title: Autophagy gene fingerprint in human ischemia and reperfusion.
abstract: OBJECTIVE
  Autophagy is an evolutionary conserved adaptive response that is believed to promote cell survival in response to stressful stimuli via recycling of precursors derived from the degradation of endogenous cellular components. The autophagic molecular machinery is controlled by a large family of autophagy-related genes (ATGs) and downstream regulators. We sought to define the autophagy gene fingerprint associated with human ischemia and reperfusion (IR) injury using an intraoperative model developed by Sellke and colleagues.
  
  
  METHODS
  Right atrial appendages, collected from human hearts before and after cardioplegic arrest and after reperfusion, were submitted for polymerase chain reaction (PCR) array, quantitative real-time PCR, and immunoblot analysis for autophagy proteins and their associated upstream regulators.
  
  
  RESULTS
  Perioperative IR significantly upregulated 11 (13.1%) and downregulated 3 (3.6%) of 84 ATGs. Specifically, there were increases in the autophagy machinery components ATG4A, ATG4C, and ATG4D; tumor necrosis factor-related apoptosis-inducing ligand, MAPK8 and BCL2L1; and chaperone-mediated autophagy activity with increased heat shock protein (HSP) A8, HSP90AA1, and a-synuclein. Autophagy activity was confirmed through observations of higher LC3-I levels and an increase in the LC3-II/LC3-I ratio. Autophagy activation coincided with increased AMPK activation and decreased protein levels of the mammalian target of rapamycin, the latter a key negative regulator of autophagy.
  
  
  CONCLUSIONS
  We provide the first human cardiac fingerprint of autophagy gene expression in response to IR. These findings may inform on appropriate cell- and gene-based therapeutic approaches to limit aberrant cardiac injury.
authors.affiliation: Division of Cardiac Surgery, Keenan Research Centre in the Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Krishna K
authors.initials: KK
authors.lastname: Singh
authors.affiliation: Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Bobby
authors.initials: B
authors.lastname: Yanagawa
authors.affiliation: Division of Cardiac Surgery, Keenan Research Centre in the Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Adrian
authors.initials: A
authors.lastname: Quan
authors.affiliation: Division of Cardiac Surgery, Keenan Research Centre in the Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Rixin
authors.initials: R
authors.lastname: Wang
authors.affiliation: Division of Cardiac Surgery, Keenan Research Centre in the Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Ankit
authors.initials: A
authors.lastname: Garg
authors.affiliation: Division of Cardiac Surgery, Keenan Research Centre in the Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Rishad
authors.initials: R
authors.lastname: Khan
authors.affiliation: Division of Cardiac Surgery, Keenan Research Centre in the Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Yi
authors.initials: Y
authors.lastname: Pan
authors.affiliation: Division of Vascular & Endovascular Surgery, Keenan Research Centre in the Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Wheatcroft
authors.affiliation: Division of Cardiac Surgery, Keenan Research Centre in the Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Fina
authors.initials: F
authors.lastname: Lovren
authors.affiliation: Division of Cardiac Surgery, Keenan Research Centre in the Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada; Division of Endocrinology & Metabolism, Keenan Research Centre in the Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Hwee
authors.initials: H
authors.lastname: Teoh
authors.affiliation: Division of Cardiac Surgery, Keenan Research Centre in the Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada. Electronic address: vermasu@smh.ca.
authors.forename: Subodh
authors.initials: S
authors.lastname: Verma
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D000368:Aged; D017209:Apoptosis / Q000235:genetics; D020517:Atrial Appendage / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D001343:Autophagy / Q000235:genetics*; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation; D006324:Heart Arrest, Induced; D006801:Humans; D008297:Male; D008875:Middle Aged; D015428:Myocardial Reperfusion Injury / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D060888:Real-Time Polymerase Chain Reaction; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases