title: Overexpression of M₃ muscarinic receptor is a novel strategy for preventing sudden cardiac death in transgenic mice.
abstract: The present study was designed to investigate the cardiac benefits of M₃ muscarinic receptor (M₃-mAChR) overexpression and whether these effects are related to the regulation of the inward rectifying K⁺ channel by microRNA-1 (miR-1) in a conditional overexpression mouse model. A cardiac-specific M₃-mAChR transgenic mouse model was successfully established for the first time in this study using microinjection, and the overexpression was confirmed by both reverse transcriptase-polymerase chain reaction and Western blot techniques. We demonstrated that M₃-mAChR overexpression dramatically reduced the incidence of arrhythmias and decreased the mortality in a mouse model of myocardial ischemia-reperfusion (I/R). By using whole-cell patch techniques, M₃-mAChR overexpression significantly shortened the action potential duration and restored the membrane repolarization by increasing the inward rectifying K⁺ current. By using Western blot techniques, M₃-mAChR overexpression also rescued the expression of the inward rectifying K⁺ channel subunit Kir2.1 after myocardial I/R injury. This result was accompanied by suppression of upregulation miR-1. We conclude that M₃-mAChR overexpression reduced the incidence of arrhythmias and mortality after myocardial I/R by protecting the myocardium from ischemia in mice. This effect may be mediated by increasing the inward rectifying K⁺ current by downregulation of arrhythmogenic miR-1 expression, which might partially be a novel strategy for antiarrhythmias, leading to sudden cardiac death.
authors.affiliation: Department of Pharmacology, State-Province Key Laboratories of Biomedicine and Pharmaceutics, Harbin, Heilongjiang, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Lihua
authors.initials: L
authors.lastname: Sun
authors.forename: Zhenwei
authors.initials: Z
authors.lastname: Pan
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Bai
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
authors.forename: Jinlong
authors.initials: J
authors.lastname: Zhao
authors.forename: Chaoqian
authors.initials: C
authors.lastname: Xu
authors.forename: Zhi
authors.initials: Z
authors.lastname: Li
authors.forename: Baoxin
authors.initials: B
authors.lastname: Li
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Du
authors.forename: Yanjie
authors.initials: Y
authors.lastname: Lu
authors.forename: Xu
authors.initials: X
authors.lastname: Gao
authors.forename: Baofeng
authors.initials: B
authors.lastname: Yang
mesh_terms: D000157:Aconitine; D000200:Action Potentials; D000818:Animals; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D005786:Gene Expression Regulation; D006352:Heart Ventricles / Q000473:pathology; D015640:Ion Channel Gating; D051379:Mice; D008822:Mice, Transgenic; D035683:MicroRNAs / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000473:pathology; D018995:Myosin Heavy Chains / Q000235:genetics; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D043587:Receptor, Muscarinic M3 / Q000235:genetics / Q000378:metabolism*
chemical_list: D015220:Calcium Channels; D035683:MicroRNAs; C517731:Mirn1 microRNA, mouse; D015221:Potassium Channels; D021122:Protein Subunits; D012333:RNA, Messenger; D043587:Receptor, Muscarinic M3; D018995:Myosin Heavy Chains; D000157:Aconitine