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Gergs U, Jahn T, Schulz N, Großmann C, Rueckschloss U, Demus U, Buchwalow IB, Neumann J. Protein Phosphatase 2A Improves Cardiac Functional Response to Ischemia and Sepsis. Int J Mol Sci 2022; 23:ijms23094688. [PMID: 35563079 PMCID: PMC9101092 DOI: 10.3390/ijms23094688] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 11/16/2022] Open
Abstract
Reversible protein phosphorylation is a posttranslational modification of regulatory proteins involved in cardiac signaling pathways. Here, we focus on the role of protein phosphatase 2A (PP2A) for cardiac gene expression and stress response using a transgenic mouse model with cardiac myocyte-specific overexpression of the catalytic subunit of PP2A (PP2A-TG). Gene and protein expression were assessed under basal conditions by gene chip analysis and Western blotting. Some cardiac genes related to the cell metabolism and to protein phosphorylation such as kinases and phosphatases were altered in PP2A-TG compared to wild type mice (WT). As cardiac stressors, a lipopolysaccharide (LPS)-induced sepsis in vivo and a global cardiac ischemia in vitro (stop-flow isolated perfused heart model) were examined. Whereas the basal cardiac function was reduced in PP2A-TG as studied by echocardiography or as studied in the isolated work-performing heart, the acute LPS- or ischemia-induced cardiac dysfunction deteriorated less in PP2A-TG compared to WT. From the data, we conclude that increased PP2A activity may influence the acute stress tolerance of cardiac myocytes.
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Affiliation(s)
- Ulrich Gergs
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, D-06097 Halle, Germany; (T.J.); (N.S.); (J.N.)
- Correspondence: ; Tel.: +49-345-557-4093
| | - Tina Jahn
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, D-06097 Halle, Germany; (T.J.); (N.S.); (J.N.)
| | - Nico Schulz
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, D-06097 Halle, Germany; (T.J.); (N.S.); (J.N.)
| | - Claudia Großmann
- Julius-Bernstein-Institut für Physiologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, D-06097 Halle, Germany;
| | - Uwe Rueckschloss
- Institut für Anatomie und Zellbiologie, Julius-Maximilians-Universität Würzburg, D-97070 Würzburg, Germany;
| | - Uta Demus
- Gesellschaft zur Förderung von Medizin-, Bio-und Umwelttechnologien e. V., D-06120 Halle, Germany;
| | - Igor B. Buchwalow
- Institut für Hämatopathologie, D-22547 Hamburg, Germany;
- Scientific and Educational Resource Center for Molecular Morphology, Peoples’ Friendship University of Russia, Moscow 117198, Russia
| | - Joachim Neumann
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, D-06097 Halle, Germany; (T.J.); (N.S.); (J.N.)
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Neumann J, Bödicker K, Buchwalow IB, Schmidbaur C, Ramos G, Frantz S, Hofmann U, Gergs U. Effects of acute ischemia and hypoxia in young and adult calsequestrin (CSQ2) knock-out and wild-type mice. Mol Cell Biochem 2022; 477:1789-1801. [PMID: 35312907 PMCID: PMC9068673 DOI: 10.1007/s11010-022-04407-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 03/03/2022] [Indexed: 11/26/2022]
Abstract
Calsequestrin (CSQ2) is the main Ca2+-binding protein in the sarcoplasmic reticulum of the mammalian heart. In order to understand the function of calsequestrin better, we compared two age groups (young: 4-5 months of age versus adult: 18 months of age) of CSQ2 knock-out mice (CSQ2(-/-)) and littermate wild-type mice (CSQ2(+/+)). Using echocardiography, in adult mice, the basal left ventricular ejection fraction and the spontaneous beating rate were lower in CSQ2(-/-) compared to CSQ2(+/+). The increase in ejection fraction by β-adrenergic stimulation (intraperitoneal injection of isoproterenol) was lower in adult CSQ2(-/-) versus adult CSQ2(+/+). After hypoxia in vitro (isolated atrial preparations) by gassing the organ bath buffer with 95% N2, force of contraction in electrically driven left atria increased to lower values in young CSQ2(-/-) than in young CSQ2(+/+). In addition, after global ischemia and reperfusion (buffer-perfused hearts according to Langendorff; 20-min ischemia and 15-min reperfusion), the rate of tension development was higher in young CSQ2(-/-) compared to young CSQ2(+/+). Finally, we evaluated signs of inflammation (immune cells, autoantibodies, and fibrosis). However, whereas no immunological alterations were found between all investigated groups, pronounced fibrosis was found in the ventricles of adult CSQ2(-/-) compared to all other groups. We suggest that in young mice, CSQ2 is important for cardiac performance especially in isolated cardiac preparations under conditions of impaired oxygen supply, but with differences between atrium and ventricle. Lack of CSQ2 leads age dependently to fibrosis and depressed cardiac performance in echocardiographic studies.
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Affiliation(s)
- Joachim Neumann
- Institute for Pharmacology and Toxicology, Medical Faculty, Martin Luther University Halle-Wittenberg, 06097 Halle, Germany
- Institut für Pharmakologie und Toxikologie, Martin-Luther-Universität Halle-Wittenberg, Medizinische Fakultät, Magdeburger Str. 4, 06112 Halle, Germany
| | - Konrad Bödicker
- Institute for Pharmacology and Toxicology, Medical Faculty, Martin Luther University Halle-Wittenberg, 06097 Halle, Germany
| | | | - Constanze Schmidbaur
- Institute for Pharmacology and Toxicology, Medical Faculty, Martin Luther University Halle-Wittenberg, 06097 Halle, Germany
| | - Gustavo Ramos
- Department of Internal Medicine and Comprehensive Heart Failure Center, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Stefan Frantz
- Department of Internal Medicine and Comprehensive Heart Failure Center, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Ulrich Hofmann
- Department of Internal Medicine and Comprehensive Heart Failure Center, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Ulrich Gergs
- Institute for Pharmacology and Toxicology, Medical Faculty, Martin Luther University Halle-Wittenberg, 06097 Halle, Germany
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Yoon S, Gergs U, McMullen JR, Eom GH. Overexpression of Heat Shock Protein 70 Improves Cardiac Remodeling and Survival in Protein Phosphatase 2A-Expressing Transgenic Mice with Chronic Heart Failure. Cells 2021; 10:cells10113180. [PMID: 34831402 PMCID: PMC8624068 DOI: 10.3390/cells10113180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 11/05/2021] [Accepted: 11/12/2021] [Indexed: 12/28/2022] Open
Abstract
Heat shock protein (HSP) 70 is a molecular chaperone that regulates protein structure in response to thermal stress. In addition, HSP70 is involved in post-translational modification and is related to the severity of some diseases. Here, we tested the functional relevance of long-lasting HSP70 expression in a model of nonischemic heart failure using protein phosphatase 2 catalytic subunit A (PP2CA)-expressing transgenic mice. These transgenic mice, with cardiac-specific overexpression of PP2CA, abruptly died after 12 weeks of postnatal life. Serial echocardiograms to assess cardiac function revealed that the ejection fraction (EF) was gradually decreased in transgenic PP2CA (TgPP2CA) mice. In addition, PP2CA expression exacerbated systolic dysfunction and LV dilatation, with free wall thinning, which are indicators of fatal dilated cardiomyopathy. Interestingly, simultaneous expression of HSP70 in double transgenic mice (dTg) significantly improved the dilated cardiomyopathy phenotype of TgPP2CA mice. We observed better survival, preserved EF, reduced chamber enlargement, and suppression of free wall thinning. In the proposed molecular mechanism, HSP70 preferentially regulates the phosphorylation of AKT. Phosphorylation of AKT was significantly reduced in TgPP2CA mice but was not significantly lower in dTg mice. Signal crosstalk between AKT and its substrates, in association with HSP70, might be a useful intervention for patients with nonischemic heart failure to suppress cardiac remodeling and improve survival.
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Affiliation(s)
- Somy Yoon
- Department of Pharmacology, Chonnam National University Medical School, Hwasun 58128, Korea
- Correspondence: (S.Y.); (G.H.E.); Tel.: +82-61-379-2843 (S.Y.); +82-61-379-2837 (G.H.E.)
| | - Ulrich Gergs
- Institute of Pharmacology and Toxicology, Faculty of Medicine, Martin Luther University Halle-Wittenberg, 06097 Halle, Germany;
| | | | - Gwang Hyeon Eom
- Department of Pharmacology, Chonnam National University Medical School, Hwasun 58128, Korea
- Correspondence: (S.Y.); (G.H.E.); Tel.: +82-61-379-2843 (S.Y.); +82-61-379-2837 (G.H.E.)
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Neumann J, Boknik P, Kirchhefer U, Gergs U. The role of PP5 and PP2C in cardiac health and disease. Cell Signal 2021; 85:110035. [PMID: 33964402 DOI: 10.1016/j.cellsig.2021.110035] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/16/2021] [Accepted: 05/03/2021] [Indexed: 02/08/2023]
Abstract
Protein phosphatases are important, for example, as functional antagonists of β-adrenergic stimulation of the mammalian heart. While β-adrenergic stimulations increase the phosphorylation state of regulatory proteins and therefore force of contraction in the heart, these phosphorylations are reversed and thus force is reduced by the activity of protein phosphatases. In this context the role of PP5 and PP2C is starting to unravel. They do not belong to the same family of phosphatases with regard to sequence homology, many similarities with regard to location, activation by lipids and putative substrates have been worked out over the years. We also suggest which pathways for regulation of PP5 and/or PP2C described in other tissues and not yet in the heart might be useful to look for in cardiac tissue. Both phosphatases might play a role in signal transduction of sarcolemmal receptors in the heart. Expression of PP5 and PP2C can be increased by extracellular stimuli in the heart. Because PP5 is overexpressed in failing animal and human hearts, and because overexpression of PP5 or PP2C leads to cardiac hypertrophy and KO of PP5 leads to cardiac hypotrophy, one might argue for a role of PP5 and PP2C in heart failure. Because PP5 and PP2C can reduce, at least in vitro, the phosphorylation state of proteins thought to be relevant for cardiac arrhythmias, a role of these phosphatases for cardiac arrhythmias is also probable. Thus, PP5 and PP2C might be druggable targets to treat important cardiac diseases like heart failure, cardiac hypertrophy and cardiac arrhythmias.
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Affiliation(s)
- Joachim Neumann
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Magdeburger Str. 4, D-06097 Halle, Germany.
| | - Peter Boknik
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Westfälische Wilhelms-Universität, Domagkstraße 12, D-48149 Münster, Germany.
| | - Uwe Kirchhefer
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Westfälische Wilhelms-Universität, Domagkstraße 12, D-48149 Münster, Germany.
| | - Ulrich Gergs
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Magdeburger Str. 4, D-06097 Halle, Germany.
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