title: Cardioprotective 3',4'-dihydroxyflavonol attenuation of JNK and p38(MAPK) signalling involves CaMKII inhibition.
abstract: DiOHF (3',4'-dihydroxyflavonol) is cardioprotective against I/R (ischaemia/reperfusion) injury. The biological activities of flavonols are associated with kinase modulation to alter cell signalling. We thus investigated the effects of DiOHF on the activation of MAPKs (mitogen-activated protein kinases) that regulate the cardiac stress response. In an ovine model of I/R, JNK (c-Jun N-terminal kinase), p38(MAPK), ERK (extracellular-signal-regulated kinase) and Akt were activated, and NP202, a pro-drug of DiOHF, reduced infarct size and inhibited JNK and p38(MAPK) activation, whereas ERK and Akt phosphorylation were unaltered. Similarly, in cultured myoblasts, DiOHF pre-treatment preserved viability and inhibited activation of JNK and p38(MAPK), but not ERK in response to acute oxidative and chemotoxic stress. Furthermore, DiOHF prevented stress-activation of the direct upstream regulators MKK4/7 (MAPK kinase 4/7) and MKK3/6 respectively. We utilized small-molecule affinity purification and identified CaMKII (Ca(2+)/calmodulin-dependent protein kinase II) as a kinase targeted by DiOHF and demonstrated potent CaMKII inhibition by DiOHF in vitro. Moreover, the specific inhibition of CaMKII with KN-93, but not KN-92, prevented oxidative stress-induced activation of JNK and p38(MAPK). The present study indicates DiOHF inhibition of CaMKII and attenuation of MKK3/6→p38(MAPK) and MKK4/7→JNK signalling as a requirement for the protective effects of DiOHF against stress stimuli and myocardial I/R injury.
authors.affiliation: *Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, VIC 3010, Australia.
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Lim
authors.forename: Colleen J
authors.initials: CJ
authors.lastname: Thomas
authors.forename: Lokugan S
authors.initials: LS
authors.lastname: Silva
authors.forename: Yvonne Y
authors.initials: YY
authors.lastname: Yeap
authors.forename: Suwan
authors.initials: S
authors.lastname: Yap
authors.forename: James R
authors.initials: JR
authors.lastname: Bell
authors.forename: Lea M D
authors.initials: LM
authors.lastname: Delbridge
authors.forename: Marie A
authors.initials: MA
authors.lastname: Bogoyevitch
authors.forename: Owen L
authors.initials: OL
authors.lastname: Woodman
authors.forename: Spencer J
authors.initials: SJ
authors.lastname: Williams
authors.forename: Clive N
authors.initials: CN
authors.lastname: May
authors.forename: Dominic C H
authors.initials: DC
authors.lastname: Ng
mesh_terms: D000818:Animals; D018053:Arsenites / Q000494:pharmacology; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002316:Cardiotonic Agents / Q000494:pharmacology*; D002460:Cell Line; D044948:Flavonols / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D048670:MAP Kinase Kinase 4 / Q000378:metabolism; D020935:MAP Kinase Signaling System; D051379:Mice; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D051381:Rats; D034561:Sheep, Domestic; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D018053:Arsenites; D002316:Cardiotonic Agents; D044948:Flavonols; D016877:Oxidants; D006861:Hydrogen Peroxide; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; C015001:arsenite; C529890:3',4'-dihydroxyflavonol