Novel epigenetic loci identified from an epigenome-wide association study underlying brain structural changes in...

Area of Science:

• Neuroscience
• Genetics
• Psychiatry

Background:

• DNA methylation is crucial for gene-environment interactions and brain development, particularly in bipolar disorder (BD).
• Understanding epigenetic modifications in BD is key to unraveling its complex etiology and neurobiological underpinnings.

Purpose of the Study:

• To identify DNA methylation loci associated with bipolar disorder.
• To investigate the relationship between identified epigenetic loci and brain structural variations, specifically cortical thickness.

Main Methods:

• Conducted an epigenome-wide association study comparing individuals with BD (n=90) and healthy controls (n=161).
• Performed copy number alteration and functional enrichment analyses.
• Assessed correlations between epigenetic loci and cortical thickness using Pearson's partial correlation analysis.

Main Results:

• Identified 156 differentially methylated positions (DMPs) and 7 differentially methylated regions, enriched in processes related to muscle hypertrophy and neuronal activity.
• Found significant correlations between methylation levels of 13 DMPs (involving genes miR886, PLEC1, ICAM5) and cortical thickness in specific brain regions.
• Observed negative correlations between miR886-associated CpG-island methylation and right postcentral gyrus cortical thickness, suggesting a link to cortical thinning.

Conclusions:

• Epigenetic alterations, particularly miR886-related methylation, may be molecular correlates of brain structural changes in bipolar disorder.
• These findings highlight the potential role of epigenetic modifications in the neurobiology of BD and suggest miR886 as a candidate marker.
• Further research with larger, diverse cohorts is warranted to validate these findings and explore underlying mechanisms.