Epigenetic Patterns in Blood Associated With Lipid Traits Predict Incident Coronary Heart Disease Events and Are Enriched for Results From Genome-Wide Association Studies

Circ Cardiovasc Genet. 2017 Jan;10(1):e001487. doi: 10.1161/CIRCGENETICS.116.001487.

Abstract

Background: Genome-wide association studies have identified loci influencing circulating lipid concentrations in humans; further information on novel contributing genes, pathways, and biology may be gained through studies of epigenetic modifications.

Methods and results: To identify epigenetic changes associated with lipid concentrations, we assayed genome-wide DNA methylation at cytosine-guanine dinucleotides (CpGs) in whole blood from 2306 individuals from 2 population-based cohorts, with replication of findings in 2025 additional individuals. We identified 193 CpGs associated with lipid levels in the discovery stage (P<1.08E-07) and replicated 33 (at Bonferroni-corrected P<0.05), including 25 novel CpGs not previously associated with lipids. Genes at lipid-associated CpGs were enriched in lipid and amino acid metabolism processes. A differentially methylated locus associated with triglycerides and high-density lipoprotein cholesterol (HDL-C; cg27243685; P=8.1E-26 and 9.3E-19) was associated with cis-expression of a reverse cholesterol transporter (ABCG1; P=7.2E-28) and incident cardiovascular disease events (hazard ratio per SD increment, 1.38; 95% confidence interval, 1.15-1.66; P=0.0007). We found significant cis-methylation quantitative trait loci at 64% of the 193 CpGs with an enrichment of signals from genome-wide association studies of lipid levels (PTC=0.004, PHDL-C=0.008 and Ptriglycerides=0.00003) and coronary heart disease (P=0.0007). For example, genome-wide significant variants associated with low-density lipoprotein cholesterol and coronary heart disease at APOB were cis-methylation quantitative trait loci for a low-density lipoprotein cholesterol-related differentially methylated locus.

Conclusions: We report novel associations of DNA methylation with lipid levels, describe epigenetic mechanisms related to previous genome-wide association studies discoveries, and provide evidence implicating epigenetic regulation of reverse cholesterol transport in blood in relation to occurrence of cardiovascular disease events.

Keywords: DNA Methylation; cardiovascular diseases; epigenomics; gene expression; lipids.

MeSH terms

  • Aged
  • Biomarkers / blood
  • Coronary Disease / blood
  • Coronary Disease / diagnosis
  • Coronary Disease / epidemiology
  • Coronary Disease / genetics*
  • CpG Islands
  • Cross-Sectional Studies
  • DNA Methylation*
  • Dyslipidemias / blood
  • Dyslipidemias / diagnosis
  • Dyslipidemias / epidemiology
  • Dyslipidemias / genetics*
  • Epigenesis, Genetic*
  • Epigenomics / methods
  • Europe / epidemiology
  • Female
  • Genetic Predisposition to Disease
  • Genome-Wide Association Study
  • Humans
  • Incidence
  • Lipid Metabolism / genetics*
  • Lipids / blood*
  • Male
  • Metabolomics / methods
  • Middle Aged
  • Phenotype
  • Prognosis
  • Prospective Studies
  • Quantitative Trait Loci*
  • Risk Assessment
  • Risk Factors
  • United States / epidemiology

Substances

  • Biomarkers
  • Lipids