Project description:We performed microarray analyses comparing perivascular adipose tissue gene expression of thoracic aortic vs. left internal mammary artery in human subjects with coronary artery disease. 300 genes were significantly upregulated in aortic fat, with at least 63 genes involved in inflammation and atherosclerosis. qPCR validation demonstrated increased expression of WNT-5A related genes, and CCL-2, CCL-8, JNK, and IL-6 gene expression.
Project description:Although inflammation plays critical roles in the development of atherosclerosis, its regulatory mechanisms remain incompletely understood. Perivascular adipose tissue (PVAT) has been reported to undergo inflammatory changes in response to vascular injury. Here, we showed that vascular injury induced the beiging (brown adipose tissue-like phenotype change) of PVAT, which fine-tunes inflammatory response and thus vascular remodeling as a protective mechanism. In a mouse model of endovascular injury, macrophages accumulated in PVAT, causing beiging phenotype change. Inhibition of PVAT beiging by genetically silencing PRDM16, a key regulator to beiging, exacerbated inflammation and vascular remodeling following injury. Conversely, activation of PVAT beiging attenuated inflammation and pathological vascular remodeling. Single-cell RNA sequencing revealed that beige adipocytes abundantly expressed neuregulin 4 (Nrg4) which critically regulated alternative macrophage activation. Importantly, significant beiging was observed in the diseased aortic PVAT in patients with acute aortic dissection. Taken together, vascular injury induced the beiging of adjacent PVAT with macrophage accumulation, where NRG4 secreted from the beige PVAT facilitated alternative activation of macrophages, leading to the resolution of vascular inflammation. Our study demonstrated the pivotal roles of PVAT in vascular inflammation and remodeling and will open a new avenue for treating atherosclerosis.
Project description:Chronic low-grade visceral white adipose tissue (WAT) inflammation is a hallmark of metabolic syndrome in obesity. Here, we demonstrate that a subpopulation of adipose tissue perivascular (PDGFRb+) cells, termed “fibro-inflammatory progenitors” (FIPs), activate pro-inflammatory signaling cascades shortly after the onset of high-fat diet feeding of mice and regulate pro-inflammatory macrophage accumulation in WAT in a TLR4-dependent manner. FIPs activation in obesity is mediated by the downregulation of ZFP423, identified here as a transcriptional co-regulator of NFkB. Biochemical analysis of ZFP423-protein complexes and ChIP-seq analysis reveal that ZFP423 suppresses the DNA-binding capacity of the p65 subunit of NFkB by inducing a p300 to NuRD co-regulator switch. Doxycycline-inducible expression of Zfp423 in PDGFRb+ cells suppresses inflammatory signaling in FIPs and attenuates metabolic inflammation of visceral WAT in obesity. Inducible inactivation of Zfp423 in PDGFRb+ cells increases FIP activity, exacerbates adipose macrophage accrual, and promotes WAT dysfunction. These studies implicate perivascular mesenchymal cells as important regulators of chronic adipose tissue inflammation in obesity and identify ZFP423 as a transcriptional break on NFkB signaling.
Project description:Thoracic perivascular adipose tissue (PVAT) is a unique adipose depot that likely influences vascular function and susceptibility to pathogenesis in obesity and metabolic syndrome. Surprisingly, PVAT has been reported to share characteristics of both brown and white adipose, but a detailed direct comparison to interscapular brown adipose tissue (BAT) has not been performed. Here we show by full genome DNA microarray analysis that global gene expression profiles of PVAT are virtually identical to BAT, with equally high expression of Ucp-1, Cidea and other genes known to be uniquely or very highly expressed in BAT. PVAT and BAT also displayed nearly identical phenotypes upon immunohistochemical analysis, and electron microscopy confirmed that PVAT contained multilocular lipid droplets and abundant mitochondria. Compared to white adipose tissue (WAT), PVAT and BAT from C57BL/6 mice fed a high fat diet for 13 weeks had markedly lower expression of immune cell-enriched mRNAs, suggesting resistance to obesity-induced inflammation. Indeed, staining of BAT and PVAT for macrophage markers (F4/80, CD68) in obese mice showed virtually no macrophage infiltration, and FACS analysis of BAT confirmed the presence of very few CD11b+/CD11c+ macrophages in BAT (1.0%) in comparison to WAT (31%). In summary, murine PVAT from the thoracic aorta is virtually identical to interscapular BAT, is resistant to diet-induced macrophage infiltration, and thus may play an important role in protecting the vascular bed from thermal and inflammatory stress. 8-week-old male C57BL6/J mice were fed a normal (ND) or high fat diet (HFD) (Research Diets 12451, 45 kcal% fat) for 13 weeks. Mice were then euthanized and four different adipose depots were harvested for RNA analysis: perivascular fat from the lesser curvature of the aortic arch (PVAT), interscapular brown adipose (BAT), inguinal adipose tissue (SAT), and epididymal adipose tissue (VAT). 250 ng total RNA pooled from two mice was used for cDNA synthesis; 3 biological replicates per tissue and diet were performed for a total of 24 hybridizations.
Project description:Previous publications demonstrated that there were anatomical, physiological, cellular, clinical and prognostic differences among adipose tissue present in subcutaneous areas, abdominal cavity and outside adventitial layer of artery. Thus, we wondered whether ASCs from subcutaneous adipose tissue, abdominal adipose tissue and perivascular adipose tissue were also different in gene expression. Here we performed bulk RNA-Seq assay for subcutaneous, abdominal and perivascular adipose derived stem cells.
Project description:Perivascular adipose tissue (PVAT) is vital for vascular homeostasis and PVAT dysfunction is associated with increased atherosclerotic plaque burden.
Project description: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.
Project description: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
Project description: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