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Trębińska-Stryjewska A, Wakula M, Chmielarczyk M, Grzybowska EA. HAX1: A versatile, intrinsically disordered regulatory protein. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119538. [PMID: 37454914 DOI: 10.1016/j.bbamcr.2023.119538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/20/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
HAX1 is a relatively small, ubiquitously expressed, predominantly mitochondrial, intrinsically disordered protein. It has been implicated in the regulation of apoptosis, cell migration, calcium cycling, proteostasis, angiogenesis, autophagy and translation. A wide spectrum of functions, numerous interactions and still elusive molecular mechanisms of action make HAX1 an intriguing subject of research. Moreover, HAX1 is involved in the pathogenesis of diseases; its deficiency leads to neutropenia and its overexpression is associated with cancer. In this review we aim to describe the characteristics of HAX1 gene and protein, and comprehensively discuss its multiple functions, highlighting the emerging role of HAX1 in protection from stress and apoptosis through maintaining cellular proteostasis and homeostasis.
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Affiliation(s)
| | - Maciej Wakula
- Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland
| | | | - Ewa A Grzybowska
- Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland.
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2
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Vafiadaki E, Glijnis PC, Doevendans PA, Kranias EG, Sanoudou D. Phospholamban R14del disease: The past, the present and the future. Front Cardiovasc Med 2023; 10:1162205. [PMID: 37144056 PMCID: PMC10151546 DOI: 10.3389/fcvm.2023.1162205] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 04/03/2023] [Indexed: 05/06/2023] Open
Abstract
Arrhythmogenic cardiomyopathy affects significant number of patients worldwide and is characterized by life-threatening ventricular arrhythmias and sudden cardiac death. Mutations in multiple genes with diverse functions have been reported to date including phospholamban (PLN), a key regulator of sarcoplasmic reticulum (SR) Ca2+ homeostasis and cardiac contractility. The PLN-R14del variant in specific is recognized as the cause in an increasing number of patients worldwide, and extensive investigations have enabled rapid advances towards the delineation of PLN-R14del disease pathogenesis and discovery of an effective treatment. We provide a critical overview of current knowledge on PLN-R14del disease pathophysiology, including clinical, animal model, cellular and biochemical studies, as well as diverse therapeutic approaches that are being pursued. The milestones achieved in <20 years, since the discovery of the PLN R14del mutation (2006), serve as a paradigm of international scientific collaboration and patient involvement towards finding a cure.
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Affiliation(s)
- Elizabeth Vafiadaki
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Correspondence: Elizabeth Vafiadaki Despina Sanoudou
| | - Pieter C. Glijnis
- Stichting Genetische Hartspierziekte PLN, Phospholamban Foundation, Wieringerwerf, Netherlands
| | - Pieter A. Doevendans
- Netherlands Heart Institute, Utrecht, Netherlands
- Department of Cardiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Evangelia G. Kranias
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Despina Sanoudou
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Clinical Genomics and Pharmacogenomics Unit, 4th Department of Internal Medicine, Attikon Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Center for New Biotechnologies and Precision Medicine, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Correspondence: Elizabeth Vafiadaki Despina Sanoudou
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3
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Fischer M, Jakab M, Hirt MN, Werner TR, Engelhardt S, Sarikas A. Identification of hypertrophy-modulating Cullin-RING ubiquitin ligases in primary cardiomyocytes. Front Physiol 2023; 14:1134339. [PMID: 36969608 PMCID: PMC10030680 DOI: 10.3389/fphys.2023.1134339] [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: 12/30/2022] [Accepted: 02/27/2023] [Indexed: 03/29/2023] Open
Abstract
Cullin-RING ubiquitin ligases (CRL) regulate numerous biological processes in the heart and have been implicated in regulating cardiac hypertrophy. This study aimed to identify novel hypertrophy-modulating CRLs in cardiomyocytes (CM). A functional genomic approach using siRNA-mediated depletion and automated microscopy was employed to screen for cell size-modulating CRLs in neonatal rat CM. Screening hits were confirmed by 3H-isoleucine incorporation. Of 43 targets screened, siRNA-mediated depletion of Fbxo6, Fbxo45, and Fbxl14 resulted in decreased cell size, whereas depletion of Fbxo9, Fbxo25, Fbxo30, Fbxo32, Fbxo33, Cullin1, Roc1, Ddb1, Fbxw4, and Fbxw5 led to a markedly increased cell size under basal conditions. In CM stimulated with phenylephrine (PE), depletion of Fbxo6, Fbxo25, Fbxo33, Fbxo45, and Fbxw4 further augmented PE-induced hypertrophy. As a proof-of-concept, the CRLFbox25 was analysed by transverse aortic constriction (TAC) resulting in a 4.5-fold increase in Fbxo25 protein concentrations compared to control animals. In cell culture, siRNA-mediated depletion of Fbxo25 resulted in a ∼ 37% increase in CM cell size and ∼41% increase in 3H-isoleucine incorporation. Depleting Fbxo25 resulted in upregulation of Anp and Bnp. In summary, we identified 13 novel CRLs as positive or negative regulators of CM hypertrophy. Of these, CRLFbox25 was further characterized, as a potential modulator of cardiac hypertrophy.
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Affiliation(s)
- Maximillian Fischer
- Institute of Pharmacology and Toxicology, Technische Universität München, Munich, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich, Germany
- Correspondence: Maximillian Fischer, ; Antonio Sarikas,
| | - Moritz Jakab
- Institute of Pharmacology and Toxicology, Technische Universität München, Munich, Germany
| | - Marc N. Hirt
- Institute of Pharmacology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Tessa R. Werner
- Institute of Pharmacology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Stefan Engelhardt
- Institute of Pharmacology and Toxicology, Technische Universität München, Munich, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich, Germany
| | - Antonio Sarikas
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
- Correspondence: Maximillian Fischer, ; Antonio Sarikas,
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4
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Rogalska ME, Vafiadaki E, Erpapazoglou Z, Haghighi K, Green L, Mantzoros CS, Hajjar RJ, Tranter M, Karakikes I, Kranias EG, Stillitano F, Kafasla P, Sanoudou D. Isoform changes of action potential regulators in the ventricles of arrhythmogenic phospholamban-R14del humanized mouse hearts. Metabolism 2023; 138:155344. [PMID: 36375644 DOI: 10.1016/j.metabol.2022.155344] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 10/30/2022] [Accepted: 11/01/2022] [Indexed: 11/13/2022]
Abstract
Arrhythmogenic cardiomyopathy (ACM) is characterized by life-threatening ventricular arrhythmias and sudden cardiac death and affects hundreds of thousands of patients worldwide. The deletion of Arginine 14 (p.R14del) in the phospholamban (PLN) gene has been implicated in the pathogenesis of ACM. PLN is a key regulator of sarcoplasmic reticulum (SR) Ca2+ cycling and cardiac contractility. Despite global gene and protein expression studies, the molecular mechanisms of PLN-R14del ACM pathogenesis remain unclear. Using a humanized PLN-R14del mouse model and human induced pluripotent stem cell derived cardiomyocytes (iPSC-CMs), we investigated the transcriptome-wide mRNA splicing changes associated with the R14del mutation. We identified >200 significant alternative splicing (AS) events and distinct AS profiles were observed in the right (RV) and left (LV) ventricles in PLN-R14del compared to WT mouse hearts. Enrichment analysis of the AS events showed that the most affected biological process was associated with "cardiac cell action potential", specifically in the RV. We found that splicing of 2 key genes, Trpm4 and Camk2d, which encode proteins regulating calcium homeostasis in the heart, were altered in PLN-R14del mouse hearts and human iPSC-CMs. Bioinformatical analysis pointed to the tissue-specific splicing factors Srrm4 and Nova1 as likely upstream regulators of the observed splicing changes in the PLN-R14del cardiomyocytes. Our findings suggest that aberrant splicing may affect Ca2+-homeostasis in the heart, contributing to the increased risk of arrythmogenesis in PLN-R14del ACM.
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Affiliation(s)
- Malgorzata E Rogalska
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain
| | - Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
| | - Zoi Erpapazoglou
- Institute for Fundamental Biomedical Research, B.S.R.C. "Alexander Fleming", 16672 Athens, Greece
| | - Kobra Haghighi
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Lisa Green
- Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Christos S Mantzoros
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA; Section of Endocrinology, Boston VA Healthcare System, Harvard Medical School, Boston, MA 02215, USA
| | | | - Michael Tranter
- Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Ioannis Karakikes
- Department of Cardiothoracic Surgery and Cardiovascular Institute, Stanford University School of Medicine, 240 Pasteur Dr, Stanford, CA 94304, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Francesca Stillitano
- Division Heart and Lung, Department of Cardiology, University Medical Center Utrecht, 3584, CX, Utrecht, the Netherlands
| | - Panagiota Kafasla
- Institute for Fundamental Biomedical Research, B.S.R.C. "Alexander Fleming", 16672 Athens, Greece
| | - Despina Sanoudou
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece; Clinical Genomics and Pharmacogenomics Unit, 4(th) Department of Internal Medicine, Attikon Hospital, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; Center for New Biotechnologies and Precision Medicine, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece.
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5
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Neuroprotective roles of HAX-1 in ischemic neuronal injury. Exp Neurol 2021; 339:113642. [PMID: 33600816 DOI: 10.1016/j.expneurol.2021.113642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 01/31/2021] [Accepted: 02/12/2021] [Indexed: 11/22/2022]
Abstract
Hematopoietic cell-specific protein 1 associated protein X-1 (HAX-1) is a novel mitochondrial protein that regulates oxidative stress-induced apoptosis. However, the roles of HAX-1 in ischemic neuronal injury have not been thoroughly elucidated. In this study, the expression and roles of HAX-1 after ischemic stress were investigated using in vivo and in vitro models. The effect of oxidative stress on the regulation of HAX-1 was examined using knockout mice lacking nicotinamide-adenine dinucleotide phosphate oxidase 2 (NOX2), which is a major source of reactive oxygen species (ROS) after cerebral ischemia. Male C57BL/6 J mice were subjected to transient forebrain ischemia induced by 22-min occlusion of the bilateral common carotid arteries, and striatum samples were analyzed. For in vitro ischemic experiments, oxygen and glucose deprivation (OGD) in a rat pheochromocytoma cell line was utilized. Western blotting and immunofluorescence analysis revealed HAX-1 expression in neuronal mitochondria, which was significantly decreased after ischemia in vivo and in vitro. In NOX2 knockout mice, ischemia-induced decrease in HAX-1 expression and ischemic neuronal injury was significantly alleviated compared to those in wild-type mice. Inhibition of HAX-1 using small interfering RNA significantly increased injury in cultured cells after OGD. These findings suggest that HAX-1 has a neuroprotective effect against ischemic neuronal injury, and downregulation of HAX-1 by NOX2-produced ROS induces apoptosis after cerebral ischemia.
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Hummitzsch K, Hatzirodos N, Macpherson AM, Schwartz J, Rodgers RJ, Irving-Rodgers HF. Transcriptome analyses of ovarian stroma: tunica albuginea, interstitium and theca interna. Reproduction 2020; 157:545-565. [PMID: 30925461 DOI: 10.1530/rep-18-0323] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 03/29/2019] [Indexed: 01/15/2023]
Abstract
The ovary has specialised stromal compartments, including the tunica albuginea, interstitial stroma and theca interna, which develops concurrently with the follicular antrum. To characterise the molecular determinants of these compartments, stroma adjacent to preantral follicles (pre-theca), interstitium and tunica albuginea were laser microdissected (n = 4 per group) and theca interna was dissected from bovine antral follicles (n = 6). RNA microarray analysis showed minimal differences between interstitial stroma and pre-theca, and these were combined for some analyses and referred to as stroma. Genes significantly upregulated in theca interna compared to stroma included INSL3, LHCGR, HSD3B1, CYP17A1, ALDH1A1, OGN, POSTN and ASPN. Quantitative RT-PCR showed significantly greater expression of OGN and LGALS1 in interstitial stroma and theca interna versus tunica and greater expression of ACD in tunica compared to theca interna. PLN was significantly higher in interstitial stroma compared to tunica and theca. Ingenuity pathway, network and upstream regulator analyses were undertaken. Cell survival was also upregulated in theca interna. The tunica albuginea was associated with GPCR and cAMP signalling, suggesting tunica contractility. It was also associated with TGF-β signalling and increased fibrous matrix. Western immunoblotting was positive for OGN, LGALS1, ALDH1A1, ACD and PLN with PLN and OGN highly expressed in tunica and interstitial stroma (each n = 6), but not in theca interna from antral follicles (n = 24). Immunohistochemistry localised LGALS1 and POSTN to extracellular matrix and PLN to smooth muscle cells. These results have identified novel differences between the ovarian stromal compartments.
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Affiliation(s)
- Katja Hummitzsch
- Discipline of Obstetrics and Gynaecology, School of Medicine, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
| | - Nicholas Hatzirodos
- Discipline of Obstetrics and Gynaecology, School of Medicine, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
| | - Anne M Macpherson
- Discipline of Obstetrics and Gynaecology, School of Medicine, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
| | - Jeff Schwartz
- School of Medicine, Griffith University, Gold Coast, Queensland, Australia
| | - Raymond J Rodgers
- Discipline of Obstetrics and Gynaecology, School of Medicine, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
| | - Helen F Irving-Rodgers
- Discipline of Obstetrics and Gynaecology, School of Medicine, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia.,School of Medical Science, Griffith University, Gold Coast, Queensland, Australia
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7
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Tiano F, Amati F, Cherubini F, Morini E, Vancheri C, Maletta S, Fortuni S, Serio D, Quatrana A, Luffarelli R, Benini M, Alfedi G, Panarello L, Rufini A, Toschi N, Frontali M, Romano S, Marcotulli C, Casali C, Gioiosa S, Mariotti C, Mongelli A, Fichera M, Condò I, Novelli G, Testi R, Malisan F. Frataxin deficiency in Friedreich's ataxia is associated with reduced levels of HAX-1, a regulator of cardiomyocyte death and survival. Hum Mol Genet 2020; 29:471-482. [PMID: 31943004 DOI: 10.1093/hmg/ddz306] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 11/29/2019] [Accepted: 12/10/2019] [Indexed: 12/31/2022] Open
Abstract
Frataxin deficiency, responsible for Friedreich's ataxia (FRDA), is crucial for cell survival since it critically affects viability of neurons, pancreatic beta cells and cardiomyocytes. In FRDA, the heart is frequently affected with typical manifestation of hypertrophic cardiomyopathy, which can progress to heart failure and cause premature death. A microarray analysis performed on FRDA patient's lymphoblastoid cells stably reconstituted with frataxin, indicated HS-1-associated protein X-1 (HAX-1) as the most significantly upregulated transcript (FC = +2, P < 0.0006). quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) and western blot analysis performed on (I) HEK293 stably transfected with empty vector compared to wild-type frataxin and (II) lymphoblasts from FRDA patients show that low frataxin mRNA and protein expression correspond to reduced levels of HAX-1. Frataxin overexpression and silencing were also performed in the AC16 human cardiomyocyte cell line. HAX-1 protein levels are indeed regulated through frataxin modulation. Moreover, correlation between frataxin and HAX-1 was further evaluated in peripheral blood mononuclear cells (PBMCs) from FRDA patients and from non-related healthy controls. A regression model for frataxin which included HAX-1, group membership and group* HAX-1 interaction revealed that frataxin and HAX-1 are associated both at mRNA and protein levels. Additionally, a linked expression of FXN, HAX-1 and antioxidant defence proteins MnSOD and Nrf2 was observed both in PBMCs and AC16 cardiomyocytes. Our results suggest that HAX-1 could be considered as a potential biomarker of cardiac disease in FRDA and the evaluation of its expression might provide insights into its pathogenesis as well as improving risk stratification strategies.
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Affiliation(s)
- Francesca Tiano
- Laboratory of Signal Transduction, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Francesca Amati
- Section of Medical Genetics, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
- Department of Human Sciences and Quality of Life Promotion, University San Raffaele, 00166 Rome, Italy
| | - Fabio Cherubini
- Laboratory of Signal Transduction, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Elena Morini
- Section of Medical Genetics, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Chiara Vancheri
- Section of Medical Genetics, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Sara Maletta
- Section of Medical Genetics, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Silvia Fortuni
- Laboratory of Signal Transduction, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Dario Serio
- Laboratory of Signal Transduction, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Andrea Quatrana
- Laboratory of Signal Transduction, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Riccardo Luffarelli
- Laboratory of Signal Transduction, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
- Fratagene Therapeutics Srl, 00133 Rome, Italy
| | - Monica Benini
- Laboratory of Signal Transduction, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
- Fratagene Therapeutics Srl, 00133 Rome, Italy
| | - Giulia Alfedi
- Laboratory of Signal Transduction, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
- Fratagene Therapeutics Srl, 00133 Rome, Italy
| | - Luca Panarello
- Laboratory of Signal Transduction, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Alessandra Rufini
- Laboratory of Signal Transduction, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
- Fratagene Therapeutics Srl, 00133 Rome, Italy
| | - Nicola Toschi
- Medical Physics Section, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
- A.A. Martinos Center for Biomedical Imaging, Harvard Medical School, Charlestown, MA 02129, USA
| | - Marina Frontali
- CNR Institute of Translational Pharmacology, 00133 Rome, Italy
| | - Silvia Romano
- Neurosciences, Mental Health and Sensory Organs (NESMOS) Department, Faculty of Medicine and Psychology, Sapienza University, 00189 Rome, Italy
| | - Christian Marcotulli
- Department of Medical Surgical Sciences and Biotechnologies, Polo Pontino-Sapienza University of Rome, 04100 Latina, Italy
| | - Carlo Casali
- Department of Medical Surgical Sciences and Biotechnologies, Polo Pontino-Sapienza University of Rome, 04100 Latina, Italy
| | - Silvia Gioiosa
- SCAI (Super Computing Applications and Innovations) CINECA, 00185 Rome, Italy
| | - Caterina Mariotti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy
| | - Alessia Mongelli
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy
| | - Mario Fichera
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy
| | - Ivano Condò
- Laboratory of Signal Transduction, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Giuseppe Novelli
- Section of Medical Genetics, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
- Neuromed Institute, IRCCS, 86077 Pozzilli, Italy
| | - Roberto Testi
- Laboratory of Signal Transduction, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
- Fratagene Therapeutics Srl, 00133 Rome, Italy
| | - Florence Malisan
- Laboratory of Signal Transduction, Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 00133 Rome, Italy
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8
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Larsen EK, Weber DK, Wang S, Gopinath T, Blackwell DJ, Dalton MP, Robia SL, Gao J, Veglia G. Intrinsically disordered HAX-1 regulates Ca 2+ cycling by interacting with lipid membranes and the phospholamban cytoplasmic region. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2020; 1862:183034. [PMID: 31400305 PMCID: PMC6899184 DOI: 10.1016/j.bbamem.2019.183034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 07/09/2019] [Accepted: 07/30/2019] [Indexed: 01/14/2023]
Abstract
Hematopoietic-substrate-1 associated protein X-1 (HAX-1) is a 279 amino acid protein expressed ubiquitously. In cardiac muscle, HAX-1 was found to modulate the sarcoendoplasmic reticulum calcium ATPase (SERCA) by shifting its apparent Ca2+ affinity (pCa). It has been hypothesized that HAX-1 binds phospholamban (PLN), enhancing its inhibitory function on SERCA. HAX-1 effects are reversed by cAMP-dependent protein kinase A that phosphorylates PLN at Ser16. To date, the molecular mechanisms for HAX-1 regulation of the SERCA/PLN complex are still unknown. Using enzymatic, in cell assays, circular dichroism, and NMR spectroscopy, we found that in the absence of a binding partner HAX-1 is essentially disordered and adopts a partial secondary structure upon interaction with lipid membranes. Also, HAX-1 interacts with the cytoplasmic region of monomeric and pentameric PLN as detected by NMR and in cell FRET assays, respectively. We propose that the regulation of the SERCA/PLN complex by HAX-1 is mediated by its interactions with lipid membranes, adding another layer of control in Ca2+ homeostatic balance in the heart muscle.
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Affiliation(s)
- Erik K Larsen
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Daniel K Weber
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Songlin Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Tata Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | | | - Michael P Dalton
- Department of Physiology, Loyola University, Maywood, IL 60153, USA
| | - Seth L Robia
- Department of Physiology, Loyola University, Maywood, IL 60153, USA
| | - Jiali Gao
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA; School of Chemical Biology and Technology, Beijing University Graduate School, Shenzhen 518055, China
| | - Gianluigi Veglia
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA; Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
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9
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10
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Arvanitis DA, Vafiadaki E, Johnson DM, Kranias EG, Sanoudou D. The Histidine-Rich Calcium Binding Protein in Regulation of Cardiac Rhythmicity. Front Physiol 2018; 9:1379. [PMID: 30319456 PMCID: PMC6171002 DOI: 10.3389/fphys.2018.01379] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 09/11/2018] [Indexed: 12/16/2022] Open
Abstract
Sudden unexpected cardiac death (SCD) accounts for up to half of all-cause mortality of heart failure patients. Standardized cardiology tools such as electrocardiography, cardiac imaging, electrophysiological and serum biomarkers cannot accurately predict which patients are at risk of life-threatening arrhythmic episodes. Recently, a common variant of the histidine-rich calcium binding protein (HRC), the Ser96Ala, was identified as a potent biomarker of malignant arrhythmia triggering in these patients. HRC has been shown to be involved in the regulation of cardiac sarcoplasmic reticulum (SR) Ca2+ cycling, by binding and storing Ca2+ in the SR, as well as interacting with the SR Ca2+ uptake and release complexes. The underlying mechanisms, elucidated by studies at the molecular, biochemical, cellular and intact animal levels, indicate that transversion of Ser96 to Ala results in abolishment of an HRC phosphorylation site by Fam20C kinase and dysregulation of SR Ca2+ cycling. This is mediated through aberrant SR Ca2+ release by the ryanodine receptor (RyR2) quaternary complex, due to the impaired HRC/triadin interaction, and depressed SR Ca2+ uptake by the sarco/endoplasmic reticulum Ca2+ ATPase (SERCA2) pump, due to the impaired HRC/SERCA2 interaction. Pharmacological intervention with KN-93, an inhibitor of Ca2+/calmodulin-dependent protein kinase II (CaMKII), in the HRC Ser96Ala mouse model, reduced the occurrence of malignant cardiac arrhythmias. Herein, we summarize the current evidence on the pivotal role of HRC in the regulation of cardiac rhythmicity and the importance of HRC Ser96Ala as a genetic modifier for arrhythmias in the setting of heart failure.
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Affiliation(s)
- Demetrios A Arvanitis
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Daniel M Johnson
- Department of Cardiothoracic Surgery, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Evangelia G Kranias
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Athens, Greece.,Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Despina Sanoudou
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Athens, Greece.,Clinical Genomics and Pharmacogenomics Unit, 4th Department of Internal Medicine, Attikon Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
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11
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Lu X, Xue P, Fu L, Zhang J, Jiang J, Guo X, Bao G, Xu G, Sun Y, Chen J, Cui Z. HAX1 is associated with neuronal apoptosis and astrocyte proliferation after spinal cord injury. Tissue Cell 2018; 54:1-9. [PMID: 30309497 DOI: 10.1016/j.tice.2018.07.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 07/05/2018] [Accepted: 07/05/2018] [Indexed: 12/13/2022]
Abstract
HS1-associated protein X-1 (HAX1) is a class of multifunctional protein, participated in various physiological processes such as cell apoptosis, proliferation and motility. However, the HAX1 expression and function in the spinal cord injury (SCI) pathological process have not been investigated. In our current research, the rat model of SCI was established, and then we explored the possible role of HAX1 after SCI. The results of western blot indicated that HAX1 was present in sham operated control group and significantly elevated at 3 days post SCI, then declined gradually. Immunohistochemical studies indicated HAX1 expression was enhanced significantly in white and gray matter at 3 days post SCI compared with sham operated group. Double immunofluorescence staining showed the proportion of cells, double-labeled HAX1 and neurons, astrocytes, increased significantly at 3 days post SCI. In addition, co-localization of HAX1/active caspase-3 and HAX1/PCNA was tested in cells. Furthermore, over-expression of HAX1 inhibited neuronal apoptosis in vitro, and in astrocytes HAX1 silencing could down-regulate PCNA expression post LPS treatment. Meanwhile, CCK8 assay showed that knockdown of HAX1 could inhibit the astrocyte proliferation. In summary, our data indicated that HAX1 might play significant roles in pathological process of neuronal apoptosis and astrocyte proliferation during SCI.
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Affiliation(s)
- Xiongsong Lu
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, Haier Lane North Road No. 6, Nantong, 226001, Jiangsu, People's Republic of China; Medical College, Nantong University, Jiangsu, People's Republic of China
| | - Pengfei Xue
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, Haier Lane North Road No. 6, Nantong, 226001, Jiangsu, People's Republic of China
| | - Luyu Fu
- Department of Pathophysiology, Medical College, Nantong University, Jiangsu, People's Republic of China
| | - Jinlong Zhang
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, Haier Lane North Road No. 6, Nantong, 226001, Jiangsu, People's Republic of China
| | - Jiawei Jiang
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, Haier Lane North Road No. 6, Nantong, 226001, Jiangsu, People's Republic of China
| | - Xiaofeng Guo
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, Haier Lane North Road No. 6, Nantong, 226001, Jiangsu, People's Republic of China
| | - Guofeng Bao
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, Haier Lane North Road No. 6, Nantong, 226001, Jiangsu, People's Republic of China
| | - Guanhua Xu
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, Haier Lane North Road No. 6, Nantong, 226001, Jiangsu, People's Republic of China
| | - Yuyu Sun
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, Haier Lane North Road No. 6, Nantong, 226001, Jiangsu, People's Republic of China
| | - Jiajia Chen
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, Haier Lane North Road No. 6, Nantong, 226001, Jiangsu, People's Republic of China.
| | - Zhiming Cui
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, Haier Lane North Road No. 6, Nantong, 226001, Jiangsu, People's Republic of China.
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12
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Enhanced effect of VEGF165 on L-type calcium currents in guinea-pig cardiac ventricular myocytes. Biomed Pharmacother 2017; 85:697-703. [DOI: 10.1016/j.biopha.2016.11.082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/09/2016] [Accepted: 11/18/2016] [Indexed: 02/08/2023] Open
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Singh U, Bernstein JA, Haar L, Luther K, Jones WK. Azelastine desensitization of transient receptor potential vanilloid 1: a potential mechanism explaining its therapeutic effect in nonallergic rhinitis. Am J Rhinol Allergy 2015; 28:215-24. [PMID: 24980233 DOI: 10.2500/ajra.2014.28.4059] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Capsaicin, a prototypic transient receptor potential vanilloid 1 (TRPV1) agonist, has been shown to be more clinically effective in the treatment of nonallergic rhinitis (NAR) compared with other rhinitis subtypes. Azelastine has also been found to be clinically effective in the treatment of NAR but its mechanism(s) of action is still poorly elucidated. This study was designed to determine, using in vitro cell lines, whether topical therapies including azelastine have activity on TRPV1 ion channels similar to capsaicin. METHODS The effects of capsaicin (1 μM), azelastine (30 μM), bepotastine (10 μM), olopatadine (10 μM), and fluticasone (200 μM) on TRPV1 channels using mice neuronal cells (Cath.a), as surrogates for submucosal sensory neurons, and human nasal epithelial cells (hNEC) were determined and compared. For azelastine, bepotastine, and capsaicin, which elicited an agonist effect on TRPV1, live cell [Ca(2+)] signaling in Cath.a cells and hNECs expressing TRPV1 were performed in the absence and presence of capsazepine at 10 μM (a TRPV1 antagonist) or using wild-type mouse embryonic fibroblasts (wtMEFs) that express TRPV1 ion channels and TRPV1 homozygous null mutant (TRPV1-/-) knockout MEF cells as controls to establish TRPV1 channel selectivity. As azelastine has previously been found clinically effective in NAR, additional experiments were performed to determine its ability to desensitize TRPV1 ion channels and its effect on regulating intracellular calcium homeostasis. RESULTS Cath.a cells treated with azelastine, bepotastine, or capsaicin showed a significant increase in TRPV1-dependant (Ca(2+)) specific cytosolic fluorescence. Continuous treatment with azelastine or capsaicin resulted in desensitization of TRPV1 channels. In hNECs, azelastine stimulation resulted in Ca(2+) shifts from the cytosol to mitochondria and overexpression of hematopoietic cell-specific Lyn substrate 1-associated protein X1, which may thus be effective in cytosolic Ca(2+) homeostasis. CONCLUSION Azelastine, similar to capsaicin, exhibits direct activity on TRPV1 ion channels that may represent a novel mechanistic pathway explaining its clinical efficacy in NAR.
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Affiliation(s)
- Umesh Singh
- Division of Allergy Section, College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
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14
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Truszkowska GT, Bilińska ZT, Kosińska J, Śleszycka J, Rydzanicz M, Sobieszczańska-Małek M, Franaszczyk M, Bilińska M, Stawiński P, Michalak E, Małek ŁA, Chmielewski P, Foss-Nieradko B, Machnicki MM, Stokłosa T, Ponińska J, Szumowski Ł, Grzybowski J, Piwoński J, Drygas W, Zieliński T, Płoski R. A study in Polish patients with cardiomyopathy emphasizes pathogenicity of phospholamban (PLN) mutations at amino acid position 9 and low penetrance of heterozygous null PLN mutations. BMC MEDICAL GENETICS 2015; 16:21. [PMID: 25928149 PMCID: PMC4421997 DOI: 10.1186/s12881-015-0167-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 03/23/2015] [Indexed: 12/16/2022]
Abstract
Background In humans mutations in the PLN gene, encoding phospholamban - a regulator of sarcoplasmic reticulum calcium ATPase (SERCA), cause cardiomyopathy with prevalence depending on the population. Our purpose was to identify PLN mutations in Polish cardiomyopathy patients. Methods We studied 161 unrelated subjects referred for genetic testing for cardiomyopathies: 135 with dilated cardiomyopathy, 22 with hypertrophic cardiomyopathy and 4 with other cardiomyopathies. In 23 subjects multiple genes were sequenced by next generation sequencing and in all subjects PLN exons were analyzed by Sanger sequencing. Control group included 200 healthy subjects matched with patients for ethnicity, sex and age. Large deletions/insertions were screened by real time polymerase chain reaction. Results We detected three different heterozygous mutations in the PLN gene: a novel null c.9_10insA:(p.Val4Serfs*15) variant and two missense variants: c.25C > T:(p.Arg9Cys) and c.26G > T:(p.Arg9Leu). The (p.Val4Serfs*15) variant occurred in the patient with Wolff-Parkinson-White syndrome in whom the diagnosis of cardiomyopathy was not confirmed and his mother who had concentric left ventricular remodeling but normal left ventricular mass and function. We did not detect large deletions/insertions in PLN in cohort studied. Conclusions In Poland, similar to most populations, PLN mutations rarely cause cardiomyopathy. The 9thPLN residue is apparently a mutation hot spot whereas a single dose of c.9_10insA, and likely other null PLN mutations, cause the disease only with low penetrance or are not pathogenic. Electronic supplementary material The online version of this article (doi:10.1186/s12881-015-0167-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Grażyna T Truszkowska
- Laboratory of Molecular Biology, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Zofia T Bilińska
- Unit for Screening Studies in Inherited Cardiovascular Diseases, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Joanna Kosińska
- Department of Medical Genetics, Warsaw Medical University, ul. Pawińskiego 3C, 02-106, Warszawa, Poland.
| | - Justyna Śleszycka
- Department of Cardiomyopathies, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Małgorzata Rydzanicz
- Department of Medical Genetics, Warsaw Medical University, ul. Pawińskiego 3C, 02-106, Warszawa, Poland.
| | | | - Maria Franaszczyk
- Laboratory of Molecular Biology, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Maria Bilińska
- Department of Arrhythmia, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Piotr Stawiński
- Department of Immunology, Center for Biostructure Research, Medical University of Warsaw, Warszawa, Poland.
| | - Ewa Michalak
- Unit for Screening Studies in Inherited Cardiovascular Diseases, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Łukasz A Małek
- Department of Interventional Cardiology and Angiology, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Przemysław Chmielewski
- Unit for Screening Studies in Inherited Cardiovascular Diseases, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Bogna Foss-Nieradko
- Unit for Screening Studies in Inherited Cardiovascular Diseases, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Marcin M Machnicki
- Department of Immunology, Center for Biostructure Research, Medical University of Warsaw, Warszawa, Poland.
| | - Tomasz Stokłosa
- Department of Immunology, Center for Biostructure Research, Medical University of Warsaw, Warszawa, Poland.
| | - Joanna Ponińska
- Laboratory of Molecular Biology, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Łukasz Szumowski
- Department of Arrhythmia, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Jacek Grzybowski
- Department of Cardiomyopathies, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Jerzy Piwoński
- Department of Epidemiology, Cardiovascular Diseases Prevention and Promotion of Health, Institute of Cardiology, ul. Niemodlińska 33, 04-635, Warszawa, Poland.
| | - Wojciech Drygas
- Department of Epidemiology, Cardiovascular Diseases Prevention and Promotion of Health, Institute of Cardiology, ul. Niemodlińska 33, 04-635, Warszawa, Poland.
| | - Tomasz Zieliński
- Department of Heart Failure and Transplantology, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Rafał Płoski
- Department of Medical Genetics, Warsaw Medical University, ul. Pawińskiego 3C, 02-106, Warszawa, Poland.
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Shemarova IV, Nesterov VP. Evolution of Ca2+-signaling mechanisms: The role of Ca2+ in regulation of specialized cardiomyocyte functions in chronic heart diseases. J EVOL BIOCHEM PHYS+ 2015. [DOI: 10.1134/s0022093014060027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Echinochrome A regulates phosphorylation of phospholamban Ser16 and Thr17 suppressing cardiac SERCA2A Ca²⁺ reuptake. Pflugers Arch 2014; 467:2151-63. [PMID: 25410495 DOI: 10.1007/s00424-014-1648-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 10/24/2014] [Accepted: 11/04/2014] [Indexed: 02/05/2023]
Abstract
Echinochrome A (Ech A), a marine bio-product isolated from sea urchin eggs, is known to have cardioprotective effects through its strong antioxidant and ATP-sparing capabilities. However, the effects of Ech A on cardiac excitation-contraction (E-C) are not known. In this study, we investigated the effects of Ech A on cardiac contractility and Ca(2+) handling in the rat heart. In ex vivo Langendorff hearts, Ech A (3 μM) decreased left ventricular developing pressure to 77.7 ± 6.5 % of basal level. In isolated ventricular myocytes, Ech A reduced the fractional cell shortening from 3.4 % at baseline to 2.1 %. Ech A increased both diastolic and peak systolic intracellular Ca(2+) ([Ca(2+)]i). However, the ratio of peak [Ca]i to resting [Ca]i was significantly decreased. Ech A did not affect the L-type Ca(2+) current. Inhibiting the Na(+)/Ca(2+) exchanger with either NiCl2 or SEA400 did not affect the Ech A-dependent changes in Ca(2+) handling. Our data demonstrate that treatment with Ech A results in a significant reduction in the phosphorylation of phospholamban at both serine 16 and threonine 17 leading to a significant inhibition of SR Ca(2+)-ATPase 2A (SERCA2A) and subsequent reduced Ca(2+) uptake into the intracellular Ca(2+) store. Taken together, our data show that Ech A negatively regulates cardiac contractility by inhibiting SERCA2A activity, which leads to a reduction in internal Ca(2+) stores.
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Koontz J, Kontrogianni-Konstantopoulos A. Competition through dimerization between antiapoptotic and proapoptotic HS-1-associated protein X-1 (Hax-1). J Biol Chem 2013; 289:3468-77. [PMID: 24347163 DOI: 10.1074/jbc.m113.536151] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Studies on Hax-1 have mainly focused on variant (v) 1, demonstrating its antiapoptotic properties. However, HAX1 is heavily spliced, generating structurally distinct isoforms. We sought to characterize the Hax-1 isoforms expressed in rat heart before and after insult. We confirmed the presence of at least four Hax-1 transcripts in healthy rat cardiac muscle. These exhibited differential expression before and after induction of myocardial infarction, with v2 being up-regulated 12-fold at the transcript level and 1.5-fold at the protein level post-insult. Contrary to antiapoptotic rat and human v1, overexpression of rat v2 or human v4 (the human homologue of rat v2) in epithelial cells exacerbated cell death by 30% following H2O2 treatment compared with control vector. Coexpression of rat v1 and v2 or human v1 and v4 neutralized the protective effects of rat and human v1 and the proapoptotic effects of rat v2 and human v4 by modulating cytochrome c release. This is, at least partly, mediated by the ability of Hax-1 proteins to form homotypic and heterotypic dimers with binding affinities ranging from ~3.8 nm for v1 dimers to ~97 nm for v1/v2 dimers. The minimal binding region supporting these interactions lies between amino acids 97-278, which are shared by nearly all Hax-1 proteins, indicating that additional factors regulate the preferential formation of Hax-1 homo- or heterodimers. Our studies are the first to show that Hax-1 is a family of anti- and proapoptotic regulators that may modulate cell survival and death through homo- or heterodimerization.
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Affiliation(s)
- Jason Koontz
- From the Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201
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18
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Glembotski CC. Roles for the sarco-/endoplasmic reticulum in cardiac myocyte contraction, protein synthesis, and protein quality control. Physiology (Bethesda) 2013; 27:343-50. [PMID: 23223628 DOI: 10.1152/physiol.00034.2012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Although the function of the sarcoplasmic/endoplasmic reticulum (SR/ER) in cardiac contractile calcium handling is well established, its roles in protein synthesis, folding, and quality control in cardiac myocytes are not as clear. This review explores evidence suggesting that, in cardiac myocytes, protein synthesis and contractile calcium handling may be physically and functionally integrated.
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Affiliation(s)
- Christopher C Glembotski
- San Diego State University Heart Institute and the Department of Biology, San Diego State University, San Diego, California, USA.
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Sivakumaran V, Stanley BA, Tocchetti CG, Ballin JD, Caceres V, Zhou L, Keceli G, Rainer PP, Lee DI, Huke S, Ziolo MT, Kranias EG, Toscano JP, Wilson GM, O'Rourke B, Kass DA, Mahaney JE, Paolocci N. HNO enhances SERCA2a activity and cardiomyocyte function by promoting redox-dependent phospholamban oligomerization. Antioxid Redox Signal 2013; 19:1185-97. [PMID: 23919584 PMCID: PMC3785857 DOI: 10.1089/ars.2012.5057] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AIMS Nitroxyl (HNO) interacts with thiols to act as a redox-sensitive modulator of protein function. It enhances sarcoplasmic reticular Ca(2+) uptake and myofilament Ca(2+) sensitivity, improving cardiac contractility. This activity has led to clinical testing of HNO donors for heart failure. Here we tested whether HNO alters the inhibitory interaction between phospholamban (PLN) and the sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a) in a redox-dependent manner, improving Ca(2+) handling in isolated myocytes/hearts. RESULTS Ventriculocytes, sarcoplasmic reticulum (SR) vesicles, and whole hearts were isolated from control (wildtype [WT]) or PLN knockout (pln(-/-)) mice. Compared to WT, pln(-/-) myocytes displayed enhanced resting sarcomere shortening, peak Ca(2+) transient, and blunted β-adrenergic responsiveness. HNO stimulated shortening, relaxation, and Ca(2+) transient in WT cardiomyocytes, and evoked positive inotropy/lusitropy in intact hearts. These changes were markedly blunted in pln(-/-) cells/hearts. HNO enhanced SR Ca(2+) uptake in WT but not pln(-/-) SR-vesicles. Spectroscopic studies in insect cell microsomes expressing SERCA2a±PLN showed that HNO increased Ca(2+)-dependent SERCA2a conformational flexibility but only when PLN was present. In cardiomyocytes, HNO achieved this effect by stabilizing PLN in an oligomeric disulfide bond-dependent configuration, decreasing the amount of free inhibitory monomeric PLN available. INNOVATION HNO-dependent redox changes in myocyte PLN oligomerization relieve PLN inhibition of SERCA2a. CONCLUSIONS PLN plays a central role in HNO-induced enhancement of SERCA2a activity, leading to increased inotropy/lusitropy in intact myocytes and hearts. PLN remains physically associated with SERCA2a; however, less monomeric PLN is available resulting in decreased inhibition of the enzyme. These findings offer new avenues to improve Ca(2+) handling in failing hearts.
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Affiliation(s)
- Vidhya Sivakumaran
- 1 Division of Cardiology, Johns Hopkins Medical Institutions , Baltimore, Maryland
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Lam CK, Zhao W, Cai W, Vafiadaki E, Florea SM, Ren X, Liu Y, Robbins N, Zhang Z, Zhou X, Jiang M, Rubinstein J, Jones WK, Kranias EG. Novel role of HAX-1 in ischemic injury protection involvement of heat shock protein 90. Circ Res 2012; 112:79-89. [PMID: 22982986 DOI: 10.1161/circresaha.112.279935] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
RATIONALE Ischemic heart disease is characterized by contractile dysfunction and increased cardiomyocyte death, induced by necrosis and apoptosis. Increased cell survival after an ischemic insult is critical and depends on several cellular pathways, which have not been fully elucidated. OBJECTIVE To test the hypothesis that the anti-apoptotic hematopoietic lineage substrate-1-associated protein X-1 (HAX-1), recently identified as regulator of cardiac Ca cycling, also may ameliorate cellular injury with an ischemic insult. METHODS AND RESULTS We report that cardiac ischemia/reperfusion injury is associated with significant decreases in HAX-1 levels ex vivo and in vivo. Accordingly, overexpression of HAX-1 improved contractile recovery, coupled with reduced infarct size, plasma troponin I level, and apoptosis. The beneficial effects were associated with decreased endoplasmic reticulum (ER) stress response through specific inhibition of the inositol-requiring enzyme (IRE-1) signaling pathway, including its downstream effectors caspase-12 and the transcription factor C/EBP homologous protein. Conversely, HAX-1 heterozygous-deficient hearts exhibited increases in infarct size and IRE-1 activity. The inhibitory effects of HAX-1 were mediated by its binding to the N-terminal fragment of the heat shock protein 90 (Hsp90). Moreover, HAX-1 sequestered Hsp90 from IRE-1 to the phospholamban-sarcoplasmic/endoplasmic reticulum calcium ATPase complex. The HAX-1 regulation was further supported by loss of IRE-1 inhibition in presence of the Hsp90 inhibitor, 17-N-allylamino-17-demethoxygeldanamycin. CONCLUSIONS Cardiac ischemia-reperfusion injury is associated with decreases in HAX-1 levels. Consequently, overexpression of HAX-1 promotes cardiomyocyte survival, mediated by its interaction with Hsp90 and specific inhibition of IRE-1 signaling at the ER/sarcoplasmic reticulum.
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Affiliation(s)
- Chi Keung Lam
- Department of Pharmacology & Cell Biophysics, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
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Aschar-Sobbi R, Emmett TL, Kargacin GJ, Kargacin ME. Phospholamban phosphorylation increases the passive calcium leak from cardiac sarcoplasmic reticulum. Pflugers Arch 2012; 464:295-305. [DOI: 10.1007/s00424-012-1124-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 05/16/2012] [Accepted: 06/05/2012] [Indexed: 01/28/2023]
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Ginkgo biloba extract EGB761 protects against aging-associated diastolic dysfunction in cardiomyocytes of D-galactose-induced aging rat. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:418748. [PMID: 22693651 PMCID: PMC3368694 DOI: 10.1155/2012/418748] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 03/06/2012] [Accepted: 03/13/2012] [Indexed: 11/18/2022]
Abstract
The aim of the present study was to make use of the artificially induced aging model cardiomyocytes to further investigate potential anti-aging-associated cellular diastolic dysfunction effects of EGB761 and explore underlying molecular mechanisms. Cultured rat primary cardiomyocytes were treated with either D-galactose or D-galactose combined with EGB761 for 48 h. After treatment, the percentage of cells positive for SA-β-gal, AGEs production, cardiac sarcoplasmic reticulum calcium pump (SERCA) activity, the myocardial sarcoplasmic reticulum calcium uptake, and relative protein levels were measured. Our results demonstrated that in vitro stimulation with D-galactose induced AGEs production. The addition of EGB761 significantly decreased the number of cells positive for SA-β-gal. Furthermore, decreased diastolic [Ca2+]i, curtailment of the time from the maximum concentration of Ca2+ to the baseline level and increased reuptake of Ca2+ stores in the SR were also observed. In addition, the level of p-Ser16-PLN protein as well as SERCA was markedly increased. The study indicated that EGb761 alleviates formation of AGEs products on SERCA2a in order to mitigate myocardial stiffness on one hand; on other hand, improve SERCA2a function through increase the amount of Ser16 sites PLN phosphorylation, which two hands finally led to ameliorate diastolic dysfunction of aging cardiomyocytes.
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Mazzio EA, Boukli N, Rivera N, Soliman KFA. Pericellular pH homeostasis is a primary function of the Warburg effect: inversion of metabolic systems to control lactate steady state in tumor cells. Cancer Sci 2012; 103:422-32. [PMID: 22320183 DOI: 10.1111/j.1349-7006.2012.02206.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 11/22/2011] [Accepted: 12/08/2011] [Indexed: 12/25/2022] Open
Abstract
The Warburg effect describes a heightened propensity of tumor cells to produce lactic acid in the presence or absence of O(2) . A generally held notion is that the Warburg effect is related to energy. Using whole-genome, proteomic MALDI-TOF-MS and metabolite analysis, we investigated the Warburg effect in malignant neuroblastoma N2a cells. The findings show that the Warburg effect serves a functional role in regulating acidic pericellular pH (pHe), which is mediated by metabolic inversion or a fluctuating dominance between glycolytic-rate substrate level phosphorylation (SLP) and mitochondrial (mt) oxidative phosphorylation (OXPHOS) to control lactic acid production. The results also show that an alkaline pHe caused an elevation in SLP/OXPHOS ratio (approximately 98% SLP/OXPHOS); while the ratio was approximately 56% at neutral pHe and approximately 93% in acidic pHe. Acidic pHe paralleled greater expression of mitochondrial biogenesis and OXPHOS genes, such as complex III-V (Uqcr10, Atp5 and Cox7c), mt Fmc1, Romo1, Tmem 173, Tomm6, aldehyde dehydrogenase, mt Sod2 mt biogenesis component PPAR-γ co-activator 1 adjunct to loss of mt fission (Mff). Moreover, acidic pHe corresponded to metabolic efficiency evidenced by a rise in mTOR nutrient sensor GβL, its downstream target (Eif4ebp1), insulin modulators (Trib3 and Fetub) and loss of catabolic (Hadhb, Bdh1 and Pygl)/glycolytic processes (aldolase C, pyruvate kinase, Nampt and aldose-reductase). In contrast, alkaline pHe initiated loss of mitofusin 2, complex II-IV (Sdhaf1, Uqcrq, Cox4i2 and Aldh1l2), aconitase, mitochondrial carrier triple repeat 1 and mt biosynthetic (Coq2, Coq5 and Coq9). In conclusion, the Warburg effect might serve as a negative feedback loop that regulates the pHe toward a broad acidic range by altering lactic acid production through inversion of metabolic systems. These effects were independent of changes in O(2) concentration or glucose supply.
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Affiliation(s)
- Elizabeth A Mazzio
- College of Pharmacy and Pharmaceutical Sciences, Florida A & M University, Tallahassee, Florida, USA
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Vandecaetsbeek I, Vangheluwe P, Raeymaekers L, Wuytack F, Vanoevelen J. The Ca2+ pumps of the endoplasmic reticulum and Golgi apparatus. Cold Spring Harb Perspect Biol 2011; 3:cshperspect.a004184. [PMID: 21441596 DOI: 10.1101/cshperspect.a004184] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The various splice variants of the three SERCA- and the two SPCA-pump genes in higher vertebrates encode P-type ATPases of the P(2A) group found respectively in the membranes of the endoplasmic reticulum and the secretory pathway. Of these, SERCA2b and SPCA1a represent the housekeeping isoforms. The SERCA2b form is characterized by a luminal carboxy terminus imposing a higher affinity for cytosolic Ca(2+) compared to the other SERCAs. This is mediated by intramembrane and luminal interactions of this extension with the pump. Other known affinity modulators like phospholamban and sarcolipin decrease the affinity for Ca(2+). The number of proteins reported to interact with SERCA is rapidly growing. Here, we limit the discussion to those for which the interaction site with the ATPase is specified: HAX-1, calumenin, histidine-rich Ca(2+)-binding protein, and indirectly calreticulin, calnexin, and ERp57. The role of the phylogenetically older and structurally simpler SPCAs as transporters of Ca(2+), but also of Mn(2+), is also addressed.
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Affiliation(s)
- Ilse Vandecaetsbeek
- Laboratory of Ca-transport ATPases, Department of Molecular Cell Biology, K.U. Leuven, Leuven, Belgium
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Boursiac Y, Lee SM, Romanowsky S, Blank R, Sladek C, Chung WS, Harper JF. Disruption of the vacuolar calcium-ATPases in Arabidopsis results in the activation of a salicylic acid-dependent programmed cell death pathway. PLANT PHYSIOLOGY 2010; 154:1158-71. [PMID: 20837703 PMCID: PMC2971596 DOI: 10.1104/pp.110.159038] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Accepted: 09/09/2010] [Indexed: 05/18/2023]
Abstract
Calcium (Ca(2+)) signals regulate many aspects of plant development, including a programmed cell death pathway that protects plants from pathogens (hypersensitive response). Cytosolic Ca(2+) signals result from a combined action of Ca(2+) influx through channels and Ca(2+) efflux through pumps and cotransporters. Plants utilize calmodulin-activated Ca(2+) pumps (autoinhibited Ca(2+)-ATPase [ACA]) at the plasma membrane, endoplasmic reticulum, and vacuole. Here, we show that a double knockout mutation of the vacuolar Ca(2+) pumps ACA4 and ACA11 in Arabidopsis (Arabidopsis thaliana) results in a high frequency of hypersensitive response-like lesions. The appearance of macrolesions could be suppressed by growing plants with increased levels (greater than 15 mm) of various anions, providing a method for conditional suppression. By removing plants from a conditional suppression, lesion initials were found to originate primarily in leaf mesophyll cells, as detected by aniline blue staining. Initiation and spread of lesions could also be suppressed by disrupting the production or accumulation of salicylic acid (SA), as shown by combining aca4/11 mutations with a sid 2 (for salicylic acid induction-deficient2) mutation or expression of the SA degradation enzyme NahG. This indicates that the loss of the vacuolar Ca(2+) pumps by itself does not cause a catastrophic defect in ion homeostasis but rather potentiates the activation of a SA-dependent programmed cell death pathway. Together, these results provide evidence linking the activity of the vacuolar Ca(2+) pumps to the control of a SA-dependent programmed cell death pathway in plants.
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Kokoszyńska K, Rychlewski L, Wyrwicz LS. Distant homologs of anti-apoptotic factor HAX1 encode parvalbumin-like calcium binding proteins. BMC Res Notes 2010; 3:197. [PMID: 20633251 PMCID: PMC2914655 DOI: 10.1186/1756-0500-3-197] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Accepted: 07/15/2010] [Indexed: 12/02/2022] Open
Abstract
Background Apoptosis is a highly ordered and orchestrated multiphase process controlled by the numerous cellular and extra-cellular signals, which executes the programmed cell death via release of cytochrome c alterations in calcium signaling, caspase-dependent limited proteolysis and DNA fragmentation. Besides the general modifiers of apoptosis, several tissue-specific regulators of this process were identified including HAX1 (HS-1 associated protein X-1) - an anti-apoptotic factor active in myeloid cells. Although HAX1 was the subject of various experimental studies, the mechanisms of its action and a functional link connected with the regulation of apoptosis still remains highly speculative. Findings Here we provide the data which suggests that HAX1 may act as a regulator or as a sensor of calcium. On the basis of iterative similarity searches, we identified a set of distant homologs of HAX1 in insects. The applied fold recognition protocol gives us strong evidence that the distant insects' homologs of HAX1 are novel parvalbumin-like calcium binding proteins. Although the whole three EF-hands fold is not preserved in vertebrate our analysis suggests that there is an existence of a potential single EF-hand calcium binding site in HAX1. The molecular mechanism of its action remains to be identified, but the risen hypothesis easily translates into previously reported lines of various data on the HAX1 biology as well as, provides us a direct link to the regulation of apoptosis. Moreover, we also report that other family of myeloid specific apoptosis regulators - myeloid leukemia factors (MLF1, MLF2) share the homologous C-terminal domain and taxonomic distribution with HAX1. Conclusions Performed structural and active sites analyses gave new insights into mechanisms of HAX1 and MLF families in apoptosis process and suggested possible role of HAX1 in calcium-binding, still the analyses require further experimental verification.
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Affiliation(s)
- Katarzyna Kokoszyńska
- Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Roentgena 5, 02-781 Warsaw, Poland.
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Eyster KM, Hansen KA, Winterton E, Klinkova O, Drappeau D, Mark-Kappeler CJ. Reciprocal communication between endometrial stromal cells and macrophages. Reprod Sci 2010; 17:809-22. [PMID: 20601541 DOI: 10.1177/1933719110371854] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
This study tested the hypothesis that reciprocal communication occurs between macrophages and cultured human endometrial stromal cells and that this communication may contribute to the pathology of endometriosis. An endometrial stromal cell line (telomerase-immortalized human endometrial stromal cell [T-HESC]) was treated with macrophage-conditioned medium (CM) +/- estradiol + progesterone. Macrophages were treated without or with T-HESC CM. DNA microarray identified 716 differentially expressed genes in T-HESCs in response to factors secreted by macrophages. Upregulated genes in T-HESC included interleukin 8 (IL-8)/chemokine (C-X-C motif) ligand 8 (CXCL8), matrix metalloproteinase 3 (MMP3), phospholamban, cysteine-rich angiogenic inducer 61 (CYR61), connective tissue growth factor (CTGF), tenascin C, and nicotinamide N-methyltransferase (NNMT), whereas integrin alpha-6 was downregulated. In contrast, 15 named genes were differentially expressed in macrophages in response to factors secreted by endometrial stromal cells. The data document reciprocal communication between macrophages and endometrial stromal cells and suggest that interaction with macrophages stimulates the expression of genes in endometrial stromal cells that may support the establishment of endometriosis.
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Affiliation(s)
- Kathleen M Eyster
- Division of Basic Biomedical Sciences, Sanford School of Medicine of the University of South Dakota, Vermillion, SD 57069, USA.
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Yap SV, Vafiadaki E, Strong J, Kontrogianni-Konstantopoulos A. HAX-1: a multifaceted antiapoptotic protein localizing in the mitochondria and the sarcoplasmic reticulum of striated muscle cells. J Mol Cell Cardiol 2009; 48:1266-79. [PMID: 19913549 DOI: 10.1016/j.yjmcc.2009.10.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 10/23/2009] [Accepted: 10/30/2009] [Indexed: 11/27/2022]
Abstract
HAX-1 comprises a family of ubiquitously expressed proteins with antiapoptotic properties. In the current study, we investigated HAX-1's temporospatial distribution in rat striated muscles during development and in adulthood. In cardiocytes, HAX-1 is organized at the level of Z-disks throughout embryogenesis and adulthood; however, in skeletal myofibers, it is in register with M-bands during embryonic and early postnatal life and Z-disks during late postnatal and adult life. Immunoelectron microscopy and subcellular fractionation demonstrated that HAX-1 proteins localize at the mitochondrial and sarcoplasmic reticulum (SR) membranes, as well as at sites where the two are closely apposed. Variants I and II selectively concentrate in the mitochondrial membranes, whereas variants III, IV, and V localize in both organelles, albeit to varying extents. Deletion analysis combined with cellular transfections indicated that elimination of HAX-1's NH(2)-terminus abolishes its mitochondrial targeting and attenuates its antiapoptotic capacity, while removal of its binding site for the SR protein phospholamban (PLN) prevents its translocation to the SR. Consistent with this, HAX-1 is preferentially lost from the SR of PLN-deficient hearts. Our findings are the first to present a comprehensive characterization of HAX-1's expression in striated muscles and to provide insights on the mechanisms through which it may modulate apoptosis.
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Affiliation(s)
- Solomon V Yap
- University of Maryland, School of Medicine, Department of Biochemistry and Molecular Biology, Baltimore, MD 21201, USA
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Vandecaetsbeek I, Raeymaekers L, Wuytack F, Vangheluwe P. Factors controlling the activity of the SERCA2a pump in the normal and failing heart. Biofactors 2009; 35:484-99. [PMID: 19904717 DOI: 10.1002/biof.63] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Heart failure is the leading cause of death in western countries and is often associated with impaired Ca(2+) handling in the cardiomyocyte. In fact, cardiomyocyte relaxation and contraction are tightly controlled by the activity of the cardiac sarco(endo)plasmic reticulum (ER/SR) Ca(2+) pump SERCA2a, pumping Ca(2+) from the cytosol into the lumen of the ER/SR. This review addresses three important facets that control the SERCA2 activity in the heart. First, we focus on the alternative splicing of the SERCA2 messenger, which is strictly regulated in the developing heart. This splicing controls the formation of three SERCA2 splice variants with different enzymatic properties. Second, we will discuss the role and regulation of SERCA2a activity in the normal and failing heart. The two well-studied Ca(2+) affinity modulators phospholamban and sarcolipin control the activity of SERCA2a within a narrow window. An aberrantly high or low Ca(2+) affinity is often observed in and may even trigger cardiac failure. Correcting SERCA2a activity might therefore constitute a therapeutic approach to improve the contractility of the failing heart. Finally, we address the controversies and unanswered questions of other putative regulators of the cardiac Ca(2+) pump, such as sarcalumenin, HRC, S100A1, Bcl-2, HAX-1, calreticulin, calnexin, ERp57, IRS-1, and -2.
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Affiliation(s)
- Ilse Vandecaetsbeek
- Department of Molecular Cell Biology, Laboratory of Ca(2+)-transport ATPases, K.U.Leuven, Leuven, Belgium
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Fadeel B, Grzybowska E. HAX-1: a multifunctional protein with emerging roles in human disease. Biochim Biophys Acta Gen Subj 2009; 1790:1139-48. [PMID: 19524642 DOI: 10.1016/j.bbagen.2009.06.004] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 05/31/2009] [Accepted: 06/06/2009] [Indexed: 11/25/2022]
Abstract
HS-1-associated protein X-1 (HAX-1) was identified more than 10 years ago as a novel protein with ubiquitous tissue expression and a predominantly mitochondrial localization at the subcellular level. Recent studies have shown that homozygous mutations in the HAX1 gene are associated with autosomal recessive forms of severe congenital neutropenia (also known as Kostmann disease), and results from studies in mice and men are beginning to unravel a prominent role for HAX-1 in apoptosis signaling not only in the hematopoietic compartment, but also in the central nervous system. Moreover, several different cellular and viral binding partners of HAX-1 have been identified thus pointing toward a complex and multifunctional role of this protein. HAX-1 has also been shown to bind to the 3' untranslated regions of certain mRNAs and could therefore contribute to the regulation of transport and/or stability of such transcripts. The present review discusses the emerging and divergent roles of HAX-1, including its involvement in cell migration, apoptosis signaling, and mRNA surveillance. The importance of HAX-1 in human disease is also highlighted and outstanding questions that remain to be addressed are identified.
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Affiliation(s)
- Bengt Fadeel
- Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden.
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Vafiadaki E, Arvanitis DA, Pagakis SN, Papalouka V, Sanoudou D, Kontrogianni-Konstantopoulos A, Kranias EG. The anti-apoptotic protein HAX-1 interacts with SERCA2 and regulates its protein levels to promote cell survival. Mol Biol Cell 2008; 20:306-18. [PMID: 18971376 DOI: 10.1091/mbc.e08-06-0587] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Cardiac contractility is regulated through the activity of various key Ca(2+)-handling proteins. The sarco(endo)plasmic reticulum (SR) Ca(2+) transport ATPase (SERCA2a) and its inhibitor phospholamban (PLN) control the uptake of Ca(2+) by SR membranes during relaxation. Recently, the antiapoptotic HS-1-associated protein X-1 (HAX-1) was identified as a binding partner of PLN, and this interaction was postulated to regulate cell apoptosis. In the current study, we determined that HAX-1 can also bind to SERCA2. Deletion mapping analysis demonstrated that amino acid residues 575-594 of SERCA2's nucleotide binding domain are required for its interaction with the C-terminal domain of HAX-1, containing amino acids 203-245. In transiently cotransfected human embryonic kidney 293 cells, recombinant SERCA2 was specifically targeted to the ER, whereas HAX-1 selectively concentrated at mitochondria. On triple transfections with PLN, however, HAX-1 massively translocated to the ER membranes, where it codistributed with PLN and SERCA2. Overexpression of SERCA2 abrogated the protective effects of HAX-1 on cell survival, after hypoxia/reoxygenation or thapsigargin treatment. Importantly, HAX-1 overexpression was associated with down-regulation of SERCA2 expression levels, resulting in significant reduction of apparent ER Ca(2+) levels. These findings suggest that HAX-1 may promote cell survival through modulation of SERCA2 protein levels and thus ER Ca(2+) stores.
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Affiliation(s)
- Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Greece
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