title: Inhibition of autophagy alleviates the senescent state of rat mesenchymal stem cells during long-term culture.
abstract: Following a limited number of cell divisions, mesenchymal stem cells (MSCs) undergo senescence, and these senescent cells maintain metabolic modification and remain viable for long periods. Autophagy, an intracellular bulk degradation process, provides a survival effect for cells under stress. In this study, the effect of autophagy on senescent MSCs was analyzed. Following serial passaging, rat MSCs underwent replicative senescence, characterized by positive staining for senescence-associated β-galactosidase (SA-β-gal), and increased expression levels of p16 and p21. During MSC senescence, the levels of autophagic activity were increased, a greater number of autophagic vacuoles were observed in senescent MSCs by transmission electron microscopy, acridine orange staining was elevated and the expression levels of autophagy‑related proteins (microtubule‑associated protein 1A/1B‑light chain 3-II, Atg7 and Atg12) were increased. The role of autophagy in MSC senescence was further investigated through pharmacological inhibition of autophagy with bafilomycin A1 and 3-methyladenine. Inhibition of autophagy by pharmacological means reduced the rate of positive staining for SA-β-gal and the expression levels of senescence‑related proteins. In conclusion, these findings suggest that autophagy is activated during senescence and the autophagic activity may be a requirement for maintaining the senescent state of MSCs.
authors.affiliation: Department of Anatomy and Embryology, Wuhan University School of Medicine, Wuhan, Hubei 430071, P.R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Anatomy and Embryology, Wuhan University School of Medicine, Wuhan, Hubei 430071, P.R. China.
authors.forename: Cheng-Jun
authors.initials: CJ
authors.lastname: Hu
authors.affiliation: Department of Integrated Medicine, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, P.R. China.
authors.forename: Ru-Hong
authors.initials: RH
authors.lastname: Zhuo
authors.affiliation: Department of Anatomy and Embryology, Wuhan University School of Medicine, Wuhan, Hubei 430071, P.R. China.
authors.forename: Yue-Shan
authors.initials: YS
authors.lastname: Lei
authors.affiliation: Department of Endodontics, School of Stomatology, Wuhan University, Wuhan, Hubei 430071, P.R. China.
authors.forename: Na-Na
authors.initials: NN
authors.lastname: Han
authors.affiliation: Department of Anatomy and Embryology, Wuhan University School of Medicine, Wuhan, Hubei 430071, P.R. China.
authors.forename: Liu
authors.initials: L
authors.lastname: He
mesh_terms: D000818:Animals; D001343:Autophagy / Q000502:physiology*; D000071193:Autophagy-Related Protein 7; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000502:physiology*; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000378:metabolism / Q000502:physiology*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism; D044764:Ubiquitin-Activating Enzymes / Q000378:metabolism; D001616:beta-Galactosidase / Q000378:metabolism; D054462:p21-Activated Kinases / Q000378:metabolism
chemical_list: C561242:Atg7 protein, rat; D019941:Cyclin-Dependent Kinase Inhibitor p16; D008869:Microtubule-Associated Proteins; D025841:Small Ubiquitin-Related Modifier Proteins; D054462:p21-Activated Kinases; D001616:beta-Galactosidase; D000071193:Autophagy-Related Protein 7; D044764:Ubiquitin-Activating Enzymes