Abstract 10728: MicroRNA-377 Regulates Angiogenesis by Targeting VEGF: Implications for Mesenchymal Stem Cells Based Therapy in Ischemic Heart Disease
Background and Objective: MicroRNAs are involved in various critical cell functions, including regulation of angiogenesis. We hypothesized that miRNA-377 directly down-regulates VEGF in mesenchymal stem cells (MSC) and silence of miRNA-377 in MSC can enhance angiogenesis and protect heart in MSC-treated IHD.
Methods and Results: Using microRNA microarrays, we analyzed miRNA expression in MSC and firstly found that among all miRNAs miR-377 was decreased most significantly by hypoxia, a major inducer of VEGF (Fig. 1A). Our bioinformatics analysis revealed that VEGF is accidently a direct target of miR-377. Dual-luciferase reporter assay confirmed that miR-377 can bind specifically with a conserved site at 3’-UTR of VEGF. Real time PCR and Western blot showed that miR-377 suppressed VEGF expression, while miR-377 inhibitor enhanced VEGF expression. Importantly, enhanced tube formation was also observed in vitro when miR-377 was silenced (Fig.1B). To investigate the miRNA-377 role on regulating angiogenesis in vivo, miR-377-overexpressing MSC (MSC+miR-377) and miR-377-suppressing MSC (MSC-miR-377) were injected into rat infarcted myocardium, and MSC with lentiviral empty vector (MSCNull) served as control. Immunofluorescence staining showed that vessel density reduced in MSC+miR-377 group but increased in MSC-miR-377 group compared with MSCNull group (Fig. 1D). Masson’s Trichrome staining showed that LV infarction size increased in MSC+miR-377 group but reduced in MSC-miR-377 group compared with MSCNull group (Fig. 1C). Echocardiography showed pronounced improvement of cardiac function in MSC-miR-377 group compared with MSCNull group and MSC+miR-377 group (Fig. 1D).
Conclusion: MiR-377 down-regulates VEGF in MSC directly, and MSC with knock-down of miR-377 promote angiogenesis and cardiac protection against ischemic injury. MiR-377 serves as a novel therapeutic target for stem cell based treatment of IHD.
- © 2013 by American Heart Association, Inc.