Endothelin-1 clearance by endothelin-B receptor–expressing LYVE1+ macrophages limits cardiometabolic disease progression

Background Endothelin-1 (ET-1) is a potent vasoactive and pro-inflammatory peptide implicated in obesity and atherosclerotic cardiovascular disease. While endothelin receptor B (ETB) is known to mediate ET-1 clearance, the immune cell populations that control systemic and tissue ET-1 levels are not fully delineated. We hypothesised that LYVE1⁺ resident macrophages expressing ETB constitute a conserved ET-1 clearance axis whose dysfunction promotes cardiometabolic disease, including obesity and atherosclerosis. Methods and Results Using murine single-cell and bulk RNA-sequencing, flow cytometry and immunofluorescence in mouse and human tissues, we identified LYVE1⁺ resident macrophages in aorta, adipose tissue, skin and heart epicardium as the myeloid subset with the highest Ednrb/ETB expression. In vitro, sorted epididymal LYVE1⁺ macrophages, but not LYVE1⁻ cells, efficiently removed ET-1 from culture media in an ETB-dependent manner; this clearance was blunted by the ETB antagonist BQ788. In vivo, pharmacological depletion of resident macrophages and genetic deletion of Ednrb in LYVE1⁺cells (Lyve1ΔEdnrb mice) both increased plasma ET-1 without altering monocyte counts or ET-1 synthesis in lung, adipose tissue and aorta, suggesting an ETB-mediated clearance defect. In a high-fat diet–induced obesity model, Lyve1ΔEdnrb mice showed greater weight gain (Fig. 1), increased visceral and brown adipose mass, higher adipose and hepatic ET-1 levels, more crown-like structures and adipocyte hypertrophy, and aggravated steatohepatitis, despite similar glycaemia and plasma cholesterol compared with floxed littermate controls. Notably, obese Lyve1ΔEdnrb mice exhibited vascular remodelling characterised by reduced aortic medial smooth muscle α-actin density and decreased adventitial collagen I deposition, without changes in luminal diameter. In a complementary PCSK9-driven atherosclerosis model, Lyve1ΔEdnrb mice displayed elevated aortic ET-1 accumulation as well as exacerbated lesion size and necrotic core independently of cholesterol levels or monocyte counts. Substantiating the proatherogenic potential of ET-1, dual ETA/ETB receptor blockade with bosentan reduced lesion burden. Conclusions ETB-expressing LYVE1⁺ resident macrophages constitute a major cellular effector of systemic ET-1 clearance whose disruption leads to ET-1 accumulation, adipose inflammation, exacerbated diet-induced obesity and aggravatedatherosclerosis, thereby identifying the LYVE1–ETB macrophage axis as a potential therapeutic target in cardiometabolic disease. Fig. 1: A). Schematic diagram for diet-induced obesity model. Lyve-1cre/wtEdnrBflox/flox (Lyve1ΔEdnrb) and EdnrBflox/floxmale mice were placed on high-fat diet (HFD) for 18 weeks. (B). Weight difference of mice over the course of 18 weeks, p<0,05.