Myocardial infarction creates a critical time window for AAV gene therapy

Abstract Recombinant adeno-associated virus (AAV) is a major gene delivery vector for cardiac gene therapy. The factors that influence AAV-based cardiac gene transfer remain incompletely understood. This study showed that myocardial infarction (MI) enhanced cardiac AAV transduction and gene expression in mice after systemic administration, peaking at the third day post MI. These additional AAV vectors enriched at the infarcted region, correlated with the pathological permeabilization of the coronary vessels. The outcome of AAV-base gene therapy for MI, via Camk2d base editing, was significantly improved when AAV was injected at the third day post MI. Together, our findings uncovered a critical therapeutic time window after MI that facilitated AAV-based cardiac gene transfer, which could be harnessed to boost both basic and translational cardiology. Methods Adult C57BL/6 mice were subjected to left anterior descending (LAD) coronary artery ligation. Permanent LAD ligation created the MI model while 30min ligation followed by reperfusion established the ischemia/reperfusion (I/R) model. 2×10 11 AAV vectors were injected into the mice via tail vein. The AAV vectors carried transgenes that were activated by the cardiomyocyte-specific Tnnt2 promoter or the constitutively active CMV promoter. AAV expressed luciferase with the hemagglutinin (HA) tag. The amount of AAV vectors were quantified by real-time quantitative PCR (RT-qPCR) analysis of genomic DNA. Transgene expression was measured by RT-qPCR at the mRNA level or HA tag immunofluorescence imaging and western blot at the protein level. Luciferase activity was measured via bioluminescence imaging.