Effect of Oxidative Stress-Induced Autophagy on Proliferation and Apoptosis of hMSCs

Abstract

Background:Objective:To observe the effect of H2O2 induced oxidative stress on autophagy and apoptosis of human bone marrow mesenchymal stem cells (hBMSCs).Method: The hBMSCs were separated and cultured by density gradient centrifugation combined with adherence method. They were divided into blank group (with medium only), 3-MA (autophagy inhibitor) pretreatment group (with 2 ml of 5 mM 3-MA medium), H2O2 Intervention group (add 2ml medium containing 0.05mM H2O2), H2O2+3-MA treatment group (add 2ml medium containing 5mM 3-MA, then add 2ml medium containing 0.05mM H2O2). DCFH-DA staining was used to detect cellular reactive oxygen species (ROS) levels,and CCK-8 analysis was used to detect the effects of different concentrations (0,50,100,200,400μmol/L) of H2O2 on the proliferation of hBMSCs; Monodansylcadaverine(MDC) Fluorescent amine probe staining, Lysosome Red Fluorescent Probe (Lyso-Tracker Red) staining to observe the level of autophagy; Immunofluorescence staining to detect the expression of LC3A/B; Flow cytometry (Annexin V/PI) to detect cell apoptosis Circumstances; Protein chip detection of autophagy-related proteins; Western blot detection of Beclin1, mTOR, p-mTOR, LC3A/B, and Cleaved caspase-3 protein expression.Result: After treating hBMSCs with different concentrations of H2O2 (0,50,100,200,400μmol) for 24h ,48h, and 72h, with the increase of H2O2 concentration, the cell proliferation ability decreased; while with the extension of time, the cell proliferation ability increased not significantly; 50μmol cell proliferation ability is the strongest. Compared with the blank group and 3-MA group, the H2O2 intervention group increased the level of intracellular ROS, increased autophagosomes, and significantly decreased the apoptosis rate; up-regulated Beclin1, mTOR, LC3A/B and Cleaved caspase-3 protein expression, and down-regulated p-mTOR Protein expression level. Compared with the autophagy inhibitor 3-MA group, the H2O2+3-MA group increased the level of intracellular ROS, increased autophagosomes, and did not significantly increase the apoptosis rate; up-regulated the protein expression of Beclin1, mTOR, LC3A/B and Cleaved caspase-3 Down-regulate the expression of p-mTOR protein.Conclusion: H2O2 can induce hMSCs to produce oxidative stress response. Under oxidative stress conditions, hMSCs can promote protective autophagy and reduce cell apoptosis or the level of apoptosis caused by excessive autophagy.