Cell Survival Effects of Autophagy Regulation on Umbilical Cord-Derived Mesenchymal Stem Cells Following Exposure to Oxidative Stress

BACKGROUND: Due to oxidative stress, hypoxia, and serum deprivation, a large percentage of mesenchymal stem cells (MSCs) die in the early stages of transplantation. The present study aimed to address whether induction or inhibition of autophagy would affect the viability of MSCs after exposure to oxidative stress. METHODS: MSCs were isolated from umbilical cord tissue using the Ficoll gradient method. pCMV-GFP-LC-3 plasmid containing GFP-tagged LC3 was transfected into MSCs to assay autophagy level in these valuable cells. The four study groups were: MSC-LC3-Rapa, MSC-LC3-3MA, MSCs without any transfection, and MSC-GFP-LC3 (control groups). To induce autophagy, the MSC-GFP-LC3 was treated with different concentrations of Rapa for 24 hours and named MSC-LC3-Rapa. To inhibit autophagy in MSC-GFP-LC3, these cells were cultured in the presence of 3MA for 24 hours and named MSC-LC3-3MA. Non-treated MSC-GFP-LC3 and MSCs were considered as control groups. MSCs were exposed to lethal doses of H(2)O(2) followed by cell viability evaluation with the water-soluble tetrazolium salt assay method. The data were analyzed with SPSS version 18.0 using one-way ANOVA test. P<0.05 was considered statistically significant. RESULTS: The results revealed that the enhancement of autophagy in MSC-LC3-Rapa sensitized them against oxidative stress (P=0.0006) and inhibition of autophagy in MSC-LC3-3MA led to resistance against oxidative stress (P=0.0003). CONCLUSION: Inhibition of autophagy, as a non-genetic engineering method, in MSCs enhances cell viability following exposure to the oxidative stress. This may provide a novel strategy to promote the efficiency of MSC-based cell therapy for clinical applications.