Intestinal Permeability in Relapsing-Remitting Multiple Sclerosis

Changes of intestinal permeability (IP) have been extensively investigated in inflammatory bowel diseases (IBD) and celiac disease (CD), underpinned by a known unbalance between microbiota, IP and immune responses in the gut. Recently the influence of IP on brain function has greatly been appreciated. Previous works showed an increased IP that preceded experimental autoimmune encephalomyelitis development and worsened during disease with disruption of TJ. Moreover, studying co-morbidity between Crohn's disease and MS, a report described increased IP in a minority of cases with MS. In a recent work we found that an alteration of IP is a relatively frequent event in relapsing-remitting MS, with a possible genetic influence on the determinants of IP changes (as inferable from data on twins); IP changes included a deficit of the active mechanism of absorption from intestinal lumen. The results led us to hypothesize that gut may contribute to the development of MS, as suggested by another previous work of our group: a population of CD8+CD161high T cells, belonging to the mucosal-associated invariant T (MAIT) cells, a gut- and liver-homing subset, proved to be of relevance for MS pathogenesis. We eventually suggest future lines of research on IP in MS: studies on IP changes in patients under first-line oral drugs may result useful to improve their therapeutic index; correlating IP and microbiota changes, or IP and blood-brain barrier changes may help clarify disease pathogenesis; exploiting the IP data to disclose co-morbidities in MS, especially with CD and IBD, may be important for patient care.

A staged screening of registered drugs highlights remyelinating drug candidates for clinical trials

There is no treatment for the myelin loss in multiple sclerosis, ultimately resulting in the axonal degeneration that leads to the progressive phase of the disease. We established a multi-tiered platform for the sequential screening of drugs that could be repurposed as remyelinating agents. We screened a library of 2,000 compounds (mainly Food and Drug Administration (FDA)-approved compounds and natural products) for cellular metabolic activity on mouse oligodendrocyte precursors (OPC), identifying 42 molecules with significant stimulating effects. We then characterized the effects of these compounds on OPC proliferation and differentiation in mouse glial cultures, and on myelination and remyelination in organotypic cultures. Three molecules, edaravone, 5-methyl-7-methoxyisoflavone and lovastatin, gave positive results in all screening tiers. We validated the results by retesting independent stocks of the compounds, analyzing their purity, and performing dose-response curves. To identify the chemical features that may be modified to enhance the compounds' activity, we tested chemical analogs and identified, for edaravone, the functional groups that may be essential for its activity. Among the selected remyelinating candidates, edaravone appears to be of strong interest, also considering that this drug has been approved as a neuroprotective agent for acute ischemic stroke and amyotrophic lateral sclerosis in Japan.

IFN-β and multiple sclerosis: from etiology to therapy and back

Several immunomodulatory treatments are currently available for relapsing-remitting forms of multiple sclerosis (RRMS). Interferon beta (IFN) was the first therapeutic intervention able to modify the course of the disease and it is still the most used first-line treatment in RRMS. Though two decades have passed since IFN-β was introduced in the management of MS, it remains a valid approach because of its good benefit/risk profile. This is witnessed by new efforts of pharmaceutical industry to improve this line: a PEGylated form of subcutaneous IFN-β 1a, (Plegridy(®)) with a longer half-life, has been recently approved in RRMS. This review will survey the various stages of the use of type I IFN in MS, with special attention to the effect of the treatment on the supposed viral etiologic factors associated to the disease. The antiviral activities of IFN (that initially prompted its use as immunomodulatory agent in MS), and the mounting evidences in favor of a viral etiology in MS, allowed us to outline a re-appraisal from etiology to therapy and back.

TET2 gene expression and 5-hydroxymethylcytosine level in multiple sclerosis peripheral blood cells

Aberrant DNA methylation can lead to genome destabilization and to deregulated gene expression. Recently, 5-hydroxymethylcytosine (5hmC), derived from oxidation of 5-methylcytosine (5mC) by the Ten-Eleven Translocation (TET) enzymes, has been detected. 5hmC is now considered as a new epigenetic DNA modification with relevant roles in cell homeostasis regulating DNA demethylation and transcription. Our aim was to investigate possible changes in the DNA methylation/demethylation machinery in MS. We assessed the expression of enzymes involved in DNA methylation/demethylation in peripheral blood mononuclear cells (PBMCs) from 40 subjects with MS and 40 matched healthy controls. We performed also, DNA methylation analysis of specific promoters and analysis of global levels of 5mC and 5hmC. We show that TET2 and DNMT1 expression is significantly down-regulated in MS PBMCs and it is associated with aberrant methylation of their promoters. Furthermore, 5hmC is decreased in MS PBMCs, probably as a result of the diminished TET2 level.

Epstein-Barr virus nuclear antigen-1 B-cell epitopes in multiple sclerosis twins

BACKGROUND

Compared with quantitative observations, the search for qualitative changes that may characterize the immune response to Epstein-Barr virus (EBV) in multiple sclerosis (MS) has been less intense.

OBJECTIVE

To examine the B-cell epitopes of antibodies against the Epstein-Barr nuclear antigen-1 (EBNA-1) and their relevance for MS, through a study in disease-discordant identical twins.

METHODS

We evaluated the antibodies to all unique, maximally overlapping octapeptides of EBNA-1 in 12 pairs of monozygotic (MZ) twins (9 MS-discordant, 3 healthy), 3 non-twin patients and 2 healthy subjects. All except one of the patients were untreated. The EBV serology of these individuals had been assessed in advance using commercially available and in-house enzyme-linked immunosorbent assay (ELISA) kits, including assays for antibodies against select peptides of EBNA-1: EBNA-72 (GAGGGAGAGG) and EBNA-206 (EADYFEYHQEGGPDGE).

RESULTS

The glycine-alanine rich domain of EBNA-1 was immunodominant in all subjects. Compared with healthy individuals, and similarly to what has been described in infectious mononucleosis (IM) patients, affected co-twins and non-twin patients had a significantly increased response to another EBNA-1 epitope (aa. 401-411).

CONCLUSION

In a study that controls for confounders, our data focus an EBNA-1 specificity that may be associated with MS pathogenesis.

Multiple sclerosis: pharmacogenomics and personalised drug treatment

Multiple sclerosis (MS) is a disorder of the central nervous system with an inflammatory and a neurodegenerative component. We do not yet have a definitive therapy for MS. Attempts to develop new treatments are long and costly and should be paralleled by studies aimed at increasing the therapeutic index of the existing treatments, interferon beta and glatiramer acetate. Pharmacogenetics and pharmacogenomics may be of use in this respect though their application may not be straightforward, particularly in MS.