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Rao K, Rochon E, Singh A, Jagannathan R, Peng Z, Mansoor H, Wang B, Moulik M, Zhang M, Saraf A, Corti P, Shiva S. Myoglobin modulates the Hippo pathway to promote cardiomyocyte differentiation. iScience 2024; 27:109146. [PMID: 38414852 PMCID: PMC10897895 DOI: 10.1016/j.isci.2024.109146] [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: 01/28/2023] [Revised: 09/30/2023] [Accepted: 02/01/2024] [Indexed: 02/29/2024] Open
Abstract
The endogenous mechanisms that propagate cardiomyocyte differentiation and prevent de-differentiation remain unclear. While the expression of the heme protein myoglobin increases by over 50% during cardiomyocyte differentiation, a role for myoglobin in regulating cardiomyocyte differentiation has not been tested. Here, we show that deletion of myoglobin in cardiomyocyte models decreases the gene expression of differentiation markers and stimulates cellular proliferation, consistent with cardiomyocyte de-differentiation. Mechanistically, the heme prosthetic group of myoglobin catalyzes the oxidation of the Hippo pathway kinase LATS1, resulting in phosphorylation and inactivation of yes-associated protein (YAP). In vivo, myoglobin-deficient zebrafish hearts show YAP dephosphorylation and accelerated cardiac regeneration after apical injury. Similarly, myoglobin knockdown in neonatal murine hearts shows increased YAP dephosphorylation and cardiomyocyte cycling. These data demonstrate a novel role for myoglobin as an endogenous driver of cardiomyocyte differentiation and highlight myoglobin as a potential target to enhance cardiac development and improve cardiac repair and regeneration.
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Affiliation(s)
- Krithika Rao
- Heart, Lung, Blood Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Elizabeth Rochon
- Heart, Lung, Blood Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Anuradha Singh
- Heart, Lung, Blood Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Rajaganapathi Jagannathan
- Heart, Lung, Blood Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Division of Cardiology, Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Zishan Peng
- Division of Cardiology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Haris Mansoor
- Heart and Vascular Institute Division of Cardiology, Department of Medicine and Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Bing Wang
- Molecular Therapy Lab, Stem Cell Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Mousumi Moulik
- Heart, Lung, Blood Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Division of Cardiology, Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Manling Zhang
- Heart, Lung, Blood Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Division of Cardiology, Veteran Affair Pittsburgh Healthcare System, Pittsburgh, PA 15240, USA
- Division of Cardiology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Anita Saraf
- Heart and Vascular Institute Division of Cardiology, Department of Medicine and Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Paola Corti
- Heart, Lung, Blood Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Division of Cardiology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Sruti Shiva
- Heart, Lung, Blood Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Department of Pharmacology & Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
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2
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Hejlesen R, Kjær-Sørensen K, Fago A, Oxvig C. Generation and validation of a myoglobin knockout zebrafish model. Transgenic Res 2023; 32:537-546. [PMID: 37847464 PMCID: PMC10713697 DOI: 10.1007/s11248-023-00369-3] [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: 07/07/2023] [Accepted: 09/20/2023] [Indexed: 10/18/2023]
Abstract
Previous studies using myoglobin (Mb) knockout mice and knockdown zebrafish have presented conflicting results about in vivo phenotypes resulting from the loss of this conserved and highly expressed protein, and therefore a new well-characterized knockout model is warranted. We here describe the generation of three distinct zebrafish mb knockout lines using the CRISPR/Cas system. None of the three lines exhibited any morphological phenotypes, changes in length, or lethality during embryonic and larval development. The adult homozygous knockout mb(Auzf13.2) zebrafish line were absent of Mb protein, had an almost complete degradation of mb mRNA, and showed no changes in viability, length, or heart size. Furthermore, transcriptomic analysis of adult heart tissue showed that mb knockout did not cause altered expression of other genes. Lastly, no off-targeting was observed in 36 screened loci. In conclusion, we have generated three mb knockout lines with indistinguishable phenotypes during embryonic and larval development and validated one of these lines, mb(Auzf13.2), to have no signs of genetic compensation or off-target effects in the adult heart. These findings suggests that the mb(Auzf13.2) shows promise as a candidate for investigating the biological role of Mb in zebrafish.
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Affiliation(s)
- Rasmus Hejlesen
- Department of Biology, Zoophysiology, Aarhus University, Aarhus, Denmark
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Kasper Kjær-Sørensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Angela Fago
- Department of Biology, Zoophysiology, Aarhus University, Aarhus, Denmark.
| | - Claus Oxvig
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
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3
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Alowaysi M, Al-Shehri M, Baadhaim M, AlZahrani H, Aboalola D, Daghestani M, Hashem H, Aljahdali R, Salem R, Alharbi A, Muharraq M, Alghamdi K, Alsobiy F, Zia A, Lehmann R, Tegner J, Alsayegh K. Generation of myoglobin (MB)-knockout human embryonic stem cell (hESC) line (KAIMRCe002-A-1S) using CRISPR/Cas9 technology. Stem Cell Res 2023; 71:103158. [PMID: 37406498 DOI: 10.1016/j.scr.2023.103158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 05/30/2023] [Accepted: 06/24/2023] [Indexed: 07/07/2023] Open
Abstract
Myoglobin (MB) is a cytoplasmic hemoprotein that is predominantly expressed in the heart and oxidative myofibers of skeletal muscle. It has been demonstrated that MB binds to oxygen and promotes its diffusion for energy production in the mitochondria. Recently, MB was found to be expressed in different forms of malignant tumors and cancer cell lines. Further studies using gene disruption technology will enhance the understanding of MB's role in human cardiovascular biology and cancers. Here, we describe the generation of a homozygous MB knockout in human embryonic stem cells (hESC-MB-/-) via CRISPR/Cas9 to study MB function in human biology and diseases.
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Affiliation(s)
- Maryam Alowaysi
- King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Jeddah, Saudi Arabia
| | - Mohammad Al-Shehri
- King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Jeddah, Saudi Arabia
| | - Moayad Baadhaim
- King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Jeddah, Saudi Arabia
| | - Hajar AlZahrani
- King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Jeddah, Saudi Arabia
| | - Doaa Aboalola
- King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Jeddah, Saudi Arabia
| | - Mustafa Daghestani
- King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Jeddah, Saudi Arabia; Department of Pathology and Laboratory Medicine, Ministry of the National Guard - Health Affairs, Jeddah, Saudi Arabia
| | - Heba Hashem
- Department of Pathology and Laboratory Medicine, Ministry of the National Guard - Health Affairs, Jeddah, Saudi Arabia
| | - Rawan Aljahdali
- Department of Pathology and Laboratory Medicine, Ministry of the National Guard - Health Affairs, Jeddah, Saudi Arabia
| | - Rayan Salem
- Department of Pathology and Laboratory Medicine, Ministry of the National Guard - Health Affairs, Jeddah, Saudi Arabia
| | - Adel Alharbi
- Forensic Laboratories, Criminal Evidence Department, Jeddah, Saudi Arabia
| | - Mohammed Muharraq
- Forensic Laboratories, Criminal Evidence Department, Jeddah, Saudi Arabia
| | - Khaled Alghamdi
- Forensic Laboratories, Criminal Evidence Department, Jeddah, Saudi Arabia
| | - Fawaz Alsobiy
- Forensic Laboratories, Criminal Evidence Department, Jeddah, Saudi Arabia
| | - Asima Zia
- Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Robert Lehmann
- Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Jesper Tegner
- Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia; Computer, Electrical and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Khaled Alsayegh
- King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Jeddah, Saudi Arabia.
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4
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Christen L, Broghammer H, Rapöhn I, Möhlis K, Strehlau C, Ribas‐Latre A, Gebhardt C, Roth L, Krause K, Landgraf K, Körner A, Rohde‐Zimmermann K, Hoffmann A, Klöting N, Ghosh A, Sun W, Dong H, Wolfrum C, Rassaf T, Hendgen‐Cotta UB, Stumvoll M, Blüher M, Heiker JT, Weiner J. Myoglobin-mediated lipid shuttling increases adrenergic activation of brown and white adipocyte metabolism and is as a marker of thermogenic adipocytes in humans. Clin Transl Med 2022; 12:e1108. [PMID: 36480426 PMCID: PMC9731393 DOI: 10.1002/ctm2.1108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 10/23/2022] [Accepted: 10/25/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Recruitment and activation of brown adipose tissue (BAT) results in increased energy expenditure (EE) via thermogenesis and represents an intriguing therapeutic approach to combat obesity and treat associated diseases. Thermogenesis requires an increased and efficient supply of energy substrates and oxygen to the BAT. The hemoprotein myoglobin (MB) is primarily expressed in heart and skeletal muscle fibres, where it facilitates oxygen storage and flux to the mitochondria during exercise. In the last years, further contributions of MB have been assigned to the scavenging of reactive oxygen species (ROS), the regulation of cellular nitric oxide (NO) levels and also lipid binding. There is a substantial expression of MB in BAT, which is induced during brown adipocyte differentiation and BAT activation. This suggests MB as a previously unrecognized player in BAT contributing to thermogenesis. METHODS AND RESULTS This study analyzed the consequences of MB expression in BAT on mitochondrial function and thermogenesis in vitro and in vivo. Using MB overexpressing, knockdown or knockout adipocytes, we show that expression levels of MB control brown adipocyte mitochondrial respiratory capacity and acute response to adrenergic stimulation, signalling and lipolysis. Overexpression in white adipocytes also increases their metabolic activity. Mutation of lipid interacting residues in MB abolished these beneficial effects of MB. In vivo, whole-body MB knockout resulted in impaired thermoregulation and cold- as well as drug-induced BAT activation in mice. In humans, MB is differentially expressed in subcutaneous (SC) and visceral (VIS) adipose tissue (AT) depots, differentially regulated by the state of obesity and higher expressed in AT samples that exhibit higher thermogenic potential. CONCLUSIONS These data demonstrate for the first time a functional relevance of MBs lipid binding properties and establish MB as an important regulatory element of thermogenic capacity in brown and likely beige adipocytes.
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Affiliation(s)
- Lisa Christen
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI‐MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital LeipzigLeipzigGermany
| | - Helen Broghammer
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI‐MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital LeipzigLeipzigGermany
| | - Inka Rapöhn
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI‐MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital LeipzigLeipzigGermany
- Medical Department III ‐ EndocrinologyNephrologyRheumatologyUniversity of Leipzig Medical CenterLeipzigGermany
| | - Kevin Möhlis
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI‐MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital LeipzigLeipzigGermany
| | - Christian Strehlau
- Medical Department III ‐ EndocrinologyNephrologyRheumatologyUniversity of Leipzig Medical CenterLeipzigGermany
| | - Aleix Ribas‐Latre
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI‐MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital LeipzigLeipzigGermany
| | - Claudia Gebhardt
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI‐MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital LeipzigLeipzigGermany
| | - Lisa Roth
- Medical Department III ‐ EndocrinologyNephrologyRheumatologyUniversity of Leipzig Medical CenterLeipzigGermany
| | - Kerstin Krause
- Medical Department III ‐ EndocrinologyNephrologyRheumatologyUniversity of Leipzig Medical CenterLeipzigGermany
| | - Kathrin Landgraf
- Center for Pediatric Research Leipzig (CPL)University Hospital for Children and AdolescentsMedical FacultyUniversity of LeipzigLeipzigGermany
| | - Antje Körner
- Center for Pediatric Research Leipzig (CPL)University Hospital for Children and AdolescentsMedical FacultyUniversity of LeipzigLeipzigGermany
| | - Kerstin Rohde‐Zimmermann
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI‐MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital LeipzigLeipzigGermany
| | - Anne Hoffmann
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI‐MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital LeipzigLeipzigGermany
| | - Nora Klöting
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI‐MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital LeipzigLeipzigGermany
| | - Adhideb Ghosh
- Institute of FoodNutrition and HealthETH ZurichSchwerzenbachSwitzerland
| | - Wenfei Sun
- Institute of FoodNutrition and HealthETH ZurichSchwerzenbachSwitzerland
| | - Hua Dong
- Institute of FoodNutrition and HealthETH ZurichSchwerzenbachSwitzerland
| | - Christian Wolfrum
- Institute of FoodNutrition and HealthETH ZurichSchwerzenbachSwitzerland
| | - Tienush Rassaf
- Department of Cardiology and Vascular MedicineWest German Heart and Vascular CenterMedical FacultyUniversity of Duisburg‐EssenEssenGermany
| | - Ulrike B. Hendgen‐Cotta
- Department of Cardiology and Vascular MedicineWest German Heart and Vascular CenterMedical FacultyUniversity of Duisburg‐EssenEssenGermany
| | - Michael Stumvoll
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI‐MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital LeipzigLeipzigGermany
- Medical Department III ‐ EndocrinologyNephrologyRheumatologyUniversity of Leipzig Medical CenterLeipzigGermany
| | - Matthias Blüher
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI‐MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital LeipzigLeipzigGermany
| | - John T. Heiker
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI‐MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital LeipzigLeipzigGermany
- Institute of Biochemistry, Faculty of Life SciencesUniversity of LeipzigLeipzigGermany
| | - Juliane Weiner
- Medical Department III ‐ EndocrinologyNephrologyRheumatologyUniversity of Leipzig Medical CenterLeipzigGermany
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5
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Mori MP, Penjweini R, Knutson JR, Wang PY, Hwang PM. Mitochondria and oxygen homeostasis. FEBS J 2022; 289:6959-6968. [PMID: 34235856 PMCID: PMC8790743 DOI: 10.1111/febs.16115] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/25/2021] [Accepted: 07/07/2021] [Indexed: 01/13/2023]
Abstract
Molecular oxygen possesses a dual nature due to its highly reactive free radical property: it is capable of oxidizing metabolic substrates to generate cellular energy, but can also serve as a substrate for genotoxic reactive oxygen species generation. As a labile substance upon which aerobic life depends, the mechanisms for handling cellular oxygen have been fine-tuned and orchestrated in evolution. Protection from atmospheric oxygen toxicity as originally posited by the Endosymbiotic Theory of the Mitochondrion is likely to be one basic principle underlying oxygen homeostasis. We briefly review the literature on oxygen homeostasis both in vitro and in vivo with a focus on the role of the mitochondrion where the majority of cellular oxygen is consumed. The insights gleaned from these basic mechanisms are likely to be important for understanding disease pathogenesis and developing strategies for maintaining health.
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Affiliation(s)
- Mateus P. Mori
- Cardiovascular Branch; National Heart, Lung, and Blood Institute; National Institutes of Health; Bethesda, Maryland, USA
| | - Rozhin Penjweini
- Laboratory of Advanced Microscopy and Biophotonics; National Heart, Lung, and Blood Institute; National Institutes of Health; Bethesda, Maryland, USA
| | - Jay R. Knutson
- Laboratory of Advanced Microscopy and Biophotonics; National Heart, Lung, and Blood Institute; National Institutes of Health; Bethesda, Maryland, USA
| | - Ping-yuan Wang
- Cardiovascular Branch; National Heart, Lung, and Blood Institute; National Institutes of Health; Bethesda, Maryland, USA
| | - Paul M. Hwang
- Cardiovascular Branch; National Heart, Lung, and Blood Institute; National Institutes of Health; Bethesda, Maryland, USA
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6
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Armbruster J, Aboouf MA, Gassmann M, Egert A, Schorle H, Hornung V, Schmidt T, Schmid-Burgk JL, Kristiansen G, Bicker A, Hankeln T, Zhu H, Gorr TA. Myoglobin regulates fatty acid trafficking and lipid metabolism in mammary epithelial cells. PLoS One 2022; 17:e0275725. [PMID: 36223378 PMCID: PMC9555620 DOI: 10.1371/journal.pone.0275725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/21/2022] [Indexed: 11/18/2022] Open
Abstract
Myoglobin (MB) is known to bind and deliver oxygen in striated muscles at high expression levels. MB is also expressed at much reduced levels in mammary epithelial cells, where the protein´s function is unclear. In this study, we aim to determine whether MB impacts fatty acid trafficking and facilitates aerobic fatty acid ß-oxidation in mammary epithelial cells. We utilized MB-wildtype versus MB-knockout mice and human breast cancer cells to examine the impact of MB and its oxygenation status on fatty acid metabolism in mouse milk and mammary epithelia. MB deficient cells were generated through CRISPR/Cas9 and TALEN approaches and exposed to various oxygen tensions. Fatty acid profiling of milk and cell extracts were performed along with cell labelling and immunocytochemistry. Our findings show that MB expression in mammary epithelial cells promoted fatty acid oxidation while reducing stearyl-CoA desaturase activity for lipogenesis. In cells and milk product, presence of oxygenated MB significantly elevated indices of limited fatty acid ß-oxidation, i.e., the organelle-bound removal of a C2 moiety from long-chain saturated or monounsaturated fatty acids, thus shifting the composition toward more saturated and shorter fatty acid species. Presence of the globin also increased cytoplasmic fatty acid solubility under normoxia and fatty acid deposition to lipid droplets under severe hypoxia. We conclude that MB can function in mammary epithelia as intracellular O2-dependent shuttle of oxidizable fatty acid substrates. MB's impact on limited oxidation of fatty acids could generate inflammatory mediator lipokines, such as 7-hexadecenoate. Thus, the novel functions of MB in breast epithelia described herein range from controlling fatty acid turnover and homeostasis to influencing inflammatory signalling cascade. Future work is needed to analyse to what extent these novel roles of MB also apply to myocytic cell physiology and malignant cell behaviour, respectively.
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Affiliation(s)
- Julia Armbruster
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Mostafa A. Aboouf
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
- Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Angela Egert
- Institute of Pathology, Department of Developmental Pathology, University Hospital Bonn, Bonn, Germany
| | - Hubert Schorle
- Institute of Pathology, Department of Developmental Pathology, University Hospital Bonn, Bonn, Germany
| | - Veit Hornung
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Tobias Schmidt
- Institute of Clinical Chemistry and Clinical Pharmacology, University and University Hospital Bonn, Bonn, Germany
| | - Jonathan L. Schmid-Burgk
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Zurich, Schlieren, Switzerland
| | | | - Anne Bicker
- Institute of Organismic and Molecular Evolution, Molecular and Genome Analysis, Johannes Gutenberg University, Mainz, Germany
| | - Thomas Hankeln
- Institute of Organismic and Molecular Evolution, Molecular and Genome Analysis, Johannes Gutenberg University, Mainz, Germany
| | - Hao Zhu
- Department of Clinical Laboratory Sciences, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Thomas A. Gorr
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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7
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Aboouf MA, Armbruster J, Thiersch M, Gassmann M, Gödecke A, Gnaiger E, Kristiansen G, Bicker A, Hankeln T, Zhu H, Gorr TA. Myoglobin, expressed in brown adipose tissue of mice, regulates the content and activity of mitochondria and lipid droplets. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:159026. [PMID: 34384891 DOI: 10.1016/j.bbalip.2021.159026] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 12/19/2022]
Abstract
The identification of novel physiological regulators that stimulate energy expenditure through brown adipose tissue (BAT) activity in substrate catalysis is of utmost importance to understand and treat metabolic diseases. Myoglobin (MB), known to store or transport oxygen in heart and skeletal muscles, has recently been found to bind fatty acids with physiological constants in its oxygenated form (i.e., MBO2). Here, we investigated the in vivo effect of MB expression on BAT activity. In particular, we studied mitochondrial function and lipid metabolism as essential determinants of energy expenditure in this tissue. We show in a MB-null (MBko) mouse model that MB expression in BAT impacts on the activity of brown adipocytes in a twofold manner: i) by elevating mitochondrial density plus maximal respiration capacity, and through that, by stimulating BAT oxidative metabolism along with the organelles` uncoupled respiration; and ii) by influencing the free fatty acids pool towards a palmitate-enriched composition and shifting the lipid droplet (LD) equilibrium towards higher counts of smaller droplets. These metabolic changes were accompanied by the up-regulated expression of thermogenesis markers UCP1, CIDEA, CIDEC, PGC1-α and PPAR-α in the BAT of MB wildtype (MBwt) mice. Along with the emergence of the "browning" BAT morphology, MBwt mice exhibited a leaner phenotype when compared to MBko littermates at 20 weeks of age. Our data shed novel insights into MB's role in linking oxygen and lipid-based thermogenic metabolism. The findings suggest potential new strategies of targeting the MB pathway to treat metabolic disorders related to diminishing energy expenditure.
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Affiliation(s)
- Mostafa A Aboouf
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland; Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland; Molecular and Translational Biomedicine PhD Program, Life Science Zurich Graduate School, 8057 Zurich, Switzerland; Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, 11566 Cairo, Egypt
| | - Julia Armbruster
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland; Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland; Molecular and Translational Biomedicine PhD Program, Life Science Zurich Graduate School, 8057 Zurich, Switzerland
| | - Markus Thiersch
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland
| | - Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| | - Axel Gödecke
- Institute of Cardiovascular Physiology (A.G.), Medical Faculty, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Erich Gnaiger
- Department of Visceral, Transplant and Thoracic Surgery, D. Swarovski Research Laboratory, Medical University Innsbruck, Innrain 66/6, A-6020 Innsbruck, Austria
| | - Glen Kristiansen
- Institute of Pathology, University Hospital Bonn, University of Bonn, D-53127 Bonn, Germany
| | - Anne Bicker
- Institute of Organismic and Molecular Evolution, Molecular Genetics and Genome Analysis, Johannes Gutenberg University, D-55099 Mainz, Germany
| | - Thomas Hankeln
- Institute of Organismic and Molecular Evolution, Molecular Genetics and Genome Analysis, Johannes Gutenberg University, D-55099 Mainz, Germany
| | - Hao Zhu
- Department of Clinical Laboratory Sciences, The University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA; Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | - Thomas A Gorr
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland.
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8
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Blackburn ML, Wankhade UD, Ono-Moore KD, Chintapalli SV, Fox R, Rutkowsky JM, Willis BJ, Tolentino T, Lloyd KCK, Adams SH. On the potential role of globins in brown adipose tissue: a novel conceptual model and studies in myoglobin knockout mice. Am J Physiol Endocrinol Metab 2021; 321:E47-E62. [PMID: 33969705 PMCID: PMC8321818 DOI: 10.1152/ajpendo.00662.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Myoglobin (Mb) regulates O2 bioavailability in muscle and heart as the partial pressure of O2 (Po2) drops with increased tissue workload. Globin proteins also modulate cellular NO pools, "scavenging" NO at higher Po2 and converting NO2- to NO as Po2 falls. Myoglobin binding of fatty acids may also signal a role in fat metabolism. Interestingly, Mb is expressed in brown adipose tissue (BAT), but its function is unknown. Herein, we present a new conceptual model that proposes links between BAT thermogenic activation, concurrently reduced Po2, and NO pools regulated by deoxy/oxy-globin toggling and xanthine oxidoreductase (XOR). We describe the effect of Mb knockout (Mb-/-) on BAT phenotype [lipid droplets, mitochondrial markers uncoupling protein 1 (UCP1) and cytochrome C oxidase 4 (Cox4), transcriptomics] in male and female mice fed a high-fat diet (HFD, 45% of energy, ∼13 wk), and examine Mb expression during brown adipocyte differentiation. Interscapular BAT weights did not differ by genotype, but there was a higher prevalence of mid-large sized droplets in Mb-/-. COX4 protein expression was significantly reduced in Mb-/- BAT, and a suite of metabolic/NO/stress/hypoxia transcripts were lower. All of these Mb-/--associated differences were most apparent in females. The new conceptual model, and results derived from Mb-/- mice, suggest a role for Mb in BAT metabolic regulation, in part through sexually dimorphic systems and NO signaling. This possibility requires further validation in light of significant mouse-to-mouse variability of BAT Mb mRNA and protein abundances in wild-type mice and lower expression relative to muscle and heart.NEW & NOTEWORTHY Myoglobin confers the distinct red color to muscle and heart, serving as an oxygen-binding protein in oxidative fibers. Less attention has been paid to brown fat, a thermogenic tissue that also expresses myoglobin. In a mouse knockout model lacking myoglobin, brown fat had larger fat droplets and lower markers of mitochondrial oxidative metabolism, especially in females. Gene expression patterns suggest a role for myoglobin as an oxygen/nitric oxide-sensor that regulates cellular metabolic and signaling pathways.
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Affiliation(s)
- Michael L Blackburn
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Umesh D Wankhade
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | | | - Sree V Chintapalli
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Renee Fox
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
| | - Jennifer M Rutkowsky
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, University of California, Davis, California
- Mouse Metabolic Phenotyping Center, University of California, Davis, California
| | - Brandon J Willis
- Mouse Biology Program, University of California, Davis, California
| | - Todd Tolentino
- Mouse Metabolic Phenotyping Center, University of California, Davis, California
- Mouse Biology Program, University of California, Davis, California
| | - K C Kent Lloyd
- Mouse Metabolic Phenotyping Center, University of California, Davis, California
- Mouse Biology Program, University of California, Davis, California
- Department of Surgery, University of California Davis School of Medicine, Sacramento, California
| | - Sean H Adams
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Department of Surgery, University of California Davis School of Medicine, Sacramento, California
- Center for Alimentary and Metabolic Science, University of California Davis School of Medicine, Sacramento, California
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9
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Ono-Moore KD, Olfert IM, Rutkowsky JM, Chintapalli SV, Willis BJ, Blackburn ML, Williams DK, O'Reilly J, Tolentino T, Lloyd KCK, Adams SH. Metabolic physiology and skeletal muscle phenotypes in male and female myoglobin knockout mice. Am J Physiol Endocrinol Metab 2021; 321:E63-E79. [PMID: 33969704 PMCID: PMC8321820 DOI: 10.1152/ajpendo.00624.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Myoglobin (Mb) is a regulator of O2 bioavailability in type I muscle and heart, at least when tissue O2 levels drop. Mb also plays a role in regulating cellular nitric oxide (NO) pools. Robust binding of long-chain fatty acids and long-chain acylcarnitines to Mb, and enhanced glucose metabolism in hearts of Mb knockout (KO) mice, suggest additional roles in muscle intermediary metabolism and fuel selection. To evaluate this hypothesis, we measured energy expenditure (EE), respiratory exchange ratio (RER), body weight gain and adiposity, glucose tolerance, and insulin sensitivity in Mb knockout (Mb-/-) and wild-type (WT) mice challenged with a high-fat diet (HFD, 45% of calories). In males (n = 10/genotype) and females (n = 9/genotype) tested at 5-6, 11-12, and 17-18 wk, there were no genotype effects on RER, EE, or food intake. RER and EE during cold (10°C, 72 h), and glucose and insulin tolerance, were not different compared with within-sex WT controls. At ∼18 and ∼19 wk of age, female Mb-/- adiposity was ∼42%-48% higher versus WT females (P = 0.1). Transcriptomics analyses (whole gastrocnemius, soleus) revealed few consistent changes, with the notable exception of a 20% drop in soleus transferrin receptor (Tfrc) mRNA. Capillarity indices were significantly increased in Mb-/-, specifically in Mb-rich soleus and deep gastrocnemius. The results indicate that Mb loss does not have a major impact on whole body glucose homeostasis, EE, RER, or response to a cold challenge in mice. However, the greater adiposity in female Mb-/- mice indicates a sex-specific effect of Mb KO on fat storage and feed efficiency.NEW & NOTEWORTHY The roles of myoglobin remain to be elaborated. We address sexual dimorphism in terms of outcomes in response to the loss of myoglobin in knockout mice and perform, for the first time, a series of comprehensive metabolic studies under conditions in which fat is mobilized (high-fat diet, cold). The results highlight that myoglobin is not necessary and sufficient for maintaining oxidative metabolism and point to alternative roles for this protein in muscle and heart.
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Affiliation(s)
| | - I Mark Olfert
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Jennifer M Rutkowsky
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, University of California, Davis, California
- Mouse Metabolic Phenotyping Center, University of California, Davis, California
| | - Sree V Chintapalli
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Brandon J Willis
- Mouse Biology Program, University of California, Davis, California
| | - Michael L Blackburn
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - D Keith Williams
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
- Department of Biostatistics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Juliana O'Reilly
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Todd Tolentino
- Mouse Metabolic Phenotyping Center, University of California, Davis, California
- Mouse Biology Program, University of California, Davis, California
| | - K C Kent Lloyd
- Mouse Metabolic Phenotyping Center, University of California, Davis, California
- Mouse Biology Program, University of California, Davis, California
- Department of Surgery, University of California Davis School of Medicine, Sacramento, California
| | - Sean H Adams
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Department of Surgery, University of California Davis School of Medicine, Sacramento, California
- Center for Alimentary and Metabolic Science, University of California Davis School of Medicine, Sacramento, California
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10
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Guensch DP, Michel MC, Huettenmoser SP, Jung B, Gulac P, Segiser A, Longnus SL, Fischer K. The blood oxygen level dependent (BOLD) effect of in-vitro myoglobin and hemoglobin. Sci Rep 2021; 11:11464. [PMID: 34075096 PMCID: PMC8169704 DOI: 10.1038/s41598-021-90908-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 05/18/2021] [Indexed: 01/23/2023] Open
Abstract
The presence of deoxygenated hemoglobin (Hb) results in a drop in T2 and T2* in magnetic resonance imaging (MRI), known as the blood oxygenation level-dependent (BOLD-)effect. The purpose of this study was to investigate if deoxygenated myoglobin (Mb) exerts a BOLD-like effect. Equine Met-Mb powder was dissolved and converted to oxygenated Mb. T1, T2, T2*-maps and BOLD-bSSFP images at 3Tesla were used to scan 22 Mb samples and 12 Hb samples at room air, deoxygenation, reoxygenation and after chemical reduction. In Mb, T2 and T2* mapping showed a significant decrease after deoxygenation (- 25% and - 12%, p < 0.01), increase after subsequent reoxygenation (+ 17% and 0% vs. room air, p < 0.01), and finally a decrease in T2 after chemical reduction (- 28%, p < 0.01). An opposite trend was observed with T1 for each stage, while chemical reduction reduced BOLD-bSSFP signal (- 3%, p < 0.01). Similar deflections were seen at oxygenation changes in Hb. The T1 changes suggests that the oxygen content has been changed in the specimen. The shortening of transverse relaxation times in T2 and T2*-mapping after deoxygenation in Mb specimens are highly indicative of a BOLD-like effect.
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Affiliation(s)
- Dominik P Guensch
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland. .,Department of Diagnostic, Interventional and Paediatric Radiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
| | - Matthias C Michel
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Stefan P Huettenmoser
- Department of Diagnostic, Interventional and Paediatric Radiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Bernd Jung
- Department of Diagnostic, Interventional and Paediatric Radiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Patrik Gulac
- Department of Cardiovascular Surgery, Inselspital, Bern University Hospital, University of Bern , Bern, Switzerland.,Department for BioMedical Research, University of Bern, Bern, Switzerland.,Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University, Bratislava, Slovakia
| | - Adrian Segiser
- Department of Cardiovascular Surgery, Inselspital, Bern University Hospital, University of Bern , Bern, Switzerland.,Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Sarah L Longnus
- Department of Cardiovascular Surgery, Inselspital, Bern University Hospital, University of Bern , Bern, Switzerland.,Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Kady Fischer
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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11
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Yokokawa T, Hashimoto T, Iwanaka N. Caffeine increases myoglobin expression via the cyclic AMP pathway in L6 myotubes. Physiol Rep 2021; 9:e14869. [PMID: 33991466 PMCID: PMC8123560 DOI: 10.14814/phy2.14869] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/07/2020] [Accepted: 12/14/2020] [Indexed: 11/24/2022] Open
Abstract
Myoglobin is an important regulator of muscle and whole‐body metabolism and exercise capacity. Caffeine, an activator of the calcium and cyclic AMP (cAMP)/protein kinase A (PKA) pathway, enhances glucose uptake, fat oxidation, and mitochondrial biogenesis in skeletal muscle cells. However, no study has shown that caffeine increases the endogenous expression of myoglobin in muscle cells. Further, the molecular mechanism underlying the regulation of myoglobin expression remains unclear. Therefore, our aim was to investigate whether caffeine and activators of the calcium signaling and cAMP/PKA pathway increase the expression of myoglobin in L6 myotubes and whether the pathway mediates caffeine‐induced myoglobin expression. Caffeine increased myoglobin expression and activated the cAMP/PKA pathway in L6 muscle cells. Additionally, a cAMP analog significantly increased myoglobin expression, whereas a ryanodine receptor agonist showed no significant effect. Finally, PKA inhibition significantly suppressed caffeine‐induced myoglobin expression in L6 myotubes. These results suggest that caffeine increases myoglobin expression via the cAMP/PKA pathway in skeletal muscle cells.
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Affiliation(s)
- Takumi Yokokawa
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.,Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan.,College of Gastronomy Management, Ritsumeikan University, Shiga, Japan
| | - Takeshi Hashimoto
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Nobumasa Iwanaka
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.,Faculty of Health Science, Kyoto Koka Women's University, Kyoto, Japan
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12
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John NA, O'Brien LT. Insight into type 2 diabetes impaired exercising mitochondrial oxidative flux: is it blood flow, mitochondria, or neither? J Physiol 2021; 600:707-708. [PMID: 33783836 DOI: 10.1113/jp281551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 03/24/2021] [Indexed: 11/08/2022] Open
Affiliation(s)
- Noah A John
- Department of Kinesiology, University of Toronto, Toronto, Ontario, Canada
| | - Liam T O'Brien
- Department of Kinesiology, University of Toronto, Toronto, Ontario, Canada
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13
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Wang PY, Ma J, Li J, Starost MF, Wolfgang MJ, Singh K, Pirooznia M, Kang JG, Hwang PM. Reducing Fatty Acid Oxidation Improves Cancer-free Survival in a Mouse Model of Li-Fraumeni Syndrome. Cancer Prev Res (Phila) 2020; 14:31-40. [PMID: 32958587 DOI: 10.1158/1940-6207.capr-20-0368] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/11/2020] [Accepted: 09/15/2020] [Indexed: 11/16/2022]
Abstract
Germline mutations of TP53, which cause the cancer predisposition disorder Li-Fraumeni syndrome (LFS), can increase mitochondrial activity as well as fatty acid β-oxidation (FAO) in mice. Increased fatty acid metabolism can promote cancer malignancy, but its specific contribution to tumorigenesis in LFS remains unclear. To investigate this, we crossed LFS mice carrying the p53 R172H knock-in mutation (p53172H/H , homolog of the human TP53 R175H LFS mutation) with myoglobin-knockout (MB-/- ) mice known to have decreased FAO. MB-/- p53172H/H double-mutant mice also showed mildly reduced FAO in thymus, a common site of T lymphoma development in LFS mice, in association with an approximately 40% improvement in cancer-free survival time. RNA sequencing profiling revealed that the p53 R172H mutation promotes mitochondrial metabolism and ribosome biogenesis, both of which are suppressed by the disruption of MB. The activation of ribosomal protein S6, involved in protein translation and implicated in cancer promotion, was also inhibited in the absence of MB. To further confirm the role of FAO in lymphomagenesis, mitochondrial FAO enzyme, carnitine palmitoyltransferase 2 (CPT2), was specifically disrupted in T cells of p53172H/H mice using a Cre-loxP-mediated strategy. The heterozygous knockout of CPT2 resulted in thymus FAO haploinsufficiency and an approximately 30% improvement in survival time, paralleling the antiproliferative signaling observed with MB disruption. Thus, this study demonstrates that moderating FAO in LFS can suppress tumorigenesis and improve cancer-free survival with potential implications for cancer prevention. PREVENTION RELEVANCE: Mildly inhibiting the increased fatty acid oxidation observed in a mouse model of Li-Fraumeni syndrome, a cancer predisposition disorder caused by inherited mutations of TP53, dampens aberrant pro-tumorigenic cell signaling and improves the survival time of these mice, thereby revealing a potential strategy for cancer prevention in patients.
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Affiliation(s)
- Ping-Yuan Wang
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland
| | - Jin Ma
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland
| | - Jie Li
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland
| | | | - Michael J Wolfgang
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Komudi Singh
- Bioinformatics and Computational Biology, National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland
| | - Mehdi Pirooznia
- Bioinformatics and Computational Biology, National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland
| | - Ju-Gyeong Kang
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland
| | - Paul M Hwang
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland.
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14
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Lessons from the post-genomic era: Globin diversity beyond oxygen binding and transport. Redox Biol 2020; 37:101687. [PMID: 32863222 PMCID: PMC7475203 DOI: 10.1016/j.redox.2020.101687] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/11/2020] [Accepted: 08/11/2020] [Indexed: 12/16/2022] Open
Abstract
Vertebrate hemoglobin (Hb) and myoglobin (Mb) were among the first proteins whose structures and sequences were determined over 50 years ago. In the subsequent pregenomic period, numerous related proteins came to light in plants, invertebrates and bacteria, that shared the myoglobin fold, a signature sequence motif characteristic of a 3-on-3 α-helical sandwich. Concomitantly, eukaryote and bacterial globins with a truncated 2-on-2 α-helical fold were discovered. Genomic information over the last 20 years has dramatically expanded the list of known globins, demonstrating their existence in a limited number of archaeal genomes, a majority of bacterial genomes and an overwhelming majority of eukaryote genomes. In vertebrates, 6 additional globin types were identified, namely neuroglobin (Ngb), cytoglobin (Cygb), globin E (GbE), globin X (GbX), globin Y (GbY) and androglobin (Adgb). Furthermore, functions beyond the familiar oxygen transport and storage have been discovered within the vertebrate globin family, including NO metabolism, peroxidase activity, scavenging of free radicals, and signaling functions. The extension of the knowledge on globin functions suggests that the original roles of bacterial globins must have been enzymatic, involved in defense against NO toxicity, and perhaps also as sensors of O2, regulating taxis away or towards high O2 concentrations. In this review, we aimed to discuss the evolution and remarkable functional diversity of vertebrate globins with particular focus on the variety of non-canonical expression sites of mammalian globins and their according impressive variability of atypical functions.
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15
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Bicker A, Nauth T, Gerst D, Aboouf MA, Fandrey J, Kristiansen G, Gorr TA, Hankeln T. The role of myoglobin in epithelial cancers: Insights from transcriptomics. Int J Mol Med 2019; 45:385-400. [PMID: 31894249 PMCID: PMC6984796 DOI: 10.3892/ijmm.2019.4433] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/08/2019] [Indexed: 12/25/2022] Open
Abstract
The muscle-associated respiratory protein myoglobin (MB) is expressed in multiple types of cancer, including breast and prostate tumors. In Kaplan-Meier analyses of the two tumor types, MB positivity is associated with favorable prognoses. Despite its well-characterized function in myocytes, the role of MB in cancer remains unclear. To study the impact of endogenous MB expression, small interfering RNA MB-knockdown cells were engineered using breast, prostate and colon cancer cell lines (MDA-MB468, LNCaP, DLD-1), and their transcriptomes were investigated using RNA-Seq at different oxygen levels. In MB-positive cells, increased expression of glycolytic genes was observed, which was possibly mediated by a higher activity of hypoxia-inducible factor 1α. In addition, the results of the gene set enrichment analysis suggested that MB contributed to fatty acid transport and turnover. MB-positive, wild-type-p53 LNCaP cells also exhibited increased expression of p53 target genes involved in cell cycle checkpoint control and prevention of cell migration. MB-positive cells expressing mutant p53 exhibited upregulation of genes associated with prolonged cancer cell viability and motility. Therefore, it was hypothesized that these transcriptomic differences may result from MB-mediated generation of nitric oxide or reactive oxygen species, thus employing established enzymatic activities of the globin. In summary, the transcriptome comparisons identified potential molecular functions of MB in carcinogenesis by highlighting the interaction of MB with key metabolic and regulatory processes.
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Affiliation(s)
- Anne Bicker
- Institute of Organismic and Molecular Evolution, Molecular Genetics and Genome Analysis, Johannes Gutenberg University, D‑55099 Mainz, Germany
| | - Theresa Nauth
- Institute of Organismic and Molecular Evolution, Molecular Genetics and Genome Analysis, Johannes Gutenberg University, D‑55099 Mainz, Germany
| | - Daniela Gerst
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, CH‑8057 Zurich, Switzerland
| | - Mostafa Ahmed Aboouf
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, CH‑8057 Zurich, Switzerland
| | - Joachim Fandrey
- Institute of Physiology, University of Duisburg‑Essen, D‑45147 Essen, Germany
| | - Glen Kristiansen
- Institute of Pathology, Center for Integrated Oncology, University Hospital Bonn, University of Bonn, D‑53127 Bonn, Germany
| | - Thomas Alexander Gorr
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, CH‑8057 Zurich, Switzerland
| | - Thomas Hankeln
- Institute of Organismic and Molecular Evolution, Molecular Genetics and Genome Analysis, Johannes Gutenberg University, D‑55099 Mainz, Germany
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16
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Halama A, Kahal H, Bhagwat AM, Zierer J, Sathyapalan T, Graumann J, Suhre K, Atkin SL. Metabolic and proteomic signatures of hypoglycaemia in type 2 diabetes. Diabetes Obes Metab 2019; 21:909-919. [PMID: 30525282 DOI: 10.1111/dom.13602] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/20/2018] [Accepted: 12/01/2018] [Indexed: 12/31/2022]
Abstract
AIMS To determine the biochemical changes that underlie hypoglycaemia in a healthy control group and in people with type 2 diabetes (T2D). MATERIALS AND METHODS We report a hypoglycaemic clamp study in seven healthy controls and 10 people with T2D. Blood was withdrawn at four time points: at baseline after an overnight fast; after clamping to euglycaemia at 5 mmol/L; after clamping to hypoglycaemia at 2.8 mmol/L; and 24 hours later, after overnight fast. Deep molecular phenotyping using non-targeted metabolomics and the SomaLogic aptamer-based proteomics platform was performed on collected samples. RESULTS A total of 955 metabolites and 1125 proteins were identified, with significant alterations in >90 molecules. A number of metabolites significantly increased during hypoglycaemia, but only cortisol, adenosine-3',5'-cyclic monophosphate (cyclic AMP), and pregnenolone sulphate, were independent of insulin. By contrast, identified protein changes were triggered by hypoglycaemia rather than insulin. The T2D group had significantly higher levels of fatty acids including 10-nonadecenoate, linolenate and dihomo-linoleate during hypoglycaemia compared with the control group. Molecules contributing to cardiovascular complications such as fatty-acid-binding protein-3 and pregnenolone sulphate were altered in the participants with T2D during hypoglycaemia. Almost all molecules returned to baseline at 24 hours. CONCLUSIONS The present study provides a comprehensive description of molecular events that are triggered by insulin-induced hypoglycaemia. We identified deregulated pathways in T2D that may play a role in the pathophysiology of hypoglycaemia-induced cardiovascular complications.
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Affiliation(s)
- Anna Halama
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Doha, Qatar
| | - Hassan Kahal
- Academic Endocrinology, Diabetes and Metabolism, Hull York Medical School, Hull, UK
| | - Aditya M Bhagwat
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Doha, Qatar
| | - Jonas Zierer
- Caryl and Israel Englander Institute for Precision Medicine, Institute for Computational Biomedicine, Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, New York
| | | | - Johannes Graumann
- Proteomics Core, Weill Cornell Medicine-Qatar, Education City, Doha, Qatar
- Scientific Service Group Biomolecular Mass Spectrometry, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Karsten Suhre
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Doha, Qatar
| | - Stephen L Atkin
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Doha, Qatar
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17
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Engelowski E, Modares NF, Gorressen S, Bouvain P, Semmler D, Alter C, Ding Z, Flögel U, Schrader J, Xu H, Lang PA, Fischer J, Floss DM, Scheller J. IL-23R Signaling Plays No Role in Myocardial Infarction. Sci Rep 2018; 8:17078. [PMID: 30459442 PMCID: PMC6244091 DOI: 10.1038/s41598-018-35188-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/08/2018] [Indexed: 01/26/2023] Open
Abstract
Ischemic heart diseases are the most frequent diseases in the western world. Apart from Interleukin (IL-)1, inflammatory therapeutic targets in the clinic are still missing. Interestingly, opposing roles of the pro-inflammatory cytokine IL-23 have been described in cardiac ischemia in mice. IL-23 is a composite cytokine consisting of p19 and p40 which binds to IL-23R and IL-12Rβ1 to initiate signal transduction characterized by activation of the Jak/STAT, PI3K and Ras/Raf/MAPK pathways. Here, we generate IL-23R-Y416FΔICD signaling deficient mice and challenged these mice in close- and open-chest left anterior descending coronary arteria ischemia/reperfusion experiments. Our experiments showed only minimal changes in all assayed parameters in IL-23R signaling deficient mice compared to wild-type mice in ischemia and for up to four weeks of reperfusion, including ejection fraction, endsystolic volume, enddiastolic volume, infarct size, gene regulation and α smooth muscle actin (αSMA) and Hyaluronic acid (HA) protein expression. Moreover, injection of IL-23 in wild-type mice after LAD ischemia/reperfusion had also no influence on the outcome of the healing phase. Our data showed that IL-23R deficiency has no effects in myocardial I/R.
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Affiliation(s)
- Erika Engelowski
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine University, 40225, Düsseldorf, Germany
| | - Nastaran Fazel Modares
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine University, 40225, Düsseldorf, Germany
| | - Simone Gorressen
- Institute of Pharmacology and Clinical Pharmacology, Medical Faculty, Heinrich-Heine University, 40225, Düsseldorf, Germany
| | - Pascal Bouvain
- Institute for Molecular Cardiology, Medical Faculty, Heinrich-Heine University, 40225, Düsseldorf, Germany
| | - Dominik Semmler
- Institute of Pharmacology and Clinical Pharmacology, Medical Faculty, Heinrich-Heine University, 40225, Düsseldorf, Germany
| | - Christina Alter
- Institute for Molecular Cardiology, Medical Faculty, Heinrich-Heine University, 40225, Düsseldorf, Germany
| | - Zhaoping Ding
- Institute for Molecular Cardiology, Medical Faculty, Heinrich-Heine University, 40225, Düsseldorf, Germany
| | - Ulrich Flögel
- Institute for Molecular Cardiology, Medical Faculty, Heinrich-Heine University, 40225, Düsseldorf, Germany
| | - Jürgen Schrader
- Institute for Molecular Cardiology, Medical Faculty, Heinrich-Heine University, 40225, Düsseldorf, Germany
| | - Haifeng Xu
- Institute of Molecular Medicine II, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Philipp A Lang
- Institute of Molecular Medicine II, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Jens Fischer
- Institute of Pharmacology and Clinical Pharmacology, Medical Faculty, Heinrich-Heine University, 40225, Düsseldorf, Germany
| | - Doreen M Floss
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine University, 40225, Düsseldorf, Germany
| | - Jürgen Scheller
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine University, 40225, Düsseldorf, Germany.
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18
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Heinen A, Raupach A, Behmenburg F, Hölscher N, Flögel U, Kelm M, Kaisers W, Nederlof R, Huhn R, Gödecke A. Echocardiographic Analysis of Cardiac Function after Infarction in Mice: Validation of Single-Plane Long-Axis View Measurements and the Bi-Plane Simpson Method. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:1544-1555. [PMID: 29706407 DOI: 10.1016/j.ultrasmedbio.2018.03.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 03/19/2018] [Accepted: 03/22/2018] [Indexed: 06/08/2023]
Abstract
Although echocardiography is commonly used to analyze cardiac function in small animal models of cardiac remodeling after myocardial infarction, the different echocardiographic methods are validated poorly. End-diastolic volume, end-systolic volume and ejection fraction were analyzed using either standard single-plane analysis from parasternal long-axis B-mode views (PSLAX) or the bi-plane Simpson method (using PSLAX and three short-axis views) and validated using magnetic resonance imaging as standard. Ejection fraction measured by PSLAX was moderately correlated with a coefficient of R2 = 0.49. The standard deviation of residuals was 9.91. Simpson analysis revealed an improved correlation coefficient of R2 = 0.77 and a reduction in standard deviation of residuals by 45% (5.45 vs. 9.92, p = 0.014). Subgroup analysis revealed that the high variation in PSLAX is due to changes in ventricular geometry after myocardial infarction. Our results indicate that the bi-plane Simpson method is advantageous for the assessment of cardiac function after myocardial infarction.
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Affiliation(s)
- Andre Heinen
- Institute of Cardiovascular Physiology, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany.
| | - Annika Raupach
- Department of Anesthesiology, University Hospital Düsseldorf, Düsseldorf, Germany
| | | | - Nina Hölscher
- Department of Anesthesiology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Ulrich Flögel
- Department of Molecular Cardiology, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Malte Kelm
- Department of Cardiology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Wolfgang Kaisers
- Department of Anesthesiology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Rianne Nederlof
- Institute of Cardiovascular Physiology, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Ragnar Huhn
- Department of Anesthesiology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Axel Gödecke
- Institute of Cardiovascular Physiology, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
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19
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Rysä J, Tokola H, Ruskoaho H. Mechanical stretch induced transcriptomic profiles in cardiac myocytes. Sci Rep 2018; 8:4733. [PMID: 29549296 PMCID: PMC5856749 DOI: 10.1038/s41598-018-23042-w] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 03/06/2018] [Indexed: 12/15/2022] Open
Abstract
Mechanical forces are able to activate hypertrophic growth of cardiomyocytes in the overloaded myocardium. However, the transcriptional profiles triggered by mechanical stretch in cardiac myocytes are not fully understood. Here, we performed the first genome-wide time series study of gene expression changes in stretched cultured neonatal rat ventricular myocytes (NRVM)s, resulting in 205, 579, 737, 621, and 1542 differentially expressed (>2-fold, P < 0.05) genes in response to 1, 4, 12, 24, and 48 hours of cyclic mechanical stretch. We used Ingenuity Pathway Analysis to predict functional pathways and upstream regulators of differentially expressed genes in order to identify regulatory networks that may lead to mechanical stretch induced hypertrophic growth of cardiomyocytes. We also performed micro (miRNA) expression profiling of stretched NRVMs, and identified that a total of 8 and 87 miRNAs were significantly (P < 0.05) altered by 1-12 and 24-48 hours of mechanical stretch, respectively. Finally, through integration of miRNA and mRNA data, we predicted the miRNAs that regulate mRNAs potentially leading to the hypertrophic growth induced by mechanical stretch. These analyses predicted nuclear factor-like 2 (Nrf2) and interferon regulatory transcription factors as well as the let-7 family of miRNAs as playing roles in the regulation of stretch-regulated genes in cardiomyocytes.
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Affiliation(s)
- Jaana Rysä
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland.
- Research Unit of Biomedicine, Pharmacology and Toxicology, University of Oulu, Oulu, Finland.
| | - Heikki Tokola
- Research Unit of Biomedicine, Pharmacology and Toxicology, University of Oulu, Oulu, Finland
- Department of Pathology, Cancer Research and Translational Medicine Research Unit, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Heikki Ruskoaho
- Research Unit of Biomedicine, Pharmacology and Toxicology, University of Oulu, Oulu, Finland
- Drug Research Program, Division of Pharmacology and Pharmacotherapy, University of Helsinki, Helsinki, Finland
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20
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Jue T, Shih L, Chung Y. Differential Interaction of Myoglobin with Select Fatty Acids of Carbon Chain Lengths C8 to C16. Lipids 2017. [PMID: 28639182 DOI: 10.1007/s11745-017-4272-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Previous studies have shown that palmitic acid (PAM) and oleic acid (OLE) can bind myoglobin (Mb). How fatty acids (FA) with different carbon chain lengths and sulfate substitution interact with Mb remains uncertain. Indeed, C8:0 and C10:0 fatty acids do not perturb the intensities of the 1H-NMR MbCN signal intensity at FA:Mb ratios below 2:1. Starting with C12:0, C12:0-C16:0, FA induce a noticeable spectral change. C12:0 and C14:0 FA affect both the 5- and 8-heme methyl signals, whereas the C16:0 FA perturbs only the 8-heme methyl signal. All C12:0-C16:0 saturated FA induce upfield shifts in the -CH2 peak of different FA in the presence of Mb. Increasing the apparent solubility with a sulfate group substitution enhances the FA interaction of lauric sulfate (LAU 1-SO4) but not palmitate sulfate acid (PAM 1-SO4). The detergent (DET) property of FA has no significant contribution. Common positive, neutral, and negative DET at DET:Mb ratio of 1:1 induce no perturbation of the MbCN spectra. The experiment observations establish a basis to investigate the molecular mechanism underlying the FA interaction with Mb.
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Affiliation(s)
- Thomas Jue
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA.
| | - Lifan Shih
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA
| | - Youngran Chung
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA
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21
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Jue T, Simond G, Wright TJ, Shih L, Chung Y, Sriram R, Kreutzer U, Davis RW. Effect of fatty acid interaction on myoglobin oxygen affinity and triglyceride metabolism. J Physiol Biochem 2017; 73:359-370. [PMID: 28357578 DOI: 10.1007/s13105-017-0559-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 03/08/2017] [Indexed: 01/04/2023]
Abstract
Recent studies have suggested myoglobin (Mb) may have other cellular functions in addition to storing and transporting O2. Indeed, NMR experiments have shown that the saturated fatty acid (FA) palmitate (PA) can interact with myoglobin (Mb) in its ligated state (MbCO and MbCN) but does not interact with Mb in its deoxygenated state. The observation has led to the hypothesis that Mb can also serve as a fatty acid transporter. The present study further investigates fatty acid interaction with the physiological states of Mb using the more soluble but unsaturated fatty acid, oleic acid (OA). OA binds to MbCO but does not bind to deoxy Mb. OA binding to Mb, however, does not alter its O2 affinity. Without any Mb, muscle has a significantly lower level of triglyceride (TG). In Mb knock-out (MbKO) mice, both heart and skeletal muscles have lower level of TG relative to the control mice. Training further decreases the relative TG in the MbKO skeletal muscle. Nevertheless, the absence of Mb and lower TG level in muscle does not impair the MbKO mouse performance as evidenced by voluntary wheel running measurements. The results support the hypothesis of a complex physiological role for Mb, especially with respect to fatty acid metabolism.
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Affiliation(s)
- Thomas Jue
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA.
| | - Gregory Simond
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA
| | - Traver J Wright
- Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Lifan Shih
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA
| | - Youngran Chung
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA
| | - Renuka Sriram
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA
| | - Ulrike Kreutzer
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA
| | - Randall W Davis
- Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX, 77843, USA
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22
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Hendgen-Cotta UB, Esfeld S, Coman C, Ahrends R, Klein-Hitpass L, Flögel U, Rassaf T, Totzeck M. A novel physiological role for cardiac myoglobin in lipid metabolism. Sci Rep 2017; 7:43219. [PMID: 28230173 PMCID: PMC5322402 DOI: 10.1038/srep43219] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 01/20/2017] [Indexed: 02/06/2023] Open
Abstract
Continuous contractile activity of the heart is essential and the required energy is mostly provided by fatty acid (FA) oxidation. Myocardial lipid accumulation can lead to pathological responses, however the underlying mechanisms remain elusive. The role of myoglobin in dioxygen binding in cardiomyocytes and oxidative skeletal muscle has widely been appreciated. Our recent work established myoglobin as a protector of cardiac function in hypoxia and disease states. We here unravel a novel role of cardiac myoglobin in governing FA metabolism to ensure the physiological energy production through β-oxidation, preventing myocardial lipid accumulation and preserving cardiac functions. In vivo1H magnetic resonance spectroscopy unveils a 3-fold higher deposition of lipids in mouse hearts lacking myoglobin, which was associated with depressed cardiac function compared to wild-type hearts as assessed by echocardiography. Mass spectrometry reveals a marked increase in tissue triglycerides with preferential incorporation of palmitic and oleic acids. Phospholipid levels as well as the metabolome, transcriptome and proteome related to FA metabolism tend to be unaffected by myoglobin ablation. Our results reveal a physiological role of myoglobin in FA metabolism with the lipid accumulation-suppressing effects of myoglobin preventing cardiac lipotoxicity.
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Affiliation(s)
- Ulrike B Hendgen-Cotta
- University Hospital Essen, Medical Faculty, West German Heart and Vascular Center, Department of Cardiology and Department of Angiology, Hufelandstr. 55, 45147 Essen, Germany
| | - Sonja Esfeld
- University Hospital Essen, Medical Faculty, West German Heart and Vascular Center, Department of Cardiology and Department of Angiology, Hufelandstr. 55, 45147 Essen, Germany
| | - Cristina Coman
- Leibniz-Institut für Analytische Wissenschaften-ISAS e.V. Otto-Hahn-Str. 6b, 44227 Dortmund, Germany
| | - Robert Ahrends
- Leibniz-Institut für Analytische Wissenschaften-ISAS e.V. Otto-Hahn-Str. 6b, 44227 Dortmund, Germany
| | - Ludger Klein-Hitpass
- University Hospital Essen, Institute of Cell Biology, Medical Faculty, Virchowstr. 173, 45122 Essen, Germany
| | - Ulrich Flögel
- University Hospital Düsseldorf, Department of Molecular Cardiology, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Tienush Rassaf
- University Hospital Essen, Medical Faculty, West German Heart and Vascular Center, Department of Cardiology and Department of Angiology, Hufelandstr. 55, 45147 Essen, Germany
| | - Matthias Totzeck
- University Hospital Essen, Medical Faculty, West German Heart and Vascular Center, Department of Cardiology and Department of Angiology, Hufelandstr. 55, 45147 Essen, Germany
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23
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Peters EL, Offringa C, Kos D, Van der Laarse WJ, Jaspers RT. Regulation of myoglobin in hypertrophied rat cardiomyocytes in experimental pulmonary hypertension. Pflugers Arch 2016; 468:1697-707. [PMID: 27572699 PMCID: PMC5026723 DOI: 10.1007/s00424-016-1865-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 07/21/2016] [Accepted: 08/04/2016] [Indexed: 01/29/2023]
Abstract
A major problem in chronic heart failure is the inability of hypertrophied cardiomyocytes to maintain the required power output. A Hill-type oxygen diffusion model predicts that oxygen supply is limiting in hypertrophied cardiomyocytes at maximal rates of oxygen consumption and that this limitation can be reduced by increasing the myoglobin (Mb) concentration. We explored how cardiac hypertrophy, oxidative capacity, and Mb expression in right ventricular cardiomyocytes are regulated at the transcriptional and translational levels in an early stage of experimental pulmonary hypertension, in order to identify targets to improve the oxygen supply/demand ratio. Male Wistar rats were injected with monocrotaline to induce pulmonary hypertension (PH) and right ventricular heart failure. The messenger RNA (mRNA) expression levels per nucleus of growth factors insulin-like growth factor-1Ea (IGF-1Ea) and mechano growth factor (MGF) were higher in PH than in healthy controls, consistent with a doubling in cardiomyocyte cross-sectional area (CSA). Succinate dehydrogenase (SDH) activity was unaltered, indicating that oxidative capacity per cell increased. Although the Mb protein concentration was unchanged, Mb mRNA concentration was reduced. However, total RNA per nucleus was about threefold higher in PH rats versus controls, and Mb mRNA content expressed per nucleus was similar in the two groups. The increase in oxidative capacity without an increase in oxygen supply via Mb-facilitated diffusion caused a doubling of the critical extracellular oxygen tension required to prevent hypoxia (PO2crit). We conclude that Mb mRNA expression is not increased during pressure overload-induced right ventricular hypertrophy and that the increase in myoglobin content per myocyte is likely due to increased translation. We conclude that increasing Mb mRNA expression may be beneficial in the treatment of experimental PH.
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Affiliation(s)
- E L Peters
- Laboratory for Myology, Faculty of Behavioral and Movement Sciences, Department of Human Movement Sciences, MOVE Research Institute Amsterdam, Vrije Universiteit Amsterdam, van der Boechorststraat 7, 1081, BT, Amsterdam, The Netherlands
| | - C Offringa
- Laboratory for Myology, Faculty of Behavioral and Movement Sciences, Department of Human Movement Sciences, MOVE Research Institute Amsterdam, Vrije Universiteit Amsterdam, van der Boechorststraat 7, 1081, BT, Amsterdam, The Netherlands
| | - D Kos
- Laboratory for Myology, Faculty of Behavioral and Movement Sciences, Department of Human Movement Sciences, MOVE Research Institute Amsterdam, Vrije Universiteit Amsterdam, van der Boechorststraat 7, 1081, BT, Amsterdam, The Netherlands.,Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - W J Van der Laarse
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - R T Jaspers
- Laboratory for Myology, Faculty of Behavioral and Movement Sciences, Department of Human Movement Sciences, MOVE Research Institute Amsterdam, Vrije Universiteit Amsterdam, van der Boechorststraat 7, 1081, BT, Amsterdam, The Netherlands.
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24
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Abstract
Previous studies have shown that palmitate (PA) can interact with myoglobin (Mb). The present study has investigated the interaction of the more soluble unsaturated fatty acid, oleic acid (OA). Indeed, (1)H NMR measurements of the Mb signal during OA titration also show signal changes consistent with specific and non-specific binding. At OA:Mb ratio<4:1, OA perturbs selectively the 8-heme methyl signal, consistent with a local and specific fatty acid-protein interaction. As OA:Mb ratio increases from 4:1 to 40:1, all hyperfine shifted MbCN signals decrease, consistent with a non-selective, global perturbation of the protein. The pH titration analysis indicates that the observed OA methylene signal in the presence of Mb reflects a non-specific interaction and does not originate from a shift in the lamella-micelle equilibrium. Given the OA interaction with Mb, a fatty acid flux model suggests that Mb can play a fatty acid transport role under certain physiological conditions.
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Affiliation(s)
- Lifan Shih
- Biochemistry and Molecular Medicine, University of California, Davis, Davis CA 95616-8635, United States
| | - Youngran Chung
- Biochemistry and Molecular Medicine, University of California, Davis, Davis CA 95616-8635, United States
| | - Renuka Sriram
- Biochemistry and Molecular Medicine, University of California, Davis, Davis CA 95616-8635, United States
| | - Thomas Jue
- Biochemistry and Molecular Medicine, University of California, Davis, Davis CA 95616-8635, United States.
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25
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Souza KDP, Nunes MT. Neonatal hyper- and hypothyroidism alter the myoglobin gene expression program in adulthood. ACTA ACUST UNITED AC 2015; 47:670-8. [PMID: 25098716 PMCID: PMC4165294 DOI: 10.1590/1414-431x20142875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Indexed: 05/28/2023]
Abstract
Myoglobin acts as an oxygen store and a reactive oxygen species acceptor in muscles.
We examined myoglobin mRNA in rat cardiac ventricle and skeletal muscles during the
first 42 days of life and the impact of transient neonatal hypo- and hyperthyroidism
on the myoglobin gene expression pattern. Cardiac ventricle and skeletal muscles of
Wistar rats at 7-42 days of life were quickly removed, and myoglobin mRNA was
determined by Northern blot analysis. Rats were treated with propylthiouracil (5-10
mg/100 g) and triiodothyronine (0.5-50 µg/100 g) for 5, 15, or 30 days after birth to
induce hypo- and hyperthyroidism and euthanized either just after treatment or at 90
days. During postnatal (P) days 7-28, the ventricle myoglobin mRNA remained
unchanged, but it gradually increased in skeletal muscle (12-fold). Triiodothyronine
treatment, from days P0-P5, increased the skeletal muscle myoglobin mRNA 1.5- to
4.5-fold; a 2.5-fold increase was observed in ventricle muscle, but only when
triiodothyronine treatment was extended to day P15. Conversely, hypothyroidism at P5
markedly decreased (60%) ventricular myoglobin mRNA. Moreover, transient
hyperthyroidism in the neonatal period increased ventricle myoglobin mRNA (2-fold),
and decreased heart rate (5%), fast muscle myoglobin mRNA (30%) and body weight (20%)
in adulthood. Transient hypothyroidism in the neonatal period also permanently
decreased fast muscle myoglobin mRNA (30%) and body weight (14%). These results
indicated that changes in triiodothyronine supply in the neonatal period alter the
myoglobin expression program in ventricle and skeletal muscle, leading to specific
physiological repercussions and alterations in other parameters in adulthood.
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Affiliation(s)
- K de Picoli Souza
- Faculdade de Ciências Biológicas e Ambientais, Universidade Federal da Grande Dourados, Dourados, MS, Brasil
| | - M T Nunes
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
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26
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Chintapalli SV, Bhardwaj G, Patel R, Shah N, Patterson RL, van Rossum DB, Anishkin A, Adams SH. Molecular dynamic simulations reveal the structural determinants of Fatty Acid binding to oxy-myoglobin. PLoS One 2015; 10:e0128496. [PMID: 26030763 PMCID: PMC4451517 DOI: 10.1371/journal.pone.0128496] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 04/27/2015] [Indexed: 11/18/2022] Open
Abstract
The mechanism(s) by which fatty acids are sequestered and transported in muscle have not been fully elucidated. A potential key player in this process is the protein myoglobin (Mb). Indeed, there is a catalogue of empirical evidence supporting direct interaction of globins with fatty acid metabolites; however, the binding pocket and regulation of the interaction remains to be established. In this study, we employed a computational strategy to elucidate the structural determinants of fatty acids (palmitic & oleic acid) binding to Mb. Sequence analysis and docking simulations with a horse (Equus caballus) structural Mb reference reveals a fatty acid-binding site in the hydrophobic cleft near the heme region in Mb. Both palmitic acid and oleic acid attain a "U" shaped structure similar to their conformation in pockets of other fatty acid-binding proteins. Specifically, we found that the carboxyl head group of palmitic acid coordinates with the amino group of Lys45, whereas the carboxyl group of oleic acid coordinates with both the amino groups of Lys45 and Lys63. The alkyl tails of both fatty acids are supported by surrounding hydrophobic residues Leu29, Leu32, Phe33, Phe43, Phe46, Val67, Val68 and Ile107. In the saturated palmitic acid, the hydrophobic tail moves freely and occasionally penetrates deeper inside the hydrophobic cleft, making additional contacts with Val28, Leu69, Leu72 and Ile111. Our simulations reveal a dynamic and stable binding pocket in which the oxygen molecule and heme group in Mb are required for additional hydrophobic interactions. Taken together, these findings support a mechanism in which Mb acts as a muscle transporter for fatty acid when it is in the oxygenated state and releases fatty acid when Mb converts to deoxygenated state.
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Affiliation(s)
- Sree V. Chintapalli
- Arkansas Children’s Nutrition Center, and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
- * E-mail: (SVC); (SHA)
| | - Gaurav Bhardwaj
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Reema Patel
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Natasha Shah
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Randen L. Patterson
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Damian B. van Rossum
- Center for Computational Proteomics, The Pennsylvania State University, State College, Pennsylvania, United States of America
- Department of Biology, The Pennsylvania State University, State College, Pennsylvania, United States of America
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, Maryland, United States of America
| | - Sean H. Adams
- Arkansas Children’s Nutrition Center, and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
- * E-mail: (SVC); (SHA)
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27
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Meller S, Bicker A, Montani M, Ikenberg K, Rostamzadeh B, Sailer V, Wild P, Dietrich D, Uhl B, Sulser T, Moch H, Gorr TA, Stephan C, Jung K, Hankeln T, Kristiansen G. Myoglobin expression in prostate cancer is correlated to androgen receptor expression and markers of tumor hypoxia. Virchows Arch 2014; 465:419-27. [PMID: 25172328 DOI: 10.1007/s00428-014-1646-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 07/30/2014] [Accepted: 08/18/2014] [Indexed: 11/29/2022]
Abstract
Recent studies identified unexpected expression and transcriptional complexity of the hemoprotein myoglobin (MB) in human breast cancer but its role in prostate cancer is still unclear. Expression of MB was immunohistochemically analyzed in three independent cohorts of radical prostatectomy specimens (n = 409, n = 625, and n = 237). MB expression data were correlated with clinicopathological parameters and molecular parameters of androgen and hypoxia signaling. Expression levels of novel tumor-associated MB transcript variants and the VEGF gene as a hypoxia marker were analyzed using qRT-PCR. Fifty-three percent of the prostate cancer cases were MB positive and significantly correlated with androgen receptor (AR) expression (p < 0.001). The positive correlation with CAIX (p < 0.001) and FASN (p = 0.008) as well as the paralleled increased expression of the tumor-associated MB transcript variants and VEGF suggest that hypoxia participates in MB expression regulation. Analogous to breast cancer, MB expression in prostate cancer is associated with steroid hormone signaling and markers of hypoxia. Further studies must elucidate the novel functional roles of MB in human carcinomas, which probably extend beyond its classic intramuscular function in oxygen storage.
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Affiliation(s)
- Sebastian Meller
- Institute of Pathology, University Hospital Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany
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28
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Shih L, Chung Y, Sriram R, Jue T. Palmitate interaction with physiological states of myoglobin. Biochim Biophys Acta Gen Subj 2014; 1840:656-66. [PMID: 24482816 DOI: 10.1016/j.bbagen.2013.10.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Previous studies have shown that palmitate (PA) can bind specifically and non-specifically to Fe(III)MbCN. The present study has observed PA interaction with physiological states of Fe(II)Mb, and the observations support the hypothesis that Mb may have a potential role in facilitating intracellular fatty acid transport. METHODS 1H NMR spectra measurements of the Mb signal during PA titration show signal changes consistent with specific and non-specific binding. RESULTS Palmitate (PA) interacts differently with physiological states of Mb. Deoxy Mb does not interact specifically or non-specifically with PA, while the carbonmonoxy myoglobin (MbCO) interaction with PA decreases the intensity of selective signals and produces a 0.15ppmupfield shift of the PAmethylene peak. The selective signal change upon PA titration provides a basis to determine an apparent PA binding constant,which serves to create a model comparing the competitive PA binding and facilitated fatty acid transport of Mb and fatty acid binding protein(FABP). CONCLUSIONS Given contrasting PA interaction of ligated vs. unligated Mb, the cellular fatty acid binding protein(FABP) and Mb concentration in the cell, the reported cellular diffusion coefficients, the PA dissociation constants from ligated Mb and FABP, a fatty acid flux model suggests that Mb can compete with FABP transporting cellular fatty acid. GENERAL SIGNIFICANCE Under oxygenated conditions and continuous energy demand, Mb dependent fatty acid transport could influence the cell's preference for carbohydrate or fatty acid as a fuel source and regulate fatty acid metabolism.
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29
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Molecular cloning, characterization and expression of myoglobin in Tibetan antelope (Pantholops hodgsonii), a species with hypoxic tolerance. Gene 2014; 533:532-7. [DOI: 10.1016/j.gene.2013.09.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 08/17/2013] [Accepted: 09/08/2013] [Indexed: 11/17/2022]
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30
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Rubio I, Suva LJ, Todorova V, Bhattacharyya S, Kaufmann Y, Maners A, Smith M, Klimberg VS. Oral Glutamine Reduces Radiation Morbidity in Breast Conservation Surgery. JPEN J Parenter Enteral Nutr 2013; 37:623-30. [DOI: 10.1177/0148607112474994] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
| | - Larry J. Suva
- Department of Orthopedic Surgery, Center for Orthopedic Research, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | | | - Sudeepa Bhattacharyya
- Department of Orthopedic Surgery, Center for Orthopedic Research, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas
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31
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Aerobic dive limits of seals with mutant myoglobin using combined thermochemical and physiological data. Comp Biochem Physiol A Mol Integr Physiol 2013; 164:119-28. [DOI: 10.1016/j.cbpa.2012.10.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Revised: 10/12/2012] [Accepted: 10/14/2012] [Indexed: 11/19/2022]
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Borst O, Ochmann C, Schönberger T, Jacoby C, Stellos K, Seizer P, Flögel U, Lang F, Gawaz M. Methods employed for induction and analysis of experimental myocardial infarction in mice. Cell Physiol Biochem 2011; 28:1-12. [PMID: 21865843 DOI: 10.1159/000331708] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2011] [Indexed: 11/19/2022] Open
Abstract
Myocardial ischemia und subsequent reperfusion is followed by a complex sequence of pathophysiological responses involving inflammatory cell infiltration and cytokine release as well as postinfarction wound healing and myocardial tissue remodeling. With the development of gene targeted mice the contribution of individual gene products to the pathophysiology of myocardial ischemia and reperfusion can be defined leading to an increasing interest in the widely-used mouse model of myocardial infarction. This methological paper describes in detail the required equipment, surgical instruments, drugs and additional material, the methods of anesthesia and analgesia, the procedures involved in preparation of the animal, tracheotomy, intubation, thoracotomy, occlusion of the left descending artery, removal of the heart, determination of infarct size, analysis of cardiac functional parameters with echocardiography and magnetic resonance imaging (MRI) as well as determination of the morphological consequences utilizing gelatin zymography, histology and immunohistochemistry.
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Affiliation(s)
- Oliver Borst
- Department of Cardiology and Cardiovascular Medicine, University Hospital Tübingen, Tübingen, Germany
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Gorr TA, Wichmann D, Pilarsky C, Theurillat JP, Fabrizius A, Laufs T, Bauer T, Koslowski M, Horn S, Burmester T, Hankeln T, Kristiansen G. Old proteins - new locations: myoglobin, haemoglobin, neuroglobin and cytoglobin in solid tumours and cancer cells. Acta Physiol (Oxf) 2011; 202:563-81. [PMID: 20958924 DOI: 10.1111/j.1748-1716.2010.02205.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM The unexpected identification of myoglobin (MB) in breast cancer prompted us to evaluate the clinico-pathological value of MB, haemoglobin (HB) and cytoglobin (CYGB) in human breast carcinoma cases. We further screened for the presence of neuroglobin (NGB) and CYGB in tumours of diverse origin, and assessed the O(2) -response of HB, MB and CYGB mRNAs in cancer cell lines, to better elicit the links between this ectopic globin expression and tumour hypoxia. METHODS Breast tumours were analysed by immunohistochemistry for HB, MB and CYGB and correlated with clinico-pathological parameters. Screening for CYGB and NGB mRNA expression in tumour entities was performed by hybridization, quantitative PCR (qPCR) and bioinformatics. Hypoxic or anoxic responses of HB, MB and CYGB mRNAs was analysed by qPCR in human Hep3B, MCF7, HeLa and RCC4 cancer cell lines. RESULTS 78.8% of breast cancer cases were positive for MB, 77.9% were positive for HB and 55.4% expressed CYGB. The closest correlation with markers of hypoxia was observed for CYGB. Compared to the weakly positive status of MB in healthy breast tissues, invasive tumours either lost or up-regulated MB. Breast carcinomas showed the tendency to silence CYGB. HB was not seen in normal tissues and up-regulated in tumours. Beyond breast malignancies, expression levels of NGB and CYGB mRNAs were extremely low in brain tumours (glioblastoma, astrocytoma). NGB was not observed in non-brain tumours. CYGB mRNA, readily detectable in breast cancer and other tumours, is down-regulated in lung adenocarcinomas. Alpha1 globin (α1 globin) and Mb were co-expressed in MCF7 and HeLa cells; CYGB transcription was anoxia-inducible in Hep3B and RCC4 cells. CONCLUSIONS This is the first time that HB and CYGB are reported in breast cancer. Neither NGB nor CYGB are systematically up-regulated in tumours. The down-regulated CYGB expression in breast and lung tumours is in line with a tumour-suppressor role. Each of the screened cancer cells expresses at least one globin (i.e. main globin species: CYGB in Hep3B; α1 globin + MB in MCF7 and HeLa). Thus, globins exist in a wide variety of solid tumours. However, the generally weak expression of the endogenous proteins in the cancer argues against a significant contribution to tumour oxygenation. Future studies should consider that cancer-expressed globins might function in ways not directly linked to the binding and transport of oxygen.
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Affiliation(s)
- T A Gorr
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland.
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Abstract
Myoglobin is a well-characterized, cytoplasmic hemoprotein that is expressed primarily in cardiomyocytes and oxidative skeletal muscle fibers. However, recent studies also suggest low-level myoglobin expression in various non-muscle tissues. Prior studies incorporating molecular, pharmacological, physiological and transgenic technologies have demonstrated that myoglobin is an essential oxygen-storage hemoprotein capable of facilitating oxygen transport and modulating nitric oxide homeostasis within cardiac and skeletal myocytes. Concomitant with these studies, scientific investigations into the transcriptional regulation of myoglobin expression have been undertaken. These studies have indicated that activation of key transcription factors (MEF2, NFAT and Sp1) and co-activators (PGC-1alpha) by locomotor activity, differential intracellular calcium fluxes and low intracellular oxygen tension collectively regulate myoglobin expression. Future studies focused on tissue-specific transcriptional regulatory pathways and post-translational modifications governing myoglobin expression will need to be undertaken. Finally, further studies investigating the modulation of myoglobin expression under various myopathic processes may identify myoglobin as a novel therapeutic target for the treatment of various cardiac and skeletal myopathies.
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Affiliation(s)
- Shane B Kanatous
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
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Mersmann J, Habeck K, Latsch K, Zimmermann R, Jacoby C, Fischer JW, Hartmann C, Schrader J, Kirschning CJ, Zacharowski K. Left ventricular dilation in toll-like receptor 2 deficient mice after myocardial ischemia/reperfusion through defective scar formation. Basic Res Cardiol 2010; 106:89-98. [PMID: 20967453 DOI: 10.1007/s00395-010-0127-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 09/23/2010] [Accepted: 10/06/2010] [Indexed: 12/15/2022]
Abstract
Restoration of myocardial blood flow after ischemia triggers an inflammatory response involving toll-like receptors (TLRs). TLR2(-/-)-mice show short-term advantages upon reperfusion injury as compared with WT controls. Accordingly, it has been shown that transient TLR2-blockade prior to reperfusion is associated with improved left-ventricular performance after myocardial scar formation. We present here adverse myocardial remodeling due to a chronic lack of TLR2 expression. Myocardial ischemia/reperfusion (MI/R) was surgically induced in C3HeN-mice by ligation of the left anterior descending coronary artery for 20 min, followed by 24 h or 28 days of reperfusion. TLR2(-/-)-mice and TLR2-Ab treated (T2.5) WT-mice displayed a reduction of infarct size, plasma troponin T concentrations, and leukocyte infiltration as compared with untreated controls after 24 h of reperfusion. After 28 days, however, magnetic resonance imaging revealed a marked left ventricular dilation in TLR2(-/-)-animals, which was associated with pronounced matrix remodeling characterized by reduced collagen and decorin density in the infarct scar. Our data show adverse effects on myocardial remodeling in TLR2(-/-)-mice. Although interception with TLR2 signaling is a promising concept for the prevention of reperfusion injury after myocardial ischemia, these data give cause for serious concern with respect to the time-point and duration of the potential treatment.
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Affiliation(s)
- Jan Mersmann
- Clinic of Anaesthesiology, Intensive Care Medicine, and Pain Therapy, University Hospital Frankfurt, 60590 Frankfurt am Main, Germany
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Ojaimi C, Kinugawa S, Recchia FA, Hintze TH. Oxidant-NO dependent gene regulation in dogs with type I diabetes: impact on cardiac function and metabolism. Cardiovasc Diabetol 2010; 9:43. [PMID: 20735837 PMCID: PMC2936363 DOI: 10.1186/1475-2840-9-43] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 08/24/2010] [Indexed: 11/17/2022] Open
Abstract
Background The mechanisms responsible for the cardiovascular mortality in type I diabetes (DM) have not been defined completely. We have shown in conscious dogs with DM that: 1) baseline coronary blood flow (CBF) was significantly decreased, 2) endothelium-dependent (ACh) coronary vasodilation was impaired, and 3) reflex cholinergic NO-dependent coronary vasodilation was selectively depressed. The most likely mechanism responsible for the depressed reflex cholinergic NO-dependent coronary vasodilation was the decreased bioactivity of NO from the vascular endothelium. The goal of this study was to investigate changes in cardiac gene expression in a canine model of alloxan-induced type 1 diabetes. Methods Mongrel dogs were chronically instrumented and the dogs were divided into two groups: one normal and the other diabetic. In the diabetic group, the dogs were injected with alloxan monohydrate (40-60 mg/kg iv) over 1 min. The global changes in cardiac gene expression in dogs with alloxan-induced diabetes were studied using Affymetrix Canine Array. Cardiac RNA was extracted from the control and DM (n = 4). Results The array data revealed that 797 genes were differentially expressed (P < 0.01; fold change of at least ±2). 150 genes were expressed at significantly greater levels in diabetic dogs and 647 were significantly reduced. There was no change in eNOS mRNA. There was up regulation of some components of the NADPH oxidase subunits (gp91 by 2.2 fold, P < 0.03), and down-regulation of SOD1 (3 fold, P < 0.001) and decrease (4 - 40 fold) in a large number of genes encoding mitochondrial enzymes. In addition, there was down-regulation of Ca2+ cycling genes (ryanodine receptor; SERCA2 Calcium ATPase), structural proteins (actin alpha). Of particular interests are genes involved in glutathione metabolism (glutathione peroxidase 1, glutathione reductase and glutathione S-transferase), which were markedly down regulated. Conclusion our findings suggest that type I diabetes might have a direct effect on the heart by impairing NO bioavailability through oxidative stress and perhaps lipid peroxidases.
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Affiliation(s)
- Caroline Ojaimi
- Department of Physiology, New York Medical College, Valhalla, NY 10595, USA.
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Gros G, Wittenberg BA, Jue T. Myoglobin's old and new clothes: from molecular structure to function in living cells. J Exp Biol 2010; 213:2713-25. [PMID: 20675540 PMCID: PMC2912754 DOI: 10.1242/jeb.043075] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2010] [Indexed: 11/20/2022]
Abstract
Myoglobin, a mobile carrier of oxygen, is without a doubt an important player central to the physiological function of heart and skeletal muscle. Recently, researchers have surmounted technical challenges to measure Mb diffusion in the living cell. Their observations have stimulated a discussion about the relative contribution made by Mb-facilitated diffusion to the total oxygen flux. The calculation of the relative contribution, however, depends upon assumptions, the cell model and cell architecture, cell bioenergetics, oxygen supply and demand. The analysis suggests that important differences can be observed whether steady-state or transient conditions are considered. This article reviews the current evidence underlying the evaluation of the biophysical parameters of myoglobin-facilitated oxygen diffusion in cells, specifically the intracellular concentration of myoglobin, the intracellular diffusion coefficient of myoglobin and the intracellular myoglobin oxygen saturation. The review considers the role of myoglobin in oxygen transport in vertebrate heart and skeletal muscle, in the diving seal during apnea as well as the role of the analogous leghemoglobin of plants. The possible role of myoglobin in intracellular fatty acid transport is addressed. Finally, the recent measurements of myoglobin diffusion inside muscle cells are discussed in terms of their implications for cytoarchitecture and microviscosity in these cells and the identification of intracellular impediments to the diffusion of proteins inside cells. The recent experimental data then help to refine our understanding of Mb function and establish a basis for future investigation.
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Affiliation(s)
- Gerolf Gros
- Zentrum Physiologie, Medizinische Hochschule Hannover, 30625 Hannover, Germany
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Tomita A, Kreutzer U, Adachi SI, Koshihara SY, Jue T. ‘It's hollow’: the function of pores within myoglobin. J Exp Biol 2010; 213:2748-54. [DOI: 10.1242/jeb.042994] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Despite a century of research, the cellular function of myoglobin (Mb), the mechanism regulating oxygen (O2) transport in the cell and the structure–function relationship of Mb remain incompletely understood. In particular, the presence and function of pores within Mb have attracted much recent attention. These pores can bind to Xe as well as to other ligands. Indeed, recent cryogenic X-ray crystallographic studies using novel techniques have captured snapshots of carbon monoxide (CO) migrating through these pores. The observed movement of the CO molecule from the heme iron site to the internal cavities and the associated structural changes of the amino acid residues around the cavities confirm the integral role of the pores in forming a ligand migration pathway from the protein surface to the heme. These observations resolve a long-standing controversy – but how these pores affect the physiological function of Mb poses a striking question at the frontier of biology.
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Affiliation(s)
- Ayana Tomita
- Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro-ku, Tokyo, 152-8551, Japan
- Non-equilibrium Dynamics Project, ERATO/JST, 1-1 O-ho, Tsukuba, Ibaraki 305-0801, Japan
| | - Ulrike Kreutzer
- Department of Biochemistry and Molecular Medicine, University of California Davis, CA 95616-8635, USA
| | - Shin-ichi Adachi
- Non-equilibrium Dynamics Project, ERATO/JST, 1-1 O-ho, Tsukuba, Ibaraki 305-0801, Japan
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 O-ho, Tsukuba, Ibaraki 305-0801, Japan
| | - Shin-ya Koshihara
- Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro-ku, Tokyo, 152-8551, Japan
- Non-equilibrium Dynamics Project, ERATO/JST, 1-1 O-ho, Tsukuba, Ibaraki 305-0801, Japan
| | - Thomas Jue
- Department of Biochemistry and Molecular Medicine, University of California Davis, CA 95616-8635, USA
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Kristiansen G, Rose M, Geisler C, Fritzsche FR, Gerhardt J, Lüke C, Ladhoff AM, Knüchel R, Dietel M, Moch H, Varga Z, Theurillat JP, Gorr TA, Dahl E. Endogenous myoglobin in human breast cancer is a hallmark of luminal cancer phenotype. Br J Cancer 2010; 102:1736-45. [PMID: 20531416 PMCID: PMC2883703 DOI: 10.1038/sj.bjc.6605702] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Background: We aimed to clarify the incidence and the clinicopathological value of non-muscle myoglobin (Mb) in a large cohort of non-invasive and invasive breast cancer cases. Methods: Matched pairs of breast tissues from 10 patients plus 17 breast cell lines were screened by quantitative PCR for Mb mRNA. In addition, 917 invasive and 155 non-invasive breast cancer cases were analysed by immunohistochemistry for Mb expression and correlated to clinicopathological parameters and basal molecular characteristics including oestrogen receptor-α (ERα)/progesteron receptor (PR)/HER2, fatty acid synthase (FASN), hypoxia-inducible factor-1α (HIF-1α), HIF-2α, glucose transporter 1 (GLUT1) and carbonic anhydrase IX (CAIX). The spatial relationship of Mb and ERα or FASN was followed up by double immunofluorescence. Finally, the effects of estradiol treatment and FASN inhibition on Mb expression in breast cancer cells were analysed. Results: Myoglobin mRNA was found in a subset of breast cancer cell lines; in microdissected tumours Mb transcript was markedly upregulated. In all, 71% of tumours displayed Mb protein expression in significant correlation with a positive hormone receptor status and better prognosis. In silico data mining confirmed higher Mb levels in luminal-type breast cancer. Myoglobin was also correlated to FASN, HIF-2α and CAIX, but not to HIF-1α or GLUT1, suggesting hypoxia to participate in its regulation. Double immunofluorescence showed a cellular co-expression of ERα or FASN and Mb. In addition, Mb levels were modulated on estradiol treatment and FASN inhibition in a cell model. Conclusion: We conclude that in breast cancer, Mb is co-expressed with ERα and co-regulated by oestrogen signalling and can be considered a hallmark of luminal breast cancer phenotype. This and its possible new role in fatty acid metabolism may have fundamental implications for our understanding of Mb in solid tumours.
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Affiliation(s)
- G Kristiansen
- Institute of Surgical Pathology, University Hospital Zurich, Schmelzbergstrasse 12, 8091 Zurich, Switzerland.
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Molojavyi A, Lindecke A, Raupach A, Moellendorf S, Köhrer K, Gödecke A. Myoglobin-deficient mice activate a distinct cardiac gene expression program in response to isoproterenol-induced hypertrophy. Physiol Genomics 2010; 41:137-45. [PMID: 20145201 DOI: 10.1152/physiolgenomics.90297.2008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Myoglobin knockout mice (myo-/-) adapt to the loss of myoglobin by the activation of a variety of compensatory mechanisms acting on the structural and functional level. To analyze to what extent myo-/- mice would tolerate cardiac stress we used the model of chronic isoproterenol application to induce cardiac hypertrophy in myo-/- mice and wild-type (WT) controls. After 14 days of isoproterenol infusion cardiac hypertrophy in WT and myo-/- mice reached a similar level. WT mice developed lung edema and left ventricular dilatation suggesting the development of heart failure. In contrast, myo-/- mice displayed conserved cardiac function and no signs of left ventricular dilatation. Analysis of the cardiac gene expression profiles using 40K mouse oligonucleotide arrays showed that isoproterenol affected the expression of 180 genes in WT but only 92 genes of myo-/- hearts. Only 40 of these genes were regulated in WT as well as in myo-/- hearts. In WT hearts a pronounced induction of genes of the extracellular matrix occurred suggesting a higher level of cardiac remodeling. myo-/- hearts showed altered transcription of genes involved in carbon metabolism, inhibition of apoptosis and muscular repair. Interestingly, a subset of genes that was altered in myo-/- mice already under basal conditions was differentially expressed in WT hearts under isoproterenol treatment. In summary, our data show a high capacity of myoglobin-deficient mice to adapt to catecholamine induced cardiac stress which is associated with activation of a distinct cardiac gene expression program.
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Affiliation(s)
- Andrei Molojavyi
- Institut für Herz- und Kreislaufphysiologie, Heinrich-Heine-Universität Düsseldorf, 40001 Düsseldorf, Germany
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van Faassen EE, Bahrami S, Feelisch M, Hogg N, Kelm M, Kim-Shapiro DB, Kozlov AV, Li H, Lundberg JO, Mason R, Nohl H, Rassaf T, Samouilov A, Slama-Schwok A, Shiva S, Vanin AF, Weitzberg E, Zweier J, Gladwin MT. Nitrite as regulator of hypoxic signaling in mammalian physiology. Med Res Rev 2009; 29:683-741. [PMID: 19219851 PMCID: PMC2725214 DOI: 10.1002/med.20151] [Citation(s) in RCA: 321] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In this review we consider the effects of endogenous and pharmacological levels of nitrite under conditions of hypoxia. In humans, the nitrite anion has long been considered as metastable intermediate in the oxidation of nitric oxide radicals to the stable metabolite nitrate. This oxidation cascade was thought to be irreversible under physiological conditions. However, a growing body of experimental observations attests that the presence of endogenous nitrite regulates a number of signaling events along the physiological and pathophysiological oxygen gradient. Hypoxic signaling events include vasodilation, modulation of mitochondrial respiration, and cytoprotection following ischemic insult. These phenomena are attributed to the reduction of nitrite anions to nitric oxide if local oxygen levels in tissues decrease. Recent research identified a growing list of enzymatic and nonenzymatic pathways for this endogenous reduction of nitrite. Additional direct signaling events not involving free nitric oxide are proposed. We here discuss the mechanisms and properties of these various pathways and the role played by the local concentration of free oxygen in the affected tissue.
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Affiliation(s)
- Ernst E van Faassen
- Department of Interface Physics, Debye Institute, Utrecht University, Princetonplein 1, 3508 TA Utrecht, The Netherlands.
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Roles of the creatine kinase system and myoglobin in maintaining energetic state in the working heart. BMC SYSTEMS BIOLOGY 2009; 3:22. [PMID: 19228404 PMCID: PMC2667476 DOI: 10.1186/1752-0509-3-22] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Accepted: 02/19/2009] [Indexed: 11/10/2022]
Abstract
BACKGROUND The heart is capable of maintaining contractile function despite a transient decrease in blood flow and increase in cardiac ATP demand during systole. This study analyzes a previously developed model of cardiac energetics and oxygen transport to understand the roles of the creatine kinase system and myoglobin in maintaining the ATP hydrolysis potential during beat-to-beat transient changes in blood flow and ATP hydrolysis rate. RESULTS The theoretical investigation demonstrates that elimination of myoglobin only slightly increases the predicted range of oscillation of cardiac oxygenation level during beat-to-beat transients in blood flow and ATP utilization. In silico elimination of myoglobin has almost no impact on the cytoplasmic ATP hydrolysis potential (DeltaGATPase). In contrast, disabling the creatine kinase system results in considerable oscillations of cytoplasmic ADP and ATP levels and seriously deteriorates the stability of DeltaGATPase in the beating heart. CONCLUSION The CK system stabilizes DeltaGATPase by both buffering ATP and ADP concentrations and enhancing the feedback signal of inorganic phosphate in regulating mitochondrial oxidative phosphorylation.
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Sriram R, Kreutzer U, Shih L, Jue T. Interaction of fatty acid with myoglobin. FEBS Lett 2008; 582:3643-9. [PMID: 18840435 DOI: 10.1016/j.febslet.2008.09.047] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 09/17/2008] [Accepted: 09/25/2008] [Indexed: 10/21/2022]
Abstract
Upon titration with palmitate, the (1)H NMR spectra of metmyoglobin cyanide (MbCN) reveal a selective perturbation of the 8 heme methyl, consistent with a specific interaction of myoglobin (Mb) with fatty acid. Other detectable hyperfine shifted resonances of the heme group remain unchanged. Mb also enhances fatty acid solubility, as reflected in a more intense methylene peak of palmitate in Mb solution than in Tris buffer. Ligand binding analysis indicates an apparent palmitate dissociation constant (K(d)) of 43microM. These results suggest that Mb can bind fatty acid and may have a role in facilitating fatty acid transport in the cell.
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Affiliation(s)
- Renuka Sriram
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA 95616-8635, USA
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44
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Levkau B, Schäfers M, Wohlschlaeger J, von Wnuck Lipinski K, Keul P, Hermann S, Kawaguchi N, Kirchhof P, Fabritz L, Stypmann J, Stegger L, Flögel U, Schrader J, Fischer JW, Fischer J, Hsieh P, Ou YL, Mehrhof F, Tiemann K, Ghanem A, Matus M, Neumann J, Heusch G, Schmid KW, Conway EM, Baba HA. Survivin determines cardiac function by controlling total cardiomyocyte number. Circulation 2008; 117:1583-93. [PMID: 18332262 DOI: 10.1161/circulationaha.107.734160] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Survivin inhibits apoptosis and regulates cell division in many organs, but its function in the heart is unknown. METHODS AND RESULTS We show that cardiac-specific deletion of survivin resulted in premature cardiac death. The underlying cause was a dramatic reduction in total cardiomyocyte numbers as determined by a stereological method for quantification of cells per organ. The resulting increased hemodynamic load per cell led to progressive heart failure as assessed by echocardiography, magnetic resonance imaging, positron emission tomography, and invasive catheterization. The reduction in total cardiomyocyte number in alpha-myosin heavy chain (MHC)-survivin(-/-) mice was due to an approximately 50% lower mitotic rate without increased apoptosis. This occurred at the expense of DNA accumulation because survivin-deficient cardiomyocytes displayed marked DNA polyploidy indicative of consecutive rounds of DNA replication without cell division. Survivin small interfering RNA knockdown in neonatal rat cardiomyocytes also led to polyploidization and cell cycle arrest without apoptosis. Adenoviral overexpression of survivin in cardiomyocytes inhibited doxorubicin-induced apoptosis, induced DNA synthesis, and promoted cell cycle progression. The phenotype of the alphaMHC-survivin(-/-) mice also allowed us to determine the minimum cardiomyocyte number sufficient for normal cardiac function. In human cardiomyopathy, survivin was potently induced in the failing heart and downregulated again after hemodynamic support by a left ventricular assist device. Its expression positively correlated with the mean cardiomyocyte DNA content. CONCLUSIONS We suggest that the ontogenetically determined cardiomyocyte number may be an independent factor in the susceptibility to cardiac diseases. Through its profound impact on both cardiomyocyte replication and apoptosis, survivin may emerge as a promising new target for myocardial regeneration.
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Affiliation(s)
- Bodo Levkau
- Institut für Pathophysiologie, Universitätsklinikum Essen, Essen Germany.
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Wittenberg JB, Wittenberg BA. Myoglobin-enhanced oxygen delivery to isolated cardiac mitochondria. J Exp Biol 2007; 210:2082-90. [PMID: 17562881 DOI: 10.1242/jeb.003947] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
The heart, red skeletal muscles and the nitrogen-fixing legume root nodule function in steady states of high oxygen influx, partial oxygenation of cytoplasmic myoglobin or leghemoglobin and correspondingly low oxygen partial pressure. Here, we ask: what conditions are required at the surface of actively respiring, state III, tightly coupled mitochondria to enhance oxygen flow to cytochrome oxidase? Pigeon heart mitochondria were isolated with minimal damage to the outer mitochondrial membrane and were incubated at low oxygen pressures, where respiration is oxygen limited, with solutions of each of six monomeric hemoglobins with widely divergent kinetics and equilibria in their reactions with oxygen: Busycon myoglobin, horse myoglobin, Lucina hemoglobins I and II, soybean leghemoglobin c and Gasterophilus hemoglobin. Each augments oxygen uptake. The declining fractional saturation of each hemoglobin with oxygen was monitored spectrophotometrically as mitochondrial respiration depleted the oxygen; the oxygen partial pressure at half-maximal rate of oxygen uptake was similar for each hemoglobin, supporting the conclusion that the hemoglobins did not interact with the mitochondrial surface in oxygen delivery. The oxygen pressure required to support state III mitochondrial oxygen uptake, 0.005 kPa (0.04 torr), is small compared with that obtained in the sarcoplasm and at the mitochondrial surface of the working heart, 0.32 kPa (2.4 torr). We conclude that, in normal steady states of contraction of the myoglobin-containing heart, oxygen utilization by mitochondrial cytochrome oxidase is not limited by oxygen availability.
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Affiliation(s)
- Jonathan B Wittenberg
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Khairallah M, Khairallah R, Young ME, Dyck JRB, Petrof BJ, Des Rosiers C. Metabolic and signaling alterations in dystrophin-deficient hearts precede overt cardiomyopathy. J Mol Cell Cardiol 2007; 43:119-29. [PMID: 17583724 DOI: 10.1016/j.yjmcc.2007.05.015] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Revised: 04/20/2007] [Accepted: 05/14/2007] [Indexed: 01/16/2023]
Abstract
The cytoskeletal protein dystrophin has been implicated in hereditary and acquired forms of cardiomyopathy. However, much remains to be learned about the role of dystrophin in the heart. We hypothesized that the dystrophin-deficient heart displays early alterations in energy metabolism that precede overt cardiomyopathy. We evaluated the metabolic and functional phenotype of dystrophin-deficient mdx mouse hearts at 10-12 weeks, when no major histological or echocardiographic abnormalities are reported. Ex vivo working mdx heart perfusions with stable isotopes revealed a marked shift in substrate fuel selection from fatty acids to carbohydrates associated with enhanced oxygen consumption. They also unmasked in the mdx heart: (i) compromised cardiac contractile function and efficiency, (ii) reduced cellular integrity, and (iii) exacerbated alterations in mitochondrial citric acid cycle-related parameters and in nutrient signaling pathways related to Akt. The observed shift in substrate selection cannot be explained by metabolic gene remodeling. However, mdx mice hearts showed an increased expression of the atrial natriuretic factor (anf) gene, an activator of the nitric oxide (NO)/cGMP signaling pathway and marker of cardiac remodeling, and, only as the cardiomyopathy progresses (at 25 weeks of age), an increased expression of the alpha1 subunit of soluble guanylate cyclase, which is known to negatively correlate with the activity NO/cGMP pathway. Collectively, our results highlight early metabolic and signaling alterations in the dystrophin-deficient heart, which may predispose these hearts to contractile dysfunction and sarcolemmal fragility. They also suggest the presence of a "sub-clinical" defect in the NO/cGMP pathway, which in vivo, at an early age, may be compensated by enhanced anf gene expression.
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Affiliation(s)
- Maya Khairallah
- Montreal Heart Institute and University of Montreal, 5000 Belanger St., Montreal, Quebec, Canada H1T 1C8
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Rassaf T, Flögel U, Drexhage C, Hendgen-Cotta U, Kelm M, Schrader J. Nitrite reductase function of deoxymyoglobin: oxygen sensor and regulator of cardiac energetics and function. Circ Res 2007; 100:1749-54. [PMID: 17495223 DOI: 10.1161/circresaha.107.152488] [Citation(s) in RCA: 235] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Although the primary function of myoglobin (Mb) has been considered to be cellular oxygen storage and supply, recent studies have suggested to classify Mb as a multifunctional allosteric enzyme. In the heart, Mb acts as a potent scavenger of nitric oxide (NO) and contributes to the attenuation of oxidative damage. Here we report that a dynamic cycle exists in which a decrease in tissue oxygen tension drives the conversion of Mb from being an NO scavenger in normoxia to an NO producer in hypoxia. The NO generated by reaction of deoxygenated Mb with nitrite is functionally relevant and leads to a downregulation of cardiac energy status, which was not observed in mice lacking Mb. As a consequence, myocardial oxygen consumption is reduced and cardiac contractility is dampened in wild-type mice. We propose that this pathway represents a novel homeostatic mechanism by which a mismatch between oxygen supply and demand in muscle is translated into the fractional increase of deoxygenated Mb exhibiting enhanced nitrite reductase activity. Thus, Mb may act as an oxygen sensor which through NO can adjust muscle energetics to limited oxygen supply.
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Affiliation(s)
- Tienush Rassaf
- University Hospital Aachen, Department of Medicine, Division of Cardiology, Pulmonary and Vascular Diseases, Aachen, Germany.
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Flögel U, Jacoby C, Gödecke A, Schrader J. In vivo 2D mapping of impaired murine cardiac energetics in NO-induced heart failure. Magn Reson Med 2007; 57:50-8. [PMID: 17139621 DOI: 10.1002/mrm.21101] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
(31)P MRS studies in humans have shown that an impairment of cardiac energetics is characteristic of heart failure. Although numerous transgenic mouse models with a heart-failure phenotype have been generated, current methods to analyze murine high-energy phosphates (HEPs) in vivo are hampered by limited spatial resolution. Using acquisition-weighted 2D (31)P chemical shift imaging (CSI) at 9.4 Tesla, we were able to acquire (31)P MR spectra over the entire thorax of the mouse with high spatial resolution in defined regions of the heart (the anterior, lateral, posterior, and septal walls) within a reasonable acquisition time of about 75 min. Analysis of a transgenic cardiomyopathy model (double mutant: cardiospecific inducible nitric oxide synthase (iNOS) overexpression and lack of myoglobin (tg-iNOS(+)/myo(-/-)) revealed that cardiac dysfunction in the mutant was associated with an impaired energy state (phosphocreatine (PCr)/adenosine triphosphate (ATP) 1.54 +/- 0.18) over the entire left ventricle (LV; wild-type (WT): PCr/ATP 2.06 +/- 0.22, N = 5, P < 0.05), indicating that in the absence of efficient cytosolic NO scavenging, iNOS-derived NO critically interferes with the respiratory chain. In vivo data were validated against (31)P MR spectra of perchloric acid extracts (PCr/ATP: 1.87 +/- 0.21 (WT), 1.39 +/- 0.17 (tg-iNOS(+)/myo(-/-), N = 5, P < 0.05). Future applications will substantially benefit studies on the cause-and-effect relationship between cardiac energetics and function in other genetically well-defined models of heart failure.
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Affiliation(s)
- Ulrich Flögel
- Institut für Herz und Kreislaufphysiologie, Universitätsklinikum Düsseldorf, Heinrich Heine Universität, Düsseldorf, Germany.
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