Genomic, Epigenomic, and Immuno-Genomic Regulations of Vitamin D Supplementation in Multiple Sclerosis: A Literature Review and In Silico Meta-Analysis

Multiple sclerosis (MS) is a chronic autoimmune neurodegenerative disorder characterized by progressive demyelination and axonal degeneration within the central nervous system, driven by complex genomic and epigenomic dysregulation. Its pathogenesis involves aberrant DNA methylation patterns at CpG islands of numbers of genes like OLIG1 and OLIG2 disrupting protein expression at myelin with compromised oligodendrocyte differentiation. Furthermore, histone modifications, particularly H3K4me3 and H3K27ac, alter the promoter regions of genes responsible for myelination, affecting myelin synthesis. MS exhibits chromosomal instability and copy number variations in immune-regulatory gene loci, contributing to the elevated expression of genes for pro-inflammatory cytokines (TNF-α, IL-6) and reductions in anti-inflammatory molecules (IL-10, TGF-β1). Vitamin D deficiency correlates with compromised immune regulation through hypermethylation and reduced chromatin accessibility of vitamin D receptor (VDR) dysfunction and is reported to be associated with dopaminergic neuronal loss. Vitamin D supplementation demonstrates therapeutic potential through binding with VDR, which facilitates nuclear translocation and subsequent transcriptional activation of target genes via vitamin D response elements (VDREs), resulting in suppression of NF-κB signalling, enhancement of regulatory T-cell (T_reg) responses due to upregulation of specific genes like FOXP3, downregulation of pro-inflammatory pathways, and potential restoration of the chromatin accessibility of oligodendrocyte-specific gene promoters, which normalizes oligodendrocyte activity. Identification of differentially methylated regions (DMRs) and differentially expressed genes (DEGs) that are in proximity to VDR-mediated gene regulation supports vitamin D supplementation as a promising, economically viable, and sustainable therapeutic strategy for MS. This systematic review integrates clinical evidence and eventual bioinformatical meta-analyses that reference transcriptome and methylome profiling and identify prospective molecular targets that represent potential genetic and epigenetic biomarkers for personalized therapeutic intervention.