Cross Talk of Combined Gene and Cell Therapy in Ischemic Heart Disease

Abstract

Background Despite the promise shown by stem cells for restoration of cardiac function following myocardial infarction (MI), the poor survival of transplanted cells has been a major issue. Hypoxia inducible factor-1 (HIF-1) is a transcription factor that mediates adaptive responses to ischemia. Here we hypothesize that co-delivery of cardiac progenitor cells (CPCs) with a nonviral minicircle plasmid carrying HIF-1 (MC-HIF1) into the ischemic myocardium can improve the survival of transplanted CPCs. Methods and Results Following MI, CPCs were co-delivered intramyocardially into adult NOD/SCID mice with either saline, MC-GFP, or MC-HIF1 versus MC-HIF1 alone (N=10/group). Bioluminescence imaging (BLI) demonstrated better survival when CPCs were co-delivered with MC-HIF1. Importantly, echocardiography showed mice injected with CPCs + MC-HIF1 had the highest ejection fraction 6 weeks post-MI (57.1±2.6%) followed by MC-HIF1 alone (48.5±2.6%), with no significant protection for CPCs + MC-GFP (44.8±3.3%) compared to saline control (38.7±3.2%, P<0.05). In vitro mechanistic studies confirmed that cardiac endothelial cells (ECs) produced exosomes which were actively internalized by recipient CPCs. Exosomes purified from ECs overexpressing HIF-1 had higher contents of miR-126 and miR-210. These microRNAs activated pro-survival kinases and induced a glycolytic switch in recipient CPCs, giving them increased tolerance when subjected to in vitro hypoxic stress. Inhibiting both of these miRs blocked the protective effects of the exosomes. Conclusions In summary, HIF-1 can be used to modulate the host microenvironment for improving survival of transplanted cells. The exosomal transfer of miRs from host cells to transplanted cells represents a unique mechanism that can be potentially targeted for improving survival of transplanted cells.

Circulating Plasma Extracellular Microvesicle MicroRNA Cargo and Endothelial Dysfunction in Children with Obstructive Sleep Apnea

“…The transfected exosome pellets were suspended in 300 ml 1 3 phosphate buffered saline, and used in the ECIS system for the miRNA mimics and inhibitors of interest (75 ml were added to approximately 5 3 10 5 cells/well in a 12-well culture plate grown in exosome-depleted fetal bovine serum), and reaching equivalent exosome concentrations across conditions (27)(28)(29)(30). miRNA mimics and inhibitors were purchased from Life Technologies (Grand Island, NY).…”

Towards the standardization of stem cell therapy studies for ischemic heart diseases: Bridging the gap between animal models and the clinical setting

“…The majority of the investigations sought to enhance the expression of a certain gene [23,24,61,63,66,74,76,102,104,109,110,117] or to transfect cells with microRNAs (miRs) [16,19]. The only example of gene repression was reported by Wang et al [39], who described the silencing of prolyl hydroxylase domain protein 2 gene (PHD2) as an alternative combined genetic and cell therapy approach.…”

Role of exosomes and microvesicles in hypoxia‐associated tumour development and cardiovascular disease

“…Of note, a specific role of hypoxia in modulating the regenerative potential of exosomes was suggested by the increased angiogenic and antifibrotic potential of CPC-exosomes isolated from CPCs grown in hypoxic compared with normoxic conditions. The effect of exosomes isolated from endothelial cells overexpressing HIF-1 on the survival of transplanted CPCs was evaluated to determine the hypoxia-dependent microenvironmental regulation of cell engraftment [78]. Exosome treatment resulted in activation of ERK and AKT phosphorylation, reduced mitochondrial metabolism and increased intracellular lactate levels, indicating the presence of a glycolytic switch in recipient CPCs.…”