Adeno-Associated Virus based Caveolin-1 Delivery via Different Routes for the Prevention of Cholesterol Gallstone Formation

Background: The hepatic caveolin1 (CAV1) was reduced in cholesterol gallstone disease (CGD). And mice with CAV1 deficiency were prone to develop CGD. However, it remains unknown whether the restored hepatic CAV1 expression would prevent the development of CGD. Methods C57BL/6 mice were injected with adeno-associated virus 2/8 (AAV2/8) vectors carrying CAV1 gene ( AAV2/8 CAV1) via intravenous (i.v.) or intraperitoneal (i.p.) route and then were subjected to a lithogenic diet (LD) for 8 weeks. Uninjected mice were used as control. The functional consequences of rescuing CAV1 expression by either i.v. or i.p. AAV2/8 CAV1 treatment on CGD prevention and its subsequent molecular mechanisms were examined. Results The CAV1 expression was reduced in liver and gallbladder of LD-fed-induced CGD mice. We discovered that AAV2/8 CAV1 i.p. delivery results in higher transduction efficiency in the gallbladder than tail vein administration. And although either i.v. or i.p. injection of AAV2/8 CAV1 improved the liver lipid metabolic abnormalities in CGD mice, they did not affect LD feeding-induced bile cholesterol supersaturation. In comparison with i.v. administration route, i.p. administration of AAV2/8 CAV1 obviously increased CAV1 protein levels in the gallbladder of LD-fed mice. And i.p. delivery of AAV2/8 CAV1 would partially improve gallbladder cholecystokinin receptor (CCKAR) responsiveness and impede bile cholesterol nucleation, via the activation of adenosine monophosphate-activated protein kinase (AMPK) signaling induced a reduction of gallbladder mucin-1 (MUC1) and MUC5ac expression and gallbladder cholesterol accumulation. Conclusions CGD prevention by i.p. AAV2/8 CAV1 injection in LD-fed mice was associated with the improvement of gallbladder stasis, which again supported the notion that supersaturated bile is required but not sufficient for the formation of cholesterol gallstones. Additionally, AAV treatment via local i.p. injection offers particular advantages over the systemic i.v. route for much more effective gallbladder gene delivery, which will be an excellent tool for conducting preclinical functional studies on the maintenance of normal gallbladder function to prevent CGD.