AAV vector-mediated in vivo miRNA antagonism for studying miRNA function and treating dyslipidemia

Understanding the function of individual miRNA species in mice would require the production of hundreds of loss-of-function strains. To accelerate analysis of miRNA biology in mammals, we combined recombinant adeno-associated virus (rAAV) vectors with miRNA ‘Tough Decoys’ (TuDs) to inhibit specific miRNAs. Intravenous injection of rAAV9 expressing anti-miR-122 or anti-let-7 TuD depleted the corresponding miRNA and increased its mRNA targets. rAAV producing anti-miR-122—but not anti-let-7—TuD reduced serum cholesterol by 40% for 18 weeks in wild-type mice and reduced serum LDL by 50% in LDL receptor-deficient mice. High throughput sequencing of liver miRNAs from the treated mice confirmed that the targeted miRNA, but no other miRNAs, were depleted and revealed that TuD RNAs induce miRNA tailing and trimming in vivo. rAAV-mediated miRNA inhibition thus provides a simple way to study miRNA function in adult mammals and a potential therapy for dyslipidemia and other diseases caused by miRNA deregulation. Overall design: Examining the effect of Tough Decoy miRNA inhibitors on miRNA stability and integrity

3

Xie J, Ameres SL, Friedline R, Hung JH, Zhang Y, Xie Q, Zhong L, Su Q, He R, Li M, Li H, Mu X, Zhang H, Broderick JA, Kim JK, Weng Z, Flotte TR, Zamore PD, Gao G