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Juros D, Avila MF, Hastings RL, Pendragon A, Wilson L, Kay J, Valdez G. Cellular and molecular alterations to muscles and neuromuscular synapses in a mouse model of MEGF10-related myopathy. Skelet Muscle 2024; 14:10. [PMID: 38760872 PMCID: PMC11100254 DOI: 10.1186/s13395-024-00342-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 05/04/2024] [Indexed: 05/19/2024] Open
Abstract
Loss-of-function mutations in MEGF10 lead to a rare and understudied neuromuscular disorder known as MEGF10-related myopathy. There are no treatments for the progressive respiratory distress, motor impairment, and structural abnormalities in muscles caused by the loss of MEGF10 function. In this study, we deployed cellular and molecular assays to obtain additional insights about MEGF10-related myopathy in juvenile, young adult, and middle-aged Megf10 knockout (KO) mice. We found fewer muscle fibers in juvenile and adult Megf10 KO mice, supporting published studies that MEGF10 regulates myogenesis by affecting satellite cell differentiation. Interestingly, muscle fibers do not exhibit morphological hallmarks of atrophy in either young adult or middle-aged Megf10 KO mice. We next examined the neuromuscular junction (NMJ), in which MEGF10 has been shown to concentrate postnatally, using light and electron microscopy. We found early and progressive degenerative features at the NMJs of Megf10 KO mice that include increased postsynaptic fragmentation and presynaptic regions not apposed by postsynaptic nicotinic acetylcholine receptors. We also found perisynaptic Schwann cells intruding into the NMJ synaptic cleft. These findings strongly suggest that the NMJ is a site of postnatal pathology in MEGF10-related myopathy. In support of these cellular observations, RNA-seq analysis revealed genes and pathways associated with myogenesis, skeletal muscle health, and NMJ stability dysregulated in Megf10 KO mice compared to wild-type mice. Altogether, these data provide new and valuable cellular and molecular insights into MEGF10-related myopathy.
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Affiliation(s)
- Devin Juros
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA
| | | | - Robert Louis Hastings
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA
| | - Ariane Pendragon
- Department of Neurobiology, Duke University School of Medicine, Durham, NC, USA
| | - Liam Wilson
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA
| | - Jeremy Kay
- Department of Neurobiology, Duke University School of Medicine, Durham, NC, USA
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | - Gregorio Valdez
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA.
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science, Center on the Biology of Aging, Brown University, Providence, RI, USA.
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2
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King PH. Skeletal muscle as a molecular and cellular biomarker of disease progression in amyotrophic lateral sclerosis: a narrative review. Neural Regen Res 2024; 19:747-753. [PMID: 37843208 PMCID: PMC10664124 DOI: 10.4103/1673-5374.382226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 06/27/2023] [Accepted: 07/19/2023] [Indexed: 10/17/2023] Open
Abstract
Amyotrophic lateral sclerosis is a fatal multisystemic neurodegenerative disease with motor neurons being a primary target. Although progressive weakness is a hallmark feature of amyotrophic lateral sclerosis, there is considerable heterogeneity, including clinical presentation, progression, and the underlying triggers for disease initiation. Based on longitudinal studies with families harboring amyotrophic lateral sclerosis-associated gene mutations, it has become apparent that overt disease is preceded by a prodromal phase, possibly in years, where compensatory mechanisms delay symptom onset. Since 85-90% of amyotrophic lateral sclerosis is sporadic, there is a strong need for identifying biomarkers that can detect this prodromal phase as motor neurons have limited capacity for regeneration. Current Food and Drug Administration-approved therapies work by slowing the degenerative process and are most effective early in the disease. Skeletal muscle, including the neuromuscular junction, manifests abnormalities at the earliest stages of the disease, before motor neuron loss, making it a promising source for identifying biomarkers of the prodromal phase. The accessibility of muscle through biopsy provides a lens into the distal motor system at earlier stages and in real time. The advent of "omics" technology has led to the identification of numerous dysregulated molecules in amyotrophic lateral sclerosis muscle, ranging from coding and non-coding RNAs to proteins and metabolites. This technology has opened the door for identifying biomarkers of disease activity and providing insight into disease mechanisms. A major challenge is correlating the myriad of dysregulated molecules with clinical or histological progression and understanding their relevance to presymptomatic phases of disease. There are two major goals of this review. The first is to summarize some of the biomarkers identified in human amyotrophic lateral sclerosis muscle that have a clinicopathological correlation with disease activity, evidence of a similar dysregulation in the SOD1G93A mouse during presymptomatic stages, and evidence of progressive change during disease progression. The second goal is to review the molecular pathways these biomarkers reflect and their potential role in mitigating or promoting disease progression, and as such, their potential as therapeutic targets in amyotrophic lateral sclerosis.
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Affiliation(s)
- Peter H. King
- Department of Neurology and Center for Neurodegeneration and Experimental Therapeutics, The University of Alabama at Birmingham, Birmingham, AL, USA; Birmingham Veterans Affairs Medical Center, Birmingham, AL, USA
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3
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Liu Y, Lin W. Morphological and functional alterations of neuromuscular synapses in a mouse model of ACTA1 congenital myopathy. Hum Mol Genet 2024; 33:233-244. [PMID: 37883471 PMCID: PMC10800017 DOI: 10.1093/hmg/ddad183] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/09/2023] [Accepted: 10/20/2023] [Indexed: 10/28/2023] Open
Abstract
Mutations in skeletal muscle α-actin (Acta1) cause myopathies. In a mouse model of congenital myopathy, heterozygous Acta1 (H40Y) knock-in (Acta1+/Ki) mice exhibit features of human nemaline myopathy, including premature lethality, severe muscle weakness, reduced mobility, and the presence of nemaline rods in muscle fibers. In this study, we investigated the impact of Acta1 (H40Y) mutation on the neuromuscular junction (NMJ). We found that the NMJs were markedly fragmented in Acta1+/Ki mice. Electrophysiological analysis revealed a decrease in amplitude but increase in frequency of miniature end-plate potential (mEPP) at the NMJs in Acta1+/Ki mice, compared with those in wild type (Acta1+/+) mice. Evoked end-plate potential (EPP) remained similar at the NMJs in Acta1+/Ki and Acta1+/+ mice, but quantal content was increased at the NMJs in Acta1+/Ki, compared with Acta1+/+ mice, suggesting a homeostatic compensation at the NMJs in Acta1+/Ki mice to maintain normal levels of neurotransmitter release. Furthermore, short-term synaptic plasticity of the NMJs was compromised in Acta1+/Ki mice. Together, these results demonstrate that skeletal Acta1 H40Y mutation, albeit muscle-origin, leads to both morphological and functional defects at the NMJ.
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Affiliation(s)
- Yun Liu
- Department of Neuroscience, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390-9111, United States
| | - Weichun Lin
- Department of Neuroscience, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390-9111, United States
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4
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Tomé D, Dias MS, Correia J, Almeida RD. Fibroblast growth factor signaling in axons: from development to disease. Cell Commun Signal 2023; 21:290. [PMID: 37845690 PMCID: PMC10577959 DOI: 10.1186/s12964-023-01284-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 08/18/2023] [Indexed: 10/18/2023] Open
Abstract
The fibroblast growth factor (FGF) family regulates various and important aspects of nervous system development, ranging from the well-established roles in neuronal patterning to more recent and exciting functions in axonal growth and synaptogenesis. In addition, FGFs play a critical role in axonal regeneration, particularly after spinal cord injury, confirming their versatile nature in the nervous system. Due to their widespread involvement in neural development, the FGF system also underlies several human neurological disorders. While particular attention has been given to FGFs in a whole-cell context, their effects at the axonal level are in most cases undervalued. Here we discuss the endeavor of the FGF system in axons, we delve into this neuronal subcompartment to provide an original view of this multipurpose family of growth factors in nervous system (dys)function. Video Abstract.
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Affiliation(s)
- Diogo Tomé
- Institute of Biomedicine, Department of Medical Sciences - iBiMED, University of Aveiro, Aveiro, Portugal
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Marta S Dias
- Institute of Biomedicine, Department of Medical Sciences - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Joana Correia
- Institute of Biomedicine, Department of Medical Sciences - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Ramiro D Almeida
- Institute of Biomedicine, Department of Medical Sciences - iBiMED, University of Aveiro, Aveiro, Portugal.
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
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5
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Webb EK, Ng SY, Mikhail AI, Stouth DW, vanLieshout TL, Syroid AL, Ljubicic V. Impact of short-term, pharmacological CARM1 inhibition on skeletal muscle mass, function, and atrophy in mice. Am J Physiol Endocrinol Metab 2023; 325:E252-E266. [PMID: 37493245 PMCID: PMC10625826 DOI: 10.1152/ajpendo.00047.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/20/2023] [Accepted: 07/20/2023] [Indexed: 07/27/2023]
Abstract
Coactivator-associated arginine methyltransferase 1 (CARM1) catalyzes the methylation of arginine residues on target proteins critical for health and disease. The purpose of this study was to characterize the effects of short-term, pharmacological CARM1 inhibition on skeletal muscle size, function, and atrophy. Adult mice (n = 10 or 11/sex) were treated with either a CARM1 inhibitor (150 mg/kg EZM2302; EZM) or vehicle (Veh) via oral gavage for 11-13 days and muscle mass, function, and exercise capacity were assessed. In addition, we investigated the effect of CARM1 suppression on unilateral hindlimb denervation (DEN)-induced muscle atrophy (n = 8/sex). We report that CARM1 inhibition caused significant reductions in the asymmetric dimethylation of known CARM1 substrates but no change in CARM1 protein or mRNA content in skeletal muscle. Reduced CARM1 activity did not affect body or muscle mass, however, we observed a decrease in exercise capacity and muscular endurance in male mice. CARM1 methyltransferase activity increased in the muscle of Veh-treated mice following 7 days of DEN, and this response was blunted in EZM-dosed mice. Skeletal muscle mass and myofiber cross-sectional area were significantly reduced in DEN compared with contralateral, non-DEN limbs to a similar degree in both treatment groups. Furthermore, skeletal muscle atrophy and autophagy gene expression programs were elevated in response to DEN independent of CARM1 suppression. Collectively, these results suggest that short-term, pharmacological CARM1 inhibition in adult animals affects muscle performance in a sex-specific manner but does not impact the maintenance and remodeling of skeletal muscle mass during conditions of neurogenic muscle atrophy.NEW & NOTEWORTHY Short-term pharmacological inhibition of coactivator-associated arginine methyltransferase 1 (CARM1) was effective at significantly reducing CARM1 methyltransferase function in skeletal muscle. CARM1 inhibition did not impact muscle mass, but exercise capacity was impaired, particularly in male mice, whereas morphological and molecular signatures of denervation-induced muscle atrophy were largely maintained in animals administered the inhibitor. Altogether, the role of CARM1 in neuromuscular biology remains complex and requires further investigation of its therapeutic potential in muscle-wasting conditions.
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Affiliation(s)
- Erin K Webb
- Department of Kinesiology, Faculty of Science, McMaster University, Hamilton, Ontario, Canada
| | - Sean Y Ng
- Department of Kinesiology, Faculty of Science, McMaster University, Hamilton, Ontario, Canada
| | - Andrew I Mikhail
- Department of Kinesiology, Faculty of Science, McMaster University, Hamilton, Ontario, Canada
| | - Derek W Stouth
- Department of Kinesiology, Faculty of Science, McMaster University, Hamilton, Ontario, Canada
| | - Tiffany L vanLieshout
- Department of Kinesiology, Faculty of Science, McMaster University, Hamilton, Ontario, Canada
| | - Anika L Syroid
- Department of Kinesiology, Faculty of Science, McMaster University, Hamilton, Ontario, Canada
| | - Vladimir Ljubicic
- Department of Kinesiology, Faculty of Science, McMaster University, Hamilton, Ontario, Canada
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Dasgupta A, Gibbard DF, Schmitt RE, Arneson-Wissink PC, Ducharme AM, Bruinsma ES, Hawse JR, Jatoi A, Doles JD. A TGF-β/KLF10 signaling axis regulates atrophy-associated genes to induce muscle wasting in pancreatic cancer. Proc Natl Acad Sci U S A 2023; 120:e2215095120. [PMID: 37585460 PMCID: PMC10462925 DOI: 10.1073/pnas.2215095120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 06/14/2023] [Indexed: 08/18/2023] Open
Abstract
Cancer cachexia, and its associated complications, represent a large and currently untreatable roadblock to effective cancer management. Many potential therapies have been proposed and tested-including appetite stimulants, targeted cytokine blockers, and nutritional supplementation-yet highly effective therapies are lacking. Innovative approaches to treating cancer cachexia are needed. Members of the Kruppel-like factor (KLF) family play wide-ranging and important roles in the development, maintenance, and metabolism of skeletal muscle. Within the KLF family, we identified KLF10 upregulation in a multitude of wasting contexts-including in pancreatic, lung, and colon cancer mouse models as well as in human patients. We subsequently interrogated loss-of-function of KLF10 as a potential strategy to mitigate cancer associated muscle wasting. In vivo studies leveraging orthotopic implantation of pancreas cancer cells into wild-type and KLF10 KO mice revealed significant preservation of lean mass and robust suppression of pro-atrophy muscle-specific ubiquitin ligases Trim63 and Fbxo32, as well as other factors implicated in atrophy, calcium signaling, and autophagy. Bioinformatics analyses identified Transforming growth factor beta (TGF-β), a known inducer of KLF10 and cachexia promoting factor, as a key upstream regulator of KLF10. We provide direct in vivo evidence that KLF10 KO mice are resistant to the atrophic effects of TGF-β. ChIP-based binding studies demonstrated direct binding to Trim63, a known wasting-associated atrogene. Taken together, we report a critical role for the TGF-β/KLF10 axis in the etiology of pancreatic cancer-associated muscle wasting and highlight the utility of targeting KLF10 as a strategy to prevent muscle wasting and limit cancer-associated cachexia.
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Affiliation(s)
- Aneesha Dasgupta
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN55905
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN46202
- Indiana Center for Musculoskeletal Health, Indianapolis, IN46202
- Tumor Microenvironment & Metastasis Program, Indiana University Simon Comprehensive Cancer Center, Indianapolis, IN46202
| | - Daniel F. Gibbard
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN55905
| | - Rebecca E. Schmitt
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN55905
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN46202
- Indiana Center for Musculoskeletal Health, Indianapolis, IN46202
- Tumor Microenvironment & Metastasis Program, Indiana University Simon Comprehensive Cancer Center, Indianapolis, IN46202
| | - Paige C. Arneson-Wissink
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN55905
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN55905
| | | | | | - John R. Hawse
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN55905
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN55905
| | - Aminah Jatoi
- Department of Oncology, Mayo Clinic, Rochester, MN55905
| | - Jason D. Doles
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN55905
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN46202
- Indiana Center for Musculoskeletal Health, Indianapolis, IN46202
- Tumor Microenvironment & Metastasis Program, Indiana University Simon Comprehensive Cancer Center, Indianapolis, IN46202
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN55905
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7
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Navarro-Martínez A, Vicente-García C, Carvajal JJ. NMJ-related diseases beyond the congenital myasthenic syndromes. Front Cell Dev Biol 2023; 11:1216726. [PMID: 37601107 PMCID: PMC10436495 DOI: 10.3389/fcell.2023.1216726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/21/2023] [Indexed: 08/22/2023] Open
Abstract
Neuromuscular junctions (NMJs) are a special type of chemical synapse that transmits electrical stimuli from motor neurons (MNs) to their innervating skeletal muscle to induce a motor response. They are an ideal model for the study of synapses, given their manageable size and easy accessibility. Alterations in their morphology or function lead to neuromuscular disorders, such as the congenital myasthenic syndromes, which are caused by mutations in proteins located in the NMJ. In this review, we highlight novel potential candidate genes that may cause or modify NMJs-related pathologies in humans by exploring the phenotypes of hundreds of mouse models available in the literature. We also underscore the fact that NMJs may differ between species, muscles or even sexes. Hence the importance of choosing a good model organism for the study of NMJ-related diseases: only taking into account the specific features of the mammalian NMJ, experimental results would be efficiently translated to the clinic.
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Affiliation(s)
| | - Cristina Vicente-García
- Centro Andaluz de Biología del Desarrollo, CSIC-UPO-JA, Universidad Pablo de Olavide, Sevilla, Spain
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8
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Castro RW, Lopes MC, Settlage RE, Valdez G. Aging alters mechanisms underlying voluntary movements in spinal motor neurons of mice, primates, and humans. JCI Insight 2023; 8:e168448. [PMID: 37154159 PMCID: PMC10243831 DOI: 10.1172/jci.insight.168448] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/15/2023] [Indexed: 05/10/2023] Open
Abstract
Spinal motor neurons have been implicated in the loss of motor function that occurs with advancing age. However, the cellular and molecular mechanisms that impair the function of these neurons during aging remain unknown. Here, we show that motor neurons do not die in old female and male mice, rhesus monkeys, and humans. Instead, these neurons selectively and progressively shed excitatory synaptic inputs throughout the soma and dendritic arbor during aging. Thus, aged motor neurons contain a motor circuitry with a reduced ratio of excitatory to inhibitory synapses that may be responsible for the diminished ability to activate motor neurons to commence movements. An examination of the motor neuron translatome (ribosomal transcripts) in male and female mice reveals genes and molecular pathways with roles in glia-mediated synaptic pruning, inflammation, axonal regeneration, and oxidative stress that are upregulated in aged motor neurons. Some of these genes and pathways are also found altered in motor neurons affected with amyotrophic lateral sclerosis (ALS) and responding to axotomy, demonstrating that aged motor neurons are under significant stress. Our findings show mechanisms altered in aged motor neurons that could serve as therapeutic targets to preserve motor function during aging.
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Affiliation(s)
- Ryan W. Castro
- Neuroscience Graduate Program
- Department of Molecular Biology, Cellular Biology, and Biochemistry
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, and
| | - Mikayla C. Lopes
- Department of Molecular Biology, Cellular Biology, and Biochemistry
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, and
- Molecular Biology, Cell Biology, and Biochemistry Graduate Program, Brown University, Providence, Rhode Island, USA
| | - Robert E. Settlage
- Department of Advanced Research Computing, Virginia Tech, Blacksburg, Virginia, USA
| | - Gregorio Valdez
- Department of Molecular Biology, Cellular Biology, and Biochemistry
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, and
- Department of Neurology, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
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9
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Lee YI, Cacciani N, Wen Y, Zhang X, Hedström Y, Thompson W, Larsson L. Direct electrical stimulation impacts on neuromuscular junction morphology on both stimulated and unstimulated contralateral soleus. J Cachexia Sarcopenia Muscle 2023. [PMID: 37060275 DOI: 10.1002/jcsm.13235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 03/06/2023] [Accepted: 03/15/2023] [Indexed: 04/16/2023] Open
Abstract
BACKGROUND There is increasing evidence of crosstalk between organs. The neuromuscular junction (NMJ) is a peripheral chemical synapse whose function and morphology are sensitive to acetylcholine (ACh) release and muscle depolarization. In an attempt to improve our understanding of NMJ plasticity and muscle crosstalk, the effects of unilateral direct electrical stimulation of a hindlimb muscle on the NMJ were investigated in rats exposed long-term post-synaptic neuromuscular blockade. METHODS Sprague Dawley rats were subjected to post-synaptic blockade of neuromuscular transmission by systemic administration of α-cobrotoxin and mechanically ventilated for up to 8 days and compared with untreated sham operated controls and animals exposed to unilateral chronic electrical stimulation 12 h/day for 5 or 8 days. RESULTS NMJs produced axonal and glial sprouts (growth of processes that extend beyond the confines of the synapse defined by high-density aggregates of acetylcholine receptors [AChRs]) in response to post-synaptic neuromuscular blockade, but less than reported after peripheral denervation or pre-synaptic blockade. Direct electrical soleus muscle stimulation reduced the terminal Schwann cell (tSC) and axonal sprouting in both stimulated and non-stimulated contralateral soleus. Eight days chronic stimulation reduced (P < 0.001) the number of tSC sprouts on stimulated and non-stimulated soleus from 6.7 ± 0.5 and 6.9 ± 0.5 sprouts per NMJ, respectively, compared with 10.3 ± 0.9 tSC per NMJ (P < 0.001) in non-stimulated soleus from rats immobilized for 8 days. A similar reduction of axonal sprouts (P < 0.001) was observed in stimulated and non-stimulated contralateral soleus in response to chronic electrical stimulation. RNAseq-based gene expression analyses confirmed a restoring effect on both stimulated and unstimulated contralateral muscle. The cross-over effect was paralleled by increased cytokine/chemokine levels in stimulated and contralateral unstimulated muscle as well as in plasma. CONCLUSIONS Motor axon terminals and terminal Schwann cells at NMJs of rats subjected to post-synaptic neuromuscular blockade exhibited sprouting responses. These axonal and glial responses were likely dampened by a muscle-derived myokines released in an activity-dependent manner with both local and systemic effects.
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Affiliation(s)
- Young Il Lee
- Department of Biology, Texas A&M University, College Station, TX, USA
- Department of Pharmacology & Therapeutics, College of Medicine, University of Florida Myology Institute, University of Florida, Gainesville, FL, USA
| | - Nicola Cacciani
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet, Stockholm, Sweden
| | - Ya Wen
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet, Stockholm, Sweden
| | - Xiang Zhang
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Yvette Hedström
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet, Stockholm, Sweden
| | - Wesley Thompson
- Department of Biology, Texas A&M University, College Station, TX, USA
- Section of Molecular Cell and Developmental Biology, The University of Texas, Austin, TX, USA
| | - Lars Larsson
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Neuroscience, Section of Clinical Neurophysiology, Karolinska Institutet, Stockholm, Sweden
- Viron Molecular Medicine Institute, Boston, MA, USA
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10
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The Cellular and Molecular Signature of ALS in Muscle. J Pers Med 2022; 12:jpm12111868. [PMID: 36579600 PMCID: PMC9692882 DOI: 10.3390/jpm12111868] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 10/29/2022] [Accepted: 11/01/2022] [Indexed: 11/11/2022] Open
Abstract
Amyotrophic lateral sclerosis is a disease affecting upper and lower motor neurons. Although motor neuron death is the core event of ALS pathology, it is increasingly recognized that other tissues and cell types are affected in the disease, making potentially major contributions to the occurrence and progression of pathology. We review here the known cellular and molecular characteristics of muscle tissue affected by ALS. Evidence of toxicity in skeletal muscle tissue is considered, including metabolic dysfunctions, impaired proteostasis, and deficits in muscle regeneration and RNA metabolism. The role of muscle as a secretory organ, and effects on the skeletal muscle secretome are also covered, including the increase in secretion of toxic factors or decrease in essential factors that have consequences for neuronal function and survival.
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11
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Zamboni M, Mazzali G, Brunelli A, Saatchi T, Urbani S, Giani A, Rossi AP, Zoico E, Fantin F. The Role of Crosstalk between Adipose Cells and Myocytes in the Pathogenesis of Sarcopenic Obesity in the Elderly. Cells 2022; 11:3361. [PMID: 36359757 PMCID: PMC9655977 DOI: 10.3390/cells11213361] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/08/2022] [Accepted: 10/14/2022] [Indexed: 11/15/2023] Open
Abstract
As a result of aging, body composition changes, with a decline in muscle mass and an increase in adipose tissue (AT), which reallocates from subcutaneous to visceral depots and stores ectopically in the liver, heart and muscles. Furthermore, with aging, muscle and AT, both of which have recognized endocrine activity, become dysfunctional and contribute, in the case of positive energy balance, to the development of sarcopenic obesity (SO). SO is defined as the co-existence of excess adiposity and low muscle mass and function, and its prevalence increases with age. SO is strongly associated with greater morbidity and mortality. The pathogenesis of SO is complex and multifactorial. This review focuses mainly on the role of crosstalk between age-related dysfunctional adipose and muscle cells as one of the mechanisms leading to SO. A better understanding of this mechanisms may be useful for development of prevention strategies and treatments aimed at reducing the occurrence of SO.
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Affiliation(s)
- Mauro Zamboni
- Geriatrics Division, Department of Surgery, Dentistry, Pediatric and Gynecology, Healthy Aging Center, University of Verona, 37126 Verona, Italy
| | - Gloria Mazzali
- Geriatrics Division, Department of Medicine, University of Verona, 37126 Verona, Italy
| | - Anna Brunelli
- Geriatrics Division, Department of Surgery, Dentistry, Pediatric and Gynecology, Healthy Aging Center, University of Verona, 37126 Verona, Italy
| | - Tanaz Saatchi
- Geriatrics Division, Department of Surgery, Dentistry, Pediatric and Gynecology, Healthy Aging Center, University of Verona, 37126 Verona, Italy
| | - Silvia Urbani
- Geriatrics Division, Department of Surgery, Dentistry, Pediatric and Gynecology, Healthy Aging Center, University of Verona, 37126 Verona, Italy
| | - Anna Giani
- Geriatrics Division, Department of Surgery, Dentistry, Pediatric and Gynecology, Healthy Aging Center, University of Verona, 37126 Verona, Italy
| | - Andrea P. Rossi
- Geriatrics Division, Department of Medicine, AULSS2, Ospedale Ca’Foncello, 31100 Treviso, Italy
| | - Elena Zoico
- Geriatrics Division, Department of Medicine, University of Verona, 37126 Verona, Italy
| | - Francesco Fantin
- Geriatrics Division, Department of Medicine, University of Verona, 37126 Verona, Italy
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12
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Davis LA, Fogarty MJ, Brown A, Sieck GC. Structure and Function of the Mammalian Neuromuscular Junction. Compr Physiol 2022; 12:3731-3766. [PMID: 35950651 PMCID: PMC10461538 DOI: 10.1002/cphy.c210022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The mammalian neuromuscular junction (NMJ) comprises a presynaptic terminal, a postsynaptic receptor region on the muscle fiber (endplate), and the perisynaptic (terminal) Schwann cell. As with any synapse, the purpose of the NMJ is to transmit signals from the nervous system to muscle fibers. This neural control of muscle fibers is organized as motor units, which display distinct structural and functional phenotypes including differences in pre- and postsynaptic elements of NMJs. Motor units vary considerably in the frequency of their activation (both motor neuron discharge rate and duration/duty cycle), force generation, and susceptibility to fatigue. For earlier and more frequently recruited motor units, the structure and function of the activated NMJs must have high fidelity to ensure consistent activation and continued contractile response to sustain vital motor behaviors (e.g., breathing and postural balance). Similarly, for higher force less frequent behaviors (e.g., coughing and jumping), the structure and function of recruited NMJs must ensure short-term reliable activation but not activation sustained for a prolonged period in which fatigue may occur. The NMJ is highly plastic, changing structurally and functionally throughout the life span from embryonic development to old age. The NMJ also changes under pathological conditions including acute and chronic disease. Such neuroplasticity often varies across motor unit types. © 2022 American Physiological Society. Compr Physiol 12:1-36, 2022.
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Affiliation(s)
- Leah A. Davis
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Matthew J. Fogarty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Alyssa Brown
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Gary C. Sieck
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
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13
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Ornitz DM, Itoh N. New developments in the biology of fibroblast growth factors. WIREs Mech Dis 2022; 14:e1549. [PMID: 35142107 PMCID: PMC10115509 DOI: 10.1002/wsbm.1549] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 01/28/2023]
Abstract
The fibroblast growth factor (FGF) family is composed of 18 secreted signaling proteins consisting of canonical FGFs and endocrine FGFs that activate four receptor tyrosine kinases (FGFRs 1-4) and four intracellular proteins (intracellular FGFs or iFGFs) that primarily function to regulate the activity of voltage-gated sodium channels and other molecules. The canonical FGFs, endocrine FGFs, and iFGFs have been reviewed extensively by us and others. In this review, we briefly summarize past reviews and then focus on new developments in the FGF field since our last review in 2015. Some of the highlights in the past 6 years include the use of optogenetic tools, viral vectors, and inducible transgenes to experimentally modulate FGF signaling, the clinical use of small molecule FGFR inhibitors, an expanded understanding of endocrine FGF signaling, functions for FGF signaling in stem cell pluripotency and differentiation, roles for FGF signaling in tissue homeostasis and regeneration, a continuing elaboration of mechanisms of FGF signaling in development, and an expanding appreciation of roles for FGF signaling in neuropsychiatric diseases. This article is categorized under: Cardiovascular Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology Congenital Diseases > Stem Cells and Development Cancer > Stem Cells and Development.
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Affiliation(s)
- David M Ornitz
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nobuyuki Itoh
- Kyoto University Graduate School of Pharmaceutical Sciences, Sakyo, Kyoto, Japan
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14
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Shapiro D, Massopust R, Taetzsch T, Valdez G. Argonaute 2 is lost from neuromuscular junctions affected with amyotrophic lateral sclerosis in SOD1 G93A mice. Sci Rep 2022; 12:4630. [PMID: 35301367 PMCID: PMC8931107 DOI: 10.1038/s41598-022-08455-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 02/24/2022] [Indexed: 01/22/2023] Open
Abstract
miRNAs are necessary for neuromuscular junction (NMJ) health; however, little is known about the proteins required for their activity in this regard. We examined expression of Argonaute 2 (Ago2) and miRNA biogenesis genes in skeletal muscles during development, following nerve injury and in the SOD1G93A ALS mouse model. We found that these genes are enriched in neonate muscles and in adult muscles following nerve injury. Despite widespread NMJ deterioration, these genes were not increased in muscles of SOD1G93A mice. We also found that Ago2 distribution is linked to maturation, innervation, and health of NMJs. Ago2 increasingly concentrates in synaptic regions during NMJ maturation, disperses following experimental denervation and reconcentrates at the NMJ upon reinnervation. Similar to experimentally denervated muscles, a homogenous distribution of Ago2 was observed in SOD1G93A muscle fibers. To determine if Ago2 is necessary for the health of adult muscles, we excised Ago2 from Ago2fl/fl mice using adeno-associated virus mediated Cre recombinase expression. We observed modest changes in muscle histology after 3 months of Ago2 knockdown. Together, these data provide critical insights into the role of Ago2 and miRNA biogenesis genes in healthy and ALS-afflicted skeletal muscles and NMJs.
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Affiliation(s)
- Dillon Shapiro
- Molecular Biology, Cell Biology, & Biochemistry Graduate Program, Brown University, Providence, RI, USA
| | - Ryan Massopust
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA
| | - Thomas Taetzsch
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA
| | - Gregorio Valdez
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA.
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, Brown University, Providence, RI, USA.
- Department of Neurology, Warren Alpert Medical School of Brown University, Providence, USA.
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15
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Doss SV, Barbat-Artigas S, Lopes M, Pradhan BS, Prószyński TJ, Robitaille R, Valdez G. Expression and Roles of Lynx1, a Modulator of Cholinergic Transmission, in Skeletal Muscles and Neuromuscular Junctions in Mice. Front Cell Dev Biol 2022; 10:838612. [PMID: 35372356 PMCID: PMC8967655 DOI: 10.3389/fcell.2022.838612] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 01/31/2022] [Indexed: 11/21/2022] Open
Abstract
Lynx1 is a glycosylphosphatidylinositol (GPI)-linked protein shown to affect synaptic plasticity through modulation of nicotinic acetylcholine receptor (nAChR) subtypes in the brain. Because of this function and structural similarity to α-bungarotoxin, which binds muscle-specific nAChRs with high affinity, Lynx1 is a promising candidate for modulating nAChRs in skeletal muscles. However, little is known about the expression and roles of Lynx1 in skeletal muscles and neuromuscular junctions (NMJs). Here, we show that Lynx1 is expressed in skeletal muscles, increases during development, and concentrates at NMJs. We also demonstrate that Lynx1 interacts with muscle-specific nAChR subunits. Additionally, we present data indicating that Lynx1 deletion alters the response of skeletal muscles to cholinergic transmission and their contractile properties. Based on these findings, we asked if Lynx1 deletion affects developing and adult NMJs. Loss of Lynx1 had no effect on NMJs at postnatal day 9 (P9) and moderately increased their size at P21. Thus, Lynx1 plays a minor role in the structural development of NMJs. In 7- and 12-month-old mice lacking Lynx1, there is a marked increase in the incidence of NMJs with age- and disease-associated morphological alterations. The loss of Lynx1 also reduced the size of adult muscle fibers. Despite these effects, Lynx1 deletion did not alter the rate of NMJ reinnervation and stability following motor axon injury. These findings suggest that Lynx1 is not required during fast remodeling of the NMJ, as is the case during reformation following crushing of motor axons and development. Instead, these data indicate that the primary role of Lynx1 may be to maintain the structure and function of adult and aging NMJs.
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Affiliation(s)
- Sydney V. Doss
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, RI, United States
| | | | - Mikayla Lopes
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, RI, United States
| | - Bhola Shankar Pradhan
- Laboratory of Synaptogenesis, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
- Laboratory of Synaptogenesis, Łukasiewicz Research Network—PORT Polish Center for Technology Development, Wrocław, Poland
| | - Tomasz J. Prószyński
- Laboratory of Synaptogenesis, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
- Laboratory of Synaptogenesis, Łukasiewicz Research Network—PORT Polish Center for Technology Development, Wrocław, Poland
| | - Richard Robitaille
- Département de Neurosciences, Université de Montréal, Montréal, QC, Canada
- Centre de Recherche Interdisciplinaire sur le Cerveau et L’Apprentissage (CIRCA), Montreal, QC, Canada
| | - Gregorio Valdez
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, RI, United States
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, Brown University, Providence, RI, United States
- Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI, United States
- *Correspondence: Gregorio Valdez,
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16
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Verma S, Khurana S, Vats A, Sahu B, Ganguly NK, Chakraborti P, Gourie-Devi M, Taneja V. Neuromuscular Junction Dysfunction in Amyotrophic Lateral Sclerosis. Mol Neurobiol 2022; 59:1502-1527. [PMID: 34997540 DOI: 10.1007/s12035-021-02658-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 11/18/2021] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurological disorder characterized by progressive degeneration of motor neurons leading to skeletal muscle denervation. Earlier studies have shown that motor neuron degeneration begins in motor cortex and descends to the neuromuscular junction (NMJ) in a dying forward fashion. However, accumulating evidences support that ALS is a distal axonopathy where early pathological changes occur at the NMJ, prior to onset of clinical symptoms and propagates towards the motor neuron cell body supporting "dying back" hypothesis. Despite several evidences, series of events triggering NMJ disassembly in ALS are still obscure. Neuromuscular junction is a specialized tripartite chemical synapse which involves a well-coordinated communication among the presynaptic motor neuron, postsynaptic skeletal muscle, and terminal Schwann cells. This review provides comprehensive insight into the role of NMJ in ALS pathogenesis. We have emphasized the molecular alterations in cellular components of NMJ leading to loss of effective neuromuscular transmission in ALS. Further, we provide a preview into research involved in exploring NMJ as potential target for designing effective therapies for ALS.
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Affiliation(s)
- Sagar Verma
- Department of Research, Sir Ganga Ram Hospital, Delhi, India.,Department of Biotechnology, Jamia Hamdard, Delhi, India
| | - Shiffali Khurana
- Department of Research, Sir Ganga Ram Hospital, Delhi, India.,Department of Biomedical Science, Bhaskaracharya College of Applied Sciences, University of Delhi, Delhi, India
| | - Abhishek Vats
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bandana Sahu
- Department of Research, Sir Ganga Ram Hospital, Delhi, India
| | | | | | | | - Vibha Taneja
- Department of Research, Sir Ganga Ram Hospital, Delhi, India.
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17
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Massopust R, Juros D, Shapiro D, Lopes M, Haldar SM, Taetzsch T, Valdez G. KLF15 overexpression in myocytes fails to ameliorate ALS-related pathology or extend the lifespan of SOD1G93A mice. Neurobiol Dis 2022; 162:105583. [PMID: 34902552 PMCID: PMC8750438 DOI: 10.1016/j.nbd.2021.105583] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 11/19/2021] [Accepted: 12/10/2021] [Indexed: 01/22/2023] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a currently incurable disease that causes progressive motor neuron loss, paralysis and death. Skeletal muscle pathology occurs early during the course of ALS. It is characterized by impaired mitochondrial biogenesis, metabolic dysfunction and deterioration of the neuromuscular junction (NMJ), the synapse through which motor neurons communicate with muscles. Therefore, a better understanding of the molecules that underlie this pathology may lead to therapies that slow motor neuron loss and delay ALS progression. Kruppel Like Factor 15 (KLF15) has been identified as a transcription factor that activates alternative metabolic pathways and NMJ maintenance factors, including Fibroblast Growth Factor Binding Protein 1 (FGFBP1), in skeletal myocytes. In this capacity, KLF15 has been shown to play a protective role in Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA), however its role in ALS has not been evaluated. Here, we examined whether muscle-specific KLF15 overexpression promotes the health of skeletal muscles and NMJs in the SOD1G93A ALS mouse model. We show that muscle-specific KLF15 overexpression did not elicit a significant beneficial effect on skeletal muscle atrophy, NMJ health, motor function, or survival in SOD1G93A ALS mice. Our findings suggest that, unlike in mouse models of DMD and SMA, KLF15 overexpression has a minimal impact on ALS disease progression in SOD1G93A mice.
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Affiliation(s)
- Ryan Massopust
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Devin Juros
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Dillon Shapiro
- Molecular Biology, Cell Biology, & Biochemistry Graduate Program, Brown University, Providence, Rhode Island, USA
| | - Mikayla Lopes
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Saptarsi M. Haldar
- Gladstone Institutes, San Francisco, California, USA,Department of Medicine, Cardiology Division, UCSF School of Medicine, San Francisco, California, USA,Current address: Amgen Research, South San Francisco, California, USA
| | - Thomas Taetzsch
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Gregorio Valdez
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA,Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, Brown University, Providence, Rhode Island, USA,Department of Neurology, Warren Alpert Medical School of Brown University, Providence, United States
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18
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Gene Expression Profiling of Skeletal Muscles. Genes (Basel) 2021; 12:genes12111718. [PMID: 34828324 PMCID: PMC8621074 DOI: 10.3390/genes12111718] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/21/2021] [Accepted: 10/27/2021] [Indexed: 12/13/2022] Open
Abstract
Next-generation sequencing provides an opportunity for an in-depth biocomputational analysis to identify gene expression patterns between soleus and tibialis anterior, two well-characterized skeletal muscles, and analyze their gene expression profiling. RNA read counts were analyzed for differential gene expression using the R package edgeR. Differentially expressed genes were filtered using a false discovery rate of less than 0.05 c, a fold-change value of more than twenty, and an association with overrepresented pathways based on the Reactome pathway over-representation analysis tool. Most of the differentially expressed genes associated with soleus are coded for components of lipid metabolism and unique contractile elements. Differentially expressed genes associated with tibialis anterior encoded mostly for glucose and glycogen metabolic pathway regulatory enzymes and calcium-sensitive contractile components. These gene expression distinctions partly explain the genetic basis for skeletal muscle specialization, and they may help to explain skeletal muscle susceptibility to disease and drugs and further refine tissue engineering approaches.
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19
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Moreira-Pais A, Ferreira R, Oliveira PA, Duarte JA. Sarcopenia versus cancer cachexia: the muscle wasting continuum in healthy and diseased aging. Biogerontology 2021; 22:459-477. [PMID: 34324116 DOI: 10.1007/s10522-021-09932-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/21/2021] [Indexed: 12/15/2022]
Abstract
Muscle wasting is one of the major health problems in older adults and is traditionally associated to sarcopenia. Nonetheless, muscle loss may also occur in older adults in the presence of cancer, and in this case, it is associated to cancer cachexia. The clinical management of these conditions is a challenge due to, at least in part, the difficulties in their differential diagnosis. Thus, efforts have been made to better comprehend the pathogenesis of sarcopenia and cancer cachexia, envisioning the improvement of their clinical discrimination and treatment. To add insights on this topic, this review discusses the current knowledge on key molecular players underlying sarcopenia and cancer cachexia in a comparative perspective. Data retrieved from this analysis highlight that while sarcopenia is characterized by the atrophy of fast-twitch muscle fibers, in cancer cachexia an increase in the proportion of fast-twitch fibers appears to happen. The molecular drivers for these specificmuscle remodeling patterns are still unknown; however, among the predominant contributors to sarcopenia is the age-induced neuromuscular denervation, and in cancer cachexia, the muscle disuse experienced by cancer patients seems to play an important role. Moreover, inflammation appears to be more severe in cancer cachexia. Impairment of nutrition-related mediators may also contribute to sarcopenia and cancer cachexia, being distinctly modulated in each condition.
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Affiliation(s)
- Alexandra Moreira-Pais
- CIAFEL, Faculty of Sport, University of Porto, Dr. Plácido da Costa 91, 4200-450, Porto, Portugal. .,LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal. .,Centre for Research and Technology of Agro Environmental and Biological Sciences (CITAB), Inov4Agro, University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801, Vila Real, Portugal. .,Departamento de Química, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
| | - Rita Ferreira
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Paula A Oliveira
- Centre for Research and Technology of Agro Environmental and Biological Sciences (CITAB), Inov4Agro, University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801, Vila Real, Portugal
| | - José A Duarte
- CIAFEL, Faculty of Sport, University of Porto, Dr. Plácido da Costa 91, 4200-450, Porto, Portugal. .,Faculdade de Desporto, Universidade do Porto, Rua Dr. Plácido da Costa 91, 4200-450, Porto, Portugal. .,TOXRUN - Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, Gandra, Portugal.
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20
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Fuertes-Alvarez S, Izeta A. Terminal Schwann Cell Aging: Implications for Age-Associated Neuromuscular Dysfunction. Aging Dis 2021; 12:494-514. [PMID: 33815879 PMCID: PMC7990373 DOI: 10.14336/ad.2020.0708] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/08/2020] [Indexed: 12/11/2022] Open
Abstract
Action potential is transmitted to muscle fibers through specialized synaptic interfaces called neuromuscular junctions (NMJs). These structures are capped by terminal Schwann cells (tSCs), which play essential roles during formation and maintenance of the NMJ. tSCs are implicated in the correct communication between nerves and muscles, and in reinnervation upon injury. During aging, loss of muscle mass and strength (sarcopenia and dynapenia) are due, at least in part, to the progressive loss of contacts between muscle fibers and nerves. Despite the important role of tSCs in NMJ function, very little is known on their implication in the NMJ-aging process and in age-associated denervation. This review summarizes the current knowledge about the implication of tSCs in the age-associated degeneration of NMJs. We also speculate on the possible mechanisms underlying the observed phenotypes.
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Affiliation(s)
- Sandra Fuertes-Alvarez
- 1Biodonostia, Tissue Engineering Group, Paseo Dr. Begiristain, s/n, San Sebastian 20014, Spain
| | - Ander Izeta
- 1Biodonostia, Tissue Engineering Group, Paseo Dr. Begiristain, s/n, San Sebastian 20014, Spain.,2Tecnun-University of Navarra, School of Engineering, Department of Biomedical Engineering and Science, Paseo Mikeletegi, 48, San Sebastian 20009, Spain
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21
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Russo K, Wharton KA. BMP/TGF-β signaling as a modulator of neurodegeneration in ALS. Dev Dyn 2021; 251:10-25. [PMID: 33745185 DOI: 10.1002/dvdy.333] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/12/2021] [Accepted: 03/12/2021] [Indexed: 12/19/2022] Open
Abstract
This commentary focuses on the emerging intersection between BMP/TGF-β signaling roles in nervous system function and the amyotrophic lateral sclerosis (ALS) disease state. Future research is critical to elucidate the molecular underpinnings of this intersection of the cellular processes disrupted in ALS and those influenced by BMP/TGF-β signaling, including synapse structure, neurotransmission, plasticity, and neuroinflammation. Such knowledge promises to inform us of ideal entry points for the targeted modulation of dysfunctional cellular processes in an effort to abrogate ALS pathologies. It is likely that different interventions are required, either at discrete points in disease progression, or across multiple dysfunctional processes which together lead to motor neuron degeneration and death. We discuss the challenging, but intriguing idea that modulation of the pleiotropic nature of BMP/TGF-β signaling could be advantageous, as a way to simultaneously treat defects in more than one cell process across different forms of ALS.
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Affiliation(s)
- Kathryn Russo
- Department of Neuroscience, Brown University, Providence, Rhode Island, USA.,Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, Rhode Island, USA
| | - Kristi A Wharton
- Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, Rhode Island, USA.,Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
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22
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Brayman VL, Taetzsch T, Miko M, Dahal S, Risher WC, Valdez G. Roles of the synaptic molecules Hevin and SPARC in mouse neuromuscular junction development and repair. Neurosci Lett 2021; 746:135663. [PMID: 33493647 DOI: 10.1016/j.neulet.2021.135663] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 01/07/2023]
Abstract
Hevin and secreted protein acidic and rich in cysteine (SPARC) are highly homologous matricellular proteins that function in concert to guide the formation of brain synapses. Here, we investigated the role of these glycoproteins in neuromuscular junction (NMJ) maturation, stability, and repair following injury. Hevin and SPARC mRNA levels in developing (postnatal day 9), adult (postnatal days 90 and 120), and injured (fibular nerve crush) skeletal muscles were assessed with qPCR. Muscle fiber size was analyzed in developing (P9) mice lacking SPARC, Hevin, and both SPARC and Hevin. NMJ morphology was assessed in developing (P9), adult (P90) and injured (fibular nerve crush) mice lacking SPARC, Hevin, and both SPARC and Hevin skeletal muscle. Hevin and SPARC are expressed in skeletal muscles and are upregulated following nerve injury. Hevin-/- mice exhibited delayed NMJ and muscle fiber development but displayed normal NMJ morphology in adulthood and accelerated NMJ reinnervation following nerve injury. Mice lacking SPARC displayed normal NMJ and muscle fiber development but exhibited smaller NMJs with fewer acetylcholine receptor islands in adulthood. Further, SPARC deletion did not result in overt changes in NMJ reformation following nerve injury. The combined deletion of Hevin and SPARC had little effect on NMJ phenotypes observed in single knockouts, however deletion of SPARC in combination with Hevin reversed deficiencies in muscle fiber maturation observed in Hevin-/- muscle. These results identify SPARC and Hevin as extracellular matrix proteins with roles in NMJ development and repair.
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Affiliation(s)
- Vanessa L Brayman
- Fralin Biomedical Research Institute, Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA, 24016, USA; Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, 1 Riverside Circle, Roanoke, VA, 24016, USA
| | - Thomas Taetzsch
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA
| | - MacKenzie Miko
- Fralin Biomedical Research Institute, Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA, 24016, USA
| | - Shreyaska Dahal
- Fralin Biomedical Research Institute, Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA, 24016, USA
| | - W Christopher Risher
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine at Marshall University, 1 John Marshall Drive, Huntington, WV, 25755, USA
| | - Gregorio Valdez
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA; Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, Brown University, Providence, United States; Department of Neurology, Warren Alpert Medical School of Brown University, Providence, United States.
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23
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Rodríguez Cruz PM, Cossins J, Beeson D, Vincent A. The Neuromuscular Junction in Health and Disease: Molecular Mechanisms Governing Synaptic Formation and Homeostasis. Front Mol Neurosci 2020; 13:610964. [PMID: 33343299 PMCID: PMC7744297 DOI: 10.3389/fnmol.2020.610964] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 10/30/2020] [Indexed: 12/28/2022] Open
Abstract
The neuromuscular junction (NMJ) is a highly specialized synapse between a motor neuron nerve terminal and its muscle fiber that are responsible for converting electrical impulses generated by the motor neuron into electrical activity in the muscle fibers. On arrival of the motor nerve action potential, calcium enters the presynaptic terminal, which leads to the release of the neurotransmitter acetylcholine (ACh). ACh crosses the synaptic gap and binds to ACh receptors (AChRs) tightly clustered on the surface of the muscle fiber; this leads to the endplate potential which initiates the muscle action potential that results in muscle contraction. This is a simplified version of the events in neuromuscular transmission that take place within milliseconds, and are dependent on a tiny but highly structured NMJ. Much of this review is devoted to describing in more detail the development, maturation, maintenance and regeneration of the NMJ, but first we describe briefly the most important molecules involved and the conditions that affect their numbers and function. Most important clinically worldwide, are myasthenia gravis (MG), the Lambert-Eaton myasthenic syndrome (LEMS) and congenital myasthenic syndromes (CMS), each of which causes specific molecular defects. In addition, we mention the neurotoxins from bacteria, snakes and many other species that interfere with neuromuscular transmission and cause potentially fatal diseases, but have also provided useful probes for investigating neuromuscular transmission. There are also changes in NMJ structure and function in motor neuron disease, spinal muscle atrophy and sarcopenia that are likely to be secondary but might provide treatment targets. The NMJ is one of the best studied and most disease-prone synapses in the nervous system and it is amenable to in vivo and ex vivo investigation and to systemic therapies that can help restore normal function.
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Affiliation(s)
- Pedro M Rodríguez Cruz
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Judith Cossins
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
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24
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Blasco A, Gras S, Mòdol-Caballero G, Tarabal O, Casanovas A, Piedrafita L, Barranco A, Das T, Pereira SL, Navarro X, Rueda R, Esquerda JE, Calderó J. Motoneuron deafferentation and gliosis occur in association with neuromuscular regressive changes during ageing in mice. J Cachexia Sarcopenia Muscle 2020; 11:1628-1660. [PMID: 32691534 PMCID: PMC7749545 DOI: 10.1002/jcsm.12599] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/05/2020] [Accepted: 06/15/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The cellular mechanisms underlying the age-associated loss of muscle mass and function (sarcopenia) are poorly understood, hampering the development of effective treatment strategies. Here, we performed a detailed characterization of age-related pathophysiological changes in the mouse neuromuscular system. METHODS Young, adult, middle-aged, and old (1, 4, 14, and 24-30 months old, respectively) C57BL/6J mice were used. Motor behavioural and electrophysiological tests and histological and immunocytochemical procedures were carried out to simultaneously analyse structural, molecular, and functional age-related changes in distinct cellular components of the neuromuscular system. RESULTS Ageing was not accompanied by a significant loss of spinal motoneurons (MNs), although a proportion (~15%) of them in old mice exhibited an abnormally dark appearance. Dark MNs were also observed in adult (~9%) and young (~4%) animals, suggesting that during ageing, some MNs undergo early deleterious changes, which may not lead to MN death. Old MNs were depleted of cholinergic and glutamatergic inputs (~40% and ~45%, respectively, P < 0.01), suggestive of age-associated alterations in MN excitability. Prominent microgliosis and astrogliosis [~93% (P < 0.001) and ~100% (P < 0.0001) increase vs. adults, respectively] were found in old spinal cords, with increased density of pro-inflammatory M1 microglia and A1 astroglia (25-fold and 4-fold increase, respectively, P < 0.0001). Ageing resulted in significant reductions in the nerve conduction velocity and the compound muscle action potential amplitude (~30%, P < 0.05, vs. adults) in old distal plantar muscles. Compared with adult muscles, old muscles exhibited significantly higher numbers of both denervated and polyinnervated neuromuscular junctions, changes in fibre type composition, higher proportion of fibres showing central nuclei and lipofuscin aggregates, depletion of satellite cells, and augmented expression of different molecules related to development, plasticity, and maintenance of neuromuscular junctions, including calcitonin gene-related peptide, growth associated protein 43, agrin, fibroblast growth factor binding protein 1, and transforming growth factor-β1. Overall, these alterations occurred at varying degrees in all the muscles analysed, with no correlation between the age-related changes observed and myofiber type composition or muscle topography. CONCLUSIONS Our data provide a global view of age-associated neuromuscular changes in a mouse model of ageing and help to advance understanding of contributing pathways leading to development of sarcopenia.
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Affiliation(s)
- Alba Blasco
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Sílvia Gras
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Guillem Mòdol-Caballero
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, CIBERNED, Bellaterra, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Anna Casanovas
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | | | - Tapas Das
- Abbott Nutrition Research and Development, Columbus, OH, USA
| | | | - Xavier Navarro
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, CIBERNED, Bellaterra, Spain
| | - Ricardo Rueda
- Abbott Nutrition Research and Development, Granada, Spain
| | - Josep E Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
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25
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Galbiati M, Crippa V, Rusmini P, Cristofani R, Messi E, Piccolella M, Tedesco B, Ferrari V, Casarotto E, Chierichetti M, Poletti A. Multiple Roles of Transforming Growth Factor Beta in Amyotrophic Lateral Sclerosis. Int J Mol Sci 2020; 21:ijms21124291. [PMID: 32560258 PMCID: PMC7352289 DOI: 10.3390/ijms21124291] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 12/12/2022] Open
Abstract
Transforming growth factor beta (TGFB) is a pleiotropic cytokine known to be dysregulated in many neurodegenerative disorders and particularly in amyotrophic lateral sclerosis (ALS). This motor neuronal disease is non-cell autonomous, as it affects not only motor neurons but also the surrounding glial cells, and the target skeletal muscle fibers. Here, we analyze the multiple roles of TGFB in these cell types, and how TGFB signaling is altered in ALS tissues. Data reported support a crucial involvement of TGFB in the etiology and progression of ALS, leading us to hypothesize that an imbalance of TGFB signaling, diminished at the pre-symptomatic stage and then increased with time, could be linked to ALS progression. A reduced stimulation of the TGFB pathway at the beginning of disease blocks its neuroprotective effects and promotes glutamate excitotoxicity. At later disease stages, the persistent activation of the TGFB pathway promotes an excessive microglial activation and strengthens muscular dysfunction. The therapeutic potential of TGFB is discussed, in order to foster new approaches to treat ALS.
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26
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Keeler AM, Zieger M, Semple C, Pucci L, Veinbachs A, Brown RH, Mueller C, ElMallah MK. Intralingual and Intrapleural AAV Gene Therapy Prolongs Survival in a SOD1 ALS Mouse Model. Mol Ther Methods Clin Dev 2020; 17:246-257. [PMID: 31970202 PMCID: PMC6962641 DOI: 10.1016/j.omtm.2019.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 12/13/2019] [Indexed: 02/07/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that results in death from respiratory failure. No cure exists for this devastating disease, but therapy that directly targets the respiratory system has the potential to prolong survival and improve quality of life in some cases of ALS. The objective of this study was to enhance breathing and prolong survival by suppressing superoxide dismutase 1 (SOD1) expression in respiratory motor neurons using adeno-associated virus (AAV) expressing an artificial microRNA targeting the SOD1 gene. AAV-miRSOD1 was injected in the tongue and intrapleural space of SOD1G93A mice, and repetitive respiratory and behavioral measurements were performed until the end stage. Robust silencing of SOD1 was observed in the diaphragm and tongue as well as systemically. Silencing of SOD1 prolonged survival by approximately 50 days, and it delayed weight loss and limb weakness in treated animals compared to untreated controls. Histologically, there was preservation of the neuromuscular junctions in the diaphragm as well as the number of axons in the phrenic and hypoglossal nerves. Although SOD1 suppression improved breathing and prolonged survival, it did not ameliorate the restrictive lung phenotype. Suppression of SOD1 expression in motor neurons that underlie respiratory function prolongs survival and enhances breathing until the end stage in SOD1G93A ALS mice.
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Affiliation(s)
- Allison M. Keeler
- Division of Pulmonary Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
- Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA 01655, USA
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Marina Zieger
- Division of Pulmonary Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
- Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA 01655, USA
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Carson Semple
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Logan Pucci
- Department of Pediatrics, Duke University, Durham, NC 27710, USA
| | - Alessandra Veinbachs
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Robert H. Brown
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01655, USA
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Christian Mueller
- Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA 01655, USA
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Mai K. ElMallah
- Division of Pulmonary Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
- Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA 01655, USA
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01655, USA
- Department of Pediatrics, Duke University, Durham, NC 27710, USA
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27
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Pandya VA, Patani R. Decoding the relationship between ageing and amyotrophic lateral sclerosis: a cellular perspective. Brain 2020; 143:1057-1072. [PMID: 31851317 PMCID: PMC7174045 DOI: 10.1093/brain/awz360] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/13/2019] [Accepted: 09/21/2019] [Indexed: 12/13/2022] Open
Abstract
With an ageing population comes an inevitable increase in the prevalence of age-associated neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), a relentlessly progressive and universally fatal disease characterized by the degeneration of upper and lower motor neurons within the brain and spinal cord. Indeed, the physiological process of ageing causes a variety of molecular and cellular phenotypes. With dysfunction at the neuromuscular junction implicated as a key pathological mechanism in ALS, and each lower motor unit cell type vulnerable to its own set of age-related phenotypes, the effects of ageing might in fact prove a prerequisite to ALS, rendering the cells susceptible to disease-specific mechanisms. Moreover, we discuss evidence for overlap between age and ALS-associated hallmarks, potentially implicating cell type-specific ageing as a key contributor to this multifactorial and complex disease. With a dearth of disease-modifying therapy currently available for ALS patients and a substantial failure in bench to bedside translation of other potential therapies, the unification of research in ageing and ALS requires high fidelity models to better recapitulate age-related human disease and will ultimately yield more reliable candidate therapeutics for patients, with the aim of enhancing healthspan and life expectancy.
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Affiliation(s)
- Virenkumar A Pandya
- Department of Neuromuscular Diseases, University College London Queen Square Institute of Neurology, Queen Square, London, UK
- The Francis Crick Institute, London, UK
| | - Rickie Patani
- Department of Neuromuscular Diseases, University College London Queen Square Institute of Neurology, Queen Square, London, UK
- The Francis Crick Institute, London, UK
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28
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Perisynaptic schwann cells - The multitasking cells at the developing neuromuscular junctions. Semin Cell Dev Biol 2020; 104:31-38. [PMID: 32147379 DOI: 10.1016/j.semcdb.2020.02.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 12/27/2022]
Abstract
Neuromuscular junctions (NMJs) are specialized synapses in the peripheral nervous system that allow the transmission of neuronal impulses to skeletal muscles for their contraction. Due to its size and accessibility, the NMJ is a commonly used model for studying basic principles of synapse organization and function. Similar to synapses in the central nervous system, NMJs are composed of presynaptic axonal terminals, the postsynaptic machinery formed at the membrane of the muscle fibers, and the synapse-associated glial cells. The special glial cells at the NMJs are called terminal Schwann cells or perisynaptic Schwann cells (PSCs). Decades of studies on the NMJ, as well as the most recent discoveries, have revealed multiple functions for PSCs at different stages of synaptic formation, maintenance, and disassembly. This review summarizes major observations in the field.
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29
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Baraldo M, Geremia A, Pirazzini M, Nogara L, Solagna F, Türk C, Nolte H, Romanello V, Megighian A, Boncompagni S, Kruger M, Sandri M, Blaauw B. Skeletal muscle mTORC1 regulates neuromuscular junction stability. J Cachexia Sarcopenia Muscle 2020; 11:208-225. [PMID: 31651100 PMCID: PMC7015238 DOI: 10.1002/jcsm.12496] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 08/12/2019] [Accepted: 08/25/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Skeletal muscle is a plastic tissue that can adapt to different stimuli. It is well established that Mammalian Target of Rapamycin Complex 1 (mTORC1) signalling is a key modulator in mediating increases in skeletal muscle mass and function. However, the role of mTORC1 signalling in adult skeletal muscle homeostasis is still not well defined. METHODS Inducible, muscle-specific Raptor and mTOR k.o. mice were generated. Muscles at 1 and 7 months after deletion were analysed to assess muscle histology and muscle force. RESULTS We found no change in muscle size or contractile properties 1 month after deletion. Prolonging deletion of Raptor to 7 months, however, leads to a very marked phenotype characterized by weakness, muscle regeneration, mitochondrial dysfunction, and autophagy impairment. Unexpectedly, reduced mTOR signalling in muscle fibres is accompanied by the appearance of markers of fibre denervation, like the increased expression of the neural cell adhesion molecule (NCAM). Both muscle-specific deletion of mTOR or Raptor, or the use of rapamycin, was sufficient to induce 3-8% of NCAM-positive fibres (P < 0.01), muscle fibrillation, and neuromuscular junction (NMJ) fragmentation in 24% of examined fibres (P < 0.001). Mechanistically, reactivation of autophagy with the small peptide Tat-beclin1 is sufficient to prevent mitochondrial dysfunction and the appearance of NCAM-positive fibres in Raptor k.o. muscles. CONCLUSIONS Our study shows that mTOR signalling in skeletal muscle fibres is critical for maintaining proper fibre innervation, preserving the NMJ structure in both the muscle fibre and the motor neuron. In addition, considering the beneficial effects of exercise in most pathologies affecting the NMJ, our findings suggest that part of these beneficial effects of exercise are through the well-established activation of mTORC1 in skeletal muscle during and after exercise.
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Affiliation(s)
- Martina Baraldo
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Alessia Geremia
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Marco Pirazzini
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Leonardo Nogara
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Francesca Solagna
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Clara Türk
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany
| | - Hendrik Nolte
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany
| | - Vanina Romanello
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Aram Megighian
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Simona Boncompagni
- CeSI-Met-Center for Research on Ageing and Translational Medicine and DNICS, Department of Neuroscience, Imaging and Clinical Sciences, University G. d' Annunzio, Chieti, Italy
| | - Marcus Kruger
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany.,Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Marco Sandri
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Bert Blaauw
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.,Department of Biomedical Sciences, University of Padova, Padova, Italy
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30
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Lacham-Kaplan O, Camera DM, Hawley JA. Divergent Regulation of Myotube Formation and Gene Expression by E2 and EPA during In-Vitro Differentiation of C2C12 Myoblasts. Int J Mol Sci 2020; 21:E745. [PMID: 31979341 PMCID: PMC7037418 DOI: 10.3390/ijms21030745] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 12/21/2022] Open
Abstract
Estrogen (E2) and polyunsaturated fatty acids (n-3PUFA) supplements independently support general wellbeing and enhance muscle regeneration in-vivo and myotube formation in-vitro. However, the combined effect of E2 and n-3PUFA on myoblast differentiation is not known. The purpose of the study was to identify whether E2 and n-3PUFA possess a synergistic effect on in-vitro myogenesis. Mouse C2C12 myoblasts, a reliable model to reiterate myogenic events in-vitro, were treated with 10nM E2 and 50μM eicosapentaenoic acid (EPA) independently or combined, for 0-24 h or 0-120 h during differentiation. Immunofluorescence, targeted qPCR and next generation sequencing (NGS) were used to characterize morphological changes and differential expression of key genes involved in the regulation of myogenesis and muscle function pathways. E2 increased estrogen receptor α (Erα) and the expression of the mitogen-activated protein kinase 11 (Mapk11) within 1 h of treatment and improved myoblast differentiation and myotube formation. A significant reduction (p < 0.001) in myotube formation and in the expression of myogenic regulatory factors Mrfs (MyoD, Myog and Myh1) and the myoblast fusion related gene, Tmem8c, was observed in the presence of EPA and the combined E2/EPA treatment. Additionally, EPA treatment at 48 h of differentiation inhibited the majority of genes associated with the myogenic and striated muscle contraction pathways. In conclusion, EPA and E2 had no synergistic effect on myotube formation in-vitro. Independently, EPA inhibited myoblast differentiation and overrides the stimulatory effect of E2 when used in combination with E2.
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Affiliation(s)
- Orly Lacham-Kaplan
- Exercise and Nutrition Research Program, Mary Mackillop Institute for Health Research, Australian Catholic University, Melbourne 3000, Australia;
| | - Donny M. Camera
- Department of Health and Medical Sciences, Swinburne University of Technology, Melbourne 3122, Australia;
| | - John A. Hawley
- Exercise and Nutrition Research Program, Mary Mackillop Institute for Health Research, Australian Catholic University, Melbourne 3000, Australia;
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31
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Lee YI. Developmental neuromuscular synapse elimination: Activity-dependence and potential downstream effector mechanisms. Neurosci Lett 2019; 718:134724. [PMID: 31877335 DOI: 10.1016/j.neulet.2019.134724] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 12/18/2019] [Accepted: 12/23/2019] [Indexed: 12/12/2022]
Abstract
Synaptic connections initially formed during nervous system development undergo a significant transformation during nervous system maturation. Such maturation is essential for the proper architecture and function of the nervous system. Developmental synaptic transformation includes "synapse elimination," a process in which multiple immature presynaptic inputs converge at and compete for control of a common postsynaptic target. This developmental synaptic remodeling is best understood at mammalian neuromuscular junctions. It is well established that neuromuscular activity provides the impetus for the pruning of redundant motor axon inputs. Despite the dominant influence neuromuscular activity exerts on developmental synapse elimination, however, the downstream mechanisms of neuromuscular activity that affect synapse elimination remain poorly understood. Conversely, although several cellular and molecular effector mechanisms are known to impact synapse elimination, it is unclear whether they are modulated by neuromuscular activity. This review discusses how the motor neurons, synaptic glia and muscle fibers each contributes to the developmental phenomenon, and speculates how neuromuscular activity may modulate these contributions.
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Affiliation(s)
- Young Il Lee
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA.
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32
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Sonjak V, Jacob K, Morais JA, Rivera-Zengotita M, Spendiff S, Spake C, Taivassalo T, Chevalier S, Hepple RT. Fidelity of muscle fibre reinnervation modulates ageing muscle impact in elderly women. J Physiol 2019; 597:5009-5023. [PMID: 31368533 DOI: 10.1113/jp278261] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/30/2019] [Indexed: 12/23/2022] Open
Abstract
KEY POINTS Susceptibility to age-related muscle atrophy relates to the degree of muscle denervation and the capacity of successful reinnervation. However, the specific role of denervation as a determinant of the severity of muscle aging between populations with low versus high physical function has not been addressed. We show that prefrail/frail elderly women exhibited marked features of muscle denervation, whereas world class octogenarian female master athletes showed attenuated indices of denervation and greater reinnervation capacity. These findings suggest that the difference in age-related muscle impact between low- and high-functioning elderly women is the robustness of the response to denervation of myofibers. ABSTRACT Ageing muscle degeneration is a key contributor to physical frailty; however, the factors responsible for exacerbated vs. muted ageing muscle impact are largely unknown. Based upon evidence that susceptibility to neurogenic impact is an important determinant of the severity of ageing muscle degeneration, we aimed to determine the presence and extent of denervation in pre-frail/frail elderly (FE, 77.9 ± 6.2 years) women compared to young physically inactive (YI, 24.0 ± 3.5 years) females, and contrast these findings to high-functioning world class octogenarian female masters athletes (MA, 80.9 ± 6.6 years). Muscle biopsies from vastus lateralis muscle were obtained from all three groups to assess denervation-related morphological and transcriptional markers. The FE group displayed marked grouping of slow fibres, accumulation of very small myofibres, a severe reduction in type IIa/I size ratio, highly variable inter-subject accumulation of neural cell adhesion molecule (NCAM)-positive myofibres, and an accumulation of pyknotic nuclei, indicative of recurring cycles of denervation/reinnervation and persistent denervation. The MA group exhibited a smaller decline in type IIa/I size ratio and fewer pyknotic nuclei, accompanied by a higher degree of type I fibre grouping and larger fibre group size, suggesting a greater reinnervation of denervated fibres. Consistent with this interpretation, MA had higher mRNA levels of the reinnervation-promoting cytokine fibroblast growth factor binding protein 1 (FGFBP1) than FE. Our results indicate that the muscle of FE women has significant neurogenic atrophy, whereas MA muscle exhibit superior reinnervation capacity, suggesting that the difference in age-related muscle impact between low- and high-functioning elderly women is the robustness of the response to denervation of myofibres.
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Affiliation(s)
- Vita Sonjak
- Department of Kinesiology & Physical Education, McGill University, 475 Pine Avenue West, Montreal, Quebec, H2W1S4, Canada.,Research Institute of the McGill University Health Centre, 1001 Decarie Blvd, Montreal, Quebec, H4A3J1, Canada
| | - Kathryn Jacob
- Research Institute of the McGill University Health Centre, 1001 Decarie Blvd, Montreal, Quebec, H4A3J1, Canada
| | - José A Morais
- Research Institute of the McGill University Health Centre, 1001 Decarie Blvd, Montreal, Quebec, H4A3J1, Canada.,Division of Geriatric Medicine, McGill University, 1650 Cedar Avenue, Montreal, Quebec, H3G1A4, Canada.,School of Human Nutrition, McGill University, 21111 Lakeshore Dr, Saint-Anne-de-Bellevue, Quebec, H9X3L9, Canada
| | - Marie Rivera-Zengotita
- Department of Pathology Immunology and Laboratory Medicine, College of Medicine, University of Florida, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
| | - Sally Spendiff
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, 401 Smyth Rd, Ottawa, Canada
| | - Carole Spake
- Medical School, Brown University, 222 Richmond St, Providence, RI, 02903, USA
| | - Tanja Taivassalo
- Department of Physiology and Functional Genomics, University of Florida, 1600 SW Archer Rd, Gainesville, FL, 32603, USA
| | - Stéphanie Chevalier
- Research Institute of the McGill University Health Centre, 1001 Decarie Blvd, Montreal, Quebec, H4A3J1, Canada.,Division of Geriatric Medicine, McGill University, 1650 Cedar Avenue, Montreal, Quebec, H3G1A4, Canada.,School of Human Nutrition, McGill University, 21111 Lakeshore Dr, Saint-Anne-de-Bellevue, Quebec, H9X3L9, Canada
| | - Russell T Hepple
- Department of Physiology and Functional Genomics, University of Florida, 1600 SW Archer Rd, Gainesville, FL, 32603, USA.,Department of Physical Therapy, University of Florida, 1225 Center Drive, Gainesville, FL, 32610, USA
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33
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Lee YI. Differences in the constituent fiber types contribute to the intermuscular variation in the timing of the developmental synapse elimination. Sci Rep 2019; 9:8694. [PMID: 31213646 PMCID: PMC6582271 DOI: 10.1038/s41598-019-45090-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 05/28/2019] [Indexed: 11/09/2022] Open
Abstract
The emergence of a mature nervous system requires a significant refinement of the synaptic connections initially formed during development. Redundant synaptic connections are removed in a process known as synapse elimination. Synapse elimination has been extensively studied at the rodent neuromuscular junction (NMJ). Although several axons initially converge onto each postsynaptic muscle fiber, all redundant inputs are removed during early postnatal development until a single motor neuron innervates each NMJ. Neuronal activity as well as synaptic glia influence the course of synapse elimination. It is, however, unclear whether target muscle fibers are more than naïve substrates in this process. I examined the influence of target myofiber contractile properties on synapse elimination. The timing of redundant input removal in muscles examined correlates strongly with their proportion of slow myofibers: muscles with more slow fibers undergo elimination more slowly. Moreover, this intermuscular difference in the timing of synapse elimination appears to result from local differences in the rate of elimination on fast versus slow myofibers. These results, therefore, imply that differences in the constituent fiber types help account for the variation in the timing of the developmental synapse elimination between muscles and show that the muscle plays a role in the process.
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Affiliation(s)
- Young Il Lee
- Department of Biology, Texas A&M University, College Station, TX, 77843, Texas, USA.
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34
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Abstract
Electrospinning is a versatile and viable technique for generating ultrathin fibers. Remarkable progress has been made with regard to the development of electrospinning methods and engineering of electrospun nanofibers to suit or enable various applications. We aim to provide a comprehensive overview of electrospinning, including the principle, methods, materials, and applications. We begin with a brief introduction to the early history of electrospinning, followed by discussion of its principle and typical apparatus. We then discuss its renaissance over the past two decades as a powerful technology for the production of nanofibers with diversified compositions, structures, and properties. Afterward, we discuss the applications of electrospun nanofibers, including their use as "smart" mats, filtration membranes, catalytic supports, energy harvesting/conversion/storage components, and photonic and electronic devices, as well as biomedical scaffolds. We highlight the most relevant and recent advances related to the applications of electrospun nanofibers by focusing on the most representative examples. We also offer perspectives on the challenges, opportunities, and new directions for future development. At the end, we discuss approaches to the scale-up production of electrospun nanofibers and briefly discuss various types of commercial products based on electrospun nanofibers that have found widespread use in our everyday life.
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Affiliation(s)
- Jiajia Xue
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
| | - Tong Wu
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
| | - Yunqian Dai
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing, Jiangsu 211189, People’s Republic of China
| | - Younan Xia
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
- School of Chemistry and Biochemistry, School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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35
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Abstract
The synapse is an incredibly specialized structure that allows for the coordinated communication of information from one neuron to another. When assembled into circuits, steady streams of excitatory and inhibitory synaptic activity shape neural outputs. At the organismal level, ensembles of neural networks underlie behavior, emotion and memory. Disorder or dysfunctions of synapses, a synaptopathy, may underlie a host of developmental and degenerative neurological conditions. There is a possibility that amyotrophic lateral sclerosis may be a result of a synaptopathy within the neuromotor system. To this end, particular attention has been trained on the excitatory glutamatergic synapses and their morphological proxy, the dendritic spine. The extensive detailing of these dysfunctions in vulnerable neuronal populations, including corticospinal neurons and motor neurons, has recently been the subject of original research in rodents and humans. If amyotrophic lateral sclerosis is indeed a synaptopathy, it is entirely consistent with other proposed pathogenic mechanisms – including glutamate excitotoxicity, accumulation of misfolded proteins and mitochondrial dysfunction at distal axon terminals (cortico-motor neuron and neuromuscular). Further, although the exact mechanism of disease spread from region to region is unknown, the synaptopathy hypothesis is consistent with emerging die-forward evidence and the prion-like propagation of misfolded protein aggregates to distant neuronal populations. Here in this mini-review, we focus on the timeline of synaptic observations in both cortical and spinal neurons from different rodent models, and provide a conceptual framework for assessing the synaptopathy hypothesis in amyotrophic lateral sclerosis.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA; School of Biomedical Sciences, The University of Queensland, St. Lucia, Australia
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36
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Lissouba A, Liao M, Kabashi E, Drapeau P. Transcriptomic Analysis of Zebrafish TDP-43 Transgenic Lines. Front Mol Neurosci 2018; 11:463. [PMID: 30618614 PMCID: PMC6301209 DOI: 10.3389/fnmol.2018.00463] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 11/29/2018] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a late-onset progressive neurodegenerative disorder that affects both upper and lower motor neurons, leading to muscle atrophy with spasticity and eventual death in 3-5 years after the disease onset. More than 50 mutations linked to ALS have been found in the gene TARDBP, encoding the protein TDP-43 that is the predominant component of neuronal inclusions in ALS. TDP-43 is an RNA binding protein with glycine-rich domains that binds to more than 6,000 RNAs in the human brain. However, ALS-related mutations do not appear to affect the function of these genes, indicating that a toxic gain-of-function may occur. We generated transgenic zebrafish lines expressing human TDP-43, either the wild-type form or the ALS-causative G348C mutation identified in a subset of ALS patients, with the transgene expression driven by an inducible heat shock promoter in order to bypass a potential early mortality. The expression of the mutant but not the wild-type human TDP-43 in zebrafish embryos induced a reduction of the locomotor activity in response to touch compared to controls and moderate axonopathy of the motor neurons of the spinal cord, with premature branching of the main axonal branch, recapitulating previous results obtained by mRNA injections. We used these lines to investigate transcriptomic changes due to the presence of mutant TDP-43 using RNA sequencing and have found 159 genes that are differentially expressed compared to control, with 67 genes up-regulated and 92 genes down-regulated. These transcriptomic changes are in line with recent transcriptomic data obtained in mouse models, indicating that these zebrafish transgenic lines are adequate to further study TDP-43-related ALS.
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Affiliation(s)
- Alexandra Lissouba
- Department of Pathology and Cell Biology and Research Center of the University of Montréal Hospital Center, University of Montreal, Montréal, QC, Canada
| | - Meijiang Liao
- Department of Pathology and Cell Biology and Research Center of the University of Montréal Hospital Center, University of Montreal, Montréal, QC, Canada
| | - Edor Kabashi
- UMR CNRS 1127, UPMC INSERM U 1127, CNRS UMR 7225, Institut du Cerveau et de la Moelle épinière, Sorbonne Université Paris VI, Paris, France.,Institut Imagine, UMR INSERM 1163, Hospital Necker-Enfants, Université Paris Descartes, Paris, France
| | - Pierre Drapeau
- Department of Pathology and Cell Biology and Research Center of the University of Montréal Hospital Center, University of Montreal, Montréal, QC, Canada
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Martineau É, Di Polo A, Vande Velde C, Robitaille R. Dynamic neuromuscular remodeling precedes motor-unit loss in a mouse model of ALS. eLife 2018; 7:41973. [PMID: 30320556 PMCID: PMC6234026 DOI: 10.7554/elife.41973] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 10/14/2018] [Indexed: 12/13/2022] Open
Abstract
Despite being an early event in ALS, it remains unclear whether the denervation of neuromuscular junctions (NMJ) is simply the first manifestation of a globally degenerating motor neuron. Using in vivo imaging of single axons and their NMJs over a three-month period, we identify that single motor-units are dismantled asynchronously in SOD1G37R mice. We reveal that weeks prior to complete axonal degeneration, the dismantling of axonal branches is accompanied by contemporaneous new axonal sprouting resulting in synapse formation onto nearby NMJs. Denervation events tend to propagate from the first lost NMJ, consistent with a contribution of neuromuscular factors extrinsic to motor neurons, with distal branches being more susceptible. These results show that NMJ denervation in ALS is a complex and dynamic process of continuous denervation and new innervation rather than a manifestation of sudden global motor neuron degeneration. Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is a fatal neurodegenerative disorder. It occurs when the neurons that control muscles – the motoneurons – disconnect from their target muscles and die. This causes the muscles to weaken and waste away. More and more muscles become affected over time until eventually the muscles that control breathing also become paralyzed. Most patients die within two to five years of diagnosis. Motoneurons consist of a cell body plus a cable-like structure called the axon. The cell body of each motoneuron sits within the spinal cord, and the axon extends out of the spinal cord to the motoneuron’s target muscle. Within the muscle the axon divides into branches, each of which connects with multiple muscle fibers. The breakdown of these connections, known as neuromuscular junctions, is one of the first signs of ALS. Does a motoneuron lose all of its connections with muscle fibers at once, or do the connections break down a few at a time? This distinction is important as it will help to identify the events that lead to muscle paralysis in ALS. To find out, Martineau et al. studied mice that had two genetic mutations: one that causes ALS and another that produces fluorescent molecules in some motoneurons. This allowed the branches of the motoneurons to be tracked over time with a fluorescence microscope. Martineau et al. found that individual neurons lose their connections to muscle fibers gradually. Moreover, motoneurons grow new branches and form new connections even while losing their old ones. This dual process of pruning and budding lasts for several weeks, until eventually the motoneuron dies. Developing drugs to stabilize neuromuscular junctions during the period when motoneurons gradually disconnect from muscles could be a promising avenue to explore to improve the quality of life of ALS patients. One advantage of this treatment strategy is that neuromuscular junctions in muscles are easier to access than motoneurons inside the spinal cord. To identify potential drugs, future studies will need to focus on the proteins and signals that cause the neuromuscular junctions to break down.
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Affiliation(s)
- Éric Martineau
- Département de neurosciences, Université de Montréal, Québec, Canada.,Groupe de recherche sur le système nerveux central, Université de Montréal, Québec, Canada
| | - Adriana Di Polo
- Département de neurosciences, Université de Montréal, Québec, Canada.,Centre de recherche du Centre Hospitalier de l'Université de Montréal, Québec, Canada
| | - Christine Vande Velde
- Département de neurosciences, Université de Montréal, Québec, Canada.,Centre de recherche du Centre Hospitalier de l'Université de Montréal, Québec, Canada
| | - Richard Robitaille
- Département de neurosciences, Université de Montréal, Québec, Canada.,Groupe de recherche sur le système nerveux central, Université de Montréal, Québec, Canada
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38
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Salem M, Al-Tobasei R, Ali A, Lourenco D, Gao G, Palti Y, Kenney B, Leeds TD. Genome-Wide Association Analysis With a 50K Transcribed Gene SNP-Chip Identifies QTL Affecting Muscle Yield in Rainbow Trout. Front Genet 2018; 9:387. [PMID: 30283492 PMCID: PMC6157414 DOI: 10.3389/fgene.2018.00387] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/27/2018] [Indexed: 11/13/2022] Open
Abstract
Detection of coding/functional SNPs that change the biological function of a gene may lead to identification of putative causative alleles within QTL regions and discovery of genetic markers with large effects on phenotypes. This study has two-fold objectives, first to develop, and validate a 50K transcribed gene SNP-chip using RNA-Seq data. To achieve this objective, two bioinformatics pipelines, GATK and SAMtools, were used to identify ~21K transcribed SNPs with allelic imbalances associated with important aquaculture production traits including body weight, muscle yield, muscle fat content, shear force, and whiteness in addition to resistance/susceptibility to bacterial cold-water disease (BCWD). SNPs ere identified from pooled RNA-Seq data collected from ~620 fish, representing 98 families from growth- and 54 families from BCWD-selected lines with divergent phenotypes. In addition, ~29K transcribed SNPs without allelic-imbalances were strategically added to build a 50K Affymetrix SNP-chip. SNPs selected included two SNPs per gene from 14K genes and ~5K non-synonymous SNPs. The SNP-chip was used to genotype 1728 fish. The average SNP calling-rate for samples passing quality control (QC; 1,641 fish) was ≥ 98.5%. The second objective of this study was to test the feasibility of using the new SNP-chip in GWA (Genome-wide association) analysis to identify QTL explaining muscle yield variance. GWA study on 878 fish (representing 197 families from 2 consecutive generations) with muscle yield phenotypes and genotyped for 35K polymorphic markers (passing QC) identified several QTL regions explaining together up to 28.40% of the additive genetic variance for muscle yield in this rainbow trout population. The most significant QTLs were on chromosomes 14 and 16 with 12.71 and 10.49% of the genetic variance, respectively. Many of the annotated genes in the QTL regions were previously reported as important regulators of muscle development and cell signaling. No major QTLs were identified in a previous GWA study using a 57K genomic SNP chip on the same fish population. These results indicate improved detection power of the transcribed gene SNP-chip in the target trait and population, allowing identification of large-effect QTLs for important traits in rainbow trout.
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Affiliation(s)
- Mohamed Salem
- Department of Biology and Molecular Biosciences Program, Middle Tennessee State University, Murfreesboro, TN, United States.,Computational Science Program, Middle Tennessee State University, Murfreesboro, TN, United States
| | - Rafet Al-Tobasei
- Computational Science Program, Middle Tennessee State University, Murfreesboro, TN, United States.,Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ali Ali
- Department of Biology and Molecular Biosciences Program, Middle Tennessee State University, Murfreesboro, TN, United States
| | - Daniela Lourenco
- Department of Animal and Dairy Science, University of Georgia, Athens, GA, United States
| | - Guangtu Gao
- National Center for Cool and Cold Water Aquaculture, USDA Agricultural Research Service, Kearneysville, WV, United States
| | - Yniv Palti
- National Center for Cool and Cold Water Aquaculture, USDA Agricultural Research Service, Kearneysville, WV, United States
| | - Brett Kenney
- Division of Animal and Nutritional Science, West Virginia University, Morgantown, WV, United States
| | - Timothy D Leeds
- National Center for Cool and Cold Water Aquaculture, USDA Agricultural Research Service, Kearneysville, WV, United States
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39
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Causes and consequences of age-related changes at the neuromuscular junction. CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2018.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Taetzsch T, Brayman VL, Valdez G. FGF binding proteins (FGFBPs): Modulators of FGF signaling in the developing, adult, and stressed nervous system. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2983-2991. [PMID: 29902550 DOI: 10.1016/j.bbadis.2018.06.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/17/2018] [Accepted: 06/09/2018] [Indexed: 01/18/2023]
Abstract
Members of the fibroblast growth factor (FGF) family are involved in a variety of cellular processes. In the nervous system, they affect the differentiation and migration of neurons, the formation and maturation of synapses, and the repair of neuronal circuits following insults. Because of the varied yet critical functions of FGF ligands, their availability and activity must be tightly regulated for the nervous system, as well as other tissues, to properly develop and function in adulthood. In this regard, FGF binding proteins (FGFBPs) have emerged as strong candidates for modulating the actions of secreted FGFs in neural and non-neural tissues. Here, we will review the roles of FGFBPs in the peripheral and central nervous systems.
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Affiliation(s)
- Thomas Taetzsch
- Virginia Tech Carilion Research Institute, Roanoke, VA, USA.
| | - Vanessa L Brayman
- Virginia Tech Carilion Research Institute, Roanoke, VA, USA; Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA, USA.
| | - Gregorio Valdez
- Virginia Tech Carilion Research Institute, Roanoke, VA, USA; Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.
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41
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Abstract
As the final output of the somatic nervous system, the neuromuscular junction (NMJ) is essential for all voluntary movements. The NMJ is also necessary for connected cells to function and survive. Because of this central role, much effort has been devoted to understanding the effects of aging, diseases, and injuries on the NMJ. These efforts have revealed a close relationship between aberrant changes at NMJs and its three cellular components - the presynaptic site on motor axons, the postsynaptic region on muscle fibers and perisynaptic Schwann cells. Here, we review the morphological and molecular changes associated with aging NMJs in rodents and humans. We also provide an overview of factors with potential roles in maintaining and repairing adult and aged NMJs.
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Affiliation(s)
- Thomas Taetzsch
- Virginia Tech Carilion Research Institute, Roanoke, Virginia, USA
| | - Gregorio Valdez
- Virginia Tech Carilion Research Institute, Roanoke, Virginia, USA.,Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
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42
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Kapchinsky S, Vuda M, Miguez K, Elkrief D, de Souza AR, Baglole CJ, Aare S, MacMillan NJ, Baril J, Rozakis P, Sonjak V, Pion C, Aubertin-Leheudre M, Morais JA, Jagoe RT, Bourbeau J, Taivassalo T, Hepple RT. Smoke-induced neuromuscular junction degeneration precedes the fibre type shift and atrophy in chronic obstructive pulmonary disease. J Physiol 2018; 596:2865-2881. [PMID: 29663403 DOI: 10.1113/jp275558] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 04/07/2018] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS Chronic obstructive pulmonary disease (COPD) is largely caused by smoking, and patient limb muscle exhibits a fast fibre shift and atrophy. We show that this fast fibre shift is associated with type grouping, suggesting recurring cycles of denervation-reinnervation underlie the type shift. Compared to patients with normal fat-free mass index (FFMI), patients with low FFMI exhibited an exacerbated fibre type shift, marked accumulation of very small persistently denervated muscle fibres, and a blunted denervation-responsive transcript profile, suggesting failed denervation precipitates muscle atrophy in patients with low FFMI. Sixteen weeks of passive tobacco smoke exposure in mice caused neuromuscular junction degeneration, consistent with a key role for smoke exposure in initiating denervation in COPD. ABSTRACT A neurological basis for the fast fibre shift and atrophy seen in limb muscle of patients with chronic obstructive pulmonary disease (COPD) has not been considered previously. The objective of our study was: (1) to determine if denervation contributes to fast fibre shift and muscle atrophy in COPD; and (2) to assess using a preclinical smoking mouse model whether chronic tobacco smoke (TS) exposure could initiate denervation by causing neuromuscular junction (NMJ) degeneration. Vastus lateralis muscle biopsies were obtained from severe COPD patients [n = 10 with low fat-free mass index (FFMI), 65 years; n = 15 normal FFMI, 65 years) and healthy age- and activity-matched non-smoker control subjects (CON; n = 11, 67 years), to evaluate morphological and transcriptional markers of denervation. To evaluate the potential for chronic TS exposure to initiate these changes, we examined NMJ morphology in male adult mice following 16 weeks of passive TS exposure. We observed a high proportion of grouped fast fibres and a denervation transcript profile in COPD patients, suggesting that motor unit remodelling drives the fast fibre type shift in COPD patient limb muscle. A further exacerbation of fast fibre grouping in patients with low FFMI, coupled with blunted reinnervation signals, accumulation of very small non-specific esterase hyperactive fibres and neural cell adhesion molecule-positive type I and type II fibres, suggests denervation-induced exhaustion of reinnervation contributes to muscle atrophy in COPD. Evidence from a smoking mouse model showed significant NMJ degeneration, suggesting that recurring denervation in COPD is probably caused by decades of chronic TS exposure.
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Affiliation(s)
- Sophia Kapchinsky
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
| | - Madhusudanarao Vuda
- Meakins Christie Laboratories and Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Kayla Miguez
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada.,Meakins Christie Laboratories and Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Daren Elkrief
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada.,Meakins Christie Laboratories and Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Angela R de Souza
- Meakins Christie Laboratories and Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Carolyn J Baglole
- Meakins Christie Laboratories and Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Sudhakar Aare
- Meakins Christie Laboratories and Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Norah J MacMillan
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
| | | | - Paul Rozakis
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
| | - Vita Sonjak
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
| | - Charlotte Pion
- Departement des sciences de l'activite physique; GRAPA, Faculte des Sciences, Universite de Quebec a Montreal, Montreal, QC, Canada.,Centre de recherche de l'institut universitaire de geriatrie de Montreal, Montreal, QC, Canada
| | - Mylène Aubertin-Leheudre
- Departement des sciences de l'activite physique; GRAPA, Faculte des Sciences, Universite de Quebec a Montreal, Montreal, QC, Canada.,Centre de recherche de l'institut universitaire de geriatrie de Montreal, Montreal, QC, Canada
| | - Jose A Morais
- Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - R Thomas Jagoe
- McGill Cancer Nutrition Rehabilitation Program and Peter Brojde Lung Cancer Center, Segal Cancer Centre, Jewish General Hospital, Montreal, Canada
| | | | - Tanja Taivassalo
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
| | - Russell T Hepple
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada.,Meakins Christie Laboratories and Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Department of Physical Therapy, University of Florida, USA
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43
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Li Y, Sun S, Ding Z, Yang C, Zhang G, Jiang Q, Zou Y. Temporal and spatial expression of fgfbp genes in zebrafish. Gene 2018; 659:128-136. [PMID: 29551495 DOI: 10.1016/j.gene.2018.03.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 02/22/2018] [Accepted: 03/12/2018] [Indexed: 01/20/2023]
Abstract
Fibroblast growth factor binding proteins (FGFBPs) are a class of secreted proteoglycans that function as an extracellular chaperone for locally stored FGFs and enhance FGF signaling. To date, all three human FGFBP genes have been identified and one orthologue fgfbp1a has been studied in zebrafish embryos. Here, we described the cloning and expression patterns of four novel FGFBP orthologues in zebrafish, fgfbp1b, fgfbp2a, fgfbp2b, and fgfbp3. Quantitative PCR and whole-mount in situ hybridization results showed that all transcripts except fgfbp2a are initially expressed in a maternal manner. fgfbp1b, fgfbp2b and fgfbp2a transcripts are expressed broadly in the head at 24 h post-fertilization (hpf), and then become restricted to the pharyngeal tissue, pectoral fins, and liver, respectively. fgfbp3 is abundantly expressed in the central nervous system (CNS) throughout embryonic and larval development. In adults, fgfbp family manifests the tissue specific patterns of expression with fgfbp3 robustly expressed in muscle and heart. Our work offers a starting point to uncover roles of FGFBP family genes and the possible mechanisms of FGF-dependent and -independent actions of FGFBP in vertebrates.
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Affiliation(s)
- Yana Li
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institute of Biomedical Sciences, Fudan University, Shanghai 200032, PR China
| | - Shuna Sun
- Children's Hospital, Fudan University, Shanghai 200032, PR China
| | - Zhiwen Ding
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institute of Biomedical Sciences, Fudan University, Shanghai 200032, PR China
| | - Chunjie Yang
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institute of Biomedical Sciences, Fudan University, Shanghai 200032, PR China
| | - Guoping Zhang
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institute of Biomedical Sciences, Fudan University, Shanghai 200032, PR China
| | - Qiu Jiang
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institute of Biomedical Sciences, Fudan University, Shanghai 200032, PR China.
| | - Yunzeng Zou
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institute of Biomedical Sciences, Fudan University, Shanghai 200032, PR China.
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44
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Lissouba A, Liao M, Kabashi E, Drapeau P. Transcriptomic Analysis of Zebrafish TDP-43 Transgenic Lines. Front Mol Neurosci 2018. [PMID: 30618614 DOI: 10.3389/fnmol.2018.00463.ecollection2018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a late-onset progressive neurodegenerative disorder that affects both upper and lower motor neurons, leading to muscle atrophy with spasticity and eventual death in 3-5 years after the disease onset. More than 50 mutations linked to ALS have been found in the gene TARDBP, encoding the protein TDP-43 that is the predominant component of neuronal inclusions in ALS. TDP-43 is an RNA binding protein with glycine-rich domains that binds to more than 6,000 RNAs in the human brain. However, ALS-related mutations do not appear to affect the function of these genes, indicating that a toxic gain-of-function may occur. We generated transgenic zebrafish lines expressing human TDP-43, either the wild-type form or the ALS-causative G348C mutation identified in a subset of ALS patients, with the transgene expression driven by an inducible heat shock promoter in order to bypass a potential early mortality. The expression of the mutant but not the wild-type human TDP-43 in zebrafish embryos induced a reduction of the locomotor activity in response to touch compared to controls and moderate axonopathy of the motor neurons of the spinal cord, with premature branching of the main axonal branch, recapitulating previous results obtained by mRNA injections. We used these lines to investigate transcriptomic changes due to the presence of mutant TDP-43 using RNA sequencing and have found 159 genes that are differentially expressed compared to control, with 67 genes up-regulated and 92 genes down-regulated. These transcriptomic changes are in line with recent transcriptomic data obtained in mouse models, indicating that these zebrafish transgenic lines are adequate to further study TDP-43-related ALS.
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Affiliation(s)
- Alexandra Lissouba
- Department of Pathology and Cell Biology and Research Center of the University of Montréal Hospital Center, University of Montreal, Montréal, QC, Canada
| | - Meijiang Liao
- Department of Pathology and Cell Biology and Research Center of the University of Montréal Hospital Center, University of Montreal, Montréal, QC, Canada
| | - Edor Kabashi
- UMR CNRS 1127, UPMC INSERM U 1127, CNRS UMR 7225, Institut du Cerveau et de la Moelle épinière, Sorbonne Université Paris VI, Paris, France
- Institut Imagine, UMR INSERM 1163, Hospital Necker-Enfants, Université Paris Descartes, Paris, France
| | - Pierre Drapeau
- Department of Pathology and Cell Biology and Research Center of the University of Montréal Hospital Center, University of Montreal, Montréal, QC, Canada
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45
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Maguire G. Amyotrophic lateral sclerosis as a protein level, non-genomic disease: Therapy with S2RM exosome released molecules. World J Stem Cells 2017; 9:187-202. [PMID: 29312526 PMCID: PMC5745587 DOI: 10.4252/wjsc.v9.i11.187] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/10/2017] [Accepted: 09/04/2017] [Indexed: 02/06/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a rapidly progressing neurodegenerative disease that leads to death. No effective treatments are currently available. Based on data from epidemiological, etiological, laboratory, and clinical studies, I offer a new way of thinking about ALS and its treatment. This paper describes a host of extrinsic factors, including the exposome, that disrupt the extracellular matrix and protein function such that a spreading, prion-like disease leads to neurodegeneration in the motor tracts. A treatment regimen is described using the stem cell released molecules from a number of types of adult stem cells to provide tissue dependent molecules that restore homeostasis, including proteostasis, in the ALS patient. Because stem cells themselves as a therapeutic are cumbersome and expensive, and when implanted in a host cause aging of the host tissue and often fail to engraft or remain viable, only the S2RM molecules are used. Rebuilding of the extracellular matrix and repair of the dysfunctional proteins in the ALS patient ensues.
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Affiliation(s)
- Greg Maguire
- BioRegenerative Sciences, Inc., La Jolla, CA 92037, United States
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46
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Mills R, Taylor-Weiner H, Correia JC, Agudelo LZ, Allodi I, Kolonelou C, Martinez-Redondo V, Ferreira DMS, Nichterwitz S, Comley LH, Lundin V, Hedlund E, Ruas JL, Teixeira AI. Neurturin is a PGC-1α1-controlled myokine that promotes motor neuron recruitment and neuromuscular junction formation. Mol Metab 2017; 7:12-22. [PMID: 29157948 PMCID: PMC5784328 DOI: 10.1016/j.molmet.2017.11.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 10/31/2017] [Accepted: 11/01/2017] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE We examined whether skeletal muscle overexpression of PGC-1α1 or PGC-1α4 affected myokine secretion and neuromuscular junction (NMJ) formation. METHODS A microfluidic device was used to model endocrine signaling and NMJ formation between primary mouse myoblast-derived myotubes and embryonic stem cell-derived motor neurons. Differences in hydrostatic pressure allowed for fluidic isolation of either cell type or unidirectional signaling in the fluid phase. Myotubes were transduced to overexpress PGC-1α1 or PGC-1α4, and myokine secretion was quantified using a proximity extension assay. Morphological and functional changes in NMJs were measured by fluorescent microscopy and by monitoring muscle contraction upon motor neuron stimulation. RESULTS Skeletal muscle transduction with PGC-1α1, but not PGC-1α4, increased NMJ formation and size. PGC-1α1 increased muscle secretion of neurturin, which was sufficient and necessary for the effects of muscle PGC-1α1 on NMJ formation. CONCLUSIONS Our findings indicate that neurturin is a mediator of PGC-1α1-dependent retrograde signaling from muscle to motor neurons.
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Affiliation(s)
- Richard Mills
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles väg 2, 171 77, Stockholm, Sweden
| | - Hermes Taylor-Weiner
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles väg 2, 171 77, Stockholm, Sweden
| | - Jorge C Correia
- Molecular and Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, von Eulers väg 8, 171 77, Stockholm, Sweden
| | - Leandro Z Agudelo
- Molecular and Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, von Eulers väg 8, 171 77, Stockholm, Sweden
| | - Ilary Allodi
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177, Stockholm, Sweden
| | - Christina Kolonelou
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles väg 2, 171 77, Stockholm, Sweden
| | - Vicente Martinez-Redondo
- Molecular and Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, von Eulers väg 8, 171 77, Stockholm, Sweden
| | - Duarte M S Ferreira
- Molecular and Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, von Eulers väg 8, 171 77, Stockholm, Sweden
| | - Susanne Nichterwitz
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177, Stockholm, Sweden
| | - Laura H Comley
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177, Stockholm, Sweden
| | - Vanessa Lundin
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles väg 2, 171 77, Stockholm, Sweden
| | - Eva Hedlund
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177, Stockholm, Sweden
| | - Jorge L Ruas
- Molecular and Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, von Eulers väg 8, 171 77, Stockholm, Sweden.
| | - Ana I Teixeira
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles väg 2, 171 77, Stockholm, Sweden.
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47
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Cappello V, Francolini M. Neuromuscular Junction Dismantling in Amyotrophic Lateral Sclerosis. Int J Mol Sci 2017; 18:ijms18102092. [PMID: 28972545 PMCID: PMC5666774 DOI: 10.3390/ijms18102092] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/25/2017] [Accepted: 09/28/2017] [Indexed: 12/13/2022] Open
Abstract
Neuromuscular junction assembly and plasticity during embryonic, postnatal, and adult life are tightly regulated by the continuous cross-talk among motor nerve endings, muscle fibers, and glial cells. Altered communications among these components is thought to be responsible for the physiological age-related changes at this synapse and possibly for its destruction in pathological states. Neuromuscular junction dismantling plays a crucial role in the onset of Amyotrophic Lateral Sclerosis (ALS). ALS is characterized by the degeneration and death of motor neurons leading to skeletal muscle denervation, atrophy and, most often, death of the patient within five years from diagnosis. ALS is a non-cell autonomous disease as, besides motor neuron degeneration, glial cells, and possibly muscle fibers, play a role in its onset and progression. Here, we will review the recent literature regarding the mechanisms leading to neuromuscular junction disassembly and muscle denervation focusing on the role of the three players of this peripheral tripartite synapse.
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Affiliation(s)
- Valentina Cappello
- Center for Nanotechnology Innovation@NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12, 56127 Pisa, Italy.
| | - Maura Francolini
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano-Via Vanvitelli 32, 20129 Milano, Italy.
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Rogers RS, Tungtur S, Tanaka T, Nadeau LL, Badawi Y, Wang H, Ni HM, Ding WX, Nishimune H. Impaired Mitophagy Plays a Role in Denervation of Neuromuscular Junctions in ALS Mice. Front Neurosci 2017; 11:473. [PMID: 28890682 PMCID: PMC5575151 DOI: 10.3389/fnins.2017.00473] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 08/10/2017] [Indexed: 12/11/2022] Open
Abstract
Motor neurons in amyotrophic lateral sclerosis (ALS) patients and animal models show degeneration from the nerve terminal, known as dying-back neuropathy. To investigate the mechanism underlying this neuropathy, we analyzed the neuromuscular junctions (NMJs) and motor neuron cell bodies in SOD1G93A mice using electron microscopy. NMJs of SOD1G93A mice exhibited significantly higher numbers of autophagosomes and degenerated mitochondria compared to wild-type controls. Mitophagosomes were identified in the NMJ presynaptic terminals of wild-type mice and SOD1G93A mice. However, the number of mitophagosomes did not increase significantly in SOD1G93A NMJs indicating a defect in mitophagy, the autophagic process to degrade mitochondria. Consistent with this, proteins essential for mitophagy, p62/SQSTM1, Bnip3, Pink1, and Parkin were down-regulated in motor neurons in SOD1G93A mice. Importantly, SQSTM1 is one of the genes mutated in familial ALS patients. We evaluated the effect of impaired mitophagy on motor neurons by analyzing the double knockout mice of Pink1 and Parkin, two genes responsible for sensing depolarized mitochondria and delivering degenerated mitochondria to mitophagosomes. The double knockout mice exhibited NMJ degeneration, including axon swelling and NMJ fragmentation at 4 months of age. These phenotypes were rarely observed in wild-type control mice of the same age. The protein level of ATP synthase β subunit increased in the NMJ presynaptic terminals, suggesting the accumulation of mitochondria at NMJs of the double knockout mice. Importantly, NMJ denervation was observed in the double knockout mice. These data suggest that the reduced mitophagy function in motor neurons of SOD1G93A mice is one of the mechanisms causing degeneration of ALS NMJs.
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Affiliation(s)
- Robert S Rogers
- Department of Anatomy and Cell Biology, University of Kansas School of MedicineKansas City, KS, United States
| | - Sudheer Tungtur
- Department of Anatomy and Cell Biology, University of Kansas School of MedicineKansas City, KS, United States
| | - Tomohiro Tanaka
- Department of Anatomy and Cell Biology, University of Kansas School of MedicineKansas City, KS, United States
| | - Lisa L Nadeau
- Department of Anatomy and Cell Biology, University of Kansas School of MedicineKansas City, KS, United States
| | - Yomna Badawi
- Department of Anatomy and Cell Biology, University of Kansas School of MedicineKansas City, KS, United States
| | - Hua Wang
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas School of MedicineKansas City, KS, United States
| | - Hong-Min Ni
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas School of MedicineKansas City, KS, United States
| | - Wen-Xing Ding
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas School of MedicineKansas City, KS, United States
| | - Hiroshi Nishimune
- Department of Anatomy and Cell Biology, University of Kansas School of MedicineKansas City, KS, United States
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49
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Giudice J, Taylor JM. Muscle as a paracrine and endocrine organ. Curr Opin Pharmacol 2017; 34:49-55. [PMID: 28605657 PMCID: PMC5808999 DOI: 10.1016/j.coph.2017.05.005] [Citation(s) in RCA: 190] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 05/22/2017] [Accepted: 05/25/2017] [Indexed: 01/05/2023]
Abstract
Skeletal muscle cells are highly abundant and metabolically active and are known to 'communicate' their energy demands to other organs through active secretion. Muscle-derived secretory proteins include a variety of cytokines and peptides collectively referred to as 'myokines' that exert autocrine, paracrine or endocrine effects. Analyses of the skeletal muscle secretome revealed that numerous myokines are secreted in response to contraction or strength training, and that these factors not only regulate energy demand but also contribute to the broad beneficial effects of exercise on cardiovascular, metabolic, and mental health. Herein we review recent studies on the myokines that regulate muscle function and those that mediate cross talk between skeletal muscle and other organs including adipose tissue, liver, pancreas, the cardiovascular system, brain, bones, and skin.
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Affiliation(s)
- Jimena Giudice
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA; McAllister Heart Institute, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Joan M Taylor
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Pathology, University of North Carolina, Chapel Hill, NC 27599, USA.
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