Role Of Cardiomyocyte Specific Pellino-1, An E3 Ligase On Therapeutic Angiogenesis And Attenuation Of Ventricular Remodeling In A Murine Myocardial Infarction Model

Ubiquitination plays a vital role in our system in controlling vascular inflammation, cellular protein quality control, and minimizing misfolded protein toxicity. Pellino1 (Peli1), a type of E3 ubiquitin ligase, has emerged as a critical regulator of the innate immune response; however, its role in the repair and regeneration of ischemic myocardium remains to be elucidated. Materials: Cardiomyocytes isolated from Wild type (WT), cardiomyocyte-specific Peli1 overexpressed (AMPEL1Tg/+), and cardiomyocyte specific Peli1 knockout (CP1KO) mice were cultured and exposed to 6 h hypoxia, and the conditioned media (CM) collected. CMs were used to treat mouse cardiac endothelial cells (MCECs) followed by H2O2 treatment. Cells were used for Western blot, Flow cytometry, and scratch analyses. For in vivo myocardial infarction (MI) model, animals were exposed to left anterior descending artery (LAD) ligation. Animals were divided into (a) WT, (b) AMPEL1Tg/+(c) CP1KO and subjected to sham (S) and MI. Results: In vitro study documented faster wound closure and increased expression of angiogenic factors (pFlk-1, Ang-1 and VEGF) with MCECs treated with CM obtained from AMPEL1 compared to the other CM obtained from CP1KO and WT. There was no change in cardiac functions between Sham groups. AMPEL1Tg/+ MI group, showed preserved systolic functions, represented by both EF [n=12-14, p<0.0001] and FS [n=12-14, p<0.0001] compared to WTMI. However, CP1KO MI showed loss of systolic function, as represented by EF [n=13, p=0.03] and FS [n=13, p=0.03] compared to WTMI. The extent of fibrosis is also reduced in AMPEL1MI [n=5, p=0.0031], but increased in CP1KOMI [n=6-7, p<0.0001] compared to WTMI. Capillary n=4-5, p=0.0010] and arteriolar density [n=5, p=0.0005] were increased in AMPEL1MI but reduced in CP1KOMI [n=6, p<0.0001]; [n=5-7, p=0.02] compared to WTMI. Western blot analysis documented increased survival and angiogenic factors (pAKT, VEGF, and Bcl2) in AMPEL1MI compared to CP1KOMI and WTMI. Conclusion: Our study uncovers the role of cardiomyocyte-specific Peli1 as a regulator of repair and regeneration of ischemic myocardium, as evidenced by preserved cardiac function, increased expression of angiogenic factors, and reduction of apoptotic markers in the MI model.