Combining evidence from four immune cell types identifies DNA methylation patterns that implicate functionally...

Area of Science:

• Immunology
• Epigenetics
• Neuroscience

Background:

• Multiple Sclerosis (MS) is a chronic inflammatory neurological disease causing progressive disability.
• DNA methylation is a key epigenetic mechanism influenced by genes and environment, potentially revealing insights into MS.
• Understanding MS pathogenesis requires exploring molecular mechanisms like DNA methylation.

Purpose of the Study:

• To investigate DNA methylation differences across immune cell types in Multiple Sclerosis (MS) patients.
• To identify specific epigenetic markers associated with MS subtypes and disease progression.
• To leverage a novel statistical framework for enhanced discovery of methylation changes in MS.

Main Methods:

• DNA methylation was measured in CD4+ T cells, CD8+ T cells, CD14+ monocytes, and CD19+ B cells from MS patients and healthy controls using Infinium HumanMethylation450 arrays.
• Validation cohorts of monocytes and whole blood were utilized.
• A non-parametric combination framework (omicsNPC) was implemented to integrate data from multiple cell types.

Main Results:

• B cells showed the most significant differentially methylated positions (DMPs) in MS patients, followed by monocytes; T cells had fewer DMPs.
• The omicsNPC framework identified shared DMPs co-localizing at MS risk loci.
• Functional analysis revealed that MS-associated methylation changes implicate lymphocyte signaling, T cell activation/migration, myeloid cell functions, metabolism, and neurodegenerative pathways, particularly in SPMS.

Conclusions:

• The omicsNPC statistical framework effectively combines multi-cell type evidence to identify novel DNA methylation changes in MS.
• These findings provide new insights into the pathogenesis of MS and its progression.
• Epigenetic alterations in immune cells, especially B cells and monocytes, are crucial in understanding MS.