Background: Previous studies showed that microRNA-29b (miR-29b) inhibits renal fibrosis. Therefore, miR-29b replacement therapy represents a promising approach for treating renal fibrosis. However, an efficient method of kidney-targeted miRNA delivery has yet to be established. Recombinant adeno-associated virus (rAAV) vectors have great potential for clinical application. For kidney-targeted gene delivery, the most suitable AAV serotype has yet to be established. Here, we identified the most suitable AAV serotype for kidney-targeted gene delivery and determined that AAV-mediated miR-29b delivery can suppress renal fibrosis in vivo.
Method: To determine which AAV serotype is suitable for kidney cells, GFP-positive cells were identified by flow cytometry after the infection of rAAV serotype 1-9 vectors containing the EGFP gene. Next, we injected rAAV vectors into the renal pelvis to determine transduction efficiency in vivo. GFP expression was measured seven days after injecting rAAV serotype 1-9 vectors carrying the EGFP gene. Finally, we investigated whether rAAV6-mediated miR-29b delivery can suppress renal fibrosis in UUO mouse model.
Results: We found that rAAV6 vector is the most suitable for targeting kidney cells regardless of animal species in vitro and rAAV6 is the most suitable vector for kidney-targeted in vivo gene delivery in mice. Intra-renal pelvic injection of rAAV vectors can transduce genes into kidney TECs. Furthermore, rAAV6-mediated miR-29b delivery attenuated renal fibrosis in UUO model by suppressing Snail1 expression.
Conclusion: Our study has revealed that rAAV6 is the most suitable serotype for kidney-targeted gene delivery and rAAV6-mediated miR-29b delivery into kidney TECs can suppress established renal fibrosis.
Keywords: AAV; Renal fibrosis; miR-29b; miRNA.