title: Downregulation of B-myb promotes senescence via the ROS-mediated p53/p21 pathway, in vascular endothelial cells.
abstract: OBJECTIVE
  To reveal whether B-myb is involved in preventing senescence of vascular endothelial cells, and if so, to identify possible mechanisms for it.
  
  
  METHODS
  C57/BL6 male mice and primary human aortic endothelial cells (HAECs) were used. Bleomycin was applied to induce stress-related premature senescence. B-myb knockdown was achieved using an siRNA technique and cell senescence was assessed using the senescence-associated β-galactosidase (SA-β-gal) assay. Intracellular reactive oxygen species (ROS) production was analysed using an ROS assay kit and cell proliferation was evaluated using KFluor488 EdU kit. Capillary tube network formation was determined by Matrigel assay. Expressions of mRNA and protein levels were detected by real-time PCR and western blotting.
  
  
  RESULTS
  B-myb expression significantly decreased, while p53 and p21 expressions increased in the aortas of aged mice. This expression pattern was also found in replicative senescent HAECs and senescent HAECs induced by bleomycin. B-myb knockdown resulted in upregulation of p22phox, ROS accumulation and cell senescence of HAECs. Downregulation of B-myb significantly inhibited cell proliferation and capillary tube network formation and activated the p53/p21 signalling pathway. Blocking ROS production or inhibiting p53 activation remarkably attenuated SA-β-gal activity and delayed cell senescence induced by B-myb-silencing.
  
  
  CONCLUSIONS
  Downregulation of B-myb induced senescence by upregulation of p22phoxand activation of the ROS/p53/p21 pathway, in our vascular endothelial cells, suggesting that B-myb may be a novel candidate for regulating cell senescence to protect against endothelial senescence-related cardiovascular diseases.
authors.affiliation: Department of Cardiology, Shanghai East Hospital and Immunology Department, Tongji University School of Medicine, Shanghai, China.
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Department of Cardiology, Shanghai East Hospital and Immunology Department, Tongji University School of Medicine, Shanghai, China.
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Yin
authors.affiliation: Department of Cardiology, Shanghai East Hospital and Immunology Department, Tongji University School of Medicine, Shanghai, China.
authors.forename: Qun
authors.initials: Q
authors.lastname: Chang
authors.affiliation: Department of Cardiology, Shanghai East Hospital and Immunology Department, Tongji University School of Medicine, Shanghai, China.
authors.forename: Guanqun
authors.initials: G
authors.lastname: Sun
authors.affiliation: Department of Cardiology, Shanghai East Hospital and Immunology Department, Tongji University School of Medicine, Shanghai, China.
authors.forename: Jiahui
authors.initials: J
authors.lastname: Lin
authors.affiliation: Department of Cardiology, Shanghai East Hospital and Immunology Department, Tongji University School of Medicine, Shanghai, China.
authors.forename: Yalei
authors.initials: Y
authors.lastname: Dai
mesh_terms: D000818:Animals; D018797:Cell Cycle Proteins / Q000378:metabolism*; D049109:Cell Proliferation / Q000502:physiology*; D016922:Cellular Senescence / Q000502:physiology; D015536:Down-Regulation; D042783:Endothelial Cells / Q000378:metabolism*; D008297:Male; D008810:Mice, Inbred C57BL; D034741:RNA, Small Interfering / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D015534:Trans-Activators / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; C499306:Mybl2 protein, mouse; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D015534:Trans-Activators; D016159:Tumor Suppressor Protein p53