Gene modification with integrin-linked kinase improves function of endothelial progenitor cells in pre-eclampsia in vitro

Pivotal Cytoprotective Mediators and Promising Therapeutic Strategies for Endothelial Progenitor Cell-Based Cardiovascular Regeneration

Cardiovascular diseases (CVDs), including atherosclerosis, stroke, and myocardial infarction, is a major cause of death worldwide. In aspects of cell therapy against CVD, it is generally accepted that endothelial progenitor cells (EPCs) are potent neovascular modulators in ischemic tissues. In response to ischemic injury signals, EPCs located in a bone marrow niche migrate to injury sites and form new vessels by secreting various vasculogenic factors including VEGF, SDF-1, and FGF, as well as by directly differentiating into endothelial cells. Nonetheless, in ischemic tissues, most of engrafted EPCs do not survive under harsh ischemic conditions and nutrient depletion. Therefore, an understanding of diverse EPC-related cytoprotective mediators underlying EPC homeostasis in ischemic tissues may help to overcome current obstacles for EPC-mediated cell therapy for CVDs. Additionally, to enhance EPC's functional capacity at ischemic sites, multiple strategies for cell survival should be considered, that is, preconditioning of EPCs with function-targeting drugs including natural compounds and hormones, virus mediated genetic modification, combined therapy with other stem/progenitor cells, and conglomeration with biomaterials. In this review, we discuss multiple cytoprotective mediators of EPC-based cardiovascular repair and propose promising therapeutic strategies for the treatment of CVDs.

Intracoronary Transplantation of Mesenchymal Stem Cells with Overexpressed Integrin-Linked Kinase Improves Cardiac Function in Porcine Myocardial Infarction

The effect of mesenchymal stem cell (MSCs)-based therapy on treating acute myocardial infarction (MI) is limited due to poor engraftment and limited regenerative potential. Here we engineered MSCs with integrin-linked kinase (ILK), a pleiotropic protein critically regulating cell survival, proliferation, differentiation, and angiogenesis. We firstly combined ferumoxytol with poly-L-lysine (PLL), and found this combination promisingly enabled MRI visualization of MSCs in vitro and in vivo with good safety. We provided visually direct evidence that intracoronary ILK-MSCs had substantially enhanced homing capacity to infarct myocardium in porcine following cardiac catheterization induced MI. Intracoronary transplantation of allogeneic ILK-MSCs, but not vector-MSCs, significantly enhanced global left ventricular ejection fraction (LVEF) by 7.8% compared with baseline, by 10.3% compared with vehicles, and inhibited myocardial remodeling compared with vehicles at 15-day follow-up. Compared with vector-MSCs, ILK-MSCs significantly improved regional LV contractile function, reduced scar size, fibrosis, cell apoptosis, and increased regional myocardial perfusion and cell proliferation. This preclinical study indicates that ILK-engineered MSCs might promote the clinical translation of MSC-based therapy in post-MI patients, and provides evidence that ferumoxytol labeling of cells combined with PLL is feasible in in vivo cell tracking.

Growth arrest-specific gene 6 protein promotes the proliferation and migration of endothelial progenitor cells through the PI3K/AKT signaling pathway

Endothelial progenitor cells (EPCs) play an important role in endothelial repair and vascular regeneration. Growth arrest-specific gene 6 (Gas6) is a novel key regulator of the vascular system, which is linked to a number of cardiovascular diseases. However, the effects of Gas6 on EPCs have not been elucidated to date. The present study was designed to determine the biological function of EPCs treated with Gas6 and to eludicate the underlying mechanisms. EPCs were isolated from umbilical cord blood and treated with various concentrations (25, 50, 100 and 200 ng/ml) of Gas6. The proliferation, migration and angiogenesis of the Gas6-treated EPCs were evaluated by MTT assay, Transwell assay and in vitro tube formation assay, respectively. The phosphorylation status of AKT and ERK was evaluated by western blot analysis. The results demonstrated that treatment with Gas6 enhanced the proliferation and migration of the EPCs in a dose-dependent manner. However, Gas6 did not promote the differentiation of EPCs on Matrigel. Gas6 induced the phosphorylation of AKT, but not that of ERK. The enhanced proliferation and migration induced by Gas6 was markedly suppressed by the inhibitor of PI3K but not by that of ERK. These results suggest that Gas6 activates the AKT signaling pathway, which, in turn, promotes the proliferation and migration of EPCs.

Ultrasound microbubble-mediated delivery of integrin-linked kinase gene improves endothelial progenitor cells dysfunction in pre-eclampsia

Pre-eclampsia (PE) is a specific vascular complication in pregnancy whose precise mechanism is still unclear. We hypothesized that endothelial progenitor cells (EPCs), the precursor of endothelial cells, might be impaired in patients with PE and hold a great promise for the treatment of PE. In the present study, we analyzed the EPCs number and expression of integrin-linked kinase (ILK) in PE patients. We confirmed that both EPCs number and ILK expression were diminished in PE patients. Next, we transfected EPCs with ILK gene using ultrasonic microbubble technique (UMT) for the first time, as UMT is a novel type of gene transfer technology showing promising applications in stem cells apart from EPCs. To further investigate the transfection efficiency of UMT, RT-PCR analysis and western blot were used to examine the messenger RNA (mRNA) and protein level of ILK. After transfection of the ILK gene, EPCs function was tested to illustrate the role of ILK in cell proliferation, apoptosis, migration, and secretion. The results of the in vitro study suggested that UMT, a novel gene delivery system, could be considered a potent physical method for EPCs transfection. Moreover, the growth and angiogenetic properties of EPCs are enhanced by introducing ILK. This study may afford a new trend for EPCs transfection and gene therapy in PE.

Review: Endothelial progenitor cells in pregnancy and obstetric pathologies

Since their discovery, endothelial progenitor cells (EPCs) have generated considerable interest in vascular biology. They are a heterogeneous population of cells that exist in both the fetus and adult, and are mobilized to support de novo vessel formation or encourage vascular health. This review summarizes our understanding of these cells in pregnancy, paying particular attention to their physiological role in placental development and the uterus, alongside their involvement in related obstetric pathologies.