title: Regulation of phosphatase and tensin homolog on chromosome 10 in response to hypoxia.
abstract: Phosphatase and tensin homolog on chromosome 10 (PTEN) is downregulated during hypertrophic and cancerous cell growth, leading to activation of the prosurvival Akt pathway. However, PTEN regulation in cardiac myocytes upon exposure to hypoxia remains unclear. We explored the role of PTEN in response to hypoxia/ischemia in the myocardium. We validated that PTEN is a transcriptional target of activating transcription factor 2 (ATF-2) and is positively regulated via a p38/ATF-2 signaling pathway. Accordingly, hypoxia-induced upregulation of phosphorylation of ATF-2 and PTEN were reversed by a dominant negative mutant p38. Inhibition of PTEN in cardiomyocytes attenuated hypoxia-induced cell death and apoptosis. Cardiac-specific knockout of PTEN resulted in increased phosphorylation of Akt and forkhead box O 1 (forkhead transcription factors), limited infarct size in animals exposed to ischemia-reperfusion injury, and ameliorated deterioration of left ventricular function and remodeling following permanent coronary artery occlusion. In addition, the activation of Bim, FASL, and caspase was coupled with PTEN activation, all of which were attenuated by PTEN inhibition. In conclusion, cardiomyocyte-specific conditional PTEN deletion limited myocardial infarct size in an in vivo model of ischemia-reperfusion injury and attenuated adverse remodeling in a model of chronic permanent coronary artery ligation.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77555, USA.
authors.forename: Jinqiao
authors.initials: J
authors.lastname: Qian
authors.forename: Shukuan
authors.initials: S
authors.lastname: Ling
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Castillo
authors.forename: Bo
authors.initials: B
authors.lastname: Long
authors.forename: Yochai
authors.initials: Y
authors.lastname: Birnbaum
authors.forename: Yumei
authors.initials: Y
authors.lastname: Ye
mesh_terms: D051698:Activating Transcription Factor 2 / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002478:Cells, Cultured; D033481:Chromosomes, Mammalian / Q000235:genetics* / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism* / Q000473:pathology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D023421:Models, Animal; D009203:Myocardial Infarction / Q000473:pathology; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000473:pathology; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000473:pathology; D051059:PTEN Phosphohydrolase / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D051698:Activating Transcription Factor 2; C497106:Atf2 protein, mouse; D048051:p38 Mitogen-Activated Protein Kinases; D051059:PTEN Phosphohydrolase; C487757:Pten protein, mouse