Cholesterol absorption process in intestines

The **cholesterol absorption process in intestines** is a multistep biological pathway by which dietary and biliary cholesterol are taken up from the intestinal lumen into enterocytes—the absorptive cells lining the small intestine. This process involves several key steps and molecular players: *Cholesterol* is first solubilized in bile salt-containing micelles, which ferry it across the unstirred water layer to the brush border membrane of enterocytes. The main protein responsible for transporting free cholesterol from these micelles into enterocytes is **Niemann-Pick C1-Like 1** (**NPC1L1**), an integral membrane transporter located on the apical surface of these cells[3][6][1]. Once inside, *free cholesterol* must be transported to the endoplasmic reticulum, where it is esterified by **acyl-CoA:cholesterol acyltransferase 2** (**ACAT2**) for packaging into chylomicrons and subsequent release into lymphatic circulation[3]. Recent research has identified members of the *Aster protein family*—notably Aster-B and Aster-C—as critical facilitators that shuttle absorbed cholesterol from plasma membrane domains to intracellular compartments such as the endoplasmic reticulum[3]. This step bridges previously uncharacterized gaps between initial uptake via NPC1L1 and metabolic processing. Pharmacologically, this pathway can be targeted by drugs such as **ezetimibe**, which specifically inhibits NPC1L1 function at the brush border membrane, thereby reducing intestinal absorption of dietary and biliary cholesterol—a mechanism distinct from statins that target hepatic synthesis[6]. Because \"cholesterol absorption process in intestines\" refers to a complex physiological sequence rather than a discrete molecular entity or canonical therapeutic target (such as a receptor or enzyme), it does not fit standard definitions used for drug targets. Instead, individual proteins within this pathway—most notably NPC1L1—are considered bona fide therapeutic targets. In summary: > The \"cholesterol absorption process in intestines\" describes an essential physiological mechanism involving multiple proteins—including transporters like NPC1L1 and enzymes like ACAT2—that mediate dietary/biliary cholesterol entry into systemic circulation via intestinal epithelial cells. While not itself a single molecular target, components within this pathway are established drug targets for managing hypercholesterolemia and associated cardiovascular risks.[3][6][5]

Other names

Intestinal cholesterol absorptionEnterocyte cholesterol uptakeDietary cholesterol uptake in intestine

Inhibition of NPC1L1-mediated cholesterol uptake by enterocytes