title: SIRT5: a safeguard against oxidative stress-induced apoptosis in cardiomyocytes.
abstract: BACKGROUND
  SIRT5 is located in the mitochondria, and plays a crucial role in the regulation of metabolic process and cellular apoptosis. Cardiomyocytes are abundant in mitochondria. However, the role of SIRT5 in oxidative stress-induced apoptosis is still unknown in cardiomyocytes.
  
  
  RESULTS
  Western blots analysis revealed that SIRT5 is significantly down-regulated in cardiomyocytes upon oxidative stress. MTT assay, DAPI staining, and caspase 3/7 activity assay were used to estimate apoptosis development. The result suggested that compared with the wild-type group, SIRT5 knockdown results in a marked reduction in cell viability, and a significant increase in the number of apoptotic cells and the caspase 3/7 activity. Protein immunoprecipitation revealed a direct interaction between Bcl-Xl and SIRT5. Apoptosis assay and western blot anaylsis suggested that SIRT5 levels could affect the levels of Bcl-Xl expression, but have no effect on the apoptosis development in Bcl-Xl knockdown cells.
  
  
  CONCLUSIONS
  This study reveals a novel role of SIRT5 in the regulation of oxidative stress-induced apoptosis in cardiomyocytes. Pharmacological interventions on SIRT5 expression may be useful in the treatment of oxidative stress-related cardiac injury.
authors.affiliation: Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, P.R. China.
authors.forename: Ban
authors.initials: B
authors.lastname: Liu
authors.forename: Wenliang
authors.initials: W
authors.lastname: Che
authors.forename: Changzhu
authors.initials: C
authors.lastname: Zheng
authors.forename: Weijing
authors.initials: W
authors.lastname: Liu
authors.forename: Jing
authors.initials: J
authors.lastname: Wen
authors.forename: Haitao
authors.initials: H
authors.lastname: Fu
authors.forename: Kai
authors.initials: K
authors.lastname: Tang
authors.forename: Jinying
authors.initials: J
authors.lastname: Zhang
authors.forename: Yawei
authors.initials: Y
authors.lastname: Xu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D053179:Caspase 7 / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D006861:Hydrogen Peroxide / Q000494:pharmacology; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D037761:Sirtuins / Q000235:genetics / Q000378:metabolism*; D051020:bcl-X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D051020:bcl-X Protein; D006861:Hydrogen Peroxide; D053148:Caspase 3; D053179:Caspase 7; C530376:SIRT5 protein, rat; D037761:Sirtuins