title: Rat induced pluripotent stem cells protect H9C2 cells from cellular senescence via a paracrine mechanism.
abstract: OBJECTIVE
  Cellular senescence may play an important role in the pathology of heart aging. We aimed to explore whether induced pluripotent stem cells (iPSCs) could inhibit cardiac cellular senescence via a paracrine mechanism.
  
  
  METHODS
  We collected iPSC culture supernatant, with or without oxidative stress, as conditioned medium (CM) for the rat cardiomyocyte-derived cell line H9C2. Then we treated H9C2 cells, cultured with or without CM, with hypoxia/reoxygenation to induce cellular senescence and measured senescence-associated β-galactosidase (SA-β-gal) activity, G1 cell proportion and expression of the cell cycle regulators p16(INK4a), p21(Waf1/Cip1) and p53 at mRNA and protein levels in H9C2 cells. In addition, we used Luminex-based analysis to measure concentrations of trophic factors in iPSC-derived CM.
  
  
  RESULTS
  We found that iPSC-derived CM reduced SA-β-gal activity, attenuated G1 cell cycle arrest and reduced the expression of p16(INK4a), p21(Waf1/Cip1) and p53 in H9C2 cells. Furthermore, the CM contained more trophic factors, e.g. tissue inhibitor of metalloproteinase-1 and vascular endothelial growth factor, than H9C2-derived CM.
  
  
  CONCLUSIONS
  Paracrine factors released from iPSCs prevent stress-induced senescence of H9C2 cells by inhibiting p53-p21 and p16-pRb pathways. This is the first report demonstrating that antisenescence effects of stem cell therapy may be a novel therapeutic strategy for age-related cardiovascular disease.
authors.affiliation: Department of Cardiology, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou, China.
authors.forename: Yuzhen
authors.initials: Y
authors.lastname: Zhang
authors.forename: Dan
authors.initials: D
authors.lastname: Wang
authors.forename: Kejiang
authors.initials: K
authors.lastname: Cao
authors.forename: Minglong
authors.initials: M
authors.lastname: Chen
authors.forename: Xiangjun
authors.initials: X
authors.lastname: Yang
authors.forename: Yanyun
authors.initials: Y
authors.lastname: Tao
mesh_terms: D000818:Animals; D002460:Cell Line; D016922:Cellular Senescence; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D059585:G1 Phase Cell Cycle Checkpoints; D015870:Gene Expression; D019942:Genes, p16; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000502:physiology*; D019899:Paracrine Communication; D039904:Pluripotent Stem Cells / Q000502:physiology*; D051381:Rats; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D036341:Intercellular Signaling Peptides and Proteins; D016159:Tumor Suppressor Protein p53; D001616:beta-Galactosidase