DNA Methylation Analysis in Classical Monocytes from African American Patients with Systemic Sclerosis

Systemic sclerosis is a multisystem autoimmune disorder that has an unclear etiology and disproportionately affects African Americans (AA). Additionally, monocytes show heightened activation in SSc, and in AA relative to European ancestry (EA) individuals. Monocytes are thus a good target tissue for elucidating disease mechanisms. In this study, we sought to investigate differentially methylated loci in classical monocytes from AA SSc patients and unaffected AA controls. We used Illumina’s MethylationEPIC BeadChip to profile DNA methylation patterns on FACS-isolated classical monocytes (CD14++CD16-) from 12 female AA SSc cases and 12 female AA controls. We observed modest DNA methylation differences between cases and controls. The genes harboring the top differentially methylated cytosines are enriched for immune pathways and metabolic processes. The relatively modest differences in DNA methylation observed between patients and controls is consistent with prior evidence of stronger inflammatory signatures in AA. Illumina’s MethylationEPIC BeadChip was used to profile DNA methylation on FACS-isolated classical monocytes (CD14++CD16-) from 12 female AA SSc cases and 12 female AA controls.