title: Glutamine protects cardiomyocytes from hypoxia/reoxygenation injury under high glucose conditions through inhibition of the transforming growth factor-β1-Smad3 pathway.
abstract: Activation of transforming growth factor-β1 (TGF-β1)-Smad3 pathway aggravates myocardial ischemia/reperfusion injury (IRI). We previously showed that glutamine (Gln) protects cardiomyocytes from hypoxia/reoxygenation (H/R) injury under high glucose (HG) conditions. The aim of this study was to investigate whether Gln exerts its protective effect in H/R via inhibiting TGF-β1-Smad3 pathway. In vitro, H9c2 rat cardiomyocytes were treated with Gln with HG (33 mM) and/or H/R. We also performed in vivo experiments in which we treated normal and diabetic rats with Gln or solvent control following IRI. We assessed protein levels of TGF-β1, total Smad3, phosphorylated (p)-Smad3 and cleaved caspase-3 in H9c2 cells and rat myocardium by Western blotting. H9c2 cells treated with HG + H/R exhibited high apoptosis rates, as well as a highly activated TGF-β1-Smad3 pathway. TGF-β1 receptor inhibitor (SB431542) or Smad3 inhibitor (SIS3) reduced HG + H/R induced apoptosis. Similarly, Gln supplementation alleviated apoptosis and decreased p-Smad3 levels. However, Gln's protective effect was significantly weakened by TGF-β1. Diabetic rats treated with Gln had improved hemodynamics, smaller infarct size after IRI, and a significant decrease in TGF-β1-Smad3 pathway activation. We conclude that Gln inhibits HG + H/R induced activation of the TGF-β1-Smad3 pathway and decreases cell apoptosis in cardiomyocytes.
authors.affiliation: Animal Experimental Centre, Beijing Key Laboratory of Pre-clinical Research and Evaluation for Cardiovascular Implant Materials, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Centre for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Animal Experimental Centre, Beijing Key Laboratory of Pre-clinical Research and Evaluation for Cardiovascular Implant Materials, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Centre for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
authors.forename: Yong-Chun
authors.initials: YC
authors.lastname: Cui
authors.affiliation: Animal Experimental Centre, Beijing Key Laboratory of Pre-clinical Research and Evaluation for Cardiovascular Implant Materials, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Centre for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Li
authors.affiliation: Animal Experimental Centre, Beijing Key Laboratory of Pre-clinical Research and Evaluation for Cardiovascular Implant Materials, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Centre for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
authors.forename: Bai-Qing
authors.initials: BQ
authors.lastname: Yang
authors.affiliation: Animal Experimental Centre, Beijing Key Laboratory of Pre-clinical Research and Evaluation for Cardiovascular Implant Materials, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Centre for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
authors.forename: Xiao-Peng
authors.initials: XP
authors.lastname: Liu
authors.affiliation: Animal Experimental Centre, Beijing Key Laboratory of Pre-clinical Research and Evaluation for Cardiovascular Implant Materials, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Centre for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Animal Experimental Centre, Beijing Key Laboratory of Pre-clinical Research and Evaluation for Cardiovascular Implant Materials, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Centre for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.affiliation: Animal Experimental Centre, Beijing Key Laboratory of Pre-clinical Research and Evaluation for Cardiovascular Implant Materials, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Centre for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
authors.forename: Ai-Li
authors.initials: AL
authors.lastname: Wu
authors.affiliation: Animal Experimental Centre, Beijing Key Laboratory of Pre-clinical Research and Evaluation for Cardiovascular Implant Materials, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Centre for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China. Electronic address: tangyue@fuwaihospital.org.
authors.forename: Yue
authors.initials: Y
authors.lastname: Tang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D015687:Cell Hypoxia / Q000187:drug effects; D002460:Cell Line; D005947:Glucose / Q000494:pharmacology*; D005973:Glutamine / Q000494:pharmacology*; D015428:Myocardial Reperfusion Injury / Q000378:metabolism* / Q000473:pathology; D032383:Myocytes, Cardiac / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects*; D051900:Smad3 Protein / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
chemical_list: D051900:Smad3 Protein; C497787:Smad3 protein, rat; C508962:Tgfb1 protein, rat; D053773:Transforming Growth Factor beta1; D005973:Glutamine; C505410:Casp3 protein, rat; D053148:Caspase 3; D005947:Glucose
keywords: Apoptosis; Glutamine; H9c2 cells; High glucose; Hypoxia/ reoxygenation; TGF-β1-Smad3 pathway