Niemann-Pick C1-like 1 (NPC1L1)

Niemann-Pick C1-like 1 (NPC1L1) is a multipass transmembrane protein primarily expressed on the apical surface of enterocytes in the small intestine and hepatocytes. It plays a critical role in mediating the uptake of dietary and biliary cholesterol into cells via vesicular endocytosis[4][5]. The structure includes an N-terminal domain that binds cholesterol, multiple luminal domains, a sterol-sensing domain embedded within its transmembrane region, and thirteen membrane-spanning helices[3][5].\n\nNPC1L1 is essential for intestinal cholesterol absorption; genetic or pharmacologic inhibition leads to significant reductions in plasma LDL-cholesterol. Ezetimibe is a selective inhibitor that targets this transporter to reduce blood cholesterol levels by about 15–20%[2][8][9]. Recent research has also identified Aster proteins as additional players downstream of NPC1L1 in the process of intracellular trafficking of absorbed sterols[6].\n\nBeyond cardiovascular disease risk reduction through lipid lowering, emerging data suggest possible roles for NPC1L1 in cancer biology due to its influence on cellular lipid metabolism[5]. There are no major safety concerns directly attributed to targeting this molecule with current therapies; initial concerns about increased cancer risk have not been substantiated by larger analyses[9].\n\nIn summary, Niemann-Pick C1-like 1 is an established therapeutic target central to intestinal sterol transport. Its inhibition forms the basis for non-statin oral therapies aimed at reducing cardiovascular risk through modulation of plasma lipids.

Other names

NPC1L1Niemann-Pick C1-Like 1 proteinNPC-1 like intracellular cholesterol transporter 1

Inhibition of cholesterol uptake at the intestinal brush border by blocking NPC1L1 function (e.g., ezetimibe binds to and inhibits NPC1L1, reducing dietary and biliary cholesterol absorption)[2][8][9]