title: Reperfusion-triggered stress protein response in the myocardium is blocked by post-conditioning. Systems biology pathway analysis highlights the key role of the canonical aryl-hydrocarbon receptor pathway.
abstract: OBJECTIVE
  Ischaemic post-conditioning (IPost-Co) exerts cardioprotection by diminishing ischaemia/reperfusion injury. Yet, the mechanisms involved in such protection remain largely unknown. We have investigated the effects of IPost-Co in cardiac cells and in heart performance using molecular, proteomic and functional approaches.
  
  
  RESULTS
  Pigs underwent 1.5 h mid-left anterior descending balloon occlusion and then were sacrificed without reperfusion (ischaemia; n= 7), subjected to 2.5 h of cardiac reperfusion and sacrificed (n= 5); or subjected to IPost-Co before reperfusion and sacrificed 0.5 h (n= 4) and 2.5 h (n= 5) afterwards. A sham-operated group was included (n= 4). Ischaemic and non-ischaemic myocardium was obtained for molecular/histological analysis. Proteomic analysis was performed by two-dimensional electrophoresis followed by matrix-assisted laser desorption/ionization-time-of-flight identification. Potential protein networks involved were identified by bioinformatics and Ingenuity Pathway Analysis (IPA). Cardiac function was assessed by echocardiography. IPost-Co diminished (up to 2.5 h) reperfusion-induced apoptosis of both the intrinsic and extrinsic pathways whereas it did not affect reperfusion-induced Akt/mammalian target of rapamycin (mTOR)/P70S6K activation. Proteomic studies showed that IPost-Co reverted 43% of cardiac cytoplasmic protein changes observed during ischaemia and ischaemia + reperfusion. Systems biology assessment revealed significant changes in the aryl-hydrocarbon receptor (AhR) pathway (cell damage related). Bioinformatic data were confirmed since the expression of HSP90, AhR, ANRT, and β-tubulin (involved in AhR-signalling transduction) were accordingly modified after IPost-Co. IPost-Co rescued 52% of the left ventricle-at-risk compared with reperfusion alone and resulted in a ≈30% relative improvement in left ventricular ejection fraction (P <0.05).
  
  
  CONCLUSIONS
  IPost-Co improves cardiac function post-myocardial infarction and reduces reperfusion-induced cell damage by down-regulation of the AhR-signalling transduction pathway ultimately leading to infarct size reduction.
authors.affiliation: Cardiovascular Research Center, CSIC-ICCC, Hospital de la Santa Creu i Sant Pau and CIBEROBN-Pathophysiology of Obesity and Nutrition, c/Sant Antoni MªClaret 167, 08025 Barcelona, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Vilahur
authors.forename: Judit
authors.initials: J
authors.lastname: Cubedo
authors.forename: Laura
authors.initials: L
authors.lastname: Casani
authors.forename: Teresa
authors.initials: T
authors.lastname: Padro
authors.forename: Manel
authors.initials: M
authors.lastname: Sabate-Tenas
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Badimon
authors.forename: Lina
authors.initials: L
authors.lastname: Badimon
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D003331:Coronary Vessels / Q000473:pathology*; D003856:Deoxyuracil Nucleotides / Q000378:metabolism; D004452:Echocardiography; D006360:Heat-Shock Proteins / Q000502:physiology*; D057775:Ischemic Postconditioning / Q000379:methods*; D009200:Myocardial Contraction / Q000502:physiology; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000517:prevention & control*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D020543:Proteome / Q000378:metabolism; D040901:Proteomics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D011897:Random Allocation; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D034421:Sus scrofa; D049490:Systems Biology; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
chemical_list: D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D053181:Caspase 8; D003856:Deoxyuracil Nucleotides; D006360:Heat-Shock Proteins; D019869:Phosphatidylinositol 3-Kinases; D020543:Proteome; D019253:Proto-Oncogene Proteins c-bcl-2; D018336:Receptors, Aryl Hydrocarbon; D058570:TOR Serine-Threonine Kinases; C089928:2'-deoxy-5-hydroxyuridine triphosphate