Morphological and functional changes in human monocyte-derived macrophages in response to in vitro reatment with ezetimibe, glucuronidated ezetimibe and S6130 (an ezetimibe derivate) and upon loading with atherogenic lipoproteins.

This study aimed to reveal morphological and functional changes in human monocyte-derived macrophages in response to in vitro reatment with ezetimibe, glucuronidated ezetimibe and S6130 (an ezetimibe derivate) and upon loading with atherogenic lipoproteins.
Conclusion:
Ezetimibe and S6130, but not glucuronidated ezetimibe disturbed the co-localization of CD13 and its co-receptor CD64 (Fc receptor I) in membrane microdomains, and decreased the presence of both receptors in detergent-resistant membrane fractions. Biotinylated cholesterol absorption inhibitor C-5 (i.e. derivative of ezetimibe) was rapidly internalized to perinuclear tubular structures of cells, resembling endoplasmic reticulum (ER), but CD13 was detected on extracellular sites of the plasma membrane and endo-lysosomal vesicles. Administration of ezetimibe, but not of glucuronidated ezetimibe or S6130, was associated with decreased cellular cholesteryl ester content, indicating the sterol-O acyltransferase 1 (SOAT1)-inhibition by ezetimibe. Furthermore, ezetimibe decreased the expression of molecules involved in cholesterol uptake and synthesis, in parallel with increased apolipoprotein A-I-mediated cholesterol efflux and up-regulation of efflux-effectors. However, NPC1L1 the other claimed molecular target of ezetimibe, was not detected in macrophages, thereby excluding this protein as target for ezetimibe in macrophages. Ezetimibe is very likely a CD13-linked microdomain-disruptor and SOAT1-inhibitor in macrophages leading to in vitro anti-atherosclerotic effects through a decrease of net cellular cholesterol content. Recording and subtraction of autofluorescence, Negative control: unstimulated cells treated with solvent of substances (DMSO)