Endothelial Progenitor Cell-Derived Microvesicles Improve Neovascularization in a Murine Model of Hindlimb Ischemia

Abstract

Paracrine mediators released from endothelial progenitor cells (EPCs) have been implicated in neoangiogenesis following ischemia. Recently, we demonstrated that microvesicles (MVs) derived from EPCs are able to activate an angiogenic program in quiescent endothelial cells by a horizontal transfer of RNA. In this study we aim to investigate whether EPC-derived MVs are able to induce neoangiogenesis and to enhance recovery in a murine model of hindlimb ischemia. Hindlimb ischemia was induced in severe combined immunodeficient (SCID) mice by ligation and resection of the left femoral artery and mice were treated with EPC-derived MVs (MVs), RNase-inactivated MVs (RnaseMVs), fibroblastderived MVs or vehicle alone as control (CTL). Since MVs contained the angiogenic miR-126 and miR-296, we evaluated whether microRNAs may account for the angiogenic activities by treating mice with MVs obtained from DICER-knock-down EPC (DICER-MVs). Peripheral arterial disease, caused by atherosclerotic occlusion of the leg arteries, is an important manifestation of systemic atherosclerosis along with coronary heart disease and cerebrovascular disease. The age-adjusted prevalence of peripheral arterial disease is approximately 12%, and affects men and women equally. The typical clinical manifestation is claudication, nevertheless 5% ofpatients undergo an amputation within 5 years (1,2).

Exosomes

“…In other situations, the injection of proangiogenic exosomes can be beneficial. For example, the previously mentioned vesicles isolated by Camussi et al 61 have been shown to induce neovascularization in a murine model of hindlimb ischemia, 72 stimulating angiogenesis by means of miRNA or mRNA transfer. 73 Protection was lost after RNAse treatment or depletion of proangiogenic miR-126 and miR-296.…”

“…73 Protection was lost after RNAse treatment or depletion of proangiogenic miR-126 and miR-296. 61,72 Human cardiomyocyte progenitor cells have also been shown to release exosomes, which can stimulate the migration of microvascular endothelial cells. 74 In an interesting recent study, human umbilical vein endothelial cells subjected to shear stress were shown to release vesicles (exosomes or microvesicles) enriched in miR-143/145, which controlled target gene expression in cocultured smooth muscle cells.…”

Evolving Role of Microparticles in the Pathophysiology of Endothelial Dysfunction

“…The effects of endothelial progenitor cell MPs are associated with the PI3K/Akt signaling pathway and eNOS activation (59 ). Treatment with endothelial progenitor cell MPs improves neovascularization and favors regeneration in severe mouse hind limb ischemia, suggesting a possible use of these MPs for treatment of peripheral arterial disease (60 ).…”

Strategies to deliver microRNAs as potential therapeutics in the treatment of cardiovascular pathology

“…Human progenitor ECs were shown to also release microvesicles containing miR-126, miR-296 and other angiogenic miRNAs (Deregibus et al, 2007). Microvesicles derived from these progenitor cells were capable to promote endothelial cell survival, proliferation, and organization in capillarylike structures in immunodeficient mice (Deregibus et al, 2007) and to induce neoangiogenesis and enhance recovery in a murine model of hindlimb ischemia (Ranghino et al, 2012). These observations suggest for a putative therapeutic potential of progenitor ECs as a source of microvesicles.…”