Increased DNA methylation variability in type 1 diabetes across three immune effector cell types

Area of Science:

• Immunology
• Epigenetics
• Genetics

Background:

• Type 1 diabetes (T1D) incidence is rising, indicating non-genetic factors like epigenetics may play a role.
• Epigenetic mechanisms, particularly DNA methylation, are increasingly recognized for their influence on complex diseases.

Purpose of the Study:

• To investigate epigenome-wide DNA methylation differences in monozygotic twin pairs discordant for T1D.
• To identify specific differentially variable CpG positions (DVPs) associated with T1D and their potential role in disease pathogenesis.

Main Methods:

• Conducted an epigenome-wide association study (EWAS) analyzing 406,365 CpGs in 52 monozygotic twin pairs discordant for T1D.
• Examined DNA methylation patterns in three immune effector cell types.
• Integrated findings with cell type-specific gene regulatory circuits and analyzed cord blood samples.

Main Results:

• Observed a significant enrichment of T1D-associated DVPs in affected twins compared to their healthy co-twins and unrelated individuals.
• Found these DVPs to be temporally stable and located at gene regulatory elements.
• Identified enrichment in pathways related to immune cell metabolism, cell cycle, and mTOR signaling, with evidence suggesting DVPs emerge postnatally.

Conclusions:

• Epigenetic alterations, specifically DNA methylation changes (DVPs), are implicated in the pathogenesis of type 1 diabetes.
• These changes likely arise after birth and are associated with key immune and metabolic pathways.
• The study provides insights into the role of epigenetics in T1D development, particularly in immune cells.