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Krishna L, Prashant A, Kumar YH, Paneyala S, Patil SJ, Ramachandra SC, Vishwanath P. Molecular and Biochemical Therapeutic Strategies for Duchenne Muscular Dystrophy. Neurol Int 2024; 16:731-760. [PMID: 39051216 PMCID: PMC11270304 DOI: 10.3390/neurolint16040055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 06/24/2024] [Accepted: 07/03/2024] [Indexed: 07/27/2024] Open
Abstract
Significant progress has been achieved in understanding Duchenne muscular dystrophy (DMD) mechanisms and developing treatments to slow disease progression. This review article thoroughly assesses primary and secondary DMD therapies, focusing on innovative modalities. The primary therapy addresses the genetic abnormality causing DMD, specifically the absence or reduced expression of dystrophin. Gene replacement therapies, such as exon skipping, readthrough, and gene editing technologies, show promise in restoring dystrophin expression. Adeno-associated viruses (AAVs), a recent advancement in viral vector-based gene therapies, have shown encouraging results in preclinical and clinical studies. Secondary therapies aim to maintain muscle function and improve quality of life by mitigating DMD symptoms and complications. Glucocorticoid drugs like prednisone and deflazacort have proven effective in slowing disease progression and delaying loss of ambulation. Supportive treatments targeting calcium dysregulation, histone deacetylase, and redox imbalance are also crucial for preserving overall health and function. Additionally, the review includes a detailed table of ongoing and approved clinical trials for DMD, exploring various therapeutic approaches such as gene therapies, exon skipping drugs, utrophin modulators, anti-inflammatory agents, and novel compounds. This highlights the dynamic research field and ongoing efforts to develop effective DMD treatments.
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Affiliation(s)
- Lakshmi Krishna
- Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India; (L.K.); (A.P.); (S.C.R.)
| | - Akila Prashant
- Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India; (L.K.); (A.P.); (S.C.R.)
- Department of Medical Genetics, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India
| | - Yogish H. Kumar
- Department of Pharmaceutical Chemistry, JSS College of Pharmacy, Mysuru, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India;
| | - Shasthara Paneyala
- Department of Neurology, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India;
| | - Siddaramappa J. Patil
- Department of Medical Genetics, Narayana Hrudalaya Health Hospital/Mazumdar Shah, Bengaluru 560099, Karnataka, India;
| | - Shobha Chikkavaddaragudi Ramachandra
- Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India; (L.K.); (A.P.); (S.C.R.)
| | - Prashant Vishwanath
- Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, Karnataka, India; (L.K.); (A.P.); (S.C.R.)
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Phosphodiesterase 5a Signalling in Skeletal Muscle Pathophysiology. Int J Mol Sci 2022; 24:ijms24010703. [PMID: 36614143 PMCID: PMC9820699 DOI: 10.3390/ijms24010703] [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: 11/18/2022] [Revised: 12/20/2022] [Accepted: 12/27/2022] [Indexed: 01/03/2023] Open
Abstract
Phosphodiesterase 5A (PDE5A) is involved in cGMP hydrolysis, regulating many physiological processes. Increased activity of PDE5A has been found in several pathological conditions, and the pharmacological inhibition of PDE5 has been demonstrated to have several therapeutic applications. We have identified the presence of three different Pde5a isoforms in cardiomyocytes, and we have found that the expression of specific Pde5a isoforms may have a causal role in the onset of pathological responses in these cells. In our previous study, we demonstrated that PDE5A inhibition could ameliorate muscular dystrophy by acting at different levels, as assessed by the altered genomic response of muscular cells following treatment with the PDE5A inhibitor tadalafil. Thus, considering the importance of PDE5A in various pathophysiological conditions, we further investigated the regulation of this enzyme. Here, we analysed the expression of Pde5a isoforms in the pathophysiology of skeletal muscle. We found that skeletal muscle tissues and myogenic cells express Pde5a1 and Pde5a2 isoforms, and we observed an increased expression of Pde5a1 in damaged skeletal muscles, while Pde5a2 levels remained unchanged. We also cloned and characterized the promoters that control the transcription of Pde5a isoforms, investigating which of the transcription factors predicted by bioinformatics analysis could be involved in their modulation. In conclusion, we found an overexpression of Pde5a1 in compromised muscle and identified an involvement of MyoD and Runx1 in Pde5a1 transcriptional activity.
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Yao S, Chen Z, Yu Y, Zhang N, Jiang H, Zhang G, Zhang Z, Zhang B. Current Pharmacological Strategies for Duchenne Muscular Dystrophy. Front Cell Dev Biol 2021; 9:689533. [PMID: 34490244 PMCID: PMC8417245 DOI: 10.3389/fcell.2021.689533] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 07/23/2021] [Indexed: 12/25/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a lethal, X-linked neuromuscular disorder caused by the absence of dystrophin protein, which is essential for muscle fiber integrity. Loss of dystrophin protein leads to recurrent myofiber damage, chronic inflammation, progressive fibrosis, and dysfunction of muscle stem cells. There is still no cure for DMD so far and the standard of care is principally limited to symptom relief through glucocorticoids treatments. Current therapeutic strategies could be divided into two lines. Dystrophin-targeted therapeutic strategies that aim at restoring the expression and/or function of dystrophin, including gene-based, cell-based and protein replacement therapies. The other line of therapeutic strategies aims to improve muscle function and quality by targeting the downstream pathological changes, including inflammation, fibrosis, and muscle atrophy. This review introduces the important developments in these two lines of strategies, especially those that have entered the clinical phase and/or have great potential for clinical translation. The rationale and efficacy of each agent in pre-clinical or clinical studies are presented. Furthermore, a meta-analysis of gene profiling in DMD patients has been performed to understand the molecular mechanisms of DMD.
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Affiliation(s)
- Shanshan Yao
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Zihao Chen
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Yuanyuan Yu
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong
| | - Ning Zhang
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Hewen Jiang
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Ge Zhang
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong
| | - Zongkang Zhang
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Baoting Zhang
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
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Dudley RWR, Comtois AS, St-Pierre DH, Danialou G. Early administration of L-arginine in mdx neonatal mice delays the onset of muscular dystrophy in tibialis anterior (TA) muscle. FASEB Bioadv 2021; 3:639-651. [PMID: 34377959 PMCID: PMC8332474 DOI: 10.1096/fba.2020-00104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 02/17/2021] [Accepted: 04/15/2021] [Indexed: 12/04/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a genetic disorder that results in the absence of dystrophin, a cytoskeletal protein. Individuals with this disease experience progressive muscle destruction, which leads to muscle weakness. Studies have been conducted to find solutions for the relief of individuals with this disease, several of which have shown that utrophin, a protein closely related to dystrophin, when overexpressed in mdx neonatal mice (the murine model of DMD), is able to prevent the progressive muscle destruction observed in the absence of dystrophin. Furthermore, recent studies have shown that L‐arginine induces utrophin upregulation in adult mdx mice. We hypothesized that L‐arginine treatment also induces utrophin upregulation to prevent the development of muscle weakness in neonatal mdx mice. Hence, L‐arginine should also prevent progressive muscle destruction via utrophin upregulation in mdx neonatal mice. Mdx neonatal mice were injected intraperitoneally daily with 800 mg/kg of L‐arginine for 6 weeks, whereas control mice were injected with a physiological saline. The following experiments were performed on the tibialis anterior (TA) muscle: muscle contractility and resistance to mechanical stress; central nucleation and peripheral nucleation, utrophin, and creatine kinase quantification as well as a nitric oxide (NO) assay. Our findings show that early administration of L‐arginine in mdx neonatal mice prevents the destruction of the tibialis anterior (TA) muscle. However, this improvement was related to nitric oxide (NO) production rather than the expected utrophin upregulation.
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Affiliation(s)
- Roy W R Dudley
- Meakins Christie Laboratories McGill University Montreal QC Canada
| | - Alain S Comtois
- Département des Sciences de l'Activité Physique Université du Québec à Montréal (UQAM Montreal QC Canada.,Groupe de Recherche en Activité Physique Adaptée UQAM Montreal QC Canada
| | - David H St-Pierre
- Département des Sciences de l'Activité Physique Université du Québec à Montréal (UQAM Montreal QC Canada.,Groupe de Recherche en Activité Physique Adaptée UQAM Montreal QC Canada.,Centre de Recherche du CHU Sainte-Justine Montréal QC Canada
| | - Gawiyou Danialou
- Meakins Christie Laboratories McGill University Montreal QC Canada.,Département des Sciences de l'Activité Physique Université du Québec à Montréal (UQAM Montreal QC Canada.,Royal Military College Saint-Jean Saint-Jean-sur-Richelieu QC Canada
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Lambert MR, Spinazzola JM, Widrick JJ, Pakula A, Conner JR, Chin JE, Owens JM, Kunkel LM. PDE10A Inhibition Reduces the Manifestation of Pathology in DMD Zebrafish and Represses the Genetic Modifier PITPNA. Mol Ther 2020; 29:1086-1101. [PMID: 33221436 PMCID: PMC7934586 DOI: 10.1016/j.ymthe.2020.11.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/04/2020] [Accepted: 11/15/2020] [Indexed: 12/25/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe genetic disorder caused by mutations in the DMD gene. Absence of dystrophin protein leads to progressive degradation of skeletal and cardiac function and leads to premature death. Over the years, zebrafish have been increasingly used for studying DMD and are a powerful tool for drug discovery and therapeutic development. In our study, a birefringence screening assay led to identification of phosphodiesterase 10A (PDE10A) inhibitors that reduced the manifestation of dystrophic muscle phenotype in dystrophin-deficient sapje-like zebrafish larvae. PDE10A has been validated as a therapeutic target by pde10a morpholino-mediated reduction in muscle pathology and improvement in locomotion, muscle, and vascular function as well as long-term survival in sapje-like larvae. PDE10A inhibition in zebrafish and DMD patient-derived myoblasts were also associated with reduction of PITPNA expression that has been previously identified as a protective genetic modifier in two exceptional dystrophin-deficient golden retriever muscular dystrophy (GRMD) dogs that escaped the dystrophic phenotype. The combination of a phenotypic assay and relevant functional assessments in the sapje-like zebrafish enhances the potential for the prospective discovery of DMD therapeutics. Indeed, our results suggest a new application for a PDE10A inhibitor as a potential DMD therapeutic to be investigated in a mouse model of DMD.
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Affiliation(s)
- Matthias R Lambert
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Janelle M Spinazzola
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Jeffrey J Widrick
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Anna Pakula
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - James R Conner
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Janice E Chin
- Rare Disease Research Unit, Pfizer, Cambridge, MA 02139, USA
| | - Jane M Owens
- Rare Disease Research Unit, Pfizer, Cambridge, MA 02139, USA
| | - Louis M Kunkel
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; The Stem Cell Program, Boston Children's Hospital, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA; The Manton Center for Orphan Disease Research at Boston Children's Hospital, Boston, MA 02115, USA.
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Cocksedge SP, Breese BC, Morgan PT, Nogueira L, Thompson C, Wylie LJ, Jones AM, Bailey SJ. Influence of muscle oxygenation and nitrate-rich beetroot juice supplementation on O 2 uptake kinetics and exercise tolerance. Nitric Oxide 2020; 99:25-33. [PMID: 32272260 DOI: 10.1016/j.niox.2020.03.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 11/25/2022]
Abstract
We tested the hypothesis that acute supplementation with nitrate (NO3-)-rich beetroot juice (BR) would improve quadriceps muscle oxygenation, pulmonary oxygen uptake (V˙O2) kinetics and exercise tolerance (Tlim) in normoxia and that these improvements would be augmented in hypoxia and attenuated in hyperoxia. In a randomised, double-blind, cross-over study, ten healthy males completed two-step cycle tests to Tlim following acute consumption of 210 mL BR (18.6 mmol NO3-) or NO3--depleted beetroot juice placebo (PL; 0.12 mmol NO3-). These tests were completed in normobaric normoxia [fraction of inspired oxygen (FIO2): 21%], hypoxia (FIO2: 15%) and hyperoxia (FIO2: 40%). Pulmonary V˙O2 and quadriceps tissue oxygenation index (TOI), derived from multi-channel near-infrared spectroscopy, were measured during all trials. Plasma [nitrite] was higher in all BR compared to all PL trials (P < 0.05). Quadriceps TOI was higher in normoxia compared to hypoxia (P < 0.05) and higher in hyperoxia compared to hypoxia and normoxia (P < 0.05). Tlim was improved after BR compared to PL ingestion in the hypoxic trials (250 ± 44 vs. 231 ± 41 s; P = 0.006; d = 1.13), with the magnitude of improvement being negatively correlated with quadriceps TOI at Tlim (r = -0.78; P < 0.05). Tlim was not improved following BR ingestion in normoxia (BR: 364 ± 98 vs. PL: 344 ± 78 s; P = 0.087, d = 0.61) or hyperoxia (BR: 492 ± 212 vs. PL: 472 ± 196 s; P = 0.273, d = 0.37). BR ingestion increased peak V˙O2 in hypoxia (P < 0.05), but not normoxia or hyperoxia (P > 0.05). These findings indicate that BR supplementation is more likely to improve Tlim and peak V˙O2 in situations when skeletal muscle is more hypoxic.
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Affiliation(s)
- Stuart P Cocksedge
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Heavitree Road, Exeter, UK; School of Sport, Exercise and Health Sciences, Loughborough University, Epinal Way, Loughborough, UK
| | - Brynmor C Breese
- School of Biological and Biomedical Sciences, Portland Square Building, Plymouth University, Drake Circus, Plymouth, UK
| | - Paul T Morgan
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Heavitree Road, Exeter, UK
| | - Leonardo Nogueira
- Section of Physiology, Division of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of California, San Diego, CA, USA; Instituto de Bioquímica Médica Leopoldo de Meis (Medical Biochemistry Institute Leopoldo de Meis), Federal University of Rio de Janeiro, RJ, Brazil
| | - Christopher Thompson
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Heavitree Road, Exeter, UK
| | - Lee J Wylie
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Heavitree Road, Exeter, UK
| | - Andrew M Jones
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Heavitree Road, Exeter, UK
| | - Stephen J Bailey
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Heavitree Road, Exeter, UK; School of Sport, Exercise and Health Sciences, Loughborough University, Epinal Way, Loughborough, UK.
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Batra A, Vohra RS, Chrzanowski SM, Hammers DW, Lott DJ, Vandenborne K, Walter GA, Forbes SC. Effects of PDE5 inhibition on dystrophic muscle following an acute bout of downhill running and endurance training. J Appl Physiol (1985) 2019; 126:1737-1745. [PMID: 30946638 DOI: 10.1152/japplphysiol.00664.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lack of sarcolemma-localized neuronal nitric oxide synthase mu (nNOSμ) contributes to muscle damage and fatigue in dystrophic muscle. In this study, we examined the effects of compensating for lack of nNOSμ with a phosphodiesterase type 5 (PDE5) inhibitor in mdx mice following downhill running and endurance training. Dystrophic mice (mdx) were treated with sildenafil citrate and compared with untreated mdx and wild-type mice after an acute bout of downhill running and during a progressive low-intensity treadmill running program (5 days/wk, 4 wk). Magnetic resonance imaging (MRI) and spectroscopy (MRS) transverse relaxation time constant (T2) of hindlimb and forelimb muscles were measured as a marker of muscle damage after downhill running and throughout training. The MRI blood oxygenation level dependence (BOLD) response and 31phosphorus MRS (31P-MRS) data were acquired after stimulated muscle contractions. After downhill running, the increase in T2 was attenuated (P < 0.05) in treated mdx and wild-type mice compared with untreated mdx. During training, resting T2 values did not change in wild-type and mdx mice from baseline values; however, the running distance completed during training was greater (P < 0.05) in treated mdx (>90% of target distance) and wild-type (100%) than untreated mdx (60%). The post-contractile BOLD response was greater (P < 0.05) in treated mdx that trained than untreated mdx, with no differences in muscle oxidative capacity, as measured by 31P-MRS. Our findings indicate that PDE5 inhibition reduces muscle damage after a single bout of downhill running and improves performance during endurance training in dystrophic mice, possibly because of enhanced microvascular function. NEW & NOTEWORTHY This study examined the combined effects of PDE5 inhibition and exercise in dystrophic muscle using high-resolution magnetic resonance imaging and spectroscopy. Our findings demonstrated that sildenafil citrate reduces muscle damage after a single bout of downhill running, improves endurance-training performance, and enhances microvascular function in dystrophic muscle. Collectively, the results support the combination of exercise and PDE5 inhibition as a therapeutic approach in muscular dystrophies lacking nNOSμ.
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Affiliation(s)
- Abhinandan Batra
- Department of Physical Therapy, University of Florida , Gainesville, Florida
| | - Ravneet S Vohra
- Department of Physical Therapy, University of Florida , Gainesville, Florida
| | - Steve M Chrzanowski
- Department of Physiology and Therapeutics, University of Florida , Gainesville, Florida
| | - David W Hammers
- Department of Pharmacology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Donovan J Lott
- Department of Physical Therapy, University of Florida , Gainesville, Florida
| | - Krista Vandenborne
- Department of Physical Therapy, University of Florida , Gainesville, Florida
| | - Glenn A Walter
- Department of Physiology and Therapeutics, University of Florida , Gainesville, Florida
| | - Sean C Forbes
- Department of Physical Therapy, University of Florida , Gainesville, Florida
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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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Nutrition in Duchenne muscular dystrophy 16–18 March 2018, Zaandam, the Netherlands. Neuromuscul Disord 2018; 28:680-689. [DOI: 10.1016/j.nmd.2018.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 05/09/2018] [Indexed: 11/17/2022]
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Transient receptor potential channel 6 regulates abnormal cardiac S-nitrosylation in Duchenne muscular dystrophy. Proc Natl Acad Sci U S A 2017; 114:E10763-E10771. [PMID: 29187535 DOI: 10.1073/pnas.1712623114] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked disorder with dystrophin loss that results in skeletal and cardiac muscle weakening and early death. Loss of the dystrophin-sarcoglycan complex delocalizes nitric oxide synthase (NOS) to alter its signaling, and augments mechanosensitive intracellular Ca2+ influx. The latter has been coupled to hyperactivation of the nonselective cation channel, transient receptor potential canonical channel 6 (Trpc6), in isolated myocytes. As Ca2+ also activates NOS, we hypothesized that Trpc6 would help to mediate nitric oxide (NO) dysregulation and that this would be manifest in increased myocardial S-nitrosylation, a posttranslational modification increasingly implicated in neurodegenerative, inflammatory, and muscle disease. Using a recently developed dual-labeling proteomic strategy, we identified 1,276 S-nitrosylated cysteine residues [S-nitrosothiol (SNO)] on 491 proteins in resting hearts from a mouse model of DMD (dmdmdx:utrn+/-). These largely consisted of mitochondrial proteins, metabolic regulators, and sarcomeric proteins, with 80% of them also modified in wild type (WT). S-nitrosylation levels, however, were increased in DMD. Genetic deletion of Trpc6 in this model (dmdmdx:utrn+/-:trpc6-/-) reversed ∼70% of these changes. Trpc6 deletion also ameliorated left ventricular dilation, improved cardiac function, and tended to reduce fibrosis. Furthermore, under catecholamine stimulation, which also increases NO synthesis and intracellular Ca2+ along with cardiac workload, the hypernitrosylated state remained as it did at baseline. However, the impact of Trpc6 deletion on the SNO proteome became less marked. These findings reveal a role for Trpc6-mediated hypernitrosylation in dmdmdx:utrn+/- mice and support accumulating evidence that implicates nitrosative stress in cardiac and muscle disease.
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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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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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Abstract
Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy in childhood. It is caused by mutations of the DMD gene, leading to progressive muscle weakness, loss of independent ambulation by early teens, and premature death due to cardiorespiratory complications. The diagnosis can usually be made after careful review of the history and examination of affected boys presenting with developmental delay, proximal weakness, and elevated serum creatine kinase, plus confirmation by muscle biopsy or genetic testing. Precise characterization of the DMD mutation is important for genetic counseling and individualized treatment. Current standard of care includes the use of corticosteroids to prolong ambulation and to delay the onset of secondary complications. Early use of cardioprotective agents, noninvasive positive pressure ventilation, and other supportive strategies has improved the life expectancy and health-related quality of life for many young adults with DMD. New emerging treatment includes viral-mediated microdystrophin gene replacement, exon skipping to restore the reading frame, and nonsense suppression therapy to allow translation and production of a modified dystrophin protein. Other potential therapeutic targets involve upregulation of compensatory proteins, reduction of the inflammatory cascade, and enhancement of muscle regeneration. So far, data from DMD clinical trials have shown limited success in delaying disease progression; unforeseen obstacles included immune response against the generated mini-dystrophin, inconsistent evidence of dystrophin production in muscle biopsies, and failure to demonstrate a significant improvement in the primary outcome measure, as defined by the 6-minute walk test in some studies. The long-term safety and efficacy of emerging treatments will depend on the selection of appropriate clinical end points and sensitive biomarkers to detect meaningful changes in disease progression. Correction of the underlying mutations using new gene-editing technologies and corticosteroid analogs with better safety profiles offers renewed hope for many individuals with DMD and their families.
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Affiliation(s)
- Jean K Mah
- Department of Pediatrics and Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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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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15
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De Arcangelis V, Strimpakos G, Gabanella F, Corbi N, Luvisetto S, Magrelli A, Onori A, Passananti C, Pisani C, Rome S, Severini C, Naro F, Mattei E, Di Certo MG, Monaco L. Pathways Implicated in Tadalafil Amelioration of Duchenne Muscular Dystrophy. J Cell Physiol 2016; 231:224-32. [PMID: 26097015 DOI: 10.1002/jcp.25075] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/08/2015] [Indexed: 12/15/2022]
Abstract
Numerous therapeutic approaches for Duchenne and Becker Muscular Dystrophy (DMD and BMD), the most common X-linked muscle degenerative disease, have been proposed. So far, the only one showing a clear beneficial effect is the use of corticosteroids. Recent evidence indicates an improvement of dystrophic cardiac and skeletal muscles in the presence of sustained cGMP levels secondary to a blocking of their degradation by phosphodiesterase five (PDE5). Due to these data, we performed a study to investigate the effect of the specific PDE5 inhibitor, tadalafil, on dystrophic skeletal muscle function. Chronic pharmacological treatment with tadalafil has been carried out in mdx mice. Behavioral and physiological tests, as well as histological and biochemical analyses, confirmed the efficacy of the therapy. We then performed a microarray-based genomic analysis to assess the pattern of gene expression in muscle samples obtained from the different cohorts of animals treated with tadalafil. This scrutiny allowed us to identify several classes of modulated genes. Our results show that PDE5 inhibition can ameliorate dystrophy by acting at different levels. Tadalafil can lead to (1) increased lipid metabolism; (2) a switch towards slow oxidative fibers driven by the up-regulation of PGC-1α; (3) an increased protein synthesis efficiency; (4) a better actin network organization at Z-disk.
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Affiliation(s)
- Valeria De Arcangelis
- Department of Anatomical, Histological, Forensic and Orthopedic Sciences, Sapienza University of Rome, Rome, Italy
| | | | | | - Nicoletta Corbi
- CNR-IBPM, Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | | | - Armando Magrelli
- National Centre for Rare Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Annalisa Onori
- CNR-IBPM, Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Claudio Passananti
- CNR-IBPM, Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Cinzia Pisani
- CNR-IBPM, Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Sophie Rome
- CarMen Laboratory (INSERM 1060, INRA 1362, INSA), University of Lyon, Lyon, France
| | - Cinzia Severini
- CNR-IBCN, Rome, Italy.,European Brain Research Institute, Rome, Italy
| | - Fabio Naro
- Department of Anatomical, Histological, Forensic and Orthopedic Sciences, Sapienza University of Rome, Rome, Italy
| | | | | | - Lucia Monaco
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
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16
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Naproxcinod shows significant advantages over naproxen in the mdx model of Duchenne Muscular Dystrophy. Orphanet J Rare Dis 2015; 10:101. [PMID: 26296873 PMCID: PMC4546261 DOI: 10.1186/s13023-015-0311-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 07/23/2015] [Indexed: 12/18/2022] Open
Abstract
Background In dystrophin-deficient muscles of Duchenne Muscular Dystrophy (DMD) patients and the mdx mouse model, nitric oxide (NO) signalling is impaired. Previous studies have shown that NO-donating drugs are beneficial in dystrophic mouse models. Recently, a long-term treatment (9 months) of mdx mice with naproxcinod, an NO-donating naproxen, has shown a significant improvement of the dystrophic phenotype with beneficial effects present throughout the disease progression. It remains however to be clearly dissected out which specific effects are due to the NO component compared with the anti-inflammatory activity associated with naproxen. Understanding the contribution of NO vs the anti-inflammatory effect is important, in view of the potential therapeutic perspective, and this is the final aim of this study. Methods Five-week-old mdx mice received either naproxcinod (30 mg/kg) or the equimolar dose of naproxen (20 mg/kg) in the diet for 6 months. Control mdx mice were used as reference. Treatments (or vehicle for control groups) were administered daily in the diet. For the first 3 months the study was performed in sedentary animals, then all mice were subjected to exercise until the sixth month. Skeletal muscle force was assessed by measuring whole body tension in sedentary animals as well as in exercised mice and resistance to fatigue was measured after 3 months of running exercise. At the end of 6 months of treatment, animals were sacrificed for histological analysis and measurement of naproxen levels in blood and skeletal muscle. Results Naproxcinod significantly ameliorated skeletal muscle force and resistance to fatigue in sedentary as well as in exercised mice, reduced inflammatory infiltrates and fibrosis deposition in both cardiac and diaphragm muscles. Conversely, the equimolar dose of naproxen showed no effects on fibrosis and improved muscle function only in sedentary mice, while the beneficial effects in exercised mice were lost demonstrating a limited and short-term effect. Conclusion In conclusion, this study shows that NO donation may have an important role, in addition to anti-inflammatory activity, in slowing down the progression of the disease in the mdx mouse model therefore positioning naproxcinod as a promising candidate for treatment of DMD. Electronic supplementary material The online version of this article (doi:10.1186/s13023-015-0311-0) contains supplementary material, which is available to authorized users.
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17
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Ahmad F, Murata T, Shimizu K, Degerman E, Maurice D, Manganiello V. Cyclic nucleotide phosphodiesterases: important signaling modulators and therapeutic targets. Oral Dis 2014; 21:e25-50. [PMID: 25056711 DOI: 10.1111/odi.12275] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 07/09/2014] [Indexed: 02/06/2023]
Abstract
By catalyzing hydrolysis of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), cyclic nucleotide phosphodiesterases are critical regulators of their intracellular concentrations and their biological effects. As these intracellular second messengers control many cellular homeostatic processes, dysregulation of their signals and signaling pathways initiate or modulate pathophysiological pathways related to various disease states, including erectile dysfunction, pulmonary hypertension, acute refractory cardiac failure, intermittent claudication, chronic obstructive pulmonary disease, and psoriasis. Alterations in expression of PDEs and PDE-gene mutations (especially mutations in PDE6, PDE8B, PDE11A, and PDE4) have been implicated in various diseases and cancer pathologies. PDEs also play important role in formation and function of multimolecular signaling/regulatory complexes, called signalosomes. At specific intracellular locations, individual PDEs, together with pathway-specific signaling molecules, regulators, and effectors, are incorporated into specific signalosomes, where they facilitate and regulate compartmentalization of cyclic nucleotide signaling pathways and specific cellular functions. Currently, only a limited number of PDE inhibitors (PDE3, PDE4, PDE5 inhibitors) are used in clinical practice. Future paths to novel drug discovery include the crystal structure-based design approach, which has resulted in generation of more effective family-selective inhibitors, as well as burgeoning development of strategies to alter compartmentalized cyclic nucleotide signaling pathways by selectively targeting individual PDEs and their signalosome partners.
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Affiliation(s)
- F Ahmad
- Cardiovascular and Pulmonary Branch, National Heart, Lung and Blood Institute, Bethesda, MD, USA
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18
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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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19
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Waugh TA, Horstick E, Hur J, Jackson SW, Davidson AE, Li X, Dowling JJ. Fluoxetine prevents dystrophic changes in a zebrafish model of Duchenne muscular dystrophy. Hum Mol Genet 2014; 23:4651-62. [PMID: 24760771 PMCID: PMC4119416 DOI: 10.1093/hmg/ddu185] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a common and relentlessly progressive muscle disease. Some interventions have been identified that modestly slow progression and prolong survival, but more meaningful therapies are lacking. The goal of this study is to identify new therapeutic pathways for DMD using a zebrafish model of the disease. To accomplish this, we performed a non-biased drug screen in sapje, a zebrafish line with a recessive nonsense mutation in dystrophin. We identified 6 positive hits (out of 640 total drugs tested) by their ability to prevent abnormal birefringence in sapje. Follow-up analyses demonstrated that fluoxetine, a selective serotonin reuptake inhibitor (SSRI), provided the most substantial benefit. Morpholino-based experimentation confirmed that modulation of the serotonin pathway alone can prevent the dystrophic phenotype, and transcriptomic analysis revealed changes in calcium homeostasis as a potential mechanism. In all, we demonstrate that monoamine agonists can prevent disease in a vertebrate model of DMD. Given the safe and widespread use of SSRIs in clinical practice, our study identifies an attractive target pathway for therapy development.
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MESH Headings
- Animals
- Base Sequence
- Birefringence
- Calcium/metabolism
- Disease Models, Animal
- Drug Evaluation, Preclinical
- Dystrophin/metabolism
- Embryo, Nonmammalian/drug effects
- Embryo, Nonmammalian/metabolism
- Evans Blue/metabolism
- Fluoxetine/pharmacology
- Fluoxetine/therapeutic use
- Gene Expression Profiling
- Gene Knockdown Techniques
- Homeostasis/drug effects
- Molecular Sequence Data
- Morpholinos/pharmacology
- Muscular Dystrophy, Animal/drug therapy
- Muscular Dystrophy, Animal/genetics
- Muscular Dystrophy, Animal/pathology
- Muscular Dystrophy, Duchenne/drug therapy
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/pathology
- Oligonucleotide Array Sequence Analysis
- Phenotype
- Serotonin Plasma Membrane Transport Proteins/metabolism
- Stress, Mechanical
- Survival Analysis
- Zebrafish/embryology
- Zebrafish/genetics
- Zebrafish/physiology
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Affiliation(s)
| | | | | | | | - Ann E Davidson
- Division of Neurology and Program in Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON, Canada
| | | | - James J Dowling
- Department of Pediatrics, Department of Neurology, and Department of Neuroscience, University of Michigan, Ann Arbor, MI 48109-2200, USA Division of Neurology and Program in Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON, Canada Department of Paediatrics, and Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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20
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Roseguini BT, Hirai DM, Alencar MC, Ramos RP, Silva BM, Wolosker N, Neder JA, Nery LE. Sildenafil improves skeletal muscle oxygenation during exercise in men with intermittent claudication. Am J Physiol Regul Integr Comp Physiol 2014; 307:R396-404. [DOI: 10.1152/ajpregu.00183.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endothelial dysfunction caused by defective nitric oxide (NO) signaling plays a pivotal role in the pathogenesis of intermittent claudication (IC). In the present study, we evaluated the acute effects of sildenafil, a phosphodiesterase type 5 inhibitor that acts by prolonging NO-mediated cGMP signaling in vascular smooth muscle, on blood pressure (BP), skeletal muscle oxygenation, and walking tolerance in patients with IC. A randomized, double-blind, crossover study was conducted in which 12 men with stable IC received two consecutive doses of 50 mg of sildenafil or matching placebo and underwent a symptom-limited exercise test on the treadmill. Changes in gastrocnemius deoxy-hemoglobin by near-infrared spectroscopy estimated peripheral muscle O2delivery-to-utilization matching. Systolic BP was significantly lower during the sildenafil trial relative to placebo during supine rest (∼15 mmHg), submaximal exercise (∼14 mmHg), and throughout recovery (∼18 mmHg) ( P < 0.05). Diastolic BP was also lower after sildenafil during upright rest (∼6 mmHg) and during recovery from exercise (∼7 mmHg) ( P < 0.05). Gastrocnemius deoxygenation was consistently reduced during submaximal exercise (∼41%) and at peak exercise (∼34%) following sildenafil compared with placebo ( P < 0.05). However, pain-free walking time (placebo: 335 ± 42 s vs. sildenafil: 294 ± 35 s) and maximal walking time (placebo: 701 ± 58 s vs. sildenafil: 716 ± 62 s) did not differ between trials. Acute administration of sildenafil lowers BP and improves skeletal muscle oxygenation during exercise but does not enhance walking tolerance in patients with IC. Whether the beneficial effects of sildenafil on muscle oxygenation can be sustained over time and translated into positive clinical outcomes deserve further consideration in this patient population.
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Affiliation(s)
- Bruno T. Roseguini
- Pulmonary Function and Clinical Exercise Physiology Unit, Department of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Daniel M. Hirai
- Pulmonary Function and Clinical Exercise Physiology Unit, Department of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Maria C. Alencar
- Pulmonary Function and Clinical Exercise Physiology Unit, Department of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Roberta P. Ramos
- Pulmonary Function and Clinical Exercise Physiology Unit, Department of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Bruno M. Silva
- Department of Physiology, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Nelson Wolosker
- Department of Surgery, Division of Vascular Surgery, University of Sao Paulo, Sao Paulo, Brazil; and
| | - J. Alberto Neder
- Pulmonary Function and Clinical Exercise Physiology Unit, Department of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil
- Queen's University and Kingston General Hospital, Laboratory of Clinical Exercise Physiology, Department of Medicine, Kingston, Ontario, Canada
| | - Luiz E. Nery
- Pulmonary Function and Clinical Exercise Physiology Unit, Department of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil
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21
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Discovery of 3-(4-hydroxybenzyl)-1-(thiophen-2-yl)chromeno[2,3-c]pyrrol-9(2H)-one as a phosphodiesterase-5 inhibitor and its complex crystal structure. Biochem Pharmacol 2014; 89:86-98. [DOI: 10.1016/j.bcp.2014.02.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 02/12/2014] [Accepted: 02/14/2014] [Indexed: 12/25/2022]
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Zgaljardic DJ, Durham WJ, Mossberg KA, Foreman J, Joshipura K, Masel BE, Urban R, Sheffield-Moore M. Neuropsychological and physiological correlates of fatigue following traumatic brain injury. Brain Inj 2014; 28:389-97. [PMID: 24564698 DOI: 10.3109/02699052.2014.884242] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Fatigue is a common and debilitating phenomenon experienced by individuals with traumatic brain injury (TBI) that can negatively influence rate and extent of functional recovery by reducing participation in brain injury rehabilitation services and increasing maladaptive lifestyle practices. The underlying mechanisms of TBI-related fatigue are not entirely understood and focused research on symptom reduction or prevention is limited. REVIEW The current review of the literature suggests that the aetiology of TBI-related fatigue can be viewed as a multifactorial and complex model impacting physiological systems (i.e. endocrine, skeletal muscle and cardiorespiratory) that can be directly or indirectly influenced by neuropsychological correlates including cognitive and psychological impairment. Distinguishing central from peripheral fatigue is helpful in this regard. Potential therapeutic strategies and pharmacological agents to help alleviate fatigue in this patient population are discussed.
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Percival JM, Siegel MP, Knowels G, Marcinek DJ. Defects in mitochondrial localization and ATP synthesis in the mdx mouse model of Duchenne muscular dystrophy are not alleviated by PDE5 inhibition. Hum Mol Genet 2012; 22:153-67. [PMID: 23049075 DOI: 10.1093/hmg/dds415] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Given the crucial roles for mitochondria in ATP energy supply, Ca(2+) handling and cell death, mitochondrial dysfunction has long been suspected to be an important pathogenic feature in Duchenne muscular dystrophy (DMD). Despite this foresight, mitochondrial function in dystrophin-deficient muscles has remained poorly defined and unknown in vivo. Here, we used the mdx mouse model of DMD and non-invasive spectroscopy to determine the impact of dystrophin-deficiency on skeletal muscle mitochondrial localization and oxidative phosphorylation function in vivo. Mdx mitochondria exhibited significant uncoupling of oxidative phosphorylation (reduced P/O) and a reduction in maximal ATP synthesis capacity that together decreased intramuscular ATP levels. Uncoupling was not driven by increased UCP3 or ANT1 expression. Dystrophin was required to maintain subsarcolemmal mitochondria (SSM) pool density, implicating it in the spatial control of mitochondrial localization. Given that nitric oxide-cGMP pathways regulate mitochondria and that sildenafil-mediated phosphodiesterase 5 inhibition ameliorates dystrophic pathology, we tested whether sildenafil's benefits result from decreased mitochondrial dysfunction in mdx mice. Unexpectedly, sildenafil treatment did not affect mitochondrial content or oxidative phosphorylation defects in mdx mice. Rather, PDE5 inhibition decreased resting levels of ATP, phosphocreatine and myoglobin, suggesting that sildenafil improves dystrophic pathology through other mechanisms. Overall, these data indicate that dystrophin-deficiency disrupts SSM localization, promotes mitochondrial inefficiency and restricts maximal mitochondrial ATP-generating capacity. Together these defects decrease intramuscular ATP and the ability of mdx muscle mitochondria to meet ATP demand. These findings further understanding of how mitochondrial bioenergetic dysfunction contributes to disease pathogenesis in dystrophin-deficient skeletal muscle in vivo.
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Affiliation(s)
- Justin M Percival
- Department of Physiology and Biophysics, University of Washington Medical School, Seattle, WA, USA.
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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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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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