title: Ameliorating replicative senescence of human bone marrow stromal cells by PSMB5 overexpression.
abstract: Multipotent human bone marrow stromal cells (hBMSCs) potentially serve as a source for cell-based therapy in regenerative medicine. However, in vitro expansion was inescapably accompanied with cell senescence, characterized by inhibited proliferation and compromised pluripotency. We have previously demonstrated that this aging process is closely associated with reduced 20S proteasomal activity, with down-regulation of rate-limiting catalytic β-subunits particularly evident. In the present study, we confirmed that proteasomal activity directly contributes to senescence of hBMSCs, which could be reversed by overexpression of the β5-subunit (PSMB5). Knocking down PSMB5 led to decreased proteasomal activity concurrent with reduced cell proliferation in early-stage hBMSCs, which is similar to the senescent phenotype observed in late-stage cells. In contrast, overexpressing PSMB5 in late-stage cells efficiently restored the normal activity of 20S proteasomes and promoted cell growth, possibly via upregulating the Cyclin D1/CDK4 complex. Additionally, PSMB5 could enhance cell resistance to oxidative stress, as evidenced by the increased cell survival upon exposing senescent hBMSCs to hydrogen peroxide. Furthermore, PSMB5 overexpression retained the pluripotency of late-stage hBMSCs by facilitating their neural differentiation both in vitro and in vivo. Collectively, our work reveals a critical role of PSMB5 in 20S proteasome-mediated protection against replicative senescence, pointing to a possible strategy for maintaining the integrity of culture-expanded hBMSCs by manipulating the expression of PSMB5.
authors.affiliation: Department of Anatomy, Shanxi Medical University, Taiyuan 030001, China. Electronic address: luli7300@126.com.
authors.forename: Li
authors.initials: L
authors.lastname: Lu
authors.affiliation: Department of Anatomy, Shanxi Medical University, Taiyuan 030001, China.
authors.forename: Hui-Fang
authors.initials: HF
authors.lastname: Song
authors.affiliation: Department of Anatomy, Shanxi Medical University, Taiyuan 030001, China.
authors.forename: Jiao-Long
authors.initials: JL
authors.lastname: Wei
authors.affiliation: Department of Anatomy, Shanxi Medical University, Taiyuan 030001, China.
authors.forename: Xue-Qin
authors.initials: XQ
authors.lastname: Liu
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital of Shanxi Medical University, Taiyuan 030001, China.
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Song
authors.affiliation: Department of Anatomy, Shanxi Medical University, Taiyuan 030001, China.
authors.forename: Ba-Yi
authors.initials: BY
authors.lastname: Yan
authors.affiliation: Department of Anatomy, Shanxi Medical University, Taiyuan 030001, China.
authors.forename: Gui-Jiao
authors.initials: GJ
authors.lastname: Yang
authors.affiliation: Department of Medicine, University of Hong Kong Faculty of Medicine, Hong Kong, China; Department of Anatomy, University of Hong Kong Faculty of Medicine, Hong Kong, China.
authors.forename: Ang
authors.initials: A
authors.lastname: Li
authors.affiliation: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China; Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium (SBIC), Agency for Science, Technology and Research (A∗STAR), Singapore. Electronic address: wulinyoung@163.com.
authors.forename: Wu-Lin
authors.initials: WL
authors.lastname: Yang
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D016922:Cellular Senescence / Q000235:genetics / Q000502:physiology; D019938:Cyclin D1 / Q000378:metabolism; D051358:Cyclin-Dependent Kinase 4 / Q000378:metabolism; D055785:Gene Knockdown Techniques; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D018384:Oxidative Stress; D046988:Proteasome Endopeptidase Complex / Q000235:genetics* / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: C530104:CCND1 protein, human; D019938:Cyclin D1; C495900:CDK4 protein, human; D051358:Cyclin-Dependent Kinase 4; C088874:PSMB5 protein, human; D046988:Proteasome Endopeptidase Complex
keywords: Bone marrow stromal cell; PSMB5; Proteasome; Replicative senescence