Anti-Atherogenic Effect of Berberine on LXRα-ABCA1-Dependent Cholesterol Efflux in Macrophages

Berberine, a botanical alkaloid purified from Cortidis rhizonta. has effects in cardiovascular diseases, yet the mechanism is not fully understood Foam cells play a critical role in the progression of atherosclerosis. This study aimed to investigate the effect of berberine on the formation of foam cells by macrophages and the underlying mechanism Treatment with berberine markedly suppressed oxidized low-density lipoprotein (oxLDL)-mediated lipid accumulation, which was due to an increase in cholesterol efflux. Berberine enhanced the niRNA and protein expression of. ATP-binding membrane cassette transport protein At (ABCA 1) but did not alter the protein level of ABCG 1 or other scavenger receptors Additionally, functional Inhibition of ABCA 1 with a pharmacological inhibitor or neutralizing antibody abrogated the effects of berberine on cholesterol efflux and lipid accumulation. Moreover, berberine induced the nuclear translocation and activation of liver X receptor is (LXR alpha) but not its protein expression. Knockdown of LXR alpha mRNA expression by small interfering RNA abolished the berbenne-mediated protective effects on ABCA 1 protein expression and oxLDL-induced lipid accumulation in macrophages These data suggest that berberine abrogates the formation of foam cells by macrophages by enhancing LXR alpha-ABCA1-dependent cholesterol efflux J Cell Biochem. 111: 104-110. 2010. (C) 2010 Wilcy-liss, Inc