1
|
Cserne Szappanos H, Viola HM, Ito DW, Lim S, Mangala M, Holliday M, Barratt Ross S, Semsarian C, Hill A, Dixon RE, Hool LC. Cytoskeletal disarray increases arrhythmogenic vulnerability during sympathetic stimulation in a model of hypertrophic cardiomyopathy. Sci Rep 2023; 13:11296. [PMID: 37438479 PMCID: PMC10338442 DOI: 10.1038/s41598-023-38296-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 07/06/2023] [Indexed: 07/14/2023] Open
Abstract
Familial hypertrophic cardiomyopathy (FHC) patients are advised to avoid strenuous exercise due to increased risk of arrhythmias. Mice expressing the human FHC-causing mutation R403Q in the myosin heavy chain gene (MYH6) recapitulate the human phenotype, including cytoskeletal disarray and increased arrhythmia susceptibility. Following in vivo administration of isoproterenol, mutant mice exhibited tachyarrhythmias, poor recovery and fatigue. Arrhythmias were attenuated with the β-blocker atenolol and protein kinase A inhibitor PKI. Mutant cardiac myocytes had significantly prolonged action potentials and triggered automaticity due to reduced repolarization reserve and connexin 43 expression. Isoproterenol shortened cycle length, and escalated electrical instability. Surprisingly isoproterenol did not increase CaV1.2 current. We found alterations in CaV1.2-β1 adrenergic receptor colocalization assessed using super-resolution nanoscopy, and increased CaV1.2 phosphorylation in mutant hearts. Our results reveal for the first time that altered ion channel expression, co-localization and β-adrenergic receptor signaling associated with myocyte disarray contribute to electrical instability in the R403Q mutant heart.
Collapse
Affiliation(s)
| | - Helena M Viola
- School of Human Sciences, University of Western Australia, Crawley, WA, Australia
| | - Danica W Ito
- Department of Physiology and Membrane Biology, University of California, Davis, CA, USA
| | - Seakcheng Lim
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, Australia
- Sydney Medical School, University of Sydney, Sydney, Australia
| | - Melissa Mangala
- Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
| | - Mira Holliday
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, Australia
- Sydney Medical School, University of Sydney, Sydney, Australia
| | - Samantha Barratt Ross
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, Australia
- Sydney Medical School, University of Sydney, Sydney, Australia
| | - Christopher Semsarian
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, Australia
- Sydney Medical School, University of Sydney, Sydney, Australia
- Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia
| | - Adam Hill
- Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
| | - Rose E Dixon
- Department of Physiology and Membrane Biology, University of California, Davis, CA, USA
| | - Livia C Hool
- School of Human Sciences, University of Western Australia, Crawley, WA, Australia.
- Victor Chang Cardiac Research Institute, Sydney, NSW, Australia.
| |
Collapse
|