Recombinant AAV-PR39-mediated hypoxia-inducible factor 1α gene expression attenuates myocardial infarction.

PR39 is an angiogenic masterswitch protein, belonging to the second generation of angiogenic growth factors. However, the role of recombinant adeno-associated virus (AAV) carrying the PR39 fusion gene (AAV-PR39) in acute myocardial infarction remains unclear. Therefore, in this study, we investigated the role of AAV-PR39 in an experimental animal model of acute myocardial infarction. The PR39 gene was fused with the transmembrane peptide, TAT, 6xHis‑tag and NT4 signal sequences. AAV-PR39 was then obtained by calcium phosphate co-precipitation. A total of 18 healthy Chinese mini pigs were randomly divided into an experimental groups (the AAV-PR39-treated group) and a control group [phosphated-buffered saline (PBS)-treated group]. Following the induction of myocardial infarction, enhanced 3.0T MR imaging was performed to observe the changes in myocardial signal intensity at 0 h, 1, 2 and 3 weeks. The expression of hypoxia-inducible factor‑1α (HIF-1α) in the myocardial tissues was determined by SABC immunohistochemistry. In addition, in vitro experiments using CRL-1730 endothelial cells transfected with AAV vector containing NT4-TAT-His-PR39 revealed that the AAV-PR39-treated group had a significantly higher expression of HIF-1α compared with the control group. Moreover, PR39 regulated the HIF-1α-induced expression of angiogenic growth factors. Under hypoxic conditions, the anti-apoptotic effects in the AAV-PR39 group were more pronounced than those observed in the control (PBS-treated) group. In vivo, the enforced expression of recombinant PR39 elevated the level of HIF-1α under hypoxic conditions and decreased the size of the infarcted areas by upregulating the expression of HIF-1α in the areas surrounding the infarct area. Taken together, our data demonstrate that the recombinant AAV-PR39-mediated HIF-1α expression attenuates myocardial infarction, indicating that AAV-PR39 may serve as a novel therapeutic agent for the treatment of myocardial infarction.