Annexin 2-caveolin 1 complex is a target of ezetimibe and regulates intestinal cholesterol transport

Modulation of cholesterol absorption in the intestine, the primary site of dietary cholesterol uptake in humans, can have profound clinical implications. We have undertaken a reverse genetic approach by disrupting putative cholesterol processing genes in zebrafish larvae by using morpholino (MO) antisense oligonucleotides. By using targeted MO injections and immunoprecipitation (IP) experiments coupled with mass spectrometry, we determined that annexin (ANX)2 complexes with caveolin (CAV)1 in the zebrafish and mouse intestine. The complex is heat stable and unaffected by SDS or reducing conditions. MO targeting of anx2b or cav1, which are both strongly expressed in the larval and adult zebrafish intestinal epithelium, prevents formation of the protein heterocomplex. Furthermore, anx2b MO injection prevents processing of a fluorescent cholesterol reporter and results in reduced sterol mass. Pharmacological treatment of mice with ezetimibe disrupts the heterocomplex in only hypercholesterolemic animals. These data suggest that ANX2 and CAV1 are components of an intestinal sterol transport complex.