Endothelial progenitor cells (EPC) transplantation has been shown to enhance neovascularization and improve myocardial infarction (MI)-induced ventricular dysfunctions. However, persistent inflammation in the ischemic myocardium, adversely affect EPC survival and function, thereby compromising full benefits of EPC-mediated vascular repair. We hypothesized that modulation of IL-10 signaling in EPCs enhances their mobilization, survival and function in ischemic myocardium after MI. GFP-labeled EPC were transplanted intramyocardially after induction of MI, and the mice were treated with either saline or recombinant IL-10. EPC survival and EPC-mediated neovascularization and myocardial repair were evaluated. IL-10-treated mice showed increased number of GFP+EPCs retention that was associated with reduced EPC apoptosis in the myocardium (P<0.05). The engraftment of EPC into the vascular structures and the associated capillaries density was significantly higher in IL-10-treated mice (P<0.05). The above findings were corroborated with reduced infarct size, fibrosis and enhanced LV function (echocardiography) in IL-10+EPC group as compared to EPC+saline group. Invitro, IL-10-deficient EPCs showed higher LPS-induced apoptosis compared to WT-EPCs (P<0.05). IL-10 treatment induced VEGF expression in WT-EPCs which was abrogated by STAT3 inhibition (using curcurbitacin I). Furthermore, microRNA (miR) profile experiments identified significant increases in a number of pro-apoptotic and anti-angiogenic-related miRs in EPCs from IL-10 deficient mice. Interestingly, IL-10-deficient mice showed impaired MI-induced mobilization of bone marrow EPCs (Sca1+Flk1+ cells) into the circulation and the associated SDF-1 mRNA expression in the myocardium. Bone marrow transplantation studies involving replacement of IL-10-deficient marrow with WT marrow attenuated these effects. Invitro, LPS-induced CXCR4 expression was lower in IL-10-deficient EPCs as compared to WT-EPC. Taken together, our studies suggest that IL-10 enhances EPC mobilization, possibly in an SDF1-CXCR4 dependent manner and increased their survival and neovascularization and the associated myocardial repair, in part via activation of STAT3 signaling cascades.
A PEDF-Derived Peptide Inhibits Retinal Neovascularization and Blocks Mobilization of Bone Marrow-Derived Endothelial Progenitor Cells
