Abstract 13073: Klf4 Dependent Plasticity of Perivascular Cells is Detrimental for Diet Induced Obesity Associated Adipose Tissue Inflammation and Fibrosis

Smooth muscle cells and pericytes (SMC-P) are not terminally differentiated and display remarkable plasticity in response to injury or atherosclerosis. Our lab previously demonstrated that the majority of SMC-P derived cells within advanced atherosclerotic lesions lack typical SMC markers such as Acta2 and activate markers of stem cells, myofibroblasts, and macrophages. Moreover, we showed that SMC knockout of the pluripotency gene Klf4 resulted in smaller lesions with increased plaque stability and a marked reduction in SMC-derived lesion cells that express macrophage or stem cell markers. Given that atherosclerosis develops well beyond our reproductive years, we hypothesized that Klf4-dependent phenotypic transitions of SMC-P also occur within the microvasculature of adipose tissue in healthy mice but play an evolutionarily conserved protective role. To test this, we performed scRNAseq analyses of stromovascular cells from epidydimal adipose tissue of Myh11-Cre ERT2 eYFP lineage tracing mice including samples enriched for eYFP+ (SMC-P derived; eYFP+ CD45+ CD11b+ F4/80+) or eYFP- (non-SMC-P derived; eYFP- CD45+ CD11b+ F4/80+) adipose tissue macrophages. FACS based analysis showed a large fraction of putative eYFP+ macrophages were within the macrophage island clusters; albeit with very low eYFP transcript reads, indicating that virtually all of these cells were eYFP- macrophages that exhibited auto fluorescence in the eYFP channel likely because of engorgement with peanut oil, the vehicle used for i.p. delivery of tamoxifen. To circumvent this limitation, we re-analyzed our scRNAseq dataset considering “only eYFP transcript positive cells” as being SMC-P derived. Results showed 27 distinct UMAP transcriptomic clusters of which six contained 88% of eYFP transcript+ cells representing SMC-P subsets. More than half of the remaining 12% eYFP+ cells were enriched in Sca1+ Lgals3+ clusters. SMC-P Klf4 knockout mice had reduced SMC-P derived Sca1+ cells, improved glucose tolerance, and fewer pro-inflammatory macrophages. Results indicate that the summation of Klf4 dependent changes in SMC-P plasticity, which we previously showed were detrimental in the pathogenesis of atherosclerosis, are also detrimental for overall metabolism.