Abstract 17939: Stem Cells With Transgenic Overexpression of Mir-210 Are Resistant to Ischemic Injury and Contributes to the Functional Recovery of Ischemic Heart
Background: We have previously shown a pro-survival effect of ischemic preconditioning (IPC) of stem cells via miR-210 expression by targeting caspase 8-associated protein-2 in response to hypoxia-inducible factor-1α activation. We hypothesized that pro-survival effects of IPC may be simulated by modification of stem cells by transgenic expression of mir-210 transplantation of which recovered myocardial function of ischemic heart.
Methods and Results: Bone marrow mesenchymal stem cells (MSCs) isolated from young male Fisher-344 were preconditioned by intermittent 2 cycles of 30 minutes ischemia/re-oxygenation. miR microarray profiling supported by qRT-PCR and in situ hybridization showed upregulation of miR-210 in preconditioned MSCs (IPCMSCs) as compared to native MSCs (NatMSCs, p<0.01). Acute phase transplantation of IPCMSCs into the infarcted rat heart significantly attenuated infarction size expansion and improved heart functions through angiomyogenesis as examined by echocardiography and immunohistochemical analyses. To examine whether induction of miR-210 dictates the beneficial effects of IPC, NatMSCs were transfected with miR-210 plasmid (pEZX-GFP-miR-210). MSCs with transgenic overexpression of miR-210 (miRMSCs) indicated higher survival rate in vitro under anoxia when compared to scramble miR transfected MSCs (scrMSCs) as examined by LDH assay and TUNEL. PCR for sry-gene expression 7 days after engraftment of male miRMSCs into female rat heart model of permanent coronary artery ligation showed improved donor cell survival (p<0.05 vs scrMSCs). Echocardiography revealed improved heart function indices including ejection fraction and fractional shortening at 4 weeks after miRMSCs transplantation (20.3±5.7 and 31.5±3.8 increases, p<0.05 vs scrMSCs respectively). Immunohistochemistry for myosin heavy chain, actinin, connexin-43 showed extensive engraftment and myogenic differentiation of miRMSCs together with increased capillary density, arteriogenesis and markedly attenuated infarction size.
Conclusion: Pro-survival effects of IPC can be simulated by ex-vivo manipulation of stem cells for overexpression of miR-210 expression which is a novel strategy for cell-based therapy of the ischemic heart.
- © 2010 by American Heart Association, Inc.