TFEB-mediated activation of the lysosome-autophagy system affects the transduction efficiency of adeno-associated virus 2.

Adeno-associated virus (AAV)-mediated gene transfer is an appealing therapeutic option due to AAV's safety profile. Effective delivery of AAV's genetic cargo to the nucleus, however, requires evasion of host cell barriers, including cellular clearance mechanisms mediated by the lysosome-autophagy system. We used AAV serotype 2 to monitor the autophagic response to cellular internalization of AAV and to characterize the effect of AAV-induced activation of autophagy on transgene expression. We found AAV2 internalization to induce activation of transcription factor EB, a master regulator of autophagy and lysosomal biogenesis, and upregulation of the lysosome-autophagy system. We showed that AAV2-induced activation of autophagy parallels a reduction in transgene expression, but also an increase in autophagic clearance of protein aggregates. These results can inform the design of AAV vectors with autophagy-modulating properties for applications ranging from the design of efficient gene delivery vectors to the treatment of diseases characterized by accumulation of autophagic cargo.