Differential importance of endothelia and hematopoietic cell GLP-1Rs for cardiometabolic versus hepatic actions of semaglutide

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are used to treat diabetes and obesity and reduce rates of major cardiovascular events, such as stroke and myocardial infarction. Nevertheless, the identity of GLP-1R-expressing cell types mediating the cardiovascular benefits of GLP-1RA remains incompletely characterized. Herein, we investigated the importance of murine Glp1r expression within endothelial and hematopoietic cells. Mice with targeted inactivation of Glp1r in Tie2(+) cells exhibited reduced levels of Glp1r mRNA transcripts in aorta, liver, spleen, blood, and gut. Glp1r expression in bone marrow cells was very low and not further reduced in Glp1r(Tie2-/-) mice. The GLP-1RA semaglutide reduced the development of atherosclerosis induced by viral PCSK9 expression in both Glp1r(Tie2+/+) and Glp1r(Tie2-/-) mice. Hepatic Glp1r mRNA transcripts were reduced in Glp1r(Tie2-/-) mice, and liver Glp1r expression was localized to gamma delta T cells. Moreover, semaglutide reduced hepatic Tnf, Abcg1, Tgfb1, Cd3g, Ccl2, and Il2 expression; triglyceride content; and collagen accumulation in high-fat, high-cholesterol diet-fed Glp1r(Tie2+/+) mice but not Glp1r(Tie2-/-) mice. Collectively, these findings demonstrate that Tie2(+) endothelial or hematopoietic cell GLP-1Rs are dispensable for the antiatherogenic actions of GLP-1RA, whereas Tie2-targeted GLP-1R(+) cells are required for a subset of the antiinflammatory actions of semaglutide in the liver.