title: Reduced expression of mitochondrial electron transport chain proteins from hibernating hearts relative to ischemic preconditioned hearts in the second window of protection.
abstract: Although protection against necrosis has been observed in both hibernating (HIB) and ischemic preconditioned hearts in the second window of protection (SWOP), a comparison of the mitochondrial proteome between the two entities has not been previously performed. Anesthetized swine underwent instrumentation with a fixed constrictor around the LAD artery and were followed for 12 weeks (HIB; N=7). A second group of anesthetized swine underwent ischemic preconditioning by inflating a balloon within the LAD artery 10 times for 2 min, each separated by 2 min reperfusion and were sacrificed 24h later (SWOP; N=7). Myocardial blood flow and high-energy nucleotides were obtained in the LAD region and normalized to remote regions. Post-sacrifice, protein content as measured with iTRAQ was compared in isolated mitochondria from the LAD area of a Sham heart. Basal regional blood flow in the LAD region when normalized to the remote region was 0.86±0.04 in HIB and 1.02±0.02 in SWOP tissue (P<0.05). Despite reduced regional blood flows in HIB hearts, ATP content in the LAD region, when normalized to the remote region was similar in HIB versus SWOP (1.06±0.06 and 1.02±0.05 respectively; NS) as was the transmural phosphocreatine (PCr) to ATP ratio (2.1±0.2 and 2.2±0.2 respectively; NS). Using iTRAQ, 64 common proteins were identified in HIB and SWOP hearts. Compared with SWOP, the relative abundance of mitochondrial proteins involved with electron transport chain (ETC) were reduced in HIB including NADH dehydrogenase, Cytochrome c reductase and oxidase, ATP synthase, and nicotinamide nucleotide transhydrogenase. Within chronically HIB heart tissue with reduced blood flow, the relative abundance of mitochondrial ETC proteins is decreased when compared with SWOP tissue. These data support the concept that HIB heart tissue subjected to chronically reduced blood flow is associated with a down-regulation in the expression of key mitochondrial proteins involved in electron transport.
authors.affiliation: Cardiology & Cardiothoracic Surgery Sections, VA Medical Center & University of Minnesota, Minneapolis, MN 55417, USA.
authors.forename: Jesús A
authors.initials: JA
authors.lastname: Cabrera
authors.forename: Tammy A
authors.initials: TA
authors.lastname: Butterick
authors.forename: Eric K
authors.initials: EK
authors.lastname: Long
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Ziemba
authors.forename: Lorraine B
authors.initials: LB
authors.lastname: Anderson
authors.forename: Cayla M
authors.initials: CM
authors.lastname: Duffy
authors.forename: Willem
authors.initials: W
authors.lastname: Sluiter
authors.forename: Dirk J
authors.initials: DJ
authors.lastname: Duncker
authors.forename: Jianyi
authors.initials: J
authors.lastname: Zhang
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Chen
authors.forename: Herbert B
authors.initials: HB
authors.lastname: Ward
authors.forename: Rosemary F
authors.initials: RF
authors.lastname: Kelly
authors.forename: Edward O
authors.initials: EO
authors.lastname: McFalls
mesh_terms: D000818:Animals; D003326:Coronary Circulation; D045222:Electron Transport Chain Complex Proteins / Q000096:biosynthesis*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D008929:Mitochondria, Heart / Q000201:enzymology* / Q000473:pathology; D024101:Mitochondrial Proteins / Q000096:biosynthesis*; D009124:Muscle Proteins / Q000096:biosynthesis*; D009206:Myocardium / Q000201:enzymology* / Q000473:pathology; D009336:Necrosis / Q000201:enzymology / Q000235:genetics; D013552:Swine
chemical_list: D045222:Electron Transport Chain Complex Proteins; D024101:Mitochondrial Proteins; D009124:Muscle Proteins