title: Type 10 adenylyl cyclase mediates mitochondrial Bax translocation and apoptosis of adult rat cardiomyocytes under simulated ischaemia/reperfusion.
abstract: OBJECTIVE
  Apoptosis of cardiomyocytes significantly contributes to the development of post-ischaemic cardiomyopathy. Although mitochondria have been suggested to play a crucial role in this process, the precise mechanisms controlling the mitochondria-dependent apoptosis in cardiomyocytes under ischaemia/reperfusion are still poorly understood. Here we aimed to analyse the role of the soluble adenylyl cyclase (sAC).
  
  
  RESULTS
  Adult rat cardiomyocytes were subjected to simulated in vitro ischaemia (SI) consisting of glucose-free anoxia at pH 6.4. Apoptosis was detected by DNA laddering, chromatin condensation, and caspases cleavage. SI led to the translocation of sAC to the mitochondria and mitochondrial depolarization followed by cytochrome c release, caspase-9/-3 cleavage and apoptosis during simulated reperfusion (SR). Pharmacological inhibition of sAC during SI, but not during SR, significantly reduced the SI/SR-induced mitochondrial injury and apoptosis. Similarly, sAC knock-down mediated by an adenovirus coding for shRNA targeting sAC prevented the activation of the mitochondrial pathway of apoptosis. Analysis of the link between sAC and apoptosis revealed a sAC and protein kinase A-dependent Bax phosphorylation at Thr(167) and its translocation to mitochondria during SI, which subsequently caused mitochondrial oxygen radical formation followed by cytochrome c release and caspase-9 cleavage during SR.
  
  
  CONCLUSIONS
  These results suggest a key role of sAC in SI-induced mitochondrial Bax translocation and activation of the mitochondrial pathway of apoptosis in adult cardiomyocytes.
authors: Department of Clinical Pharmacology,  Ruhr-University Bochum, Universitätsstrasse 150, Bochum 44801,  Germany.
authors: Avinash
authors: A
authors: Appukuttan
authors: Sascha A
authors: SA
authors: Kasseckert
authors: Mustafa
authors: M
authors: Micoogullari
authors: Jan-Paul
authors: JP
authors: Flacke
authors: Sanjeev
authors: S
authors: Kumar
authors: Alexandra
authors: A
authors: Woste
authors: Yaser
authors: Y
authors: Abdallah
authors: Lutz
authors: L
authors: Pott
authors: H Peter
authors: HP
authors: Reusch
authors: Yury
authors: Y
authors: Ladilov
mesh_terms: D000262:Adenylyl Cyclases / Q000502:physiology*; D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000502:physiology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D008297:Male; D008929:Mitochondria, Heart / Q000378:metabolism*; D015425:Myocardial Reperfusion; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D021381:Protein Transport; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism*
chemical_list: C494828:Bax protein, rat; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D000262:Adenylyl Cyclases