Brown adipose tissue can expend large amounts of energy and thus increasing its amount or activity is a promising therapeutic approach to combat metabolic disease. In humans, major deposits of brown fat cells are found intimately associated with large blood vessels, corresponding to perivascular adipose tissue (PVAT). However, the cellular origins of PVAT are poorly understood. We applied single cell transcriptomic analyses, ex vivo adipogenesis assays, and genetic fate mapping to determine the identity of perivascular adipocyte progenitors. In mice, we found that thoracic PVAT develops from a fibroblastic lineage, consisting of progenitor cells (Pdgfra+; Ly6a+; Pparg-) and preadipocytes (Pdgfra+; Ly6a+; Pparg+). Progenitor and preadipocyte cells in PVAT shared transcriptional similarity with analogous cell types in white adipose tissue, pointing towards a conserved hierarchical structure of adipose lineage cells. Interestingly, the aortic adventitia of adult animals contained a novel population of adipogenic smooth muscle cells (SMCs) (Myh11+; Pdgfra-; Pparg+) that contributed to perivascular adipocyte formation. Similarly, human PVAT contained presumptive fibroblastic and SMC-like adipocyte progenitors, as revealed by single nucleus RNAseq. Taken together, these studies define distinct populations of progenitor cells for thermogenic PVAT, providing a foundation for developing strategies to augment brown fat activity.
Overall design: Single Cell RNA Sequencing of cells from digested mosue aortas and associated perivascular adipose tissue at ages E18,P3, Adulthood (13 weeks) and single nucleus sequencing of human perivascular adipose tissue. For mice, individual analysis of each sample as well as integration of E18 and P3 datasets was performed. For humans samples, datasets were integrated and analyzed.
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