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Fig. 7 Membrane cholesterol depletion and ezetimibe inhibit endocytosis and fatty acid metabolism in zebrafish larvae.
(A?H) Histological cross sections through the anterior intestine of 6 day post-fertilization zebrafish larvae following ingestion and processing of the styryl dye AM1-43. (A) Red fluorescent endocytic vesicles are evident in enterocytes of a wild type larva soaked in AM1-43 for 4 hours. (B?D) Ezetimibe (50 μM) strongly inhibits AM1-43 uptake by enterocytes in a dose dependent manner. (E, F) A larva treated with methyl-β-cyclo-dextrin (MβC) shows little AM1-43 uptake 4 hours after MβC withdrawal (MβC t4) whereas AM1-43 uptake can be detected at 8 hours after MβC withdra25al (MβC t8). (G) Concomitant inhibition of cholesterol synthesis with atorvastatin (Atvn) prevents recovery of AM1-43 uptake following MβC withdrawal. (H) Atvn alone has no effect on AM1-43 uptake. (I) Metabolism of the LCFA BdpC16 (I) but not SCFA BdpC5 (J), as measured by gallbladder and intestinal fluorescence, is inhibited by membrane cholesterol depletion caused by MβC. (I) BdpC16 metabolism recovers following MβC withdrawal but not in the presence of Atvn. (J) By contrast, recovery of BdpC5 metabolism from the effects of MβC that are independent of cholesterol depletion occurs with or without Atvn treatment.