Epigenetic differences at the HTR2A locus in progressive multiple sclerosis patients

Area of Science:

• Immunology
• Neuroscience
• Genetics

Background:

• The underlying pathology of progressive multiple sclerosis (MS) remains largely unknown.
• Previous research identified differentially methylated regions (DMRs) in HLA-DRB1 and RNF39 in relapsing-remitting MS (RRMS) CD4+ T cells.

Purpose of the Study:

• To investigate DNA methylation profiles in the CD4+ T cells of patients with progressive MS.
• To identify potential epigenetic biomarkers distinguishing progressive MS from other forms of the disease.

Main Methods:

• DNA methylation analysis was performed on CD4+ T cells from two independent case/control cohorts using Illumina 450K/EPIC arrays.
• Data analysis involved the Chip Analysis Methylation Pipeline (ChAMP), PLINK for SNP assessment, and R (Limma, Illuminaio) for expression analysis.
• Single nucleotide polymorphisms (SNPs) and gene expression were also assessed to correlate with methylation changes.

Main Results:

• Three DMRs at HTR2A, SLC17A9, and HDAC4 were consistently identified across both progressive MS cohorts.
• The DMR at HTR2A remained significant even after accounting for regional single nucleotide polymorphisms (SNPs).
• No significant changes in gene expression were detected in the identified DMRs, suggesting methylation is independent of expression in this context.

Conclusions:

• Differential methylation at HTR2A in CD4+ T cells is a distinct feature of progressive MS, independent of genetic variations.
• This HTR2A methylation pattern is not observed in relapsing-remitting MS, indicating its potential as a specific biomarker for progressive disease.
• Further research is warranted to elucidate the functional impact of HTR2A differential methylation in progressive MS pathogenesis.