorders

Aging of the immune system contributes to the increased morbidity and mortality of the elderly population and may occur prematurely in patients with immune disorders. One of the main characteristics of immunosenescence is the expansion of CD4(+)CD28(-) T cells in the blood. These cells are effector memory T cells with cytotoxic capacity, and have been recently described to have pathogenic potential in a variety of immune disorders. Interestingly, CD4(+)CD28(-) T cells have now been found to infiltrate target tissues of patients with multiple sclerosis, rheumatoid arthritis, myopathies, acute coronary syndromes, and other immune-related diseases. In this review, we discuss potential factors and mechanisms that may induce the expansion of these cells, as well as their putative pathogenic mechanisms in immune disorders.

B Cells as a Therapeutic Target for IFN-β in Relapsing–Remitting Multiple Sclerosis

IFN-β-1b is a first-line immunomodulatory therapy for relapsing–remitting multiple sclerosis (RR MS). However, its effects on B cells have not been characterized. In vitro studies of B cells derived from RR MS patients revealed that IFN-β-1b decreases B cells’ stimulatory capacity, as detected by inhibition of the Ag-specific T cell proliferative response upon Ag presentation by IFN-β-1b–treated B cells. Our study has identified that IFN-β-1b inhibited B cells’ stimulatory capacity in RR MS patients and healthy controls through the suppression of CD40 and CD80 expression, whereas the MHC class I and II expression was not changed. IFN-β-1b in vitro treatment inhibited B cell secretion of IL-1β and IL-23 and induced IL-12 and IL-27. Supernatants transferred from IFN-β-1b–treated B cells inhibited Th17 cell differentiation, as they suppressed gene expression of the retinoic acid-related orphan nuclear hormone receptor C and IL-17A and secretion of IL-17A. In addition, IFN-β-1b induced B cells’ IL-10 secretion, which may mediate their regulatory effect. Studies of B cells derived from RR MS patients treated with recombinant s.c. injected IFN-β-1b revealed that they induced a significantly lower proliferative response in allogenic MLR than the B cells from untreated patients. Further confirming the IFN-β-1b in vitro-induced changes in B cell cytokine secretion, B cells derived from the IFN-β-1b–treated patients secreted significantly lower levels of IL-1β and IL-23 and higher levels of IL-12 and IL-27 in comparison with the B cells derived from untreated patients. We conclude that IFN-β-1b exerts its therapeutic effects in part by targeting B cells’ functions that contribute to the autoimmune pathogenesis of RR MS.

Self-complementary AAV virus (scAAV) safe and long-term gene transfer in the trabecular meshwork of living rats and monkeys.

PURPOSE AAV vectors produce stable transgene expression and elicit low immune response in many tissues. AAVs have been the vectors of choice for gene therapy for the eye, in particular the retina. scAAVs are modified AAVs that bypass the required second-strand DNA synthesis to achieve transcription of the transgene. The goal was to investigate the ability of AAV vectors to induce long-term, safe delivery of transgenes to the trabecular meshwork of living animals. METHODS Single doses of AAV2.GFP and AAV2.RGD.GFP/Ad5.LacZ were injected intracamerally (IC) into rats (n = 28 eyes). A single dose of scAAV.GFP was IC-injected into rats (n = 72 eyes) and cynomolgus monkeys (n = 3). GFP expression was evaluated by fluorescence, immunohistochemistry, and noninvasive gonioscopy. Intraocular pressure (IOP) was measured with calibrated tonometer (rats) and Goldmann tonometer (monkeys). Differential expression of scAAV-infected human trabecular meshwork cells (HTM) was determined by microarrays. Humoral and cell-mediated immune responses were evaluated by ELISA and peripheral blood proliferation assays. RESULTS No GFP transduction was observed on the anterior segment tissues of AAV-injected rats up to 27 days after injection. In contrast, scAAV2 transduced the trabecular meshwork very efficiently, with a fast onset (4 days). Eyes remained clear and no adverse effects were observed. Transgene expression lasted >3.5 months in rats and >2.35 years in monkeys. CONCLUSIONS The scAAV viral vector provides prolonged and safe transduction in the trabecular meshwork of rats and monkeys. The stable expression and safe properties of this vector could facilitate the development of trabecular meshwork drugs for gene therapy for glaucoma.

Diffusion tensor imaging based network analysis detects alterations of neuroconnectivity in patients with clinically early relapsing‐remitting multiple sclerosis

Although it is inarguable that conventional MRI (cMRI) has greatly contributed to the diagnosis and assessment of multiple sclerosis (MS), cMRI does not show close correlation with clinical findings or pathologic features, and is unable to predict prognosis or stratify disease severity. To this end, diffusion tensor imaging (DTI) with tractography and neuroconnectivity analysis may assist disease assessment in MS. We, therefore, attempted this pilot study for initial assessment of early relapsing‐remitting MS (RRMS). Neuroconnectivity analysis was used for evaluation of 24 early RRMS patients within 2 years of presentation, and compared to the network measures of a group of 30 age‐and‐gender‐matched normal control subjects. To account for the situation that the connections between two adjacent regions may be disrupted by an MS lesion, a new metric, network communicability, was adopted to measure both direct and indirect connections. For each anatomical area, the brain network communicability and average path length were computed and compared to characterize the network changes in efficiencies. Statistically significant (P < 0.05) loss of communicability was revealed in our RRMS cohort, particularly in the frontal and hippocampal/parahippocampal regions as well as the motor strip and occipital lobes. Correlation with the 25‐foot Walk test with communicability measures in the left superior frontal (r = −0.71) as well as the left superior temporal gyrus (r = −0.43) and left postcentral gyrus (r = −0.41) were identified. Additionally identified were increased communicability between the deep gray matter structures (left thalamus and putamen) with the major interhemispheric and intrahemispheric white matter tracts, the corpus callosum, and cingulum, respectively. These foci of increased communicability are thought to represent compensatory changes. The proposed DTI‐based neuroconnectivity analysis demonstrated quantifiable, structurally relevant alterations of fiber tract connections in early RRMS and paves the way for longitudinal studies in larger patient groups. Hum Brain Mapp 34:3376–3391, 2013.

Neuromyelitis optica lesions may inform multiple sclerosis heterogeneity debate

Neuromyelitis optica (NMO) and multiple sclerosis (MS) are considered inflammatory demyelinating diseases with distinguishing pathological characteristics. NMO pathology shows perivascular immunoglobulin G and complement deposition, as well as an astrocytopathy with aquaporin‐4 (AQP4) loss. MS lesions reveal a profound, interindividual heterogeneity in immunopathological patterns of active demyelination, which has been challenged by the description of stage‐dependent sequences of pathological features. The aim of our study was to compare the histological characteristics of early active demyelinating NMO and MS brain lesions.