The therapeutic potential of autologous stem cell transplantation for heart repair diminishes in the elderly due to stem cell aging. Rejuvenating aged stem cells to enhance their protective effects on injured cardiomyocytes is crucial for aging patients with heart failure. In this study, we aimed to investigate whether neuron-derived neurotrophic factor (NDNF) over-expression improves the protective effect of aged stem cells for injured cardiomyocytes and explore the underlying mechanism. Human bone marrow was collected from both young and old patients, and bone marrow mesenchymal stem cells (BMSCs) were cultured. Lentivirus expression vectors carrying NDNF genes were used to transfect aged BMSCs. Fatal hypoxia-induced injury in H9C2 cells served as an in vitro ischemia model. The conditioned medium from different BMSC groups was applied to assess the beneficial effects on hypoxia-induced damage in myocardial H9C2 cells. Results revealed that the conditioned medium of NDNF over-expressed old BMSCs increased H9C2 cell viability and reduced oxidative stress and apoptosis levels under fatal hypoxia. NDNF over-expressed old BMSCs exhibited an antiapoptotic role by upregulating the antiapoptotic gene Bcl-2 and downregulating the proapoptotic genes Bax. Additionally, the protective effects were mediated through the elevation of phosphorylated AKT. Our data support the promise of NDNF as a potential target to enhance the protective effects of autologous aged BMSCs on ischemic cardiomyocytes and then improve the curative effects of stem cell for ischemic heart injury in aged patients.
Keywords: NDNF; aged hBMSCs; apoptosis; cytoprotection; oxidative stress.