Ezetimibe impairs transcellular lipid trafficking and induces large lipid droplet formation in intestinal absorptive epithelial cells

• Published in: Biochimica et biophysica acta. Molecular and cell biology of lipids Vol. 1865; no. 12; p. 158808
• Main Authors: Nakano, Takanari, Inoue, Ikuo, Takenaka, Yasuhiro, Ito, Rina, Kotani, Norihiro, Sato, Sawako, Nakano, Yuka, Hirasaki, Masataka, Shimada, Akira, Murakoshi, Takayuki
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2020
• Subjects: Animals; Anticholesteremic Agents - pharmacology; Biological Transport - drug effects; Caco-2 Cells; Cholesterol; Chylomicron; Enterocytes; Epithelial Cells - drug effects; Epithelial Cells - metabolism; Ezetimibe; Ezetimibe - pharmacology; Humans; Intestinal Absorption - drug effects; Intestinal Mucosa - drug effects; Intestinal Mucosa - metabolism; Lipid droplet; Lipid Droplets - drug effects; Lipid Droplets - metabolism; Lipid Metabolism - drug effects; Mice, Inbred C57BL; Niemann-Pick C1-like 1; Enterocytes; Chylomicron; Lipid droplet; Cholesterol; Ezetimibe; Niemann-Pick C1-like 1
• ISSN: 1388-1981; 1879-2618
• DOI: 10.1016/j.bbalip.2020.158808

Ezetimibe inhibits Niemann-Pick C1-like 1 (NPC1L1) protein, which mediates intracellular cholesterol trafficking from the brush border membrane to the endoplasmic reticulum, where chylomicron assembly takes place in enterocytes or in the intestinal absorptive epithelial cells. Cholesterol is a minor lipid constituent of chylomicrons; however, whether or not a shortage of cholesterol attenuates chylomicron assembly is unknown. The aim of this study was to examine the effect of ezetimibe, a potent NPC1L1 inhibitor, on trans-epithelial lipid transport, and chylomicron assembly and secretion in enterocytes. Caco-2 cells, an absorptive epithelial model, grown onto culture inserts were given lipid micelles from the apical side, and chylomicron-like triacylglycerol-rich lipoprotein secreted basolaterally were analyzed after a 24-h incubation period in the presence of ezetimibe up to 50 μM. The secretion of lipoprotein and apolipoprotein B48 were reduced by adding ezetimibe (30% and 34%, respectively). Although ezetimibe allowed the cells to take up cholesterol normally, the esterification was abolished. Meanwhile, oleic acid esterification was unaffected. Moreover, ezetimibe activated sterol regulatory element-binding protein 2 by approximately 1.5-fold. These results suggest that ezetimibe limited cellular cholesterol mobilization required for lipoprotein assembly. In such conditions, large lipid droplet formation in Caco-2 cells and the enterocytes of mice were induced, implying that unprocessed triacylglycerol was sheltered in these compartments. Although ezetimibe did not reduce the post-prandial lipid surge appreciably in triolein-infused mice, the results of the present study indicated that pharmacological actions of ezetimibe may participate in a novel regulatory mechanism for the efficient chylomicron assembly and secretion. [Display omitted] •Enterocytes pack alimentary triglyceride as chylomicrons (CMs) with cholesterol.•Niemann-Pick C1-like 1 (NPC1L1) mediates cholesterol supply for CM assembly.•Ezetimibe, an NPC1L1 inhibitor, reduced CM secretion in Caco-2 cells.•Lipid droplets emerged in lipid-absorbing enterocytes in mice treated with ezetimibe.•NPC1L1 may be involved in efficient CM assembly and secretion.