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Jung E, Capel R, Jiang C, Venturi E, Neagu G, Pearcey S, Zhou Y, Zhang Y, Lei M. Cardiac deficiency of P21-activated kinase 1 promotes atrial arrhythmogenesis in mice following adrenergic challenge. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220168. [PMID: 37122217 PMCID: PMC10150202 DOI: 10.1098/rstb.2022.0168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 11/24/2022] [Indexed: 05/02/2023] Open
Abstract
P21-activated kinase 1 (Pak1) signalling plays a vital and overall protective role in the heart. However, the phenotypes of Pak1 deficiency in the cardiac atria have not been well explored. In this study, Pak1 cardiac-conditional knock-out (cKO) mice were studied under baseline and adrenergic challenge conditions. Pak1 cKO mice show atrial arrhythmias including atrial fibrillation (AF) in vivo, detected during anaesthetized electrocardiography without evidence of interstitial fibrosis upon Masson's trichrome staining. Optical mapping of left atrial preparations from Pak1 cKO mice revealed a higher incidence of Ca2+ and action potential alternans under isoprenaline challenge and differences in baseline action potential and calcium transient characteristics. Type-2 ryanodine receptor (RyR2) channels from Pak1 cKO hearts had a higher open probability than those from wild-type. Reverse transcription-quantitative polymerase chain reaction and Western blotting indicated that pCamkIIδ and RyR2 are highly phosphorylated at baseline in the atria of Pak1 cKO mice, while the expression of Slc8a2 and Slc8a3 as a Na+-Ca2+ exchanger, controlling the influx of Ca2+ from outside of the cell and efflux of Na+ from the cytoplasm, are augmented. Chromatin immunoprecipitation study showed that pCreb1 interacts with Slc8a2 and Slc8a3. Our study thus demonstrates that deficiency of Pak1 promotes atrial arrhythmogenesis under adrenergic stress, probably through post-translational and transcriptional modifications of key molecules that are critical to Ca2+ homeostasis. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
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Affiliation(s)
- Eunjeong Jung
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Rebecca Capel
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Congshan Jiang
- National Regional Children's Medical Center (Northwest); Key Laboratory of Precision Medicine to Pediatric Diseases of Shaanxi Province; Xi'an Key Laboratory of Children's Health and Diseases, Shaanxi Institute for Pediatric Diseases; Xi'an Children's Hospital, Affiliated Children's Hospital of Xi'an Jiaotong University. No. 69, Xijuyuan Lane, Xi'an 710003, People's Republic of China
| | - Elisa Venturi
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Georgiana Neagu
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Sarah Pearcey
- Paediatric Intensive Care, Addenbrooke's Hospital, Cambridge CB2 1QY, UK
| | - Yafei Zhou
- National Regional Children's Medical Center (Northwest); Key Laboratory of Precision Medicine to Pediatric Diseases of Shaanxi Province; Xi'an Key Laboratory of Children's Health and Diseases, Shaanxi Institute for Pediatric Diseases; Xi'an Children's Hospital, Affiliated Children's Hospital of Xi'an Jiaotong University. No. 69, Xijuyuan Lane, Xi'an 710003, People's Republic of China
- 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, People's Republic of China
| | - Yanmin Zhang
- National Regional Children's Medical Center (Northwest); Key Laboratory of Precision Medicine to Pediatric Diseases of Shaanxi Province; Xi'an Key Laboratory of Children's Health and Diseases, Shaanxi Institute for Pediatric Diseases; Xi'an Children's Hospital, Affiliated Children's Hospital of Xi'an Jiaotong University. No. 69, Xijuyuan Lane, Xi'an 710003, People's Republic of China
- Institute of Cardiovascular Sciences, Faculty of Medicine and Human Science, University of Manchester, Manchester, M13, 9GB UK
| | - Ming Lei
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
- 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, People's Republic of China
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Pereira CH, Bare DJ, Rosas PC, Dias FAL, Banach K. The role of P21-activated kinase (Pak1) in sinus node function. J Mol Cell Cardiol 2023; 179:90-101. [PMID: 37086972 PMCID: PMC10294268 DOI: 10.1016/j.yjmcc.2023.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 04/11/2023] [Accepted: 04/11/2023] [Indexed: 04/24/2023]
Abstract
Sinoatrial node (SAN) dysfunction (SND) and atrial arrhythmia frequently occur simultaneously with a hazard ratio of 4.2 for new onset atrial fibrillation (AF) in SND patients. In the atrial muscle attenuated activity of p21-activated kinase 1 (Pak1) increases the risk for AF by enhancing NADPH oxidase 2 dependent production of reactive oxygen species (ROS). However, the role of Pak1 dependent ROS regulation in SAN function has not yet been determined. We hypothesize that Pak1 activity maintains SAN activity by regulating the expression of the hyperpolarization activated cyclic nucleotide gated cation channel (HCN). To determine Pak1 dependent changes in heart rate (HR) regulation we quantified the intrinsic sinus rhythm in wild type (WT) and Pak1 deficient (Pak1-/-) mice of both sexes in vivo and in isolated Langendorff perfused hearts. Pak1-/- hearts displayed an attenuated HR in vivo after autonomic blockage and in isolated hearts. The contribution of the Ca2+ clock to pacemaker activity remained unchanged, but Ivabradine (3 μM), a blocker of HCN channels that are a membrane clock component, eliminated the differences in SAN activity between WT and Pak1-/- hearts. Reduced HCN4 expression was confirmed in Pak1-/- right atria. The reduced HCN activity in Pak1-/- could be rescued by class II HDAC inhibition (LMK235), ROS scavenging (TEMPOL) or attenuation of Extracellular Signal-Regulated Kinase (ERK) 1/2 activity (SCH772984). No sex specific differences in Pak1 dependent SAN regulation were determined. Our results establish Pak1 as a class II HDAC regulator and a potential therapeutic target to attenuate SAN bradycardia and AF susceptibility.
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Affiliation(s)
- Carlos H Pereira
- Dept. of Internal Medicine/Cardiology, Rush University Medical Center, 1750 W. Harrison St., Chicago, IL 60612, USA; Biological Science Center, Department of Physiology, Av. Cel Francisco H. dos Santos 100, 19031 Centro Politécnico-Curitiba, Brazil.
| | - Dan J Bare
- Dept. of Physiology & Biophysics, The Ohio State University, 5018 Graves Hall, 333 W.10th Ave., Columbus, OH 4321, USA.
| | - Paola C Rosas
- Dept. of Pharmacy Practice, College of Pharmacy, 833 S Wood St., Chicago, IL 60612, USA.
| | - Fernando A L Dias
- Biological Science Center, Department of Physiology, Av. Cel Francisco H. dos Santos 100, 19031 Centro Politécnico-Curitiba, Brazil.
| | - Kathrin Banach
- Dept. of Internal Medicine/Cardiology, Rush University Medical Center, 1750 W. Harrison St., Chicago, IL 60612, USA.
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Dittloff KT, Spanghero E, Solís C, Banach K, Russell B. Transthyretin deposition alters cardiomyocyte sarcomeric architecture, calcium transients, and contractile force. Physiol Rep 2022; 10:e15207. [PMID: 35262277 PMCID: PMC8906053 DOI: 10.14814/phy2.15207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/20/2022] [Accepted: 02/06/2022] [Indexed: 06/14/2023] Open
Abstract
Age-related wild-type transthyretin amyloidosis (wtATTR) is characterized by systemic deposition of amyloidogenic fibrils of misfolded transthyretin (TTR) in the connective tissue of many organs. In the heart, this leads to age-related heart failure with preserved ejection fraction (HFpEF). The hypothesis tested is that TTR deposited in vitro disrupts cardiac myocyte cell-to-cell and cell-to-matrix adhesion complexes, resulting in altered calcium handling, force generation, and sarcomeric disorganization. Human iPSC-derived cardiomyocytes and neonatal rat ventricular myocytes (NRVMs), when grown on TTR-coated polymeric substrata mimicking the stiffness of the healthy human myocardium (10 kPa), had decreased contraction and relaxation velocities as well as decreased force production measured using traction force microscopy. Both NRVMs and adult mouse atrial cardiomyocytes had altered calcium kinetics with prolonged transients when cultured on TTR fibril-coated substrates. Furthermore, NRVMs grown on stiff (~GPa), flat or microgrooved substrates coated with TTR fibrils exhibited significantly decreased intercellular electrical coupling as shown by FRAP dynamics of cells loaded with the gap junction-permeable dye calcein-AM, along with decreased gap junction content as determined by quantitative connexin 43 staining. Significant sarcomeric disorganization and loss of sarcomere content, with increased ubiquitin localization to the sarcomere, were seen in NRVMs on various TTR fibril-coated substrata. TTR presence decreased intercellular mechanical junctions as evidenced by quantitative immunofluorescence staining of N-cadherin and vinculin. Current therapies for wtATTR are cost-prohibitive and only slow the disease progression; therefore, better understanding of cardiomyocyte maladaptation induced by TTR amyloid may identify novel therapeutic targets.
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Affiliation(s)
- Kyle T. Dittloff
- Department of Physiology and BiophysicsUniversity of Illinois at ChicagoChicagoIllinoisUSA
| | - Emanuele Spanghero
- Department of Biomedical EngineeringUniversity of Illinois at ChicagoChicagoIllinoisUSA
| | - Christopher Solís
- Department of Physiology and BiophysicsUniversity of Illinois at ChicagoChicagoIllinoisUSA
| | - Kathrin Banach
- Department of Internal Medicine/CardiologyRush University Medical CenterChicagoIllinoisUSA
| | - Brenda Russell
- Department of Physiology and BiophysicsUniversity of Illinois at ChicagoChicagoIllinoisUSA
- Department of Biomedical EngineeringUniversity of Illinois at ChicagoChicagoIllinoisUSA
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Abstract
BACKGROUND Atrial fibrillation (AF) is initiated through arrhythmic atrial excitation from outside the sinus node or remodeling of atrial tissue that allows reentry of excitation. Angiotensin II (AngII) has been implicated in the initiation and maintenance of AF through changes in Ca2+ handling and production of reactive oxygen species (ROS). OBJECTIVE We aimed to determine the role of p21-activated kinase 1 (Pak1), a downstream target in the AngII signaling cascade, in atrial electrophysiology and arrhythmia. METHODS Wild-type and Pak1-/- mice were used to determine atrial function in vivo on the organ and cellular level by quantification of electrophysiological and Ca2+ handling properties. RESULTS We demonstrate that reduced Pak1 activity increases the inducibility of atrial arrhythmia in vivo and in vitro. On the cellular level, Pak1-/- atrial myocytes (AMs) exhibit increased basal and AngII (1 μM)-induced ROS production, sensitivity to the NADPH oxidase-2 (NOX2) inhibitors gp91ds-tat and apocynin (1 μM), and enhanced membrane translocation of Ras-related C3 substrate 1 (Rac1) that is part of the multimolecular NOX2 complex. Upon stimulation with AngII, Pak1-/- AMs exhibit an exaggerated increase in the intracellular Calcium concentration ([Ca2+]i) and arrhythmic events that were sensitive to sodium-calcium exchanger (NCX) inhibitors (KB-R7943 and SEA0400; 1 μM) and suppressed in AMs from NOX2-deficient (gp91phox-/-) mice. Pak1 stimulation (FTY720; 200 nM) in wild-type AMs and AMs from a canine model of ventricular tachypacing-induced AF prevented AngII-induced arrhythmic Ca2+ overload by attenuating NCX activity in a NOX2-dependent manner. CONCLUSION The experimental results support that Pak1 stimulation can attenuate NCX-dependent Ca2+ overload and prevent triggered arrhythmic activity by suppressing NOX2-dependent ROS production.
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Wang Y, Wang S, Lei M, Boyett M, Tsui H, Liu W, Wang X. The p21-activated kinase 1 (Pak1) signalling pathway in cardiac disease: from mechanistic study to therapeutic exploration. Br J Pharmacol 2017; 175:1362-1374. [PMID: 28574147 DOI: 10.1111/bph.13872] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/12/2017] [Accepted: 05/17/2017] [Indexed: 01/01/2023] Open
Abstract
p21-activated kinase 1 (Pak1) is a member of the highly conserved family of serine/threonine protein kinases regulated by Ras-related small G-proteins, Cdc42/Rac1. It has been previously demonstrated to be involved in cardiac protection. Based on recent studies, this review provides an overview of the role of Pak1 in cardiac diseases including disrupted Ca2+ homoeostasis-related cardiac arrhythmias, adrenergic stress- and pressure overload-induced hypertrophy, and ischaemia/reperfusion injury. These findings demonstrate the important role of Pak1 mediated through the phosphorylation and transcriptional modification of hypertrophy and/or arrhythmia-related genes. This review also discusses the anti-arrhythmic and anti-hypertrophic, protective function of Pak1 and the beneficial effects of fingolimod (an FDA-approved sphingolipid drug), a Pak1 activator, and its ability to prevent arrhythmias and cardiac hypertrophy. These findings also highlight the therapeutic potential of Pak1 signalling in the treatment and prevention of cardiac diseases. LINKED ARTICLES This article is part of a themed section on Spotlight on Small Molecules in Cardiovascular Diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.8/issuetoc.
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Affiliation(s)
- Yanwen Wang
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Shunyao Wang
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Ming Lei
- Department of Pharmacology, The University of Oxford, Oxford, UK
| | - Mark Boyett
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Hoyee Tsui
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Wei Liu
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Xin Wang
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
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6
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Seidel T, Navankasattusas S, Ahmad A, Diakos NA, Xu WD, Tristani-Firouzi M, Bonios MJ, Taleb I, Li DY, Selzman CH, Drakos SG, Sachse FB. Sheet-Like Remodeling of the Transverse Tubular System in Human Heart Failure Impairs Excitation-Contraction Coupling and Functional Recovery by Mechanical Unloading. Circulation 2017; 135:1632-1645. [PMID: 28073805 PMCID: PMC5404964 DOI: 10.1161/circulationaha.116.024470] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 12/14/2016] [Indexed: 01/02/2023]
Abstract
BACKGROUND Cardiac recovery in response to mechanical unloading by left ventricular assist devices (LVADs) has been demonstrated in subgroups of patients with chronic heart failure (HF). Hallmarks of HF are depletion and disorganization of the transverse tubular system (t-system) in cardiomyocytes. Here, we investigated remodeling of the t-system in human end-stage HF and its role in cardiac recovery. METHODS Left ventricular biopsies were obtained from 5 donors and 26 patients with chronic HF undergoing implantation of LVADs. Three-dimensional confocal microscopy and computational image analysis were applied to assess t-system structure, density, and distance of ryanodine receptor clusters to the sarcolemma, including the t-system. Recovery of cardiac function in response to mechanical unloading was assessed by echocardiography during turndown of the LVAD. RESULTS The majority of HF myocytes showed remarkable t-system remodeling, particularly sheet-like invaginations of the sarcolemma. Circularity of t-system components was decreased in HF versus controls (0.37±0.01 versus 0.46±0.02; P<0.01), and the volume/length ratio was increased in HF (0.36±0.01 versus 0.25±0.02 µm2; P<0.0001). T-system density was reduced in HF, leading to increased ryanodine receptor-sarcolemma distances (0.96±0.05 versus 0.64±0.1 µm; P<0.01). Low ryanodine receptor-sarcolemma distances at the time of LVAD implantation predicted high post-LVAD left ventricular ejection fractions (P<0.01) and ejection fraction increases during unloading (P<0.01). Ejection fraction in patients with pre-LVAD ryanodine receptor-sarcolemma distances >1 µm did not improve after mechanical unloading. In addition, calcium transients were recorded in field-stimulated isolated human cardiomyocytes and analyzed with respect to local t-system density. Calcium release in HF myocytes was restricted to regions proximal to the sarcolemma. Local calcium upstroke was delayed (23.9±4.9 versus 10.3±1.7 milliseconds; P<0.05) and more asynchronous (18.1±1.5 versus 8.9±2.2 milliseconds; P<0.01) in HF cells with low t-system density versus cells with high t-system density. CONCLUSIONS The t-system in end-stage human HF presents a characteristic novel phenotype consisting of sheet-like invaginations of the sarcolemma. Our results suggest that the remodeled t-system impairs excitation-contraction coupling and functional recovery during chronic LVAD unloading. An intact t-system at the time of LVAD implantation may constitute a precondition and predictor for functional cardiac recovery after mechanical unloading.
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Affiliation(s)
- Thomas Seidel
- From Nora Eccles Harrison Cardiovascular Research and Training Institute (T.S., A.A., M.T.-F., S.G.D., F.B.S.), Molecular Medicine Program (S.N., N.A.D., D.Y.L., C.H.S.), Department of Bioengineering (A.A., F.B.S.), Division of Cardiovascular Medicine (W.D.X., M.J.B., I.T., D.Y.L., S.G.D.), and Division of Cardiothoracic Surgery (C.H.S.), University of Utah, Salt Lake City. Dr Seidel is currently at the Institute for Cellular and Molecular Physiology, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Germany.
| | - Sutip Navankasattusas
- From Nora Eccles Harrison Cardiovascular Research and Training Institute (T.S., A.A., M.T.-F., S.G.D., F.B.S.), Molecular Medicine Program (S.N., N.A.D., D.Y.L., C.H.S.), Department of Bioengineering (A.A., F.B.S.), Division of Cardiovascular Medicine (W.D.X., M.J.B., I.T., D.Y.L., S.G.D.), and Division of Cardiothoracic Surgery (C.H.S.), University of Utah, Salt Lake City. Dr Seidel is currently at the Institute for Cellular and Molecular Physiology, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Germany
| | - Azmi Ahmad
- From Nora Eccles Harrison Cardiovascular Research and Training Institute (T.S., A.A., M.T.-F., S.G.D., F.B.S.), Molecular Medicine Program (S.N., N.A.D., D.Y.L., C.H.S.), Department of Bioengineering (A.A., F.B.S.), Division of Cardiovascular Medicine (W.D.X., M.J.B., I.T., D.Y.L., S.G.D.), and Division of Cardiothoracic Surgery (C.H.S.), University of Utah, Salt Lake City. Dr Seidel is currently at the Institute for Cellular and Molecular Physiology, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Germany
| | - Nikolaos A Diakos
- From Nora Eccles Harrison Cardiovascular Research and Training Institute (T.S., A.A., M.T.-F., S.G.D., F.B.S.), Molecular Medicine Program (S.N., N.A.D., D.Y.L., C.H.S.), Department of Bioengineering (A.A., F.B.S.), Division of Cardiovascular Medicine (W.D.X., M.J.B., I.T., D.Y.L., S.G.D.), and Division of Cardiothoracic Surgery (C.H.S.), University of Utah, Salt Lake City. Dr Seidel is currently at the Institute for Cellular and Molecular Physiology, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Germany
| | - Weining David Xu
- From Nora Eccles Harrison Cardiovascular Research and Training Institute (T.S., A.A., M.T.-F., S.G.D., F.B.S.), Molecular Medicine Program (S.N., N.A.D., D.Y.L., C.H.S.), Department of Bioengineering (A.A., F.B.S.), Division of Cardiovascular Medicine (W.D.X., M.J.B., I.T., D.Y.L., S.G.D.), and Division of Cardiothoracic Surgery (C.H.S.), University of Utah, Salt Lake City. Dr Seidel is currently at the Institute for Cellular and Molecular Physiology, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Germany
| | - Martin Tristani-Firouzi
- From Nora Eccles Harrison Cardiovascular Research and Training Institute (T.S., A.A., M.T.-F., S.G.D., F.B.S.), Molecular Medicine Program (S.N., N.A.D., D.Y.L., C.H.S.), Department of Bioengineering (A.A., F.B.S.), Division of Cardiovascular Medicine (W.D.X., M.J.B., I.T., D.Y.L., S.G.D.), and Division of Cardiothoracic Surgery (C.H.S.), University of Utah, Salt Lake City. Dr Seidel is currently at the Institute for Cellular and Molecular Physiology, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Germany
| | - Michael J Bonios
- From Nora Eccles Harrison Cardiovascular Research and Training Institute (T.S., A.A., M.T.-F., S.G.D., F.B.S.), Molecular Medicine Program (S.N., N.A.D., D.Y.L., C.H.S.), Department of Bioengineering (A.A., F.B.S.), Division of Cardiovascular Medicine (W.D.X., M.J.B., I.T., D.Y.L., S.G.D.), and Division of Cardiothoracic Surgery (C.H.S.), University of Utah, Salt Lake City. Dr Seidel is currently at the Institute for Cellular and Molecular Physiology, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Germany
| | - Iosif Taleb
- From Nora Eccles Harrison Cardiovascular Research and Training Institute (T.S., A.A., M.T.-F., S.G.D., F.B.S.), Molecular Medicine Program (S.N., N.A.D., D.Y.L., C.H.S.), Department of Bioengineering (A.A., F.B.S.), Division of Cardiovascular Medicine (W.D.X., M.J.B., I.T., D.Y.L., S.G.D.), and Division of Cardiothoracic Surgery (C.H.S.), University of Utah, Salt Lake City. Dr Seidel is currently at the Institute for Cellular and Molecular Physiology, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Germany
| | - Dean Y Li
- From Nora Eccles Harrison Cardiovascular Research and Training Institute (T.S., A.A., M.T.-F., S.G.D., F.B.S.), Molecular Medicine Program (S.N., N.A.D., D.Y.L., C.H.S.), Department of Bioengineering (A.A., F.B.S.), Division of Cardiovascular Medicine (W.D.X., M.J.B., I.T., D.Y.L., S.G.D.), and Division of Cardiothoracic Surgery (C.H.S.), University of Utah, Salt Lake City. Dr Seidel is currently at the Institute for Cellular and Molecular Physiology, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Germany
| | - Craig H Selzman
- From Nora Eccles Harrison Cardiovascular Research and Training Institute (T.S., A.A., M.T.-F., S.G.D., F.B.S.), Molecular Medicine Program (S.N., N.A.D., D.Y.L., C.H.S.), Department of Bioengineering (A.A., F.B.S.), Division of Cardiovascular Medicine (W.D.X., M.J.B., I.T., D.Y.L., S.G.D.), and Division of Cardiothoracic Surgery (C.H.S.), University of Utah, Salt Lake City. Dr Seidel is currently at the Institute for Cellular and Molecular Physiology, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Germany
| | - Stavros G Drakos
- From Nora Eccles Harrison Cardiovascular Research and Training Institute (T.S., A.A., M.T.-F., S.G.D., F.B.S.), Molecular Medicine Program (S.N., N.A.D., D.Y.L., C.H.S.), Department of Bioengineering (A.A., F.B.S.), Division of Cardiovascular Medicine (W.D.X., M.J.B., I.T., D.Y.L., S.G.D.), and Division of Cardiothoracic Surgery (C.H.S.), University of Utah, Salt Lake City. Dr Seidel is currently at the Institute for Cellular and Molecular Physiology, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Germany.
| | - Frank B Sachse
- From Nora Eccles Harrison Cardiovascular Research and Training Institute (T.S., A.A., M.T.-F., S.G.D., F.B.S.), Molecular Medicine Program (S.N., N.A.D., D.Y.L., C.H.S.), Department of Bioengineering (A.A., F.B.S.), Division of Cardiovascular Medicine (W.D.X., M.J.B., I.T., D.Y.L., S.G.D.), and Division of Cardiothoracic Surgery (C.H.S.), University of Utah, Salt Lake City. Dr Seidel is currently at the Institute for Cellular and Molecular Physiology, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Germany.
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7
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Abstract
Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.
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Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory and the Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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8
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Wang Y, Tsui H, Bolton EL, Wang X, Huang CLH, Solaro RJ, Ke Y, Lei M. Novel insights into mechanisms for Pak1-mediated regulation of cardiac Ca(2+) homeostasis. Front Physiol 2015; 6:76. [PMID: 25852566 PMCID: PMC4362298 DOI: 10.3389/fphys.2015.00076] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 02/25/2015] [Indexed: 11/13/2022] Open
Abstract
A series of recent studies report novel roles for Pak1, a key member of the highly conserved family of serine-threonine protein kinases regulated by Ras-related small G-proteins, Cdc42/Rac1, in cardiac physiology and cardioprotection. Previous studies had identified Pak1 in the regulation of hypertrophic remodeling that could potentially lead to heart failure. This article provides a review of more recent findings on the roles of Pak1 in cardiac Ca(2+) homeostasis. These findings identified crucial roles for Pak1 in cardiomyocyte Ca(2+) handling and demonstrated that it functions through unique mechanisms involving regulation of the post-transcriptional activity of key Ca(2+)-handling proteins, including the expression of Ca(2+)-ATPase SERCA2a, along with the speculative possibility of an involvement in the maintenance of transverse (T)-tubular structure. They highlight important regulatory functions of Pak1 in Ca(2+) homeostasis in cardiac cells, and identify novel potential therapeutic strategies directed at manipulation of Pak1 signaling for the management of cardiac disease, particularly heart failure.
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Affiliation(s)
- Yanwen Wang
- Department of Pharmacology, University of Oxford Oxford, UK
| | - Hoyee Tsui
- Faculty of Life Science, University of Manchester Manchester, UK
| | - Emma L Bolton
- Department of Pharmacology, University of Oxford Oxford, UK
| | - Xin Wang
- Faculty of Life Science, University of Manchester Manchester, UK
| | | | - R John Solaro
- Department of Physiology and Biophysics, University of Illinois Chicago, IL, USA
| | - Yunbo Ke
- Department of Physiology and Biophysics, University of Illinois Chicago, IL, USA
| | - Ming Lei
- Department of Pharmacology, University of Oxford Oxford, UK
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9
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Ke Y, Wang X, Jin XY, Solaro RJ, Lei M. PAK1 is a novel cardiac protective signaling molecule. Front Med 2014; 8:399-403. [PMID: 25416031 DOI: 10.1007/s11684-014-0380-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 10/15/2014] [Indexed: 12/19/2022]
Abstract
We review here the novel cardiac protective effects of the multifunctional enzyme, p21-activated kinase 1 (PAK1), a member of a serine/threonine protein kinase family. Despite the large body of evidence from studies in noncardiac tissue indicating that PAK1 activity is key in the regulation of a number of cellular functions, the role of PAK1 in the heart has only been revealed over the past few years. In this review, we assemble an overview of the recent findings on PAK1 signaling in the heart, particularly its cardiac protective effects. We present a model for PAK1 signaling that provides a mechanism for specifically affecting cardiac cellular processes in which regulation of protein phosphorylation states by protein phosphatase 2A (PP2A) predominates.We discuss the anti-adrenergic and antihypertrophic cardiac protective effects of PAK1, as well as its role in maintaining ventricular Ca(2+) homeostasis and electrophysiological stability under physiological, β-adrenergic and hypertrophic stress conditions.
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Affiliation(s)
- Yunbo Ke
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL, 60612, USA
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Wang Y, Tsui H, Ke Y, Shi Y, Li Y, Davies L, Cartwright EJ, Venetucci L, Zhang H, Terrar DA, Huang CLH, Solaro RJ, Wang X, Lei M. Pak1 is required to maintain ventricular Ca²⁺ homeostasis and electrophysiological stability through SERCA2a regulation in mice. Circ Arrhythm Electrophysiol 2014; 7:938-48. [PMID: 25217043 DOI: 10.1161/circep.113.001198] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND Impaired sarcoplasmic reticular Ca(2+) uptake resulting from decreased sarcoplasmic reticulum Ca(2+)-ATPase type 2a (SERCA2a) expression or activity is a characteristic of heart failure with its associated ventricular arrhythmias. Recent attempts at gene therapy of these conditions explored strategies enhancing SERCA2a expression and the activity as novel approaches to heart failure management. We here explore the role of Pak1 in maintaining ventricular Ca(2+) homeostasis and electrophysiological stability under both normal physiological and acute and chronic β-adrenergic stress conditions. METHODS AND RESULTS Mice with a cardiomyocyte-specific Pak1 deletion (Pak1(cko)), but not controls (Pak1(f/f)), showed high incidences of ventricular arrhythmias and electrophysiological instability during either acute β-adrenergic or chronic β-adrenergic stress leading to hypertrophy, induced by isoproterenol. Isolated Pak1(cko) ventricular myocytes correspondingly showed aberrant cellular Ca(2+) homeostasis. Pak1(cko) hearts showed an associated impairment of SERCA2a function and downregulation of SERCA2a mRNA and protein expression. Further explorations of the mechanisms underlying the altered transcriptional regulation demonstrated that exposure to control Ad-shC2 virus infection increased SERCA2a protein and mRNA levels after phenylephrine stress in cultured neonatal rat cardiomyocytes. This was abolished by the Pak1-knockdown in Ad-shPak1-infected neonatal rat cardiomyocytes and increased by constitutive overexpression of active Pak1 (Ad-CAPak1). We then implicated activation of serum response factor, a transcriptional factor well known for its vital role in the regulation of cardiogenesis genes in the Pak1-dependent regulation of SERCA2a. CONCLUSIONS These findings indicate that Pak1 is required to maintain ventricular Ca(2+) homeostasis and electrophysiological stability and implicate Pak1 as a novel regulator of cardiac SERCA2a through a transcriptional mechanism.
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Affiliation(s)
- Yanwen Wang
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.)
| | - Hoyee Tsui
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.)
| | - Yunbo Ke
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.)
| | - Ying Shi
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.)
| | - Yatong Li
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.)
| | - Laura Davies
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.)
| | - Elizabeth J Cartwright
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.)
| | - Luigi Venetucci
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.)
| | - Henggui Zhang
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.)
| | - Derek A Terrar
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.)
| | - Christopher L-H Huang
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.)
| | - R John Solaro
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.)
| | - Xin Wang
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.).
| | - Ming Lei
- From the Department of Pharmacology, University of Oxford, Oxford, United Kingdom (Y.W., D.A.T., M.L.); Institute of Cardiovascular Sciences, Faculty of Medicine and Human Sciences (Y.W., H.T., Y.L., L.D., E.J.C., L.V., M.L.), Faculty of Life Science (X.W.), School of Physics and Astronomy (H.Z.), University of Manchester, Manchester, United Kingdom; Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago (Y.K., R.J.S.); Department of Cardiovascular Diseases, Union Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China (Y.S., M.L.); Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom (C.L.-H.H.).
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Taglieri DM, Ushio-Fukai M, Monasky MM. P21-activated kinase in inflammatory and cardiovascular disease. Cell Signal 2014; 26:2060-9. [PMID: 24794532 DOI: 10.1016/j.cellsig.2014.04.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 04/27/2014] [Indexed: 02/09/2023]
Abstract
P-21 activated kinases, or PAKs, are serine-threonine kinases that serve a role in diverse biological functions and organ system diseases. Although PAK signaling has been the focus of many investigations, still our understanding of the role of PAK in inflammation is incomplete. This review consolidates what is known about PAK1 across several cell types, highlighting the role of PAK1 and PAK2 in inflammation in relation to NADPH oxidase activation. This review explores the physiological functions of PAK during inflammation, the role of PAK in several organ diseases with an emphasis on cardiovascular disease, and the PAK signaling pathway, including activators and targets of PAK. Also, we discuss PAK1 as a pharmacological anti-inflammatory target, explore the potentials and the limitations of the current pharmacological tools to regulate PAK1 activity during inflammation, and provide indications for future research. We conclude that a vast amount of evidence supports the idea that PAK is a central molecule in inflammatory signaling, thus making PAK1 itself a promising prospective pharmacological target.
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Affiliation(s)
- Domenico M Taglieri
- Department of Anesthesia and General Intensive Care Unit, Humanitas Research Hospital, Via Manzoni 56, Rozzano, 20089 (Milano), Italy.
| | - Masuko Ushio-Fukai
- Department of Pharmacology, Center for Lung and Vascular Biology, Center for Cardiovascular Research, University of Illinois at Chicago, 835 S. Wolcott Ave. E403 MSB, M/C868, Chicago, IL 60612, USA.
| | - Michelle M Monasky
- Cardiovascular Research Center, Humanitas Research Hospital, Via Manzoni 113, Rozzano, 20089 (Milano), Italy.
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DeSantiago J, Bare DJ, Xiao L, Ke Y, Solaro RJ, Banach K. p21-Activated kinase1 (Pak1) is a negative regulator of NADPH-oxidase 2 in ventricular myocytes. J Mol Cell Cardiol 2014; 67:77-85. [PMID: 24380729 PMCID: PMC3930036 DOI: 10.1016/j.yjmcc.2013.12.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 12/19/2013] [Accepted: 12/21/2013] [Indexed: 12/20/2022]
Abstract
Ischemic conditions reduce the activity of the p21-activated kinase (Pak1) resulting in increased arrhythmic activity. Triggered arrhythmic activity during ischemia is based on changes in cellular ionic balance and the cells Ca(2+) handling properties. In the current study we used isolated mouse ventricular myocytes (VMs) deficient for the expression of Pak1 (Pak1(-/-)) to determine the mechanism by which Pak1 influences the generation of arrhythmic activity during simulated ischemia. The Ca(2+) transient amplitude and kinetics did not significantly change in wild type (WT) and Pak1(-/-) VMs during 15 min of simulated ischemia. However, Pak1(-/-) VMs exhibited an exaggerated increase in [Ca(2+)]i, which resulted in spontaneous Ca(2+) release events and waves. The Ca(2+) overload in Pak1(-/-) VMs could be suppressed with a reverse mode blocker (KB-R7943) of the sodium calcium exchanger (NCX), a cytoplasmic scavenger of reactive oxygen species (ROS; TEMPOL) or a RAC1 inhibitor (NSC23766). Measurements of the cytoplasmic ROS levels revealed that decreased Pak1 activity in Pak1(-/-) VMs or VMs treated with the Pak1 inhibitor (IPA3) enhanced cellular ROS production. The Pak1 dependent increase in ROS was attenuated in VMs deficient for NADPH oxidase 2 (NOX2; p47(phox-/-)) or in VMs where NOX2 was inhibited (gp91ds-tat). Voltage clamp recordings showed increased NCX activity in Pak1(-/-) VMs that depended on enhanced NOX2 induced ROS production. The exaggerated Ca(2+) overload in Pak1(-/-) VMs could be mimicked by low concentrations of ouabain. Overall our data show that Pak1 is a critical negative regulator of NOX2 dependent ROS production and that a latent ROS dependent stimulation of NCX activity can predispose VMs to Ca(2+) overload under conditions where no significant changes in excitation-contraction coupling are yet evident.
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Affiliation(s)
- Jaime DeSantiago
- Center for Cardiovascular Research, University of Illinois at Chicago, 840 S. Wood Street, Chicago, IL 60612, USA; Department of Medicine, Section of Cardiology, University of Illinois at Chicago, 840 S. Wood Street, Chicago, IL 60612, USA
| | - Dan J Bare
- Center for Cardiovascular Research, University of Illinois at Chicago, 840 S. Wood Street, Chicago, IL 60612, USA; Department of Medicine, Section of Cardiology, University of Illinois at Chicago, 840 S. Wood Street, Chicago, IL 60612, USA
| | - Lei Xiao
- Center for Cardiovascular Research, University of Illinois at Chicago, 840 S. Wood Street, Chicago, IL 60612, USA; Department of Medicine, Section of Cardiology, University of Illinois at Chicago, 840 S. Wood Street, Chicago, IL 60612, USA; Pulmonary, Critical Care, Sleep and Allergy, University of Illinois at Chicago, 840 S. Wood Street, Chicago, IL 60612, USA
| | - Yunbo Ke
- Center for Cardiovascular Research, University of Illinois at Chicago, 840 S. Wood Street, Chicago, IL 60612, USA; Department of Physiology and Biophysics, University of Illinois at Chicago, 840 S. Wood Street, Chicago, IL 60612, USA
| | - R John Solaro
- Center for Cardiovascular Research, University of Illinois at Chicago, 840 S. Wood Street, Chicago, IL 60612, USA; Department of Physiology and Biophysics, University of Illinois at Chicago, 840 S. Wood Street, Chicago, IL 60612, USA
| | - Kathrin Banach
- Center for Cardiovascular Research, University of Illinois at Chicago, 840 S. Wood Street, Chicago, IL 60612, USA; Department of Medicine, Section of Cardiology, University of Illinois at Chicago, 840 S. Wood Street, Chicago, IL 60612, USA.
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Ke Y, Lei M, Wang X, Solaro RJ. Unique catalytic activities and scaffolding of p21 activated kinase-1 in cardiovascular signaling. Front Pharmacol 2013; 4:116. [PMID: 24098283 PMCID: PMC3784770 DOI: 10.3389/fphar.2013.00116] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 08/28/2013] [Indexed: 01/16/2023] Open
Abstract
P21 activated kinase-1 (Pak1) has diverse functions in mammalian cells. Although a large number of phosphoproteins have been designated as Pak1 substrates from in vitro studies, emerging evidence has indicated that Pak1 may function as a signaling molecule through a unique molecular mechanism – scaffolding. By scaffolding, Pak1 delivers signals through an auto-phosphorylation-induced conformational change without transfer of a phosphate group to its immediate downstream effector(s). Here we review evidence for this regulatory mechanism based on structural and functional studies of Pak1 in different cell types and research models as well as in vitro biochemical assays. We also discuss the implications of Pak1 scaffolding in disease-related signaling processes and the potential in cardiovascular drug development.
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Affiliation(s)
- Yunbo Ke
- Department of Physiology and Biophysics, University of Illinois at Chicago Chicago, IL, USA ; Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago Chicago, IL, USA
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