title: Uncoupling protein 3 mediates H₂O₂ preconditioning-afforded cardioprotection through the inhibition of MPTP opening.
abstract: OBJECTIVE
  Uncoupling protein 3 (UCP3), located in the mitochondrial inner membrane, is cardioprotective, but its mechanisms of preserving mitochondrial function during ischaemia/reperfusion (I/R) are not fully understood. This study investigated whether UCP3 mediates/mimics the cardioprotection of H₂O₂ preconditioning (H₂O₂PC) against I/R injury and the downstream pathway that mediates H₂O₂PC- and UCP3-afforded cardioprotection.
  
  
  RESULTS
  H₂O₂PC at 20 µM for 5 min significantly improved post-ischaemic functional recovery and reduced lactate dehydrogenase (LDH) release and infarct size with concurrently up-regulated UCP3 expressions in perfused rat hearts subjected to global no-flow I/R. These protections were blocked by UCP3 knockdown with short hairpin RNA but mimicked by UCP3 overexpression. Consistently, H₂O₂PC-attenuated I/R-induced cytosolic and mitochondrial Ca(2+) overload, Ca(2+) transient suppression, mitochondrial reactive oxygen species burst, and loss of mitochondrial inner membrane potential were reversed by UCP3 knockdown but mimicked by UCP3 overexpression. Moreover, co-immunoprecipitation assay revealed an interaction of UCP3 with the mitochondrial permeability transition pore (mPTP) component, adenine nucleotide translocator (ANT), while the cardioprotection induced by H₂O₂PC- and UCP3 overexpression in mitochondria, cardiac function, and cell survival was abolished by atractyloside, a mPTP opener binding to ANT, and partially inhibited by a PI3K/Akt inhibitor wortmannin. Furthermore, H₂O₂PC up-regulated the phosphorylation of Akt, and glycogen synthase kinase 3β was blocked by UCP3 knockdown but mimicked by UCP3 overexpression.
  
  
  CONCLUSIONS
  UCP3 mediates the cardioprotection of H₂O₂PC against I/R injury by preserving the mitochondrial function through inhibiting mPTP opening via the interaction with ANT and the PI3K/Akt pathway. Our findings reveal novel mechanisms of UCP3 in the cardioprotection.
authors.affiliation: Key Laboratory of Stem Cell Biology and Laboratory of Molecular Cardiology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine (SJTUSM) and Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), 320 Yue Yang Road, Biological Research Building A, Shanghai 200031, China.
authors.forename: Yixiong
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Key Laboratory of Stem Cell Biology and Laboratory of Molecular Cardiology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine (SJTUSM) and Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), 320 Yue Yang Road, Biological Research Building A, Shanghai 200031, China.
authors.forename: Jinlong
authors.initials: J
authors.lastname: Liu
authors.affiliation: Key Laboratory of Stem Cell Biology and Laboratory of Molecular Cardiology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine (SJTUSM) and Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), 320 Yue Yang Road, Biological Research Building A, Shanghai 200031, China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Stem Cell Biology and Laboratory of Molecular Cardiology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine (SJTUSM) and Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), 320 Yue Yang Road, Biological Research Building A, Shanghai 200031, China.
authors.forename: Jinxi
authors.initials: J
authors.lastname: Wang
authors.affiliation: Key Laboratory of Stem Cell Biology and Laboratory of Molecular Cardiology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine (SJTUSM) and Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), 320 Yue Yang Road, Biological Research Building A, Shanghai 200031, China.
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Key Laboratory of Stem Cell Biology and Laboratory of Molecular Cardiology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine (SJTUSM) and Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), 320 Yue Yang Road, Biological Research Building A, Shanghai 200031, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Gu
authors.affiliation: Key Laboratory of Stem Cell Biology and Laboratory of Molecular Cardiology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine (SJTUSM) and Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), 320 Yue Yang Road, Biological Research Building A, Shanghai 200031, China.
authors.forename: Jiliang
authors.initials: J
authors.lastname: Tan
authors.affiliation: Key Laboratory of Stem Cell Biology and Laboratory of Molecular Cardiology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine (SJTUSM) and Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), 320 Yue Yang Road, Biological Research Building A, Shanghai 200031, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Jing
authors.affiliation: Key Laboratory of Stem Cell Biology and Laboratory of Molecular Cardiology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine (SJTUSM) and Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), 320 Yue Yang Road, Biological Research Building A, Shanghai 200031, China htyang@sibs.ac.cn.
authors.forename: Huangtian
authors.initials: H
authors.lastname: Yang
mesh_terms: D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / Q000378:metabolism*; D000818:Animals; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007473:Ion Channels / Q000378:metabolism*; D019194:Ischemic Preconditioning; D008297:Male; D008929:Mitochondria, Heart / Q000187:drug effects* / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000187:drug effects*; D000083162:Mitochondrial Permeability Transition Pore; D024101:Mitochondrial Proteins / Q000378:metabolism*; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D000071247:Uncoupling Protein 3
chemical_list: D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D006861:Hydrogen Peroxide; D007473:Ion Channels; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D024101:Mitochondrial Proteins; D019869:Phosphatidylinositol 3-Kinases; D000071247:Uncoupling Protein 3; C000604394:Ucp3 protein, rat
keywords: H2O2 preconditioning; Hearts; Ischaemia/reperfusion; MPTP; Mitochondria; Uncoupling protein 3