2. Academic Validation
  3. Ventricular SK2 upregulation following angiotensin II challenge: Modulation by p21-activated kinase-1

Ventricular SK2 upregulation following angiotensin II challenge: Modulation by p21-activated kinase-1

  • J Mol Cell Cardiol. 2022 Mar;164:110-125. doi: 10.1016/j.yjmcc.2021.11.001.
Binbin Yang 1,  Qin Jiang 2,  Shicheng He 2,  Tao Li 3,  Xianhong Ou 3,  Tangting Chen 3,  Xuehui Fan 3,  Feng Jiang 4,  Xiaorong Zeng 3,  Christopher L-H Huang 5,  Ming Lei 6,  Xiaoqiu Tan 7
Affiliations

Affiliations

  • 1 Key Laboratory of Medical Electrophysiology of the Ministry of Education, Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, China; Oral & Maxillofacial Reconstruction and Regeneration Laboratory, The Affiliated Stomatology Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China.
  • 2 Key Laboratory of Medical Electrophysiology of the Ministry of Education, Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, China; Department of Cardiology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China.
  • 3 Key Laboratory of Medical Electrophysiology of the Ministry of Education, Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, China.
  • 4 Department of Cardiology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China.
  • 5 Key Laboratory of Medical Electrophysiology of the Ministry of Education, Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, China; Physiological Laboratory and Department of Biochemistry, University of Cambridge, Cambridge CB2 3EG, UK.
  • 6 Key Laboratory of Medical Electrophysiology of the Ministry of Education, Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, China; Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK. Electronic address: ming.lei@pharm.ox.ac.uk.
  • 7 Key Laboratory of Medical Electrophysiology of the Ministry of Education, Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, China; Department of Cardiology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China. Electronic address: tanxiaoqiu@swmu.edu.cn.
PMID: 34774547 DOI: 10.1016/j.yjmcc.2021.11.001
Abstract

Effects of hypertrophic challenge on small-conductance, CA2+-activated K+(SK2) channel expression were explored in intact murine hearts, isolated ventricular myocytes and neonatal rat cardiomyocytes (NRCMs). An established experimental platform applied angiotensin II (Ang II) challenge in the presence and absence of reduced p21-activated kinase (PAK1) (PAK1cko vs. PAK1f/f, or shRNA-PAK1 interference) expression. SK2 current contributions were detected through their sensitivity to apamin block. Ang II treatment increased such SK2 contributions to optically mapped action potential durations (APD80) and their heterogeneity, and to patch-clamp currents. Such changes were accentuated in PAK1cko compared to PAK1f/f, intact hearts and isolated cardiomyocytes. They paralleled increased histological and echocardiographic hypertrophic indices, reduced cardiac contractility, and increased SK2 protein expression, changes similarly greater with PAK1cko than PAK1f/f. In NRCMs, Ang II challenge replicated such increases in apamin-sensitive SK patch clamp currents as well as in Real-Time PCR and western blot measures of SK2 mRNA and protein expression and cell hypertrophy. Furthermore, the latter were enhanced by shRNA-PAK1 interference and mitigated by the PAK1 agonist FTY720. Increased CaMKII and CREB phosphorylation accompanied these effects. These were rescued by both FTY720 as well as the CaMKII inhibitor KN93, but not its inactive analogue KN92. Such CREB then specifically bound to the KCNN2 promoter sequence in luciferase assays. These findings associate Ang II induced hypertrophy with increased SK2 expression brought about by a CaMKII/CREB signaling convergent with the PAK1 pathway thence upregulating the KCNN2 promoter activity. SK2 may then influence cardiac electrophysiology under conditions of cardiac hypertrophy and failure.

Keywords

Angiotensin II; CREB; CaMKII; Cardiac failure; Cardiac hypertrophy; SK2 channels; p21-activated protein kinase-1.

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