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Upanan S, Lee J, Tunau-Spencer KJ, Rajvanshi PK, Wright EC, Noguchi CT, Schechter AN. High nitrate levels in skeletal muscle contribute to nitric oxide generation via a nitrate/nitrite reductive pathway in mice that lack the nNOS enzyme. Front Physiol 2024; 15:1352242. [PMID: 38784116 PMCID: PMC11112080 DOI: 10.3389/fphys.2024.1352242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 04/05/2024] [Indexed: 05/25/2024] Open
Abstract
Introduction Nitric oxide (NO) is a vasodilator gas that plays a critical role in mitochondrial respiration and skeletal muscle function. NO is endogenously generated by NO synthases: neuronal NO synthase (nNOS), endothelial NO synthase (eNOS), or inducible NO synthase (iNOS). NO in skeletal muscle is partly generated by nNOS, and nNOS deficiency can contribute to muscular dystrophic diseases. However, we and others discovered an alternative nitrate/nitrite reductive pathway for NO generation: nitrate to nitrite to NO. We hypothesized that nitrate supplementation would increase nitrate accumulation in skeletal muscle and promote a nitrate/nitrite reductive pathway for NO production to compensate for the loss of nNOS in skeletal muscle. Methods Wild-type (WT) and genetic nNOS knockout (nNOS-/-) mice were fed normal chow (386.9 nmol/g nitrate) and subjected to three treatments: high-nitrate water (1 g/L sodium nitrate for 7 days), low-nitrate diet (46.8 nmol/g nitrate for 7 days), and low-nitrate diet followed by high-nitrate water for 7 days each. Results High-nitrate water supplementation exhibited a greater and more significant increase in nitrate levels in skeletal muscle and blood in nNOS-/- mice than in WT mice. A low-nitrate diet decreased blood nitrate and nitrite levels in both WT and nNOS-/- mice. WT and nNOS-/- mice, treated with low-nitrate diet, followed by high-nitrate water supplementation, showed a significant increase in nitrate levels in skeletal muscle and blood, analogous to the increases observed in nNOS-/- mice supplemented with high-nitrate water. In skeletal muscle of nNOS-/- mice on high-nitrate water supplementation, on low-nitrate diet, and in low-high nitrate treatment, the loss of nNOS resulted in a corresponding increase in the expression of nitrate/nitrite reductive pathway-associated nitrate transporters [sialin and chloride channel 1 (CLC1)] and nitrate/nitrite reductase [xanthine oxidoreductase (XOR)] but did not show a compensatory increase in iNOS or eNOS protein and eNOS activation activity [p-eNOS (Ser1177)]. Discussion These findings suggest that a greater increase in nitrate levels in skeletal muscle of nNOS-/- mice on nitrate supplementation results from reductive processes to increase NO production with the loss of nNOS in skeletal muscle.
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Affiliation(s)
- Supranee Upanan
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Jeeyoung Lee
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Khalid J. Tunau-Spencer
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Praveen K. Rajvanshi
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Elizabeth C. Wright
- Office of the Director, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Constance T. Noguchi
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Alan N. Schechter
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
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Baum O. Expression of neuronal NO synthase α- and β-isoforms in skeletal muscle of mice. Biochem J 2024; 481:601-613. [PMID: 38592741 DOI: 10.1042/bcj20230458] [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: 11/02/2023] [Revised: 03/27/2024] [Accepted: 04/09/2024] [Indexed: 04/10/2024]
Abstract
Knowledge of the primary structure of neuronal NO synthase (nNOS) in skeletal muscle is still conflicting and needs further clarification. To elucidate the expression patterns of nNOS isoforms at both mRNA and protein level, systematic reverse transcription (RT)-PCR and epitope mapping by qualitative immunoblot analysis on skeletal muscle of C57/BL6 mice were performed. The ability of the nNOS isoforms to form aggregates was characterized by native low-temperature polyacrylamide electrophoresis (LT-PAGE). The molecular analysis was focused on the rectus femoris (RF) muscle, a skeletal muscle with a nearly balanced ratio of nNOS α- and β-isoforms. RT-PCR amplificates from RF muscles showed exclusive exon-1d mRNA expression, either with or without exon-μ. Epitope mapping demonstrated the simultaneous expression of the nNOS splice variants α/μ, α/non-μ, β/μ and β/non-μ. Furthermore, immunoblotting suggests that the transition between nNOS α- and β-isoforms lies within exon-3. In LT-PAGE, three protein nNOS associated aggregates were detected in homogenates of RF muscle and tibialis anterior muscle: a 320 kDa band containing nNOS α-isoforms, while 250 and 300 kDa bands consist of nNOS β-isoforms that form homodimers or heterodimers with non-nNOS proteins.
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Affiliation(s)
- Oliver Baum
- Institute of Physiology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
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Baum O, Huber-Abel FAM, Flück M. nNOS Increases Fiber Type-Specific Angiogenesis in Skeletal Muscle of Mice in Response to Endurance Exercise. Int J Mol Sci 2023; 24:ijms24119341. [PMID: 37298293 DOI: 10.3390/ijms24119341] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 05/23/2023] [Accepted: 05/23/2023] [Indexed: 06/12/2023] Open
Abstract
We studied the relationship between neuronal NO synthase (nNOS) expression and capillarity in the tibialis anterior (TA) muscle of mice subjected to treadmill training. The mRNA (+131%) and protein (+63%) levels of nNOS were higher (p ≤ 0.05) in the TA muscle of C57BL/6 mice undergoing treadmill training for 28 days than in those of littermates remaining sedentary, indicating an up-regulation of nNOS by endurance exercise. Both TA muscles of 16 C57BL/6 mice were subjected to gene electroporation with either the pIRES2-ZsGreen1 plasmid (control plasmid) or the pIRES2-ZsGreen1-nNOS gene-inserted plasmid (nNOS plasmid). Subsequently, one group of mice (n = 8) underwent treadmill training for seven days, while the second group of mice (n = 8) remained sedentary. At study end, 12-18% of TA muscle fibers expressed the fluorescent reporter gene ZsGreen1. Immunofluorescence for nNOS was 23% higher (p ≤ 0.05) in ZsGreen1-positive fibers than ZsGreen1-negative fibers from the nNOS-transfected TA muscle of mice subjected to treadmill training. Capillary contacts around myosin heavy-chain (MHC)-IIb immunoreactive fibers (14.2%; p ≤ 0.05) were only higher in ZsGreen1-positive fibers than ZsGreen1-negative fibers in the nNOS-plasmid-transfected TA muscles of trained mice. Our observations are in line with an angiogenic effect of quantitative increases in nNOS expression, specifically in type-IIb muscle fibers after treadmill training.
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Affiliation(s)
- Oliver Baum
- Institute of Physiology, Charité-Universitätsmedizin, 10117 Berlin, Germany
| | | | - Martin Flück
- Heart Repair and Regeneration Laboratory, Department EMC, Faculty of Science and Medicine, University of Fribourg, 1700 Fribourg, Switzerland
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Cáceres-Ayala C, Mira RG, Acuña MJ, Brandan E, Cerpa W, Rebolledo DL. Episodic Binge-like Ethanol Reduces Skeletal Muscle Strength Associated with Atrophy, Fibrosis, and Inflammation in Young Rats. Int J Mol Sci 2023; 24:ijms24021655. [PMID: 36675170 PMCID: PMC9861047 DOI: 10.3390/ijms24021655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 01/18/2023] Open
Abstract
Binge Drinking (BD) corresponds to episodes of ingestion of large amounts of ethanol in a short time, typically ≤2 h. BD occurs across all populations, but young and sports-related people are especially vulnerable. However, the short- and long-term effects of episodic BD on skeletal muscle function have been poorly explored. Young rats were randomized into two groups: control and episodic Binge-Like ethanol protocol (BEP) (ethanol 3 g/kg IP, 4 episodes of 2-days ON-2-days OFF paradigm). Muscle function was evaluated two weeks after the last BEP episode. We found that rats exposed to BEP presented decreased muscle strength and increased fatigability, compared with control animals. Furthermore, we observed that skeletal muscle from rats exposed to BEP presented muscle atrophy, evidenced by reduced fiber size and increased expression of atrophic genes. We also observed that BEP induced fibrotic and inflammation markers, accompanied by mislocalization of nNOSµ and high levels of protein nitration. Our findings suggest that episodic binge-like ethanol exposure alters contractile capacity and increases fatigue by mechanisms involving atrophy, fibrosis, and inflammation, which remain for at least two weeks after ethanol clearance. These pathological features are common to several neuromuscular diseases and might affect muscle performance and health in the long term.
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Affiliation(s)
- Constanza Cáceres-Ayala
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas 6213515, Chile
- Laboratorio de Función y Patología Neuronal, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Rodrigo G. Mira
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas 6213515, Chile
- Laboratorio de Función y Patología Neuronal, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - María José Acuña
- Centro Integrativo de Biología y Química Aplicada (CIBQA), Universidad Bernardo O’Higgins, Santiago 8370854, Chile
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago 7780272, Chile
| | - Enrique Brandan
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago 7780272, Chile
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago 7510157, Chile
- Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Waldo Cerpa
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas 6213515, Chile
- Laboratorio de Función y Patología Neuronal, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
- Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
- Correspondence: (W.C.); (D.L.R.)
| | - Daniela L. Rebolledo
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas 6213515, Chile
- Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
- Correspondence: (W.C.); (D.L.R.)
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Nassoro DD, Torres L, Marando R, Mboma L, Mushi S, Habakkuk Mwakyula I. A child with duchenne muscular dystrophy: A case report of a rare diagnosis among Africans. Clin Case Rep 2020; 8:2654-2660. [PMID: 33363799 PMCID: PMC7752564 DOI: 10.1002/ccr3.3254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 07/20/2020] [Accepted: 07/22/2020] [Indexed: 01/14/2023] Open
Abstract
In Africa, lack of awareness and low index of suspicion of rare diseases like dystrophinopathies, directly or indirectly, contributes to the increased morbidity and mortality. Therefore, even though the data on prevalence is limited, we need to have a high degree of suspicion in patients presenting with suggestive clinical features.
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Affiliation(s)
- David D. Nassoro
- Department of Internal MedicineMbeya Zonal Referral HospitalMbeyaTanzania
- Department of Internal MedicineThe University of Dar es SalaamMbeya College of Health and Allied SciencesMbeyaTanzania
| | - Liset Torres
- Department of PathologyMbeya Zonal Referral HospitalMbeyaTanzania
- Department of PathologyThe University of Dar es SalaamMbeya College of Health and Allied SciencesMbeyaTanzania
| | - Rehema Marando
- Department of Pediatrics and Child HealthMbeya Zonal Referral HospitalMbeyaTanzania
- Department of Pediatrics and Child HealthThe University of Dar es SalaamMbeya College of Health and Allied SciencesMbeyaTanzania
| | - Lazaro Mboma
- Department of SurgeryMbeya Zonal Referral HospitalMbeyaTanzania
- Department of SurgeryThe University of Dar es SalaamMbeya College of Health and Allied SciencesMbeyaTanzania
| | - Seraphine Mushi
- Department of PhysiotherapyMbeya Zonal Referral HospitalMbeyaTanzania
| | - Issakwisa Habakkuk Mwakyula
- Department of Internal MedicineMbeya Zonal Referral HospitalMbeyaTanzania
- Department of Internal MedicineThe University of Dar es SalaamMbeya College of Health and Allied SciencesMbeyaTanzania
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Meng J, Counsell J, Morgan JE. Effects of Mini-Dystrophin on Dystrophin-Deficient, Human Skeletal Muscle-Derived Cells. Int J Mol Sci 2020; 21:E7168. [PMID: 32998454 PMCID: PMC7582244 DOI: 10.3390/ijms21197168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 09/22/2020] [Accepted: 09/24/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND We are developing a novel therapy for Duchenne muscular dystrophy (DMD), involving the transplantation of autologous, skeletal muscle-derived stem cells that have been genetically corrected to express dystrophin. Dystrophin is normally expressed in activated satellite cells and in differentiated muscle fibres. However, in past preclinical validation studies, dystrophin transgenes have generally been driven by constitutive promoters that would be active at every stage of the myogenic differentiation process, including in proliferating muscle stem cells. It is not known whether artificial dystrophin expression would affect the properties of these cells. AIMS Our aims are to determine if mini-dystrophin expression affects the proliferation or myogenic differentiation of DMD skeletal muscle-derived cells. METHODS Skeletal muscle-derived cells from a DMD patient were transduced with lentivirus coding for mini-dystrophins (R3-R13 spectrin-like repeats (ΔR3R13) or hinge2 to spectrin-like repeats R23 (ΔH2R23)) with EGFP (enhanced green fluorescence protein) fused to the C-terminus, driven by a constitutive promoter, spleen focus-forming virus (SFFV). Transduced cells were purified on the basis of GFP expression. Their proliferation and myogenic differentiation were quantified by ethynyl deoxyuridine (EdU) incorporation and fusion index. Furthermore, dystrophin small interfering ribonucleic acids (siRNAs) were transfected to the cells to reverse the effects of the mini-dystrophin. Finally, a phospho-mitogen-activated protein kinase (MAPK) array assay was performed to investigate signalling pathway changes caused by dystrophin expression. RESULTS Cell proliferation was not affected in cells transduced with ΔR3R13, but was significantly increased in cells transduced with ΔH2R23. The fusion index of myotubes derived from both ΔR3R13- and ΔH2R23 -expressing cells was significantly compromised in comparison to myotubes derived from non-transduced cells. Dystrophin siRNA transfection restored the differentiation of ΔH2R23-expressing cells. The Erk1/2- signalling pathway is altered in cells transduced with mini-dystrophin constructs. CONCLUSIONS Ectopic expression of dystrophin in cultured human skeletal muscle-derived cells may affect their proliferation and differentiation capacity. Caution should be taken when considering genetic correction of autologous stem cells to express dystrophin driven by a constitutive promoter.
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MESH Headings
- Cell Differentiation
- Cell Engineering/methods
- Cell Proliferation
- Dystrophin/antagonists & inhibitors
- Dystrophin/genetics
- Dystrophin/metabolism
- Gene Expression Regulation
- Genes, Reporter
- Genetic Vectors/chemistry
- Genetic Vectors/metabolism
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Humans
- Lentivirus/genetics
- Lentivirus/metabolism
- MAP Kinase Signaling System
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/metabolism
- Muscular Dystrophy, Duchenne/pathology
- Plasmids/chemistry
- Plasmids/metabolism
- Primary Cell Culture
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Spectrin/genetics
- Spectrin/metabolism
- Transduction, Genetic
- Transgenes
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Affiliation(s)
- Jinhong Meng
- Dubowitz Neuromuscular Centre, Developmental Neuroscience Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK; (J.M.); (J.C.)
- NIHR Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health & Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 1EH, UK
| | - John Counsell
- Dubowitz Neuromuscular Centre, Developmental Neuroscience Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK; (J.M.); (J.C.)
- NIHR Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health & Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 1EH, UK
| | - Jennifer E. Morgan
- Dubowitz Neuromuscular Centre, Developmental Neuroscience Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK; (J.M.); (J.C.)
- NIHR Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health & Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 1EH, UK
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Mukund K, Subramaniam S. Skeletal muscle: A review of molecular structure and function, in health and disease. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2020; 12:e1462. [PMID: 31407867 PMCID: PMC6916202 DOI: 10.1002/wsbm.1462] [Citation(s) in RCA: 208] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 07/03/2019] [Accepted: 07/03/2019] [Indexed: 12/11/2022]
Abstract
Decades of research in skeletal muscle physiology have provided multiscale insights into the structural and functional complexity of this important anatomical tissue, designed to accomplish the task of generating contraction, force and movement. Skeletal muscle can be viewed as a biomechanical device with various interacting components including the autonomic nerves for impulse transmission, vasculature for efficient oxygenation, and embedded regulatory and metabolic machinery for maintaining cellular homeostasis. The "omics" revolution has propelled a new era in muscle research, allowing us to discern minute details of molecular cross-talk required for effective coordination between the myriad interacting components for efficient muscle function. The objective of this review is to provide a systems-level, comprehensive mapping the molecular mechanisms underlying skeletal muscle structure and function, in health and disease. We begin this review with a focus on molecular mechanisms underlying muscle tissue development (myogenesis), with an emphasis on satellite cells and muscle regeneration. We next review the molecular structure and mechanisms underlying the many structural components of the muscle: neuromuscular junction, sarcomere, cytoskeleton, extracellular matrix, and vasculature surrounding muscle. We highlight aberrant molecular mechanisms and their possible clinical or pathophysiological relevance. We particularly emphasize the impact of environmental stressors (inflammation and oxidative stress) in contributing to muscle pathophysiology including atrophy, hypertrophy, and fibrosis. This article is categorized under: Physiology > Mammalian Physiology in Health and Disease Developmental Biology > Developmental Processes in Health and Disease Models of Systems Properties and Processes > Cellular Models.
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Affiliation(s)
- Kavitha Mukund
- Department of BioengineeringUniversity of CaliforniaSan DiegoCalifornia
| | - Shankar Subramaniam
- Department of Bioengineering, Bioinformatics & Systems BiologyUniversity of CaliforniaSan DiegoCalifornia
- Department of Computer Science and EngineeringUniversity of CaliforniaSan DiegoCalifornia
- Department of Cellular and Molecular Medicine and NanoengineeringUniversity of CaliforniaSan DiegoCalifornia
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Zhao J, Yang HT, Wasala L, Zhang K, Yue Y, Duan D, Lai Y. Dystrophin R16/17 protein therapy restores sarcolemmal nNOS in trans and improves muscle perfusion and function. Mol Med 2019; 25:31. [PMID: 31266455 PMCID: PMC6607532 DOI: 10.1186/s10020-019-0101-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 06/20/2019] [Indexed: 01/08/2023] Open
Abstract
Background Delocalization of neuronal nitric oxide synthase (nNOS) from the sarcolemma leads to functional muscle ischemia. This contributes to the pathogenesis in cachexia, aging and muscular dystrophy. Mutations in the gene encoding dystrophin result in Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). In many BMD patients and DMD patients that have been converted to BMD by gene therapy, sarcolemmal nNOS is missing due to the lack of dystrophin nNOS-binding domain. Methods Dystrophin spectrin-like repeats 16 and 17 (R16/17) is the sarcolemmal nNOS localization domain. Here we explored whether R16/17 protein therapy can restore nNOS to the sarcolemma and prevent functional ischemia in transgenic mice which expressed an R16/17-deleted human micro-dystrophin gene in the dystrophic muscle. The palmitoylated R16/17.GFP fusion protein was conjugated to various cell-penetrating peptides and produced in the baculovirus-insect cell system. The best fusion protein was delivered to the transgenic mice and functional muscle ischemia was quantified. Results Among five candidate cell-penetrating peptides, the mutant HIV trans-acting activator of transcription (TAT) protein transduction domain (mTAT) was the best in transferring the R16/17.GFP protein to the muscle. Systemic delivery of the mTAT.R16/17.GFP protein to micro-dystrophin transgenic mice successfully restored sarcolemmal nNOS without inducing T cell infiltration. More importantly, R16/17 protein therapy effectively prevented treadmill challenge-induced force loss and improved muscle perfusion during contraction. Conclusions Our results suggest that R16/17 protein delivery is a highly promising therapy for muscle diseases involving sarcolemmal nNOS delocalizaton. Electronic supplementary material The online version of this article (10.1186/s10020-019-0101-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Junling Zhao
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Medical Sciences Building, One Hospital Drive, Columbia, MO, 65212, USA
| | - Hsiao Tung Yang
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65212, USA
| | - Lakmini Wasala
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Medical Sciences Building, One Hospital Drive, Columbia, MO, 65212, USA
| | - Keqing Zhang
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Medical Sciences Building, One Hospital Drive, Columbia, MO, 65212, USA
| | - Yongping Yue
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Medical Sciences Building, One Hospital Drive, Columbia, MO, 65212, USA
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Medical Sciences Building, One Hospital Drive, Columbia, MO, 65212, USA. .,Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65212, USA. .,Department of Neurology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA. .,Department of Bioengineering, University of Missouri, Columbia, MO, 65212, USA.
| | - Yi Lai
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Medical Sciences Building, One Hospital Drive, Columbia, MO, 65212, USA.
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9
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Balke JE, Zhang L, Percival JM. Neuronal nitric oxide synthase (nNOS) splice variant function: Insights into nitric oxide signaling from skeletal muscle. Nitric Oxide 2018; 82:35-47. [PMID: 30503614 DOI: 10.1016/j.niox.2018.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 11/19/2018] [Accepted: 11/20/2018] [Indexed: 02/07/2023]
Abstract
Defects in neuronal nitric oxide synthase (nNOS) splice variant localization and signaling in skeletal muscle are a firmly established pathogenic characteristic of many neuromuscular diseases, including Duchenne and Becker muscular dystrophy (DMD and BMD, respectively). Therefore, substantial efforts have been made to understand and therapeutically target skeletal muscle nNOS isoform signaling. The purpose of this review is to summarize recent salient advances in understanding of the regulation, targeting, and function of nNOSμ and nNOSβ splice variants in normal and dystrophic skeletal muscle, primarily using findings from mouse models. The first focus of this review is how the differential targeting of nNOS splice variants creates spatially and functionally distinct nitric oxide (NO) signaling compartments at the sarcolemma, Golgi complex, and cytoplasm. Particular attention is given to the functions of sarcolemmal nNOSμ and limitations of current nNOS knockout models. The second major focus is to review current understanding of cGMP-mediated nNOS signaling in skeletal muscle and its emergence as a therapeutic target in DMD and BMD. Accordingly, we address the preclinical and clinical successes and setbacks with the testing of phosphodiesterase 5 inhibitors to redress nNOS signaling defects in DMD and BMD. In summary, this review of nNOS function in normal and dystrophic muscle aims to advance understanding how the messenger NO is harnessed for cellular signaling from a skeletal muscle perspective.
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Affiliation(s)
- Jordan E Balke
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine Miami, Florida, 33101, USA
| | - Ling Zhang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine Miami, Florida, 33101, USA
| | - Justin M Percival
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine Miami, Florida, 33101, USA.
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10
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Patel A, Zhao J, Yue Y, Zhang K, Duan D, Lai Y. Dystrophin R16/17-syntrophin PDZ fusion protein restores sarcolemmal nNOSμ. Skelet Muscle 2018; 8:36. [PMID: 30466494 PMCID: PMC6251231 DOI: 10.1186/s13395-018-0182-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 11/07/2018] [Indexed: 12/18/2022] Open
Abstract
Background Loss of sarcolemmal nNOSμ is a common manifestation in a wide variety of muscle diseases and contributes to the dysregulation of multiple muscle activities. Given the critical role sarcolemmal nNOSμ plays in muscle, restoration of sarcolemmal nNOSμ should be considered as an important therapeutic goal. Methods nNOSμ is anchored to the sarcolemma by dystrophin spectrin-like repeats 16 and 17 (R16/17) and the syntrophin PDZ domain (Syn PDZ). To develop a strategy that can independently restore sarcolemmal nNOSμ, we engineered an R16/17-Syn PDZ fusion construct and tested whether this construct alone is sufficient to anchor nNOSμ to the sarcolemma in three different mouse models of Duchenne muscular dystrophy (DMD). Results Membrane-associated nNOSμ is completely lost in DMD. Adeno-associated virus (AAV)-mediated delivery of the R16/17-Syn PDZ fusion construct successfully restored sarcolemmal nNOSμ in all three models. Further, nNOS restoration was independent of the dystrophin-associated protein complex. Conclusions Our results suggest that the R16/17-Syn PDZ fusion construct is sufficient to restore sarcolemmal nNOSμ in the dystrophin-null muscle. Electronic supplementary material The online version of this article (10.1186/s13395-018-0182-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Aman Patel
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Medical Sciences Building, One Hospital Drive, Columbia, MO, 65212, USA
| | - Junling Zhao
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Medical Sciences Building, One Hospital Drive, Columbia, MO, 65212, USA
| | - Yongping Yue
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Medical Sciences Building, One Hospital Drive, Columbia, MO, 65212, USA
| | - Keqing Zhang
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Medical Sciences Building, One Hospital Drive, Columbia, MO, 65212, USA
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Medical Sciences Building, One Hospital Drive, Columbia, MO, 65212, USA. .,Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65212, USA. .,Department of Neurology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA. .,Department of Bioengineering, University of Missouri, Columbia, MO, 65212, USA.
| | - Yi Lai
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Medical Sciences Building, One Hospital Drive, Columbia, MO, 65212, USA.
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11
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Zhou QG, Zhu XH, Nemes AD, Zhu DY. Neuronal nitric oxide synthase and affective disorders. IBRO Rep 2018; 5:116-132. [PMID: 30591953 PMCID: PMC6303682 DOI: 10.1016/j.ibror.2018.11.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 11/07/2018] [Accepted: 11/13/2018] [Indexed: 01/08/2023] Open
Abstract
Affective disorders including major depressive disorder (MDD), bipolar disorder (BPD), and general anxiety affect more than 10% of population in the world. Notably, neuronal nitric oxide synthase (nNOS), a downstream signal molecule of N-methyl-D-aspartate receptors (NMDARs) activation, is abundant in many regions of the brain such as the prefrontal cortex (PFC), hippocampus, amygdala, dorsal raphe nucleus (DRN), locus coeruleus (LC), and hypothalamus, which are closely associated with the pathophysiology of affective disorders. Decreased levels of the neurotransmitters including 5-hydroxytryptamine or serotonin (5-HT), noradrenalin (NA), and dopamine (DA) as well as hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis are common pathological changes of MDD, BPD, and anxiety. Increasing data suggests that nNOS in the hippocampus play a crucial role in the etiology of MDD whereas nNOS-related dysregulation of the nitrergic system in the LC is closely associated with the pathogenesis of BPD. Moreover, hippocampal nNOS is implicated in the role of serotonin receptor 1 A (5-HTR1 A) in modulating anxiety behaviors. Augment of nNOS and its carboxy-terminal PDZ ligand (CAPON) complex mediate stress-induced anxiety and disrupting the nNOS-CAPON interaction by small molecular drug generates anxiolytic effect. To date, however, the function of nNOS in affective disorders is not well reviewed. Here, we summarize works about nNOS and its signal mechanisms implicated in the pathophysiology of affective disorders. On the basis of this review, it is suggested that future research should more fully focus on the role of nNOS in the pathomechanism and treatment of affective disorders.
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Affiliation(s)
- Qi-Gang Zhou
- Department of Clinical Pharmacology, Pharmacy College, Nanjing Medical University, Nanjing 211166, PR China
| | - Xian-Hui Zhu
- Department of Clinical Pharmacology, Pharmacy College, Nanjing Medical University, Nanjing 211166, PR China
| | - Ashley D Nemes
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, USA
| | - Dong-Ya Zhu
- Department of Clinical Pharmacology, Pharmacy College, Nanjing Medical University, Nanjing 211166, PR China
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12
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Dombernowsky NW, Ölmestig JNE, Witting N, Kruuse C. Role of neuronal nitric oxide synthase (nNOS) in Duchenne and Becker muscular dystrophies - Still a possible treatment modality? Neuromuscul Disord 2018; 28:914-926. [PMID: 30352768 DOI: 10.1016/j.nmd.2018.09.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 08/07/2018] [Accepted: 09/05/2018] [Indexed: 02/08/2023]
Abstract
Neuronal nitric oxide synthase (nNOS) is involved in nitric oxide (NO) production and suggested to play a crucial role in blood flow regulation of skeletal muscle. During activation of the muscle, NO helps attenuate the sympathetic vasoconstriction to accommodate increased metabolic demands, a phenomenon known as functional sympatholysis. In inherited myopathies such as the dystrophinopathies Duchenne and Becker muscle dystrophies (DMD and BMD), nNOS is lost from the sarcolemma. The loss of nNOS may cause functional ischemia contributing to skeletal and cardiac muscle cell injury. Effects of NO is augmented by inhibiting degradation of the second messenger cyclic guanosine monophosphate (cGMP) using sildenafil and tadalafil, both of which inhibit the enzyme phosphodiesterase 5 (PDE5). In animal models of DMD, PDE5-inhibitors prevent functional ischemia, reduce post-exercise skeletal muscle pathology and fatigue, show amelioration of cardiac muscle cell damage and increase cardiac performance. However, effect on clinical outcomes in DMD and BMD patients have been disappointing with minor effects on upper limb performance and none on ambulation. This review aims to summarize the current knowledge of nNOS function related to functional sympatholysis in skeletal muscle and studies on PDE5-inhibitor treatment in nNOS-deficient animal models and patients.
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Affiliation(s)
- Nanna W Dombernowsky
- Department of Neurology, Rigshospitalet Glostrup, University of Copenhagen, Denmark
| | - Joakim N E Ölmestig
- Department of Neurology, Neurovascular Research Unit, Herlev Gentofte Hospital, University of Copenhagen, Denmark
| | - Nanna Witting
- Department of Neurology, Rigshospitalet Glostrup, University of Copenhagen, Denmark
| | - Christina Kruuse
- Department of Neurology, Neurovascular Research Unit, Herlev Gentofte Hospital, University of Copenhagen, Denmark; PDE Research Group, Lundbeck Foundation Center for Neurovascular Research (LUCENS), Denmark.
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13
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Kerrick WGL, Xu Y, Percival JM. nNOS splice variants differentially regulate myofilament function but are dispensable for intracellular calcium and force transients in cardiac papillary muscles. PLoS One 2018; 13:e0200834. [PMID: 30028847 PMCID: PMC6054407 DOI: 10.1371/journal.pone.0200834] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 07/02/2018] [Indexed: 11/18/2022] Open
Abstract
Cardiac muscle expresses three neuronal nitric oxide synthase (nNOS) splice variants: nNOSα, nNOSμ and nNOSβ. The functions of these nNOS splice variants in cardiac muscle, particularly myofilament-associated nNOSβ are unclear. To decipher cardiac nNOS splice variant function we investigated myofilament function and intracellular calcium and force transients in demembranated and intact papillary muscles from two lines of nNOS knockout mice. The first line (KN1) lacks nNOSα and nNOSμ. The second line (KN2) lacks active nNOSα, nNOSμ and nNOSβ. Demembranated KN1 papillary muscles exhibited reduced myofilament ATPase activity (-35%) and specific force (-10%) relative to controls. Demembranated KN2 muscles exhibited a smaller decrease in myofilament ATPase activity (-21%), but a greater reduction in specific force (-26%) relative to controls. Myofilament calcium sensitivity in demembranated KN1 and KN2 papillary muscles was similar to controls. Thus, papillary muscle-expressed nNOS splice variants are necessary for control levels of myofilament ATPase activity and force generation, but dispensable for myofilament calcium sensitivity. The greater reduction in myofilament ATPase relative to specific force in KN1, but not KN2 muscle, reduced the energy cost of muscle contraction, suggesting that nNOSβ increased the energetic efficiency of contraction in the absence of nNOSμ and nNOSα. Analyses of intact KN1 and KN2 papillary muscles showed that both intracellular calcium transients and their evoked force transients were similar to controls at stimulation frequencies between 1 and 3 Hz. Therefore, nNOS was dispensable for baseline excitation-contraction coupling. In summary, these data suggest that nNOS splice variants differentially regulate myofilament function, but not baseline calcium handling in papillary muscles. More importantly, they suggest that nNOSβ is a novel modulator of myofilament function, and ultimately the energetic efficiency of cardiac papillary muscle contraction.
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Affiliation(s)
- W Glenn L Kerrick
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Yuanyuan Xu
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Justin M Percival
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
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14
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Barbé C, Bray F, Gueugneau M, Devassine S, Lause P, Tokarski C, Rolando C, Thissen JP. Comparative Proteomic and Transcriptomic Analysis of Follistatin-Induced Skeletal Muscle Hypertrophy. J Proteome Res 2017; 16:3477-3490. [PMID: 28810121 DOI: 10.1021/acs.jproteome.7b00069] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Skeletal muscle, the most abundant body tissue, plays vital roles in locomotion and metabolism. Myostatin is a negative regulator of skeletal muscle mass. In addition to increasing muscle mass, Myostatin inhibition impacts muscle contractility and energy metabolism. To decipher the mechanisms of action of the Myostatin inhibitors, we used proteomic and transcriptomic approaches to investigate the changes induced in skeletal muscles of transgenic mice overexpressing Follistatin, a physiological Myostatin inhibitor. Our proteomic workflow included a fractionation step to identify weakly expressed proteins and a comparison of fast versus slow muscles. Functional annotation of altered proteins supports the phenotypic changes induced by Myostatin inhibition, including modifications in energy metabolism, fiber type, insulin and calcium signaling, as well as membrane repair and regeneration. Less than 10% of the differentially expressed proteins were found to be also regulated at the mRNA level but the Biological Process annotation, and the KEGG pathways analysis of transcriptomic results shows a great concordance with the proteomic data. Thus this study describes the most extensive omics analysis of muscle overexpressing Follistatin, providing molecular-level insights to explain the observed muscle phenotypic changes.
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Affiliation(s)
- Caroline Barbé
- Pole of Endocrinology, Diabetes and Nutrition, Institute of Experimental and Clinical Research, Université Catholique de Louvain , 1200 Brussels, Belgium
| | - Fabrice Bray
- Miniaturisation pour la Synthèse, l'Analyse & la Protéomique (MSAP), CNRS, USR 3290, Université de Lille; Biochimie Structurale & Fonctionnelle des Assemblages Biomoléculaires, CNRS, FR 3688, FRABIO, Université de Lille and Institut Eugène-Michel Chevreul, CNRS, FR 2638, Université de Lille, 59000 Lille, France
| | - Marine Gueugneau
- Pole of Endocrinology, Diabetes and Nutrition, Institute of Experimental and Clinical Research, Université Catholique de Louvain , 1200 Brussels, Belgium
| | - Stéphanie Devassine
- Miniaturisation pour la Synthèse, l'Analyse & la Protéomique (MSAP), CNRS, USR 3290, Université de Lille; Biochimie Structurale & Fonctionnelle des Assemblages Biomoléculaires, CNRS, FR 3688, FRABIO, Université de Lille and Institut Eugène-Michel Chevreul, CNRS, FR 2638, Université de Lille, 59000 Lille, France
| | - Pascale Lause
- Pole of Endocrinology, Diabetes and Nutrition, Institute of Experimental and Clinical Research, Université Catholique de Louvain , 1200 Brussels, Belgium
| | - Caroline Tokarski
- Miniaturisation pour la Synthèse, l'Analyse & la Protéomique (MSAP), CNRS, USR 3290, Université de Lille; Biochimie Structurale & Fonctionnelle des Assemblages Biomoléculaires, CNRS, FR 3688, FRABIO, Université de Lille and Institut Eugène-Michel Chevreul, CNRS, FR 2638, Université de Lille, 59000 Lille, France
| | - Christian Rolando
- Miniaturisation pour la Synthèse, l'Analyse & la Protéomique (MSAP), CNRS, USR 3290, Université de Lille; Biochimie Structurale & Fonctionnelle des Assemblages Biomoléculaires, CNRS, FR 3688, FRABIO, Université de Lille and Institut Eugène-Michel Chevreul, CNRS, FR 2638, Université de Lille, 59000 Lille, France
| | - Jean-Paul Thissen
- Pole of Endocrinology, Diabetes and Nutrition, Institute of Experimental and Clinical Research, Université Catholique de Louvain , 1200 Brussels, Belgium
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15
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Moon Y, Balke JE, Madorma D, Siegel MP, Knowels G, Brouckaert P, Buys ES, Marcinek DJ, Percival JM. Nitric Oxide Regulates Skeletal Muscle Fatigue, Fiber Type, Microtubule Organization, and Mitochondrial ATP Synthesis Efficiency Through cGMP-Dependent Mechanisms. Antioxid Redox Signal 2017; 26:966-985. [PMID: 27393340 PMCID: PMC5467110 DOI: 10.1089/ars.2016.6630] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AIM Skeletal muscle nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathways are impaired in Duchenne and Becker muscular dystrophy partly because of reduced nNOSμ and soluble guanylate cyclase (GC) activity. However, GC function and the consequences of reduced GC activity in skeletal muscle are unknown. In this study, we explore the functions of GC and NO-cGMP signaling in skeletal muscle. RESULTS GC1, but not GC2, expression was higher in oxidative than glycolytic muscles. GC1 was found in a complex with nNOSμ and targeted to nNOS compartments at the Golgi complex and neuromuscular junction. Baseline GC activity and GC agonist responsiveness was reduced in the absence of nNOS. Structural analyses revealed aberrant microtubule directionality in GC1-/- muscle. Functional analyses of GC1-/- muscles revealed reduced fatigue resistance and postexercise force recovery that were not due to shifts in type IIA-IIX fiber balance. Force deficits in GC1-/- muscles were also not driven by defects in resting mitochondrial adenosine triphosphate (ATP) synthesis. However, increasing muscle cGMP with sildenafil decreased ATP synthesis efficiency and capacity, without impacting mitochondrial content or ultrastructure. INNOVATION GC may represent a new target for alleviating muscle fatigue and that NO-cGMP signaling may play important roles in muscle structure, contractility, and bioenergetics. CONCLUSIONS These findings suggest that GC activity is nNOS dependent and that muscle-specific control of GC expression and differential GC targeting may facilitate NO-cGMP signaling diversity. They suggest that nNOS regulates muscle fiber type, microtubule organization, fatigability, and postexercise force recovery partly through GC1 and suggest that NO-cGMP pathways may modulate mitochondrial ATP synthesis efficiency. Antioxid. Redox Signal. 26, 966-985.
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Affiliation(s)
- Younghye Moon
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida
| | - Jordan E Balke
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida
| | - Derik Madorma
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida
| | - Michael P Siegel
- 2 Department of Bioengineering, University of Washington , Seattle, Washington
| | - Gary Knowels
- 2 Department of Bioengineering, University of Washington , Seattle, Washington
| | - Peter Brouckaert
- 3 Department for Molecular Biomedical Research and Biomedical Molecular Biology, Ghent University , Ghent, Belgium
| | - Emmanuel S Buys
- 4 Department of Anesthesia, Critical Care and Pain Medicine, Anesthesia Center for Critical Care Research , Massachusetts General Hospital, Boston, Massachusetts
| | - David J Marcinek
- 2 Department of Bioengineering, University of Washington , Seattle, Washington.,5 Department of Radiology, University of Washington , Seattle, Washington
| | - Justin M Percival
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida
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16
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Moon Y, Cao Y, Zhu J, Xu Y, Balkan W, Buys ES, Diaz F, Kerrick WG, Hare JM, Percival JM. GSNOR Deficiency Enhances In Situ Skeletal Muscle Strength, Fatigue Resistance, and RyR1 S-Nitrosylation Without Impacting Mitochondrial Content and Activity. Antioxid Redox Signal 2017; 26:165-181. [PMID: 27412893 PMCID: PMC5278832 DOI: 10.1089/ars.2015.6548] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIM Nitric oxide (NO) plays important, but incompletely defined roles in skeletal muscle. NO exerts its regulatory effects partly though S-nitrosylation, which is balanced by denitrosylation by enzymes such as S-nitrosoglutathione reductase (GSNOR), whose functions in skeletal muscle remain to be fully deciphered. RESULTS GSNOR null (GSNOR-/-) tibialis anterior (TA) muscles showed normal growth and were stronger and more fatigue resistant than controls in situ. However, GSNOR-/- lumbrical muscles showed normal contractility and Ca2+ handling in vitro, suggesting important differences in GSNOR function between muscles or between in vitro and in situ environments. GSNOR-/- TA muscles exhibited normal mitochondrial content, and capillary densities, but reduced type IIA fiber content. GSNOR inhibition did not impact mitochondrial respiratory complex I, III, or IV activities. These findings argue that enhanced GSNOR-/- TA contractility is not driven by changes in mitochondrial content or activity, fiber type, or blood vessel density. However, loss of GSNOR led to RyR1 hypernitrosylation, which is believed to increase muscle force output under physiological conditions. cGMP synthesis by soluble guanylate cyclase (sGC) was decreased in resting GSNOR-/- muscle and was more responsive to agonist (DETANO, BAY 41, and BAY 58) stimulation, suggesting that GSNOR modulates cGMP production in skeletal muscle. INNOVATION GSNOR may act as a "brake" on skeletal muscle contractile performance under physiological conditions by modulating nitrosylation/denitrosylation balance. CONCLUSIONS GSNOR may play important roles in skeletal muscle contractility, RyR1 S-nitrosylation, fiber type specification, and sGC activity. Antioxid. Redox Signal. 26, 165-181.
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Affiliation(s)
- Younghye Moon
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida
| | - Yenong Cao
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida.,2 The Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine , Miami, Florida
| | - Jingjing Zhu
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida
| | - Yuanyuan Xu
- 3 Department of Physiology and Biophysics, University of Miami Miller School of Medicine , Miami, Florida
| | - Wayne Balkan
- 2 The Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine , Miami, Florida.,4 Department of Medicine, University of Miami Miller School of Medicine , Miami, Florida
| | - Emmanuel S Buys
- 5 Department of Anesthesia, Critical Care and Pain Medicine, Anesthesia Center for Critical Care Research , Harvard Medical School, Massachusetts General Hospital Boston, Boston, Massachusetts
| | - Francisca Diaz
- 6 Department of Neurology, University of Miami Miller School of Medicine , Miami, Florida
| | - W Glenn Kerrick
- 3 Department of Physiology and Biophysics, University of Miami Miller School of Medicine , Miami, Florida
| | - Joshua M Hare
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida.,2 The Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine , Miami, Florida.,4 Department of Medicine, University of Miami Miller School of Medicine , Miami, Florida
| | - Justin M Percival
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida
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17
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Hogarth MW, Houweling PJ, Thomas KC, Gordish-Dressman H, Bello L, Pegoraro E, Hoffman EP, Head SI, North KN. Evidence for ACTN3 as a genetic modifier of Duchenne muscular dystrophy. Nat Commun 2017; 8:14143. [PMID: 28139640 PMCID: PMC5290331 DOI: 10.1038/ncomms14143] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 11/22/2016] [Indexed: 01/01/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is characterized by muscle degeneration and progressive weakness. There is considerable inter-patient variability in disease onset and progression, which can confound the results of clinical trials. Here we show that a common null polymorphism (R577X) in ACTN3 results in significantly reduced muscle strength and a longer 10 m walk test time in young, ambulant patients with DMD; both of which are primary outcome measures in clinical trials. We have developed a double knockout mouse model, which also shows reduced muscle strength, but is protected from stretch-induced eccentric damage with age. This suggests that α-actinin-3 deficiency reduces muscle performance at baseline, but ameliorates the progression of dystrophic pathology. Mechanistically, we show that α-actinin-3 deficiency triggers an increase in oxidative muscle metabolism through activation of calcineurin, which likely confers the protective effect. Our studies suggest that ACTN3 R577X genotype is a modifier of clinical phenotype in DMD patients.
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Affiliation(s)
- Marshall W Hogarth
- Institute for Neuroscience and Muscle Research, The Children's Hospital Westmead, New South Wales 2145, Australia.,Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, New South Wales 2006, Australia
| | - Peter J Houweling
- Institute for Neuroscience and Muscle Research, The Children's Hospital Westmead, New South Wales 2145, Australia.,School of Medical Sciences, University of New South Wales, New South Wales 2052, Australia.,Murdoch Childrens Research Institute, Melbourne, Victoria 3052, Australia.,Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Kristen C Thomas
- Institute for Neuroscience and Muscle Research, The Children's Hospital Westmead, New South Wales 2145, Australia
| | - Heather Gordish-Dressman
- Research Centre for Genetic Medicine, Children's National Medical Centre, Washington DC 20010, USA
| | - Luca Bello
- Research Centre for Genetic Medicine, Children's National Medical Centre, Washington DC 20010, USA.,Department of Neurosciences, University of Padova, Padova 35122, Italy
| | | | - Elena Pegoraro
- Department of Neurosciences, University of Padova, Padova 35122, Italy
| | - Eric P Hoffman
- Research Centre for Genetic Medicine, Children's National Medical Centre, Washington DC 20010, USA
| | - Stewart I Head
- School of Medical Sciences, University of New South Wales, New South Wales 2052, Australia
| | - Kathryn N North
- Institute for Neuroscience and Muscle Research, The Children's Hospital Westmead, New South Wales 2145, Australia.,Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, New South Wales 2006, Australia.,Murdoch Childrens Research Institute, Melbourne, Victoria 3052, Australia.,Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria 3010, Australia
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18
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The maintenance ability and Ca 2+ availability of skeletal muscle are enhanced by sildenafil. Exp Mol Med 2016; 48:e278. [PMID: 27932789 PMCID: PMC5192075 DOI: 10.1038/emm.2016.134] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 09/08/2016] [Accepted: 09/22/2016] [Indexed: 12/23/2022] Open
Abstract
Sildenafil relaxes vascular smooth muscle cells and is used to treat pulmonary artery hypertension as well as erectile dysfunction. However, the effectiveness of sildenafil on skeletal muscle and the benefit of its clinical use have been controversial, and most studies focus primarily on tissues and organs from disease models without cellular examination. Here, the effects of sildenafil on skeletal muscle at the cellular level were examined using mouse primary skeletal myoblasts (the proliferative form of skeletal muscle stem cells) and myotubes, along with single-cell Ca2+ imaging experiments and cellular and biochemical studies. The proliferation of skeletal myoblasts was enhanced by sildenafil in a dose-independent manner. In skeletal myotubes, sildenafil enhanced the activity of ryanodine receptor 1, an internal Ca2+ channel, and Ca2+ movement that promotes skeletal muscle contraction, possibly due to an increase in the resting cytosolic Ca2+ level and a unique microscopic shape in the myotube membranes. Therefore, these results suggest that the maintenance ability of skeletal muscle mass and the contractility of skeletal muscle could be improved by sildenafil by enhancing the proliferation of skeletal myoblasts and increasing the Ca2+ availability of skeletal myotubes, respectively.
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19
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Hord JM, Botchlett R, Lawler JM. Age-related alterations in the sarcolemmal environment are attenuated by lifelong caloric restriction and voluntary exercise. Exp Gerontol 2016; 83:148-57. [PMID: 27534381 DOI: 10.1016/j.exger.2016.08.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 07/25/2016] [Accepted: 08/10/2016] [Indexed: 10/21/2022]
Abstract
Age-related loss of skeletal muscle mass and function, referred to as sarcopenia, is mitigated by lifelong calorie restriction as well as exercise. In aged skeletal muscle fibers there is compromised integrity of the cell membrane that may contribute to sarcopenia. The purpose of this study was to determine if lifelong mild (8%) caloric restriction (CR) and lifelong CR+voluntary wheel running (WR) could ameliorate disruption of membrane scaffolding and signaling proteins during the aging process, thus maintaining a favorable, healthy membrane environment in plantaris muscle fibers. Fischer-344 rats were divided into four groups: 24-month old adults fed ad libitum (OAL); 24-month old on 8% caloric restriction (OCR); 24month old 8% caloric restriction+wheel running (OCRWR); and 6-month old sedentary adults fed ad libitum (YAL) were used to determine age-related changes. Aging resulted in discontinuous membrane expression of dystrophin glycoprotein complex (DGC) proteins: dystrophin and α-syntrophin. Older muscle also displayed decreased content of neuronal nitric oxide synthase (nNOS), a key DGC signaling protein. In contrast, OCR and OCRWR provided significant protection against age-related DGC disruption. In conjunction with the age-related decline in membrane DGC patency, key membrane repair proteins (MG53, dysferlin, annexin A6, and annexin A2) were significantly increased in the OAL plantaris. However, lifelong CR and CRWR interventions were effective at maintaining membrane repair proteins near YAL levels of. OAL fibers also displayed reduced protein content of NADPH oxidase isoform 2 (Nox2) subunits (p67phox and p47phox), consistent with a perturbed sarcolemmal environment. Loss of Nox2 subunits was prevented by lifelong CR and CRWR. Our results are therefore consistent with the hypothesis that lifelong CR and WR are effective countermeasures against age-related alterations in the myofiber membrane environment.
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Affiliation(s)
- Jeffrey M Hord
- Redox Biology & Cell Signaling Laboratory, Department of Health and Kinesiology, College of Education and Human Development, Texas A&M University, College Station, TX, United States
| | - Rachel Botchlett
- Department of Nutrition & Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX, United States
| | - John M Lawler
- Redox Biology & Cell Signaling Laboratory, Department of Health and Kinesiology, College of Education and Human Development, Texas A&M University, College Station, TX, United States; Department of Nutrition & Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX, United States.
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Chaudhury A. Response: "Commentary: A Hypothesis for Examining Skeletal Muscle Biopsy-Derived Sarcolemmal nNOSµ as Surrogate for Enteric nNOSα Function". nNOS(skeletal muscle) may be Evidentiary for Enteric NO-Transmission Despite nNOSµ/α Differences. Front Med (Lausanne) 2016; 3:4. [PMID: 26942180 PMCID: PMC4761842 DOI: 10.3389/fmed.2016.00004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 01/15/2016] [Indexed: 12/15/2022] Open
Affiliation(s)
- Arun Chaudhury
- Arkansas Department of Health and GIM Foundation , Little Rock, AR , USA
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21
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Allen DG, Whitehead NP, Froehner SC. Absence of Dystrophin Disrupts Skeletal Muscle Signaling: Roles of Ca2+, Reactive Oxygen Species, and Nitric Oxide in the Development of Muscular Dystrophy. Physiol Rev 2016; 96:253-305. [PMID: 26676145 DOI: 10.1152/physrev.00007.2015] [Citation(s) in RCA: 272] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Dystrophin is a long rod-shaped protein that connects the subsarcolemmal cytoskeleton to a complex of proteins in the surface membrane (dystrophin protein complex, DPC), with further connections via laminin to other extracellular matrix proteins. Initially considered a structural complex that protected the sarcolemma from mechanical damage, the DPC is now known to serve as a scaffold for numerous signaling proteins. Absence or reduced expression of dystrophin or many of the DPC components cause the muscular dystrophies, a group of inherited diseases in which repeated bouts of muscle damage lead to atrophy and fibrosis, and eventually muscle degeneration. The normal function of dystrophin is poorly defined. In its absence a complex series of changes occur with multiple muscle proteins showing reduced or increased expression or being modified in various ways. In this review, we will consider the various proteins whose expression and function is changed in muscular dystrophies, focusing on Ca(2+)-permeable channels, nitric oxide synthase, NADPH oxidase, and caveolins. Excessive Ca(2+) entry, increased membrane permeability, disordered caveolar function, and increased levels of reactive oxygen species are early changes in the disease, and the hypotheses for these phenomena will be critically considered. The aim of the review is to define the early damage pathways in muscular dystrophy which might be appropriate targets for therapy designed to minimize the muscle degeneration and slow the progression of the disease.
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Affiliation(s)
- David G Allen
- Sydney Medical School & Bosch Institute, University of Sydney, New South Wales, Australia; and Department of Physiology & Biophysics, University of Washington, Seattle, Washington
| | - Nicholas P Whitehead
- Sydney Medical School & Bosch Institute, University of Sydney, New South Wales, Australia; and Department of Physiology & Biophysics, University of Washington, Seattle, Washington
| | - Stanley C Froehner
- Sydney Medical School & Bosch Institute, University of Sydney, New South Wales, Australia; and Department of Physiology & Biophysics, University of Washington, Seattle, Washington
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Betteridge S, Bescós R, Martorell M, Pons A, Garnham AP, Stathis CC, McConell GK. No effect of acute beetroot juice ingestion on oxygen consumption, glucose kinetics, or skeletal muscle metabolism during submaximal exercise in males. J Appl Physiol (1985) 2016; 120:391-8. [DOI: 10.1152/japplphysiol.00658.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 11/26/2015] [Indexed: 01/08/2023] Open
Abstract
Beetroot juice, which is rich in nitrate (NO3−), has been shown in some studies to decrease oxygen consumption (V̇o2) for a given exercise workload, i.e., increasing efficiency and exercise tolerance. Few studies have examined the effect of beetroot juice or nitrate supplementation on exercise metabolism. Eight healthy recreationally active males participated in three trials involving ingestion of either beetroot juice (Beet; ∼8 mmol NO3−), Placebo (nitrate-depleted Beet), or Beet + mouthwash (Beet+MW), all of which were performed in a randomized single-blind crossover design. Two-and-a-half hours later, participants cycled for 60 min on an ergometer at 65% of V̇o2 peak. [6,6-2H]glucose was infused to determine glucose kinetics, blood samples obtained throughout exercise, and skeletal muscle biopsies that were obtained pre- and postexercise. Plasma nitrite [NO2−] increased significantly (∼130%) with Beet, and this was attenuated in MW+Beet. Beet and Beet+MW had no significant effect on oxygen consumption, blood glucose, blood lactate, plasma nonesterified fatty acids, or plasma insulin during exercise. Beet and Beet+MW also had no significant effect on the increase in glucose disposal during exercise. In addition, Beet and Beet+MW had no significant effect on the decrease in muscle glycogen and phosphocreatine and the increase in muscle creatine, lactate, and phosphorylated acetyl CoA carboxylase during exercise. In conclusion, at the dose used, acute ingestion of beetroot juice had little effect on skeletal muscle metabolism during exercise.
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Affiliation(s)
- Scott Betteridge
- College of Health and Biomedicine, Victoria University, Melbourne, Australia
- Institute of Sport, Exercise and Active Living, College of Sport and Exercise Science, Victoria University, Melbourne, Australia
| | - Raúl Bescós
- Institute of Sport, Exercise and Active Living, College of Sport and Exercise Science, Victoria University, Melbourne, Australia
| | - Miquel Martorell
- Laboratory of Physical Activity Science, Research Group on Community Nutrition and Oxidative Stress, University of Balearic Islands, Palma Mallorca, Spain
- Nutrition and Dietetics Department, School of Pharmacy, University of Concepcion, Concepcion, Chile
| | - Antoni Pons
- Laboratory of Physical Activity Science, Research Group on Community Nutrition and Oxidative Stress, University of Balearic Islands, Palma Mallorca, Spain
| | - Andrew P. Garnham
- School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Australia; and
| | - Christos C. Stathis
- College of Health and Biomedicine, Victoria University, Melbourne, Australia
| | - Glenn K. McConell
- College of Health and Biomedicine, Victoria University, Melbourne, Australia
- Institute of Sport, Exercise and Active Living, College of Sport and Exercise Science, Victoria University, Melbourne, Australia
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Rebolledo DL, Kim MJ, Whitehead NP, Adams ME, Froehner SC. Sarcolemmal targeting of nNOSμ improves contractile function of mdx muscle. Hum Mol Genet 2015; 25:158-66. [PMID: 26604149 DOI: 10.1093/hmg/ddv466] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 11/09/2015] [Indexed: 11/13/2022] Open
Abstract
Nitric oxide (NO) is a key regulator of skeletal muscle function and metabolism, including vasoregulation, mitochondrial function, glucose uptake, fatigue and excitation-contraction coupling. The main generator of NO in skeletal muscle is the muscle-specific form of neuronal nitric oxide synthase (nNOSμ) produced by the NOS1 gene. Skeletal muscle nNOSμ is predominantly localized at the sarcolemma by interaction with the dystrophin protein complex (DPC). In Duchenne muscular dystrophy (DMD), loss of dystrophin leads to the mislocalization of nNOSμ from the sarcolemma to the cytosol. This perturbation has been shown to impair contractile function and cause muscle fatigue in dystrophic (mdx) mice. Here, we investigated the effect of restoring sarcolemmal nNOSμ on muscle contractile function in mdx mice. To achieve this, we designed a modified form of nNOSμ (NOS-M) that is targeted to the sarcolemma by palmitoylation, even in the absence of the DPC. When expressed specifically in mdx skeletal muscle, NOS-M significantly attenuates force loss owing to damaging eccentric contractions and repetitive isometric contractions (fatigue), while also improving force recovery after fatigue. Expression of unmodified nNOSμ at similar levels does not lead to sarcolemmal association and fails to improve muscle function. Aside from the benefits of sarcolemmal-localized NO production, NOS-M also increased the surface membrane levels of utrophin and other DPC proteins, including β-dystroglycan, α-syntrophin and α-dystrobrevin in mdx muscle. These results suggest that the expression of NOS-M in skeletal muscle may be therapeutically beneficial in DMD and other muscle diseases characterized by the loss of nNOSμ from the sarcolemma.
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Affiliation(s)
- Daniela L Rebolledo
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195-7290, USA and Departamento de Biología Celular y Molecular, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Min Jeong Kim
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195-7290, USA and
| | - Nicholas P Whitehead
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195-7290, USA and
| | - Marvin E Adams
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195-7290, USA and
| | - Stanley C Froehner
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195-7290, USA and
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Chaudhury A. A Hypothesis for Examining Skeletal Muscle Biopsy-Derived Sarcolemmal nNOSμ as Surrogate for Enteric nNOSα Function. Front Med (Lausanne) 2015; 2:48. [PMID: 26284245 PMCID: PMC4517061 DOI: 10.3389/fmed.2015.00048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/10/2015] [Indexed: 12/13/2022] Open
Abstract
The pathophysiology of gastrointestinal motility disorders is controversial and largely unresolved. This provokes empiric approaches to patient management of these so-called functional gastrointestinal disorders. Preliminary evidence demonstrates that defects in neuronal nitric oxide synthase (nNOS) expression and function, the enzyme that synthesizes nitric oxide (NO), the key inhibitory neurotransmitter mediating mechano-electrical smooth muscle relaxation, is the major pathophysiological basis for sluggishness of oro-aboral transit of luminal contents. This opinion is an ansatz of the potential of skeletal muscle biopsy and examining sarcolemmal nNOSμ to provide complementary insights regarding nNOSα expression, localization, and function within enteric nerve terminals, the site of stimulated de novo NO synthesis. The main basis of this thesis is twofold: (a) the molecular similarity of the structures of nNOS α and μ, similar mechanisms of localizations to “active zones” of nitrergic synthesis, and same mechanisms of electron transfers during NO synthesis and (b) pragmatic difficulty to routinely obtain full-thickness biopsies of gastrointestinal tract, even in patients presenting with the most recalcitrant manifestations of stasis and delayed transit of luminal contents. This opinion attempts to provoke dialog whether this approach is feasible as a surrogate to predict catalytic potential of nNOSα and defects in nitrergic neurotransmission. This discussion makes an assumption that similar molecular mechanisms of nNOS defects shall be operant in both the enteric nerve terminals and the skeletal muscles. These overlaps of skeletal and gastrointestinal dysfunction are largely unknown, thus meriting that the thesis be validated in future by proof-of-principle experiments.
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Neuronal nitric oxide synthase is dislocated in type I fibers of myalgic muscle but can recover with physical exercise training. BIOMED RESEARCH INTERNATIONAL 2015; 2015:265278. [PMID: 25853139 PMCID: PMC4380094 DOI: 10.1155/2015/265278] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 01/24/2015] [Accepted: 02/18/2015] [Indexed: 11/18/2022]
Abstract
Trapezius myalgia is the most common type of chronic neck pain. While physical exercise reduces pain and improves muscle function, the underlying mechanisms remain unclear. Nitric oxide (NO) signaling is important in modulating cellular function, and a dysfunctional neuronal NO synthase (nNOS) may contribute to an ineffective muscle function. This study investigated nNOS expression and localization in chronically painful muscle. Forty-one women clinically diagnosed with trapezius myalgia (MYA) and 18 healthy controls (CON) were included in the case-control study. Subsequently, MYA were randomly assigned to either 10 weeks of specific strength training (SST, n = 18), general fitness training (GFT, n = 15), or health information (REF, n = 8). Distribution of fiber type, cross-sectional area, and sarcolemmal nNOS expression did not differ between MYA and CON. However, MYA showed increased sarcoplasmic nNOS localization (18.8 ± 12 versus 12.8 ± 8%, P = 0.049) compared with CON. SST resulted in a decrease of sarcoplasm-localized nNOS following training (before 18.1 ± 12 versus after 12.0 ± 12%; P = 0,027). We demonstrate that myalgic muscle displays altered nNOS localization and that 10 weeks of strength training normalize these disruptions, which supports previous findings of impaired muscle oxygenation during work tasks and reduced pain following exercise.
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Chen HJC, Spiers JG, Sernia C, Lavidis NA. Response of the nitrergic system to activation of the neuroendocrine stress axis. Front Neurosci 2015; 9:3. [PMID: 25653586 PMCID: PMC4300918 DOI: 10.3389/fnins.2015.00003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 01/05/2015] [Indexed: 12/19/2022] Open
Abstract
Exposure to stressful stimuli causes activation of the hypothalamic-pituitary-adrenal axis which rapidly releases high concentrations of glucocorticoid stress hormones, resulting in increased cellular metabolism and spontaneous oxygen and nitrogen radical formation. High concentrations of nitrogen radicals, including nitric oxide, cause damage to cellular proteins in addition to inhibiting components of the mitochondrial transport chain, leading to cellular energy deficiency. During stress exposure, pharmacological inhibition of nitric oxide production reduces indicators of anxiety- and depressive-like behavior in animal models. Therefore, the purpose of this review is to present an overview of the current literature on stress-evoked changes in the nitrergic system, particularly within neural tissue.
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Affiliation(s)
| | - Jereme G Spiers
- School of Biomedical Sciences, The University of Queensland Brisbane, QLD, Australia
| | - Conrad Sernia
- School of Biomedical Sciences, The University of Queensland Brisbane, QLD, Australia
| | - Nickolas A Lavidis
- School of Biomedical Sciences, The University of Queensland Brisbane, QLD, Australia
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27
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De Palma C, Morisi F, Pambianco S, Assi E, Touvier T, Russo S, Perrotta C, Romanello V, Carnio S, Cappello V, Pellegrino P, Moscheni C, Bassi MT, Sandri M, Cervia D, Clementi E. Deficient nitric oxide signalling impairs skeletal muscle growth and performance: involvement of mitochondrial dysregulation. Skelet Muscle 2014; 4:22. [PMID: 25530838 PMCID: PMC4272808 DOI: 10.1186/s13395-014-0022-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 11/18/2014] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Nitric oxide (NO), generated in skeletal muscle mostly by the neuronal NO synthases (nNOSμ), has profound effects on both mitochondrial bioenergetics and muscle development and function. The importance of NO for muscle repair emerges from the observation that nNOS signalling is defective in many genetically diverse skeletal muscle diseases in which muscle repair is dysregulated. How the effects of NO/nNOSμ on mitochondria impact on muscle function, however, has not been investigated yet. METHODS In this study we have examined the relationship between the NO system, mitochondrial structure/activity and skeletal muscle phenotype/growth/functions using a mouse model in which nNOSμ is absent. Also, NO-induced effects and the NO pathway were dissected in myogenic precursor cells. RESULTS We show that nNOSμ deficiency in mouse skeletal muscle leads to altered mitochondrial bioenergetics and network remodelling, and increased mitochondrial unfolded protein response (UPR(mt)) and autophagy. The absence of nNOSμ is also accompanied by an altered mitochondrial homeostasis in myogenic precursor cells with a decrease in the number of myonuclei per fibre and impaired muscle development at early stages of perinatal growth. No alterations were observed, however, in the overall resting muscle structure, apart from a reduced specific muscle mass and cross sectional areas of the myofibres. Investigating the molecular mechanisms we found that nNOSμ deficiency was associated with an inhibition of the Akt-mammalian target of rapamycin pathway. Concomitantly, the Akt-FoxO3-mitochondrial E3 ubiquitin protein ligase 1 (Mul-1) axis was also dysregulated. In particular, inhibition of nNOS/NO/cyclic guanosine monophosphate (cGMP)/cGMP-dependent-protein kinases induced the transcriptional activity of FoxO3 and increased Mul-1 expression. nNOSμ deficiency was also accompanied by functional changes in muscle with reduced muscle force, decreased resistance to fatigue and increased degeneration/damage post-exercise. CONCLUSIONS Our results indicate that nNOSμ/NO is required to regulate key homeostatic mechanisms in skeletal muscle, namely mitochondrial bioenergetics and network remodelling, UPR(mt) and autophagy. These events are likely associated with nNOSμ-dependent impairments of muscle fibre growth resulting in a deficit of muscle performance.
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Affiliation(s)
- Clara De Palma
- Unit of Clinical Pharmacology, National Research Council-Institute of Neuroscience, Department of Biomedical and Clinical Sciences "Luigi Sacco", University Hospital "Luigi Sacco", Università di Milano, Milano, Italy
| | - Federica Morisi
- Unit of Clinical Pharmacology, National Research Council-Institute of Neuroscience, Department of Biomedical and Clinical Sciences "Luigi Sacco", University Hospital "Luigi Sacco", Università di Milano, Milano, Italy
| | - Sarah Pambianco
- Unit of Clinical Pharmacology, National Research Council-Institute of Neuroscience, Department of Biomedical and Clinical Sciences "Luigi Sacco", University Hospital "Luigi Sacco", Università di Milano, Milano, Italy
| | - Emma Assi
- Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy
| | - Thierry Touvier
- Unit of Clinical Pharmacology, National Research Council-Institute of Neuroscience, Department of Biomedical and Clinical Sciences "Luigi Sacco", University Hospital "Luigi Sacco", Università di Milano, Milano, Italy
| | - Stefania Russo
- Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy
| | - Cristiana Perrotta
- Unit of Clinical Pharmacology, National Research Council-Institute of Neuroscience, Department of Biomedical and Clinical Sciences "Luigi Sacco", University Hospital "Luigi Sacco", Università di Milano, Milano, Italy
| | - Vanina Romanello
- Dulbecco Telethon Institute at Venetian Institute of Molecular Medicine, Padova, Italy
| | - Silvia Carnio
- Dulbecco Telethon Institute at Venetian Institute of Molecular Medicine, Padova, Italy
| | - Valentina Cappello
- National Research Council-Institute of Neuroscience, Department of Medical Biotechnology and Translational Medicine, Università di Milano, Milano, Italy ; CNI@NEST, Italian Institute of Technology, Pisa, Italy
| | - Paolo Pellegrino
- Unit of Clinical Pharmacology, National Research Council-Institute of Neuroscience, Department of Biomedical and Clinical Sciences "Luigi Sacco", University Hospital "Luigi Sacco", Università di Milano, Milano, Italy
| | - Claudia Moscheni
- Unit of Morphology, Department of Biomedical and Clinical Sciences "Luigi Sacco", Università di Milano, Milano, Italy
| | | | - Marco Sandri
- Dulbecco Telethon Institute at Venetian Institute of Molecular Medicine, Padova, Italy ; Department of Biomedical Science, Università di Padova, Padova, Italy
| | - Davide Cervia
- Unit of Clinical Pharmacology, National Research Council-Institute of Neuroscience, Department of Biomedical and Clinical Sciences "Luigi Sacco", University Hospital "Luigi Sacco", Università di Milano, Milano, Italy ; Department for Innovation in Biological, Agro-food and Forest Systems, Università della Tuscia, Viterbo, Italy
| | - Emilio Clementi
- Unit of Clinical Pharmacology, National Research Council-Institute of Neuroscience, Department of Biomedical and Clinical Sciences "Luigi Sacco", University Hospital "Luigi Sacco", Università di Milano, Milano, Italy ; Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy
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28
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Froehner SC, Reed SM, Anderson KN, Huang PL, Percival JM. Loss of nNOS inhibits compensatory muscle hypertrophy and exacerbates inflammation and eccentric contraction-induced damage in mdx mice. Hum Mol Genet 2014; 24:492-505. [PMID: 25214536 DOI: 10.1093/hmg/ddu469] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Approaches targeting nitric oxide (NO) signaling show promise as therapies for Duchenne and Becker muscular dystrophies. However, the mechanisms by which NO benefits dystrophin-deficient muscle remain unclear, but may involve nNOSβ, a newly discovered enzymatic source of NO in skeletal muscle. Here we investigate the impact of dystrophin deficiency on nNOSβ and use mdx mice engineered to lack nNOSμ and nNOSβ to discern how the loss of nNOS impacts dystrophic skeletal muscle pathology. In mdx muscle, nNOSβ was mislocalized and its association with the Golgi complex was reduced. nNOS depletion from mdx mice prevented compensatory skeletal muscle cell hypertrophy, decreased myofiber central nucleation and increased focal macrophage cell infiltration, indicating exacerbated dystrophic muscle damage. Reductions in muscle integrity in nNOS-null mdx mice were accompanied by decreases in specific force and increased susceptibility to eccentric contraction-induced muscle damage compared with mdx controls. Unexpectedly, muscle fatigue was unaffected by nNOS depletion, revealing a novel latent compensatory mechanism for the loss of nNOS in mdx mice. Together with previous studies, these data suggest that localization of both nNOSμ and nNOSβ is disrupted by dystrophin deficiency. They also indicate that nNOS has a more complex role as a modifier of dystrophic pathology and broader therapeutic potential than previously recognized. Importantly, these findings also suggest nNOSβ as a new drug target and provide a new conceptual framework for understanding nNOS signaling and the benefits of NO therapies in dystrophinopathies.
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Affiliation(s)
- Stanley C Froehner
- Department of Physiology and Biophysics, University of Washington Medical School, Seattle, WA, USA
| | - Sarah M Reed
- Department of Physiology and Biophysics, University of Washington Medical School, Seattle, WA, USA
| | - Kendra N Anderson
- Department of Physiology and Biophysics, University of Washington Medical School, Seattle, WA, USA
| | - Paul L Huang
- Cardiovascular Research Center and Harvard Stem Cell Institute, Massachusetts General Hospital, Boston, MA, USA and
| | - Justin M Percival
- Department of Physiology and Biophysics, University of Washington Medical School, Seattle, WA, USA Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
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Tidball JG, Wehling-Henricks M. Nitric oxide synthase deficiency and the pathophysiology of muscular dystrophy. J Physiol 2014; 592:4627-38. [PMID: 25194047 DOI: 10.1113/jphysiol.2014.274878] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The secondary loss of neuronal nitric oxide synthase (nNOS) that occurs in dystrophic muscle is the basis of numerous, complex and interacting features of the dystrophic pathology that affect not only muscle itself, but also influence the interaction of muscle with other tissues. Many mechanisms through which nNOS deficiency contributes to misregulation of muscle development, blood flow, fatigue, inflammation and fibrosis in dystrophic muscle have been identified, suggesting that normalization in NO production could greatly attenuate diverse aspects of the pathology of muscular dystrophy through multiple regulatory pathways. However, the relative importance of the loss of nNOS from the sarcolemma versus the importance of loss of total nNOS from dystrophic muscle remains unknown. Although most current evidence indicates that nNOS localization at the sarcolemma is not required to achieve NO-mediated reductions of pathology in muscular dystrophy, the question remains open concerning whether membrane localization would provide a more efficient rescue from features of the dystrophic phenotype.
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Affiliation(s)
- James G Tidball
- Molecular, Cellular & Integrative Physiology Program, University of California, Los Angeles, CA, USA Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, USA Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA, USA
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Cossu MV, Cattaneo D, Fucile S, Pellegrino P, Baldelli S, Cozzi V, Capetti A, Clementi E. Combined isosorbide dinitrate and ibuprofen as a novel therapy for muscular dystrophies: evidence from Phase I studies in healthy volunteers. DRUG DESIGN DEVELOPMENT AND THERAPY 2014; 8:411-9. [PMID: 24851040 PMCID: PMC4018313 DOI: 10.2147/dddt.s58803] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We designed two Phase I studies that assessed healthy volunteers in order to evaluate the safety and to optimize the dosing of the combination of the drugs isosorbide dinitrate, a nitric oxide donor, and ibuprofen, a nonsteroidal antiinflammatory drug. We designed these studies with the aim of designing a Phase II trial to evaluate the drugs’ efficacy in patients affected by Duchenne muscular dystrophy. For the first trial, ISOFEN1, a single-dose, randomized-sequence, open-label, active control, three-treatment cross-over study, was aimed at comparing the pharmacokinetics of ibuprofen 200 mg and isosorbide dinitrate 20 mg when given alone and concomitantly. The pharmacokinetics of ibuprofen given alone versus ibuprofen given concomitantly with isosorbide dinitrate were similar, as documented by the lack of statistically significant differences in the main drug’s pharmacokinetic parameters (time to maximal concentration [Tmax], maximal concentration [Cmax], area under the curve [AUC]0–t, and AUC0–∞). Similarly, we found that the coadministration of ibuprofen did not significantly affect the pharmacokinetics of isosorbide dinitrate. No issues of safety were detected. The second trial, ISOFEN2, was a single-site, dose titration study that was designed to select the maximum tolerated dose for isosorbide dinitrate when coadministered with ibuprofen. Eighteen out of the 19 enrolled subjects tolerated the treatment well, and they completed the study at the highest dose of isosorbide dinitrate applied (80 mg/day). One subject voluntarily decided to reduce the dose of isosorbide dinitrate from 80 mg to 60 mg. The treatment-related adverse events recorded during the study were, for the large majority, episodes of headache that remitted spontaneously in 0.5–1 hour – a known side effect of isosorbide dinitrate. These studies demonstrate that the combination of isosorbide dinitrate and ibuprofen does not lead to pharmacokinetic interactions between the two drugs; they also demonstrate that the combination of isosorbide dinitrate and ibuprofen has optimal tolerability and safety profiles that are similar to those previously reported for isosorbide dinitrate and ibuprofen given alone.
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Affiliation(s)
- Maria Vittoria Cossu
- Unit of Clinical Pharmacology, Consiglio Nazionale delle Ricerche Institute of Neuroscience, Department of Biomedical and Clinical Sciences, University Hospital "Luigi Sacco", Università di Milano, Milan, Italy
| | - Dario Cattaneo
- Unit of Clinical Pharmacology, Consiglio Nazionale delle Ricerche Institute of Neuroscience, Department of Biomedical and Clinical Sciences, University Hospital "Luigi Sacco", Università di Milano, Milan, Italy
| | - Serena Fucile
- Unit of Clinical Pharmacology, Consiglio Nazionale delle Ricerche Institute of Neuroscience, Department of Biomedical and Clinical Sciences, University Hospital "Luigi Sacco", Università di Milano, Milan, Italy
| | - Paolo Pellegrino
- Unit of Clinical Pharmacology, Consiglio Nazionale delle Ricerche Institute of Neuroscience, Department of Biomedical and Clinical Sciences, University Hospital "Luigi Sacco", Università di Milano, Milan, Italy
| | - Sara Baldelli
- Unit of Clinical Pharmacology, Consiglio Nazionale delle Ricerche Institute of Neuroscience, Department of Biomedical and Clinical Sciences, University Hospital "Luigi Sacco", Università di Milano, Milan, Italy
| | - Valeria Cozzi
- Unit of Clinical Pharmacology, Consiglio Nazionale delle Ricerche Institute of Neuroscience, Department of Biomedical and Clinical Sciences, University Hospital "Luigi Sacco", Università di Milano, Milan, Italy
| | - Amedeo Capetti
- Unit of Infectious Diseases, University Hospital "Luigi Sacco", Milan, Italy
| | - Emilio Clementi
- Unit of Clinical Pharmacology, Consiglio Nazionale delle Ricerche Institute of Neuroscience, Department of Biomedical and Clinical Sciences, University Hospital "Luigi Sacco", Università di Milano, Milan, Italy ; Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy
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31
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Abstract
Dystrophin and utrophin are highly similar proteins that both link cortical actin filaments with a complex of sarcolemmal glycoproteins, yet localize to different subcellular domains within normal muscle cells. In mdx mice and Duchenne muscular dystrophy patients, dystrophin is lacking and utrophin is consequently up-regulated and redistributed to locations normally occupied by dystrophin. Transgenic overexpression of utrophin has been shown to significantly improve aspects of the disease phenotype in the mdx mouse; therefore, utrophin up-regulation is under intense investigation as a potential therapy for Duchenne muscular dystrophy. Here we biochemically compared the previously documented microtubule binding activity of dystrophin with utrophin and analyzed several transgenic mouse models to identify phenotypes of the mdx mouse that remain despite transgenic utrophin overexpression. Our in vitro analyses revealed that dystrophin binds microtubules with high affinity and pauses microtubule polymerization, whereas utrophin has no activity in either assay. We also found that transgenic utrophin overexpression does not correct subsarcolemmal microtubule lattice disorganization, loss of torque production after in vivo eccentric contractions, or physical inactivity after mild exercise. Finally, our data suggest that exercise-induced inactivity correlates with loss of sarcolemmal neuronal NOS localization in mdx muscle, whereas loss of in vivo torque production after eccentric contraction-induced injury is associated with microtubule lattice disorganization.
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Thomas MM, Wang DC, D'Souza DM, Krause MP, Layne AS, Criswell DS, O'Neill HM, Connor MK, Anderson JE, Kemp BE, Steinberg GR, Hawke TJ. Muscle-specific AMPK β1β2-null mice display a myopathy due to loss of capillary density in nonpostural muscles. FASEB J 2014; 28:2098-107. [PMID: 24522207 DOI: 10.1096/fj.13-238972] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
AMP-activated protein kinase (AMPK) is a master regulator of metabolism. While muscle-specific AMPK β1β2 double-knockout (β1β2M-KO) mice display alterations in metabolic and mitochondrial capacity, their severe exercise intolerance suggested a secondary contributor to the observed phenotype. We find that tibialis anterior (TA), but not soleus, muscles of sedentary β1β2M-KO mice display a significant myopathy (decreased myofiber areas, increased split and necrotic myofibers, and increased centrally nucleated myofibers. A mitochondrial- and fiber-type-specific etiology to the myopathy was ruled out. However, β1β2M-KO TA muscles displayed significant (P<0.05) increases in platelet aggregation and apoptosis within myofibers and surrounding interstitium (P<0.05). These changes correlated with a 45% decrease in capillary density (P<0.05). We hypothesized that the β1β2M-KO myopathy in resting muscle resulted from impaired AMPK-nNOSμ signaling, causing increased platelet aggregation, impaired vasodilation, and, ultimately, ischemic injury. Consistent with this hypothesis, AMPK-specific phosphorylation (Ser1446) of nNOSμ was decreased in β1β2M-KO compared to wild-type (WT) mice. The AMPK-nNOSμ relationship was further demonstrated by administration of 5-aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR) to β1β2-MKO muscles and C2C12 myotubes. AICAR significantly increased nNOSμ phosphorylation and nitric oxide production (P<0.05) within minutes of administration in WT muscles and C2C12 myotubes but not in β1β2M-KO muscles. These findings highlight the importance of the AMPK-nNOSμ pathway in resting skeletal muscle.
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Affiliation(s)
- Melissa M Thomas
- 2Department of Pathology and Molecular Medicine, McMaster University, 1280 Main St. West, Hamilton, ON L8S4L8, Canada.
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Lawler JM, Kunst M, Hord JM, Lee Y, Joshi K, Botchlett RE, Ramirez A, Martinez DA. EUK-134 ameliorates nNOSμ translocation and skeletal muscle fiber atrophy during short-term mechanical unloading. Am J Physiol Regul Integr Comp Physiol 2014; 306:R470-82. [PMID: 24477538 DOI: 10.1152/ajpregu.00371.2013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Reduced mechanical loading during bedrest, spaceflight, and casting, causes rapid morphological changes in skeletal muscle: fiber atrophy and reduction of slow-twitch fibers. An emerging signaling event in response to unloading is the translocation of neuronal nitric oxide synthase (nNOSμ) from the sarcolemma to the cytosol. We used EUK-134, a cell-permeable mimetic of superoxide dismutase and catalase, to test the role of redox signaling in nNOSμ translocation and muscle fiber atrophy as a result of short-term (54 h) hindlimb unloading. Fischer-344 rats were divided into ambulatory control, hindlimb-unloaded (HU), and hindlimb-unloaded + EUK-134 (HU-EUK) groups. EUK-134 mitigated the unloading-induced phenotype, including muscle fiber atrophy and muscle fiber-type shift from slow to fast. nNOSμ immunolocalization at the sarcolemma of the soleus was reduced with HU, while nNOSμ protein content in the cytosol increased with unloading. Translocation of nNOS from the sarcolemma to cytosol was virtually abolished by EUK-134. EUK-134 also mitigated dephosphorylation at Thr-32 of FoxO3a during HU. Hindlimb unloading elevated oxidative stress (4-hydroxynonenal) and increased sarcolemmal localization of Nox2 subunits gp91phox (Nox2) and p47phox, effects normalized by EUK-134. Thus, our findings are consistent with the hypothesis that oxidative stress triggers nNOSμ translocation from the sarcolemma and FoxO3a dephosphorylation as an early event during mechanical unloading. Thus, redox signaling may serve as a biological switch for nNOS to initiate morphological changes in skeletal muscle fibers.
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Affiliation(s)
- John M Lawler
- Redox Biology and Cell Signaling Laboratory, Department of Health and Kinesiology, Texas A&M University, College Station, Texas
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McDonald FB, Edge D, O'Halloran KD. Chronic nitric oxide synthase inhibition does not impair upper airway muscle adaptation to chronic intermittent hypoxia in the rat. PROGRESS IN BRAIN RESEARCH 2014; 212:237-51. [PMID: 25194201 DOI: 10.1016/b978-0-444-63488-7.00012-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Nitric oxide (NO) is an important modulator of striated muscle function. Nitric oxide synthase (NOS) expression and activity is altered by hypoxia and NO is implicated in respiratory muscle remodeling following chronic sustained hypoxia. We sought to determine if NO is implicated in upper airway dilator muscle adaptation to chronic intermittent hypoxia (CIH). Thirty-two adult male Wistar rats (284±13, mean±SD) were exposed to alternating bouts of hypoxia (90 s; 5% O2 at the nadir) and normoxia (210 s; 21% O2) for 12 cycles per hour, 8h/day for 3 weeks. Sham animals were exposed to normoxia in parallel. Half of the animals in both groups received the nNOS inhibitor-L-NNA (2mM) in the drinking water throughout the study (N=8 for all groups). Sternohyoid (pharyngeal dilator) muscle contractile and endurance properties were determined ex vivo. Sternohyoid muscle myosin heavy chain (MHC) isoform composition and cross-sectional area was determined by fluorescence microscopy. Chronic nNOS blockade did not alter sternohyoid muscle peak force or force-frequency relationship in sham or CIH-treated animals. In contrast, chronic nNOS blockade significantly decreased sternohyoid muscle endurance with equivalent effects in sham and CIH-treated rats. Our results suggest that NO is an important modulator of sternohyoid muscle endurance. However, our data provide no evidence to suggest that NO is implicated in upper airway muscle adaptation to CIH.
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Affiliation(s)
- Fiona B McDonald
- Health Sciences Centre, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Deirdre Edge
- Health Sciences Centre, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland; Department of Physiology, School of Medicine, University College Cork, Cork, Ireland
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, University College Cork, Cork, Ireland.
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35
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Panda SP, Li W, Venkatakrishnan P, Chen L, Astashkin AV, Masters BSS, Feng C, Roman LJ. Differential calmodulin-modulatory and electron transfer properties of neuronal nitric oxide synthase mu compared to the alpha variant. FEBS Lett 2013; 587:3973-8. [PMID: 24211446 DOI: 10.1016/j.febslet.2013.10.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 10/23/2013] [Accepted: 10/24/2013] [Indexed: 10/26/2022]
Abstract
Neuronal nitric oxide synthase μ (nNOSμ) contains 34 additional residues in an autoregulatory element compared to nNOSα. Cytochrome c and flavin reductions in the absence of calmodulin (CaM) were faster in nNOSμ than nNOSα, while rates in the presence of CaM were smaller. The magnitude of stimulation by CaM is thus notably lower in nNOSμ. No difference in NO production was observed, while electron transfer between the FMN and heme moieties and formation of an inhibitory ferrous-nitrosyl complex were slower in nNOSμ. Thus, the insert affects electron transfer rates, modulation of electron flow by CaM, and heme-nitrosyl complex formation.
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Affiliation(s)
- Satya P Panda
- Department of Biochemistry, University of Texas Health Science Center in San Antonio, San Antonio, TX 78229, USA
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37
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Sheffield-Moore M, Wiktorowicz JE, Soman KV, Danesi CP, Kinsky MP, Dillon EL, Randolph KM, Casperson SL, Gore DC, Horstman AM, Lynch JP, Doucet BM, Mettler JA, Ryder JW, Ploutz-Snyder LL, Hsu JW, Jahoor F, Jennings K, White GR, McCammon SD, Durham WJ. Sildenafil increases muscle protein synthesis and reduces muscle fatigue. Clin Transl Sci 2013; 6:463-8. [PMID: 24330691 DOI: 10.1111/cts.12121] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Reductions in skeletal muscle function occur during the course of healthy aging as well as with bed rest or diverse diseases such as cancer, muscular dystrophy, and heart failure. However, there are no accepted pharmacologic therapies to improve impaired skeletal muscle function. Nitric oxide may influence skeletal muscle function through effects on excitation-contraction coupling, myofibrillar function, perfusion, and metabolism. Here we show that augmentation of nitric oxide-cyclic guanosine monophosphate signaling by short-term daily administration of the phosphodiesterase 5 inhibitor sildenafil increases protein synthesis, alters protein expression and nitrosylation, and reduces fatigue in human skeletal muscle. These findings suggest that phosphodiesterase 5 inhibitors represent viable pharmacologic interventions to improve muscle function.
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38
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Janke A, Upadhaya R, Snow WM, Anderson JE. A new look at cytoskeletal NOS-1 and β-dystroglycan changes in developing muscle and brain in control and mdx dystrophic mice. Dev Dyn 2013; 242:1369-81. [PMID: 23940011 DOI: 10.1002/dvdy.24031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 07/17/2013] [Accepted: 07/25/2013] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Loss of dystrophin profoundly affects muscle function and cognition. Changes in the dystrophin-glycoprotein complex (DGC) including disruption of nitric oxide synthase (NOS-1) may result from loss of dystrophin or secondarily after muscle damage. Disruptions in NOS-1 and beta-dystroglycan (bDG) were examined in developing diaphragm, quadriceps, and two brain regions between control and mdx mice at embryonic day E18 and postnatal days P1, P10, and P28. Age-dependent differential muscle loading allowed us to test the hypothesis that DGC changes are dependent on muscle use. RESULTS Muscle development, including loss of central nucleation and the localization of NOS-1 and bDG, was earlier in diaphragm than quadriceps; these features were differentially disrupted in dystrophic muscles. The NOS-1/bDG ratio, an index of DGC stability, was higher in dystrophic diaphragm (P10-P28) and quadriceps (P28) than controls. There were also distinct regional differences in NOS-1 and bDG in brain tissues with age and strain. NOS-1 increased with age in control forebrain and cerebellum, and in mdx cerebellum; NOS-1 and bDG were higher in control than mdx mouse forebrain. CONCLUSIONS Important developmental changes in structure and muscle DGC preceded the hallmarks of dystrophy, and are consistent with the impact of muscle-specific differential loading during maturation.
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Affiliation(s)
- Alyssa Janke
- Faculty of Science, Department of Biological Sciences, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
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Siegel MP, Kruse SE, Percival JM, Goh J, White CC, Hopkins HC, Kavanagh TJ, Szeto HH, Rabinovitch PS, Marcinek DJ. Mitochondrial-targeted peptide rapidly improves mitochondrial energetics and skeletal muscle performance in aged mice. Aging Cell 2013; 12:763-71. [PMID: 23692570 PMCID: PMC3772966 DOI: 10.1111/acel.12102] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2013] [Indexed: 12/25/2022] Open
Abstract
Mitochondrial dysfunction plays a key pathogenic role in aging skeletal muscle resulting in significant healthcare costs in the developed world. However, there is no pharmacologic treatment to rapidly reverse mitochondrial deficits in the elderly. Here, we demonstrate that a single treatment with the mitochondrial-targeted peptide SS-31 restores in vivo mitochondrial energetics to young levels in aged mice after only one hour. Young (5 month old) and old (27 month old) mice were injected intraperitoneally with either saline or 3 mg kg(-1) of SS-31. Skeletal muscle mitochondrial energetics were measured in vivo one hour after injection using a unique combination of optical and (31) P magnetic resonance spectroscopy. Age-related declines in resting and maximal mitochondrial ATP production, coupling of oxidative phosphorylation (P/O), and cell energy state (PCr/ATP) were rapidly reversed after SS-31 treatment, while SS-31 had no observable effect on young muscle. These effects of SS-31 on mitochondrial energetics in aged muscle were also associated with a more reduced glutathione redox status and lower mitochondrial H2 O2 emission. Skeletal muscle of aged mice was more fatigue resistant in situ one hour after SS-31 treatment, and eight days of SS-31 treatment led to increased whole-animal endurance capacity. These data demonstrate that SS-31 represents a new strategy for reversing age-related deficits in skeletal muscle with potential for translation into human use.
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Affiliation(s)
- M. P. Siegel
- Department of Bioengineering, University of Washington, Seattle, WA 98195
| | - S. E. Kruse
- Department of Radiology, University of Washington, Seattle, WA 98195
| | - J. M. Percival
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - J. Goh
- Department of Comparative Medicine, University of Washington, Seattle, WA 98195
- Department of Nutritional Science, University of Washington, Seattle, WA 98195
| | - C. C. White
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195
| | - H. C. Hopkins
- Department of Comparative Medicine, University of Washington, Seattle, WA 98195
| | - T. J. Kavanagh
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195
| | - H. H. Szeto
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10021
| | - P. S. Rabinovitch
- Department of Pathology, University of Washington, Seattle, WA 98195
| | - D. J. Marcinek
- Department of Bioengineering, University of Washington, Seattle, WA 98195
- Department of Radiology, University of Washington, Seattle, WA 98195
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40
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Baum O, Vieregge M, Koch P, Gül S, Hahn S, Huber-Abel FAM, Pries AR, Hoppeler H. Phenotype of capillaries in skeletal muscle of nNOS-knockout mice. Am J Physiol Regul Integr Comp Physiol 2013; 304:R1175-82. [PMID: 23576613 DOI: 10.1152/ajpregu.00434.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Because neuronal nitric oxide synthase (nNOS) has a well-known impact on arteriolar blood flow in skeletal muscle, we compared the ultrastructure and the hemodynamics of/in the ensuing capillaries in the extensor digitorum longus (EDL) muscle of male nNOS-knockout (KO) mice and wild-type (WT) littermates. The capillary-to-fiber (C/F) ratio (-9.1%) was lower (P ≤ 0.05) in the nNOS-KO mice than in the WT mice, whereas the mean cross-sectional fiber area (-7.8%) and the capillary density (-3.1%) varied only nonsignificantly (P > 0.05). Morphometrical estimation of the area occupied by the capillaries as well as the volume and surface densities of the subcellular compartments differed nonsignificantly (P > 0.05) between the two strains. Intravital microscopy revealed neither the capillary diameter (+3% in nNOS-KO mice vs. WT mice) nor the mean velocity of red blood cells in EDL muscle (+25% in nNOS-KO mice vs. WT mice) to significantly vary (P > 0.05) between the two strains. The calculated shear stress in the capillaries was likewise nonsignificantly different (3.8 ± 2.2 dyn/cm² in nNOS-KO mice and 2.1 ± 2.2 dyn/cm² in WT mice; P > 0.05). The mRNA levels of vascular endothelial growth factor (VEGF)-A were lower in the EDL muscle of nNOS-KO mice than in the WT littermates (-37%; P ≤ 0.05), whereas mRNA levels of VEGF receptor-2 (VEGFR-2) (-11%), hypoxia inducible factor-1α (+9%), fibroblast growth factor-2 (-14%), and thrombospondin-1 (-10%) differed nonsignificantly (P > 0.05). Our findings support the contention that VEGF-A mRNA expression and C/F-ratio but not the ultrastructure or the hemodynamics of/in capillaries in skeletal muscle at basal conditions depend on the expression of nNOS.
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Affiliation(s)
- Oliver Baum
- Institute of Anatomy, University of Bern, Bern, Switzerland.
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41
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Meinen S, Lin S, Rüegg MA, Punga AR. Fatigue and muscle atrophy in a mouse model of myasthenia gravis is paralleled by loss of sarcolemmal nNOS. PLoS One 2012; 7:e44148. [PMID: 22952904 PMCID: PMC3429452 DOI: 10.1371/journal.pone.0044148] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 07/30/2012] [Indexed: 02/01/2023] Open
Abstract
Myasthenia Gravis (MG) patients suffer from chronic fatigue of skeletal muscles, even after initiation of proper immunosuppressive medication. Since the localization of neuronal nitric oxide synthase (nNOS) at the muscle membrane is important for sustained muscle contraction, we here study the localization of nNOS in muscles from mice with acetylcholine receptor antibody seropositive (AChR+) experimental autoimmune MG (EAMG). EAMG was induced in 8 week-old male mice by immunization with AChRs purified from torpedo californica. Sham-injected wild type mice and mdx mice, a model for Duchenne muscular dystrophy, were used for comparison. At EAMG disease grade 3 (severe myasthenic weakness), the triceps, sternomastoid and masseter muscles were collected for analysis. Unlike in mdx muscles, total nNOS expression as well as the presence of its binding partner syntrophin α-1, were not altered in EAMG. Immunohistological and biochemical analysis showed that nNOS was lost from the muscle membrane and accumulated in the cytosol, which is likely the consequence of blocked neuromuscular transmission. Atrophy of all examined EAMG muscles were supported by up-regulated transcript levels of the atrogenes atrogin-1 and MuRF1, as well as MuRF1 protein, in combination with reduced muscle fiber diameters. We propose that loss of sarcolemmal nNOS provides an additional mechanism for the chronic muscle fatigue and secondary muscle atrophy in EAMG and MG.
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MESH Headings
- Animals
- Autoantibodies/immunology
- Cytosol/enzymology
- Disease Models, Animal
- Immunization
- Male
- Mice
- Mice, Inbred C57BL
- Models, Biological
- Muscle Denervation
- Muscle Fatigue
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/immunology
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiopathology
- Muscular Atrophy/complications
- Muscular Atrophy/immunology
- Muscular Atrophy/pathology
- Muscular Atrophy/physiopathology
- Myasthenia Gravis, Autoimmune, Experimental/complications
- Myasthenia Gravis, Autoimmune, Experimental/immunology
- Myasthenia Gravis, Autoimmune, Experimental/pathology
- Myasthenia Gravis, Autoimmune, Experimental/physiopathology
- Nitric Oxide Synthase Type I/deficiency
- Nitric Oxide Synthase Type I/genetics
- Nitric Oxide Synthase Type I/metabolism
- Phenotype
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cholinergic/metabolism
- Sarcolemma/enzymology
- Sarcolemma/pathology
- Weight Loss
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Affiliation(s)
- Sarina Meinen
- Department of Neurobiology/Pharmacology, Biozentrum, University of Basel, Basel, Switzerland
| | - Shuo Lin
- Department of Neurobiology/Pharmacology, Biozentrum, University of Basel, Basel, Switzerland
| | - Markus A. Rüegg
- Department of Neurobiology/Pharmacology, Biozentrum, University of Basel, Basel, Switzerland
| | - Anna Rostedt Punga
- Department of Neurobiology/Pharmacology, Biozentrum, University of Basel, Basel, Switzerland
- * E-mail:
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42
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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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Percival JM, Whitehead NP, Adams ME, Adamo CM, Beavo JA, Froehner SC. Sildenafil reduces respiratory muscle weakness and fibrosis in the mdx mouse model of Duchenne muscular dystrophy. J Pathol 2012; 228:77-87. [PMID: 22653783 DOI: 10.1002/path.4054] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 05/16/2010] [Accepted: 05/21/2010] [Indexed: 11/07/2022]
Abstract
Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy caused by mutations in the dystrophin gene. Loss of dystrophin initiates a progressive decline in skeletal muscle integrity and contractile capacity which weakens respiratory muscles including the diaphragm, culminating in respiratory failure, the leading cause of morbidity and mortality in DMD patients. At present, corticosteroid treatment is the primary pharmacological intervention in DMD, but has limited efficacy and adverse side effects. Thus, there is an urgent need for new safe, cost-effective, and rapidly implementable treatments that slow disease progression. One promising new approach is the amplification of nitric oxide-cyclic guanosine monophosphate (NO-cGMP) signalling pathways with phosphodiesterase 5 (PDE5) inhibitors. PDE5 inhibitors serve to amplify NO signalling that is attenuated in many neuromuscular diseases including DMD. We report here that a 14-week treatment of the mdx mouse model of DMD with the PDE5 inhibitor sildenafil (Viagra(®), Revatio(®)) significantly reduced mdx diaphragm muscle weakness without impacting fatigue resistance. In addition to enhancing respiratory muscle contractility, sildenafil also promoted normal extracellular matrix organization. PDE5 inhibition slowed the establishment of mdx diaphragm fibrosis and reduced matrix metalloproteinase-13 (MMP-13) expression. Sildenafil also normalized the expression of the pro-fibrotic (and pro-inflammatory) cytokine tumour necrosis factor α (TNFα). Sildenafil-treated mdx diaphragms accumulated significantly less Evans Blue tracer dye than untreated controls, which is also indicative of improved diaphragm muscle health. We conclude that sildenafil-mediated PDE5 inhibition significantly reduces diaphragm respiratory muscle dysfunction and pathology in the mdx mouse model of Duchenne muscular dystrophy. This study provides new insights into the therapeutic utility of targeting defects in NO-cGMP signalling with PDE5 inhibitors in dystrophin-deficient muscle.
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Affiliation(s)
- Justin M Percival
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA.
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44
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Kim JH, Lawler JM. Amplification of proinflammatory phenotype, damage, and weakness by oxidative stress in the diaphragm muscle of mdx mice. Free Radic Biol Med 2012; 52:1597-606. [PMID: 22330042 DOI: 10.1016/j.freeradbiomed.2012.01.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2011] [Revised: 01/10/2012] [Accepted: 01/20/2012] [Indexed: 12/27/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a common and devastating type of childhood-onset muscular dystrophy, attributed to an X-linked defect in the gene that encodes dystrophin. Myopathy with DMD is most pronounced in the diaphragm muscle and fast-twitch limb muscles and is dependent upon susceptibility to damage, inflammatory cell infiltration, and proinflammatory signaling (nuclear factor-κB; NF-κB). Although recent papers have reawakened the notion that oxidative stress links inflammatory signaling with pathology in DMD in limb muscle, the importance of redox mechanisms had been clouded by inconsistent results from indirect scavenger approaches, including in the diaphragm muscle. Therefore, we used a novel catalytic mimetic of superoxide dismutase and catalase (EUK-134) as a direct scavenger of oxidative stress in myopathy in the diaphragm of the mdx mouse model. EUK-134 reduced 4-hydroxynonenal and total hydroperoxides, markers of oxidative stress in the mdx diaphragm. EUK-134 also attenuated positive staining of macrophages and T-cells as well as activation of NF-κB and p65 protein abundance. Moreover, EUK-134 ameliorated markers of muscle damage including internalized nuclei, variability of cross-sectional area, and type IIc fibers. Finally, impairment of contractile force was partially rescued by EUK-134 in the diaphragm of mdx mice. We conclude that oxidative stress amplifies DMD pathology in the diaphragm muscle.
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Affiliation(s)
- Jong-Hee Kim
- Redox Biology and Cell Signaling Laboratory, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843-4243, USA
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45
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Radak Z, Naito H, Taylor AW, Goto S. Nitric oxide: Is it the cause of muscle soreness? Nitric Oxide 2012; 26:89-94. [DOI: 10.1016/j.niox.2011.12.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 12/14/2011] [Accepted: 12/21/2011] [Indexed: 11/25/2022]
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46
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Kobayashi YM, Rader EP, Crawford RW, Campbell KP. Endpoint measures in the mdx mouse relevant for muscular dystrophy pre-clinical studies. Neuromuscul Disord 2011; 22:34-42. [PMID: 22154712 DOI: 10.1016/j.nmd.2011.08.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 07/20/2011] [Accepted: 08/01/2011] [Indexed: 12/01/2022]
Abstract
Loss of mobility influences the quality of life for patients with neuromuscular diseases. Common measures of mobility and chronic muscle damage are the six-minute walk test and serum creatine kinase. Despite extensive pre-clinical studies of therapeutic approaches, characterization of these measures is incomplete. To address this, a six-minute ambulation assay, serum creatine kinase, and myoglobinuria were investigated for the mdx mouse, a dystrophinopathy mouse model commonly used in pre-clinical studies. mdx mice ambulated shorter distances than normal controls, a disparity accentuated after mild exercise. An asymmetric pathophysiology in mdx mice was unmasked with exercise, and peak measurements of serum creatine kinase and myoglobinuria were identified. Our data highlights the necessity to consider asymmetric pathology and timing of biomarkers when testing potential therapies for muscular dystrophy.
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Affiliation(s)
- Yvonne M Kobayashi
- Department of Molecular Physiology and Biophysics, Howard Hughes Medical Institute, University of Iowa Roy J. and Lucille A. Carver College of Medicine, City, IA 52242-1101, USA
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47
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nNOS regulation of skeletal muscle fatigue and exercise performance. Biophys Rev 2011; 3:209-217. [PMID: 28510048 DOI: 10.1007/s12551-011-0060-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 10/17/2011] [Indexed: 10/15/2022] Open
Abstract
Neuronal nitric oxide synthases (nNOS) are Ca2+/calmodulin-activated enzymes that synthesize the gaseous messenger nitric oxide (NO). nNOSμ and the recently described nNOSβ, both spliced nNOS isoforms, are important enzymatic sources of NO in skeletal muscle, a tissue long considered to be a paradigmatic system for studying NO-dependent redox signaling. nNOS is indispensable for skeletal muscle integrity and contractile performance, and deregulation of nNOSμ signaling is a common pathogenic feature of many neuromuscular diseases. Recent evidence suggests that both nNOSμ and nNOSβ regulate skeletal muscle size, strength, and fatigue resistance, making them important players in exercise performance. nNOSμ acts as an activity sensor and appears to assist skeletal muscle adaptation to new functional demands, particularly those of endurance exercise. Prolonged inactivity leads to nNOS-mediated muscle atrophy through a FoxO-dependent pathway. nNOS also plays a role in modulating exercise performance in neuromuscular disease. In the mdx mouse model of Duchenne muscular dystrophy, defective nNOS signaling is thought to restrict contractile capacity of working muscle in two ways: loss of sarcolemmal nNOSμ causes excessive ischemic damage while residual cytosolic nNOSμ contributes to hypernitrosylation of the ryanodine receptor, causing pathogenic Ca2+ leak. This defect in Ca2+ handling promotes muscle damage, weakness, and fatigue. This review addresses these recent advances in the understanding of nNOS-dependent redox regulation of skeletal muscle function and exercise performance under physiological and neuromuscular disease conditions.
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Wehling-Henricks M, Tidball JG. Neuronal nitric oxide synthase-rescue of dystrophin/utrophin double knockout mice does not require nNOS localization to the cell membrane. PLoS One 2011; 6:e25071. [PMID: 22003386 PMCID: PMC3189177 DOI: 10.1371/journal.pone.0025071] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 08/26/2011] [Indexed: 02/03/2023] Open
Abstract
Survival of dystrophin/utrophin double-knockout (dko) mice was increased by muscle-specific expression of a neuronal nitric oxide synthase (nNOS) transgene. Dko mice expressing the transgene (nNOS TG+/dko) experienced delayed onset of mortality and increased life-span. The nNOS TG+/dko mice demonstrated a significant decrease in the concentration of CD163+, M2c macrophages that can express arginase and promote fibrosis. The decrease in M2c macrophages was associated with a significant reduction in fibrosis of heart, diaphragm and hindlimb muscles of nNOS TG+/dko mice. The nNOS transgene had no effect on the concentration of cytolytic, CD68+, M1 macrophages. Accordingly, we did not observe any change in the extent of muscle fiber lysis in the nNOS TG+/dko mice. These findings show that nNOS/NO (nitric oxide)-mediated decreases in M2c macrophages lead to a reduction in the muscle fibrosis that is associated with increased mortality in mice lacking dystrophin and utrophin. Interestingly, the dramatic and beneficial effects of the nNOS transgene were not attributable to localization of nNOS protein at the cell membrane. We did not detect any nNOS protein at the sarcolemma in nNOS TG+/dko muscles. This important observation shows that sarcolemmal localization is not necessary for nNOS to have beneficial effects in dystrophic tissue and the presence of nNOS in the cytosol of dystrophic muscle fibers can ameliorate the pathology and most importantly, significantly increase life-span.
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Affiliation(s)
- Michelle Wehling-Henricks
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California, United States of America
| | - James G. Tidball
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California, United States of America
- Molecular, Cellular and Integrative Physiology Program, University of California, Los Angeles, California, United States of America
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
- * E-mail:
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Church JE, Gehrig SM, Chee A, Naim T, Trieu J, McConell GK, Lynch GS. Early functional muscle regeneration after myotoxic injury in mice is unaffected by nNOS absence. Am J Physiol Regul Integr Comp Physiol 2011; 301:R1358-66. [PMID: 21849632 DOI: 10.1152/ajpregu.00096.2011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nitric oxide (NO) is an important signaling molecule produced in skeletal muscle primarily via the neuronal subtype of NO synthase (NOS1, or nNOS). While many studies have reported NO production to be important in muscle regeneration, none have examined the contribution of nNOS-derived NO to functional muscle regeneration (i.e., restoration of the muscle's ability to produce force) after acute myotoxic injury. In the present study, we tested the hypothesis that genetic deletion of nNOS would impair functional muscle regeneration after myotoxic injury in nNOS(-/-) mice. We found that nNOS(-/-) mice had lower body mass, lower muscle mass, and smaller myofiber cross-sectional area and that their tibialis anterior (TA) muscles produced lower absolute tetanic forces than those of wild-type littermate controls but that normalized or specific force was identical between the strains. In addition, muscles from nNOS(-/-) mice were more resistant to fatigue than those of wild-type littermates (P < 0.05). To determine whether deletion of nNOS affected muscle regeneration, TA muscles from nNOS(-/-) mice and wild-type littermates were injected with the myotoxin notexin to cause complete fiber degeneration, and muscle structure and function were assessed at 7 and 10 days postinjury. Myofiber cross-sectional area was lower in regenerating nNOS(-/-) mice than wild-type controls at 7 and 10 days postinjury; however, contrary to our original hypothesis, no difference in force-producing capacity of the TA muscle was evident between the two groups at either time point. Our findings reveal that nNOS is not essential for functional muscle regeneration after acute myotoxic damage.
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Affiliation(s)
- Jarrod E Church
- Basic and Clinical Myology Laboratory, Department of Physiology, The University of Melbourne, Melbourne, Victoria, Australia
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Lawler JM. Exacerbation of pathology by oxidative stress in respiratory and locomotor muscles with Duchenne muscular dystrophy. J Physiol 2011; 589:2161-70. [PMID: 21486793 PMCID: PMC3098695 DOI: 10.1113/jphysiol.2011.207456] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2011] [Accepted: 03/02/2011] [Indexed: 12/15/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is the most devastating type of muscular dystrophy, leading to progressive weakness of respiratory (e.g. diaphragm) and locomotor muscles (e.g. gastrocnemius). DMD is caused by X-linked defects in the gene that encodes for dystrophin, a key scaffolding protein of the dystroglycan complex (DCG) within the sarcolemmal cytoskeleton. As a result of a compromised dystroglycan complex, mechanical integrity is impaired and important signalling proteins (e.g. nNOS, caveolin-3) and pathways are disrupted. Disruption of the dystroglycan complex leads to high susceptibility to injury with repeated, eccentric contractions as well as inflammation, resulting in significant damage and necrosis. Chronic damage and repair cycling leads to fibrosis and weakness. While the link between inflammation with damage and weakness in the DMD diaphragm is unresolved, elevated oxidative stress may contribute to damage, weakness and possibly fibrosis. While utilization of non-specific antioxidant interventions has yielded inconsistent results, recent data suggest that NAD(P)H oxidase could play a pivotal role in elevating oxidative stress via integrated changes in caveolin-3 and stretch-activated channels (SACs). Oxidative stress may act as an amplifier, exacerbating disruption of the dystroglycan complex, upregulation of the inflammatory transcription factor NF-B, and thus functional impairment of force-generating capacity.
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Affiliation(s)
- John M Lawler
- Department of Health and Kinesiology, Texas A&M University, College Station, TX 77843-4243, USA.
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