Estrogen prevents atherosclerosis by promoting macrophage cholesterol crystal metabolism via estrogen receptor alpha (ERα)

Abstract The accumulation of macrophages and cholesterol crystals in atherosclerotic plaques is an important pathological feature of patients with the acute coronary syndrome (ACS). Decreased estrogen levels and estrogen receptors (ERs) lead to an increase in atherosclerosis in postmenopausal women. Whether estrogen prevents atherosclerosis by promoting macrophage cholesterol crystal metabolism via estrogen receptor alpha (ERα) is unknown. The ascending aorta of postmenopausal women decreased the fibrous cap around the plaque, increased the aggregation of CC and macrophages, and reduced the expression of ERα, and transcription factor EB (TFEB). Estrogen supplementation ameliorated atherosclerosis, and reduced CC and macrophages in the cardiac aorta and CC in primary peritoneal macrophages in OVX LDLR−/− mice. Silencing TFEB eliminated the effect of estrogen in enhancing lysosomal function, promoting CC internalization in lysosomes, and promoting reverse cholesterol transport (RCT) through APOA1, but did not affect triglyceride (TG) accumulation or RCT mediated by HDL in macrophages. Inhibition of hormone-sensitive lipase (HSL) decreased the effect of estrogen in increasing RCT through APOA1 and HDL and decreasing TG in macrophages. Inhibition of ERα weakened the effect of estrogen in reducing CC, TG, total cholesterol(TC), free cholesterol(FC), and cholesterol ester (CE) in macrophages. Silencing ERα eliminated the effect of estrogen in increasing lysosomal function and promoting the expression of TFEB, HSL, ABCA1/ABCG1 and inhibiting the expression of NLRP3 and IL-1β in macrophages. Our results provide evidence that estrogen promotes macrophage CC metabolism, which includes increasing the internalization of CC in lysosomes through rescuing the lysosomal biogenesis program by the ERα-TFEB pathway and promoting RCT via ERα-TFEB and HSL pathways to increase the cholesterol efflux.