1
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Brennan S, Esposito S, Abdelaziz MIM, Martin CA, Makwana S, Sims MW, Squire IB, Sharma P, Chadwick AE, Rainbow RD. Selective protein kinase C inhibition switches time-dependent glucose cardiotoxicity to cardioprotection. Front Cardiovasc Med 2022; 9:997013. [PMID: 36158799 PMCID: PMC9489859 DOI: 10.3389/fcvm.2022.997013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/15/2022] [Indexed: 12/03/2022] Open
Abstract
Hyperglycaemia at the time of myocardial infarction has an adverse effect on prognosis irrespective of a prior diagnosis of diabetes, suggesting glucose is the damaging factor. In ex vivo models of ischaemia, we demonstrated that deleterious effects of acutely elevated glucose are PKCα/β-dependent, and providing PKCα/β are inhibited, elevated glucose confers cardioprotection. Short pre-treatments with high glucose were used to investigate time-dependent glucose cardiotoxicity, with PKCα/β inhibition investigated as a potential mechanism to reverse the toxicity. Freshly isolated non-diabetic rat cardiomyocytes were exposed to elevated glucose to investigate the time-dependence toxic effects. High glucose challenge for >7.5 min was cardiotoxic, proarrhythmic and lead to contractile failure, whilst cardiomyocytes exposed to metabolic inhibition following 5-min high glucose, displayed a time-dependent protection lasting ∼15 min. This protection was further enhanced with PKCα/β inhibition. Cardioprotection was measured as a delay in contractile failure and KATP channel activation, improved contractile and Ca2+ transient recovery and increased cell survival. Finally, the effects of pre-ischaemic treatment with high glucose in a whole-heart coronary ligation protocol, where protection was evident with PKCα/β inhibition. Selective PKCα/β inhibition enhances protection suggesting glycaemic control with PKC inhibition as a potential cardioprotective therapeutics in myocardial infarction and elective cardiac surgery.
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Affiliation(s)
- Sean Brennan
- Department of Cardiovascular, Metabolic Medicine and Liverpool Centre for Cardiovascular Sciences, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
- *Correspondence: Sean Brennan,
| | - Simona Esposito
- Department of Cardiovascular, Metabolic Medicine and Liverpool Centre for Cardiovascular Sciences, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom
| | - Muhammad I. M. Abdelaziz
- Department of Cardiovascular, Metabolic Medicine and Liverpool Centre for Cardiovascular Sciences, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Christopher A. Martin
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom
| | - Samir Makwana
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom
| | - Mark W. Sims
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom
| | - Iain B. Squire
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom
- Leicester NIHR Biomedical Research Centre, Glenfield General Hospital, Leicester, United Kingdom
| | - Parveen Sharma
- Department of Cardiovascular, Metabolic Medicine and Liverpool Centre for Cardiovascular Sciences, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Amy E. Chadwick
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, Liverpool, United Kingdom
| | - Richard D. Rainbow
- Department of Cardiovascular, Metabolic Medicine and Liverpool Centre for Cardiovascular Sciences, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
- Richard D. Rainbow,
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2
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Hammoud MK, Dietze R, Pesek J, Finkernagel F, Unger A, Bieringer T, Nist A, Stiewe T, Bhagwat AM, Nockher WA, Reinartz S, Müller-Brüsselbach S, Graumann J, Müller R. Arachidonic acid, a clinically adverse mediator in the ovarian cancer microenvironment, impairs JAK-STAT signaling in macrophages by perturbing lipid raft structures. Mol Oncol 2022; 16:3146-3166. [PMID: 35451191 PMCID: PMC9441005 DOI: 10.1002/1878-0261.13221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 03/29/2022] [Accepted: 04/20/2022] [Indexed: 11/08/2022] Open
Abstract
Survival of ovarian carcinoma is associated with the abundance of immunosuppressed CD163highCD206high tumor‐associated macrophages (TAMs) and high levels of arachidonic acid (AA) in the tumor microenvironment. Here, we show that both associations are functionally linked. Transcriptional profiling revealed that high CD163 and CD206/MRC1 expression in TAMs is strongly associated with an inhibition of cytokine‐triggered signaling, mirrored by an impaired transcriptional response to interferons and IL‐6 in monocyte‐derived macrophages by AA. This inhibition of pro‐inflammatory signaling is caused by dysfunctions of the cognate receptors, indicated by the inhibition of JAK1, JAK2, STAT1, and STAT3 phosphorylation, and by the displacement of the interferon receptor IFNAR1, STAT1 and other immune‐regulatory proteins from lipid rafts. AA exposure led to a dramatic accumulation of free AA in lipid rafts, which appears to be mechanistically crucial, as the inhibition of its incorporation into phospholipids did not affect the AA‐mediated interference with STAT1 phosphorylation. Inhibition of interferon‐triggered STAT1 phosphorylation by AA was reversed by water‐soluble cholesterol, known to prevent the perturbation of lipid raft structure by AA. These findings suggest that the pharmacologic restoration of lipid raft functions in TAMs may contribute to the development new therapeutic approaches.
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Affiliation(s)
- Mohamad K Hammoud
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany
| | - Raimund Dietze
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany
| | - Jelena Pesek
- Medical Mass Spectrometry Core Facility, Philipps University, Marburg, Germany
| | - Florian Finkernagel
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany
| | - Annika Unger
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany
| | - Tim Bieringer
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany.,Hochschule Landshut, 84036, Landshut, Germany
| | - Andrea Nist
- Genomics Core Facility, Philipps University, Marburg, Germany
| | - Thorsten Stiewe
- Genomics Core Facility, Philipps University, Marburg, Germany
| | - Aditya M Bhagwat
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany.,The German Centre for Cardiovascular Research (DZHK), Partner Site Rhine-Main, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - W Andreas Nockher
- Medical Mass Spectrometry Core Facility, Philipps University, Marburg, Germany
| | - Silke Reinartz
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany
| | | | - Johannes Graumann
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany.,The German Centre for Cardiovascular Research (DZHK), Partner Site Rhine-Main, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.,Institute for Translational Proteomics, Philipps University, Marburg, Germany
| | - Rolf Müller
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany
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3
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Weng L, Gong Y, Culver J, Gardell SJ, Petucci C, Morse AM, Frye RF, Turner ST, Chapman A, Boerwinkle E, Gums J, Beitelshees AL, Borum PR, Johnson JA, Garrett TJ, McIntyre LM, Cooper-DeHoff RM. Presence of arachidonoyl-carnitine is associated with adverse cardiometabolic responses in hypertensive patients treated with atenolol. Metabolomics 2016; 12:160. [PMID: 28217401 PMCID: PMC5313050 DOI: 10.1007/s11306-016-1098-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Atenolol, a commonly prescribed β blocker for hypertension, is also associated with adverse cardiometabolic effects such as hyperglycemia and dyslipidemia. Knowledge of the mechanistic underpinnings of these adverse effects of atenolol is incomplete. OBJECTIVE We sought to identify biomarkers associated with risk for these untoward effects of atenolol. We measured baseline blood serum levels of acylcarnitines (ACs) that are involved in a host of different metabolic pathways, to establish associations with adverse cardiometabolic responses after atenolol treatment. METHODS Serum samples from Caucasian hypertensive patients (n = 224) who were treated with atenolol in the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) study were interrogated using a quantitative LC/MS assay for a large number of unique ACs in serum. For the 23 ACs that were detected in serum from ≥80 % of all patients, we conducted linear regression for changes in cardiometabolic factors with baseline AC levels, baseline cardiometabolic factors, age, sex, and BMI as covariates. For the 5 ACs that were detected in serum from 20 to 79 % of the patients, we similarly modeled changes in cardiometabolic factors, but with specifying the AC as present/absent in the regression. RESULTS Among the 28 ACs, the presence (vs. absence) of arachidonoyl-carnitine (C20:4) was significantly associated with increased glucose (p = 0.0002), and was nominally associated with decreased plasma HDL-C (p = 0.017) and with less blood pressure (BP) lowering (p = 0.006 for systolic BP, p = 0.002 for diastolic BP), after adjustment. CONCLUSION Serum level of C20:4 is a promising biomarker to predict adverse cardiometabolic responses including glucose and poor antihypertensive response to atenolol.
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Affiliation(s)
- Liming Weng
- Department of Pharmacotherapy and Translational Research and Division of Cardiovascular Medicine, Colleges of Pharmacy and Medicine, Center for Pharmacogenomics, University of Florida, P.O. Box 100486, Gainesville, FL 32610-0486, USA
| | - Yan Gong
- Department of Pharmacotherapy and Translational Research and Division of Cardiovascular Medicine, Colleges of Pharmacy and Medicine, Center for Pharmacogenomics, University of Florida, P.O. Box 100486, Gainesville, FL 32610-0486, USA
| | - Jeffrey Culver
- Metabolomics Core, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL, USA; Southeast Center for Integrated Metabolomics (SECIM), University of Florida, Gainesville, FL, USA
| | - Stephen J Gardell
- Metabolomics Core, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL, USA; Southeast Center for Integrated Metabolomics (SECIM), University of Florida, Gainesville, FL, USA
| | - Christopher Petucci
- Metabolomics Core, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL, USA; Southeast Center for Integrated Metabolomics (SECIM), University of Florida, Gainesville, FL, USA
| | - Alison M Morse
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Reginald F Frye
- Department of Pharmacotherapy and Translational Research and Division of Cardiovascular Medicine, Colleges of Pharmacy and Medicine, Center for Pharmacogenomics, University of Florida, P.O. Box 100486, Gainesville, FL 32610-0486, USA
| | - Stephen T Turner
- Division of Nephrology and Hypertension, Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Arlene Chapman
- Renal Division, School of Medicine, Emory University, Atlanta, GA, USA
| | - Eric Boerwinkle
- Human Genetics and Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX, USA
| | - John Gums
- Department of Pharmacotherapy and Translational Research and Division of Cardiovascular Medicine, Colleges of Pharmacy and Medicine, Center for Pharmacogenomics, University of Florida, P.O. Box 100486, Gainesville, FL 32610-0486, USA
| | - Amber L Beitelshees
- Department of Medicine and Program in Personalized and Genomic Medicine, University of Maryland, Baltimore, MD, USA
| | - Peggy R Borum
- Department of Food Science and Human Nutrition, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA
| | - Julie A Johnson
- Department of Pharmacotherapy and Translational Research and Division of Cardiovascular Medicine, Colleges of Pharmacy and Medicine, Center for Pharmacogenomics, University of Florida, P.O. Box 100486, Gainesville, FL 32610-0486, USA
| | - Timothy J Garrett
- Southeast Center for Integrated Metabolomics (SECIM), University of Florida, Gainesville, FL, USA; Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Lauren M McIntyre
- Southeast Center for Integrated Metabolomics (SECIM), University of Florida, Gainesville, FL, USA; Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Rhonda M Cooper-DeHoff
- Department of Pharmacotherapy and Translational Research and Division of Cardiovascular Medicine, Colleges of Pharmacy and Medicine, Center for Pharmacogenomics, University of Florida, P.O. Box 100486, Gainesville, FL 32610-0486, USA
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4
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Scruggs SB, Wang D, Ping P. PRKCE gene encoding protein kinase C-epsilon-Dual roles at sarcomeres and mitochondria in cardiomyocytes. Gene 2016; 590:90-6. [PMID: 27312950 DOI: 10.1016/j.gene.2016.06.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 05/23/2016] [Accepted: 06/05/2016] [Indexed: 12/26/2022]
Abstract
Protein kinase C-epsilon (PKCε) is an isoform of a large PKC family of enzymes that has a variety of functions in different cell types. Here we discuss two major roles of PKCε in cardiac muscle cells; specifically, its role in regulating cardiac muscle contraction via targeting the sarcomeric proteins, as well as modulating cardiac cell energy production and metabolism by targeting cardiac mitochondria. The importance of PKCε action is described within the context of intracellular localization, as substrate selectivity and specificity is achieved through spatiotemporal targeting of PKCε. Accordingly, the role of PKCε in regulating myocardial function in physiological and pathological states has been documented in both cardioprotection and cardiac hypertrophy.
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Affiliation(s)
- Sarah B Scruggs
- Departments of Physiology, Medicine (Cardiology) and Bioinformatics, NIH BD2K Center of Excellence for Biomedical Computing, University of California Los Angeles, Los Angeles, CA 90095, USA.
| | - Ding Wang
- Departments of Physiology, Medicine (Cardiology) and Bioinformatics, NIH BD2K Center of Excellence for Biomedical Computing, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Peipei Ping
- Departments of Physiology, Medicine (Cardiology) and Bioinformatics, NIH BD2K Center of Excellence for Biomedical Computing, University of California Los Angeles, Los Angeles, CA 90095, USA.
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5
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Reinartz S, Finkernagel F, Adhikary T, Rohnalter V, Schumann T, Schober Y, Nockher WA, Nist A, Stiewe T, Jansen JM, Wagner U, Müller-Brüsselbach S, Müller R. A transcriptome-based global map of signaling pathways in the ovarian cancer microenvironment associated with clinical outcome. Genome Biol 2016; 17:108. [PMID: 27215396 PMCID: PMC4877997 DOI: 10.1186/s13059-016-0956-6] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 04/15/2016] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Soluble protein and lipid mediators play essential roles in the tumor environment, but their cellular origins, targets, and clinical relevance are only partially known. We have addressed this question for the most abundant cell types in human ovarian carcinoma ascites, namely tumor cells and tumor-associated macrophages. RESULTS Transcriptome-derived datasets were adjusted for errors caused by contaminating cell types by an algorithm using expression data derived from pure cell types as references. These data were utilized to construct a network of autocrine and paracrine signaling pathways comprising 358 common and 58 patient-specific signaling mediators and their receptors. RNA sequencing based predictions were confirmed for several proteins and lipid mediators. Published expression microarray results for 1018 patients were used to establish clinical correlations for a number of components with distinct cellular origins and target cells. Clear associations with early relapse were found for STAT3-inducing cytokines, specific components of WNT and fibroblast growth factor signaling, ephrin and semaphorin axon guidance molecules, and TGFβ/BMP-triggered pathways. An association with early relapse was also observed for secretory macrophage-derived phospholipase PLA2G7, its product arachidonic acid (AA) and signaling pathways controlled by the AA metabolites PGE2, PGI2, and LTB4. By contrast, the genes encoding norrin and its receptor frizzled 4, both selectively expressed by cancer cells and previously not linked to tumor suppression, show a striking association with a favorable clinical course. CONCLUSIONS We have established a signaling network operating in the ovarian cancer microenvironment with previously unidentified pathways and have defined clinically relevant components within this network.
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Affiliation(s)
- Silke Reinartz
- Clinic for Gynecology, Gynecological Oncology and Gynecological Endocrinology, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - Florian Finkernagel
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, Hans-Meerwein-Str. 3, Marburg, 35043, Germany
| | - Till Adhikary
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, Hans-Meerwein-Str. 3, Marburg, 35043, Germany
| | - Verena Rohnalter
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, Hans-Meerwein-Str. 3, Marburg, 35043, Germany
| | - Tim Schumann
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, Hans-Meerwein-Str. 3, Marburg, 35043, Germany
| | - Yvonne Schober
- Metabolomics Core Facility and Institute of Laboratory Medicine and Pathobiochemistry, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - W Andreas Nockher
- Metabolomics Core Facility and Institute of Laboratory Medicine and Pathobiochemistry, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - Andrea Nist
- Genomics Core Facility, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - Thorsten Stiewe
- Genomics Core Facility, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - Julia M Jansen
- Clinic for Gynecology, Gynecological Oncology and Gynecological Endocrinology, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - Uwe Wagner
- Clinic for Gynecology, Gynecological Oncology and Gynecological Endocrinology, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - Sabine Müller-Brüsselbach
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, Hans-Meerwein-Str. 3, Marburg, 35043, Germany
| | - Rolf Müller
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, Hans-Meerwein-Str. 3, Marburg, 35043, Germany.
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6
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Huang YH, Su YS, Chang CJ, Sun WH. Heteromerization of G2A and OGR1 enhances proton sensitivity and proton-induced calcium signals. J Recept Signal Transduct Res 2016; 36:633-644. [PMID: 27049592 DOI: 10.3109/10799893.2016.1155064] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Proton-sensing G-protein-coupled receptors (GPCRs; OGR1, GPR4, G2A, TDAG8), with full activation at pH 6.4 ∼ 6.8, are important to pH homeostasis, immune responses and acid-induced pain. Although G2A mediates the G13-Rho pathway in response to acid, whether G2A activates Gs, Gi or Gq proteins remains debated. In this study, we examined the response of this fluorescence protein-tagged OGR1 family to acid stimulation in HEK293T cells. G2A did not generate detectable intracellular calcium or cAMP signals or show apparent receptor redistribution with moderate acid (pH ≥ 6.0) stimulation but reduced cAMP accumulation under strong acid stimulation (pH ≤ 5.5). Surprisingly, coexpression of OGR1- and G2A-enhanced proton sensitivity and proton-induced calcium signals. This alteration is attributed to oligomerization of OGR1 and G2A. The oligomeric potential locates receptors at a specific site, which leads to enhanced proton-induced calcium signals through channels.
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Affiliation(s)
- Ya-Han Huang
- a Department of Life Sciences , National Central University , Jhongli , Taiwan and
| | - Yeu-Shiuan Su
- a Department of Life Sciences , National Central University , Jhongli , Taiwan and
| | - Chung-Jen Chang
- a Department of Life Sciences , National Central University , Jhongli , Taiwan and
| | - Wei-Hsin Sun
- a Department of Life Sciences , National Central University , Jhongli , Taiwan and.,b Center for Biotechnology and Biomedical Engineering, National Central University , Jhongli , Taiwan
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7
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McGeachie MJ, Dahlin A, Qiu W, Croteau-Chonka DC, Savage J, Wu AC, Wan ES, Sordillo JE, Al-Garawi A, Martinez FD, Strunk RC, Lemanske RF, Liu AH, Raby BA, Weiss S, Clish CB, Lasky-Su JA. The metabolomics of asthma control: a promising link between genetics and disease. IMMUNITY INFLAMMATION AND DISEASE 2015; 3:224-38. [PMID: 26421150 PMCID: PMC4578522 DOI: 10.1002/iid3.61] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 03/26/2015] [Accepted: 03/27/2015] [Indexed: 12/12/2022]
Abstract
Short-acting β agonists (e.g., albuterol) are the most commonly used medications for asthma, a disease that affects over 300 million people in the world. Metabolomic profiling of asthmatics taking β agonists presents a new and promising resource for identifying the molecular determinants of asthma control. The objective is to identify novel genetic and biochemical predictors of asthma control using an integrative "omics" approach. We generated lipidomic data by liquid chromatography tandem mass spectrometry (LC-MS), - using plasma samples from 20 individuals with asthma. The outcome of interest was a binary indicator of asthma control defined by the use of albuterol inhalers in the preceding week. We integrated metabolomic data with genome-wide genotype, gene expression, and methylation data of this cohort to identify genomic and molecular indicators of asthma control. A Conditional Gaussian Bayesian Network (CGBN) was generated using the strongest predictors from each of these analyses. Integrative and metabolic pathway over-representation analyses (ORA) identified enrichment of known biological pathways within the strongest molecular determinants. Of the 64 metabolites measured, 32 had known identities. The CGBN model based on four SNPs (rs9522789, rs7147228, rs2701423, rs759582) and two metabolites-monoHETE_0863 and sphingosine-1-phosphate (S1P) could predict asthma control with an AUC of 95%. Integrative ORA identified 17 significantly enriched pathways related to cellular immune response, interferon signaling, and cytokine-related signaling, for which arachidonic acid, PGE2 and S1P, in addition to six genes (CHN1, PRKCE, GNA12, OASL, OAS1, and IFIT3) appeared to drive the pathway results. Of these predictors, S1P, GNA12, and PRKCE were enriched in the results from integrative and metabolic ORAs. Through an integrative analysis of metabolomic, genomic, and methylation data from a small cohort of asthmatics, we implicate altered metabolic pathways, related to sphingolipid metabolism, in asthma control. These results provide insight into the pathophysiology of asthma control.
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Affiliation(s)
- Michael J McGeachie
- Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School Boston, Massachusetts, USA
| | - Amber Dahlin
- Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School Boston, Massachusetts, USA
| | - Weiliang Qiu
- Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School Boston, Massachusetts, USA
| | - Damien C Croteau-Chonka
- Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School Boston, Massachusetts, USA
| | - Jessica Savage
- Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School Boston, Massachusetts, USA
| | - Ann Chen Wu
- Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School Boston, Massachusetts, USA ; Children's Hospital and Harvard Medical School Boston, Massachusetts, USA ; Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute Boston, Massachusetts, USA
| | - Emily S Wan
- Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School Boston, Massachusetts, USA
| | - Joanne E Sordillo
- Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School Boston, Massachusetts, USA
| | - Amal Al-Garawi
- Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School Boston, Massachusetts, USA
| | - Fernando D Martinez
- Arizona Respiratory Center and BIO5 Institute, University of Arizona Tucson, Arizona, USA
| | - Robert C Strunk
- Department of Pediatrics, Division of Allergy, Immunology and Pulmonary Medicine, Washington University School of Medicine St. Louis, Missouri, USA
| | - Robert F Lemanske
- University of Wisconsin School of Medicine and Public Health Madison, Wisconsin, USA
| | - Andrew H Liu
- Department of Pediatrics, Division of Allergy and Clinical Immunology, National Jewish Health and University of Colorado School of Medicine Denver, Colorado, USA
| | - Benjamin A Raby
- Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School Boston, Massachusetts, USA
| | - Scott Weiss
- Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School Boston, Massachusetts, USA
| | | | - Jessica A Lasky-Su
- Department of Medicine, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School Boston, Massachusetts, USA
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8
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Kukkonen JP. Lipid signaling cascades of orexin/hypocretin receptors. Biochimie 2013; 96:158-65. [PMID: 23810911 DOI: 10.1016/j.biochi.2013.06.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 06/18/2013] [Indexed: 11/18/2022]
Abstract
Orexins - orexin-A and orexin-B - are neuropeptides with significant role in regulation of fundamental physiological processes such as sleep-wakefulness cycle. Orexins act via G-protein-coupled OX1 and OX2 receptors, which are found, in addition to the central nervous system, also in a number of peripheral organs. Orexin receptors show high degree of signaling promiscuity. One particularly prominent way of signaling for these receptors is via phospholipase cascades, including the phospholipase C, phospholipase D and phospholipase A2 cascades, and also diacylglycerol lipase and phosphoinositide-3-kinase pathways. Most analyses have been performed in recombinant cells; there are indications of some of these cascades in native cells while the significance of other cascades remains to be shown. In this review, I present these pathways, their activation mechanisms and their physiological significance.
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Key Words
- 2-AG
- 2-arachidonoylglycerol
- AA
- CNS
- DAG
- DAG lipase
- DAGL
- DOG
- ERK
- Endocannabinoid
- G-protein-coupled receptor
- GPCR
- GPL
- Hypocretin
- IP(3)
- Ion fluxes
- KB-R7943
- MAFP
- N-acyl-phosphatidylethanolamine
- N-arachidonoylethanolamine
- NAPE
- NSCC
- OX(1)
- OX(2)
- Orexin
- PA
- PC
- PC-PLC
- PC-specific PLC
- PDK1
- PI
- PI3K
- PIP
- PIP(2)
- PIP(3)
- PIs
- PKB, PKC and PKD
- PLA(1), PLA(2), PLB, PLC and PLD
- Phospholipase
- TRP (channel)
- U73122
- a NCX inhibitor
- a PLC inhibitor
- a cPLA(2)α/ζ inhibitor
- anandamide
- arachidonic acid
- cPLA(2) and iPLA(2)
- central nervous system
- cytosolic (Ca(2+)-dependent) and intracellular (Ca(2+)-independent) PLA(2), respectively
- diacylglycerol
- dioctanoylglycerol
- extracellular signal-regulated kinase
- glycerophospholipid
- inositol-1,4,5-trisphosphate
- lyso(glycero)phospholipid
- lysoGPL
- lysoPA
- lysophosphatidic acid
- methyl arachidonyl fluorophosphonate
- non-selective cation channel
- orexin 1 receptor
- orexin 2 receptor
- phosphatidic acid
- phosphatidylcholine
- phosphatidylinositol
- phosphatidylinositol-3,4,5-trisphosphate
- phosphatidylinositol-4,5-bisphosphate
- phosphatidylinositolmonophosphate
- phosphatidylinositols (including differentially phosphorylated species PI, PIP, PIP(2) and PIP(3))
- phosphoinositide-3-kinase
- phosphoinositide-dependent kinase 1
- phospholipase A(1), A(2), B, C and D, respectively
- protein kinase B, C and D, respectively
- pyrrophenone
- transient receptor potential (channel)
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Affiliation(s)
- Jyrki P Kukkonen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, POB 66, FIN-00014, University of Helsinki, Finland.
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9
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Balogh G, Péter M, Glatz A, Gombos I, Török Z, Horváth I, Harwood JL, Vígh L. Key role of lipids in heat stress management. FEBS Lett 2013; 587:1970-80. [PMID: 23684645 DOI: 10.1016/j.febslet.2013.05.016] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 05/06/2013] [Indexed: 12/15/2022]
Abstract
Heat stress is a common and, therefore, an important environmental impact on cells and organisms. While much attention has been paid to severe heat stress, moderate temperature elevations are also important. Here we discuss temperature sensing and how responses to heat stress are not necessarily dependent on denatured proteins. Indeed, it is clear that membrane lipids have a pivotal function. Details of membrane lipid changes and the associated production of signalling metabolites are described and suggestions made as to how the interconnected signalling network could be modified for helpful intervention in disease.
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Affiliation(s)
- Gábor Balogh
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, H-6701 Szeged, Hungary
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10
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Biophysical Forces Modulate the Costamere and Z-Disc for Sarcomere Remodeling in Heart Failure. BIOPHYSICS OF THE FAILING HEART 2013. [DOI: 10.1007/978-1-4614-7678-8_7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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Ablation of the cardiac-specific gene leucine-rich repeat containing 10 (Lrrc10) results in dilated cardiomyopathy. PLoS One 2012; 7:e51621. [PMID: 23236519 PMCID: PMC3517560 DOI: 10.1371/journal.pone.0051621] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 11/02/2012] [Indexed: 01/06/2023] Open
Abstract
Leucine-rich repeat containing 10 (LRRC10) is a cardiac-specific protein exclusively expressed in embryonic and adult cardiomyocytes. However, the role of LRRC10 in mammalian cardiac physiology remains unknown. To determine if LRRC10 is critical for cardiac function, Lrrc10-null (Lrrc10−/−) mice were analyzed. Lrrc10−/− mice exhibit prenatal systolic dysfunction and dilated cardiomyopathy in postnatal life. Importantly, Lrrc10−/− mice have diminished cardiac performance in utero, prior to ventricular dilation observed in young adults. We demonstrate that LRRC10 endogenously interacts with α-actinin and α-actin in the heart and all actin isoforms in vitro. Gene expression profiling of embryonic Lrrc10−/− hearts identified pathways and transcripts involved in regulation of the actin cytoskeleton to be significantly upregulated, implicating dysregulation of the actin cytoskeleton as an early defective molecular signal in the absence of LRRC10. In contrast, microarray analyses of adult Lrrc10−/− hearts identified upregulation of oxidative phosphorylation and cardiac muscle contraction pathways during the progression of dilated cardiomyopathy. Analyses of hypertrophic signal transduction pathways indicate increased active forms of Akt and PKCε in adult Lrrc10−/− hearts. Taken together, our data demonstrate that LRRC10 is essential for proper mammalian cardiac function. We identify Lrrc10 as a novel dilated cardiomyopathy candidate gene and the Lrrc10−/− mouse model as a unique system to investigate pediatric cardiomyopathy.
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12
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Jin W, Brown AT, Murphy AM. Cardiac myofilaments: from proteome to pathophysiology. Proteomics Clin Appl 2012; 2:800-10. [PMID: 21136880 DOI: 10.1002/prca.200780075] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This review addresses the functional consequences of altered post-translational modifications of cardiac myofilament proteins in cardiac diseases such as heart failure and ischemia. The modifications of thick and thin filament proteins as well as titin are addressed. Understanding the functional consequences of altered protein modifications is an essential step in the development of targeted therapies for common cardiac diseases.
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Affiliation(s)
- Wenhai Jin
- Departments of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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13
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Garcia B, Martinez-de-Mena R, Obregon MJ. Arachidonic acid stimulates DNA synthesis in brown preadipocytes through the activation of protein kinase C and MAPK. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:1309-15. [PMID: 22766489 DOI: 10.1016/j.bbalip.2012.06.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 05/30/2012] [Accepted: 06/24/2012] [Indexed: 11/27/2022]
Abstract
Arachidonic acid (AA) is a polyunsaturated fatty acid that stimulates the proliferation of many cellular types. We studied the mitogenic potential of AA in rat brown preadipocytes in culture and the signaling pathways involved. AA is a potent mitogen which induces 4-fold DNA synthesis in brown preadipocytes. The AA mitogenic effect increases by NE addition. AA also increases the mitogenic action of different growth factor combinations. Other unsaturated and saturated fatty acids do not stimulate DNA synthesis to the same extent as AA. We analyzed the role of PKC and MEK/MAPK signaling pathways. PKC inhibition by bisindolilmaleimide I (BIS) abolishes AA and phorbol ester stimulation of DNA synthesis and reduces the mitogenic activity of different growth factors in brown preadipocytes. Brown preadipocytes in culture express PKC α, δ, ε and ζ isoforms. Pretreatment with high doses of the phorbol ester PDBu, induces downregulation of PKCs ε and δ and reproduces the effect of BIS indicating that AA-dependent induction of DNA synthesis requires PKC activity. AA also activates MEK/MAPK pathway and the inhibition of MEK activity inhibits AA stimulation of DNA synthesis and brown adipocyte proliferation. Inhibition of PKC δ by rottlerin abolishes AA-dependent stimulation of DNA synthesis and MAPK activation, whereas PKC ε inhibition does not produce any effect. In conclusion, our results identify AA as a potent mitogen for brown adipocytes and demonstrate the involvement of the PDBu-sensitive PKC δ isoform and MEK/MAPK pathway in AA-induced proliferation of brown adipocytes. Increased proliferative activity might increase the thermogenic capacity of brown fat.
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Affiliation(s)
- Bibian Garcia
- Depart. Fisiopatologia Endocrina y del Sistema Nervioso, Inst. Investigaciones Biomedicas, Centro mixto (CSIC-UAM), Madrid, Spain
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14
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Abstract
Berbamine (BM), a natural compound derived from Berberis vulgaris L, has been reported to inhibit cardiac contractile function at higher concentrations. Here, we report that BM had concentration-dependent biphasic effects on myocardial contraction in Langendorff-perfused rat hearts, that is, at lower concentrations (30-100 nM), it displayed positive inotropic and lusitropic effects, whereas at a higher concentration of 1 μM, it caused a negative inotropic effect after an initially weak increase. These effects were further confirmed in cardiomyocytes isolated from the left ventricles of rats. Moreover, the increased cell shortening by BM at concentrations from 0.1 to 100 nM was not associated with an alteration of intracellular Ca transients. Consistently, at 30 nM, BM shifted the cell shortening--Ca transient relationship curve induced by cumulative elevation of extracellular Ca concentration to the left. Furthermore, BM significantly increased membrane-bound but not filament-bound protein kinase C epsilon (PKCε) in the isolated hearts and cardiomyocytes. Such a translocation was inhibited by PKCε-specific inhibitor PKCε V1-2 concomitant with the abolishment of the BM-induced increase in contraction. These findings reveal the positive inotropic effect of BM in the myocardium and demonstrate that BM increases myocardial contractility by increasing myofilament Ca sensitivity via a PKCε-dependent signaling pathway.
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15
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Protein kinase C depresses cardiac myocyte power output and attenuates myofilament responses induced by protein kinase A. J Muscle Res Cell Motil 2012; 33:439-48. [PMID: 22527640 DOI: 10.1007/s10974-012-9294-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 04/09/2012] [Indexed: 01/13/2023]
Abstract
Following activation by G-protein-coupled receptor agonists, protein kinase C (PKC) modulates cardiac myocyte function by phosphorylation of intracellular targets including myofilament proteins cardiac troponin I (cTnI) and cardiac myosin binding protein C (cMyBP-C). Since PKC phosphorylation has been shown to decrease myofibril ATPase activity, we hypothesized that PKC phosphorylation of cTnI and cMyBP-C will lower myocyte power output and, in addition, attenuate the elevation in power in response to protein kinase A (PKA)-mediated phosphorylation. We compared isometric force and power generating capacity of rat skinned cardiac myocytes before and after treatment with the catalytic subunit of PKC. PKC increased phosphorylation levels of cMyBP-C and cTnI and decreased both maximal Ca(2+) activated force and Ca(2+) sensitivity of force. Moreover, during submaximal Ca(2+) activations PKC decreased power output by 62 %, which arose from both the fall in force and slower loaded shortening velocities since depressed power persisted even when force levels were matched before and after PKC. In addition, PKC blunted the phosphorylation of cTnI by PKA, reduced PKA-induced spontaneous oscillatory contractions, and diminished PKA-mediated elevations in myocyte power. To test whether altered thin filament function plays an essential role in these contractile changes we investigated the effects of chronic cTnI pseudo-phosphorylation on myofilament function using myocyte preparations from transgenic animals in which either only PKA phosphorylation sites (Ser-23/Ser-24) (PP) or both PKA and PKC phosphorylation sites (Ser-23/Ser-24/Ser-43/Ser-45/T-144) (All-P) were replaced with aspartic acid. Cardiac myocytes from All-P transgenic mice exhibited reductions in maximal force, Ca(2+) sensitivity of force, and power. Similarly diminished power generating capacity was observed in hearts from All-P mice as determined by in situ pressure-volume measurements. These results imply that PKC-mediated phosphorylation of cTnI plays a dominant role in depressing contractility, and, thus, increased PKC isozyme activity may contribute to maladaptive behavior exhibited during the progression to heart failure.
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16
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Chen L, Meng Q, Yu X, Li C, Zhang C, Cui C, Luo D. Possible mechanisms underlying the biphasic regulatory effects of arachidonic acid on Ca2+ signaling in HEK293 cells. Cell Signal 2012; 24:1565-72. [PMID: 22484156 DOI: 10.1016/j.cellsig.2012.03.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 03/21/2012] [Accepted: 03/21/2012] [Indexed: 12/01/2022]
Abstract
Arachidonic acid (AA), an endogenous lipid signal molecule released from membrane upon cell activation, modulates intracellular Ca(2+) ([Ca(2+)](i)) signaling positively and negatively. However, the mechanisms underlying the biphasic effects of AA are rather obscure. Using probes for measurements of [Ca(2+)](i) and fluidity of plasma membrane (PM)/endoplasmic reticulum (ER), immunostaining, immunoblotting and shRNA interference approaches, we found that AA at low concentration, 3 μM, reduced the PM fluidity by activating PKCα and PKCβII translocation to PM and also the ER fluidity directly. In accordance, 3 μM AA did not impact the basal [Ca(2+)](i) but significantly suppressed the thapsigargin-induced Ca(2+) release and Ca(2+) influx. Inhibition of PKC with Gö6983 or knockdown of PKCα or PKCβ using shRNA significantly attenuated the inhibitory effects of 3 μM AA on PM fluidity and agonist-induced Ca(2+) signal. However, AA at high concentration, 30 μM, caused robust release and entry of Ca(2+) accompanied by a facilitated PM fluidity but decreased ER fluidity and dramatic PKCβI and PKCβII redistribution in the ER. Compared with ursodeoxycholate acid, a membrane stabilizing agent that only inhibited the 30 μM AA-induced Ca(2+) influx by 45%, Gd(3+) at concentration of 10 μM could completely abolish both release and entry of Ca(2+) induced by AA, suggesting that the potentiated PM fluidity is not the only reason for AA eliciting Ca(2+) signal. Therefore, the study herein demonstrates that a lowered PM fluidity by PKC activation and a direct ER stabilization contribute significantly for AA downregulation of [Ca(2+)](i) response, while Gd(3+)-sensitive 'pores' in PM/ER play an important role in AA-induced Ca(2+) signal in HEK293 cells.
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Affiliation(s)
- Lihong Chen
- Department of Pharmacology, School of Chemical Biology & Pharmaceutical Sciences, Capital Medical University, Beijing, PR China
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17
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Duquesnes N, Lezoualc'h F, Crozatier B. PKC-delta and PKC-epsilon: foes of the same family or strangers? J Mol Cell Cardiol 2011; 51:665-73. [PMID: 21810427 DOI: 10.1016/j.yjmcc.2011.07.013] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 06/24/2011] [Accepted: 07/15/2011] [Indexed: 11/30/2022]
Abstract
Protein kinase C (PKC) is a family of 10 serine/threonine kinases divided into 3 subfamilies, classical, novel and atypical classes. Two PKC isozymes of the novel group, PKCε and PKCδ, have different and sometimes opposite effects. PKCε stimulates cell growth and differentiation while PKCδ is apoptotic. In the heart, they are among the most expressed PKC isozymes and they are opposed in the preconditioning process with a positive role of PKCε and an inhibiting role of PKCδ. The goal of this review is to analyze the structural differences of these 2 enzymes that may explain their different behaviors and properties.
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18
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Klevstig MJ, Markova I, Burianova J, Kazdova L, Pravenec M, Novakova O, Novak F. Role of FAT/CD36 in novel PKC isoform activation in heart of spontaneously hypertensive rats. Mol Cell Biochem 2011; 357:163-9. [PMID: 21625957 DOI: 10.1007/s11010-011-0886-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 05/17/2011] [Indexed: 12/20/2022]
Abstract
Disruption to the sensitive balance of long-chain fatty acids and glucose in the heart could cause cardiovascular diseases. Searching for a possible role of novel protein kinase C (nPKC) in heart with disrupted energy balance, we compared the insulin-resistant spontaneously hypertensive rats (SHR), which carry a nonfunctional variant of the fatty acid transporter FAT/CD36, with the less insulin-resistant congenic strain SHR-4 that is genetically identical except for a segment on chromosome 4 including a wild-type gene for a functional FAT/CD36. We analyzed expression of the nPKC-δ and -ε isoforms plus triacylglycerols (TAG) content in the myocardium of both FAT/CD36 strains and after a high sucrose diet (HSD). Two weeks before killing, males of both strains were randomly divided into two groups and fed either a standard laboratory chow or an HSD. PKC was determined by Western blotting in particulate and cytosolic fractions from left ventricles. The SHR-4 rats exhibited lower serum levels of insulin and free fatty acids than did SHR rats and higher amounts of PKC-ε in the heart particulate fraction. HSD caused accumulation of heart TAG in SHR but not in SHR-4. HSD increased PKC-δ and decreased PKC-ε expression in particulate fraction from left ventricles of SHR-4 while having no effects in SHR. These results demonstrate that reduced insulin resistance in SHR-4 rats with wild-type FAT/CD36 is associated with the insulin signaling pathway involving nPKCs.
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Affiliation(s)
- Martina J Klevstig
- Department of Cell Biology, Charles University, Vinicna 7, 12843 Prague, Czech Republic
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19
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Chechi K, Herzberg GR, Cheema SK. Maternal dietary fat intake during gestation and lactation alters tissue fatty acid composition in the adult offspring of C57Bl/6 mice. Prostaglandins Leukot Essent Fatty Acids 2010; 83:97-104. [PMID: 20688254 DOI: 10.1016/j.plefa.2010.06.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2009] [Accepted: 06/03/2010] [Indexed: 02/06/2023]
Abstract
We investigated the effects of maternal dietary fat intake during gestation and lactation on the tissue fatty acid composition of the adult offspring. Female C57Bl/6 mice were fed high fat diets enriched with lard or safflower oil or chow during mating, gestation and lactation. The offspring obtained from each group of mothers were continued on diets rich in lard, safflower oil or chow post-weaning until 11 weeks of age. Livers and hearts were collected for fatty acid analysis. A maternal diet rich in safflower oil was associated with enrichment of hepatic tissue with n-3 polyunsaturated fatty acids in the offspring fed chow post-weaning compared to the offspring fed chow throughout. However, a continuous exposure to a safflower oil- as well as lard-rich diet during the pre- and post-weaning time periods was associated with reduced content of docosahexaenoic acid in both liver and heart tissues compared to the offspring fed chow throughout. In conclusion, this study demonstrated lasting effects of maternal dietary fat intake, as well as an interaction between pre- and post-weaning diets, on the tissue fatty composition in adult offspring.
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Affiliation(s)
- Kanta Chechi
- Department of Biochemistry, Memorial University, St. John's, NL, Canada
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20
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Kwon SJ, Kim DH. Characterization of junctate-SERCA2a interaction in murine cardiomyocyte. Biochem Biophys Res Commun 2009; 390:1389-94. [PMID: 19896466 DOI: 10.1016/j.bbrc.2009.10.165] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Accepted: 10/31/2009] [Indexed: 02/02/2023]
Abstract
Junctate is a newly identified sarcoplasmic reticulum (SR) Ca(2+) binding protein, but its function in cardiac muscle has remained unclear. Our previous study showed that chronic over-expression of junctate in transgenic mice led to altered SR functions and development of severe hypertrophy. In this study, we identified the interaction of junctate with SERCA2a by co-immunoprecipitation and GST-pull-down assay. This interaction was inhibited by higher Ca(2+) concentration. Immunolocalization assays also showed that junctate and SERCA2a were co-localized in the SR of cardiomyocytes. Direct binding of the C-terminal region of junctate (amino acids 79-270) and luminal domain of SERCA2a (amino acids 70-89) was observed by deletion mutation experiments. Adenovirus-mediated transient over-expression of junctate in cardiomyocytes showed a reduced decay time of Ca(2+) transients and increased oxalate-supported SERCA2 Ca(2+) uptake, suggesting an increased activity of SERCA2a. Taken together, according to our data, junctate may play an important role in the regulation of SR Ca(2+) cycling through the interaction with SERCA2a in the murine heart.
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Affiliation(s)
- Soon-Jae Kwon
- Department of Life Science and Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
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21
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Kooij V, Boontje N, Zaremba R, Jaquet K, dos Remedios C, Stienen GJM, van der Velden J. Protein kinase C alpha and epsilon phosphorylation of troponin and myosin binding protein C reduce Ca2+ sensitivity in human myocardium. Basic Res Cardiol 2009; 105:289-300. [PMID: 19655190 PMCID: PMC2807945 DOI: 10.1007/s00395-009-0053-z] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Revised: 07/20/2009] [Accepted: 07/22/2009] [Indexed: 12/01/2022]
Abstract
Previous studies indicated that the increase in protein kinase C (PKC)-mediated myofilament protein phosphorylation observed in failing myocardium might be detrimental for contractile function. This study was designed to reveal and compare the effects of PKCα- and PKCε-mediated phosphorylation on myofilament function in human myocardium. Isometric force was measured at different [Ca2+] in single permeabilized cardiomyocytes from failing human left ventricular tissue. Activated PKCα and PKCε equally reduced Ca2+ sensitivity in failing cardiomyocytes (ΔpCa50 = 0.08 ± 0.01). Both PKC isoforms increased phosphorylation of troponin I- (cTnI) and myosin binding protein C (cMyBP-C) in failing cardiomyocytes. Subsequent incubation of failing cardiomyocytes with the catalytic subunit of protein kinase A (PKA) resulted in a further reduction in Ca2+ sensitivity, indicating that the effects of both PKC isoforms were not caused by cross-phosphorylation of PKA sites. Both isozymes showed no effects on maximal force and only PKCα resulted in a modest significant reduction in passive force. Effects of PKCα were only minor in donor cardiomyocytes, presumably because of already saturated cTnI and cMyBP-C phosphorylation levels. Donor tissue could therefore be used as a tool to reveal the functional effects of troponin T (cTnT) phosphorylation by PKCα. Massive dephosphorylation of cTnT with alkaline phosphatase increased Ca2+ sensitivity. Subsequently, PKCα treatment of donor cardiomyocytes reduced Ca2+ sensitivity (ΔpCa50 = 0.08 ± 0.02) and solely increased phosphorylation of cTnT, but did not affect maximal and passive force. PKCα- and PKCε-mediated phosphorylation of cMyBP-C and cTnI as well as cTnT decrease myofilament Ca2+ sensitivity and may thereby reduce contractility and enhance relaxation of human myocardium.
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Affiliation(s)
- Viola Kooij
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
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22
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Dai S, Hall DD, Hell JW. Supramolecular assemblies and localized regulation of voltage-gated ion channels. Physiol Rev 2009; 89:411-52. [PMID: 19342611 DOI: 10.1152/physrev.00029.2007] [Citation(s) in RCA: 281] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
This review addresses the localized regulation of voltage-gated ion channels by phosphorylation. Comprehensive data on channel regulation by associated protein kinases, phosphatases, and related regulatory proteins are mainly available for voltage-gated Ca2+ channels, which form the main focus of this review. Other voltage-gated ion channels and especially Kv7.1-3 (KCNQ1-3), the large- and small-conductance Ca2+-activated K+ channels BK and SK2, and the inward-rectifying K+ channels Kir3 have also been studied to quite some extent and will be included. Regulation of the L-type Ca2+ channel Cav1.2 by PKA has been studied most thoroughly as it underlies the cardiac fight-or-flight response. A prototypical Cav1.2 signaling complex containing the beta2 adrenergic receptor, the heterotrimeric G protein Gs, adenylyl cyclase, and PKA has been identified that supports highly localized via cAMP. The type 2 ryanodine receptor as well as AMPA- and NMDA-type glutamate receptors are in close proximity to Cav1.2 in cardiomyocytes and neurons, respectively, yet independently anchor PKA, CaMKII, and the serine/threonine phosphatases PP1, PP2A, and PP2B, as is discussed in detail. Descriptions of the structural and functional aspects of the interactions of PKA, PKC, CaMKII, Src, and various phosphatases with Cav1.2 will include comparisons with analogous interactions with other channels such as the ryanodine receptor or ionotropic glutamate receptors. Regulation of Na+ and K+ channel phosphorylation complexes will be discussed in separate papers. This review is thus intended for readers interested in ion channel regulation or in localization of kinases, phosphatases, and their upstream regulators.
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Affiliation(s)
- Shuiping Dai
- Department of Pharmacology, University of Iowa, Iowa City, IA 52242-1109, USA
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23
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van Rossum DB, Patterson RL. PKC and PLA2: probing the complexities of the calcium network. Cell Calcium 2009; 45:535-45. [PMID: 19345415 DOI: 10.1016/j.ceca.2009.02.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 02/24/2009] [Accepted: 02/26/2009] [Indexed: 11/15/2022]
Abstract
Lipid signaling and phosphorylation cascades are fundamental to calcium signaling networks. In this review, we will discuss the recent laboratory findings for the phospholipase A(2) (PLA(2))/protein kinase C (PKC) pathway within cellular calcium networks. The complexity and connectivity of these ubiquitous cellular signals make interpretation of experimental results extremely challenging. We present here computational methods which have been developed to conquer such complex data, and how they can be used to make models capable of accurately predicting cellular responses within multiple calcium signaling pathways. We propose that information obtained from network analysis and computational techniques provides a rich source of knowledge which can be directly translated to the laboratory benchtop.
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Affiliation(s)
- Damian B van Rossum
- Department of Biology, The Pennsylvania State University, PA, United States.
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24
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Adenosine triggers the nuclear translocation of protein kinase C epsilon in H9c2 cardiomyoblasts with the loss of phosphorylation at Ser729. J Cell Biochem 2009; 106:633-42. [DOI: 10.1002/jcb.22043] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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25
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Maturana AD, Wälchli S, Iwata M, Ryser S, Van Lint J, Hoshijima M, Schlegel W, Ikeda Y, Tanizawa K, Kuroda S. Enigma homolog 1 scaffolds protein kinase D1 to regulate the activity of the cardiac L-type voltage-gated calcium channel. Cardiovasc Res 2008; 78:458-65. [PMID: 18296710 DOI: 10.1093/cvr/cvn052] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
AIMS In cardiomyocytes, protein kinase D1 (PKD1) plays a central role in the response to stress signals. From a yeast two-hybrid assay, we have identified Enigma Homolog 1 (ENH1) as a new binding partner of PKD1. Since in neurons, ENH1, associated with protein kinase Cepsilon, was shown to modulate the activity of N-type calcium channels, and the pore-forming subunit of the cardiac L-type voltage-gated calcium channel, alpha1C, possesses a potential phosphorylation site for PKD1, we studied here a possible role of ENH1 and PKD1 in the regulation of the cardiac L-type voltage-gated calcium channel. METHODS AND RESULTS PKD1-interacting proteins were searched by yeast two-hybrid screening. In vivo protein interactions in cardiomyocytes isolated from heart ventricles of newborn rats were tested by co-immunoprecipitation. Small interfering RNA and a dominant negative mutant of PKD1 were delivered into cardiomyocytes by use of an adenovirus. Calcium currents were measured by the patch-clamp technique. Both ENH1 and PKD1 interact with alpha1C in cardiomyocytes. This interaction is increased upon stimulation. Silencing of ENH1 prevented the binding of PKD1 to alpha1C. Moreover, a dominant negative mutant of PKD1 or the silencing of ENH1 inhibited the alpha-adrenergic-induced increase of L-type calcium currents. CONCLUSION We found a new binding partner, ENH1, and a new target, alpha1C, for PKD1 in neonatal rat cardiomyocytes. We propose a model where ENH1 scaffolds PKD1 to alpha1C in order to form a signalling complex that regulates the activity of cardiac L-type voltage-gated Ca(2+) channels.
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MESH Headings
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Adenoviridae/genetics
- Adrenergic alpha-Agonists/pharmacology
- Animals
- Animals, Newborn
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Calcium Signaling/drug effects
- Cells, Cultured
- Genetic Vectors
- HeLa Cells
- Humans
- Immunoprecipitation
- LIM Domain Proteins
- Membrane Potentials
- Mutation
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/enzymology
- Patch-Clamp Techniques
- Phenylephrine/pharmacology
- Protein Binding
- Protein Kinase C
- Protein Kinases/genetics
- Protein Kinases/metabolism
- Protein Structure, Tertiary
- RNA Interference
- RNA, Small Interfering/metabolism
- Rabbits
- Rats
- Two-Hybrid System Techniques
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Affiliation(s)
- Andrés D Maturana
- Department of Structural Molecular Biology, Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan.
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26
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Walker JW. Protein scaffolds, lipid domains and substrate recognition in protein kinase C function: implications for rational drug design. Handb Exp Pharmacol 2008:185-203. [PMID: 18491053 DOI: 10.1007/978-3-540-72843-6_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Protein kinase C (PKC) represents a family of lipid-regulated protein kinases with ubiquitous expression throughout the animal kingdom. High fidelity in PKC phosphorylation of intended target substrates is crucial for normal cell and tissue function. Therefore, it is likely that multiple interdependent factors contribute to determining substrate specificity in vivo, including divalent cation binding, substrate recognition motifs, local lipid heterogeneity and protein scaffolds. This review provides an overview of targeting mechanisms for the three subclasses of PKC isoforms, conventional, novel and atypical, with an emphasis on how they bind to substrates, lipids/lipid microdomains and multifunctional protein scaffolds. The diversity of interactions between PKC isoforms and their immediate environment is extensive, suggesting that systems biology approaches including proteomics and network modeling may be important strategies for rational drug design in the future.
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Affiliation(s)
- J W Walker
- Department of Physiology, Director of Human Proteomics Program, University of Wisconsin, Madison, WI 53706, USA.
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27
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Singh P. Role of Annexin-II in GI cancers: interaction with gastrins/progastrins. Cancer Lett 2006; 252:19-35. [PMID: 17188424 PMCID: PMC1941619 DOI: 10.1016/j.canlet.2006.11.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Accepted: 11/06/2006] [Indexed: 12/27/2022]
Abstract
The role of the gastrin peptide hormones (G17, G34) and their precursors (progastrins, PG; gly-extended gastrin, G-gly), in gastrointestinal (GI) cancers has been extensively reviewed in recent years [W. Rengifo-Cam, P. Singh, Role of progastrins and gastrins and their receptors in GI and pancreatic cancers: targets for treatment, Curr. Pharm. Des. 10 (19) (2004) 2345-2358; M. Dufresne, C. Seva, D. Fourmy, Cholecystokinin and gastrin receptors, Physiol. Rev. 86 (3) (2006) 805-847; A. Ferrand, T.C. Wang, Gastrin and cancer: a review, Cancer Lett. 238 (1) (2006) 15-29]. A possible important role of progastrin peptides in colon carcinogenesis has become evident from experiments with transgenic mouse models [W. Rengifo-Cam, P. Singh, (2004); A. Ferrand, T.C. Wang, (2006)]. It is now known that growth stimulatory and co-carcinogenic effects of gastrin/PG peptides are mediated by both proliferative and anti-apoptotic effects of the peptides on target cells [H. Wu, G.N. Rao, B. Dai, P. Singh, Autocrine gastrins in colon cancer cells Up-regulate cytochrome c oxidase Vb and down-regulate efflux of cytochrome c and activation of caspase-3, J. Biol. Chem. 275 (42) (2000) 32491-32498; H. Wu, A. Owlia, P. Singh, Precursor peptide progastrin(1-80) reduces apoptosis of intestinal epithelial cells and upregulates cytochrome c oxidase Vb levels and synthesis of ATP, Am. J. Physiol. Gastrointest. Liver Physiol. 285 (6) (2003) G1097-G1110]. Several receptor subtypes have been described that mediate growth effects of gastrin peptides [W. Rengifo-Cam, P. Singh (2004); M. Dufresne, C. Seva, D. Fourmy, (2006)]. Recently, we identified Annexin II as a high affinity binding protein for gastrin/PG peptides [P. Singh, H. Wu, C. Clark, A. Owlia, Annexin II binds progastrin and gastrin-like peptides, and mediates growth factor effects of autocrine and exogenous gastrins on colon cancer and intestinal epithelial cells, Oncogene (2006), doi:10.1038/sj.onc.1209798]. Importantly, the expression of Annexin II was required for mediating growth stimulatory effects of gastrin and PG peptides on intestinal epithelial and colon cancer cells [P. Singh, H. Wu, C. Clark, A. Owlia, Annexin II binds progastrin and gastrin-like peptides, and mediates growth factor effects of autocrine and exogenous gastrins on colon cancer and intestinal epithelial cells, Oncogene (2006), doi:10.1038/sj.onc.1209798], suggesting that Annexin-II may represent the elusive novel receptor for gastrin/PG peptides. The importance of this finding in relation to the structure and function of Annexin-II, especially in GI cancers, is described below. Since this surprising finding represents a new front in our understanding of the mechanisms involved in mediating growth effects of gastrin/PG peptides in GI cancers, our current understanding of the role of Annexin-II in proliferation and metastasis of cancer cells is additionally reviewed.
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Affiliation(s)
- Pomila Singh
- Department of Neuroscience and Cell Biology, 10.104 Medical Research Building, Route 1043, University of Texas Medical Branch, 301University Blvd., Mail Route 1043, Galveston, TX 77555-1043, USA.
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Du J, Zhang C, Liu J, Sidky C, Huang XP. A point mutation (R192H) in the C-terminus of human cardiac troponin I causes diastolic dysfunction in transgenic mice. Arch Biochem Biophys 2006; 456:143-50. [PMID: 17027633 DOI: 10.1016/j.abb.2006.08.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Revised: 08/11/2006] [Accepted: 08/12/2006] [Indexed: 12/01/2022]
Abstract
Cardiac troponin I (cTnI) mutations have been linked to the development of restrictive cardiomyopathy (RCM) in human patients. We modeled one mutation in human cTnI C-terminus, arginine192-->histidine (R192H) by cardiac specific expression of the mutated protein (cTnI(193His) in mouse sequence) in transgenic mice. Heart tissue sections revealed neither significant hypertrophy nor ventricular dilation in cTnI(193His) mice. The main functional alteration detected in cTnI(193His) mice by ultrasound cardiac imaging examinations was impaired cardiac relaxation manifested by a decreased left ventricular end diastolic dimension (LVEDD) and an increased end diastolic dimension in both atria. The cardiac ejection fraction (EF) was not significant changed in 6- to 8-week-old cTnI(193His) mice, however, the EF was significantly decreased in cTnI(193His) mice at age of 11 months. These data indicate that individual genetic conditions and environmental factors participate together in the development of the cTnI mutation based-cardiac muscle disorders. This mouse model provides us with a tool to further investigate the pathophysiology and the development of RCM.
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Affiliation(s)
- J Du
- Department of Biomedical Science and Center for Molecular Biology and Biotechnology, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA
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Shah SA, Mahmud N, Mftah M, Roche HM, Kelleher D. Chronic but not acute conjugated linoleic acid treatment inhibits deoxycholic acid-induced protein kinase C and nuclear factor-kappaB activation in human colorectal cancer cells. Eur J Cancer Prev 2006; 15:125-33. [PMID: 16523009 DOI: 10.1097/01.cej.0000195708.72072.42] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Conjugated linoleic acid (CLA) has anti-carcinogenic effects in a variety of cancers including colon cancer. Secondary bile acids on the other hand are known as tumour promoters in colon cancer with effects on protein kinase C (PKC) and nuclear factor kappa B (NF-kappaB) signalling pathways. The aim of this study was to examine acute and chronic, isomer-specific effects of CLA on bile salt-induced PKC and NF-kappaB signal transduction in human colon cancer cells. HCT116 cells were treated with 100 mumol/l and 50 mumol/l cis-9,trans-11-CLA and trans-10,cis-12-CLA for 24 h and 14 days, respectively. The cells were then transfected with DNA coding for PKC beta1-EGFP (enhanced green fluorescent protein), PKC delta-EGFP or PKC zeta-EGFP fusion protein and activated with deoxycholic acid (DCA), phorbol myristate acetate (PMA) or C2-ceramide. PKC translocation was observed using real-time photomicroscopy and fluorescent microscopy and NF-kappaB analyses by gel shift assays. Chronic c-9,t-11-CLA and t-10,c-12-CLA treatment inhibited DCA-induced PKC beta1 and PKC delta translocation and also inhibited NF-kappaB activation. Acute CLA treatment had no effect on PKC or NF-kappaB activation. In conclusion this study indicates that chronic CLA treatment inhibits DCA-induced PKC and NF-kappaB activation in colon cancer cells. These data suggest mechanisms by which CLA may influence the course of colonic cancer.
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Grimm M, Mahnecke N, Soja F, El-Armouche A, Haas P, Treede H, Reichenspurner H, Eschenhagen T. The MLCK-mediated alpha1-adrenergic inotropic effect in atrial myocardium is negatively modulated by PKCepsilon signaling. Br J Pharmacol 2006; 148:991-1000. [PMID: 16783412 PMCID: PMC1751924 DOI: 10.1038/sj.bjp.0706803] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The present study examined the role of myosin light chain kinase (MLCK), PKC isozymes, and inositol 1,4,5-trisphosphate (IP(3)) receptor in the positive inotropic effect of alpha(1)-adrenergic stimulation in atrial myocardium. We measured inotropic effects of phenylephrine (0.3-300 microM) in isolated left atrial preparations (1 Hz, 37 degrees C, 1.8 mM Ca(2+), 0.3 microM nadolol) from male 8-week FVB mice (n=200). Phenylephrine concentration-dependently increased force of contraction from 1.5+/-0.1 to 2.8+/-0.1 mN (mean+/-s.e.m., n=42), which was associated with increased MLC-2a phosphorylation at serine 21 and 22 by 67% and translocation of PKCepsilon but not PKCalpha to membrane (+30%) and myofilament (+50%) fractions.MLCK inhibition using ML-7 or wortmannin right-shifted the concentration-response curve of phenylephrine, reducing its inotropic effect at 10 microM by 73% and 81%, respectively. The compound KIE1-1 (500 nM), an intracellularly acting PKCepsilon translocation inhibitor peptide, prevented PKCepsilon translocation and augmented the maximal inotropic effect of phenylephrine by 40%. In contrast, inhibition of Ca(2+)-dependent PKC translocation (KIC1-1, 500 nM) had no effect. Chelerythrine, a PKC inhibitor, decreased basal force without changing the inotropic effect of phenylephrine. The IP(3) receptor blocker 2-APB (2 and 20 microM) concentration-dependently decreased basal force, but did not affect the concentration-response curve of phenylephrine. These results indicate that activation of MLCK is required for the positive inotropic effect of alpha(1)-adrenergic stimulation, that the Ca(2+)-independent PKCepsilon negatively modulates this effect, and that PKCalpha and IP(3) receptor activation is not involved.
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Affiliation(s)
- Michael Grimm
- Institute of Experimental and Clinical Pharmacology and Toxicology, University Medical Center, Hamburg, Germany
| | - Nina Mahnecke
- Institute of Experimental and Clinical Pharmacology and Toxicology, University Medical Center, Hamburg, Germany
| | - Friederike Soja
- Institute of Experimental and Clinical Pharmacology and Toxicology, University Medical Center, Hamburg, Germany
| | - Ali El-Armouche
- Institute of Experimental and Clinical Pharmacology and Toxicology, University Medical Center, Hamburg, Germany
| | - Pascal Haas
- Institute of Experimental and Clinical Pharmacology and Toxicology, University Medical Center, Hamburg, Germany
| | - Hendrik Treede
- Department of Cardiovascular Surgery, University Medical Center, Hamburg, Germany
| | | | - Thomas Eschenhagen
- Institute of Experimental and Clinical Pharmacology and Toxicology, University Medical Center, Hamburg, Germany
- Author for correspondence:
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Hoshijima M. Mechanical stress-strain sensors embedded in cardiac cytoskeleton: Z disk, titin, and associated structures. Am J Physiol Heart Circ Physiol 2006; 290:H1313-25. [PMID: 16537787 PMCID: PMC3241960 DOI: 10.1152/ajpheart.00816.2005] [Citation(s) in RCA: 193] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cardiac muscle is equipped with intricate intrinsic mechanisms to regulate adaptive remodeling. Recent and extensive experimental findings powered by novel strategies for screening protein-protein interactions, improved imaging technologies, and versatile transgenic mouse methodologies reveal that Z disks and titin filaments possess unexpectedly complicated sensory and modulatory mechanisms for signal reception and transduction. These mechanisms employ molecules such as muscle-enriched LIM domain proteins, PDZ-LIM domain proteins, myozenin gene family members, titin-associated ankyrin repeat family proteins, and muscle-specific ring finger proteins, which have been identified as potential molecular sensor components. Moreover, classic transmembrane signaling processes, including mitogen-activated kinase, protein kinase C, and calcium signaling, also involve novel interactions with the Z disk/titin network. This compartmentalization of signaling complexes permits alteration of receptor-dependent transcriptional regulation by direct sensing of intrinsic stress. Newly identified mechanical stress sensors are not limited to Z-disk region and to I-band and M-band regions of titin but are also embedded in muscle-specific membrane systems such as the costamere, intercalated disks, and caveolae-like microdomains. This review summarizes current knowledge of this rapidly developing area with focus on how the heart adjusts physiological remodeling process to meet with mechanical demands and how this process fails in cardiac pathologies.
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Affiliation(s)
- Masahiko Hoshijima
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0734, USA.
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32
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Frank D, Kuhn C, Katus HA, Frey N. The sarcomeric Z-disc: a nodal point in signalling and disease. J Mol Med (Berl) 2006; 84:446-68. [PMID: 16416311 DOI: 10.1007/s00109-005-0033-1] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Accepted: 11/23/2005] [Indexed: 12/11/2022]
Abstract
The perception of the Z-disc in striated muscle has undergone significant changes in the past decade. Traditionally, the Z-disc has been viewed as a passive constituent of the sarcomere, which is important only for the cross-linking of thin filaments and transmission of force generated by the myofilaments. The recent discovery of multiple novel molecular components, however, has shed light on an emerging role for the Z-disc in signal transduction in both cardiac and skeletal muscles. Strikingly, mutations in several Z-disc proteins have been shown to cause cardiomyopathies and/or muscular dystrophies. In addition, the elusive cardiac stretch receptor appears to localize to the Z-disc. Various signalling molecules have been shown to interact with Z-disc proteins, several of which shuttle between the Z-disc and other cellular compartments such as the nucleus, underlining the dynamic nature of Z-disc-dependent signalling. In this review, we provide a systematic view on the currently known Z-disc components and the functional significance of the Z-disc as an interface between biomechanical sensing and signalling in cardiac and skeletal muscle functions and diseases.
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Affiliation(s)
- Derk Frank
- Department of Internal Medicine III, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
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Abstract
Mechanotransduction refers to the cellular mechanisms by which load-bearing cells sense physical forces, transduce the forces into biochemical signals, and generate appropriate responses leading to alterations in cellular structure and function. This process affects the beat-to-beat regulation of cardiac performance but also affects the proliferation, differentiation, growth, and survival of the cellular components that comprise the human myocardium. This review focuses on the experimental evidence indicating that the costamere and its structurally related structure the focal adhesion complex are critical cytoskeletal elements involved in cardiomyocyte mechanotransduction. Biochemical signals originating from the extracellular matrix-integrin-costameric protein complex share many common features with those signals generated by growth factor receptors. The roles of key regulatory kinases and other muscle-specific proteins involved in mechanotransduction and growth factor signaling are discussed, and issues requiring further study in this field are outlined.
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Affiliation(s)
- Allen M Samarel
- Cardiovascular Institute, Loyola Univ. Medical Center, Bldg. 110, Rm. 5222, 2160 South First Ave., Maywood, IL 60153, USA.
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34
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Abstract
The Z-line represents a critical link between the transverse tubule network and cytoskeleton of cardiac cells with a role in anchoring structural proteins, ion channels, and signaling molecules. Protein kinase C-epsilon (PKC-epsilon) regulates cardiac excitability, cardioprotection, and growth, possibly as a consequence of translocation to the Z-line/T tubule region. To investigate the mechanism of PKC-epsilon translocation, fragments of its NH2-terminal 144-amino acid variable domain, epsilonV1, were fused with green fluorescent protein and evaluated by quantitative Fourier image analysis of decorated myocytes. Deletion of 23 amino acids from the NH2-terminus of epsilonV1, including an EAVSLKPT motif important for binding to a receptor for activated C kinase (RACK2), reduced but did not abolish Z-line binding. Further deletions of up to 84 amino acids from the NH2-terminus of epsilonV1 also did not prevent Z-line decoration. However, deletions of residues 85-144 from the COOH-terminus strongly reduced Z-line binding. COOH-terminal deletions caused 2.5-fold greater loss of binding energy (deltadeltaG) than did NH2-terminal deletions. Synthetic peptides derived from these regions modulated epsilonV1 binding and cardiac myocyte function, but also revealed considerable heterogeneity within populations of adult cardiac myocytes. The COOH-terminal subdomain important for Z-line anchoring maps to a surface in the epsilonV1 crystal structure that complements the eight-amino acid RACK2 binding site and two previously identified membrane docking motifs. PKC-epsilon anchoring at the cardiac Z-line/T tubule appears to rely on multiple points of contact probably involving protein-lipid and protein-protein interactions.
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Affiliation(s)
- Seth L Robia
- Dept. of Physiology, University of Wisconsin, Madison, WI 53706, USA
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35
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Montgomery DE, Rundell VLM, Goldspink PH, Urboniene D, Geenen DL, de Tombe PP, Buttrick PM. Protein kinase C epsilon induces systolic cardiac failure marked by exhausted inotropic reserve and intact Frank-Starling mechanism. Am J Physiol Heart Circ Physiol 2005; 289:H1881-8. [PMID: 15951344 DOI: 10.1152/ajpheart.00454.2005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myofilament dysfunction is a common point of convergence for many forms of heart failure. Recently, we showed that cardiac overexpression of PKC epsilon initially depresses myofilament activity and then leads to a progression of changes characteristic of human heart failure. Here, we examined the effects of PKC epsilon on contractile reserve, Starling mechanism, and myofilament activation in this model of end-stage dilated cardiomyopathy. Pressure-volume loop analysis and echocardiography showed that the PKC epsilon mice have markedly compromised systolic function and increased end-diastolic volumes. Dobutamine challenge resulted in a small increase in contractility in PKC epsilon mice but failed to enhance cardiac output. The PKC epsilon mice showed a normal length-dependent tension development in skinned cardiac muscle preparations, although Frank-Starling mechanism appeared to be compromised in the intact animal. Simultaneous measurement of tension and ATPase demonstrated that the maximum tension and ATPase were markedly lower in the PKC epsilon mice at any length or Ca2+ concentration. However, the tension cost was also lower indicating less energy expenditure. We conclude 1) that prolonged overexpression of PKC epsilon ultimately leads to a dilated cardiomyopathy marked by exhausted contractile reserve, 2) that PKC epsilon does not compromise the Frank-Starling mechanism at the myofilament level, and 3) that the Starling curve excursion is limited by the inotropic state of the heart. These results reflect the significance of the primary myofilament contractilopathy induced by phosphorylation and imply a role for PKC epsilon-mediated phosphorylation in myofilament physiology and the pathophysiology of decompensated cardiac failure.
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Affiliation(s)
- David E Montgomery
- Department of Medicine, Section of Cardiology, Univ. of Illinois at Chicago, College of Medicine, Chicago, IL 60612, USA
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Jia Y, Akerman S, Huang X. Myofibril MgATPase activities and energy metabolism in cardiomyopathic mice with diastolic dysfunction. J Biomed Sci 2005; 11:450-6. [PMID: 15153779 DOI: 10.1007/bf02256093] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2003] [Accepted: 01/08/2004] [Indexed: 10/25/2022] Open
Abstract
To study the genomic physiology of cardiac myofibril proteins in the heart, we have successfully created a cardiac troponin I (cTnI; a myofibril protein) gene knockout mouse model using gene targeting techniques. The phenotype of the cTnI gene knockout mouse is a cardiomyopathy with diastolic dysfunction resulting in sudden death in neonates. In the present studies, energy metabolism was analyzed in myocardial cells from cTnI-null hearts. Myofibril MgATPase activities were determined in myocardial cells from either wild-type or cTnI mutant mouse hearts. Furthermore, the quantity and quality of the mitochondria in wild-type and cTnI mutant animals were counted and analyzed. Our results demonstrate that damaged relaxation and increased Ca(2+)-independent force production in cTnI-null hearts is in part related to the increased myofibril MgATPase activities accompanied by an increase in mitochondria quantity and mitochondrial ATPase activities. These data indicate that cardiomyopathies with diastolic dysfunction are different from cardiomyopathies caused by systolic dysfunction. The former involves the damage of cardiac relaxation due to increased MgATPase activities and increased Ca(2+)-independent force production inside of myofilaments, while the latter involves the damage of systolic contraction due to decreased MgATPase activities and decreased force production.
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Affiliation(s)
- Yuanyuan Jia
- Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL 33431, USA
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37
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Iwata M, Maturana A, Hoshijima M, Tatematsu K, Okajima T, Vandenheede JR, Van Lint J, Tanizawa K, Kuroda S. PKCepsilon-PKD1 signaling complex at Z-discs plays a pivotal role in the cardiac hypertrophy induced by G-protein coupling receptor agonists. Biochem Biophys Res Commun 2005; 327:1105-13. [PMID: 15652511 PMCID: PMC3224855 DOI: 10.1016/j.bbrc.2004.12.128] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2004] [Indexed: 11/17/2022]
Abstract
Cardiac hypertrophy is triggered in response to mechanical stress and various neurohumoral factors, such as G-protein coupling receptor (GPCR) and gp130 cytokine receptor agonists. Recent studies have suggested cardiac Z-disc plays a pivotal role to regulate these cellular responses. Here, we demonstrate stimulations with GPCR agonists (norepinephrine, angiotensin II, and endothelin 1) and phorbol ester activated and translocated protein kinase D1 (PKD1) to the Z-discs in neonatal rat cardiomyocytes in a protein kinase C (PKC)-dependent manner, whereas gp130 agonist did not. Especially, upon the alpha-adrenergic receptor agonist stimulations, following the PKCepsilon-PKD1 complex formation, PKCepsilon-dependent activation of PKD1 was essential to induce hypertrophic responses. Constitutively active mutant of either PKD1 or PKCepsilon also induced cardiac hypertrophy ex vivo. Taken together, the PKCepsilon-PKD1 complex at Z-discs could play a pivotal role in the cardiac hypertrophy induced by GPCR agonists, at least alpha-adrenergic receptor agonist.
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Affiliation(s)
- Miki Iwata
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Andrés Maturana
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Masahiko Hoshijima
- Department of Medicine, Institute of Molecular Medicine, University of California San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Kenji Tatematsu
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Toshihide Okajima
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Jackie R. Vandenheede
- Afdeling Biochemie, Faculteit Geneeskunde, Campus Gasthisberg, Katholieke Universiteit Leuven, 49 Herestraat, Leuven B-3000, Belgium
| | - Johan Van Lint
- Afdeling Biochemie, Faculteit Geneeskunde, Campus Gasthisberg, Katholieke Universiteit Leuven, 49 Herestraat, Leuven B-3000, Belgium
| | - Katsuyuki Tanizawa
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Shun'ichi Kuroda
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
- Corresponding author. Fax: +81 6 6879 8462. (S. Kuroda)
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Riedel B, Jia Y, Du J, Akerman S, Huang X. Thyroid hormone inhibits slow skeletal TnI expression in cardiac TnI-null myocardial cells. Tissue Cell 2005; 37:47-51. [PMID: 15695175 DOI: 10.1016/j.tice.2004.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2004] [Revised: 09/15/2004] [Accepted: 10/13/2004] [Indexed: 11/17/2022]
Abstract
A cardiac troponin I (cTnI) gene knockout mouse model has been created and the phenotype of the cTnI null mice is an acute heart failure resulting from the deficiency of TnI and a diastolic dysfunction. Two isoforms of TnI (the fetal form ssTnI and the adult form cTnI) are mainly expressed in the heart under a developmentally regulated program. In our previous studies, we demonstrated that thyroid hormone could alter the time course of ssTnI gene expression in the heart. In the present study, we have successfully cultured neonatal cardiac myocytes from wild type and cTnI null mouse hearts. The ssTnI gene expression pattern has been investigated in these cells. By using Western blotting assays, a TnI isoform switching has been observed in the wild type cardiac myocytes. The pattern of TnI isoform switching is very similar to that of in vivo study we reported previously. In cTnI null cardiac myocytes cultured from day 1 to day 7, there is a continuous decline in ssTnI concentration in the cells. The time course of ssTnI decline in cTnI null cells is similar to that of wild type cardiac myocytes, suggesting that there is no significant compensation of ssTnI gene expression for the absence of the cTnI. This observation is different from what we found previously at a whole heart level. In addition, when thyroid hormone T3 (20 ng/ml) is added to cultured cTnI null cardiac myocytes, the decline of ssTnI concentration occurs earlier. This is inconsistent with our observations from previous in vivo studies. The data demonstrate that thyroid hormone can alter the time course of ssTnI gene expression in cultured cardiac myocytes and TnI gene regulation is also controlled by some unknown programmed events inside of cardiac myocytes.
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Affiliation(s)
- Beth Riedel
- Department of Biomedical Science and Center for Molecular Biology and Biotechnology, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA
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39
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Xu TR, Rumsby MG. Phorbol ester-induced translocation of PKC epsilon to the nucleus in fibroblasts: identification of nuclear PKC epsilon-associating proteins. FEBS Lett 2004; 570:20-4. [PMID: 15251432 DOI: 10.1016/j.febslet.2004.05.080] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2004] [Revised: 05/21/2004] [Accepted: 05/27/2004] [Indexed: 10/26/2022]
Abstract
We show that phorbol ester treatment of NIH 3T3 fibroblasts induces rapid translocation of PKC from a perinuclear site to the nucleus, extending findings in PC12 and NG108-15 cells and in myocytes. We have immunoprecipitated the PKC from nuclei isolated from phorbol ester-treated fibroblasts and identified six proteins which associate with nuclear PKC. These have been characterised as matrin 3, transferrin, Rac GTPase activating protein 1, vimentin, beta-actin and annexin II by MALDI-TOF-MS. We have confirmed that these proteins associate with PKC by gel overlay and/or dot blotting assays. The role of these PKC-associating proteins in the nucleus and their interaction with PKC are considered.
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Affiliation(s)
- Tian-Rui Xu
- Department of Biology, University of York, York YO10 5DD, UK
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40
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Lanni C, Mazzucchelli M, Porrello E, Govoni S, Racchi M. Differential involvement of protein kinase C alpha and epsilon in the regulated secretion of soluble amyloid precursor protein. ACTA ACUST UNITED AC 2004; 271:3068-75. [PMID: 15233804 DOI: 10.1111/j.1432-1033.2004.04240.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We investigated the differential role of protein kinase C (PKC) isoforms in the regulated proteolytic release of soluble amyloid precursor protein (sAPPalpha) in SH-SY5Y neuroblastoma cells. We used cells stably transfected with cDNAs encoding either PKCalpha or PKCepsilon in the antisense orientation, producing a reduction of the expression of PKCalpha and PKCepsilon, respectively. Reduced expression of PKCalpha and/or PKCepsilon did not modify the response of the kinase to phorbol ester stimulation, demonstrating translocation of the respective isoforms from the cytosolic fraction to specific intracellular compartments with an interesting differential localization of PKCalpha to the plasma membrane and PKCepsilon to Golgi-like structures. Reduced expression of PKCalpha significantly impaired the secretion of sAPPalpha induced by treatment with phorbol esters. Treatment of PKCalpha-deficient cells with carbachol induced a significant release of sAPPalpha. These results suggest that the involvement of PKCalpha in carbachol-induced sAPPalpha release is negligible. The response to carbachol is instead completely blocked in PKCepsilon-deficient cells suggesting the importance of PKCepsilon in coupling cholinergic receptors with APP metabolism.
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Affiliation(s)
- Cristina Lanni
- Department of Experimental and Applied Pharmacology, Centre of Excellence in Applied Biology and School of Pharmacy, University of Pavia, Viale Taramelli 14, 27100 Pavia, Italy
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41
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Miyazaki K, Komatsu S, Ikebe M, Fenton RA, Dobson JG. Protein kinase Cepsilon and the antiadrenergic action of adenosine in rat ventricular myocytes. Am J Physiol Heart Circ Physiol 2004; 287:H1721-9. [PMID: 15205171 DOI: 10.1152/ajpheart.00224.2004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adenosine-induced antiadrenergic effects in the heart are mediated by adenosine A(1) receptors (A(1)R). The role of PKCepsilon in the antiadrenergic action of adenosine was explored with adult rat ventricular myocytes in which PKCepsilon was overexpressed. Myocytes were transfected with a pEGFP-N1 vector in the presence or absence of a PKCepsilon construct and compared with normal myocytes. The extent of myocyte shortening elicited by electrical stimulation of quiescent normal and transfected myocytes was recorded with video imaging. PKCepsilon was found localized primarily in transverse tubules. The A(1)R agonist chlorocyclopentyladenosine (CCPA) at 1 microM rendered an enhanced localization of PKCepsilon in the t-tubular system. The beta-adrenergic agonist isoproterenol (Iso; 0.4 microM) elicited a 29-36% increase in myocyte shortening in all three groups. Although CCPA significantly reduced the Iso-produced increase in shortening in all three groups, the reduction caused by CCPA was greatest with PKCepsilon overexpression. The CCPA reduction of the Iso-elicited shortening was eliminated in the presence of a PKCepsilon inhibitory peptide. These results suggest that the translocation of PKCepsilon to the t-tubular system plays an important role in A(1)R-mediated antiadrenergic actions in the heart.
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Affiliation(s)
- Koji Miyazaki
- Dept. of Physiology, S4-242, University of Massachusetts Medical School, 55 Lake Avenue N., Worcester, MA 01655, USA
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Pyle WG, Solaro RJ. At the crossroads of myocardial signaling: the role of Z-discs in intracellular signaling and cardiac function. Circ Res 2004; 94:296-305. [PMID: 14976140 DOI: 10.1161/01.res.0000116143.74830.a9] [Citation(s) in RCA: 178] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Understanding the molecular interactions among components of cardiac Z-discs and their role in signaling has become pivotal in explaining long- and short-term regulation of cardiac function. In striated muscle, the ends of the thin filaments from opposing sarcomeres overlap and are cross-linked by an elaborate array of proteins to form a highly ordered, yet dynamic network that is the Z-disc. We review here a current picture of the function and structure of the Z-disc of mammalian cardiac myocytes. We emphasize provocative findings that advance new theories about the place of cardiac Z-discs in myocardial intra- and intercellular signaling in myocardial physiology and pathology. Relatively new approaches, especially yeast two-hybrid screens, immunoprecipitation, and pull down assays, as well as immunohistochemical analysis have significantly altered previous views of the protein content of the Z-disc. These studies have generally defined domain structure and binding partners for Z-disc proteins, but the functional significance of the binding network and of the domains in cardiac cell biology remains an unfolding story. Yet, even at the present level of understanding, perceptions of potential functions of the Z-disc proteins are expanding greatly and leading to new and exciting experimental approaches toward mechanistic understanding. The theme of the following discussion of these Z-disc proteins centers on their potential to function not only as a physical anchor for myofilament and cytoskeletal proteins, but also as a pivot for reception, transduction, and transmission of mechanical and biochemical signals.
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Affiliation(s)
- W Glen Pyle
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada
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Huang X, Walker JW. Myofilament anchoring of protein kinase C-epsilon in cardiac myocytes. J Cell Sci 2004; 117:1971-8. [PMID: 15039458 DOI: 10.1242/jcs.01044] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Regulatory proteins on muscle filaments are substrates for protein kinase C (PKC) but mechanisms underlying activation and translocation of PKC to this non-membrane compartment are poorly understood. Here we demonstrate that the epsilon isoform of PKC (ϵ-PKC) activated by arachidonic acid (AA) binds reversibly to cardiac myofibrils with an EC50 of 86 nM. Binding occurred near the Z-lines giving rise to a striated staining pattern. The delta isoform of PKC (δ-PKC) did not bind to cardiac myofibrils regardless of the activator used, and the alpha isoform (α-PKC) bound only under strong activating conditions. Three established PKC anchoring proteins, filamentous actin (F-actin), the LIM domain protein Cypher-1, and the coatamer protein β′-COP were each tested for their involvement in cytoskeletal anchoring. F-actin bound ϵ-PKC selectively over δ-PKC and α-PKC, but this interaction was readily distinguishable from cardiac myofilament binding in two ways. First, the F-actin/ϵ-PKC interaction was independent of PKC activation, and second, the synthetic hexapeptide LKKQET derived from the C1 region of ϵ-PKC effectively blocked ϵ-PKC binding to F-actin, but was without effect on its binding to cardiac myofilaments. Involvement of Cypher-1 was ruled out on the basis of its absence from detergent-skinned myofibrils that bound ϵ-PKC, despite its presence in intact cardiac myocytes. The ϵ-PKC translocation inhibitor peptide EAVSLKPT reduced activated ϵ-PKC binding to cardiac myofibrils in a concentration dependent manner, suggesting that a RACK2 or a similar protein plays a role in ϵ-PKC anchoring in cardiac myofilaments.
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Affiliation(s)
- Xupei Huang
- Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL 33431, USA.
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Robu VG, Pfeiffer ES, Robia SL, Balijepalli RC, Pi Y, Kamp TJ, Walker JW. Localization of functional endothelin receptor signaling complexes in cardiac transverse tubules. J Biol Chem 2003; 278:48154-61. [PMID: 12972433 DOI: 10.1074/jbc.m304396200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Endothelin-1 (ET-1) is an autocrine factor in the mammalian heart important in enhancing cardiac performance, protecting against myocardial ischemia, and initiating the development of cardiac hypertrophy. The ETA receptor is a seven-transmembrane G-protein-coupled receptor whose precise subcellular localization in cardiac muscle is unknown. Here we used fluorescein ET-1 and 125I-ET-1 to provide evidence for ET-1 receptors in cardiac transverse tubules (T-tubules). Moreover, the ETA receptor and downstream effector phospholipase C-beta 1 were co-localized within T-tubules using standard immunofluorescence techniques, and protein kinase C (PKC)-epsilon-enhanced green fluorescent protein bound reversibly to T-tubules upon activation. Localized photorelease of diacylglycerol further suggested compartmentation of PKC signaling, with release at the myocyte "surface" mimicking the negative inotropic effects of bath-applied PKC activators and "deep" release mimicking the positive inotropic effect of ET-1. The functional significance of T-tubular ET-1 receptors was further tested by rendering the T-tubule lumen inaccessible to bath-applied ET-1. Such "detubulated" cardiac myocytes showed no positive inotropic response to 20 nM ET-1, despite retaining both a nearly normal twitch response to field stimulation and a robust positive inotropic response to 20 nm isoproterenol. We propose that ET-1 enhances myocyte contractility by activating ETA receptor-phospholipase C-beta 1-PKC-epsilon signaling complexes preferentially localized in cardiac T-tubules. Compartmentation of ET-1 signaling complexes may explain the discordant effects of ET-1 versus bath applied PKC activators and may contribute to both the specificity and diversity of the cardiac actions of ET-1.
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Affiliation(s)
- Valentin G Robu
- Department of Physiology, University of Wisconsin, Madison, Wisconsin 53706, USA
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Pi Y, Zhang D, Kemnitz KR, Wang H, Walker JW. Protein kinase C and A sites on troponin I regulate myofilament Ca2+ sensitivity and ATPase activity in the mouse myocardium. J Physiol 2003; 552:845-57. [PMID: 12923217 PMCID: PMC2343448 DOI: 10.1113/jphysiol.2003.045260] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Cardiac troponin I (cTnI) is a phosphoprotein subunit of the troponin-tropomyosin complex that is thought to inhibit cardiac muscle contraction during diastole. To investigate the contributions of cTnI phosphorylation to cardiac regulation, transgenic mice were created with the phosphorylation sites of cTnI mutated to alanine. Activation of protein kinase C (PKC) by perfusion of hearts with phorbol-12-myristate-13-acetate (PMA) or endothelin-1 (ET-1) inhibited the maximum ATPase rate by up to 25 % and increased the Ca2+ sensitivity of ATPase activity and of isometric tension by up to 0.15 pCa units. PKC activation no longer altered cTnI phosphorylation, depressed ATPase rates or enhanced myofilament Ca2+ sensitivity in transgenic mice expressing cTnI that could not be phosphorylated on serines43/45 and threonine144 (PKC sites). Modest changes in myosin regulatory light chain phosphorylation occurred in all mouse lines, but increases in myofilament Ca2+ sensitivity required the presence of phosphorylatable cTnI. For comparison, the beta-adrenergic agonist isoproterenol caused a 38 % increase in maximum ATPase rate and a 0.12 pCa unit decrease in myofilament Ca2+ sensitivity. These beta-adrenergic effects were absent in transgenic mice expressing cTnI that could not be phosphorylated on serines23/24 (protein kinase A, PKA, sites). Overall, the results indicate that PKC and PKA exert opposing effects on actomyosin function by phosphorylating cTnI on distinct sites. A primary role of PKC phosphorylation of cTnI may be to reduce the requirements of the contractile apparatus for both Ca2+ and ATP, thereby promoting efficient ATP utilisation during contraction.
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Affiliation(s)
- YeQing Pi
- Department of Physiology, University of Wisconsin, Madison, WI 53706 USA
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Westfall MV, Borton AR. Role of troponin I phosphorylation in protein kinase C-mediated enhanced contractile performance of rat myocytes. J Biol Chem 2003; 278:33694-700. [PMID: 12815045 DOI: 10.1074/jbc.m305404200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Our goal was to define the role of phosphorylated cardiac troponin-I in the adult myocyte contractile performance response to activated protein kinase C. In agreement with earlier work, endothelin enhanced both adult rat myocyte contractile performance and cardiac troponin-I phosphorylation. Protein kinase C participated in both responses. The role of cardiac troponin-I phosphorylation in the contractile function response to protein kinase C was further investigated using gene transfer into myocytes of troponin-I isoforms/mutants lacking one or more phosphorylation sites previously identified in purified cardiac troponin-I. Sarcomeric replacement with slow skeletal troponin-I-abrogated protein kinase C-mediated troponin-I phosphorylation. In functional studies, endothelin slowed relaxation in myocytes expressing slow skeletal troponin-I, while the relaxation rate increased in myocytes expressing cardiac troponin-I. Based on these results, acceleration of myocyte relaxation during protein kinase C activation largely depended on cardiac troponin-I phosphorylation. Experiments with troponin-I isoform chimeras provided evidence that phosphorylation sites in the amino portion of cardiac troponin I-mediated the protein kinase C acceleration of relaxation. The cardiac troponin-I Thr-144 phosphorylation site identified in earlier biochemical studies was not significantly phosphorylated during the acute contractile response. Thus, amino-terminal protein kinase C-dependent phosphorylation sites in cardiac troponin-I are likely responsible for the accelerated relaxation observed in adult myocytes.
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Affiliation(s)
- Margaret V Westfall
- Department of Surgery, University of Michigan, Ann Arbor, Michigan 48109-0686, USA.
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Pyle WG, Chen Y, Hofmann PA. Cardioprotection through a PKC-dependent decrease in myofilament ATPase. Am J Physiol Heart Circ Physiol 2003; 285:H1220-8. [PMID: 12763745 DOI: 10.1152/ajpheart.00076.2003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Activation of myocardial kappa-opioid receptor-protein kinase C (PKC) pathways may improve postischemic contractile function through a myofilament reduction in ATP utilization. To test this, we first examined the effects of PKC inhibitors on kappa-opioid receptor-dependent cardioprotection. The kappa-opioid receptor agonist U50,488H (U50) increased postischemic left ventricular developed pressure and reduced postischemic end-diastolic pressure compared with controls. PKC inhibitors abolished the cardioprotective effects of U50. To determine whether kappa-opioid-PKC-dependent decreases in Ca2+-dependent actomyosin Mg2+-ATPase could account for cardioprotection, we subjected hearts to three separate actomyosin ATPase-lowering protocols. We observed that moderate decreases in myofibrillar ATPase were equally cardioprotective as kappa-opioid receptor stimulation. Immunoblot analysis and confocal microscopy revealed a kappa-opioid-induced increase in myofilament-associated PKC-epsilon, and myofibrillar Ca2+-independent PKC activity was increased after kappa-opioid stimulation. This PKC-myofilament association led to an increase in troponin I and C-protein phosphorylation. Thus we propose PKC-epsilon activation and translocation to the myofilaments causes a decrease in actomyosin ATPase, which contributes to the kappa-opioid receptor-dependent cardioprotective mechanism.
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Affiliation(s)
- W Glen Pyle
- Department of Physiology, University of Tennessee-Memphis, 894 Union Avenue, Memphis, TN 38163, USA
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48
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Abstract
Activation of protein kinase C (PKC) is thought to involve translocation to the particulate fraction. The present study demonstrates a membrane-associated, inactive pool of PKC in adult rat ventricular myocytes. Membranes were isolated from stimulated (phorbol 12-myristate 13-acetate (PMA), endothelin-1 (ET-1)) or control myocytes and PKC activity determined in the absence (active PKC) or presence (total PKC) of PMA. An inactive, PMA-responsive, pool of PKC was detected. In intact myocytes, PMA or ET-1 induced a translocation of PKC epsilon from the cytosol into the particulate fraction. In contrast, ET-1 decreased both total and active PKC in the membranes: this decrease was associated with a loss of PKC epsilon immunoreactivity. PMA increased the amount of membrane-associated, inactive PKC. Our results demonstrate the presence of a membrane-associated pool of PKC in cardiac myocytes that is differentially modulated by ET-1 or PMA.
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Affiliation(s)
- Benoit Boivin
- Institut de Cardiologie de Montréal, Centre de Recherche, 5000 rue Bélanger est, H1T 1C8, Montreal, Quebec, Canada
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Huang X, Li J, Foster D, Lemanski SL, Dube DK, Zhang C, Lemanski LF. Protein kinase C-mediated desmin phosphorylation is related to myofibril disarray in cardiomyopathic hamster heart. Exp Biol Med (Maywood) 2002; 227:1039-46. [PMID: 12486215 DOI: 10.1177/153537020222701113] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The cardiomyopathic (CM) Syrian golden hamster (strain UM-X7.1) exhibits a hereditary cardiomyopathy, which causes premature death resulting from congestive heart failure. The CM animals show extensive cardiac myofibril disarray and myocardial calcium overload. The present study has been undertaken to examine the role of desmin phosphorylation in myofibril disarray observed in CM hearts. The data from skinned myofibril protein phosphorylation assays have shown that desmin can be phosphorylated by protein kinase C (PKC). There is no significant difference in the content of desmin between CM and control hamster hearts. However, the desmin from CM hearts has a higher phosphorylation level than that of the normal hearts. Furthermore, we have examined the distribution of desmin and myofibril organization with immunofluorescent microscopy and immunogold electron microscopy in cultured cardiac myocytes after treatment with the PKC-activating phorbol ester, 12-O-tetradecanylphorbol-13-acetate (TPA). When the cultured normal hamster cardiac cells are treated with TPA, desmin filaments are disassembled and the myofibrils become disarrayed. The myofibril disarray closely mimics that observed in untreated CM cultures. These results suggest that disassembly of desmin filaments, which could be caused by PKC-mediated phosphorylation, may be a factor in myofibril disarray in cardiomyopathic cells and that the intermediate filament protein, desmin, plays an important role in maintaining myofibril alignment in cardiac cells.
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Affiliation(s)
- Xupei Huang
- Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL 33431, USA
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50
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VanWinkle WB, Snuggs MB, De Hostos EL, Buja LM, Woods A, Couchman JR. Localization of the transmembrane proteoglycan syndecan-4 and its regulatory kinases in costameres of rat cardiomyocytes: a deconvolution microscopic study. THE ANATOMICAL RECORD 2002; 268:38-46. [PMID: 12209563 DOI: 10.1002/ar.10130] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Syndecan-4 (syn-4), a transmembrane heparan sulfate-containing proteoglycan, is unique among the four members of the syndecan family in its specific cellular localization to complex cytoskeletal adhesion sites, i.e., focal adhesions. During early phenotypic redifferentiation of neonatal cardiomyocytes in culture, immunolocalization reveals syn-4 to be heavily concentrated in the perinuclear endoplasmic reticulum-Golgi region, with little found at the peripheral regions. Subsequently, syn-4 becomes localized to a cytoskeletal adhesion complex unique to striated muscle, the costamere. Soon after redifferentiation of myofibrils in cultured neonatal cardiomyocytes, syn-4 is present only in costameres, not in focal adhesions. In cultured adult cardiomyocytes, it is present in both costameres and focal adhesions-the latter in two distinct regions of the spread cardiomyocytes, reflecting localization with two types of actin-containing filaments. The fact that syn-4 is observed early in the costameric regions, as opposed to later in the focal adhesions, suggests that it may play an initial role in early adhesion/signal transduction mechanisms in close proximity to the contractile apparatus, as well as in transmission of contractile force to the collagenous extracellular matrix (ECM) which surrounds the cardiac myofibers in situ. With respect to possible regulatory mechanisms of syn-4, we localized syn-4 with both the epsilon isoform of protein kinase C and the tyrosine kinase pp60(csrc) in costameric regions. These findings suggest that syn-4 may not only play a role in cellular adhesion and contractile force transmission, it may also, through ser, thr, and tyr phosphorylation, be part of an interactive signal transduction mechanism in myocardial functioning via these adhesive cytoskeletal complexes.
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Affiliation(s)
- W Barry VanWinkle
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, Houston, Texas 77030, USA.
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