Global chromatin accessibility using an Assay for Transposase-Accessible Chromatin sequencing (ATAC-seq) reveals epigenomic reprogramming of Adipose tissue macrophages toward proinflammatory and proangiogenic phenotypes in formerly obese mice.

We report sustained changes in the chromatin accessibility landscape of adipose tissue macrophages (ATMs) from high fat diet (HFD)-fed mice persist long after return to regular diet (RD). We compared the data of ATAC-seq performed on nuclei extracted from FACS-sorted ATMs isolated from HFD, RD-RD and HFD-RD-fed mice. Inter-group comparisons revealed the highest diversity and hence the greatest number of differentially accessible regions (DARs) to occur between ATMs from RD-RD and HFD-RD-fed mice, and considerably fewer DARs were identified between ATMs from HFD-RD vs HFD-fed mice. Association of DARs with the nearest gene and gene ontology (GO) enrichment analysis revealed considerable pathway enrichment, especially pathways coding for angiogenesis and inflammatory response, in HFD-RD group when compared to RD-RD group. The results altogether indicated that most changes in chromatin landscape induced by HFD-feeding are maintained as open chromatin positions for a long time, suggesting that HFD-feeding leads to long-term reprograming of ATMs and renders them prone to pro-angiogenic and pro-inflammatory responses. Overall design: We performed ATAC-seq on nuclei extracted from FACS-sorted ATMs isolated from HFD, RD-RD and HFD-RD-fed mice.