title: Cdk1, PKCδ and calcineurin-mediated Drp1 pathway contributes to mitochondrial fission-induced cardiomyocyte death.
abstract: Myocardial ischemia-reperfusion (I/R) injury is one of the leading causes of death and disability worldwide. Mitochondrial fission has been shown to be involved in cardiomyocyte death. However, molecular machinery involved in mitochondrial fission during I/R injury has not yet been completely understood. In this study we aimed to investigate molecular mechanisms of controlling activation of dynamin-related protein 1 (Drp1, a key protein in mitochondrial fission) during anoxia-reoxygenation (A/R) injury of HL1 cardiomyocytes. A/R injury induced cardiomyocyte death accompanied by the increases of mitochondrial fission, reactive oxygen species (ROS) production and activated Drp1 (pSer616 Drp1), and decrease of inactivated Drp1 (pSer637 Drp1) while mitochondrial fusion protein levels were not significantly changed. Blocking Drp1 activity with mitochondrial division inhibitor mdivi1 attenuated cell death, mitochondrial fission, and Drp1 activation after A/R. Trolox, a ROS scavenger, decreased pSer616 Drp1 level and mitochondrial fission after A/R. Immunoprecipitation assay further indicates that cyclin dependent kinase 1 (Cdk1) and protein kinase C isoform delta (PKCδ) bind Drp1, thus increasing mitochondrial fission. Inhibiting Cdk1 and PKCδ attenuated the increases in pSer616 Drp1, mitochondrial fission, and cardiomyocyte death. FK506, a calcineurin inhibitor, blocked the decrease in expression of inactivated pSer637 Drp1 and mitochondrial fission. Our findings reveal the following novel molecular mechanisms controlling mitochondrial fission during A/R injury of cardiomyocytes: (1) ROS are upstream initiators of mitochondrial fission; and (2) the increased mitochondrial fission is resulted from both increased activation and decreased inactivation of Drp1 through Cdk1, PKCδ, and calcineurin-mediated pathways, respectively.
authors.affiliation: Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States.
authors.forename: Ivan
authors.initials: I
authors.lastname: Zaja
authors.affiliation: Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States. Electronic address: xibai@mcw.edu.
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Bai
authors.affiliation: Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States.
authors.forename: Chika
authors.initials: C
authors.lastname: Kikuchi
authors.affiliation: Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States.
authors.forename: Svjetlana
authors.initials: S
authors.lastname: Dosenovic
authors.affiliation: Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States.
authors.forename: Yasheng
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States.
authors.forename: Scott G
authors.initials: SG
authors.lastname: Canfield
authors.affiliation: Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States; Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States.
authors.forename: Zeljko J
authors.initials: ZJ
authors.lastname: Bosnjak
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D019703:Calcineurin / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D034281:Dynamins / Q000378:metabolism*; D051379:Mice; D063154:Mitochondrial Dynamics / Q000502:physiology*; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism*; D051745:Protein Kinase C-delta / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
chemical_list: D017382:Reactive Oxygen Species; C497259:Prkcd protein, mouse; D051745:Protein Kinase C-delta; D016203:CDC2 Protein Kinase; D019703:Calcineurin; C486391:Dnm1l protein, mouse; D034281:Dynamins
keywords: Cardiomyocyte; Ischemia–reperfusion injury; Mitochondrial dynamics; Reactive oxygen species