C-type lectin receptor CLEC4A2 promotes tissue adaptation of macrophages and protects against atherosclerosis.
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ABSTRACT:
SUBMITTER: Park I
PROVIDER: S-EPMC8752790 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The role of scavenger receptor class B, type I (SR-BI) in endothelial cells (EC) was examined in several novel transgenic mouse models expressing SR-BI in endothelium of mice with normal C57Bl6/N, apoE-KO, or Scarb1-KO backgrounds. Mice were also created expressing SR-BI exclusively in endothelium and liver. Endothelial expression of the Tie2-Scarb1 transgene had no significant effect on plasma lipoprotein levels in mice on a normal chow diet but on an atherogenic diet, significantly decreased plasma cholesterol levels, increased plasma HDL cholesterol (HDL-C) levels, and protected mice against atherosclerosis. In 8-month-old apoE-KO mice fed a normal chow diet, the Tie2-Scarb1 transgene decreased aortic lesions by 24%. Mice expressing SR-BI only in EC and liver had a 1.5 ± 0.1-fold increase in plasma cholesterol compared to mice synthesizing SR-BI only in liver. This elevation was due mostly to increased HDL-C. In EC culture studies, SR-BI was found to be present in both basolateral and apical membranes but greater cellular uptake of cholesterol from HDL was found in the basolateral compartment. In summary, enhanced expression of SR-BI in EC resulted in a less atherogenic lipoprotein profile and decreased atherosclerosis, suggesting a possible role for endothelial SR-BI in the flux of cholesterol across EC.
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Project description:Blood vessels are continually exposed to circulating lipids and elevations of ApoB containing lipoproteins cause atherosclerosis. Lipoprotein metabolism is highly regulated by lipolysis, largely at the level of the capillary endothelium lining metabolically active tissues. How large blood vessels, the site of atherosclerotic vascular disease, regulate the flux of fatty acids (FA) into triglyceride (TG) rich lipid droplets (LD) is not known. Here, we show that deletion of the enzyme, adipose triglyceride lipase (ATGL) in the endothelium, leads to neutral lipid accumulation in vessels and impairs endothelial dependent vascular tone and nitric oxide synthesis to promote endothelial dysfunction. Mechanistically, the loss of ATGL leads to endoplasmic reticulum stress-induced inflammation, thereby promoting EC dysfunction. Consistent with this mechanism, deletion of endothelial ATGL markedly increases lesion size in a model of atherosclerosis. Together, these data demonstrate that the dynamics of FA flux through LD impacts EC homeostasis and consequently large vessel function during normal physiology and in a chronic disease state
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