Integrin-linked kinase is required in hypoxic mesenchymal stem cells for strengthening cell adhesion to ischemic myocardium

Abstract

Mesenchymal stem cells (MSCs) therapy has limitations due to the poor viability of MSCs after cell transplantation. Integrin-mediated adhesion is a prerequisite for cell survival. As a novel anti-death strategy to improve cell survival in the infarcted heart, MSCs were genetically modified to overexpress integrin-linked kinase (ILK). The survival rate of ILK-transfected MSCs (ILK-MSCs) was augmented by about 1.5-fold and the phosphorylation of ERK1/2 and Akt in ILK-MSCs were increased by about three and twofold, respectively. ILK-MSCs demonstrated an increase of twofold in the ratio of Bcl-2/Bax and inhibited caspase-3 activation, compared with hypoxic MSCs. The adhesion rate of ILK-MSCs also had a 32.2% increase on the cardiac fibroblast-derived three-dimensional matrix and ILK-MSCs showed higher retention by about fourfold compared to unmodified MSCs. Six animals per group were used for the in vivo experiments analyzed at 1 week after occlusion of the left coronary artery. ILK-MSC transplanted rats had a 12.0% +/- 3.1% smaller infarct size than MSC-treated rats after ligation of left anterior descending coronary artery. Transplantation of ILK-MSCs not only led to a 16.0% +/- 0.4% decrease in the fibrotic heart area, but also significantly reduced the apoptotic positive index by two-thirds when compared with ligation only. The mean microvessel count per field in the infarcted myocardium of ILK-MSCs group was increased relative to the sham group and MSCs group. In conclusion, the ILK gene transduction of MSCs further assisted cell survival and adhesion, and improved myocardial damage when compared with MSC only after transplantation.