title: Helix B Surface Peptide Protects Cardiomyocytes Against Hypoxia/Reoxygenation-induced Apoptosis Through Mitochondrial Pathways.
abstract: Helix B surface peptide (HBSP), a newly developed tissue-protective erythropoietin derivative, has beneficial effects on myocardial ischemia. This study aimed to investigate the cardio-protective effects of HBSP against hypoxia/reoxygenation (H/R) injury and its possible mechanism.
  
  
  
  A rat-derived cardiomyocyte cell line (H9C2 cells) were established and pretreated with HBSP. The pretreated primary cultures were subjected to H/R and monitored for cell viability using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Intracellular reactive oxygen species (ROS) levels, apoptosis, and mitochondrial membrane potential (ΔΨm) were detected by flow cytometry. The expression of cytochrome C and Bcl-2 family proteins, as well as the activities of caspases 3 and 9 were determined by Western blot analysis and a colorimetric method, respectively.
  
  
  
  HBSP reduced apoptotic cells in cardiomyocytes subjected to H/R. In HBSP-treated cardiomyocytes, the H/R-induced mitochondrial ROS production, ΔΨm collapse, and cytochrome C release from mitochondria to the cytosol significantly decreased. Moreover, HBSP inhibited the activation of caspases 9 and 3, as well as the alteration of Bcl-2 family proteins, which were induced by H/R.
  
  
  
  These results indicated that HBSP has protective effects against H/R-induced apoptosis by regulating the mitochondrial pathway. This mechanism involves inhibiting mitochondrial ROS generation, inhibiting caspase-3 activity, reducing ΔΨm collapse, reducing cytochrome release, and balancing anti and proapoptotic Bcl-2 family proteins.
authors.affiliation: *Department of Cardiology, Zhujiang Hospital of Southern Medical University, Guangzhou, China; and †Department of Cardiology, The First Hospital of QinHuangDao, QinHuangDao, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Liu
authors.forename: Yongluan
authors.initials: Y
authors.lastname: Lin
authors.forename: Xiuying
authors.initials: X
authors.lastname: Tang
authors.forename: Peidong
authors.initials: P
authors.lastname: Zhang
authors.forename: Bei
authors.initials: B
authors.lastname: Liu
authors.forename: Yingfeng
authors.initials: Y
authors.lastname: Liu
authors.forename: Fei
authors.initials: F
authors.lastname: Miao
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D015687:Cell Hypoxia / Q000187:drug effects*; D045304:Cytochromes c / Q000378:metabolism; D004921:Erythropoietin / Q000494:pharmacology*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy* / Q000503:physiopathology; D032383:Myocytes, Cardiac / Q000187:drug effects*; D010446:Peptide Fragments / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D010446:Peptide Fragments; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; C585201:glutaminyl-glutamyl-glutaminyl-leucyl-glutamyl-arginyl-alanyl-leucyl-asparagyl-seryl-serine; D004921:Erythropoietin; D045304:Cytochromes c; D020169:Caspases