Sativex® effects on promoter methylation and on CNR1/CNR2 expression in peripheral blood mononuclear cells of progressive multiple sclerosis patients.

Multiple sclerosis (MS) is a chronic demyelinating central nervous system (CNS) disease that involve oligodendrocyte loss and failure to remyelinate damaged brain areas causing a progressive neurological disability. Studies in MS mouse model suggest that cannabinoids ameliorate symptoms as spasticity, tremor and pain reducing inflammation via cannabinoid-mediated system. The aim of our study is to investigate the changes in cannabinoid type 1 (CNR1) and 2 (CNR2) receptors mRNA expression levels and promoter methylation in peripheral blood mononuclear cells (PBMCs) of MS secondary progressive (MSS-SP) patients treated with Sativex®. Our cohort included MSS-SP patients, that at the time of Sativex® treatment, are treated (n=7), not treated (n=11) or that had terminated interferon-β-1b (IFN-β-1b) therapy (n=12). By Methylation Sensitive High Resolution Melting (MS-HRM), we characterized the methylation profile of CNR1 and CNR2 promoter region, while the relative mRNA transcript levels of these two genes were evaluated in the same samples by Quantitative Real-Time PCR (qRT-PCR) analysis. We did not find different pattern of cytosine-phosphate-guanine (CpG) methylation in the CNR1/CNR2 promoter region of all MSS-SP patients treated with Sativex®. In addition, CNR1 and CNR2 expression did not significantly differ in MSS-SP patients not treated with IFN-β-1b vs. them that have suspended, while in MSS-SP patients treated with IFN-β-1b during Sativex® therapy we found a specific decrease of the CNR2 expression levels. These results suggest that the different expression of cannabinoid receptors by Sativex® treatment in leukocytes might be regulated through a molecular mechanism that involve interferon modulation.