Angiotensin-(1-7) upregulates expression of adenosine triphosphate-binding cassette transporter A1 and adenosine triphosphate-binding cassette transporter G1 through the Mas receptor through the liver X receptor alpha signalling pathway in THP-1 macrophages treated with angiotensin-II.

Adenosine triphosphate-binding cassette transporter A1 (ABCA1) and ABCG1 play crucial roles in reverse cholesterol transport, and have anti-atherosclerosis effects, and liver X receptor alpha (LXRα) can stimulate cholesterol efflux through these transporters. Angiotensin (Ang)-(1-7) can protect endothelial cells, inhibit smooth muscle cell growth, ameliorate inflammation and exert anti-atherosclerotic effects. In the present study, we attempted to clarify the effect of Ang-(1-7) on expression of ABCA1 and ABCG1, and explored the role of LXRα in the regulation of ABCA1 and ABCG1 in THP-1 macrophages that had been incubated with angiotensin-II (AngII). Ang-(1-7) increased ABCA1 and ABCG1 expression in a concentration-dependent manner at both the mRNA and protein levels, promoted cholesterol efflux, and decreased cholesterol content in THP-1 macrophages treated with AngII. Furthermore, Ang-(1-7) upregulated the expression of LXRα in a concentration-dependent manner in these cells. LXRα small interfering RNA, as well as the Mas receptor antagonist A-779, completely abolished these effects of Ang-(1-7). In summary, Ang-(1-7) upregulates ABCA1 and ABCG1 expression in THP-1 macrophages treated with AngII through the Mas receptor, via the LXRα pathway. This novel insight into the molecular mechanism underlying Ang-(1-7) and AngII interaction could prove useful for developing new strategies for treatment of cardiovascular diseases.