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Akama Y, Park EJ, Satoh-Takayama N, Ito A, Kawamoto E, Gaowa A, Matsuo E, Oikawa S, Saito M, Inoue S, Akimoto T, Suzuki K, Shimaoka M. Roles of programmed death-1 and muscle innate lymphoid cell-derived interleukin 13 in sepsis-induced intensive care unit-acquired weakness. J Cachexia Sarcopenia Muscle 2024. [PMID: 39016179 DOI: 10.1002/jcsm.13548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 06/13/2024] [Accepted: 06/25/2024] [Indexed: 07/18/2024] Open
Abstract
BACKGROUND Intensive care unit-acquired weakness (ICU-AW) is a syndrome characterized by a long-term muscle weakness often observed in sepsis-surviving patients during the chronic phase. Although ICU-AW is independently associated with increased mortality, effective therapies have yet to be established. Programmed death-1 (PD-1) inhibitors have attracted attention as potential treatments for reversing immune exhaustion in sepsis; however, its impact on ICU-AW remains to be elucidated. Here, we study how PD-1 deficiency affects sepsis-induced skeletal muscle dysfunction in a preclinical sepsis model. METHODS Chronic sepsis model was developed by treating wild-type (WT) and PD-1 knockout (KO) mice with caecal slurry, followed by resuscitation with antibiotics and saline. Mice were euthanized on days 15-17. Body weights, muscle weights, and limb muscle strengths were measured. Interleukin 13 (IL-13) and PD-1 expressions were examined by flow cytometry. Messenger RNA (mRNA) expressions of slow-twitch muscles were measured by reverse transcription and quantitative polymerase chain reaction (RT-qPCR). In an in vitro study, C2C12 myotubes were treated with lipopolysaccharide (LPS) and recombinant IL-13 followed by gene expression measurements. RESULTS WT septic mice exhibited decreased muscle weight (quadriceps, P < 0.01; gastrocnemius, P < 0.05; and tibialis anterior, P < 0.01) and long-term muscle weakness (P < 0.0001), whereas PD-1 KO septic mice did not exhibit any reduction in muscle weights and strengths. Slow-twitch specific mRNAs, including myoglobin (Mb), troponin I type 1 (Tnni1), and myosin heavy chain 7 (Myh7) were decreased in WT skeletal muscle (Mb, P < 0.0001; Tnni1, P < 0.05; and Myh7, P < 0.05) after sepsis induction, but mRNA expressions of Tnni1 and Myh7 were increased in PD-1 KO septic mice (Mb, not significant; Tnni1, P < 0.0001; and Myh7, P < 0.05). Treatment of C2C12 myotube cells with LPS decreased the expression of slow-twitch mRNAs, which was restored by IL-13 (Mb, P < 0.0001; Tnni1, P < 0.001; and Myh7, P < 0.05). IL-13 production was significantly higher in ILC2s compared to T cells in skeletal muscle (P < 0.05). IL-13-producing ILC2s in skeletal muscle were examined and found to increase in PD-1 KO septic mice, compared with WT septic mice (P < 0.05). ILC2-derived IL-13 was increased by PD-1 KO septic mice and thought to protect the muscles from experimental ICU-AW. CONCLUSIONS Long-term muscle weakness in experimental ICU-AW was ameliorated in PD-1 KO mice. ILC2-derived IL-13 production in skeletal muscles was increased in PD-1 KO mice, thereby suggesting that IL-13 alleviates muscle weakness during sepsis. This study demonstrates the effects of PD-1 blockade in preserving muscle strength during sepsis through an increase in ILC2-derived IL-13 and may be an attractive therapeutic target for sepsis-induced ICU-AW.
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Affiliation(s)
- Yuichi Akama
- Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, Tsu, Japan
- Department of Emergency and Critical Care Medicine, Mie University Graduate School of Medicine, Tsu, Japan
| | - Eun Jeong Park
- Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, Tsu, Japan
| | - Naoko Satoh-Takayama
- Precision Immune Regulation RIKEN Research Unit, Center for Integrative Medical Sciences, RIKEN, Yokohama, Japan
| | - Atsushi Ito
- Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, Tsu, Japan
- Department of Thoracic and Cardiovascular Surgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Eiji Kawamoto
- Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, Tsu, Japan
- Department of Emergency and Critical Care Medicine, Mie University Graduate School of Medicine, Tsu, Japan
| | - Arong Gaowa
- Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, Tsu, Japan
| | - Eri Matsuo
- Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, Tsu, Japan
| | - Satoshi Oikawa
- Faculty of Sport Sciences, Waseda University, Saitama, Japan
| | - Masafumi Saito
- Department of Disaster and Emergency and Critical Care Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shigeaki Inoue
- Department of Emergency and Critical Care Medicine, Wakayama Medical University, Wakayama, Japan
| | | | - Kei Suzuki
- Department of Emergency and Critical Care Medicine, Mie University Graduate School of Medicine, Tsu, Japan
| | - Motomu Shimaoka
- Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, Tsu, Japan
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Yu J, Guo T, Gupta A, Llano EM, Wajahat N, Slater S, Deng Q, Akbay EA, Shelton JM, Evers BM, Wu Z, Tzameli I, Pashos E, Minna JD, Iyengar P, Infante RE. Cancer Cachexia in STK11/LKB1 -mutated NSCLC is Dependent on Tumor-secreted GDF15. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.14.598891. [PMID: 38948776 PMCID: PMC11212884 DOI: 10.1101/2024.06.14.598891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Cachexia is a wasting syndrome comprised of adipose, muscle, and weight loss observed in cancer patients. Tumor loss-of-function mutations in STK11/LKB1 , a regulator of the energy sensor AMP-activated protein kinase, induce cancer cachexia (CC) in preclinical models and are associated with cancer-related weight loss in NSCLC patients. Here we characterized the relevance of the NSCLC-associated cachexia factor growth differentiation factor 15 (GDF15) in several patient-derived and genetically engineered STK11/LKB1 -mutant NSCLC cachexia lines. Both tumor mRNA expression and serum concentrations of tumor-derived GDF15 were significantly elevated in multiple mice transplanted with patient-derived STK11/LKB1 -mutated NSCLC lines. GDF15 neutralizing antibody administered to mice transplanted with patient- or mouse-derived STK11/LKB1 -mutated NSCLC lines suppressed cachexia-associated adipose loss, muscle atrophy, and changes in body weight. The silencing of GDF15 in multiple human NSCLC lines was also sufficient to eliminate in vivo circulating GDF15 levels and abrogate cachexia induction, suggesting that tumor and not host tissues represent a key source of GDF15 production in these cancer models. Finally, reconstitution of wild-type STK11/LKB1 in a human STK11/LKB1 loss-of-function NSCLC line that normally induces cachexia in vivo correlated with the absence of tumor-secreted GDF15 and rescue from the cachexia phenotype. The current data provide evidence for tumor-secreted GDF15 as a conduit and a therapeutic target through which NSCLCs with STK11/LKB1 loss-of-function mutations promote cachexia-associated wasting.
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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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Aboouf MA, Gorr TA, Hamdy NM, Gassmann M, Thiersch M. Myoglobin in Brown Adipose Tissue: A Multifaceted Player in Thermogenesis. Cells 2023; 12:2240. [PMID: 37759463 PMCID: PMC10526770 DOI: 10.3390/cells12182240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/01/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Brown adipose tissue (BAT) plays an important role in energy homeostasis by generating heat from chemical energy via uncoupled oxidative phosphorylation. Besides its high mitochondrial content and its exclusive expression of the uncoupling protein 1, another key feature of BAT is the high expression of myoglobin (MB), a heme-containing protein that typically binds oxygen, thereby facilitating the diffusion of the gas from cell membranes to mitochondria of muscle cells. In addition, MB also modulates nitric oxide (NO•) pools and can bind C16 and C18 fatty acids, which indicates a role in lipid metabolism. Recent studies in humans and mice implicated MB present in BAT in the regulation of lipid droplet morphology and fatty acid shuttling and composition, as well as mitochondrial oxidative metabolism. These functions suggest that MB plays an essential role in BAT energy metabolism and thermogenesis. In this review, we will discuss in detail the possible physiological roles played by MB in BAT thermogenesis along with the potential underlying molecular mechanisms and focus on the question of how BAT-MB expression is regulated and, in turn, how this globin regulates mitochondrial, lipid, and NO• metabolism. Finally, we present potential MB-mediated approaches to augment energy metabolism, which ultimately could help tackle different metabolic disorders.
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Affiliation(s)
- Mostafa A. Aboouf
- Institute of Veterinary Physiology, University of Zurich, 8057 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
- Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo 11566, Egypt
| | - Thomas A. Gorr
- Institute of Veterinary Physiology, University of Zurich, 8057 Zurich, Switzerland
| | - Nadia M. Hamdy
- Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo 11566, Egypt
| | - Max Gassmann
- Institute of Veterinary Physiology, University of Zurich, 8057 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| | - Markus Thiersch
- Institute of Veterinary Physiology, University of Zurich, 8057 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
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5
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Anishkin A, Adepu KK, Bhandari D, Adams SH, Chintapalli SV. Computational Analysis Reveals Unique Binding Patterns of Oxygenated and Deoxygenated Myoglobin to the Outer Mitochondrial Membrane. Biomolecules 2023; 13:1138. [PMID: 37509174 PMCID: PMC10377724 DOI: 10.3390/biom13071138] [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: 05/25/2023] [Revised: 06/26/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Myoglobin (Mb) interaction with the outer mitochondrial membrane (OMM) promotes oxygen (O2) release. However, comprehensive molecular details on specific contact regions of the OMM with oxygenated (oxy-) and deoxygenated (deoxy-)Mb are missing. We used molecular dynamics (MD) simulations to explore the interaction of oxy- and deoxy-Mb with the membrane lipids of the OMM in two lipid compositions: (a) a typical whole membrane on average, and (b) specifically the cardiolipin-enriched cristae region (contact site). Unrestrained relaxations showed that on average, both the oxy- and deoxy-Mb established more stable contacts with the lipids typical of the cristae contact site, then with those of the average OMM. However, in steered detachment simulations, deoxy-Mb clung more tightly to the average OMM, and oxy-Mb strongly preferred the contact sites of the OMM. The MD simulation analysis further indicated that a non-specific binding, mediated by local electrostatic interactions, existed between charged or polar groups of Mb and the membrane, for stable interaction. To the best of our knowledge, this is the first computational study providing the molecular details of the direct Mb-mitochondria interaction that assisted in distinguishing the preferred localization of oxy- and deoxy-Mb on the OMM. Our findings support the existing experimental evidence on Mb-mitochondrial association and shed more insights on Mb-mediated O2 transport for cellular bioenergetics.
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Affiliation(s)
- Andriy Anishkin
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Kiran Kumar Adepu
- Arkansas Children's Nutrition Center, Little Rock, AR 72202, USA
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | | | - Sean H Adams
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA 95616, USA
- Center for Alimentary and Metabolic Science, University of California Davis, Sacramento, CA 95616, USA
| | - Sree V Chintapalli
- Arkansas Children's Nutrition Center, Little Rock, AR 72202, USA
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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Zhang Y, Ramirez-Martinez A, Chen K, McAnally JR, Cai C, Durbacz MZ, Chemello F, Wang Z, Xu L, Bassel-Duby R, Liu N, Olson EN. Net39 protects muscle nuclei from mechanical stress during the pathogenesis of Emery-Dreifuss muscular dystrophy. J Clin Invest 2023; 133:e163333. [PMID: 37395273 PMCID: PMC10313361 DOI: 10.1172/jci163333] [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: 07/06/2022] [Accepted: 05/16/2023] [Indexed: 07/04/2023] Open
Abstract
Mutations in genes encoding nuclear envelope proteins lead to diseases known as nuclear envelopathies, characterized by skeletal muscle and heart abnormalities, such as Emery-Dreifuss muscular dystrophy (EDMD). The tissue-specific role of the nuclear envelope in the etiology of these diseases has not been extensively explored. We previously showed that global deletion of the muscle-specific nuclear envelope protein NET39 in mice leads to neonatal lethality due to skeletal muscle dysfunction. To study the potential role of the Net39 gene in adulthood, we generated a muscle-specific conditional knockout (cKO) of Net39 in mice. cKO mice recapitulated key skeletal muscle features of EDMD, including muscle wasting, impaired muscle contractility, abnormal myonuclear morphology, and DNA damage. The loss of Net39 rendered myoblasts hypersensitive to mechanical stretch, resulting in stretch-induced DNA damage. Net39 was downregulated in a mouse model of congenital myopathy, and restoration of Net39 expression through AAV gene delivery extended life span and ameliorated muscle abnormalities. These findings establish NET39 as a direct contributor to the pathogenesis of EDMD that acts by protecting against mechanical stress and DNA damage.
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Affiliation(s)
- Yichi Zhang
- Department of Molecular Biology
- Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center
| | - Andres Ramirez-Martinez
- Department of Molecular Biology
- Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center
| | - Kenian Chen
- Quantitative Biomedical Research Center, Peter O’Donnell Jr. School of Public Health, and
| | - John R. McAnally
- Department of Molecular Biology
- Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center
| | - Chunyu Cai
- Department of Pathology, University of Texas (UT) Southwestern Medical Center, Dallas, Texas, USA
| | - Mateusz Z. Durbacz
- Department of Molecular Biology
- Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center
| | - Francesco Chemello
- Department of Molecular Biology
- Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center
| | - Zhaoning Wang
- Department of Molecular Biology
- Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center
| | - Lin Xu
- Quantitative Biomedical Research Center, Peter O’Donnell Jr. School of Public Health, and
| | - Rhonda Bassel-Duby
- Department of Molecular Biology
- Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center
| | - Ning Liu
- Department of Molecular Biology
- Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center
| | - Eric N. Olson
- Department of Molecular Biology
- Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center
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7
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Pro-Apoptotic and Anti-Invasive Properties Underscore the Tumor-Suppressing Impact of Myoglobin on a Subset of Human Breast Cancer Cells. Int J Mol Sci 2022; 23:ijms231911483. [PMID: 36232784 PMCID: PMC9570501 DOI: 10.3390/ijms231911483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 09/21/2022] [Accepted: 09/23/2022] [Indexed: 11/17/2022] Open
Abstract
The expression of myoglobin (MB), well known as the oxygen storage and transport protein of myocytes, is a novel hallmark of the luminal subtype in breast cancer patients and correlates with better prognosis. The mechanisms by which MB impacts mammary tumorigenesis are hitherto unclear. We aimed to unravel this role by using CRISPR/Cas9 technology to generate MB-deficient clones of MCF7 and SKBR3 breast cancer cell lines and subsequently characterize them by transcriptomics plus molecular and functional analyses. As main findings, loss of MB at normoxia upregulated the expression of cell cyclins and increased cell survival, while it prevented apoptosis in MCF7 cells. Additionally, MB-deficient cells were less sensitive to doxorubicin but not ionizing radiation. Under hypoxia, the loss of MB enhanced the partial epithelial to mesenchymal transition, thus, augmenting the migratory and invasive behavior of cells. Notably, in human invasive mammary ductal carcinoma tissues, MB and apoptotic marker levels were positively correlated. In addition, MB protein expression in invasive ductal carcinomas was associated with a positive prognostic value, independent of the known tumor suppressor p53. In conclusion, we provide multiple lines of evidence that endogenous MB in cancer cells by itself exerts novel tumor-suppressive roles through which it can reduce cancer malignancy.
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Wen B, Zheng Z, Wang L, Qian X, Wang X, Chen Y, Bao J, Jiang Y, Ji K, Liu H. HIF-1α is essential for the augmentation of myometrial contractility during labor†. Biol Reprod 2022; 107:1540-1550. [PMID: 36094838 PMCID: PMC9752684 DOI: 10.1093/biolre/ioac174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/29/2022] [Accepted: 09/09/2022] [Indexed: 12/24/2022] Open
Abstract
Uterine contraction is crucial for a successful labor and the prevention of postpartum hemorrhage. It is enhanced by hypoxia; however, its underlying mechanisms are yet to be elucidated. In this study, transcriptomes revealed that hypoxia-inducible factor-1alpha was upregulated in laboring myometrial biopsies, while blockade of hypoxia-inducible factor-1alpha decreased the contractility of the myometrium and myocytes in vitro via small interfering RNA and the inhibitor, 2-methoxyestradiol. Chromatin immunoprecipitation sequencing revealed that hypoxia-inducible factor-1alpha directly binds to the genome of contraction-associated proteins: the promoter of Gja1 and Ptgs2, and the intron of Oxtr. Silencing the hypoxia-inducible factor-1alpha reduced the expression of Ptgs2, Gja1, and Oxtr. Furthermore, blockade of Gja1 or Ptgs2 led to a significant decrease in myometrial contractions in the hypoxic tissue model, whereas atosiban did not remarkably influence contractility. Our study demonstrates that hypoxia-inducible factor-1alpha is essential for promoting myometrial contractility under hypoxia by directly targeting Gja1 and Ptgs2, but not Oxtr. These findings help us to better understand the regulation of myometrial contractions under hypoxia and provide a promising strategy for labor management and postpartum hemorrhage treatment.
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Affiliation(s)
| | | | - Lele Wang
- Guangzhou Key Laboratory of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Xueya Qian
- Guangzhou Key Laboratory of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Xiaodi Wang
- Guangzhou Key Laboratory of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Yunshan Chen
- Guangzhou Key Laboratory of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Junjie Bao
- Guangzhou Key Laboratory of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Yanmin Jiang
- Guangzhou Key Laboratory of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Kaiyuan Ji
- Guangzhou Key Laboratory of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Huishu Liu
- Correspondence: Guangzhou Key Laboratory of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, No.9 Jinsui Road, Guangzhou, China. E-mail:
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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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Helfenrath K, Sauer M, Kamga M, Wisniewsky M, Burmester T, Fabrizius A. The More, the Merrier? Multiple Myoglobin Genes in Fish Species, Especially in Gray Bichir (Polypterus senegalus) and Reedfish (Erpetoichthys calabaricus). Genome Biol Evol 2021; 13:6237895. [PMID: 33871590 PMCID: PMC8480196 DOI: 10.1093/gbe/evab078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2021] [Indexed: 12/30/2022] Open
Abstract
The members of the globin superfamily are a classical model system to investigate gene evolution and their fates as well as the diversity of protein function. One of the best-known globins is myoglobin (Mb), which is mainly expressed in heart muscle and transports oxygen from the sarcolemma to the mitochondria. Most vertebrates harbor a single copy of the myoglobin gene, but some fish species have multiple myoglobin genes. Phylogenetic analyses indicate an independent emergence of multiple myoglobin genes, whereby the origin is mostly the last common ancestor of each order. By analyzing different transcriptome data sets, we found at least 15 multiple myoglobin genes in the polypterid gray bichir (Polypterus senegalus) and reedfish (Erpetoichthys calabaricus). In reedfish, the myoglobin genes are expressed in a broad range of tissues but show very different expression values. In contrast, the Mb genes of the gray bichir show a rather scattered expression pattern; only a few Mb genes were found expressed in the analyzed tissues. Both, gray bichir and reedfish possess lungs which enable them to inhabit shallow and swampy waters throughout tropical Africa with frequently fluctuating and low oxygen concentrations. The myoglobin repertoire probably reflects the molecular adaptation to these conditions. The sequence divergence, the substitution rate, and the different expression pattern of multiple myoglobin genes in gray bichir and reedfish imply different functions, probably through sub- and neofunctionalization during evolution.
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Affiliation(s)
| | - Markus Sauer
- Institute of Zoology, Biocenter Grindel, University
of Hamburg, Germany
| | - Michelle Kamga
- Institute of Zoology, Biocenter Grindel, University
of Hamburg, Germany
- Teaching Hospital Cologne, University
of Cologne, Cologne, Germany
| | | | | | - Andrej Fabrizius
- Institute of Zoology, Biocenter Grindel, University
of Hamburg, Germany
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11
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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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12
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Huang B, Jiao Y, Zhu Y, Ning Z, Ye Z, Li QX, Hu C, Wang C. Mdfi Promotes C2C12 Cell Differentiation and Positively Modulates Fast-to-Slow-Twitch Muscle Fiber Transformation. Front Cell Dev Biol 2021; 9:605875. [PMID: 33553177 PMCID: PMC7862576 DOI: 10.3389/fcell.2021.605875] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 01/04/2021] [Indexed: 12/22/2022] Open
Abstract
Muscle development requires myoblast differentiation and muscle fiber formation. Myod family inhibitor (Mdfi) inhibits myogenic regulatory factors in NIH3T3 cells, but how Mdfi regulates myoblast myogenic development is still unclear. In the present study, we constructed an Mdfi-overexpression (Mdfi-OE) C2C12 cell line by the CRISPR/Cas9 system and performed RNA-seq on Mdfi-OE and wild-type (WT) C2C12 cells. The RNA-seq results showed that the calcium signaling pathway was the most significant. We also established the regulatory networks of Mdfi-OE on C2C12 cell differentiation and muscle fiber type transformation and identified hub genes. Further, both RNA-seq and experimental verification demonstrated that Mdfi promoted C2C12 cell differentiation by upregulating the expression of Myod, Myog, and Myosin. We also found that the positive regulation of Mdfi on fast-to-slow-twitch muscle fiber transformation is mediated by Myod, Camk2b, and its downstream genes, such as Pgc1a, Pdk4, Cs, Cox4, Acadm, Acox1, Cycs, and Atp5a1. In conclusion, our results demonstrated that Mdfi promotes C2C12 cell differentiation and positively modulates fast-to-slow-twitch muscle fiber transformation. These findings further our understanding of the regulatory mechanisms of Mdfi in myogenic development and muscle fiber type transformation. Our results suggest potential therapeutic targets for muscle- and metabolic-related diseases.
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Affiliation(s)
- Bo Huang
- National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Yiren Jiao
- National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Yifan Zhu
- National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Zuocheng Ning
- National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Zijian Ye
- National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Qing X Li
- Department of Molecular Biosciences and Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Chingyuan Hu
- Department of Human Nutrition, Food and Animal Sciences, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Chong Wang
- National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
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13
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Poole DC, Copp SW, Colburn TD, Craig JC, Allen DL, Sturek M, O'Leary DS, Zucker IH, Musch TI. Guidelines for animal exercise and training protocols for cardiovascular studies. Am J Physiol Heart Circ Physiol 2020; 318:H1100-H1138. [PMID: 32196357 DOI: 10.1152/ajpheart.00697.2019] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Whole body exercise tolerance is the consummate example of integrative physiological function among the metabolic, neuromuscular, cardiovascular, and respiratory systems. Depending on the animal selected, the energetic demands and flux through the oxygen transport system can increase two orders of magnitude from rest to maximal exercise. Thus, animal models in health and disease present the scientist with flexible, powerful, and, in some instances, purpose-built tools to explore the mechanistic bases for physiological function and help unveil the causes for pathological or age-related exercise intolerance. Elegant experimental designs and analyses of kinetic parameters and steady-state responses permit acute and chronic exercise paradigms to identify therapeutic targets for drug development in disease and also present the opportunity to test the efficacy of pharmacological and behavioral countermeasures during aging, for example. However, for this promise to be fully realized, the correct or optimal animal model must be selected in conjunction with reproducible tests of physiological function (e.g., exercise capacity and maximal oxygen uptake) that can be compared equitably across laboratories, clinics, and other proving grounds. Rigorously controlled animal exercise and training studies constitute the foundation of translational research. This review presents the most commonly selected animal models with guidelines for their use and obtaining reproducible results and, crucially, translates state-of-the-art techniques and procedures developed on humans to those animal models.
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Affiliation(s)
- David C Poole
- Department of Kinesiology, Kansas State University, Manhattan, Kansas.,Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas
| | - Steven W Copp
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Trenton D Colburn
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Jesse C Craig
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - David L Allen
- Department of Psychology and Neuroscience, University of Colorado, Boulder, Colorado
| | - Michael Sturek
- Department of Anatomy, Cell Biology and Physiology, Indiana University, Indianapolis, Indiana
| | - Donal S O'Leary
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Irving H Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Timothy I Musch
- Department of Kinesiology, Kansas State University, Manhattan, Kansas.,Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas
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14
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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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15
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Poole DC. Edward F. Adolph Distinguished Lecture. Contemporary model of muscle microcirculation: gateway to function and dysfunction. J Appl Physiol (1985) 2019; 127:1012-1033. [PMID: 31095460 DOI: 10.1152/japplphysiol.00013.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This review strikes at the very heart of how the microcirculation functions to facilitate blood-tissue oxygen, substrate, and metabolite fluxes in skeletal muscle. Contemporary evidence, marshalled from animals and humans using the latest techniques, challenges iconic perspectives that have changed little over the past century. Those perspectives include the following: the presence of contractile or collapsible capillaries in muscle, unitary control by precapillary sphincters, capillary recruitment at the onset of contractions, and the notion of capillary-to-mitochondrial diffusion distances as limiting O2 delivery. Today a wealth of physiological, morphological, and intravital microscopy evidence presents a completely different picture of microcirculatory control. Specifically, capillary red blood cell (RBC) and plasma flux is controlled primarily at the arteriolar level with most capillaries, in healthy muscle, supporting at least some flow at rest. In healthy skeletal muscle, this permits substrate access (whether carried in RBCs or plasma) to a prodigious total capillary surface area. Pathologies such as heart failure or diabetes decrease access to that exchange surface by reducing the proportion of flowing capillaries at rest and during exercise. Capillary morphology and function vary disparately among tissues. The contemporary model of capillary function explains how, following the onset of exercise, muscle O2 uptake kinetics can be extremely fast in health but slowed in heart failure and diabetes impairing contractile function and exercise tolerance. It is argued that adoption of this model is fundamental for understanding microvascular function and dysfunction and, as such, to the design and evaluation of effective therapeutic strategies to improve exercise tolerance and decrease morbidity and mortality in disease.
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Affiliation(s)
- David C Poole
- Departments of Kinesiology, Anatomy and Physiology, Kansas State University, Manhattan, Kansas
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16
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Mannino MH, Patel RS, Eccardt AM, Perez Magnelli RA, Robinson CLC, Janowiak BE, Warren DE, Fisher JS. Myoglobin as a versatile peroxidase: Implications for a more important role for vertebrate striated muscle in antioxidant defense. Comp Biochem Physiol B Biochem Mol Biol 2019; 234:9-17. [PMID: 31051268 DOI: 10.1016/j.cbpb.2019.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/29/2019] [Accepted: 04/23/2019] [Indexed: 12/17/2022]
Abstract
Myoglobins (Mb) are ubiquitous proteins found in striated muscle of nearly all vertebrate taxa. Although their function is most commonly associated with facilitating oxygen storage and diffusion, Mb has also been implicated in cellular antioxidant defense. The oxidized (Fe3+) form of Mb (metMB) can react with hydrogen peroxide (H2O2) to produce ferrylMb. FerrylMb can be reduced back to metMb for another round of reaction with H2O2. In the present study, we have shown that horse skeletal muscle Mb displays peroxidase activity using 2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) and 3,3',5,5'-tetramethylbenzidine (TMB) as reducing substrates, as well as the biologically-relevant substrates NADH/NADPH, ascorbate, caffeic acid, and resveratrol. We have also shown that ferrylMb can be reduced by both ethanol and acetaldehyde, which are known to accumulate in some vertebrate tissues under anaerobic conditions, such as anoxic goldfish and crucian carp, implying a potential mechanism for ethanol detoxification in striated muscle. We found that metMb peroxidase activity is pH-dependent, increasing as pH decreases from 7.4 to 6.1, which is biologically relevant to anaerobic vertebrate muscle when incurring intracellular lactic acidosis. Finally, we found that metMb reacts with hypochlorite in a heme-dependent fashion, indicating that Mb could play a role in hypochlorite detoxification. Taken together, these data suggest that Mb peroxidase activity might be an important antioxidant mechanism in vertebrate cardiac and skeletal muscle under a variety of physiological conditions, such as those that might occur in contracting skeletal muscle or during hypoxia.
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17
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Bock JM, Kruse NT, Donnelly C, Hirai DM, Craig JC, Colburn TD, Musch TI, Poole DC, Rosenberry R, Tian F, Liu H, Nelson MD, Piknova B, Willis WT, Zuo L, Zhou T, Riveros-Rivera A, Cristancho E, Gunga HC. Commentaries on Viewpoint: Managing the power grid: How myoglobin can regulate Po 2 and energy distribution in skeletal muscle. J Appl Physiol (1985) 2019; 126:791-794. [PMID: 30907709 DOI: 10.1152/japplphysiol.01107.2018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Joshua M Bock
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa
| | - Nicholas T Kruse
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Chris Donnelly
- Institute of Sport Sciences and Department of Physiology, University of Lausanne, Switzerland
| | - Daniel M Hirai
- Department of Health and Kinesiology, Purdue University, West Lafayette, Indiana
| | - Jesse C Craig
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah,Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, Utah
| | - Trenton D Colburn
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Timothy I Musch
- Department of Kinesiology, Kansas State University, Manhattan, Kansas,Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas
| | - David C Poole
- Department of Kinesiology, Kansas State University, Manhattan, Kansas,Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas
| | - Ryan Rosenberry
- Department of Kinesiology, University of Texas at Arlington, Texas
| | - Fenghua Tian
- Department of Bioengineering, University of Texas at Arlington, Texas
| | - Hanli Liu
- Department of Bioengineering, University of Texas at Arlington, Texas
| | - Michael D Nelson
- Department of Kinesiology, University of Texas at Arlington, Texas,Department of Bioengineering, University of Texas at Arlington, Texas
| | - Barbora Piknova
- Molecular Medicine Branch, NIDDK National Institutes of Health, Bethesda, Maryland
| | | | - Li Zuo
- Radiologic Sciences and Respiratory Therapy Division, School of Health and Rehabilitation Sciences, The Ohio State University College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio,Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, Ohio,Department of Biology, University of Maine, Presque Isle, Maine
| | - Tingyang Zhou
- Radiologic Sciences and Respiratory Therapy Division, School of Health and Rehabilitation Sciences, The Ohio State University College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio,Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, Ohio
| | - Alain Riveros-Rivera
- Institute of Physiology, Center for Space Medicine and Extreme Environments, Charité - Universitätsmedizin Berlin, Germany
| | - Edgar Cristancho
- Department of Biology. Universidad Nacional de Colombia. Bogotá, Colombia
| | - Hanns-Christian Gunga
- Institute of Physiology, Center for Space Medicine and Extreme Environments, Charité - Universitätsmedizin Berlin, Germany
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18
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Hirai DM, Colburn TD, Craig JC, Hotta K, Kano Y, Musch TI, Poole DC. Skeletal muscle interstitial O 2 pressures: bridging the gap between the capillary and myocyte. Microcirculation 2018; 26:e12497. [PMID: 30120845 DOI: 10.1111/micc.12497] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 07/26/2018] [Accepted: 08/13/2018] [Indexed: 01/18/2023]
Abstract
The oxygen transport pathway from air to mitochondria involves a series of transfer steps within closely integrated systems (pulmonary, cardiovascular, and tissue metabolic). Small and finite O2 stores in most mammalian species require exquisitely controlled changes in O2 flux rates to support elevated ATP turnover. This is especially true for the contracting skeletal muscle where O2 requirements may increase two orders of magnitude above rest. This brief review focuses on the mechanistic bases for increased microvascular blood-myocyte O2 flux (V̇O2 ) from rest to contractions. Fick's law dictates that V̇O2 elevations driven by muscle contractions are produced by commensurate changes in driving force (ie, O2 pressure gradients; ΔPO2 ) and/or effective diffusing capacity (DO2 ). While previous evidence indicates that increased DO2 helps modulate contracting muscle O2 flux, up until recently the role of the dynamic ΔPO2 across the capillary wall was unknown. Recent phosphorescence quenching investigations of both microvascular and novel interstitial PO2 kinetics in health have resolved an important step in the O2 cascade between the capillary and myocyte. Specifically, the significant transmural ΔPO2 at rest was sustained (but not increased) during submaximal contractions. This supports the contention that the blood-myocyte interface provides a substantial effective resistance to O2 diffusion and underscores that modulations in erythrocyte hemodynamics and distribution (DO2 ) are crucial to preserve the driving force for O2 flux across the capillary wall (ΔPO2 ) during contractions. Investigation of the O2 transport pathway close to muscle mitochondria is key to identifying disease mechanisms and develop therapeutic approaches to ameliorate dysfunction and exercise intolerance.
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Affiliation(s)
- Daniel M Hirai
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, Kansas
| | - Trenton D Colburn
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, Kansas
| | - Jesse C Craig
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, Kansas
| | - Kazuki Hotta
- Department of Engineering Science, University of Electro-Communications, Tokyo, Japan
| | - Yutaka Kano
- Department of Engineering Science, University of Electro-Communications, Tokyo, Japan
| | - Timothy I Musch
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, Kansas
| | - David C Poole
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, Kansas
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19
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Postnikova GB, Shekhovtsova EA. Myoglobin: Oxygen Depot or Oxygen Transporter to Mitochondria? A Novel Mechanism of Myoglobin Deoxygenation in Cells (review). BIOCHEMISTRY (MOSCOW) 2018; 83:168-183. [PMID: 29618303 DOI: 10.1134/s0006297918020098] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In this review, we shortly summarize the data of our studies (and also corresponding studies of other authors) on the new mechanism of myoglobin (Mb) deoxygenation in a cell, according to which Mb acts as an oxygen transporter, and its affinity for the ligand, like in other transporting proteins, is regulated by the interaction with the target, in our case, mitochondria (Mch). We firstly found that contrary to previously formulated and commonly accepted concepts, oxymyoglobin (MbO2) deoxygenation occurs only via interaction of the protein with respiring mitochondria (low pO2 values are necessary but not sufficient for this process to proceed). Detailed studies of the mechanism of Mb-Mch interaction by various physicochemical methods using natural and artificial bilayer phospholipid membranes showed that: (i) the rate of MbO2 deoxygenation in the presence of respiring Mch fully coincides with the rate of O2 uptake by mitochondria from a solution irrespectively of their state (native coupled, freshly frozen, or FCCP-uncoupled), i.e. it is determined by the respiratory activity of Mch; (ii) Mb nonspecifically binds to membrane phospholipids of the outer mitochondrial membrane, while any Mb-specific protein or phospholipid sites on it are lacking; (iii) oxygen uptake by Mch from a solution and the uptake of Mb-bound oxygen are two different processes, as their rates are differently affected by proteins (e.g. lysozyme) that compete with MbO2 for binding to the mitochondrial membrane; (iv) electrostatic forces significantly contribute to the Mb-membrane interactions; the dependence of these interactions on ionic strength is provided by the local electrostatic interactions between anionic groups of phospholipids (the heads) and invariant Lys and Arg residues near the Mb heme pocket; (v) interactions of Mb with phospholipid membranes promote conformational changes in the protein, primarily in its heme pocket, without significant alterations in the protein secondary and tertiary structures; and (vi) Mb-membrane interactions lead to decrease in the affinity of myoglobin for O2, which could be monitored by the increase in the MbO2 autooxidation rate under aerobic conditions and under anaerobic ones, by the shift in the MbO2/Mb(2) equilibrium towards the ligand-free protein. The decrease in the affinity of Mb for the ligand should facilitate O2 dissociation from MbO2 at physiological pO2 values in cells.
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Affiliation(s)
- G B Postnikova
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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20
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Zhang L, Zhou Y, Wu W, Hou L, Chen H, Zuo B, Xiong Y, Yang J. Skeletal Muscle-Specific Overexpression of PGC-1α Induces Fiber-Type Conversion through Enhanced Mitochondrial Respiration and Fatty Acid Oxidation in Mice and Pigs. Int J Biol Sci 2017; 13:1152-1162. [PMID: 29104506 PMCID: PMC5666330 DOI: 10.7150/ijbs.20132] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/17/2017] [Indexed: 11/11/2022] Open
Abstract
Individual skeletal muscles in the animal body are heterogeneous, as each is comprised of different fiber types. Type I muscle fibers are rich with mitochondria, and have high oxidative metabolisms while type IIB fibers have few mitochondria and high glycolytic metabolic capacity. Peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α), a transcriptional co-activator that regulates mitochondrial biogenesis and respiratory function, is implicated in muscle fiber-type switching. Over-expression of PGC-1α in transgenic mice increased the proportion of red/oxidative type I fiber. During pig muscle growth, an increased number of type I fibers can give meat more red color. To explore the roles of PGC-1α in regulation of muscle fiber type conversion, we generated skeletal muscle-specific PGC-1α transgenic mice and pig. Ectopic over-expression of PGC-1α was detected in both fast and slow muscle fibers. The transgenic animals displayed a remarkable amount of red/oxidative muscle fibers in major skeletal muscle tissues. Skeletal muscles from transgenic mice and pigs have increased expression levels of oxidative fiber markers such as MHC1, MHC2x, myoglobin and Tnni1, and decreased expressions of glycolytic fiber genes (MHC2a, MHC2b, CASQ-1 and Tnni2). The genes responsible for the TCA cycle and oxidative phosphorylation, cytochrome coxidase 2 and 4, and citrate synthase were also increased in the transgenic mice and pigs. These results suggested that transgenic over-expressed PGC-1α significantly increased muscle mitochondrial biogenesis, resulting in qualitative changes from glycolytic to oxidative energy generation. The transgenic animals also had elevated levels of PDK4 and PPARγ proteins in muscle tissue, which can lead to increased glycogen deposition and fatty acid oxidation. Therefore, the results support a significant role of PGC-1α in conversion of fast glycolytic fibers to slow and oxidative fiber through enhanced mitochondrial respiration and fatty acid oxidation, and transgenic over-expression of PGC-1α in skeletal muscle leads to more red meat production in pigs.
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Affiliation(s)
- Lin Zhang
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture, College of Animal Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Ying Zhou
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture, College of Animal Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Wangjun Wu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Liming Hou
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture, College of Animal Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Hongxing Chen
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Bo Zuo
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture, College of Animal Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Yuanzhu Xiong
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture, College of Animal Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Jinzeng Yang
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture, College of Animal Sciences, Huazhong Agricultural University, Wuhan 430070, China.,Department of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
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21
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Baum O, Jentsch L, Odriozola A, Tschanz SA, Olfert IM. Ultrastructure of Skeletal Muscles in Mice Lacking Muscle‐Specific VEGF Expression. Anat Rec (Hoboken) 2017; 300:2239-2249. [DOI: 10.1002/ar.23644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 04/11/2017] [Accepted: 04/30/2017] [Indexed: 01/22/2023]
Affiliation(s)
- Oliver Baum
- Institute of Physiology, Charité‐Universitätsmedizin BerlinBerlin Germany
| | - Lena Jentsch
- Institute of Anatomy, University of BernBern Switzerland
| | | | | | - I. Mark Olfert
- West Virginia Clinical and Translational Institute, Department of Exercise PhysiologyWest Virginia University School of MedicineMorgantown West Virginia
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XIE HC, LI JG, HE JP. Differential Responsiveness in VEGF Receptor Subtypes to Hypoxic Stress in Various Tissues of Plateau Animals. Physiol Res 2017; 66:357-362. [DOI: 10.33549/physiolres.933408] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
With hypoxic stress, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) are elevated and their responses are altered in skeletal muscles of plateau animals [China Qinghai-Tibetan plateau pikas (Ochotona curzoniae)] as compared with control animals [normal lowland Sprague-Dawley (SD) rats]. The results indicate that HIF-1α and VEGF are engaged in physiological functions under hypoxic environment. The purpose of the current study was to examine the protein levels of VEGF receptor subtypes (VEGFRs: VEGFR-1, VEGFR-2 and VEGFR-3) in the end organs, namely skeletal muscle, heart and lung in response to hypoxic stress. ELISA and Western blot analysis were employed to determine HIF-1α and the protein expression of VEGFRs in control animals and plateau pikas. We further blocked HIF-1α signal to determine if HIF-1α regulates alternations in VEGFRs in those tissues. We hypothesized that responsiveness of VEGFRs in the major end organs of plateau animals is differential with insult of hypoxic stress and is modulated by low oxygen sensitive HIF-1α. Our results show that hypoxic stress induced by exposure of lower O2 for 6 h significantly increased the levels of VEGFR-2 in skeletal muscle, heart and lung and the increases were amplified in plateau pikas. Our results also demonstrate that hypoxic stress enhanced VEGFR-3 in lungs of plateau animals. Nonetheless, no significant alternations in VEGFR-1 were observed in those tissues with hypoxic stress. Moreover, we observed decreases of VEGFR-2 in skeletal muscle, heart and lung; and decreases of VEGFR-3 in lung following HIF-1α inhibition. Overall, our findings suggest that in plateau animals 1) responsiveness of VEGFRs is different under hypoxic environment; 2) amplified VEGFR-2 response appears in skeletal muscle, heart and lung, and enhanced VEGFR-3 response is mainly observed in lung; 3) HIF-1α plays a regulatory role in the levels of VEGFRs. Our results provide the underlying cellular and molecular mechanisms responsible for hypoxic environment in plateau animals, having an impact on research of physiological and ecological adaptive responses to acute or chronic hypoxic stress in humans who living at high attitude and who live at a normal sea level but suffer from hypoxic disorders.
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Affiliation(s)
| | | | - J.-P. HE
- College of Life Science, Shaanxi Normal University, Xi'an, China
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23
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Knapp AE, Goldberg D, Delavar H, Trisko BM, Tang K, Hogan MC, Wagner PD, Breen EC. Skeletal myofiber VEGF regulates contraction-induced perfusion and exercise capacity but not muscle capillarity in adult mice. Am J Physiol Regul Integr Comp Physiol 2016; 311:R192-9. [PMID: 27225953 DOI: 10.1152/ajpregu.00533.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 05/17/2016] [Indexed: 11/22/2022]
Abstract
A single bout of exhaustive exercise signals expression of vascular endothelial growth factor (VEGF) in the exercising muscle. Previous studies have reported that mice with life-long deletion of skeletal myofiber VEGF have fewer capillaries and a severe reduction in endurance exercise. However, in adult mice, VEGF gene deletion conditionally targeted to skeletal myofibers limits exercise capacity without evidence of capillary regression. To explain this, we hypothesized that adult skeletal myofiber VEGF acutely regulates skeletal muscle perfusion during muscle contraction. A tamoxifen-inducible skeletal myofiber-specific VEGF gene deletion mouse (skmVEGF-/-) was used to reduce skeletal muscle VEGF protein by 90% in adult mice. Three weeks after inducing deletion of the skeletal myofiber VEGF gene, skmVEGF-/- mice exhibited diminished maximum running speed (-10%, P < 0.05) and endurance capacity (-47%; P < 0.05), which did not persist after 8 wk. In skmVEGF-/- mice, gastrocnemius complex time to fatigue measured in situ was 71% lower than control mice. Contraction-induced perfusion measured by optical imaging during a period of electrically stimulated muscle contraction was 85% lower in skmVEGF-/- than control mice. No evidence of capillary rarefication was detected in the soleus, gastrocnemius, and extensor digitorum longus (EDL) up to 8 wk after tamoxifen-induced VEGF ablation, and contractility and fatigue resistance of the soleus measured ex vivo were also unchanged. The force-frequency of the EDL showed a small right shift, but fatigue resistance did not differ between EDL from control and skmVEGF-/- mice. These data suggest myofiber VEGF is required for regulating perfusion during periods of contraction and may in this manner affect endurance capacity.
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Affiliation(s)
- Amy E Knapp
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Daniel Goldberg
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Hamid Delavar
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Breanna M Trisko
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Kechun Tang
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Michael C Hogan
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Peter D Wagner
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Ellen C Breen
- Department of Medicine, University of California, San Diego, La Jolla, California
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Abstract
Neuromuscular diseases can affect the survival of peripheral neurons, their axons extending to peripheral targets, their synaptic connections onto those targets, or the targets themselves. Examples include motor neuron diseases such as Amyotrophic Lateral Sclerosis, peripheral neuropathies such as Charcot-Marie-Tooth diseases, myasthenias, and muscular dystrophies. Characterizing these phenotypes in mouse models requires an integrated approach, examining both the nerve and muscle histologically, anatomically, and functionally by electrophysiology. Defects observed at these levels can be related back to onset, severity, and progression, as assessed by "Quality of life measures" including tests of gross motor performance such as gait or grip strength. This chapter describes methods for assessing neuromuscular disease models in mice, and how interpretation of these tests can be complicated by the inter-relatedness of the phenotypes.
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Affiliation(s)
- Robert W Burgess
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA.
| | - Gregory A Cox
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA
| | - Kevin L Seburn
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA
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Yamada T, Takakura H, Jue T, Hashimoto T, Ishizawa R, Furuichi Y, Kato Y, Iwanaka N, Masuda K. Myoglobin and the regulation of mitochondrial respiratory chain complex IV. J Physiol 2015; 594:483-95. [PMID: 26584944 DOI: 10.1113/jp270824] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 11/13/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Mitochondrial respiration is regulated by multiple elaborate mechanisms. It has been shown that muscle specific O2 binding protein, Myoglobin (Mb), is localized in mitochondria and interacts with respiratory chain complex IV, suggesting that Mb could be a factor that regulates mitochondrial respiration. Here, we demonstrate that muscle mitochondrial respiration is improved by Mb overexpression via up-regulation of complex IV activity in cultured myoblasts; in contrast, suppression of Mb expression induces a decrease in complex IV activity and mitochondrial respiration compared with the overexpression model. The present data are the first to show the biological significance of mitochondrial Mb as a potential modulator of mitochondrial respiratory capacity. ABSTRACT Mitochondria are important organelles for metabolism, and their respiratory capacity is a primary factor in the regulation of energy expenditure. Deficiencies of cytochrome c oxidase complex IV, which reduces O2 in mitochondria, are linked to several diseases, such as mitochondrial myopathy. Moreover, mitochondrial respiration in skeletal muscle tissue tends to be susceptible to complex IV activity. Recently, we showed that the muscle-specific protein myoglobin (Mb) interacts with complex IV. The precise roles of mitochondrial Mb remain unclear. Here, we demonstrate that Mb facilitates mitochondrial respiratory capacity in skeletal muscles. Although mitochondrial DNA copy numbers were not altered in Mb-overexpressing myotubes, O2 consumption was greater in these myotubes than that in mock cells (Mock vs. Mb-Flag::GFP: state 4, 1.00 ± 0.09 vs. 1.77 ± 0.34; state 3, 1.00 ± 0.29; Mock: 1.60 ± 0.53; complex 2-3-4: 1.00 ± 0.30 vs. 1.50 ± 0.44; complex IV: 1.00 ± 0.14 vs. 1.87 ± 0.27). This improvement in respiratory capacity could be because of the activation of enzymatic activity of respiratory complexes. Moreover, mitochondrial respiration was up-regulated in myoblasts transiently overexpressing Mb; complex IV activity was solely activated in Mb-overexpressing myoblasts, and complex IV activity was decreased in the myoblasts in which Mb expression was suppressed by Mb-siRNA transfection (Mb vector transfected vs. Mb vector, control siRNA transfected vs. Mb vector, Mb siRNA transfected: 0.15 vs. 0.15 vs. 0.06). Therefore, Mb enhances the enzymatic activity of complex IV to ameliorate mitochondrial respiratory capacity, and could play a pivotal role in skeletal muscle metabolism.
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Affiliation(s)
- Tatsuya Yamada
- Faculty of Human Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Hisashi Takakura
- Faculty of Health and Sports Science, Doshisha University, Kyotanabe, 610-0394, Japan
| | - Thomas Jue
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, 95616-8635, CA, USA
| | - Takeshi Hashimoto
- Faculty of Sports Sciences, Ritsumeikan University, Kusatsu, 525-8577, Japan
| | - Rie Ishizawa
- Faculty of Human Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Yasuro Furuichi
- Department of Health Promotion Science, Tokyo Metropolitan University, Hachioji, 192-0397, Japan
| | - Yukio Kato
- Faculty of Pharmacy, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Nobumasa Iwanaka
- Faculty of Sports Sciences, Ritsumeikan University, Kusatsu, 525-8577, Japan
| | - Kazumi Masuda
- Faculty of Human Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
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26
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Glancy B, Hsu LY, Dao L, Bakalar M, French S, Chess DJ, Taylor JL, Picard M, Aponte A, Daniels MP, Esfahani S, Cushman S, Balaban RS. In vivo microscopy reveals extensive embedding of capillaries within the sarcolemma of skeletal muscle fibers. Microcirculation 2015; 21:131-47. [PMID: 25279425 DOI: 10.1111/micc.12098] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 10/03/2013] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To provide insight into mitochondrial function in vivo, we evaluated the 3D spatial relationship between capillaries, mitochondria, and muscle fibers in live mice. METHODS 3D volumes of in vivo murine TA muscles were imaged by MPM. Muscle fiber type, mitochondrial distribution, number of capillaries, and capillary-to-fiber contact were assessed. The role of Mb-facilitated diffusion was examined in Mb KO mice. Distribution of GLUT4 was also evaluated in the context of the capillary and mitochondrial network. RESULTS MPM revealed that 43.6 ± 3.3% of oxidative fiber capillaries had ≥50% of their circumference embedded in a groove in the sarcolemma, in vivo. Embedded capillaries were tightly associated with dense mitochondrial populations lateral to capillary grooves and nearly absent below the groove. Mitochondrial distribution, number of embedded capillaries, and capillary-to-fiber contact were proportional to fiber oxidative capacity and unaffected by Mb KO. GLUT4 did not preferentially localize to embedded capillaries. CONCLUSIONS Embedding capillaries in the sarcolemma may provide a regulatory mechanism to optimize delivery of oxygen to heterogeneous groups of muscle fibers. We hypothesize that mitochondria locate to PV regions due to myofibril voids created by embedded capillaries, not to enhance the delivery of oxygen to the mitochondria.
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Affiliation(s)
- Brian Glancy
- Laboratory of Cardiac Energetics, NHLBI, Bethesda, Maryland, USA
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27
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XIE HC, HE JP, ZHU JF, LI JG. Expression of HIF-1α and VEGF in Skeletal Muscle of Plateau Animals in Response to Hypoxic Stress. Physiol Res 2014; 63:801-5. [DOI: 10.33549/physiolres.932849] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Hypoxia-inducible factor-1α (HIF-1α) transcriptionally regulates expression of several target genes in protecting tissues against hypoxia. With hypoxic stress, vascular endothelial growth factor (VEGF) is a signal protein produced by cells and further contributes to improvement of vascular functions and restoring the oxygen supply to tissues. In this current study, we first hypothesized that the protein levels of HIF-1α and VEGF are reduced in skeletal muscles of plateau animals [China Qinghai-Tibetan plateau pikas (ochotona curzoniae)] in response to hypoxia as compared with control animals [normal lowland Sprague-Dawley (SD) rats]. We further hypothesized that HIF-1α plays a role in regulating expression of VEGF in skeletal muscle. Note that HIF-1α and VEGF were determined by using two-site immunoenzymatic assay (ELISA) methods. Our results demonstrated that hypoxic stress induced by exposure of lower O2 (6 h) significantly increased the levels of HIF-1α and VEGF in the oxidative and glycolytic muscles of SD rats and pikas (P<0.05 vs. normoxic conditions). Notably, the increases in HIF-1α and VEGF were significantly less in pikas (P<0.05, vs. SD controls) than in SD rats. In addition, a linear relationship was observed between amplified HIF-1α and VEGF in oxidative muscle (r=0.76 and P<0.01) and glycolytic muscle (r=0.72 and P<0.01) and inhibiting HIF-1α significantly decreased expression of VEGF induced by hypoxic stress in skeletal muscles (P<0.05). Overall, our findings suggest that (1) responsiveness of HIF-1α and VEGF in skeletal muscles to hypoxic stress is blunted in plateau animals, and (2) HIF-1α has a regulatory effect on VEGF under hypoxic environment.
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Affiliation(s)
| | | | | | - J.-G. LI
- College of Life Science, Shaanxi Normal University, Xi'an, China
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28
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The elusive importance of being a mitochondrial Ca2+ uniporter. Cell Calcium 2014; 55:139-45. [DOI: 10.1016/j.ceca.2014.02.008] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 02/07/2014] [Indexed: 12/20/2022]
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Clanton TL, Hogan MC, Gladden LB. Regulation of cellular gas exchange, oxygen sensing, and metabolic control. Compr Physiol 2013; 3:1135-90. [PMID: 23897683 DOI: 10.1002/cphy.c120030] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cells must continuously monitor and couple their metabolic requirements for ATP utilization with their ability to take up O2 for mitochondrial respiration. When O2 uptake and delivery move out of homeostasis, cells have elaborate and diverse sensing and response systems to compensate. In this review, we explore the biophysics of O2 and gas diffusion in the cell, how intracellular O2 is regulated, how intracellular O2 levels are sensed and how sensing systems impact mitochondrial respiration and shifts in metabolic pathways. Particular attention is paid to how O2 affects the redox state of the cell, as well as the NO, H2S, and CO concentrations. We also explore how these agents can affect various aspects of gas exchange and activate acute signaling pathways that promote survival. Two kinds of challenges to gas exchange are also discussed in detail: when insufficient O2 is available for respiration (hypoxia) and when metabolic requirements test the limits of gas exchange (exercising skeletal muscle). This review also focuses on responses to acute hypoxia in the context of the original "unifying theory of hypoxia tolerance" as expressed by Hochachka and colleagues. It includes discourse on the regulation of mitochondrial electron transport, metabolic suppression, shifts in metabolic pathways, and recruitment of cell survival pathways preventing collapse of membrane potential and nuclear apoptosis. Regarding exercise, the issues discussed relate to the O2 sensitivity of metabolic rate, O2 kinetics in exercise, and influences of available O2 on glycolysis and lactate production.
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Affiliation(s)
- T L Clanton
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA.
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Nicholson CK, Lambert JP, Chow CW, Lefer DJ, Calvert JW. Chronic exercise downregulates myocardial myoglobin and attenuates nitrite reductase capacity during ischemia-reperfusion. J Mol Cell Cardiol 2013; 64:1-10. [PMID: 23962643 PMCID: PMC3800246 DOI: 10.1016/j.yjmcc.2013.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 07/22/2013] [Accepted: 08/07/2013] [Indexed: 01/31/2023]
Abstract
The infarct sparing effects of exercise are evident following both long-term and short-term training regimens. Here we compared the infarct-lowering effects of nitrite therapy, voluntary exercise, and the combination of both following myocardial ischemia-reperfusion (MI/R) injury. We also compared the degree to which each strategy increased cardiac nitrite levels, as well as the effects of each strategy on the nitrite reductase activity of the heart. Mice subjected to voluntary wheel running (VE) for 4weeks displayed an 18% reduction in infarct size when compared to sedentary mice, whereas mice administered nitrite therapy (25mg/L in drinking water) showed a 53% decrease. However, the combination of VE and nitrite exhibited no further protection than VE alone. Although the VE and nitrite therapy mice showed similar nitrite levels in the heart, cardiac nitrite reductase activity was significantly reduced in the VE mice. Additionally, the cardiac protein expression of myoglobin, a known nitrite reductase, was also reduced after VE. Further studies revealed that cardiac NFAT activity was lower after VE due to a decrease in calcineurin activity and an increase in GSK3β activity. These data suggest that VE downregulates cardiac myoglobin levels by inhibiting calcineurin/NFAT signaling. Additionally, these results suggest that the modest infarct sparing effects of VE are the result of a decrease in the hearts ability to reduce nitrite to nitric oxide during MI/R.
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Affiliation(s)
- Chad K. Nicholson
- Department of Surgery, Division of Cardiothoracic Surgery, Carlyle Fraser Heart Center, Emory University School of Medicine, Atlanta, GA 30308
| | - Jonathan P. Lambert
- Department of Surgery, Division of Cardiothoracic Surgery, Carlyle Fraser Heart Center, Emory University School of Medicine, Atlanta, GA 30308
| | - Chi-Wing Chow
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - David J. Lefer
- Department of Surgery, Division of Cardiothoracic Surgery, Carlyle Fraser Heart Center, Emory University School of Medicine, Atlanta, GA 30308
| | - John W. Calvert
- Department of Surgery, Division of Cardiothoracic Surgery, Carlyle Fraser Heart Center, Emory University School of Medicine, Atlanta, GA 30308
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Abstract
Evolutionary forces drive beneficial adaptations in response to a complex array of environmental conditions. In contrast, over several millennia, humans have been so enamored by the running/athletic prowess of horses and dogs that they have sculpted their anatomy and physiology based solely upon running speed. Thus, through hundreds of generations, those structural and functional traits crucial for running fast have been optimized. Central among these traits is the capacity to uptake, transport and utilize oxygen at spectacular rates. Moreover, the coupling of the key systems--pulmonary-cardiovascular-muscular is so exquisitely tuned in horses and dogs that oxygen uptake response kinetics evidence little inertia as the animal transitions from rest to exercise. These fast oxygen uptake kinetics minimize Intramyocyte perturbations that can limit exercise tolerance. For the physiologist, study of horses and dogs allows investigation not only of a broader range of oxidative function than available in humans, but explores the very limits of mammalian biological adaptability. Specifically, the unparalleled equine cardiovascular and muscular systems can transport and utilize more oxygen than the lungs can supply. Two consequences of this situation, particularly in the horse, are profound exercise-induced arterial hypoxemia and hypercapnia as well as structural failure of the delicate blood-gas barrier causing pulmonary hemorrhage and, in the extreme, overt epistaxis. This chapter compares and contrasts horses and dogs with humans with respect to the structural and functional features that enable these extraordinary mammals to support their prodigious oxidative and therefore athletic capabilities.
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Affiliation(s)
- David C Poole
- Departments of Kinesiology, Anatomy and Physiology, Kansas State University, Manhattan, KS, USA.
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Clerte M, Baron DM, Brouckaert P, Ernande L, Raher MJ, Flynn AW, Picard MH, Bloch KD, Buys ES, Scherrer-Crosbie M. Brown adipose tissue blood flow and mass in obesity: a contrast ultrasound study in mice. J Am Soc Echocardiogr 2013; 26:1465-73. [PMID: 23993691 DOI: 10.1016/j.echo.2013.07.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Indexed: 12/31/2022]
Abstract
BACKGROUND When activated by the sympathetic nervous system, brown adipose tissue (BAT) increases energy expenditure to produce heat. Augmenting BAT mass or increasing BAT activation could potentially be used to decrease obesity. Noninvasive methods to detect and monitor BAT mass are needed. Contrast ultrasound can estimate BAT blood flow and is able to measure the perfused volume of an organ and thus its mass. The objective of this study was to evaluate whether contrast ultrasound could characterize BAT mass in two mouse models of obesity: wild-type mice fed a high-fat diet and mutant db/db mice. METHODS Contrast ultrasound of BAT (Definity 2 μL/min; 14-MHz linear probe) was performed before and after stimulation of BAT with norepinephrine (NE). BAT replenishment curves were obtained, and blood flow was estimated by the product of the curve's plateau and slope. Additionally, consecutive two-dimensional images of perfused BAT were acquired at 1-mm intervals after stimulation with NE and used to assess BAT volume and mass. RESULTS BAT blood flow increased after NE infusion in all mice studied. Blood flow response to NE was similar in wild-type mice fed either a low-fat diet or a high-fat diet. BAT blood flow was lower in db/db mice than in wild-type mice (P = .02). Contrast ultrasound-derived BAT mass was correlated with BAT mass obtained at necropsy (R(2) = 0.83, P < .001). BAT mass was higher in mice fed a high-fat diet than in those fed a low-fat diet. CONCLUSIONS Contrast ultrasound can be used to estimate BAT mass in mice when BAT vascularization is not significantly impaired. This noninvasive technique may potentially allow the serial evaluation of therapies designed to augment BAT mass.
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Affiliation(s)
- Maëva Clerte
- Cardiac Ultrasound Laboratory, Cardiology Division, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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Liu X, Xu J, Mei Q, Han L, Huang J. Myosin light chain kinase inhibitor inhibits dextran sulfate sodium-induced colitis in mice. Dig Dis Sci 2013; 58:107-14. [PMID: 22777616 DOI: 10.1007/s10620-012-2304-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Accepted: 06/25/2012] [Indexed: 12/24/2022]
Abstract
BACKGROUND AND AIMS Myosin light chain kinase (MLCK) plays a central role in the mechanisms of barrier dysfunction, and intestinal epithelial MLCK protein expression is upregulated in active ulcerative colitis (UC). ML-7, a MLCK inhibitor, has been used in many MLCK studies. However, the effect of ML-7 has never been estimated in colitis models. The aim of this study was to determine whether ML-7 can treat UC. METHODS Experimental colitis was induced and ML-7 was administered by intraperitoneal injection. The disease activity index (DAI) scores were evaluated and colon tissue was collected for the assessment of histological changes, myeloperoxidase (MPO) activity, and tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-13 and interleukin (IL)-17 levels. The small intestinal mucosa was ultrastructurally examined, epithelial MLCK protein expression and enzymatic activity were determined, and intestinal permeability was assayed using FITC-dextran 4000 (FD-4) and Evans blue (EB). RESULTS ML-7 was found to be significantly effective in reducing the DAI scores and histological index scores, and decreasing MPO activity and TNF-α, IFN-γ, IL-13 and IL-17 levels. The small intestinal epithelial MLCK protein expression and enzymatic activity were downregulated by ML-7. The epithelial cells and intercellular tight junctions were ameliorated, and the amount of FD-4 in blood and EB permeating into the intestine were decreased by ML-7 in colitis mice. CONCLUSIONS ML-7 has a significant anti-colitis effect in colitis mice. It is mainly associated with the inhibition of the epithelial MLCK protein expression, resulting in ameliorated intestinal mucosal permeability.
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Affiliation(s)
- Xiaochang Liu
- Department of Gastroenterology, First Affiliated Hospital of Anhui Medical University, The Key Laboratory of Digestive Diseases of Anhui Province, No. 218 Jixi Road, Hefei, Anhui, 230022, China
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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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Nitric oxide in myogenesis and therapeutic muscle repair. Mol Neurobiol 2012; 46:682-92. [PMID: 22821188 DOI: 10.1007/s12035-012-8311-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 07/12/2012] [Indexed: 12/20/2022]
Abstract
Nitric oxide is a short-lived intracellular and intercellular messenger. The first realisation that nitric oxide is important in physiology occurred in 1987 when its identity with the endothelium-derived relaxing factor was discovered. Subsequent studies have shown that nitric oxide possesses a number of physiological functions that are essential not only to vascular homeostasis but also to neurotransmission, such as in the processes of learning and memory and endocrine gland regulation, as well as inflammation and immune responses. The discovery in 1995 that a splice variant of the neuronal nitric oxide synthase is localised at the sarcolemma via the dystrophin-glycoprotein complex and of its displacement in Duchenne muscular dystrophy has stimulated a host of studies exploring the role of nitric oxide in skeletal muscle physiology. Recently, nitric oxide has emerged as a relevant messenger also of myogenesis that it regulates at several key steps, especially when the process is stimulated for muscle repair following acute and chronic muscle injuries. Here, we will review briefly the mechanisms and functions of nitric oxide in skeletal muscle and discuss its role in myogenesis, with specific attention to the promising nitric oxide-based approaches now being explored at the pre-clinical and clinical level for the therapy of muscular dystrophy.
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skNAC, a Smyd1-interacting transcription factor, is involved in cardiac development and skeletal muscle growth and regeneration. Proc Natl Acad Sci U S A 2010; 107:20750-5. [PMID: 21071677 DOI: 10.1073/pnas.1013493107] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cardiac and skeletal muscle development and maintenance require complex interactions between DNA-binding proteins and chromatin remodeling factors. We previously reported that Smyd1, a muscle-restricted histone methyltransferase, is essential for cardiogenesis and functions with a network of cardiac regulatory proteins. Here we show that the muscle-specific transcription factor skNAC is the major binding partner for Smyd1 in the developing heart. Targeted deletion of skNAC in mice resulted in partial embryonic lethality by embryonic day 12.5, with ventricular hypoplasia and decreased cardiomyocyte proliferation that were similar but less severe than in Smyd1 mutants. Expression of Irx4, a ventricle-specific transcription factor down-regulated in hearts lacking Smyd1, also depended on the presence of skNAC. Viable skNAC(-/-) adult mice had reduced postnatal skeletal muscle growth and impaired regenerative capacity after cardiotoxin-induced injury. Satellite cells isolated from skNAC(-/-) mice had impaired survival compared with wild-type littermate satellite cells. Our results indicate that skNAC plays a critical role in ventricular cardiomyocyte expansion and regulates postnatal skeletal muscle growth and regeneration in mice.
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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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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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Probst-Cousin S, Neundörfer B, Heuss D. Microvasculopathic neuromuscular diseases: Lessons from hypoxia-inducible factors. Neuromuscul Disord 2010; 20:192-7. [DOI: 10.1016/j.nmd.2010.01.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2009] [Revised: 12/21/2009] [Accepted: 01/07/2010] [Indexed: 10/19/2022]
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Abstract
Neuromuscular diseases can affect the survival of peripheral neurons, their axons extending to peripheral targets, their synaptic connections onto those targets, or the targets themselves. Examples include motor neuron diseases such as amyotrophic lateral sclerosis, peripheral neuropathies, such as Charcot-Marie-Tooth diseases, myasthenias, and muscular dystrophies. Characterizing these phenotypes in mouse models requires an integrated approach, examining both the nerve and the muscle histologically, anatomically, and functionally by electrophysiology. Defects observed at these levels can be related back to onset, severity, and progression, as assessed by "quality-of-life measures" including tests of gross motor performance such as gait or grip strength. This chapter describes methods for assessing neuromuscular disease models in mice, and how interpretation of these tests can be complicated by the inter-relatedness of the phenotypes.
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Esteva S, Panisello P, Ramon Torrella J, Pagés T, Viscor G. Enzyme activity and myoglobin concentration in rat myocardium and skeletal muscles after passive intermittent simulated altitude exposure. J Sports Sci 2009; 27:633-40. [DOI: 10.1080/02640410802713480] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Wittenberg BA. Both hypoxia and work are required to enhance expression of myoglobin in skeletal muscle. Focus on “Hypoxia reprograms calcium signaling and regulates myoglobin expression”. Am J Physiol Cell Physiol 2009; 296:C390-2. [DOI: 10.1152/ajpcell.00002.2009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Ramanathan R, Konda M, Mancini R, Faustman C. Species-Specific Effects of Sarcoplasmic Extracts on Lipid Oxidationin vitro. J Food Sci 2009; 74:C73-7. [DOI: 10.1111/j.1750-3841.2008.01021.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kanatous SB, Mammen PPA, Rosenberg PB, Martin CM, White MD, Dimaio JM, Huang G, Muallem S, Garry DJ. Hypoxia reprograms calcium signaling and regulates myoglobin expression. Am J Physiol Cell Physiol 2008; 296:C393-402. [PMID: 19005161 DOI: 10.1152/ajpcell.00428.2008] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myoglobin is an oxygen storage molecule that is selectively expressed in cardiac and slow-twitch skeletal muscles that have a high oxygen demand. Numerous studies have implicated hypoxia in the regulation of myoglobin expression as an adaptive response to hypoxic stress. However, the details of this relationship remain undefined. In the present study, adult mice exposed to 10% oxygen for periods up to 3 wk exhibited increased myoglobin expression only in the working heart, whereas myoglobin was either diminished or unchanged in skeletal muscle groups. In vitro and in vivo studies revealed that hypoxia in the presence or absence of exercise-induced stimuli reprograms calcium signaling and modulates myoglobin gene expression. Hypoxia alone significantly altered calcium influx in response to cell depolarization or depletion of endoplasmic reticulum calcium stores, which inhibited the expression of myoglobin. In contrast, our whole animal and transcriptional studies indicate that hypoxia in combination with exercise enhanced the release of calcium from the sarcoplasmic reticulum via the ryanodine receptors triggered by caffeine, which increased the translocation of nuclear factor of activated T-cells into the nucleus to transcriptionally activate myoglobin expression. The present study unveils a previously unrecognized mechanism where the hypoxia-mediated regulation of calcium transients from different intracellular pools modulates myoglobin gene expression. In addition, we observed that changes in myoglobin expression, in response to hypoxia, are not dependent on hypoxia-inducible factor-1 or changes in skeletal muscle fiber type. These studies enhance our understanding of hypoxia-mediated gene regulation and will have broad applications for the treatment of myopathic diseases.
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Affiliation(s)
- Shane B Kanatous
- Department of Biology, Colorado State University, Fort Collins, CO, USA
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Feighery LM, Cochrane SW, Quinn T, Baird AW, O'Toole D, Owens SE, O'Donoghue D, Mrsny RJ, Brayden DJ. Myosin light chain kinase inhibition: correction of increased intestinal epithelial permeability in vitro. Pharm Res 2008; 25:1377-86. [PMID: 18163202 DOI: 10.1007/s11095-007-9527-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Accepted: 12/10/2007] [Indexed: 01/12/2023]
Abstract
PURPOSE To examine whether myosin light chain kinase (MLCK) inhibitors can reduce intestinal epithelial permeability increases in vitro. MATERIALS AND METHODS Isolated rat, mouse and human colonic tissue mucosae and Caco-2 monolayers were exposed to cytochalasin D (cD) and sodium caprate (C10), in the absence and presence of the MLCK inhibitors, ML-9 and D PIK. Transepithelial electrical resistance (TEER) and Papp of [14C]-mannitol or FITC-dextran 4000 (FD-4) were measured. Western blots were used to measure MLC phosphorylation. RESULTS Increases in Papp of [14C]-mannitol and decreases in TEER were induced by tight junction openers. These changes were attenuated by ML-9. D-PIK offset the FD-4 Papp increase induced by C10 in Caco-2 only, while ML-9 and PIK inhibited MLC directly, cD induced constriction of peri-junctional actin in Caco-2 monolayers, but this was prevented by ML-9. Although mannitol fluxes across colonic mucosae from dextran-sulphate (DSS)-treated mice were higher than control, they were not ameliorated by either ML-9 or PIK in vitro. CONCLUSIONS ML-9 inhibits paracellular permeability increases in several intestinal epithelial models. D-PIK reduced stimulated paracellular fluxes in Caco-2 monolayers, but not in tissue. Pre-established increases were not modified by two MLCK inhibitors in a mouse model of IBD.
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Affiliation(s)
- Linda M Feighery
- School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
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Mänttäri S, Anttila K, Järvilehto M. Testosterone stimulates myoglobin expression in different muscles of the mouse. J Comp Physiol B 2008; 178:899-907. [PMID: 18548256 DOI: 10.1007/s00360-008-0280-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Revised: 05/16/2008] [Accepted: 05/25/2008] [Indexed: 10/22/2022]
Abstract
The regulation of energy metabolism is one of the major functions of steroid hormones. This study was performed to explore whether testosterone can regulate the aerobic capacity of skeletal muscles via myoglobin expression. To study this, changes in testosterone level were quantified, and the level of myoglobin protein was analyzed using Western blot in mice subjected to 6 weeks of training (T) or testosterone administration (A). Both treatments significantly increased the plasma testosterone level when compared to the untrained (U) or control (C) group. Training induced a significant increase in the myoglobin content in gastrocnemius and plantaris muscles (287 and 83%, respectively). Testosterone administration increased myoglobin concentration in plantaris (183%) but not in gastrocnemius. In extensor digitorum longus muscle the protein content decreased slightly after exercise, but increased 78% after testosterone administration. In soleus and rectus femoris muscles the myoglobin content was unchanged after both treatments. The data show that testosterone and training have differential effects on the concentration of myoglobin in some, but not all muscles. This may have an influence on the aerobic capacity in mouse skeletal muscles. The data demonstrated that both testosterone administration and training induced an increase in plasma testosterone level. However, the effects of the treatments on the myoglobin concentration differ.
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Affiliation(s)
- Satu Mänttäri
- Department of Biology, University of Oulu, 90014 Oulu, Finland.
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Patel S, Singh K, Singh S, Singh MP. Gene expression profiles of mouse striatum in control and maneb + paraquat-induced Parkinson's disease phenotype: validation of differentially expressed energy metabolizing transcripts. Mol Biotechnol 2008; 40:59-68. [PMID: 18386188 DOI: 10.1007/s12033-008-9060-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2008] [Accepted: 03/04/2008] [Indexed: 11/28/2022]
Abstract
The present study was undertaken to investigate the gene expression patterns of the striatum of control and maneb + paraquat-induced Parkinson's disease (PD) phenotype in mouse to identify the differentially expressed transcripts. The animals were treated with and without maneb (30 mg/kg, i.p.) + paraquat (10 mg/kg, i.p.), twice a week, for 3, 6, and 9 weeks. The RNA was isolated from control and treated mouse striatum and reverse transcribed, and equal quantities of labeled cDNA were mixed and hybridized with mouse 15 k arrays. Comparative transcription patterns showed the time of exposure dependent alteration in the expression of several transcripts associated with various pathways. RT-PCR reconfirmed the differential expression of some energy metabolizing transcripts. The study provides maneb + paraquat-induced differential expression of many transcripts using high-density microarray approach. Few transcripts, which were previously not reported to be associated with neuronal degeneration, were also identified. The results obtained thus suggest that maneb + paraquat induce neurotoxicity in the striatum in a time of exposure dependent manner via multiple pathways and defective energy metabolism could play a critical role.
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Affiliation(s)
- Suman Patel
- Industrial Toxicology Research Centre , Mahatma Gandhi Marg, Lucknow, 226 001, India
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48
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Kawada S, Ishii N. Changes in skeletal muscle size, fibre-type composition and capillary supply after chronic venous occlusion in rats. Acta Physiol (Oxf) 2008; 192:541-9. [PMID: 17970825 DOI: 10.1111/j.1748-1716.2007.01761.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIM We have previously shown that surgical occlusion of some veins from skeletal muscle results in muscle hypertrophy without mechanical overloading in the rat. The present study investigated the changes in muscle-fibre composition and capillary supply in hypertrophied muscles after venous occlusion in the rat hindlimb. METHODS Sixteen male Wistar rats were randomly assigned into two groups: (i) sham operated (sham-operated group; n = 7); (ii) venous occluded for 2 weeks (2-week-occluded group; n = 9). At the end of the experimental period, specimens of the plantaris muscle were dissected from the hindlimbs and subjected to biochemical and histochemical analyses. RESULTS Two weeks after the occlusion, both the wet weight of plantaris muscle relative to body weight and absolute muscle weight showed significant increases in the 2-week-occluded group ( approximately 15%) when compared with those in the sham-operated group. The concentrations of muscle glycogen and lactate were higher in the 2-week-occluded group, whereas staining intensity of muscle lipid droplets was lower in the 2-week-occluded group than those in the sham-operated group. The percentage of type I muscle fibre decreased, whereas that of type IIb fibre increased in the 2-week-occluded group when compared with the sham-operated group. Although the expression of vascular endothelial growth factor-188 mRNA increased, the number of capillaries around the muscle fibres tended to decrease (P = 0.07). CONCLUSION Chronic venous occlusion causes skeletal muscle hypertrophy with fibre-type transition towards faster types and changes in contents of muscle metabolites.
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Affiliation(s)
- S Kawada
- Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Chiba Prefecture, Japan.
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49
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Protein kinase D1 stimulates MEF2 activity in skeletal muscle and enhances muscle performance. Mol Cell Biol 2008; 28:3600-9. [PMID: 18378694 DOI: 10.1128/mcb.00189-08] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Skeletal muscle consists of type I and type II myofibers, which exhibit different metabolic and contractile properties. Type I fibers display an oxidative metabolism and are resistant to fatigue, whereas type II fibers are primarily glycolytic and suited for rapid bursts of activity. These properties can be modified by changes in workload, activity, and hormonal stimuli, facilitating muscle adaptation to physiological demand. The MEF2 transcription factor promotes the formation of slow-twitch (type I) muscle fibers in response to activity. MEF2 activity is repressed by class II histone deacetylases (HDACs) and is enhanced by calcium-regulated protein kinases that promote the export of class II HDACs from the nucleus to the cytoplasm. However, the identities of skeletal muscle class II HDAC kinases are not well defined. Here we demonstrate that protein kinase D1 (PKD1), a highly effective class II HDAC kinase, is predominantly expressed in type I myofibers and, when misexpressed in type II myofibers, promotes transformation to a type I, slow-twitch, fatigue-resistant phenotype. Conversely, genetic deletion of PKD1 in type I myofibers increases susceptibility to fatigue. PKD1 cooperates with calcineurin to facilitate slow-twitch-fiber transformation. These findings identify PKD1 as a key regulator of skeletal muscle function and phenotype.
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50
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Meeson AP, Shi X, Alexander MS, Williams RS, Allen RE, Jiang N, Adham IM, Goetsch SC, Hammer RE, Garry DJ. Sox15 and Fhl3 transcriptionally coactivate Foxk1 and regulate myogenic progenitor cells. EMBO J 2007; 26:1902-12. [PMID: 17363903 PMCID: PMC1847663 DOI: 10.1038/sj.emboj.7601635] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Accepted: 02/07/2007] [Indexed: 01/12/2023] Open
Abstract
The regulation of myogenic progenitor cells during muscle regeneration is not clearly understood. We have previously shown that the Foxk1 gene, a member of the forkhead/winged helix family of transcription factors, is expressed in myogenic progenitor cells in adult skeletal muscle. In the present study, we utilize transgenic technology and demonstrate that the 4.6 kb upstream fragment of the Foxk1 gene directs beta-galactosidase expression to the myogenic progenitor cell population. We further establish that Sox15 directs Foxk1 expression to the myogenic progenitor cell population, as it binds to an evolutionarily conserved site and recruits Fhl3 to transcriptionally coactivate Foxk1 gene expression. Knockdown of endogenous Sox15 results in perturbed cell cycle kinetics and decreased Foxk1 expression. Furthermore, Sox15 mutant mice display perturbed skeletal muscle regeneration, due in part to decreased numbers of satellite cells and decreased Foxk1 expression. These studies demonstrate that Sox15, Fhl3 and Foxk1 function to coordinately regulate the myogenic progenitor cell population and skeletal muscle regeneration.
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Affiliation(s)
- Annette P Meeson
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaozhong Shi
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Matthew S Alexander
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - R S Williams
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Ronald E Allen
- Department of Animal Sciences, University of Arizona, Tucson, AZ, USA
| | - Nan Jiang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ibrahim M Adham
- Institute of Human Genetics, University of Göttingen, Göttingen, Germany
| | - Sean C Goetsch
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Robert E Hammer
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Daniel J Garry
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Donald W Reynolds Cardiovascular Clinical Research Center at UT Southwestern Medical Center, Dallas, TX, USA
- Internal Medicine-Cardiology, NB11.118A, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8573, USA. Tel.: +1 214 648 1654; Fax: +1 214 648 1450; E-mail:
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