ABCA1 and atherosclerosis: As TGF-β downregulates scavenger receptors, such as scavenger receptor type A (SR-A) I/II and CD36 [25], and upregulates ATP-binding cassette (ABC) transporters, ABCA1 and ABCG1 [26], TGF-β is also thought to have protective effects against the development of atherosclerosis.