The Function Of Reactive Oxygen Species In Mouse Induced Pluripotent Stem Cells

Induced pluripotent stem cells （iPSCs） are a novel stem cellpopulation induced from mouse and human adult somatic cells throughreprogramming by transduction of four defined transcription factors. Inthis study, we generated iPSCs from mouse embryonic fibroblasts cells（MEFs） with the same four factors: Oct3/4, Sox2, Klf4and c-Myc.iPSCs are a promising cell source for stem cell therapy. Reactiveoxygen species （ROS） are biologically active species that play majorroles in vascular biology through redox signaling. It is reported thatalthough excess amounts of ROS are toxic to stem cells, optimal levels ofROS are involved in normal stem cell functions. However, the role ofROS in iPSCs and how ROS affects iPSC trafficking remain unknown.In this research, we investigated ROS function in mouse iPSCs by24-h treatmentwith exogenous hydrogen peroxide （H₂O₂） and antioxidantN-acetyl-L-cysteine （NAC）. After removing MEFs, the functions ofiPSCs, including proliferation, apoptosis, cell cycle, migration, adhesion,senescence and autophagy, were further investigated.It was found that both exogenous H₂O₂and antioxidant NAC impairedcell adhesion, and induced apoptosis and senescence of iPSCs. NAC inhibited migration and transendothelial migration of iPSCs.Administered with H₂O₂for24h, some antioxidant genes weresignificantly increased, which may underlie the protective mechanism ofiPSCs in response to oxidative stress. In a mouse hindlimbischemia/reperfusion injury model, intravenously administered iPSCsselectively homed to the ischemic tissue and improved blood perfusionand limb function, while NAC-or H₂O₂-pretreated iPSCs did not show thisfunction. These results indicated that either increased or decreased ROSlevels damaged iPSC function. ROS-facilitated iPSC trafficking isessential for the therapeutic effect.