The drug-elicitable alternative splicing module for tunable vector expression in the heart.

Adeno-associated viruses (AAVs) are commonly used for gene therapy, but a clinically relevant method to fine-tune AAV expression is lacking, restricting their therapeutic efficacy and safety. Here we develop the drug-elicitable alternative splicing module (DreAM), which is responsive to risdiplam, a Food and Drug Administration-approved alternative splicing modulator. Risdiplam activated DreAM-regulated AAV expression in a dose-dependent manner with a 2,000-fold inducible change, depending on the dose of risdiplam and the organ of interest. With a temporal resolution of 2 days, DreAM could transiently, reversibly and repeatedly activate AAV expression according to the frequency and duration of risdiplam administration. In this proof-of-concept study, we incorporated DreAM into the cardiomyocyte-specific, liver-detargeted AAV9-Tnnt2-miR122TS vector to transiently activate the cardiomyocyte regeneration factor YAP^5SA. A dedifferentiation-proliferation-redifferentiation cycle was established in adult cardiomyocytes, improving cardiac regeneration after myocardial infarction while limiting animal death, AAV9-Tnnt2 expression in the liver and hepatic tumorigenesis. Therefore, DreAM may enhance the efficacy, safety and scope of gene therapy.