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. 2017 Nov;14(Suppl 5):S399–S405. doi: 10.1513/AnnalsATS.201702-136AW

Figure 1.

Figure 1.

Reverse cholesterol transport pathway. Reverse cholesterol transport is the pathway by which tissue macrophages avoid toxic cholesterol overload. Cellular uptake of cholesterol from low-density lipoprotein (LDL) particles or oxidized LDL (oxLDL) particles via the LDL receptor (LDLR) or scavenger receptors (SRs), respectively, inhibits sterol response element–binding protein 2 (SREBP2) and activates liver X receptors (LXRs). The LXRs promote compensatory cholesterol efflux by upregulating ATP-binding cassette transporters A1 and G1 (ABCA1 and ABCG1, respectively). ABCA1 and ABCG1 together increase mobilization of cellular cholesterol to high-density lipoprotein (HDL) particles in the extracellular space. Plasma HDL delivers cholesterol to hepatocytes, where it is internalized via scavenger receptor BI (SR-BI). Cholesterol cleared from the plasma is then exported to the biliary system and from there to the intestinal lumen, where it can be excreted from the host. Apo B100 = apolipoprotein B 100; ApoA-1 = apolipoprotein A-I.