title: Target disruption of ribosomal protein pNO40 accelerates aging and impairs osteogenic differentiation of mesenchymal stem cells.
abstract: pNO40/PS1D, a novel nucleolar protein, has been characterized as a core protein of eukaryotic 60S ribosome and at least two splicing forms of pNO40 mRNAs with alternative starting sites have been identified. Through production of knockout (ko) mice with either exon 2 (△E2), exon 4 (△E4) or △E2+E4 targeted disruption we identified a cryptic splicing product occurring in the ko tissues examined which in general cannot be observed in regular RT-PCR detection of wild-type (wt) animals. Among ko animals, △E4 null embryos exhibited prominent senescence-associated β-galactosidase (SA-β-gal) staining, a marker for senescent cells, in notochord, forelimbs and heart while bone marrow-derived mesenchymal stem cells (MSCs) from △E4 null mice developed accelerated aging and osteogenic differentiation defects compared to those from wt and other isoform mutant mice. Examination of the causal relationship between pNO40 deficiency and MSC-accelerated aging revealed △E4 null disruption in MSCs elicits high levels of ROS and elevated expression levels of p16 and Rb but not p53. Further analysis with iTraq identified CYP1B1, a component of the cytochrome p450 system, as a potential molecule mediating ROS generation in pNO40 deficient MSCs. We herein established a mouse model of MSC aging through pNO40-targeted depletion and demonstrated the effects of loss of pNO40 on bone homeostasis.
authors.affiliation: Department of Anatomy, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Yen-Ming
authors.initials: YM
authors.lastname: Lin
authors.affiliation: Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Chih-Ching
authors.initials: CC
authors.lastname: Wu
authors.affiliation: Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Nuclear Medicine and Molecular Imaging Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
authors.forename: Yu-Chen
authors.initials: YC
authors.lastname: Chang
authors.affiliation: Department of Anatomy, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Chu-Han
authors.initials: CH
authors.lastname: Wu
authors.affiliation: Department of Anatomy, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Hsien Li
authors.initials: HL
authors.lastname: Ho
authors.affiliation: Gene Engineered Mice Core Lab, Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Ji Wei
authors.initials: JW
authors.lastname: Hu
authors.affiliation: Department of Anatomy, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Ren-Chi
authors.initials: RC
authors.lastname: Chang
authors.affiliation: Department of Anatomy, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Chung-Ta
authors.initials: CT
authors.lastname: Wang
authors.affiliation: Department of Anatomy, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Gene Engineered Mice Core Lab, Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan. Electronic address: ouyang@mail.cgu.edu.tw.
authors.forename: Pin
authors.initials: P
authors.lastname: Ouyang
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000502:physiology*; D065633:Cytochrome P-450 CYP1B1 / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010006:Osteoblasts / Q000166:cytology* / Q000502:physiology; D010012:Osteogenesis / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D009687:Nuclear Proteins; D017382:Reactive Oxygen Species; C476768:pNO40 protein, mouse; C585498:Cyp1b1 protein, mouse; D065633:Cytochrome P-450 CYP1B1
keywords: Aging; Knockout mice; Mesenchymal stem cells; Osteogenesis; pNO40