Introduction:
Inflammation plays a critical role in the pathogenesis of cardiovascular disease. Epigenetic mechanisms, including DNA methylation (DNAm), is critical in the regulation of inflammatory genes, and can be influenced by inflammation. The soluble form of cell adhesion molecules, including vascular adhesion molecule 1 (sVCAM1), intercellular adhesion molecule 1 (sICAM1), and P-selectin (sP-selectin), are established biomarkers for inflammation and endothelial function, and are linked to cardiovascular events.
Methods:
To identify epigenetic markers associated with inflammation and endothelial function, we conducted a methylome-wide association study and investigated over 480,000 DNAm sites of peripheral blood cells from 140 monozygotic (MZ) middle-aged male twins from the Emory Twin Study.
Results:
Using two randomly selected subsets consisting of unrelated subjects, we identified and replicated 69 and 23 DNAm sites significantly associated with sVCAM1, and sICAM1 respectively, adjusted for multiple testing, but none for sP-selectin. All 23 sICAM1-associated DNAm sites were also associated with sVCAM1, including sites on gene ANKRD11 (P=1.51х10-21, 2.62х10-20), KDM2B (P=1.52х10-21, 9.13х10-17), CAPS (P=2.81х10-20, 3.17х10-18), and CUX1 (P=7.63х10-20, 2.84х10-19). They jointly explained 54% and 40% of variance in sVCAM1 and sICAM1 respectively. Two DNAm sites, located on UNC5D and TMEM125, were also significant comparing MZ twins who were phenotypically discordant for both sICAM1 (P=1.79х10-7, 2.78х10-6) and sVCAM1 (P=1.70х10-9, 1.71х10-7).
Conclusions:
These results suggest that sVCAM1 and sICAM1, but not sP-selectin, may share common pathophysiology in inflammation and endothelial function via an epigenetic mechanism in leukocytes. In addition, the epigenetic association with inflammation may be driven by unshared environmental exposures.