Adipose extracellular matrix deposition is an indicator of obesity and metabolic disorders

Obesity and metabolic disorders are threats to human health. Extracellular matrix (ECM) is an important member of adipose microenvironment. ECM remodeling contributes to obesity and insulin resistance, but the roles of every single ECM component is still not fully understood. We observed glucose and lipids metabolic disorders in high-fat diet (HFD)-fed mice and humans with obesity. Higher levels of inflammatory factors and hormones existed in serum of HFD-fed mice. Multiple collagens, laminins, fibronectin, nidogen, and Hspg2 were upregulated in obese white adipose tissue (WAT) from mice and humans. These effects were stronger in subcutaneous WAT than visceral WAT in mice, but the fat depot difference was reversed in humans. The ECM structure and the morphology of adipocytes seeded on ECM were changed in the HFD group. In human visceral WAT, ECM genes showed positive correlations with blood lipids and glucose. In vitro, collagen I/IV and LAMA4 proteins showed similar changes with C/EBPα during the differentiation of adipocytes. Macromolecular crowders (MMC) promoted partial collagen and non-collagen gene expression. Oleic acid (OA) and MMC upregulated collagen I/IV and LAMA4 proteins, and the effects of MMC were stronger than that of OA. Moreover, MMC promoted the differentiation of adipocytes, but OA increased the size of lipid droplets. Positive correlations were observed between ECM genes and adipogenesis-related genes in adipocytes. In conclusion, some obesogens (such as HFD) induce ECM remodeling, and the upregulation of ECM components is closely related to adipogenesis, suggesting that adipose ECM deposition is an indicator of obesity and metabolic disorders.