title: Attenuating heat-induced cellular autophagy, apoptosis and damage in H9c2 cardiomyocytes by pre-inducing HSP70 with heat shock preconditioning.
abstract: OBJECTIVE
  We sought to assess whether heat-induced autophagy, apoptosis and cell damage in H9c2 cells can be affected by pre-inducing HSP70 (heat shock protein 70).
  
  
  METHODS
  Cell viability was determined using 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide staining and a lactate dehydrogenase assay. Apoptosis was evidenced using both flow cytometry and counting caspase-3 positive cells, whereas autophagy was evidenced by the increased LC3-II expression and lysosomal activity.
  
  
  RESULTS
  The viability of H9c2 cells was temperature-dependently (40-44 °C) and time-dependently (90-180 min) significantly (p < 0.05) reduced by severe heat, which caused cell damage, apoptosis and autophagy. Heat-induced cell injury could be attenuated by pretreatment with 3-methylademine (an autophagy inhibitor) or Z-DEVD-FMK (a caspase-3 inhibitor). Neither apoptosis nor autophagy over the levels found in normothermic controls was induced in heat-shock preconditioned controls (no subsequent heat injury). The beneficial effects of mild heat preconditioning (preventing heat-induced cell damage, apoptosis and autophagy) were significantly attenuated by inhibiting HSP70 overexpression with triptolide (Tripterygium wilfordii) pretreatment.
  
  
  CONCLUSIONS
  We conclude that pre-inducing HSP70 attenuates heat-stimulated cell autophagy, apoptosis and damage in the heart. However, this requires in vivo confirmation.
authors.affiliation: Department of Nursing, Shu-Zen Junior College of Medicine and Management, Kaohsiung City, Taiwan.
authors.forename: Shu-Fen
authors.initials: SF
authors.lastname: Hsu
authors.forename: Chien-Ming
authors.initials: CM
authors.lastname: Chao
authors.forename: Wu-Tein
authors.initials: WT
authors.lastname: Huang
authors.forename: Mao-Tsun
authors.initials: MT
authors.lastname: Lin
authors.forename: Bor-Chih
authors.initials: BC
authors.lastname: Cheng
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis; D001343:Autophagy; D061945:Caspase Inhibitors / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival; D004224:Diterpenes / Q000494:pharmacology; D004852:Epoxy Compounds / Q000494:pharmacology; D018840:HSP70 Heat-Shock Proteins; D018869:Heat-Shock Response; D006358:Hot Temperature; D032383:Myocytes, Cardiac / Q000166:cytology*; D009842:Oligopeptides / Q000494:pharmacology; D010616:Phenanthrenes / Q000494:pharmacology; D051381:Rats
chemical_list: D061945:Caspase Inhibitors; D004224:Diterpenes; D004852:Epoxy Compounds; D018840:HSP70 Heat-Shock Proteins; D009842:Oligopeptides; D010616:Phenanthrenes; C110772:benzoylcarbonyl-aspartyl-glutamyl-valyl-aspartyl-fluoromethyl ketone; C001899:triptolide; C025946:3-methyladenine; D000225:Adenine