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Kuprytė M, Lesauskaitė V, Siratavičiūtė V, Utkienė L, Jusienė L, Pangonytė D. Expression of Osteopontin and Gremlin 1 Proteins in Cardiomyocytes in Ischemic Heart Failure. Int J Mol Sci 2024; 25:8240. [PMID: 39125809 PMCID: PMC11311846 DOI: 10.3390/ijms25158240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Revised: 07/12/2024] [Accepted: 07/23/2024] [Indexed: 08/12/2024] Open
Abstract
A relevant role of osteopontin (OPN) and gremlin 1 (Grem1) in regulating cardiac tissue remodeling and formation of heart failure (HF) are documented, with the changes of OPN and Grem1 levels in blood plasma due to acute ischemia, ischemic heart disease-induced advanced HF or dilatative cardiomyopathy being the primary focus in most of these studies. However, knowledge on the early OPN and Grem1 proteins expression changes within cardiomyocytes during remodeling due to chronic ischemia remains insufficient. The aim of this study was to determine the OPN and Grem1 proteins expression changes in human cardiomyocytes at different stages of ischemic HF. A semi-quantitative immunohistochemical analysis was performed in 105 myocardial tissue samples obtained from the left cardiac ventricles. Increased OPN immunostaining intensity was already detected in the stage A HF group, compared to the control group (p < 0.001), and continued to increase in the stage B HF (p < 0.001), achieving the peak of immunostaining in the stages C/D HF group (p < 0.001). Similar data of Grem1 immunostaining intensity changes in cardiomyocytes were documented. Significantly positive correlations were detected between OPN, Grem1 expression in cardiomyocytes and their diameter as well as the length, in addition to positive correlation between OPN and Grem1 expression changes within cardiomyocytes. These novel findings suggest that OPN and Grem1 contribute significantly to reorganization of cellular geometry from the earliest stage of cardiomyocyte remodeling, providing new insights into the ischemic HF pathogenesis.
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Affiliation(s)
- Milda Kuprytė
- Laboratory of Cardiac Pathology, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50161 Kaunas, Lithuania; (M.K.); (V.S.); (L.U.); (L.J.)
| | - Vaiva Lesauskaitė
- Laboratory of Molecular Cardiology, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50161 Kaunas, Lithuania;
| | - Vitalija Siratavičiūtė
- Laboratory of Cardiac Pathology, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50161 Kaunas, Lithuania; (M.K.); (V.S.); (L.U.); (L.J.)
| | - Lina Utkienė
- Laboratory of Cardiac Pathology, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50161 Kaunas, Lithuania; (M.K.); (V.S.); (L.U.); (L.J.)
| | - Lina Jusienė
- Laboratory of Cardiac Pathology, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50161 Kaunas, Lithuania; (M.K.); (V.S.); (L.U.); (L.J.)
| | - Dalia Pangonytė
- Laboratory of Cardiac Pathology, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50161 Kaunas, Lithuania; (M.K.); (V.S.); (L.U.); (L.J.)
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2
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Fertala J, Wang ML, Rivlin M, Beredjiklian PK, Abboud J, Arnold WV, Fertala A. Extracellular Targets to Reduce Excessive Scarring in Response to Tissue Injury. Biomolecules 2023; 13:biom13050758. [PMID: 37238628 DOI: 10.3390/biom13050758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
Excessive scar formation is a hallmark of localized and systemic fibrotic disorders. Despite extensive studies to define valid anti-fibrotic targets and develop effective therapeutics, progressive fibrosis remains a significant medical problem. Regardless of the injury type or location of wounded tissue, excessive production and accumulation of collagen-rich extracellular matrix is the common denominator of all fibrotic disorders. A long-standing dogma was that anti-fibrotic approaches should focus on overall intracellular processes that drive fibrotic scarring. Because of the poor outcomes of these approaches, scientific efforts now focus on regulating the extracellular components of fibrotic tissues. Crucial extracellular players include cellular receptors of matrix components, macromolecules that form the matrix architecture, auxiliary proteins that facilitate the formation of stiff scar tissue, matricellular proteins, and extracellular vesicles that modulate matrix homeostasis. This review summarizes studies targeting the extracellular aspects of fibrotic tissue synthesis, presents the rationale for these studies, and discusses the progress and limitations of current extracellular approaches to limit fibrotic healing.
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Affiliation(s)
- Jolanta Fertala
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Mark L Wang
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA
| | - Michael Rivlin
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA
| | - Pedro K Beredjiklian
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA
| | - Joseph Abboud
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA
| | - William V Arnold
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA
| | - Andrzej Fertala
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Mamazhakypov A, Sartmyrzaeva M, Sarybaev AS, Schermuly R, Sydykov A. Clinical and Molecular Implications of Osteopontin in Heart Failure. Curr Issues Mol Biol 2022; 44:3573-3597. [PMID: 36005141 PMCID: PMC9406846 DOI: 10.3390/cimb44080245] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/04/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022] Open
Abstract
The matricellular protein osteopontin modulates cell-matrix interactions during tissue injury and healing. A complex multidomain structure of osteopontin enables it not only to bind diverse cell receptors but also to interact with various partners, including other extracellular matrix proteins, cytokines, and growth factors. Numerous studies have implicated osteopontin in the development and progression of myocardial remodeling in diverse cardiac diseases. Osteopontin influences myocardial remodeling by regulating extracellular matrix production, the activity of matrix metalloproteinases and various growth factors, inflammatory cell recruitment, myofibroblast differentiation, cardiomyocyte apoptosis, and myocardial vascularization. The exploitation of osteopontin loss- and gain-of-function approaches in rodent models provided an opportunity for assessment of the cell- and disease-specific contribution of osteopontin to myocardial remodeling. In this review, we summarize the recent knowledge on osteopontin regulation and its impact on various cardiac diseases, as well as delineate complex disease- and cell-specific roles of osteopontin in cardiac pathologies. We also discuss the current progress of therapeutics targeting osteopontin that may facilitate the development of a novel strategy for heart failure treatment.
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Affiliation(s)
- Argen Mamazhakypov
- Department of Internal Medicine, German Center for Lung Research (DZL), Justus Liebig University of Giessen, 35392 Giessen, Germany
| | - Meerim Sartmyrzaeva
- Department of Mountain and Sleep Medicine and Pulmonary Hypertension, National Center of Cardiology and Internal Medicine, Bishkek 720040, Kyrgyzstan
| | - Akpay Sh. Sarybaev
- Department of Mountain and Sleep Medicine and Pulmonary Hypertension, National Center of Cardiology and Internal Medicine, Bishkek 720040, Kyrgyzstan
| | - Ralph Schermuly
- Department of Internal Medicine, German Center for Lung Research (DZL), Justus Liebig University of Giessen, 35392 Giessen, Germany
| | - Akylbek Sydykov
- Department of Internal Medicine, German Center for Lung Research (DZL), Justus Liebig University of Giessen, 35392 Giessen, Germany
- Correspondence:
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Karmazyn M, Pierce GN, Fliegel L. The Remaining Conundrum of the Role of the Na +/H + Exchanger Isoform 1 (NHE1) in Cardiac Physiology and Pathology: Can It Be Rectified? Rev Cardiovasc Med 2022; 23:284. [PMID: 39076631 PMCID: PMC11266974 DOI: 10.31083/j.rcm2308284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 06/29/2022] [Accepted: 07/08/2022] [Indexed: 07/31/2024] Open
Abstract
The mammalian Na + /H + exchanger (NHE) is a family of ubiquitous membrane proteins present in humans. Isoform one (NHE1) is present on the plasma membrane and regulates intracellular pH by removal of one intracellular proton in exchange for one extracellular sodium thus functioning as an electroneutral process. Human NHE1 has a 500 amino acid membrane domain plus a C-terminal 315 amino acid, regulatory cytosolic tail. It is regulated through a cytosolic regulatory C-terminal tail which is subject to phosphorylation and is modulated by proteins and lipids. Substantial evidence has implicated NHE1 activity in both myocardial ischemia and reperfusion damage and myocardial remodeling resulting in heart failure. Experimental data show excellent cardioprotection with NHE1 inhibitors although results from clinical results have been mixed. In cardiac surgery patients receiving the NHE1 inhibitor cariporide, subgroups showed beneficial effects of treatment. However, in one trial this was associated with a significantly increased incidence of ischemic strokes. This likely reflected both inappropriate dosing regimens as well as overly high drug doses. We suggest that further progress towards NHE1 inhibition as a treatment for cardiovascular disease is warranted through the development of novel compounds to inhibit NHE1 that are structurally different than those previously used in compromised clinical trials. Some novel pyrazinoyl guanidine inhibitors of NHE1 are already in development and the recent elucidation of the three-dimensional structure of the NHE1 protein and identity of the inhibitor binding site may facilitate development. An alternative approach may also be to control the endogenous regulation of activity of NHE1, which is activated in disease.
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Affiliation(s)
- Morris Karmazyn
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Grant N. Pierce
- Institute of Cardiovascular Sciences, Albrechtsen Research Centre, St. Boniface Hospital, and Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R2H 2A6, Canada
| | - Larry Fliegel
- Department of Biochemistry, University Alberta, Edmonton, AB T6G 2H7, Canada
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Crosse EI, Gordon-Keylock S, Rybtsov S, Binagui-Casas A, Felchle H, Nnadi NC, Kirschner K, Chandra T, Tamagno S, Webb DJ, Rossi F, Anderson RA, Medvinsky A. Multi-layered Spatial Transcriptomics Identify Secretory Factors Promoting Human Hematopoietic Stem Cell Development. Cell Stem Cell 2020; 27:822-839.e8. [PMID: 32946788 PMCID: PMC7671940 DOI: 10.1016/j.stem.2020.08.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/25/2020] [Accepted: 08/07/2020] [Indexed: 01/30/2023]
Abstract
Hematopoietic stem cells (HSCs) first emerge in the embryonic aorta-gonad-mesonephros (AGM) region. Studies of model organisms defined intersecting signaling pathways that converge to promote HSC emergence predominantly in the ventral domain of the dorsal aorta. Much less is known about mechanisms driving HSC development in humans. Here, to identify secreted signals underlying human HSC development, we combined spatial transcriptomics analysis of dorsoventral polarized signaling in the aorta with gene expression profiling of sorted cell populations and single cells. Our analysis revealed a subset of aortic endothelial cells with a downregulated arterial signature and a predicted lineage relationship with the emerging HSC/progenitor population. Analysis of the ventrally polarized molecular landscape identified endothelin 1 as an important secreted regulator of human HSC development. The obtained gene expression datasets will inform future studies on mechanisms of HSC development in vivo and on generation of clinically relevant HSCs in vitro. Spatial transcriptome profiling of the human HSC developmental niche Characterization of an HSC precursor population at single-cell resolution Cardiac EGF pathway is ventrally enriched next to developing IAHCs/HSCs Ventrally secreted endothelin promotes development of HSCs
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Affiliation(s)
- Edie I Crosse
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK
| | | | - Stanislav Rybtsov
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Anahi Binagui-Casas
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Hannah Felchle
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Nneka C Nnadi
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Kristina Kirschner
- Institute of Cancer Sciences, University of Glasgow, Bearsden G61 1QH, UK
| | - Tamir Chandra
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Sara Tamagno
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK
| | - David J Webb
- BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - Fiona Rossi
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Richard A Anderson
- MRC Centre for Reproductive Health, University of Edinburgh, Edinburgh EH16 4TJ UK
| | - Alexander Medvinsky
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK.
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Abdelaziz Mohamed I, Gadeau AP, Hasan A, Abdulrahman N, Mraiche F. Osteopontin: A Promising Therapeutic Target in Cardiac Fibrosis. Cells 2019; 8:cells8121558. [PMID: 31816901 PMCID: PMC6952988 DOI: 10.3390/cells8121558] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/15/2019] [Accepted: 11/19/2019] [Indexed: 12/20/2022] Open
Abstract
Osteopontin (OPN) is recognized for its significant roles in both physiological and pathological processes. Initially, OPN was recognized as a cytokine with pro-inflammatory actions. More recently, OPN has emerged as a matricellular protein of the extracellular matrix (ECM). OPN is also known to be a substrate for proteolytic cleavage by several proteases that form an integral part of the ECM. In the adult heart under physiological conditions, basal levels of OPN are expressed. Increased expression of OPN has been correlated with the progression of cardiac remodeling and fibrosis to heart failure and the severity of the condition. The intricate process by which OPN mediates its effects include the coordination of intracellular signals necessary for the differentiation of fibroblasts into myofibroblasts, promoting angiogenesis, wound healing, and tissue regeneration. In this review, we discuss the role of OPN in contributing to the development of cardiac fibrosis and its suitability as a therapeutic target.
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Affiliation(s)
- Iman Abdelaziz Mohamed
- Visiting Scholar, Center of Excellence for Stem Cells and Regenerative Medicine (CESC), Zewail City of Science and Technology, 6th of October City, P.O. Box 12588 Giza Governorate, Egypt;
| | - Alain-Pierre Gadeau
- INSERM, Biology of Cardiovascular Disease, University of Bordeaux, U1034 Pessac, France;
| | - Anwarul Hasan
- Department of Mechanical and Industrial Engineering, College of Engineering, Qatar University, P.O. Box 2713 Doha, Qatar;
- Biomedical Research Center (BRC), Qatar University, P.O. Box 2713 Doha, Qatar
| | - Nabeel Abdulrahman
- Translational Research Institute, Academic Health System, Hamad Medical Corporation, P.O. Box 3050 Doha, Qatar;
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, P.O. Box 2713 Doha, Qatar
| | - Fatima Mraiche
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, P.O. Box 2713 Doha, Qatar
- Correspondence:
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7
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Structural and Functional Changes in the Na +/H + Exchanger Isoform 1, Induced by Erk1/2 Phosphorylation. Int J Mol Sci 2019; 20:ijms20102378. [PMID: 31091671 PMCID: PMC6566726 DOI: 10.3390/ijms20102378] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 12/15/2022] Open
Abstract
The human Na+/H+ exchanger isoform 1 (NHE1) is a plasma membrane transport protein that plays an important role in pH regulation in mammalian cells. Because of the generation of protons by intermediary metabolism as well as the negative membrane potential, protons accumulate within the cytosol. Extracellular signal-regulated kinase (ERK)-mediated regulation of NHE1 is important in several human pathologies including in the myocardium in heart disease, as well as in breast cancer as a trigger for growth and metastasis. NHE1 has a N-terminal, a 500 amino acid membrane domain, and a C-terminal 315 amino acid cytosolic domain. The C-terminal domain regulates the membrane domain and its effects on transport are modified by protein binding and phosphorylation. Here, we discuss the physiological regulation of NHE1 by ERK, with an emphasis on the critical effects on structure and function. ERK binds directly to the cytosolic domain at specific binding domains. ERK also phosphorylates NHE1 directly at multiple sites, which enhance NHE1 activity with subsequent downstream physiological effects. The NHE1 cytosolic regulatory tail possesses both ordered and disordered regions, and the disordered regions are stabilized by ERK-mediated phosphorylation at a phosphorylation motif. Overall, ERK pathway mediated phosphorylation modulates the NHE1 tail, and affects the activity, structure, and function of this membrane protein.
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Abdulrahman N, Jaspard-Vinassa B, Fliegel L, Jabeen A, Riaz S, Gadeau AP, Mraiche F. Na +/H + exchanger isoform 1-induced osteopontin expression facilitates cardiac hypertrophy through p90 ribosomal S6 kinase. Physiol Genomics 2018; 50:332-342. [PMID: 29473817 DOI: 10.1152/physiolgenomics.00133.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cardiovascular diseases are the leading cause of death worldwide. One in three cases of heart failure is due to dilated cardiomyopathy. The Na+/H+ exchanger isoform 1 (NHE1), a multifunctional protein and the key pH regulator in the heart, has been demonstrated to be increased in this condition. We have previously demonstrated that elevated NHE1 activity induced cardiac hypertrophy in vivo. Furthermore, the overexpression of active NHE1 elicited modulation of gene expression in cardiomyocytes including an upregulation of myocardial osteopontin (OPN) expression. To determine the role of OPN in inducing NHE1-mediated cardiomyocyte hypertrophy, double transgenic mice expressing active NHE1 and OPN knockout were generated and assessed by echocardiography and the cardiac phenotype. Our studies showed that hearts expressing active NHE1 exhibited cardiac remodeling indicated by increased systolic and diastolic left ventricular internal diameter and increased ventricular volume. Moreover, these hearts demonstrated impaired function with decreased fractional shortening and ejection fraction. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) mRNA was upregulated, and there was an increase in heart cell cross-sectional area confirming the cardiac hypertrophic effect. Moreover, NHE1 transgenic mice also showed increased collagen deposition, upregulation of CD44 and phosphorylation of p90 ribosomal s6 kinase (RSK), effects that were regressed in OPN knockout mice. In conclusion, we developed an interesting comparative model of active NHE1 transgenic mouse lines which express a dilated hypertrophic phenotype expressing CD44 and phosphorylated RSK, effects which were regressed in absence of OPN.
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Affiliation(s)
| | | | - Larry Fliegel
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta , Edmonton, Alberta , Canada
| | | | - Sadaf Riaz
- College of Pharmacy, Qatar University , Doha , Qatar
| | - Alain-Pierre Gadeau
- University of Bordeaux, INSERM, Biology of Cardiovascular Disease, U1034, Pessac , France
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Holmgren G, Sartipy P, Andersson CX, Lindahl A, Synnergren J. Expression Profiling of Human Pluripotent Stem Cell-Derived Cardiomyocytes Exposed to Doxorubicin—Integration and Visualization of Multi-Omics Data. Toxicol Sci 2018; 163:182-195. [DOI: 10.1093/toxsci/kfy012] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Gustav Holmgren
- Systems Biology Research Center, School of Bioscience, University of Skövde, Skövde SE-541 28, Sweden
- Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg SE-413 45, Sweden
- Takara Bio Europe AB, Gothenburg SE-413 46, Sweden
| | - Peter Sartipy
- Systems Biology Research Center, School of Bioscience, University of Skövde, Skövde SE-541 28, Sweden
- AstraZeneca Gothenburg, CVMD GMed, GMD, Mölndal SE-430 51, Sweden
| | | | - Anders Lindahl
- Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg SE-413 45, Sweden
| | - Jane Synnergren
- Systems Biology Research Center, School of Bioscience, University of Skövde, Skövde SE-541 28, Sweden
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10
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Li X, Augustine A, Sun D, Li L, Fliegel L. Activation of the Na +/H + exchanger in isolated cardiomyocytes through β-Raf dependent pathways. Role of Thr 653 of the cytosolic tail. J Mol Cell Cardiol 2016; 99:65-75. [PMID: 27555478 DOI: 10.1016/j.yjmcc.2016.08.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 08/04/2016] [Accepted: 08/19/2016] [Indexed: 10/21/2022]
Abstract
The mammalian Na+/H+ exchanger isoform 1 (NHE1) is a ubiquitous plasma membrane protein that is a key regulator of intracellular pH in isolated cardiomyocytes. A 500 amino acid membrane domain removes protons and is regulated by a 315 amino acid cytosolic domain. In the myocardium, aberrant regulation of NHE1 contributes to ischemia reperfusion damage and to heart hypertrophy. We examined mechanisms of regulation of NHE1 in the myocardium by endothelin and β-Raf. Endothelin stimulated NHE1 activity and activated Erk-dependent pathways. Inhibition of β-Raf reduced NHE1 activity and Erk-pathway activation. We demonstrated that myocardial β-Raf binds to the C-terminal 182 amino acids of the NHE1 protein and that β-Raf is associated with NHE1 in intact cardiomyocytes. NHE1 was phosphorylated in vivo and the protein kinase inhibitor sorafenib reduced NHE1 phosphorylation levels. Immunoprecipitates of β-Raf from cardiomyocytes phosphorylated the C-terminal 182 amino acids of NHE1 and mass spectrometry analysis showed that amino acid Thr653 was phosphorylated. Mutation of this amino acid to Ala resulted in defective activity while mutation to Asp restored the activity. The results demonstrate that Thr653 is an important regulatory amino acid of NHE1 that is activated through β-Raf dependent pathways by phosphorylation either directly or indirectly by β-Raf, and this affects NHE1 activity.
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Affiliation(s)
- Xiuju Li
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
| | - Aruna Augustine
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
| | - Difei Sun
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada.
| | - Liang Li
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada.
| | - Larry Fliegel
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
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11
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Lou Y, Zhang F, Luo Y, Wang L, Huang S, Jin F. Serum and Glucocorticoid Regulated Kinase 1 in Sodium Homeostasis. Int J Mol Sci 2016; 17:ijms17081307. [PMID: 27517916 PMCID: PMC5000704 DOI: 10.3390/ijms17081307] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/02/2016] [Accepted: 08/03/2016] [Indexed: 12/13/2022] Open
Abstract
The ubiquitously expressed serum and glucocorticoid regulated kinase 1 (SGK1) is tightly regulated by osmotic and hormonal signals, including glucocorticoids and mineralocorticoids. Recently, SGK1 has been implicated as a signal hub for the regulation of sodium transport. SGK1 modulates the activities of multiple ion channels and carriers, such as epithelial sodium channel (ENaC), voltage-gated sodium channel (Nav1.5), sodium hydrogen exchangers 1 and 3 (NHE1 and NHE3), sodium-chloride symporter (NCC), and sodium-potassium-chloride cotransporter 2 (NKCC2); as well as the sodium-potassium adenosine triphosphatase (Na+/K+-ATPase) and type A natriuretic peptide receptor (NPR-A). Accordingly, SGK1 is implicated in the physiology and pathophysiology of Na+ homeostasis. Here, we focus particularly on recent findings of SGK1’s involvement in Na+ transport in renal sodium reabsorption, hormone-stimulated salt appetite and fluid balance and discuss the abnormal SGK1-mediated Na+ reabsorption in hypertension, heart disease, edema with diabetes, and embryo implantation failure.
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Affiliation(s)
- Yiyun Lou
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
- Department of Gynaecology, Hangzhou Hospital of Traditional Chinese Medicine, Hangzhou 310007, Zhejiang, China.
| | - Fan Zhang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Yuqin Luo
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Liya Wang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Shisi Huang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Fan Jin
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
- Key Laboratory of Reproductive Genetics, National Ministry of Education (Zhejiang University), Women's Reproductive Healthy Laboratory of Zhejiang Province, Hangzhou 310058, Zhejiang, China.
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