Clinical response to Nabiximols correlates with the downregulation of immune pathways in multiple sclerosis.

BACKGROUND AND PURPOSE: Nabiximols (Sativex® ) is a cannabinoid-based compound used for the treatment of moderate to severe spasticity in multiple sclerosis (MS). The aim of the study was to investigate the effect of the administration of Nabiximols on blood transcriptome profile of patients with MS and to interpret it in the context of pathways and networks. METHODS: Whole-genome expression profiling was performed in whole blood of 33 subjects with MS at baseline and after 4 weeks of drug treatment. Patients were classified as responders (n = 19) and non-responders (n = 14). Pathway and network analyses on genes modulated by the drug were performed, followed by in vitro stimulation of peripheral blood mononuclear cells with pro-inflammatory agents to support the immunomodulatory properties of the drug. RESULTS: Individual effect size was modest; however, we observed a downregulation of several immune-related pathways after 4 weeks of treatment, which was more pronounced when restricting analyses to responders. Interesting hub molecules functionally related to the immune system emerged from network analysis, including NFKB1, FYN, MAP14 and TP53. The immunomodulatory properties of the drug were confirmed through in vitro assays in peripheral blood mononuclear cells collected from patients with MS. CONCLUSIONS: Our findings support the immunomodulatory activity of cannabinoids in patients with MS. Further studies in more specific cell types are needed to refine these results.

Pharmacogenetic study of long-term response to interferon-ß treatment in multiple sclerosis.

The aim of the study is the identification of genetic factors that influence the long-term response to interferon-ß (IFNß) (4-year follow-up). We performed a genome-wide association study in 337 IFNß-treated Italian multiple sclerosis patients at the extreme of treatment response, and we meta-analyzed association effects, integrating results with pathway analysis, gene-expression profiling of IFNß-stimulated peripheral blood mononuclear cells from 20 healthy controls (HC) and expression quantitative locus (eQTL) analyses. From meta-analysis, 43 markers were associated at P<10-4, and two of them (rs7298096 and rs4726460) pointed to two genes, NINJ2 and TBXAS1, that were significantly downregulated after IFNß stimulation in HC (P=3.1 × 10-9 and 5.6 × 10-10). We also observed an eQTL effect for the allele associated with favorable treatment response (rs4726460A); moreover, TBXAS1 appeared downregulated upon IFNß administration (ß=-0.39; P=0.02). Finally, we found an enrichment of pathways related to inflammatory processes and presynaptic membrane, the latter with involvement of genes related to glutamatergic system (GRM3 and GRIK2), confirming its potential role in the response to IFNß.

Analysis of genes, pathways and networks involved in disease severity and age at onset in primary-progressive multiple sclerosis.

BACKGROUND: The role of genetic factors in influencing the clinical expression of multiple sclerosis (MS) is unclear. OBJECTIVE: The objective of this paper is to identify genes, pathways and networks implicated in age at onset (AAO) and severity, measured using the Multiple Sclerosis Severity Score (MSSS), of primary-progressive MS (PPMS). METHODS: We conducted a genome-wide association study (GWAS) of 470 PPMS patients of Italian origin:. Allelic association of 296,589 SNPs with AAO and MSSS was calculated. Pathway and network analyses were also conducted using different tools. RESULTS: No single association signal exceeded genome-wide significance in AAO and MSSS analyses. Nominally associated genes to AAO and MSSS were enriched in both traits for 10 pathways, including: "oxidative phosphorylation" (FDRAAO=9*10(-4); FDRMSSS=3.0*10(-2)), "citrate (TCA) cycle" (FDRAAO=1.6*10(-2); FDRMSSS=3.2*10(-3)), and "B cell receptor signaling" (FDRAAO=3.1*10(-2); FDRMSSS=2.2*10(-3)). In addition, an enrichment of "chemokine signaling pathway" (FDR=9*10(-4)) for AAO and of "leukocyte transendothelial migration" (FDR=2.4*10(-3)) for MSSS trait was observed, among others. Network analysis revealed that p53 and CREB1 were central hubs for AAO and MSSS traits, respectively. CONCLUSIONS: Despite the fact that no major effect signals emerged in the present GWAS, our data suggest that genetic variants acting in the context of oxidative stress and immune dysfunction could modulate the onset and severity of PPMS.