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Naratadam GT, Mecklenburg J, Shein SA, Zou Y, Lai Z, Tumanov AV, Price TJ, Akopian AN. Degenerative and regenerative peripheral processes are associated with persistent painful chemotherapy-induced neuropathies in males and females. Sci Rep 2024; 14:17543. [PMID: 39080341 PMCID: PMC11289433 DOI: 10.1038/s41598-024-68485-6] [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: 12/21/2023] [Accepted: 07/24/2024] [Indexed: 08/02/2024] Open
Abstract
This study investigated the time course of gene expression changes during the progression of persistent painful neuropathy caused by paclitaxel (PTX) in male and female mouse hindpaws and dorsal root ganglia (DRG). Bulk RNA-seq was used to examine these gene expression changes at 1, 16, and 31 days post-last PTX. At these time points, differentially expressed genes (DEGs) were predominantly related to the reduction or increase in epithelial, skin, bone, and muscle development and to angiogenesis, myelination, axonogenesis, and neurogenesis. These processes are accompanied by the regulation of DEGs related to the cytoskeleton, extracellular matrix organization, and cellular energy production. This gene plasticity during the progression of persistent painful neuropathy could be interpreted as a biological process linked to tissue regeneration/degeneration. In contrast, gene plasticity related to immune processes was minimal at 1-31 days after PTX. It was also noted that despite similarities in biological processes and pain chronicity between males and females, specific DEGs differed dramatically according to sex. The main conclusions of this study are that gene expression plasticity in hindpaw and DRG during PTX neuropathy progression similar to tissue regeneration and degeneration, minimally affects immune system processes and is heavily sex-dependent at the individual gene level.
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Affiliation(s)
- George T Naratadam
- South Texas Medical Scientist Training Program (STX-MSTP), Integrated Biomedical Sciences (IBMS) Program, The Long School of Medicine, University of Texas Health Science Center at San Antonio (UTHSCSA), 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA
| | - Jennifer Mecklenburg
- Department of Endodontics, School of Dentistry, University of Texas Health Science Center at San Antonio (UTHSCSA), 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA
| | - Sergey A Shein
- Department of Microbiology, Immunology and Molecular Genetics, The Long School of Medicine, UTHSCSA, San Antonio, TX, 78229, USA
| | - Yi Zou
- Department of Molecular Medicine, The Long School of Medicine, UTHSCSA, San Antonio, TX, 78229, USA
| | - Zhao Lai
- Department of Molecular Medicine, The Long School of Medicine, UTHSCSA, San Antonio, TX, 78229, USA
- Greehey Children's Cancer Research Institute, UTHSCSA, San Antonio, TX, 78229, USA
| | - Alexei V Tumanov
- South Texas Medical Scientist Training Program (STX-MSTP), Integrated Biomedical Sciences (IBMS) Program, The Long School of Medicine, University of Texas Health Science Center at San Antonio (UTHSCSA), 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA.
- Department of Microbiology, Immunology and Molecular Genetics, The Long School of Medicine, UTHSCSA, San Antonio, TX, 78229, USA.
| | - Theodore J Price
- School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX, 75080, USA.
| | - Armen N Akopian
- South Texas Medical Scientist Training Program (STX-MSTP), Integrated Biomedical Sciences (IBMS) Program, The Long School of Medicine, University of Texas Health Science Center at San Antonio (UTHSCSA), 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA.
- Department of Endodontics, School of Dentistry, University of Texas Health Science Center at San Antonio (UTHSCSA), 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA.
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2
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Naratadam GT, Mecklenburg J, Shein SA, Zou Y, Lai Z, Tumanov AV, Price TJ, Akopian AN. Degenerative and regenerative peripheral processes are associated with persistent painful chemotherapy-induced neuropathies in males and females. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.25.577218. [PMID: 38328207 PMCID: PMC10849728 DOI: 10.1101/2024.01.25.577218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
This study aimed to investigate the time course of gene expression changes during the progression of persistent painful neuropathy caused by paclitaxel (PTX) in male and female mouse hind paws and dorsal root ganglia (DRG). Bulk RNA-seq was used to investigate the gene expression changes in the paw and DRG collected at 1, 16, and 31 days post-PTX. At these time points, differentially expressed DEGs were predominantly related to reduction or increase in epithelial, skin, bone, and muscle development and to angiogenesis, myelination, axonogenesis, and neurogenesis. These processes were accompanied by regulation of DEGs related to cytoskeleton, extracellular matrix organization and cellular energy production. This gene plasticity during persistent painful neuropathy progression likely represents biological processes linked to tissue regeneration and degeneration. Unlike regeneration/degeneration, gene plasticity related to immune processes was minimal at 1-31 days post-PTX. It was also noted that despite similarities in biological processes and pain chronicity in males and females, specific DEGs showed dramatic sex-dependency. The main conclusions of this study are that gene expression plasticity in paws and DRG during PTX neuropathy progression relates to tissue regeneration and degeneration, minimally affects the immune system processes, and is heavily sex-dependent at the individual gene level.
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3
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Liao X, Wang Y, Lai X, Wang S. The role of Rapsyn in neuromuscular junction and congenital myasthenic syndrome. BIOMOLECULES & BIOMEDICINE 2023; 23:772-784. [PMID: 36815443 PMCID: PMC10494853 DOI: 10.17305/bb.2022.8641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/02/2023] [Accepted: 02/17/2023] [Indexed: 02/23/2023]
Abstract
Rapsyn, an intracellular scaffolding protein associated with the postsynaptic membranes in the neuromuscular junction (NMJ), is critical for nicotinic acetylcholine receptor clustering and maintenance. Therefore, Rapsyn is essential to the NMJ formation and maintenance, and Rapsyn mutant is one of the reasons causing the pathogenies of congenital myasthenic syndrome (CMS). In addition, there is little research on Rapsyn in the central nervous system (CNS). In this review, the role of Rapsyn in the NMJ formation and the mutation of Rapsyn leading to CMS will be reviewed separately and sequentially. Finally, the potential function of Rapsyn is prospected.
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Affiliation(s)
- Xufeng Liao
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
| | - Yingxing Wang
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
| | - Xinsheng Lai
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
| | - Shunqi Wang
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
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4
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Arnold WD, Clark BC. Neuromuscular junction transmission failure in aging and sarcopenia: The nexus of the neurological and muscular systems. Ageing Res Rev 2023; 89:101966. [PMID: 37270145 PMCID: PMC10847753 DOI: 10.1016/j.arr.2023.101966] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/05/2023] [Accepted: 05/29/2023] [Indexed: 06/05/2023]
Abstract
Sarcopenia, or age-related decline in muscle form and function, exerts high personal, societal, and economic burdens when untreated. Integrity and function of the neuromuscular junction (NMJ), as the nexus between the nervous and muscular systems, is critical for input and dependable neural control of muscle force generation. As such, the NMJ has long been a site of keen interest in the context of skeletal muscle function deficits during aging and in the context of sarcopenia. Historically, changes of NMJ morphology during aging have been investigated extensively but primarily in aged rodent models. Aged rodents have consistently shown features of NMJ endplate fragmentation and denervation. Yet, the presence of NMJ changes in older humans remains controversial, and conflicting findings have been reported. This review article describes the physiological processes involved in NMJ transmission, discusses the evidence that supports NMJ transmission failure as a possible contributor to sarcopenia, and speculates on the potential of targeting these defects for therapeutic development. The technical approaches that are available for assessment of NMJ transmission, whether each approach has been applied in the context of aging and sarcopenia, and the associated findings are summarized. Like morphological studies, age-related NMJ transmission deficits have primarily been studied in rodents. In preclinical studies, isolated synaptic electrophysiology recordings of endplate currents or potentials have been mostly used, and paradoxically, have shown enhancement, rather than failure, with aging. Yet, in vivo assessment of single muscle fiber action potential generation using single fiber electromyography and nerve-stimulated muscle force measurements show evidence of NMJ failure in aged mice and rats. Together these findings suggest that endplate response enhancement may be a compensatory response to post-synaptic mechanisms of NMJ transmission failure in aged rodents. Possible, but underexplored, mechanisms of this failure are discussed including the simplification of post-synaptic folding and altered voltage-gated sodium channel clustering or function. In humans, there is limited clinical data that has selectively investigated single synaptic function in the context of aging. If sarcopenic older adults turn out to exhibit notable impairments in NMJ transmission (this has yet to be examined but based on available evidence appears to be plausible) then these NMJ transmission defects present a well-defined biological mechanism and offer a well-defined pathway for clinical implementation. Investigation of small molecules that are currently available clinically or being testing clinically in other disorders may provide a rapid route for development of interventions for older adults impacted by sarcopenia.
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Affiliation(s)
- W David Arnold
- NextGen Precision Health, University of Missouri System, Columbia, MO, USA; Department of Physical Medicine and Rehabilitation University of Missouri, Columbia, MO, USA.
| | - Brian C Clark
- Ohio Musculoskeletal and Neurological Institute (OMNI) Ohio University, Athens, OH, USA; Department of Biomedical Sciences, Ohio University, Athens, OH, USA.
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5
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DOK7 Promotes NMJ Regeneration After Nerve Injury. Mol Neurobiol 2023; 60:1453-1464. [PMID: 36464749 DOI: 10.1007/s12035-022-03143-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 11/17/2022] [Indexed: 12/11/2022]
Abstract
Motor function recovery from injury requires the regeneration of not only muscle fibers, but also the neuromuscular junction-the synapse between motor nerve terminals and muscle fibers. However, unlike muscle regeneration which has been extensively studied, little is known about the molecular mechanisms of NMJ regeneration. Recognizing the critical role of agrin-LRP4-MuSK signaling in NMJ formation and maintenance, we investigated whether increasing MuSK activity promotes NMJ regeneration. To this end, we evaluated the effect of DOK7, a protein that stimulates MuSK, on NMJ regeneration. Reinnervation, AChR cluster density, and endplate area were improved, and fragmentation was reduced in the AAV9-DOK7-GFP-injected muscles compared with muscles injected with AAV9-GFP. These results demonstrated expedited NMJ regeneration associated with increased DOK7 expression and support the hypothesis that increasing agrin signaling benefits motor function recovery after injury. Our findings propose a potentially new therapeutic strategy for functional recovery after muscle and nerve injury, i.e., promoting NMJ regeneration by increasing agrin signaling.
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6
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Caravia XM, Ramirez-Martinez A, Gan P, Wang F, McAnally JR, Xu L, Bassel-Duby R, Liu N, Olson EN. Loss of function of the nuclear envelope protein LEMD2 causes DNA damage-dependent cardiomyopathy. J Clin Invest 2022; 132:e158897. [PMID: 36377660 PMCID: PMC9663152 DOI: 10.1172/jci158897] [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: 02/03/2022] [Accepted: 09/13/2022] [Indexed: 11/16/2022] Open
Abstract
Mutations in nuclear envelope proteins (NEPs) cause devastating genetic diseases, known as envelopathies, that primarily affect the heart and skeletal muscle. A mutation in the NEP LEM domain-containing protein 2 (LEMD2) causes severe cardiomyopathy in humans. However, the roles of LEMD2 in the heart and the pathological mechanisms responsible for its association with cardiac disease are unknown. We generated knockin (KI) mice carrying the human c.T38>G Lemd2 mutation, which causes a missense amino acid exchange (p.L13>R) in the LEM domain of the protein. These mice represent a preclinical model that phenocopies the human disease, as they developed severe dilated cardiomyopathy and cardiac fibrosis leading to premature death. At the cellular level, KI/KI cardiomyocytes exhibited disorganization of the transcriptionally silent heterochromatin associated with the nuclear envelope. Moreover, mice with cardiac-specific deletion of Lemd2 also died shortly after birth due to heart abnormalities. Cardiomyocytes lacking Lemd2 displayed nuclear envelope deformations and extensive DNA damage and apoptosis linked to p53 activation. Importantly, cardiomyocyte-specific Lemd2 gene therapy via adeno-associated virus rescued cardiac function in KI/KI mice. Together, our results reveal the essentiality of LEMD2 for genome stability and cardiac function and unveil its mechanistic association with human disease.
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Affiliation(s)
- Xurde M. Caravia
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, and
| | - Andres Ramirez-Martinez
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, and
| | - Peiheng Gan
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, and
| | - Feng Wang
- Quantitative Biomedical Research Center, Department of Population and Data Sciences and Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - John R. McAnally
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, and
| | - Lin Xu
- Quantitative Biomedical Research Center, Department of Population and Data Sciences and Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Rhonda Bassel-Duby
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, and
| | - Ning Liu
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, and
| | - Eric N. Olson
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, and
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Iyer SR, Folker ES, Lovering RM. The Nucleoskeleton: Crossroad of Mechanotransduction in Skeletal Muscle. Front Physiol 2021; 12:724010. [PMID: 34721058 PMCID: PMC8554227 DOI: 10.3389/fphys.2021.724010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 09/24/2021] [Indexed: 11/13/2022] Open
Abstract
Intermediate filaments (IFs) are a primary structural component of the cytoskeleton extending throughout the muscle cell (myofiber). Mechanotransduction, the process by which mechanical force is translated into a biochemical signal to activate downstream cellular responses, is crucial to myofiber function. Mechanical forces also act on the nuclear cytoskeleton, which is integrated with the myofiber cytoskeleton by the linker of the nucleoskeleton and cytoskeleton (LINC) complexes. Thus, the nucleus serves as the endpoint for the transmission of force through the cell. The nuclear lamina, a dense meshwork of lamin IFs between the nuclear envelope and underlying chromatin, plays a crucial role in responding to mechanical input; myofibers constantly respond to mechanical perturbation via signaling pathways by activation of specific genes. The nucleus is the largest organelle in cells and a master regulator of cell homeostasis, thus an understanding of how it responds to its mechanical environment is of great interest. The importance of the cell nucleus is magnified in skeletal muscle cells due to their syncytial nature and the extreme mechanical environment that muscle contraction creates. In this review, we summarize the bidirectional link between the organization of the nucleoskeleton and the contractile features of skeletal muscle as they relate to muscle function.
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Affiliation(s)
- Shama R Iyer
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Eric S Folker
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
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8
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The Neuromuscular Junction: Roles in Aging and Neuromuscular Disease. Int J Mol Sci 2021; 22:ijms22158058. [PMID: 34360831 PMCID: PMC8347593 DOI: 10.3390/ijms22158058] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 02/07/2023] Open
Abstract
The neuromuscular junction (NMJ) is a specialized synapse that bridges the motor neuron and the skeletal muscle fiber and is crucial for conversion of electrical impulses originating in the motor neuron to action potentials in the muscle fiber. The consideration of contributing factors to skeletal muscle injury, muscular dystrophy and sarcopenia cannot be restricted only to processes intrinsic to the muscle, as data show that these conditions incur denervation-like findings, such as fragmented NMJ morphology and corresponding functional changes in neuromuscular transmission. Primary defects in the NMJ also influence functional loss in motor neuron disease, congenital myasthenic syndromes and myasthenia gravis, resulting in skeletal muscle weakness and heightened fatigue. Such findings underscore the role that the NMJ plays in neuromuscular performance. Regardless of cause or effect, functional denervation is now an accepted consequence of sarcopenia and muscle disease. In this short review, we provide an overview of the pathologic etiology, symptoms, and therapeutic strategies related to the NMJ. In particular, we examine the role of the NMJ as a disease modifier and a potential therapeutic target in neuromuscular injury and disease.
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9
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Jing H, Chen P, Hui T, Yu Z, Zhou J, Fei E, Wang S, Ren D, Lai X, Li B. Synapse-specific Lrp4 mRNA enrichment requires Lrp4/MuSK signaling, muscle activity and Wnt non-canonical pathway. Cell Biosci 2021; 11:105. [PMID: 34090516 PMCID: PMC8180081 DOI: 10.1186/s13578-021-00619-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 05/25/2021] [Indexed: 11/10/2022] Open
Abstract
Background The neuromuscular junction (NMJ) is a peripheral synapse critical to muscle contraction. Like acetylcholine receptors (AChRs), many essential proteins of NMJ are extremely concentrated at the postjunctional membrane. However, the mechanisms of synapse-specific concentration are not well understood; furthermore, it is unclear whether signaling molecules critical to NMJ formation and maintenance are also locally transcribed. Results We studied the β-gal activity encoded by a lacZ cassette driven by the promoter of the Lrp4 gene. As reported for Lrp4 mRNA, β-gal was in the central region in embryonic muscles and at the NMJ after its formation. However, β-gal was no longer in the central areas of muscle fibers in Lrp4 or MuSK mutant mice, indicating a requirement of Lrp4/MuSK signaling. This phenotype could be rescued by transgenic expression of LRP4 with a transmembrane domain but not soluble ECD in Lrp4 mutant mice. β-gal and AChR clusters were distributed in a broader region in lacZ/ECD than that of heterozygous lacZ/+ mice, indicating an important role of the transmembrane domain in Lrp4 signaling. Synaptic β-gal activity became diffused after denervation or treatment with µ-conotoxin, despite its mRNA was increased, indicating synaptic Lrp4 mRNA enrichment requires muscle activity. β-gal was also diffused in aged mice but became re-concentrated after muscle stimulation. Finally, Lrp4 mRNA was increased in C2C12 myotubes by Wnt ligands in a manner that could be inhibited by RKI-1447, an inhibitor of ROCK in Wnt non-canonical signaling. Injecting RKI-1447 into muscles of adult mice diminished Lrp4 synaptic expression. Conclusions This study demonstrates that synapse-specific enrichment of Lrp4 mRNA requires a coordinated interaction between Lrp4/MuSK signaling, muscle activity, and Wnt non-canonical signaling. Thus, the study provides a new mechanism for Lrp4 mRNA enrichment. It also provides a potential target for the treatment of NMJ aging and other NMJ-related diseases. Supplementary Information The online version contains supplementary material available at 10.1186/s13578-021-00619-z.
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Affiliation(s)
- Hongyang Jing
- School of Life Science, Nanchang University, Nanchang, 330031, China.,Institute of Life Science, Nanchang University, Nanchang, 330031, China
| | - Peng Chen
- School of Life Science, Nanchang University, Nanchang, 330031, China.,Institute of Life Science, Nanchang University, Nanchang, 330031, China
| | - Tiankun Hui
- School of Life Science, Nanchang University, Nanchang, 330031, China.,Institute of Life Science, Nanchang University, Nanchang, 330031, China
| | - Zheng Yu
- School of Life Science, Nanchang University, Nanchang, 330031, China.,Institute of Life Science, Nanchang University, Nanchang, 330031, China
| | - Jin Zhou
- School of Life Science, Nanchang University, Nanchang, 330031, China.,Human Aging Research Institute, Nanchang University, Nanchang, 330031, China
| | - Erkang Fei
- School of Life Science, Nanchang University, Nanchang, 330031, China.,Institute of Life Science, Nanchang University, Nanchang, 330031, China
| | - Shunqi Wang
- School of Life Science, Nanchang University, Nanchang, 330031, China.,Institute of Life Science, Nanchang University, Nanchang, 330031, China
| | - Dongyan Ren
- School of Life Science, Nanchang University, Nanchang, 330031, China.,Institute of Life Science, Nanchang University, Nanchang, 330031, China
| | - Xinsheng Lai
- School of Life Science, Nanchang University, Nanchang, 330031, China. .,Institute of Life Science, Nanchang University, Nanchang, 330031, China.
| | - Baoming Li
- School of Life Science, Nanchang University, Nanchang, 330031, China. .,Institute of Life Science, Nanchang University, Nanchang, 330031, China. .,Department of Psychology and Institute of Brain Science, School of Education, Hangzhou Normal University, Hangzhou, 311121, China.
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Dobrowolny G, Barbiera A, Sica G, Scicchitano BM. Age-Related Alterations at Neuromuscular Junction: Role of Oxidative Stress and Epigenetic Modifications. Cells 2021; 10:1307. [PMID: 34074012 PMCID: PMC8225025 DOI: 10.3390/cells10061307] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/19/2021] [Accepted: 05/22/2021] [Indexed: 12/11/2022] Open
Abstract
With advancing aging, a decline in physical abilities occurs, leading to reduced mobility and loss of independence. Although many factors contribute to the physio-pathological effects of aging, an important event seems to be related to the compromised integrity of the neuromuscular system, which connects the brain and skeletal muscles via motoneurons and the neuromuscular junctions (NMJs). NMJs undergo severe functional, morphological, and molecular alterations during aging and ultimately degenerate. The effect of this decline is an inexorable decrease in skeletal muscle mass and strength, a condition generally known as sarcopenia. Moreover, several studies have highlighted how the age-related alteration of reactive oxygen species (ROS) homeostasis can contribute to changes in the neuromuscular junction morphology and stability, leading to the reduction in fiber number and innervation. Increasing evidence supports the involvement of epigenetic modifications in age-dependent alterations of the NMJ. In particular, DNA methylation, histone modifications, and miRNA-dependent gene expression represent the major epigenetic mechanisms that play a crucial role in NMJ remodeling. It is established that environmental and lifestyle factors, such as physical exercise and nutrition that are susceptible to change during aging, can modulate epigenetic phenomena and attenuate the age-related NMJs changes. This review aims to highlight the recent epigenetic findings related to the NMJ dysregulation during aging and the role of physical activity and nutrition as possible interventions to attenuate or delay the age-related decline in the neuromuscular system.
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Affiliation(s)
- Gabriella Dobrowolny
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics (DAHFMO)-Unit of Histology and Medical Embryology, Sapienza University of Rome, Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, 00161 Rome, Italy;
| | - Alessandra Barbiera
- Department of Life Sciences and Public Health, Histology and Embryology Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (A.B.); (G.S.)
| | - Gigliola Sica
- Department of Life Sciences and Public Health, Histology and Embryology Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (A.B.); (G.S.)
| | - Bianca Maria Scicchitano
- Department of Life Sciences and Public Health, Histology and Embryology Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (A.B.); (G.S.)
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11
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Hui T, Jing H, Zhou T, Chen P, Liu Z, Dong X, Yan M, Ren D, Zou S, Wang S, Fei E, Hong D, Lai X. Increasing LRP4 diminishes neuromuscular deficits in a mouse model of Duchenne muscular dystrophy. Hum Mol Genet 2021; 30:1579-1590. [PMID: 33987657 PMCID: PMC8369839 DOI: 10.1093/hmg/ddab135] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 12/15/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked neuromuscular disease characterized by progressive wasting of skeletal muscles. The neuromuscular junction (NMJ) is a synapse between motor neurons and skeletal muscle fibers, critical for the control of muscle contraction. The NMJ decline is observed in DMD patients, but the mechanism is unclear. LRP4 serves as a receptor for agrin, a proteoglycan secreted by motor neurons to induce NMJ, and plays a critical role in NMJ formation and maintenance. Interestingly, we found that protein levels of LRP4 were reduced both in muscles of the DMD patients and DMD model mdx mice. We explored whether increasing LRP4 is beneficial for DMD and crossed muscle-specific LRP4 transgenic mice with mdx mice (mdx; HSA-LRP4). The LRP4 transgene increased muscle strength, together with improved neuromuscular transmission in mdx mice. Furthermore, we found the LRP4 expression mitigated NMJ fragments and denervation in mdx mice. Mechanically, we showed that overexpression of LRP4 increased the activity of MuSK and expression of dystrophin-associated glycoprotein complex proteins in the mdx mice. Overall, our findings suggest that increasing LRP4 improves both function and structure of NMJ in the mdx mice and Agrin signaling might serve as a new therapeutic strategy in DMD.
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Affiliation(s)
- Tiankun Hui
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Hongyang Jing
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Tian Zhou
- School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Peng Chen
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Ziyang Liu
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Xia Dong
- Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China.,School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Min Yan
- Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China.,School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Dongyan Ren
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Suqi Zou
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Shunqi Wang
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Erkang Fei
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Daojun Hong
- Department of Neurology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Xinsheng Lai
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
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Badawi Y, Nishimune H. Impairment Mechanisms and Intervention Approaches for Aged Human Neuromuscular Junctions. Front Mol Neurosci 2020; 13:568426. [PMID: 33328881 PMCID: PMC7717980 DOI: 10.3389/fnmol.2020.568426] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 10/16/2020] [Indexed: 12/19/2022] Open
Abstract
The neuromuscular junction (NMJ) is a chemical synapse formed between a presynaptic motor neuron and a postsynaptic muscle cell. NMJs in most vertebrate species share many essential features; however, some differences distinguish human NMJs from others. This review will describe the pre- and postsynaptic structures of human NMJs and compare them to NMJs of laboratory animals. We will focus on age-dependent declines in function and changes in the structure of human NMJs. Furthermore, we will describe insights into the aging process revealed from mouse models of accelerated aging. In addition, we will compare aging phenotypes to other human pathologies that cause impairments of pre- and postsynaptic structures at NMJs. Finally, we will discuss potential intervention approaches for attenuating age-related NMJ dysfunction and sarcopenia in humans.
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Affiliation(s)
- Yomna Badawi
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, KS, United States
| | - Hiroshi Nishimune
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, KS, United States.,Neurobiology of Aging, Tokyo Metropolitan Institute of Gerontology, Itabashi, Japan
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