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The mechanism of obesity‐related metabolic dysfunction involves the development of systemic inflammation, largely mediated by macrophages. Switching of M1‐like adipose tissue macrophages (ATMs) to M2‐like ATMs, a population of macrophages associated with weight loss and insulin sensitivity, is considered a viable therapeutic strategy for obesity‐related metabolic syndrome. However, mechanisms for reestablishing the polarization of ATMs remain elusive. This study demonstrates that CD146+ ATMs accumulate in adipose tissue during diet‐induced obesity and are associated with increased body weight, systemic inflammation, and obesity‐induced insulin resistance. Inactivating the macrophage CD146 gene or antibody targeting of CD146 alleviates obesity‐related chronic inflammation and metabolic dysfunction. Macrophage CD146 interacts with Glycoprotein 130 (Gp130), the common subunit of the receptor signaling complex for the interleukin‐6 family of cytokines. CD146/Gp130 interaction promotes pro‐inflammatory polarization of ATMs by activating JNK signaling and inhibiting the activation of STAT3, a transcription factor for M2‐like polarization. Disruption of their interaction by anti‐CD146 antibody or interleukin‐6 steers ATMs toward anti‐inflammatory polarization, thus attenuating obesity‐induced chronic inflammation and metabolic dysfunction in mice. The results suggest that macrophage CD146 is an important determinant of pro‐inflammatory polarization and plays a pivotal role in obesity‐induced metabolic dysfunction. CD146 could constitute a novel therapeutic target for obesity complications. [ABSTRACT FROM AUTHOR]

Obesity and its related complications pose an increasing threat to human health; however, targetable obesity‐related membrane receptors are not yet elucidated. Here, the membrane receptor CD146 is demonstrated to play an essential role in obesity. In particular, CD146 acts as a new adipose receptor for angiopoietin‐like protein 2 (ANGPTL2), which is thought to act on endothelial cells to activate adipose inflammation. ANGPTL2 binds to CD146 to activate cAMP response element‐binding protein (CREB), which then upregulates CD146 during adipogenesis and adipose inflammation. CD146 is present in preadipocytes and mature adipocytes, where it is mediated by its ligands ANGPTL2 and galectin‐1. In preadipocytes, CD146 ablation suppresses adipogenesis, whereas the loss of CD146 in mature adipocytes suppresses lipid accumulation and enhances energy expenditure. Moreover, anti‐CD146 antibodies inhibit obesity by disrupting the interactions between CD146 and its ligands. Together, these findings demonstrate that ANGPTL2 directly affects adipocytes via CD146 to promote obesity, suggesting that CD146 can be a potential target for treating obesity. [ABSTRACT FROM AUTHOR]