Project description:Excessive accumulation of white adipose tissue (WAT) is a hallmark of obesity. The expansion of WAT in obesity involves proliferation and differentiation of adipose precursors (APs), however, the underlying molecular mechanisms remain unclear. Here, we identify Heme Oxygenase-1 (HO-1) as selectively being upregulated in the AP fraction of WAT, upon high-fat diet (HFD) feeding. Specific conditional deletion of HO-1 in APs of Hmox1fl/fl-Pdgfra Cre mice enhanced HFD-dependent visceral AP proliferation and differentiation, upstream of Cebpα and PPARγ. Opposite effects on human preadipocyte proliferation and differentiation in vitro were observed following HO-1 overexpression. Mechanistically, HO-1 acts upstream of AKT2 via ROS thresholding in mitochondria. Deletion of HO-1 in APs is sufficient to lower blood glucose, insulin and free fatty acid levels as well as liver steatosis during obesity, an effect not seen when HO-1 was conditionally deleted at later stages of adipogenesis using AdipoQ-Cre. Together, our data identify HO-1 as a diet-induced regulator limiting visceral adipose tissue hyperplasia during obesity.
Project description:Excessive accumulation of white adipose tissue (WAT) is a hallmark of obesity. The expansion of WAT in obesity involves proliferation and differentiation of adipose precursors (APs), however, the underlying molecular mechanisms remain unclear. Here, we identify Heme Oxygenase-1 (HO-1) as selectively being upregulated in the AP fraction of WAT, upon high-fat diet (HFD) feeding. Specific conditional deletion of HO-1 in APs of Hmox1fl/fl-Pdgfra Cre mice enhanced HFD-dependent visceral AP proliferation and differentiation, upstream of Cebpα and PPARγ. Opposite effects on human preadipocyte proliferation and differentiation in vitro were observed following HO-1 overexpression. Mechanistically, HO-1 acts upstream of AKT2 via ROS thresholding in mitochondria. Deletion of HO-1 in APs is sufficient to lower blood glucose, insulin and free fatty acid levels as well as liver steatosis during obesity, an effect not seen when HO-1 was conditionally deleted at later stages of adipogenesis using AdipoQ-Cre. Together, our data identify HO-1 as a diet-induced regulator limiting visceral adipose tissue hyperplasia during obesity.
Project description:As obesity progresses, dynamic tissue remodeling of adipose tissue occurs over time, i.e., adipocyte hypertrophy, chronic inflammation, and interstitial fibrosis. Some obese individuals exhibit healthy adipose tissue expansion, characterized by modest inflammation and fibrosis despite adipocyte hypertrophy, resulting in “Metabolically Healthy Obesity (MHO)”. Our research has revealed that MHO can be induced by temporary weight loss during the development of obesity.
Project description:As obesity progresses, dynamic tissue remodeling of adipose tissue occurs over time, i.e., adipocyte hypertrophy, chronic inflammation, and interstitial fibrosis. Some obese individuals exhibit healthy adipose tissue expansion, characterized by modest inflammation and fibrosis despite adipocyte hypertrophy, resulting in “Metabolically Healthy Obesity (MHO)”. Our research has revealed that MHO can be induced by temporary weight loss during the development of obesity.
Project description:Subcutaneous and visceral adipose depots employ distinct expansion strategies in response to dietary cues, yet the molecular regulators underlying these depot-specific adaptations remain poorly understood. Through integrated proteomic profiling of human subcutaneous and visceral adipose tissues from paired obese/non-obese donors and temporal transcriptomic analysis of mouse adipose stem and progenitor cells (ASPCs) during diet switching, we identified Gpc3 as an obesity-responsive gene exhibiting reciprocal expression patterns between depots. ASPC-specific Gpc3 deletion in mice amplified high-fat diet (HFD)-induced weight and fat mass gain by selectively enhancing hyperplastic expansion in inguinal white adipose tissue (iWAT), without affecting epididymal WAT (eWAT). Mechanistically, Gpc3 loss biased ASPC fate toward proliferation over adipogenesis via depot-specific modulation of canonical Wnt signaling. These findings establish Gpc3 as a regulator for regional adipose plasticity, offering a molecular target for reprogramming pathological fat distribution in obesity and related metabolic disorders.
Project description:Obesity is a major public health challenge affecting an ever-increasing proportion of the global population. It is associated with numerous comorbidities. Progressive expansion and remodeling of adipose tissue may lead to depot specific changes in adipose tissue biology and energy partitioning. Such changes likely precede the development of obesity-related complications. To facilitate a deeper understanding of adipose tissue biology, a comprehensive quantitative proteomic dataset is presented at the peptide and protein level. Data-independent acquisition LC-MS/MS data were acquired from matched subcutaneous and omental adipose tissues from metabolically healthy individuals with no comorbidities and covering a wide range of body mass indexes. Adipose tissue samples were collected during elective surgeries and immediately processed for histology or frozen until proteomic analysis. Internal and external quality control systems ensured high quality data. All data presented are available via ProteomeXchange. This dataset will allow new insights into biological changes that evolve with increasing adiposity captured before the onset of comorbidities. Matched sampling across fat depots provides an opportunity to uncover depot-specific physiological signatures.
Project description:A hallmark of obesity is a pathological expansion of white adipose tissue (WAT), accompanied by marked tissue dysfunction and fibrosis. Autophagy promotes adipocyte differentiation and lipid homeostasis, but its role in obese adipocytes and adipose tissue dysfunction remains incompletely understood. Using a mouse model, we demonstrate that autophagy is a key tissue-specific regulator of WAT remodelling in diet-induced obesity. Importantly, loss of adipocyte autophagy substantially exacerbates pericellular fibrosis in visceral WAT. Change in WAT architecture correlates with increased infiltration of macrophages with tissue-reparative, fibrotic features.
Project description:Visceral white adipose tissue is closed correlated with obesity and metabolic dysfunction. Epididymal adipose tissue (eWAT) is considered as typical visceral white adipose tissue. Induction of browning of white adipose tissue improves metabolic dysfunction such as insulin resistance. In contrast to mice subcutaneous adipose tissue, visceral fat do not show significant browning under 4°C. However,under physiologically tolerable low temperature visceral adipose tissue can turn brown. We used microarrays to detail the global programme of gene expression in C57Bl/6 mice epididymal adipose tissue exposed to thermoneutral 30°C, 4°C and temperatures lower than 4°C.