Abstract 17923: Hypoxia Inducible Factor-1α Dependent miR-210 is a Critical Regulator of Paracrine Activity in Preconditioned Mesenchymal Stem Cells for Angiogenic Growth Factor Expression
Background: We have previously reported that miR-210 was critical for hypoxia inducible factor-1α (HIF-1α) dependent cytoprotective effects of ischemic pre-conditioning (IPC) of stem cells by 2 cycles of intermittent 30 minutes ischemia/reoxygenation (I/R). Given that HIF-1 α is a master regulator of multiple angiogenic growth factors, we hypothesized a possible role for miR-210 in regulation of the paracrine behavior of preconditioned mesenchymal stem cells (PCMSCs).
Methods and Results: MSCs were isolated from young male Fischer-344 rats by flushing the cavity of femur and propagated in vitro following our optimized protocol. These cells were then preconditioned by intermittent 2 cycles of 30 minutes I/R which showed significant activation of HIF-1α (p<0.01) and miR-210 expression (p<0.01) as compared to native MSCs (NatMSCs). HIF-1α specific siRNA in PCMSCs abrogated the expression of miR-210. We also observed altered expression level of multiple angiogenic growth factors in PCMSCs significant amongst which included angiopoietin-1 (Ang-1), vascular endothelial growth factor (VEGF), fibroblast growth factor-2 and Netrin-2. Transfection of NatMSCs with miR-210 plasmid (pEZX-GFP-miR-210) simulated the effects of preconditioning and enhanced Vegf (2.3 fold) and Ang-1 (2.1 fold) expression while abrogation of miR-210 with specific inhibitor significantly reduced expression of both VEGF and Ang-1.Tube formation on Matrigel surface and Trans-well cell migration assays showed significantly enhanced branch points and HUVEC cell migration in response to treatment with conditioned media from PCMSCs and MSCs over-expressing miR-210. These effects during in vitro angiogenic response assays were abolished in PCMSCs transfected with anti-miR-210 (p<0.05 vs PCMSCs).
Conclusion: miR-210 is a critical regulator of the paracrine activity in PCMSCs for the release of HIF-1α dependent secretable growth factors.
- © 2010 by American Heart Association, Inc.