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Li A, Yi J, Li X, Dong L, Ostrow LW, Ma J, Zhou J. Distinct transcriptomic profile of satellite cells contributes to preservation of neuromuscular junctions in extraocular muscles of ALS mice. eLife 2024; 12:RP92644. [PMID: 38661532 PMCID: PMC11045223 DOI: 10.7554/elife.92644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neuromuscular disorder characterized by progressive weakness of almost all skeletal muscles, whereas extraocular muscles (EOMs) are comparatively spared. While hindlimb and diaphragm muscles of end-stage SOD1G93A (G93A) mice (a familial ALS mouse model) exhibit severe denervation and depletion of Pax7+satellite cells (SCs), we found that the pool of SCs and the integrity of neuromuscular junctions (NMJs) are maintained in EOMs. In cell sorting profiles, SCs derived from hindlimb and diaphragm muscles of G93A mice exhibit denervation-related activation, whereas SCs from EOMs of G93A mice display spontaneous (non-denervation-related) activation, similar to SCs from wild-type mice. Specifically, cultured EOM SCs contain more abundant transcripts of axon guidance molecules, including Cxcl12, along with more sustainable renewability than the diaphragm and hindlimb counterparts under differentiation pressure. In neuromuscular co-culture assays, AAV-delivery of Cxcl12 to G93A-hindlimb SC-derived myotubes enhances motor neuron axon extension and innervation, recapitulating the innervation capacity of EOM SC-derived myotubes. G93A mice fed with sodium butyrate (NaBu) supplementation exhibited less NMJ loss in hindlimb and diaphragm muscles. Additionally, SCs derived from G93A hindlimb and diaphragm muscles displayed elevated expression of Cxcl12 and improved renewability following NaBu treatment in vitro. Thus, the NaBu-induced transcriptomic changes resembling the patterns of EOM SCs may contribute to the beneficial effects observed in G93A mice. More broadly, the distinct transcriptomic profile of EOM SCs may offer novel therapeutic targets to slow progressive neuromuscular functional decay in ALS and provide possible 'response biomarkers' in pre-clinical and clinical studies.
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Affiliation(s)
- Ang Li
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Jianxun Yi
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Xuejun Li
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Li Dong
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Lyle W Ostrow
- Department of Neurology, Lewis Katz School of Medicine at Temple UniversityPhiladelphiaUnited States
| | - Jianjie Ma
- Department of Surgery, Division of Surgical Sciences, University of VirginiaCharlottesvilleUnited States
| | - Jingsong Zhou
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
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2
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Leahy SN, Vita DJ, Broadie K. PTPN11/Corkscrew Activates Local Presynaptic Mapk Signaling to Regulate Synapsin, Synaptic Vesicle Pools, and Neurotransmission Strength, with a Dual Requirement in Neurons and Glia. J Neurosci 2024; 44:e1077232024. [PMID: 38471782 PMCID: PMC11044113 DOI: 10.1523/jneurosci.1077-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 03/01/2024] [Accepted: 03/05/2024] [Indexed: 03/14/2024] Open
Abstract
Cytoplasmic protein tyrosine phosphatase nonreceptor type 11 (PTPN11) and Drosophila homolog Corkscrew (Csw) regulate the mitogen-activated protein kinase (MAPK) pathway via a conserved autoinhibitory mechanism. Disease-causing loss-of-function (LoF) and gain-of-function (GoF) mutations both disrupt this autoinhibition to potentiate MAPK signaling. At the Drosophila neuromuscular junction glutamatergic synapse, LoF/GoF mutations elevate transmission strength and reduce activity-dependent synaptic depression. In both sexes of LoF/GoF mutations, the synaptic vesicles (SV)-colocalized synapsin phosphoprotein tether is highly elevated at rest, but quickly reduced with stimulation, suggesting a larger SV reserve pool with greatly heightened activity-dependent recruitment. Transmission electron microscopy of mutants reveals an elevated number of SVs clustered at the presynaptic active zones, suggesting that the increased vesicle availability is causative for the elevated neurotransmission. Direct neuron-targeted extracellular signal-regulated kinase (ERK) GoF phenocopies both increased local presynaptic MAPK/ERK signaling and synaptic transmission strength in mutants, confirming the presynaptic regulatory mechanism. Synapsin loss blocks this elevation in both presynaptic PTPN11 and ERK mutants. However, csw null mutants cannot be rescued by wild-type Csw in neurons: neurotransmission is only rescued by expressing Csw in both neurons and glia simultaneously. Nevertheless, targeted LoF/GoF mutations in either neurons or glia alone recapitulate the elevated neurotransmission. Thus, PTPN11/Csw mutations in either cell type are sufficient to upregulate presynaptic function, but a dual requirement in neurons and glia is necessary for neurotransmission. Taken together, we conclude that PTPN11/Csw acts in both neurons and glia, with LoF and GoF similarly upregulating MAPK/ERK signaling to enhance presynaptic Synapsin-mediated SV trafficking.
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Affiliation(s)
- Shannon N Leahy
- Departments of Biological Sciences, Vanderbilt University and Medical Center, Nashville, Tennessee 37235
| | - Dominic J Vita
- Departments of Biological Sciences, Vanderbilt University and Medical Center, Nashville, Tennessee 37235
| | - Kendal Broadie
- Departments of Biological Sciences, Vanderbilt University and Medical Center, Nashville, Tennessee 37235
- Cell and Developmental Biology, Vanderbilt University and Medical Center, Nashville, Tennessee 37235
- Pharmacology, Vanderbilt University and Medical Center, Nashville, Tennessee 37235
- Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, Tennessee 37235
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3
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Chang YC, Gao Y, Lee JY, Peng YJ, Langen J, Chang KT. Identification of secretory autophagy as a mechanism modulating activity-induced synaptic remodeling. Proc Natl Acad Sci U S A 2024; 121:e2315958121. [PMID: 38588427 PMCID: PMC11032469 DOI: 10.1073/pnas.2315958121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 02/23/2024] [Indexed: 04/10/2024] Open
Abstract
The ability of neurons to rapidly remodel their synaptic structure and strength in response to neuronal activity is highly conserved across species and crucial for complex brain functions. However, mechanisms required to elicit and coordinate the acute, activity-dependent structural changes across synapses are not well understood, as neurodevelopment and structural plasticity are tightly linked. Here, using an RNAi screen in Drosophila against genes affecting nervous system functions in humans, we uncouple cellular processes important for synaptic plasticity and synapse development. We find mutations associated with neurodegenerative and mental health disorders are 2-times more likely to affect activity-induced synaptic remodeling than synapse development. We report that while both synapse development and activity-induced synaptic remodeling at the fly NMJ require macroautophagy (hereafter referred to as autophagy), bifurcation in the autophagy pathway differentially impacts development and synaptic plasticity. We demonstrate that neuronal activity enhances autophagy activation but diminishes degradative autophagy, thereby driving the pathway towards autophagy-based secretion. Presynaptic knockdown of Snap29, Sec22, or Rab8, proteins implicated in the secretory autophagy pathway, is sufficient to abolish activity-induced synaptic remodeling. This study uncovers secretory autophagy as a transsynaptic signaling mechanism modulating synaptic plasticity.
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Affiliation(s)
- Yen-Ching Chang
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA90033
| | - Yuan Gao
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA90033
| | - Joo Yeun Lee
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA90033
| | - Yi-Jheng Peng
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA90033
| | - Jennifer Langen
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA90033
| | - Karen T. Chang
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA90033
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA90033
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Soreq H. Novel single-nucleus transcriptomics unravels developmental and functionally controlled principles of mammalian neuromuscular junctions. J Neurochem 2024; 168:339-341. [PMID: 37942848 DOI: 10.1111/jnc.15986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 09/27/2023] [Accepted: 09/27/2023] [Indexed: 11/10/2023]
Abstract
Prof Ohno's team (Ohkawara et al. 2023, current issue) underscored the dynamic and functional features that co-shape the embryonic and early post-natal development of mammalian neuromuscular junctions (NMJs) using single-nucleus transcriptomics which provides specific insights into the activities of individually studied nuclei and their functional characteristics. Unlike other single-nucleus transcriptomics studies, which tend to be limited to single developmental time points, this article provides novel views of the complex developmental and regulatory dynamics and embryonic cell type origins underscoring the formation of functioning mammalian NMJs by combining this transcriptomic approach with interference tests in cultured C2C12 myotubes. This reveals intriguing novel links between the particular nicotinic acetylcholine receptor genes (nAChR) and regulator transcripts thereof and enables outlining the sequential development of functioning NMJs along embryogenesis and soon after delivery. Specifically, the timewise and cell type origins of the studied nuclei emerged as essential for NMJ neurogenesis and inter-cellular transfer of specific regulators has been indicated. Breaking the barriers between distinct research subdisciplines, this study opens new neurochemistry research directions that recombine developmental, regulatory, and functional transcriptomics in NMJ-including tissues. Moreover, these findings may facilitate tests of diverse pharmaceutical and therapeutic modulators of neuromuscular functioning in health and disease, assisting the translational research progress in treating devastating neuromuscular states such as in amyotrophic lateral sclerosis, myasthenia gravis or individuals poisoned occupationally or otherwise with anticholinesterase inhibitors.
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Affiliation(s)
- Hermona Soreq
- The Hebrew University of Jerusalem, Jerusalem, Israel
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5
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Lundt S, Zhang N, Polo-Parada L, Wang X, Ding S. Dietary NMN supplementation enhances motor and NMJ function in ALS. Exp Neurol 2024; 374:114698. [PMID: 38266764 DOI: 10.1016/j.expneurol.2024.114698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/15/2024] [Accepted: 01/20/2024] [Indexed: 01/26/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disease that causes the degeneration of motor neurons in the motor cortex and spinal cord. Patients with ALS experience muscle weakness and atrophy in the limbs which eventually leads to paralysis and death. NAD+ is critical for energy metabolism, such as glycolysis and oxidative phosphorylation, but is also involved in non-metabolic cellular reactions. In the current study, we determined whether the supplementation of nicotinamide mononucleotide (NMN), an NAD+ precursor, in the diet had beneficial impacts on disease progression using a SOD1G93A mouse model of ALS. We found that the ALS mice fed with an NMN-supplemented diet (ALS+NMN mice) had modestly extended lifespan and exhibited delayed motor dysfunction. Using electrophysiology, we studied the effect of NMN on synaptic transmission at neuromuscular junctions (NMJs) in symptomatic of ALS mice (18 weeks old). ALS+NMN mice had larger end-plate potential (EPP) amplitudes and maintained better responses than ALS mice, and also had restored EPP facilitation. While quantal content was not affected by NMN, miniature EPP (mEPP) amplitude and frequency were elevated in ALS+NMN mice. NMN supplementation in diet also improved NMJ morphology, innervation, mitochondrial structure, and reduced reactive astrogliosis in the ventral horn of the lumbar spinal cord. Overall, our results indicate that dietary consumption of NMN can slow motor impairment, enhance NMJ function and improve healthspan of ALS mice.
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Affiliation(s)
- Samuel Lundt
- Interdisciplinary Neuroscience Program, University of Missouri, Columbia, MO 65211, United States of America; Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, United States of America
| | - Nannan Zhang
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, United States of America
| | - Luis Polo-Parada
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, United States of America; Department of Medical, Physiology and Pharmacology, University of Missouri, Columbia, MO 65211, United States of America
| | - Xinglong Wang
- Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, United States of America
| | - Shinghua Ding
- Interdisciplinary Neuroscience Program, University of Missouri, Columbia, MO 65211, United States of America; Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, United States of America; Department of Chemical and Biomedical Engineering, University of Missouri, Columbia, MO 65211, United States of America.
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Ohkawara B, Kurokawa M, Kanai A, Imamura K, Chen G, Zhang R, Masuda A, Higashi K, Mori H, Suzuki Y, Kurokawa K, Ohno K. Transcriptome profile of subsynaptic myonuclei at the neuromuscular junction in embryogenesis. J Neurochem 2024; 168:342-354. [PMID: 37994470 DOI: 10.1111/jnc.16013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 10/26/2023] [Accepted: 11/03/2023] [Indexed: 11/24/2023]
Abstract
Skeletal muscle fiber is a large syncytium with multiple and evenly distributed nuclei. Adult subsynaptic myonuclei beneath the neuromuscular junction (NMJ) express specific genes, the products of which coordinately function in the maintenance of the pre- and post-synaptic regions. However, the gene expression profiles that promote the NMJ formation during embryogenesis remain largely unexplored. We performed single-nucleus RNA sequencing (snRNA-seq) analysis of embryonic and neonatal mouse diaphragms, and found that each myonucleus had a distinct transcriptome pattern during the NMJ formation. Among the previously reported NMJ-constituting genes, Dok7, Chrna1, and Chrnd are specifically expressed in subsynaptic myonuclei at E18.5. In the E18.5 diaphragm, ca. 10.7% of the myonuclei express genes for the NMJ formation (Dok7, Chrna1, and Chrnd) together with four representative β-catenin regulators (Amotl2, Ptprk, Fam53b, and Tcf7l2). Additionally, the temporal gene expression patterns of these seven genes are synchronized in differentiating C2C12 myoblasts. Amotl2 and Ptprk are expressed in the sarcoplasm, where β-catenin serves as a structural protein to organize the membrane-anchored NMJ structure. In contrast, Fam53b and Tcf7l2 are expressed in the myonucleus, where β-catenin serves as a transcriptional coactivator in Wnt/β-catenin signaling at the NMJ. In C2C12 myotubes, knockdown of Amotl2 or Ptprk markedly, and that of Fam53b and Tcf7l2 less efficiently, impair the clustering of acetylcholine receptors. In contrast, knockdown of Fam53b and Tcf7l2, but not of Amotl2 or Ptprk, impairs the gene expression of Slit2 encoding an axonal attractant for motor neurons, which is required for the maturation of motor nerve terminal. Thus, Amotl2 and Ptprk exert different roles at the NM compared to Fam53b and Tcf7l2. Additionally, Wnt ligands originating from the spinal motor neurons and the perichondrium/chondrocyte are likely to work remotely on the subsynaptic nuclei and the myotendinous junctional nuclei, respectively. We conclude that snRNA-seq analysis of embryonic/neonatal diaphragms reveal a novel coordinated expression profile especially in the Wnt/β-catenin signaling that regulate the formation of the embryonic NMJ.
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Affiliation(s)
- Bisei Ohkawara
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masaomi Kurokawa
- Department of Informatics, National Institute of Genetics, Shizuoka, Japan
| | - Akinori Kanai
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Kiyomi Imamura
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Guiying Chen
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Ruchen Zhang
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Akio Masuda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Koichi Higashi
- Department of Informatics, National Institute of Genetics, Shizuoka, Japan
| | - Hiroshi Mori
- Department of Informatics, National Institute of Genetics, Shizuoka, Japan
| | - Yutaka Suzuki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Ken Kurokawa
- Department of Informatics, National Institute of Genetics, Shizuoka, Japan
| | - Kinji Ohno
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Schellino R, Boido M, Vrijbloed JW, Fariello RG, Vercelli A. Synergistically Acting on Myostatin and Agrin Pathways Increases Neuromuscular Junction Stability and Endurance in Old Mice. Aging Dis 2024; 15:893-910. [PMID: 37548943 PMCID: PMC10917542 DOI: 10.14336/ad.2023.0713-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 07/13/2023] [Indexed: 08/08/2023] Open
Abstract
Sarcopenia is the primary cause of impaired motor performance in the elderly. The current prevailing approach to counteract such condition is increasing the muscle mass through inhibition of the myostatin system: however, this strategy only moderately improves muscular strength, not being able to sustain the innervation of the hypertrophic muscle per se, leading to a progressive worsening of motor performances. Thus, we proposed the administration of ActR-Fc-nLG3, a protein that combines the soluble activin receptor, a strong myostatin inhibitor, with the C-terminal agrin nLG3 domain. This compound has the potential of reinforcing neuro-muscular stability to the hypertrophic muscle. We previously demonstrated an enhancement of motor endurance and ACh receptor aggregation in young mice after ActR-Fc-nLG3 administration. Now we extended these observations by demonstrating that also in aged (2 years-old) mice, long-term administration of ActR-Fc-nLG3 increases in a sustained way both motor endurance and muscle strength, compared with ActR-Fc, a myostatin inhibitor, alone. Histological data demonstrate that the administration of this biological improves neuromuscular stability and fiber innervation maintenance, preventing muscle fiber atrophy and inducing only moderate hypertrophy. Moreover, at the postsynaptic site we observe an increased folding in the soleplate, a likely anatomical substrate for improved neurotransmission efficiency in the NMJ, that may lead to enhanced motor endurance. We suggest that ActR-Fc-nLG3 may become a valid option for treating sarcopenia and possibly other disorders of striatal muscles.
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Affiliation(s)
- Roberta Schellino
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, Turin 10126, Italy
- Neuroscience Institute Cavalieri Ottolenghi, University of Turin, Orbassano, 10043 Italy
| | - Marina Boido
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, Turin 10126, Italy
- Neuroscience Institute Cavalieri Ottolenghi, University of Turin, Orbassano, 10043 Italy
| | | | | | - Alessandro Vercelli
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, Turin 10126, Italy
- Neuroscience Institute Cavalieri Ottolenghi, University of Turin, Orbassano, 10043 Italy
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Smith IR, Hendricks EL, Latcheva NK, Marenda DR, Liebl FLW. The CHD Protein Kismet Restricts the Synaptic Localization of Cell Adhesion Molecules at the Drosophila Neuromuscular Junction. Int J Mol Sci 2024; 25:3074. [PMID: 38474321 PMCID: PMC10931923 DOI: 10.3390/ijms25053074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 03/01/2024] [Accepted: 03/05/2024] [Indexed: 03/14/2024] Open
Abstract
The appropriate expression and localization of cell surface cell adhesion molecules must be tightly regulated for optimal synaptic growth and function. How neuronal plasma membrane proteins, including cell adhesion molecules, cycle between early endosomes and the plasma membrane is poorly understood. Here we show that the Drosophila homolog of the chromatin remodeling enzymes CHD7 and CHD8, Kismet, represses the synaptic levels of several cell adhesion molecules. Neuroligins 1 and 3 and the integrins αPS2 and βPS are increased at kismet mutant synapses but Kismet only directly regulates transcription of neuroligin 2. Kismet may therefore regulate synaptic CAMs indirectly by activating transcription of gene products that promote intracellular vesicle trafficking including endophilin B (endoB) and/or rab11. Knock down of EndoB in all tissues or neurons increases synaptic FasII while knock down of EndoB in kis mutants does not produce an additive increase in FasII. In contrast, neuronal expression of Rab11, which is deficient in kis mutants, leads to a further increase in synaptic FasII in kis mutants. These data support the hypothesis that Kis influences the synaptic localization of FasII by promoting intracellular vesicle trafficking through the early endosome.
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Affiliation(s)
- Ireland R. Smith
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62025, USA
| | - Emily L. Hendricks
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62025, USA
| | - Nina K. Latcheva
- Department of Biology, Drexel University, 3141 Chestnut St., Philadelphia, PA 19104, USA (D.R.M.)
- Program in Molecular and Cellular Biology and Genetics, Drexel University College of Medicine, Philadelphia, PA 19104, USA
- Neurogenetics Program, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Daniel R. Marenda
- Department of Biology, Drexel University, 3141 Chestnut St., Philadelphia, PA 19104, USA (D.R.M.)
- Program in Molecular and Cellular Biology and Genetics, Drexel University College of Medicine, Philadelphia, PA 19104, USA
- Division of Biological Infrastructure, National Science Foundation, Alexandria, VA 22314, USA
| | - Faith L. W. Liebl
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62025, USA
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Sert O, Ding X, Zhang C, Mi R, Hoke A, Rasband MN. Postsynaptic β1 spectrin maintains Na + channels at the neuromuscular junction. J Physiol 2024; 602:1127-1145. [PMID: 38441922 PMCID: PMC10942750 DOI: 10.1113/jp285894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 02/13/2024] [Indexed: 03/16/2024] Open
Abstract
Spectrins function together with actin as obligatory subunits of the submembranous cytoskeleton. Spectrins maintain cell shape, resist mechanical forces, and stabilize ion channel and transporter protein complexes through binding to scaffolding proteins. Recently, pathogenic variants of SPTBN4 (β4 spectrin) were reported to cause both neuropathy and myopathy. Although the role of β4 spectrin in neurons is mostly understood, its function in skeletal muscle, another excitable tissue subject to large forces, is unknown. Here, using a muscle specific β4 spectrin conditional knockout mouse, we show that β4 spectrin does not contribute to muscle function. In addition, we show β4 spectrin is not present in muscle, indicating the previously reported myopathy associated with pathogenic SPTBN4 variants is neurogenic in origin. More broadly, we show that α2, β1 and β2 spectrins are found in skeletal muscle, with α2 and β1 spectrins being enriched at the postsynaptic neuromuscular junction (NMJ). Surprisingly, using muscle specific conditional knockout mice, we show that loss of α2 and β2 spectrins had no effect on muscle health, function or the enrichment of β1 spectrin at the NMJ. Muscle specific deletion of β1 spectrin also had no effect on muscle health, but, with increasing age, resulted in the loss of clustered NMJ Na+ channels. Together, our results suggest that muscle β1 spectrin functions independently of an associated α spectrin to maintain Na+ channel clustering at the postsynaptic NMJ. Furthermore, despite repeated exposure to strong forces and in contrast to neurons, muscles do not require spectrin cytoskeletons to maintain cell shape or integrity. KEY POINTS: The myopathy found in pathogenic human SPTBN4 variants (where SPTBN4 is the gene encoding β4 spectrin) is neurogenic in origin. β1 spectrin plays essential roles in maintaining the density of neuromuscular junction Nav1.4 Na+ channels. By contrast to the canonical view of spectrin organization and function, we show that β1 spectrin can function independently of an associated α spectrin. Despite the large mechanical forces experienced by muscle, we show that spectrins are not required for muscle cell integrity. This is in stark contrast to red blood cells and the axons of neurons.
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Affiliation(s)
- Ozlem Sert
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA 77030
| | - Xiaoyun Ding
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA 77030
| | - Chuansheng Zhang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA 77030
| | - Ruifa Mi
- Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Ahmet Hoke
- Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Matthew N. Rasband
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA 77030
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Ohkawara B, Tomita H, Inoue T, Zhang S, Kanbara S, Koshimizu H, Miyasaka Y, Takeda JI, Nishiwaki H, Nakashima H, Ito M, Masuda A, Ishiguro N, Ogi T, Ohno T, Imagama S, Ohno K. Calcitriol ameliorates motor deficits and prolongs survival of Chrne-deficient mouse, a model for congenital myasthenic syndrome, by inducing Rspo2. Neurotherapeutics 2024; 21:e00318. [PMID: 38233267 DOI: 10.1016/j.neurot.2024.e00318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 01/02/2024] [Accepted: 01/03/2024] [Indexed: 01/19/2024] Open
Abstract
Signal transduction at the neuromuscular junction (NMJ) is compromised in a diverse array of diseases including congenital myasthenic syndromes (CMS). Germline mutations in CHRNE encoding the acetylcholine receptor (AChR) ε subunit are the most common cause of CMS. An active form of vitamin D, calcitriol, binds to vitamin D receptor (VDR) and regulates gene expressions. We found that calcitriol enhanced MuSK phosphorylation, AChR clustering, and myotube twitching in co-cultured C2C12 myotubes and NSC34 motor neurons. RNA-seq analysis of co-cultured cells showed that calcitriol increased the expressions of Rspo2, Rapsn, and Dusp6. ChIP-seq of VDR revealed that VDR binds to a region approximately 15 kbp upstream to Rspo2. Biallelic deletion of the VDR-binding site of Rspo2 by CRISPR/Cas9 in C2C12 myoblasts/myotubes nullified the calcitriol-mediated induction of Rspo2 expression and MuSK phosphorylation. We generated Chrne knockout (Chrne KO) mouse by CRISPR/Cas9. Intraperitoneal administration of calcitriol markedly increased the number of AChR clusters, as well as the area, the intensity, and the number of synaptophysin-positive synaptic vesicles, in Chrne KO mice. In addition, calcitriol ameliorated motor deficits and prolonged survival of Chrne KO mice. In the skeletal muscle, calcitriol increased the gene expressions of Rspo2, Rapsn, and Dusp6. We propose that calcitriol is a potential therapeutic agent for CMS and other diseases with defective neuromuscular signal transmission.
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Affiliation(s)
- Bisei Ohkawara
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| | - Hiroyuki Tomita
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan; Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Taro Inoue
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan; Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shaochuan Zhang
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shunsuke Kanbara
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan; Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroyuki Koshimizu
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan; Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yuki Miyasaka
- Department of Genetics, Research Institute of Environmental Medicine (RIeM), Nagoya University, Nagoya, Japan
| | - Jun-Ichi Takeda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroshi Nishiwaki
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroaki Nakashima
- Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Mikako Ito
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Akio Masuda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Naoki Ishiguro
- Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tomoo Ogi
- Department of Genetics, Research Institute of Environmental Medicine (RIeM), Nagoya University, Nagoya, Japan
| | - Tamio Ohno
- Division of Experimental Animals, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shiro Imagama
- Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kinji Ohno
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan.
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11
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Wang J, Yu Z, Wang Y, Chen Y, Xiao L, Zong Y, Feng Q, Peng L, Zhang H, Liu C. Ethylene thiourea exposure induces neurobehavioral toxicity in zebrafish by disrupting axon growth and neuromuscular junctions. J Environ Sci (China) 2024; 137:108-119. [PMID: 37980000 DOI: 10.1016/j.jes.2022.11.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 11/20/2022] [Accepted: 11/21/2022] [Indexed: 11/20/2023]
Abstract
Ethylene thiourea (ETU) converted from ethylene bisdithiocarbamate (EBDC) fungicides has aroused great concern because of its prevalence and harmful effects. Although ETU-induced neurotoxicity has been reported, the potential mechanisms remain unclear. This study provided insights into its neurotoxic effects at environmentally relevant concentrations in zebrafish. Our findings showed that embryonic exposure to ETU decreased the hatch rate and delayed somite development. Furthermore, ETU treatment significantly reduced the dark velocity in the locomotion assay. The upregulated tendency of the mitogen-activated protein kinases (MAPK) pathway (mknk1, atf4, mapkapk3) screened by transcriptome analysis implied motor neuron degeneration, which was validated by subsequent morphological observation, as axon length and branches were truncated in the 62.5 µg/L ETU group. However, although the rescue experiment with a p38 MAPK inhibitor (SB203580) successfully ameliorated axon degeneration, it failed to reverse the locomotion behaviors. Further exploration of transcriptome data revealed the varied expression of presynaptic scaffold protein-related genes (pcloa, pclob, bsna), whose downregulation might impair the neuromuscular junction (NMJ). Therefore, we reasonably suspected that ETU-induced neurobehavioral deficits might result from the combined effects of the MAPK pathway and presynaptic proteins. Considering this, we highlighted the necessity to take precautions and early interventions for susceptible ETU-exposed populations.
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Affiliation(s)
- Jingming Wang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhiquan Yu
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yongfeng Wang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yuanyao Chen
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Lin Xiao
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yanjun Zong
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qiyuan Feng
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Lianqi Peng
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Huiping Zhang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Chunyan Liu
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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12
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Núñez-Carpintero I, Rigau M, Bosio M, O'Connor E, Spendiff S, Azuma Y, Topf A, Thompson R, 't Hoen PAC, Chamova T, Tournev I, Guergueltcheva V, Laurie S, Beltran S, Capella-Gutiérrez S, Cirillo D, Lochmüller H, Valencia A. Rare disease research workflow using multilayer networks elucidates the molecular determinants of severity in Congenital Myasthenic Syndromes. Nat Commun 2024; 15:1227. [PMID: 38418480 PMCID: PMC10902324 DOI: 10.1038/s41467-024-45099-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 01/15/2024] [Indexed: 03/01/2024] Open
Abstract
Exploring the molecular basis of disease severity in rare disease scenarios is a challenging task provided the limitations on data availability. Causative genes have been described for Congenital Myasthenic Syndromes (CMS), a group of diverse minority neuromuscular junction (NMJ) disorders; yet a molecular explanation for the phenotypic severity differences remains unclear. Here, we present a workflow to explore the functional relationships between CMS causal genes and altered genes from each patient, based on multilayer network community detection analysis of complementary biomedical information provided by relevant data sources, namely protein-protein interactions, pathways and metabolomics. Our results show that CMS severity can be ascribed to the personalized impairment of extracellular matrix components and postsynaptic modulators of acetylcholine receptor (AChR) clustering. This work showcases how coupling multilayer network analysis with personalized -omics information provides molecular explanations to the varying severity of rare diseases; paving the way for sorting out similar cases in other rare diseases.
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Affiliation(s)
- Iker Núñez-Carpintero
- Barcelona Supercomputing Center (BSC), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain
| | - Maria Rigau
- Barcelona Supercomputing Center (BSC), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Mattia Bosio
- Barcelona Supercomputing Center (BSC), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain
- Coordination Unit Spanish National Bioinformatics Institute (INB/ELIXIR-ES), Barcelona Supercomputing Center, Barcelona, Spain
| | - Emily O'Connor
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - Sally Spendiff
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Yoshiteru Azuma
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Department of Pediatrics, Aichi Medical University, Nagakute, Japan
| | - Ana Topf
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
- Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Rachel Thompson
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Peter A C 't Hoen
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Teodora Chamova
- Department of Neurology, Expert Centre for Hereditary Neurologic and Metabolic Disorders, Alexandrovska University Hospital, Medical University-Sofia, Sofia, Bulgaria
| | - Ivailo Tournev
- Department of Neurology, Expert Centre for Hereditary Neurologic and Metabolic Disorders, Alexandrovska University Hospital, Medical University-Sofia, Sofia, Bulgaria
- Department of Cognitive Science and Psychology, New Bulgarian University, Sofia, 1618, Bulgaria
| | - Velina Guergueltcheva
- Clinic of Neurology, University Hospital Sofiamed, Sofia University St. Kliment Ohridski, Sofia, Bulgaria
| | - Steven Laurie
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia, Spain
| | - Sergi Beltran
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona (UB), Barcelona, Spain
| | - Salvador Capella-Gutiérrez
- Barcelona Supercomputing Center (BSC), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain
- Coordination Unit Spanish National Bioinformatics Institute (INB/ELIXIR-ES), Barcelona Supercomputing Center, Barcelona, Spain
| | - Davide Cirillo
- Barcelona Supercomputing Center (BSC), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain.
| | - Hanns Lochmüller
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia, Spain
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, ON, Canada
- Department of Neuropediatrics and Muscle Disorders, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Alfonso Valencia
- Barcelona Supercomputing Center (BSC), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain
- Coordination Unit Spanish National Bioinformatics Institute (INB/ELIXIR-ES), Barcelona Supercomputing Center, Barcelona, Spain
- ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain
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13
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Chen BH, Lin ZY, Zeng XX, Jiang YH, Geng F. LRP4-related signalling pathways and their regulatory role in neurological diseases. Brain Res 2024; 1825:148705. [PMID: 38065285 DOI: 10.1016/j.brainres.2023.148705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/17/2023] [Accepted: 12/03/2023] [Indexed: 01/28/2024]
Abstract
The mechanism of action of low-density lipoprotein receptor related protein 4 (LRP4) is mediated largely via the Agrin-LRP4-MuSK signalling pathway in the nervous system. LRP4 contributes to the development of synapses in the peripheral nervous system (PNS). It interacts with signalling molecules such as the amyloid beta-protein precursor (APP) and the wingless type protein (Wnt). Its mechanisms of action are complex and mediated via interaction between the pre-synaptic motor neuron and post-synaptic muscle cell in the PNS, which enhances the development of the neuromuscular junction (NMJ). LRP4 may function differently in the central nervous system (CNS) than in the PNS, where it regulates ATP and glutamate release via astrocytes. It mayaffect the growth and development of the CNS by controlling the energy metabolism. LRP4 interacts with Agrin to maintain dendrite growth and density in the CNS. The goal of this article is to review the current studies involving relevant LRP4 signaling pathways in the nervous system. The review also discusses the clinical and etiological roles of LRP4 in neurological illnesses, such as myasthenia gravis, Alzheimer's disease and epilepsy. In this review, we provide a theoretical foundation for the pathogenesis and therapeutic application of LRP4 in neurologic diseases.
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Affiliation(s)
- Bai-Hui Chen
- Department of Physiology, Shantou University Medical College, Shantou 515041, China
| | - Ze-Yu Lin
- Department of Physiology, Shantou University Medical College, Shantou 515041, China
| | - Xiao-Xue Zeng
- Department of Physiology, Shantou University Medical College, Shantou 515041, China
| | - Yi-Han Jiang
- Department of Physiology, Shantou University Medical College, Shantou 515041, China
| | - Fei Geng
- Department of Physiology, Shantou University Medical College, Shantou 515041, China; Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou 515041, China.
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14
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Beckers CJ, Mrestani A, Komma F, Dannhäuser S. Versatile Endogenous Editing of GluRIIA in Drosophila melanogaster. Cells 2024; 13:323. [PMID: 38391936 PMCID: PMC10887371 DOI: 10.3390/cells13040323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/05/2024] [Accepted: 02/08/2024] [Indexed: 02/24/2024] Open
Abstract
Glutamate receptors at the postsynaptic side translate neurotransmitter release from presynapses into postsynaptic excitation. They play a role in many forms of synaptic plasticity, e.g., homeostatic scaling of the receptor field, activity-dependent synaptic plasticity and the induction of presynaptic homeostatic potentiation (PHP). The latter process has been extensively studied at Drosophila melanogaster neuromuscular junctions (NMJs). The genetic removal of the glutamate receptor subunit IIA (GluRIIA) leads to an induction of PHP at the synapse. So far, mostly imprecise knockouts of the GluRIIA gene have been utilized. Furthermore, mutated and tagged versions of GluRIIA have been examined in the past, but most of these constructs were not expressed under endogenous regulatory control or involved the mentioned imprecise GluRIIA knockouts. We performed CRISPR/Cas9-assisted gene editing at the endogenous locus of GluRIIA. This enabled the investigation of the endogenous expression pattern of GluRIIA using tagged constructs with an EGFP and an ALFA tag for super-resolution immunofluorescence imaging, including structured illumination microscopy (SIM) and direct stochastic optical reconstruction microscopy (dSTORM). All GluRIIA constructs exhibited full functionality and PHP could be induced by philanthotoxin at control levels. By applying hierarchical clustering algorithms to analyze the dSTORM data, we detected postsynaptic receptor cluster areas of ~0.15 µm2. Consequently, our constructs are suitable for ultrastructural analyses of GluRIIA.
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Affiliation(s)
- Constantin J. Beckers
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, D-97070 Würzburg, Germany
| | - Achmed Mrestani
- Department of Neurology, University of Leipzig Medical Center, D-04103 Leipzig, Germany;
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, D-04103 Leipzig, Germany
| | - Fabian Komma
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, D-97070 Würzburg, Germany
| | - Sven Dannhäuser
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, D-97070 Würzburg, Germany
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15
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Hann SH, Kim SY, Kim YL, Jo YW, Kang JS, Park H, Choi SY, Kong YY. Depletion of SMN protein in mesenchymal progenitors impairs the development of bone and neuromuscular junction in spinal muscular atrophy. eLife 2024; 12:RP92731. [PMID: 38318851 PMCID: PMC10945524 DOI: 10.7554/elife.92731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disorder characterized by the deficiency of the survival motor neuron (SMN) protein, which leads to motor neuron dysfunction and muscle atrophy. In addition to the requirement for SMN in motor neurons, recent studies suggest that SMN deficiency in peripheral tissues plays a key role in the pathogenesis of SMA. Using limb mesenchymal progenitor cell (MPC)-specific SMN-depleted mouse models, we reveal that SMN reduction in limb MPCs causes defects in the development of bone and neuromuscular junction (NMJ). Specifically, these mice exhibited impaired growth plate homeostasis and reduced insulin-like growth factor (IGF) signaling from chondrocytes, rather than from the liver. Furthermore, the reduction of SMN in fibro-adipogenic progenitors (FAPs) resulted in abnormal NMJ maturation, altered release of neurotransmitters, and NMJ morphological defects. Transplantation of healthy FAPs rescued the morphological deterioration. Our findings highlight the significance of mesenchymal SMN in neuromusculoskeletal pathogenesis of SMA and provide insights into potential therapeutic strategies targeting mesenchymal cells for the treatment of SMA.
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Affiliation(s)
- Sang-Hyeon Hann
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Seon-Yong Kim
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Republic of Korea
| | - Ye Lynne Kim
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Young-Woo Jo
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Jong-Seol Kang
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hyerim Park
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Se-Young Choi
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Republic of Korea
| | - Young-Yun Kong
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
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16
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Hörner SJ, Couturier N, Hafner M, Rudolf R. Schwann cells in neuromuscular in vitro models. Biol Chem 2024; 405:25-30. [PMID: 37357580 DOI: 10.1515/hsz-2023-0172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 06/16/2023] [Indexed: 06/27/2023]
Abstract
Neuromuscular cell culture models are used to investigate synapse formation and function, as well as mechanisms of de-and regeneration in neuromuscular diseases. Recent developments including 3D culture technique and hiPSC technology have propelled their ability to complement insights from in vivo models. However, most cultures have not considered Schwann cells, the glial part of NMJs. In the following, a brief overview of different types of neuromuscular cocultures is provided alongside examples for studies that included Schwann cells. From these, findings concerning the effects of Schwann cells on those cultures are summarized and future lines of research are proposed.
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Affiliation(s)
- Sarah Janice Hörner
- Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences, D-68163 Mannheim, Germany
- Interdisciplinary Center for Neurosciences, Heidelberg University, D-69117 Heidelberg, Germany
- Center for Mass Spectrometry and Optical Spectroscopy, Mannheim University of Applied Sciences, D-68163 Mannheim, Germany
| | - Nathalie Couturier
- Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences, D-68163 Mannheim, Germany
- Interdisciplinary Center for Neurosciences, Heidelberg University, D-69117 Heidelberg, Germany
- Center for Mass Spectrometry and Optical Spectroscopy, Mannheim University of Applied Sciences, D-68163 Mannheim, Germany
| | - Mathias Hafner
- Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences, D-68163 Mannheim, Germany
- Institute of Medical Technology, Heidelberg University and Mannheim University of Applied Sciences, D-69117 Heidelberg, Germany
| | - Rüdiger Rudolf
- Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences, D-68163 Mannheim, Germany
- Interdisciplinary Center for Neurosciences, Heidelberg University, D-69117 Heidelberg, Germany
- Center for Mass Spectrometry and Optical Spectroscopy, Mannheim University of Applied Sciences, D-68163 Mannheim, Germany
- Mannheim Center for Translational Neuroscience, Medical Faculty Mannheim Heidelberg University, D-68167 Mannheim, Germany
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17
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Gessler L, Huraskin D, Jian Y, Eiber N, Hu Z, Prószyński T, Hashemolhosseini S. The YAP1/TAZ-TEAD transcriptional network regulates gene expression at neuromuscular junctions in skeletal muscle fibers. Nucleic Acids Res 2024; 52:600-624. [PMID: 38048326 PMCID: PMC10810223 DOI: 10.1093/nar/gkad1124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 11/06/2023] [Accepted: 11/09/2023] [Indexed: 12/06/2023] Open
Abstract
We examined YAP1/TAZ-TEAD signaling pathway activity at neuromuscular junctions (NMJs) of skeletal muscle fibers in adult mice. Our investigations revealed that muscle-specific knockouts of Yap1 or Taz, or both, demonstrate that these transcriptional coactivators regulate synaptic gene expression, the number and morphology of NMJs, and synaptic nuclei. Yap1 or Taz single knockout mice display reduced grip strength, fragmentation of NMJs, and accumulation of synaptic nuclei. Yap1/Taz muscle-specific double knockout mice do not survive beyond birth and possess almost no NMJs, the few detectable show severely impaired morphology and are organized in widened endplate bands; and with motor nerve endings being mostly absent. Myogenic gene expression is significantly impaired in the denervated muscles of knockout mice. We found that Tead1 and Tead4 transcription rates were increased upon incubation of control primary myotubes with AGRN-conditioned medium. Reduced AGRN-dependent acetylcholine receptor clustering and synaptic gene transcription were observed in differentiated primary Tead1 and Tead4 knockout myotubes. In silico analysis of previously reported genomic occupancy sites of TEAD1/4 revealed evolutionary conserved regions of potential TEAD binding motifs in key synaptic genes, the relevance of which was functionally confirmed by reporter assays. Collectively, our data suggest a role for YAP1/TAZ-TEAD1/TEAD4 signaling, particularly through TAZ-TEAD4, in regulating synaptic gene expression and acetylcholine receptor clustering at NMJs.
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Affiliation(s)
- Lea Gessler
- Institute of Biochemistry, Medical Faculty, Friedrich-Alexander-University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Danyil Huraskin
- Institute of Biochemistry, Medical Faculty, Friedrich-Alexander-University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Yongzhi Jian
- Institute of Biochemistry, Medical Faculty, Friedrich-Alexander-University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Nane Eiber
- Institute of Biochemistry, Medical Faculty, Friedrich-Alexander-University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Zhaoyong Hu
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Tomasz J Prószyński
- Łukasiewicz Research Network-PORT Polish Center for Technology Development, Wrocław, Poland
| | - Said Hashemolhosseini
- Institute of Biochemistry, Medical Faculty, Friedrich-Alexander-University of Erlangen-Nürnberg, 91054 Erlangen, Germany
- Muscle Research Center, Friedrich-Alexander-University of Erlangen-Nürnberg, 91054 Erlangen, Germany
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18
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Sugimoto T, Sakamaki C, Kimura T, Eguchi T, Miura S, Kamei Y. Peroxisome proliferator-activated receptor γ coactivator 1α regulates downstream of tyrosine kinase-7 (Dok-7) expression important for neuromuscular junction formation. Sci Rep 2024; 14:1780. [PMID: 38245592 PMCID: PMC10799880 DOI: 10.1038/s41598-024-52198-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 01/15/2024] [Indexed: 01/22/2024] Open
Abstract
The neuromuscular junction (NMJ)-formed between a motor nerve terminal and skeletal muscle fiber-plays an important role in muscle contraction and other muscle functions. Aging and neurodegeneration worsen NMJ formation and impair muscle function. Downstream of tyrosine kinase-7 (Dok-7), expressed in skeletal muscle fibers, is essential for the formation of NMJ. Exercise increases the expression of the transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) in skeletal muscles and restores NMJ formation. In this study, we used skeletal muscle-specific PGC1α knockout or overexpression mice to examine the role of PGC1α in regulating Dok-7 expression and NMJ formation. Our findings revealed that Dok-7 expression is regulated by PGC1α, and luciferase activity of the Dok-7 promoter is greatly increased by coexpressing PGC1α and estrogen receptor-related receptor α. Thus, we suggest PGC1α is involved in exercise-mediated restoration of NMJ formation.
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Affiliation(s)
- Takumi Sugimoto
- Laboratory of Molecular Nutrition, Graduate School of Environmental and Life Science, Kyoto Prefectural University, Kyoto, Japan
| | - Chihiro Sakamaki
- Laboratory of Molecular Nutrition, Graduate School of Environmental and Life Science, Kyoto Prefectural University, Kyoto, Japan
| | - Tokushi Kimura
- Laboratory of Molecular Nutrition, Graduate School of Environmental and Life Science, Kyoto Prefectural University, Kyoto, Japan
| | - Takahiro Eguchi
- Brain-Skeletal Muscle Connection in Aging Project Team, Geroscience Research Center, National Center for Geriatrics and Gerontology, Aichi, Japan
| | - Shinji Miura
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
| | - Yasutomi Kamei
- Laboratory of Molecular Nutrition, Graduate School of Environmental and Life Science, Kyoto Prefectural University, Kyoto, Japan.
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19
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Miao Y, Xie L, Song J, Cai X, Yang J, Ma X, Chen S, Xie P. Unraveling the causes of sarcopenia: Roles of neuromuscular junction impairment and mitochondrial dysfunction. Physiol Rep 2024; 12:e15917. [PMID: 38225199 PMCID: PMC10789655 DOI: 10.14814/phy2.15917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/11/2023] [Accepted: 12/22/2023] [Indexed: 01/17/2024] Open
Abstract
Sarcopenia is a systemic skeletal muscle disease characterized by a decline in skeletal muscle mass and function. Originally defined as an age-associated condition, sarcopenia presently also encompasses muscular atrophy due to various pathological factors, such as intensive care unit-acquired weakness, inactivity, and malnutrition. The exact pathogenesis of sarcopenia is still unknown; herein, we review the pathological roles of the neuromuscular junction and mitochondria in this condition. Sarcopenia is caused by complex and interdependent pathophysiological mechanisms, including aging, neuromuscular junction impairment, mitochondrial dysfunction, insulin resistance, lipotoxicity, endocrine factors, oxidative stress, and inflammation. Among these, neuromuscular junction instability and mitochondrial dysfunction are particularly significant. Dysfunction in neuromuscular junction can lead to muscle weakness or paralysis. Mitochondria, which are plentiful in neurons and muscle fibers, play an important role in neuromuscular junction transmission. Therefore, impairments in both mitochondria and neuromuscular junction may be one of the key pathophysiological mechanisms leading to sarcopenia. Moreover, this article explores the structural and functional alterations in the neuromuscular junction and mitochondria in sarcopenia, suggesting that a deeper understanding of these changes could provide valuable insights for the prevention or treatment of sarcopenia.
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Affiliation(s)
- Yanmei Miao
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi)Zunyi Medical UniversityZunyiChina
| | - Leiyu Xie
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi)Zunyi Medical UniversityZunyiChina
| | - Jiamei Song
- Department of Nursing of Affiliated HospitalZunyi Medical UniversityZunyiChina
| | - Xing Cai
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi)Zunyi Medical UniversityZunyiChina
| | - Jinghe Yang
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi)Zunyi Medical UniversityZunyiChina
- Department of The First Clinical CollegeZunyi Medical UniversityZunyiChina
| | - Xinglong Ma
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi)Zunyi Medical UniversityZunyiChina
| | - Shaolin Chen
- Department of Nursing of Affiliated HospitalZunyi Medical UniversityZunyiChina
| | - Peng Xie
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi)Zunyi Medical UniversityZunyiChina
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20
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Chakravorty A, Sheeba V, Manjithaya R. Drosophila melanogaster Neuromuscular Junction as a Model to Study Synaptopathies and Neuronal Autophagy. Methods Mol Biol 2024; 2761:97-120. [PMID: 38427233 DOI: 10.1007/978-1-0716-3662-6_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Neuronal synapse dysfunction is a key characteristic of several neurodegenerative disorders, such as Alzheimer's disease, spinocerebellar ataxias, and Huntington's disease. Modeling these disorders to study synaptic dysfunction requires a robust and reproducible method for assaying the subtle changes associated with synaptopathies in terms of structure and function of the synapses. Drosophila melanogaster neuromuscular junctions (NMJs) serve as good models to study such alterations. Further, modifications in the microenvironment of synapses can sometimes reflect in the behavior of the animal, which can also be assayed in a high-throughput manner. The methods outlined in this chapter highlight assays to study the behavioral changes associated with synaptic dysfunction in a spinocerebellar ataxia type 3 (SCA3) model. Further, molecular assessment of alterations in NMJ structure and function is also summarized, followed by effects of autophagy pathway upregulation in providing neuroprotection. These methods can be further extended and modified to study the therapeutic effects of drugs or small molecules in providing neuroprotection for any synaptopathy models.
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Affiliation(s)
- Anushka Chakravorty
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Vasu Sheeba
- Chronobiology and Behavioural Neurogenetics Laboratory, Neuroscience Unit, Bangalore, India.
| | - Ravi Manjithaya
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India.
- Chronobiology and Behavioural Neurogenetics Laboratory, Neuroscience Unit, Bangalore, India.
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21
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Tannemaat MR, Huijbers MG, Verschuuren JJGM. Myasthenia gravis-Pathophysiology, diagnosis, and treatment. Handb Clin Neurol 2024; 200:283-305. [PMID: 38494283 DOI: 10.1016/b978-0-12-823912-4.00026-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Myasthenia gravis (MG) is an autoimmune disease characterized by dysfunction of the neuromuscular junction resulting in skeletal muscle weakness. It is equally prevalent in males and females, but debuts at a younger age in females and at an older age in males. Ptosis, diplopia, facial bulbar weakness, and limb weakness are the most common symptoms. MG can be classified based on the presence of serum autoantibodies. Acetylcholine receptor (AChR) antibodies are found in 80%-85% of patients, muscle-specific kinase (MuSK) antibodies in 5%-8%, and <1% may have low-density lipoprotein receptor-related protein 4 (Lrp4) antibodies. Approximately 10% of patients are seronegative for antibodies binding the known disease-related antigens. In patients with AChR MG, 10%-20% have a thymoma, which is usually detected at the onset of the disease. Important differences between clinical presentation, treatment responsiveness, and disease mechanisms have been observed between these different serologic MG classes. Besides the typical clinical features and serologic testing, the diagnosis can be established with additional tests, including repetitive nerve stimulation, single fiber EMG, and the ice pack test. Treatment options for MG consist of symptomatic treatment (such as pyridostigmine), immunosuppressive treatment, or thymectomy. Despite the treatment with symptomatic drugs, steroid-sparing immunosuppressants, intravenous immunoglobulins, plasmapheresis, and thymectomy, a large proportion of patients remain chronically dependent on corticosteroids (CS). In the past decade, the number of treatment options for MG has considerably increased. Advances in the understanding of the pathophysiology have led to new treatment options targeting B or T cells, the complement cascade, the neonatal Fc receptor or cytokines. In the future, these new treatments are likely to reduce the chronic use of CS, diminish side effects, and decrease the number of patients with refractory disease.
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Affiliation(s)
- Martijn R Tannemaat
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Maartje G Huijbers
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands; Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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22
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Tarasova E, Bogacheva P, Chernyshev K, Balezina O. Quantal size increase induced by the endocannabinoid 2-arachidonoylglycerol requires activation of CGRP receptors in mouse motor synapses. Synapse 2024; 78:e22281. [PMID: 37694983 DOI: 10.1002/syn.22281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 08/22/2023] [Accepted: 08/24/2023] [Indexed: 09/12/2023]
Abstract
In mouse motor synapses, the exogenous application of the endocannabinoid (EC) 2-arachidonoylglycerol (2-AG) increases acetylcholine (ACh) quantal size due to the activation of CB1 receptors and the stimulation of ACh vesicular uptake. In the present study, microelectrode recordings of miniature endplate potentials (MEPP) revealed that this effect of 2-AG is independent of brain-derived neurotrophic factor (BDNF) signaling but involves the activation of calcitonin gene-related peptide (CGRP) receptors along with CB1 receptors. Potentiation of MEPP amplitude in the presence of 2-AG was prevented by blockers of CGRP receptors and ryanodine receptors (RyR) and by inhibitors of phospholipase C (PLC) and Ca2+ /calmodulin-dependent protein kinase II (CaMKII). Therefore, we suggest a hypothetical chain of events, which starts from the activation of presynaptic CB1 receptors, involves PLC, RyR, and CaMKII, and results in CGRP release with the subsequent activation of presynaptic CGRP receptors. Activation of CGRP receptors is probably a part of a complex molecular cascade leading to the 2-AG-induced increase in ACh quantal size and MEPP amplitude. We propose that the same chain of events may also take place if 2-AG is endogenously produced in mouse motor synapses, because the increase in MEPP amplitude that follows after prolonged tetanic muscle contractions (30 Hz, 2 min) was prevented by the blocking of CB1 receptors. This work may help to unveil the previously unknown aspects of the functional interaction between ECs and peptide modulators aimed at the regulation of quantal size and synaptic transmission.
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Affiliation(s)
- Ekaterina Tarasova
- Department of Human and Animal Physiology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Polina Bogacheva
- Department of Human and Animal Physiology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Kirill Chernyshev
- Department of Human and Animal Physiology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Olga Balezina
- Department of Human and Animal Physiology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russian Federation
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Chen X, Qiu J, Gao Z, Liu B, Zhang C, Yu W, Yang J, Shen Y, Qi L, Yao X, Sun H, Yang X. Myasthenia gravis: Molecular mechanisms and promising therapeutic strategies. Biochem Pharmacol 2023; 218:115872. [PMID: 37865142 DOI: 10.1016/j.bcp.2023.115872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 10/23/2023]
Abstract
Myasthenia gravis (MG) is a type of autoimmune disease caused by the blockage of neuromuscular junction transmission owing to the attack of autoantibodies on transmission-related proteins. Related antibodies, such as anti-AChR, anti-MuSK and anti-LRP4 antibodies, can be detected in most patients with MG. Although traditional therapies can control most symptoms, several challenges remain to be addressed, necessitating the development of more effective and safe treatment strategies for MG. With the in-depth exploration on the mechanism and immune targets of MG, effective therapies, especially therapies using biologicals, have been reported recently. Given the important roles of immune cells, cytokines and intercellular interactions in the pathological process of MG, B-cell targeted therapy, T-cell targeted therapy, proteasome inhibitors targeting plasma cell, complement inhibitors, FcRn inhibitors have been developed for the treatment of MG. Although these novel therapies exert good therapeutic effects, they may weaken the immunity and increase the risk of infection in MG patients. This review elaborates on the pathogenesis of MG and discusses the advantages and disadvantages of the strategies of traditional treatment and biologicals. In addition, this review emphasises that combined therapy may have better therapeutic effects and reducing the risk of side effects of treatments, which has great prospects for the treatment of MG. With the deepening of research on immunotherapy targets in MG, novel opportunities and challenges in the treatment of MG will be introduced.
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Affiliation(s)
- Xin Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Jiayi Qiu
- Department of Clinical Medicine, Medical College, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Zihui Gao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Boya Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Chen Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Weiran Yu
- Department of Clinical Medicine, Medical College, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Jiawen Yang
- Department of Clinical Medicine, Medical College, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Yuntian Shen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Lei Qi
- Department of Emergency Medicine, Affiliated Hospital of Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Xinlei Yao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China.
| | - Hualin Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China.
| | - Xiaoming Yang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China.
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Soustelle L, Aimond F, López-Andrés C, Brugioti V, Raoul C, Layalle S. ALS-Associated KIF5A Mutation Causes Locomotor Deficits Associated with Cytoplasmic Inclusions, Alterations of Neuromuscular Junctions, and Motor Neuron Loss. J Neurosci 2023; 43:8058-8072. [PMID: 37748861 PMCID: PMC10669773 DOI: 10.1523/jneurosci.0562-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 09/12/2023] [Accepted: 09/13/2023] [Indexed: 09/27/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting motor neurons. Recently, genome-wide association studies identified KIF5A as a new ALS-causing gene. KIF5A encodes a protein of the kinesin-1 family, allowing the anterograde transport of cargos along the microtubule rails in neurons. In ALS patients, mutations in the KIF5A gene induce exon 27 skipping, resulting in a mutated protein with a new C-terminal region (KIF5A Δ27). To understand how KIF5A Δ27 underpins the disease, we developed an ALS-associated KIF5A Drosophila model. When selectively expressed in motor neurons, KIF5A Δ27 alters larval locomotion as well as morphology and synaptic transmission at neuromuscular junctions in both males and females. We show that the distribution of mitochondria and synaptic vesicles is profoundly disturbed by KIF5A Δ27 expression. That is consistent with the numerous KIF5A Δ27-containing inclusions observed in motor neuron soma and axons. Moreover, KIF5A Δ27 expression leads to motor neuron death and reduces life expectancy. Our in vivo model reveals that a toxic gain of function underlies the pathogenicity of ALS-linked KIF5A mutant.SIGNIFICANCE STATEMENT Understanding how a mutation identified in patients with amyotrophic lateral sclerosis (ALS) causes the disease and the loss of motor neurons is crucial to fight against this disease. To this end, we have created a Drosophila model based on the motor neuron expression of the KIF5A mutant gene, recently identified in ALS patients. KIF5A encodes a kinesin that allows the anterograde transport of cargos. This model recapitulates the main features of ALS, including alterations of locomotion, synaptic neurotransmission, and morphology at neuromuscular junctions, as well as motor neuron death. KIF5A mutant is found in cytoplasmic inclusions, and its pathogenicity is because of a toxic gain of function.
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Affiliation(s)
- Laurent Soustelle
- Institute for Neurosciences Montpellier, Université Montpellier, Institut National de la Santé et de la Recherche Médicale, Montpellier, 34091, France
| | - Franck Aimond
- Institute for Neurosciences Montpellier, Université Montpellier, Institut National de la Santé et de la Recherche Médicale, Montpellier, 34091, France
| | - Cristina López-Andrés
- Institute for Neurosciences Montpellier, Université Montpellier, Institut National de la Santé et de la Recherche Médicale, Montpellier, 34091, France
| | - Véronique Brugioti
- Institute for Neurosciences Montpellier, Université Montpellier, Institut National de la Santé et de la Recherche Médicale, Montpellier, 34091, France
| | - Cédric Raoul
- Institute for Neurosciences Montpellier, Université Montpellier, Institut National de la Santé et de la Recherche Médicale, Montpellier, 34091, France
| | - Sophie Layalle
- Institute for Neurosciences Montpellier, Université Montpellier, Institut National de la Santé et de la Recherche Médicale, Montpellier, 34091, France
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25
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Shaheen A, Richter Gorey CL, Sghaier A, Dason JS. Cholesterol is required for activity-dependent synaptic growth. J Cell Sci 2023; 136:jcs261563. [PMID: 37902091 DOI: 10.1242/jcs.261563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 10/24/2023] [Indexed: 10/31/2023] Open
Abstract
Changes in cholesterol content of neuronal membranes occur during development and brain aging. Little is known about whether synaptic activity regulates cholesterol levels in neuronal membranes and whether these changes affect neuronal development and function. We generated transgenic flies that express the cholesterol-binding D4H domain of perfringolysin O toxin and found increased levels of cholesterol in presynaptic terminals of Drosophila larval neuromuscular junctions following increased synaptic activity. Reduced cholesterol impaired synaptic growth and largely prevented activity-dependent synaptic growth. Presynaptic knockdown of adenylyl cyclase phenocopied the impaired synaptic growth caused by reducing cholesterol. Furthermore, the effects of knocking down adenylyl cyclase and reducing cholesterol were not additive, suggesting that they function in the same pathway. Increasing cAMP levels using a dunce mutant with reduced phosphodiesterase activity failed to rescue this impaired synaptic growth, suggesting that cholesterol functions downstream of cAMP. We used a protein kinase A (PKA) sensor to show that reducing cholesterol levels reduced presynaptic PKA activity. Collectively, our results demonstrate that enhanced synaptic activity increased cholesterol levels in presynaptic terminals and that these changes likely activate the cAMP-PKA pathway during activity-dependent growth.
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Affiliation(s)
- Amber Shaheen
- Department of Biomedical Sciences, University of Windsor, Windsor, Ontario, N9B 3P4, Canada
| | - Claire L Richter Gorey
- Department of Biomedical Sciences, University of Windsor, Windsor, Ontario, N9B 3P4, Canada
| | - Adam Sghaier
- Department of Biomedical Sciences, University of Windsor, Windsor, Ontario, N9B 3P4, Canada
| | - Jeffrey S Dason
- Department of Biomedical Sciences, University of Windsor, Windsor, Ontario, N9B 3P4, Canada
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26
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Barbeau S, Semprez F, Dobbertin A, Merriadec L, Roussange F, Eymard B, Sternberg D, Fournier E, Karasoy H, Martinat C, Legay C. Molecular Analysis of a Congenital Myasthenic Syndrome Due to a Pathogenic Variant Affecting the C-Terminus of ColQ. Int J Mol Sci 2023; 24:16217. [PMID: 38003406 PMCID: PMC10671321 DOI: 10.3390/ijms242216217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/04/2023] [Accepted: 11/04/2023] [Indexed: 11/26/2023] Open
Abstract
Congenital Myasthenic Syndromes (CMSs) are rare inherited diseases of the neuromuscular junction characterized by muscle weakness. CMSs with acetylcholinesterase deficiency are due to pathogenic variants in COLQ, a collagen that anchors the enzyme at the synapse. The two COLQ N-terminal domains have been characterized as being biochemical and functional. They are responsible for the structure of the protein in the triple helix and the association of COLQ with acetylcholinesterase. To deepen the analysis of the distal C-terminal peptide properties and understand the CMSs associated to pathogenic variants in this domain, we have analyzed the case of a 32 year old male patient bearing a homozygote splice site variant c.1281 C > T that changes the sequence of the last 28 aa in COLQ. Using COS cell and mouse muscle cell expression, we show that the COLQ variant does not impair the formation of the collagen triple helix in these cells, nor its association with acetylcholinesterase, and that the hetero-oligomers are secreted. However, the interaction of COLQ variant with LRP4, a signaling hub at the neuromuscular junction, is decreased by 44% as demonstrated by in vitro biochemical methods. In addition, an increase in all acetylcholine receptor subunit mRNA levels is observed in muscle cells derived from the patient iPSC. All these approaches point to pathophysiological mechanisms essentially characterized by a decrease in signaling and the presence of immature acetylcholine receptors.
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Affiliation(s)
- Susie Barbeau
- CNRS, Saint Pères Paris Institute for the Neurosciences (SPPIN), Université Paris Cité, 75270 Paris, France
| | - Fannie Semprez
- CNRS, Saint Pères Paris Institute for the Neurosciences (SPPIN), Université Paris Cité, 75270 Paris, France
| | - Alexandre Dobbertin
- CNRS, Saint Pères Paris Institute for the Neurosciences (SPPIN), Université Paris Cité, 75270 Paris, France
| | - Laurine Merriadec
- INSERM/UEPS UMR 861, Université Paris Saclay, I-STEM, 91100 Corbeil-Essonnes, France
| | - Florine Roussange
- INSERM/UEPS UMR 861, Université Paris Saclay, I-STEM, 91100 Corbeil-Essonnes, France
| | - Bruno Eymard
- Inserm U 1127, CNRS UMR 7225, Sorbonne Université Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle Épinière, ICM, Sorbonne Université, 75013 Paris, France
- AP-HP, Hôpital Pitié-Salpêtrière, 75013 Paris, France
| | - Damien Sternberg
- Inserm U 1127, CNRS UMR 7225, Sorbonne Université Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle Épinière, ICM, Sorbonne Université, 75013 Paris, France
- AP-HP, Hôpital Pitié-Salpêtrière, 75013 Paris, France
| | - Emmanuel Fournier
- Department of Physiology, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, 75006 Paris, France
| | - Hanice Karasoy
- Department of Neurology, Faculty of Medicine, Ege University, Izmir 35100, Turkey
| | - Cécile Martinat
- INSERM/UEPS UMR 861, Université Paris Saclay, I-STEM, 91100 Corbeil-Essonnes, France
| | - Claire Legay
- CNRS, Saint Pères Paris Institute for the Neurosciences (SPPIN), Université Paris Cité, 75270 Paris, France
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Imomnazarov K, Torrence SE, Lindgren CA. Reduced Plasma-Membrane Calcium ATPase Activity and Extracellular Acidification Trigger Presynaptic Homeostatic Potentiation at the Mouse Neuromuscular Junction. Neuroscience 2023; 532:103-112. [PMID: 37778690 DOI: 10.1016/j.neuroscience.2023.09.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 08/23/2023] [Accepted: 09/24/2023] [Indexed: 10/03/2023]
Abstract
At the vertebrate neuromuscular junction (NMJ), presynaptic homeostatic potentiation (PHP) refers to an increase in neurotransmitter release that restores the strength of synaptic transmission following a blockade of nicotinic acetylcholine receptors (nAChRs). Mechanisms informing the presynaptic terminal of the loss of postsynaptic receptivity remain poorly understood. Previous research at the mouse NMJ suggests that extracellular protons may function as a retrograde signal that triggers an upregulation of neurotransmitter output (measured by quantal content, QC) through the activation of acid-sensing ion channels (ASICs). We further investigated the pH-dependency of PHP in an ex-vivo mouse muscle preparation. We observed that increasing the buffering capacity of the perfusion saline with HEPES abolishes PHP and that acidifying the saline from pH 7.4 to pH 7.2-7.1 increases QC, demonstrating the necessity and sufficiency of extracellular acidification for PHP. We then sought to uncover how the blockade of nAChRs leads to the pH decrease. Plasma-membrane calcium ATPase (PMCA), a calcium-proton antiporter, is known to alkalize the synaptic cleft following neurotransmission in a calcium-dependent manner. We hypothesize that since nAChR blockade reduces postsynaptic calcium entry, it also reduces the alkalizing activity of the PMCA, thereby causing acidosis, ASIC activation, and QC upregulation. In line with this hypothesis, we found that pharmacological inhibition of the PMCA with carboxyeosin induces QC upregulation and that this effect requires functional ASICs. We also demonstrated that muscles pre-treated with carboxyeosin fail to generate PHP. These findings suggest that reduced PMCA activity causes presynaptic homeostatic potentiation by activating ASICs at the mouse NMJ.
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Affiliation(s)
| | - Sarah E Torrence
- Department of Biology, Grinnell College, Grinnell, IA 50112, United States
| | - Clark A Lindgren
- Department of Biology, Grinnell College, Grinnell, IA 50112, United States.
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28
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Ozawa Y, Uzawa A, Onishi Y, Yasuda M, Kojima Y, Kuwabara S. Activation of the classical complement pathway in myasthenia gravis with acetylcholine receptor antibodies. Muscle Nerve 2023; 68:798-804. [PMID: 37705312 DOI: 10.1002/mus.27973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 08/20/2023] [Accepted: 08/23/2023] [Indexed: 09/15/2023]
Abstract
INTRODUCTION/AIMS Myasthenia gravis (MG) is an autoimmune disease affecting the neuromuscular junction (NMJ) of skeletal muscle. Complement activation is one of the mechanisms by which anti-acetylcholine receptor (anti-AChR) autoantibodies reduce synaptic transmission at the NMJ. In this study, we aimed to examine the activation of the complement pathways, including the classical pathway, as potential contributors to the pathogenesis of MG with anti-AChR antibodies. METHODS In this single-center, observational study of 45 patients with anti-AChR-antibody-positive generalized MG, serum concentrations of major components of the complement pathways, including C1q, C5, C5a, soluble C5b-9 (sC5b-9), Ba, and complement factor H, were measured using an enzyme-linked immunosorbent assay. A total of 25 patients with a non-inflammatory neurological disorder served as controls. In addition, the relationships of complement activation with clinical characteristics were examined. RESULTS The patients with MG exhibited lower serum levels of C5 (p = .0001) and higher serum levels of sC5b-9 (p = .004) compared with the control group. At about 6 months (range, 172-209 days) after the start of immunotherapy, serum levels of Ba were significantly higher than baseline levels (p = .002) and were associated with improvement in MG clinical scores. DISCUSSION Herein, we provide evidence for the activation of the classical complement pathway and its association with disease activity in anti-AChR-antibody-positive generalized MG.
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Affiliation(s)
- Yukiko Ozawa
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Akiyuki Uzawa
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Yosuke Onishi
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Manato Yasuda
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Yuta Kojima
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
- Department of Neurology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Satoshi Kuwabara
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
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29
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Aimino MA, Humenik J, Parisi MJ, Duhart JC, Mosca TJ. SynLight: a bicistronic strategy for simultaneous active zone and cell labeling in the Drosophila nervous system. G3 (Bethesda) 2023; 13:jkad221. [PMID: 37757863 PMCID: PMC10627267 DOI: 10.1093/g3journal/jkad221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 07/14/2023] [Accepted: 09/17/2023] [Indexed: 09/29/2023]
Abstract
At synapses, chemical neurotransmission mediates the exchange of information between neurons, leading to complex movement, behaviors, and stimulus processing. The immense number and variety of neurons within the nervous system make discerning individual neuron populations difficult, necessitating the development of advanced neuronal labeling techniques. In Drosophila, Bruchpilot-Short and mCD8-GFP, which label presynaptic active zones and neuronal membranes, respectively, have been widely used to study synapse development and organization. This labeling is often achieved via the expression of 2 independent constructs by a single binary expression system, but expression can weaken when multiple transgenes are expressed by a single driver. Recent work has sought to circumvent these drawbacks by developing methods that encode multiple proteins from a single transcript. Self-cleaving peptides, specifically 2A peptides, have emerged as effective sequences for accomplishing this task. We leveraged 2A ribosomal skipping peptides to engineer a construct that produces both Bruchpilot-Short-mStraw and mCD8-GFP from the same mRNA, which we named SynLight. Using SynLight, we visualized the putative synaptic active zones and membranes of multiple classes of olfactory, visual, and motor neurons and observed the correct separation of signal, confirming that both proteins are being generated separately. Furthermore, we demonstrate proof of principle by quantifying synaptic puncta number and neurite volume in olfactory neurons and finding no difference between the synapse densities of neurons expressing SynLight or neurons expressing both transgenes separately. At the neuromuscular junction, we determined that the synaptic puncta number labeled by SynLight was comparable to the endogenous puncta labeled by antibody staining. Overall, SynLight is a versatile tool for examining synapse density in any nervous system region of interest and allows new questions to be answered about synaptic development and organization.
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Affiliation(s)
- Michael A Aimino
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Jesse Humenik
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Michael J Parisi
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Juan Carlos Duhart
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Timothy J Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
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30
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Zakirjanova GF, Giniatullin AR, Gafurova CR, Malomouzh AI, Fedorov NS, Khaziev AN, Tsentsevitsky AN, Petrov AM. Effects of cholesterol oxidase on neurotransmission and acetylcholine levels at the mice neuromuscular junctions. Arch Biochem Biophys 2023; 749:109803. [PMID: 37955112 DOI: 10.1016/j.abb.2023.109803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/20/2023] [Accepted: 10/27/2023] [Indexed: 11/14/2023]
Abstract
Membrane cholesterol oxidation is a hallmark of redox and metabolic imbalance, and it may accompany neurodegenerative disorders. Using microelectrode recordings of postsynaptic responses as well as fluorescent dyes for monitoring synaptic vesicle cycling and membrane properties, the action of enzymatic cholesterol oxidation on neuromuscular transmission was studied in the mice diaphragms. Cholesterol oxidase (ChO) at low concentration disturbed lipid-ordering specifically in the synaptic membranes, but it did not change markedly spontaneous exocytosis and evoked release in response to single stimuli. At low external Ca2+ conditions, analysis of single exocytotic events revealed a decrease in minimal synaptic delay and the probability of exocytosis upon plasmalemmal cholesterol oxidation. At moderate- and high-frequency activity, ChO treatment enhanced both neurotransmitter and FM-dye release. Furthermore, it precluded a change in exocytotic mode from full-fusion to kiss-and-run during high-frequency stimulation. Accumulation of extracellular acetylcholine (without stimulation) dependent on vesamicol-sensitive transporters was suppressed by ChO. The effects of plasmalemmal cholesterol oxidation on both neurotransmitter/dye release at intense activity and external acetylcholine levels were reversed when synaptic vesicle membranes were also exposed to ChO (i.e., the enzyme treatment was combined with induction of exo-endocytotic cycling). Thus, we suggest that plasmalemmal cholesterol oxidation affects exocytotic machinery functioning, enhances synaptic vesicle recruitment to the exocytosis and decreases extracellular neurotransmitter levels at rest, whereas ChO acting on synaptic vesicle membranes suppresses the participation of the vesicles in the subsequent exocytosis and increases the neurotransmitter leakage. The mechanisms underlying ChO action can be related to the lipid raft disruption.
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Affiliation(s)
- Guzalia F Zakirjanova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St, Kazan, 420111, RT, Russia; Kazan State Medical University, 49 Butlerova St., Kazan, 420012, RT, Russia
| | - Arthur R Giniatullin
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St, Kazan, 420111, RT, Russia; Kazan State Medical University, 49 Butlerova St., Kazan, 420012, RT, Russia
| | - Chulpan R Gafurova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St, Kazan, 420111, RT, Russia; Kazan State Medical University, 49 Butlerova St., Kazan, 420012, RT, Russia
| | - Artem I Malomouzh
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St, Kazan, 420111, RT, Russia; Kazan National Research Technical University, 10, K. Marx Street, Kazan, 420111, Russia
| | - Nikita S Fedorov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St, Kazan, 420111, RT, Russia
| | - Arthur N Khaziev
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St, Kazan, 420111, RT, Russia
| | - Andrei N Tsentsevitsky
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St, Kazan, 420111, RT, Russia
| | - Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St, Kazan, 420111, RT, Russia; Kazan State Medical University, 49 Butlerova St., Kazan, 420012, RT, Russia; Kazan Federal University, 18 Kremlyovskaya Street, Kazan, 420008, Russia.
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31
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Zhang S, Wang X, Liu Z, Jin S, Mao CX. Using Drosophila Larval Neuromuscular Junction and Muscle Cells to Visualize Microtubule Network. J Vis Exp 2023. [PMID: 37929978 DOI: 10.3791/65774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023] Open
Abstract
The microtubule network is an essential component of the nervous system. Mutations in many microtubules regulatory proteins are associated with neurodevelopmental disorders and neurological diseases, such as microtubule-associated protein Tau to neurodegenerative diseases, microtubule severing protein Spastin and Katanin 60 cause hereditary spastic paraplegia and neurodevelopmental abnormalities, respectively. Detection of microtubule networks in neurons is advantageous for elucidating the pathogenesis of neurological disorders. However, the small size of neurons and the dense arrangement of axonal microtubule bundles make visualizing the microtubule networks challenging. In this study, we describe a method for dissection of the larval neuromuscular junction and muscle cells, as well as immunostaining of α-tubulin and microtubule-associated protein Futsch to visualize microtubule networks in Drosophila melanogaster. The neuromuscular junction permits us to observe both pre-and post-synaptic microtubules, and the large size of muscle cells in Drosophila larva allows for clear visualization of the microtubule network. Here, by mutating and overexpressing Katanin 60 in Drosophila melanogaster, and then examining the microtubule networks in the neuromuscular junction and muscle cells, we accurately reveal the regulatory role of Katanin 60 in neurodevelopment. Therefore, combined with the powerful genetic tools of Drosophila melanogaster, this protocol greatly facilitates genetic screening and microtubule dynamics analysis for the role of microtubule network regulatory proteins in the nervous system.
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Affiliation(s)
- Shengquan Zhang
- National & Local Joint Engineering Research Center of High-throughput Drug Screening Technology, School of life science, Hubei University
| | - Xiongxiong Wang
- National & Local Joint Engineering Research Center of High-throughput Drug Screening Technology, School of life science, Hubei University
| | - Zhihua Liu
- National & Local Joint Engineering Research Center of High-throughput Drug Screening Technology, School of life science, Hubei University
| | - Shan Jin
- National & Local Joint Engineering Research Center of High-throughput Drug Screening Technology, School of life science, Hubei University;
| | - Chuan-Xi Mao
- National & Local Joint Engineering Research Center of High-throughput Drug Screening Technology, School of life science, Hubei University;
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Gao H, Zhao Z, Li J, Guo Z, Zhang F, Wang K, Bai X, Wang Q, Guan Y, Wang Y, Zhang P, Lv N, Zhu H, Li Z. Platelet-rich plasma promotes skeletal muscle regeneration and neuromuscular functional reconstitution in a concentration-dependent manner in a rat laceration model. Biochem Biophys Res Commun 2023; 672:185-192. [PMID: 37354612 DOI: 10.1016/j.bbrc.2023.05.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Accepted: 05/30/2023] [Indexed: 06/26/2023]
Abstract
Abnormal function of injured muscle with innervation loss is a challenge in sports medicine. The difficulty of rehabilitation is regenerating and reconstructing the skeletal muscle tissue and the neuromuscular junction (NMJ). Platelet-rich plasma (PRP) releases various growth factors that may provide an appropriate niche for tissue regeneration. However, the specific mechanism of the PRP's efficacy on muscle healing remains unknown. In this study, we injected PRP with different concentration gradients (800, 1200, 1600 × 109 pl/L) or saline into a rat gastrocnemius laceration model. The results of histopathology and neuromyography show that PRP improved myofibers regeneration, facilitated electrophysiological recovery, and reduced fibrosis in a concentration-dependent manner. Furthermore, we found that PRP promotes the activity of satellite cells by upregulating the expression of the myogenic regulatory factor (MyoD, myogenin). Meanwhile, PRP promotes the regeneration and maturation of acetylcholine receptor (AChR) clusters of the Neuromuscular junction (NMJ) on the regenerative myofibers. Finally, we found that the expression of the Agrin, LRP4, and MuSK was upregulated in the PRP-treated groups, which may contribute to AChR cluster regeneration and functional recovery. The conclusions proposed a hypothesis for PRP treatment's efficacy and mechanism in muscle injuries, indicating promising application prospects.
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Affiliation(s)
- Huayi Gao
- Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China; Beijing Institute of Radiation Medicine, No. 27 Taiping Road, Haidian District, Beijing, 100850, China.
| | - Zhidong Zhao
- Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China; Beijing Institute of Radiation Medicine, No. 27 Taiping Road, Haidian District, Beijing, 100850, China.
| | - Ji Li
- Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China; Beijing Institute of Radiation Medicine, No. 27 Taiping Road, Haidian District, Beijing, 100850, China.
| | - Zheng Guo
- Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China; Beijing Institute of Radiation Medicine, No. 27 Taiping Road, Haidian District, Beijing, 100850, China.
| | - Fei Zhang
- Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China.
| | - Ketao Wang
- Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China.
| | - Xiaowei Bai
- Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China.
| | - Qi Wang
- Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China.
| | - Yu Guan
- Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China.
| | - Yaoting Wang
- Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China.
| | - Pengli Zhang
- Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China.
| | - Ningyu Lv
- Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China.
| | - Heng Zhu
- Beijing Institute of Radiation Medicine, No. 27 Taiping Road, Haidian District, Beijing, 100850, China.
| | - Zhongli Li
- Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China.
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Liao X, Wang Y, Lai X, Wang S. The role of Rapsyn in neuromuscular junction and congenital myasthenic syndrome. Biomol Biomed 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Sharma B, Roy A, Sengupta T, Vishwakarma LC, Singh A, Netam R, Nag TC, Akhtar N, Mallick HN. Acute sleep deprivation induces synaptic remodeling at the soleus muscle neuromuscular junction in rats. Sleep 2023; 46:zsac229. [PMID: 36130235 DOI: 10.1093/sleep/zsac229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 08/03/2022] [Indexed: 07/26/2023] Open
Abstract
Sleep is important for cognitive and physical performance. Sleep deprivation not only affects neural functions but also results in muscular fatigue. A good night's sleep reverses these functional derangements caused by sleep deprivation. The role of sleep in brain function has been extensively studied. However, its role in neuromuscular junction (NMJ) or skeletal muscle morphology is sparsely addressed although skeletal muscle atonia and suspended thermoregulation during rapid eye movement sleep possibly provide a conducive environment for the muscle to rest and repair; somewhat similar to slow-wave sleep for synaptic downscaling. In the present study, we have investigated the effect of 24 h sleep deprivation on the NMJ morphology and neurochemistry using electron microscopy and immunohistochemistry in the rat soleus muscle. Acute sleep deprivation altered synaptic ultra-structure viz. mitochondria, synaptic vesicle, synaptic proteins, basal lamina, and junctional folds needed for neuromuscular transmission. Further acute sleep deprivation showed the depletion of the neurotransmitter acetylcholine and the overactivity of its degrading enzyme acetylcholine esterase at the NMJ. The impact of sleep deprivation on synaptic homeostasis in the brain has been extensively reported recently. The present evidence from our studies shows new information on the role of sleep on the NMJ homeostasis and its functioning.
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Affiliation(s)
- Binney Sharma
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| | - Avishek Roy
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| | - Trina Sengupta
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
- Department of Physiology, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
| | | | - Anuraag Singh
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India
| | - Ritesh Netam
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| | - Tapas Chandra Nag
- Department of Physiology, Faculty of Medicine & Health Sciences, SGT University, Gurugram, Haryana, India
| | - Nasreen Akhtar
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| | - Hruda Nanda Mallick
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
- Department of Physiology, Faculty of Medicine & Health Sciences, SGT University, Gurugram, Haryana, India
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35
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Durbin RJ, Heredia DJ, Gould TW, Renden RB. Postsynaptic Calcium Extrusion at the Mouse Neuromuscular Junction Alkalinizes the Synaptic Cleft. J Neurosci 2023; 43:5741-5752. [PMID: 37474311 PMCID: PMC10423045 DOI: 10.1523/jneurosci.0815-23.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/07/2023] [Accepted: 07/14/2023] [Indexed: 07/22/2023] Open
Abstract
Neurotransmission is shaped by extracellular pH. Alkalization enhances pH-sensitive transmitter release and receptor activation, whereas acidification inhibits these processes and can activate acid-sensitive conductances in the synaptic cleft. Previous work has shown that the synaptic cleft can either acidify because of synaptic vesicular release and/or alkalize because of Ca2+ extrusion by the plasma membrane ATPase (PMCA). The direction of change differs across synapse types. At the mammalian neuromuscular junction (NMJ), the direction and magnitude of pH transients in the synaptic cleft during transmission remain ambiguous. We set out to elucidate the extracellular pH transients that occur at this cholinergic synapse under near-physiological conditions and identify their sources. We monitored pH-dependent changes in the synaptic cleft of the mouse levator auris longus using viral expression of the pseudoratiometric probe pHusion-Ex in the muscle. Using mice from both sexes, a significant and prolonged alkalization occurred when stimulating the connected nerve for 5 s at 50 Hz, which was dependent on postsynaptic intracellular Ca2+ release. Sustained stimulation for a longer duration (20 s at 50 Hz) caused additional prolonged net acidification at the cleft. To investigate the mechanism underlying cleft alkalization, we used muscle-expressed GCaMP3 to monitor the contribution of postsynaptic Ca2+ Activity-induced liberation of intracellular Ca2+ in muscle positively correlated with alkalization of the synaptic cleft, whereas inhibiting PMCA significantly decreased the extent of cleft alkalization. Thus, cholinergic synapses of the mouse NMJ typically alkalize because of cytosolic Ca2+ liberated in muscle during activity, unless under highly strenuous conditions where acidification predominates.SIGNIFICANCE STATEMENT Changes in synaptic cleft pH alter neurotransmission, acting on receptors and channels on both sides of the synapse. Synaptic acidification has been associated with a myriad of diseases in the central and peripheral nervous system. Here, we report that in near-physiological recording conditions the cholinergic neuromuscular junction shows use-dependent bidirectional changes in synaptic cleft pH-immediate alkalinization and a long-lasting acidification under prolonged stimulation. These results provide further insight into physiologically relevant changes at cholinergic synapses that have not been defined previously. Understanding and identifying synaptic pH transients during and after neuronal activity provides insight into short-term synaptic plasticity synapses and may identify therapeutic targets for diseases.
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Affiliation(s)
- Ryan J Durbin
- Integrative Neuroscience Graduate Program, University of Nevada, Reno, Reno, Nevada 89557
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557
| | - Dante J Heredia
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557
| | - Thomas W Gould
- Integrative Neuroscience Graduate Program, University of Nevada, Reno, Reno, Nevada 89557
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557
| | - Robert B Renden
- Integrative Neuroscience Graduate Program, University of Nevada, Reno, Reno, Nevada 89557
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557
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Li L, Chen S, Yokoyama H, Kaburagi H, Hirai T, Tsuji K, Enomoto M, Wakabayashi Y, Okawa A. Remodeling of Neuromuscular Junctions in Target Muscle Following Nerve Regeneration in Mice After Delayed Peripheral Nerve Repair. Neuroscience 2023; 524:197-208. [PMID: 37201862 DOI: 10.1016/j.neuroscience.2023.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 05/05/2023] [Accepted: 05/10/2023] [Indexed: 05/20/2023]
Abstract
Peripheral nerve injury (PNI) induces severe functional loss in extremities. Progressive denervation and atrophy occur in the muscles if the nerve repair is delayed for long periods of the time. To overcome these difficulties, detailed mechanisms should be determined for neuromuscular junction (NMJ) degeneration in target muscles after PNI and regeneration after nerve repair. We established two models of end-to-end neurorrhaphy and allogeneic nerve grafting in the chronic phase after common peroneal nerve injury in female mice (n = 100 in total). We evaluated motor function, histology, and gene expression in the target muscles during their regeneration processes and compared the models. We found that the functional recovery with allogeneic nerve grafting was superior to that with end-to-end neurorrhaphy, and the number of reinnervated NMJs and Schwann cells was increased at 12 weeks after allograft. In addition, NMJ- and Schwann cell-related molecules showed high expression in the target muscle in the allograft model. These results suggest that Schwann cell migrating from the allograft might play a crucial role in nerve regeneration in the chronic phase after PNI. The relationship between the NMJ and Schwann cells should be further investigated in the target muscle.
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Affiliation(s)
- Leyang Li
- Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo, Tokyo 113-8519, Japan; Department of Traumatic Orthopaedics, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China.
| | - Su Chen
- Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo, Tokyo 113-8519, Japan.
| | - Hiroyuki Yokoyama
- Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo, Tokyo 113-8519, Japan.
| | - Hidetoshi Kaburagi
- Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo, Tokyo 113-8519, Japan.
| | - Takashi Hirai
- Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo, Tokyo 113-8519, Japan.
| | - Kunikazu Tsuji
- Department of Cartilage Regeneration, Tokyo Medical and Dental University, Tokyo, Japan.
| | - Mitsuhiro Enomoto
- Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo, Tokyo 113-8519, Japan.
| | - Yoshiaki Wakabayashi
- Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo, Tokyo 113-8519, Japan.
| | - Atsushi Okawa
- Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo, Tokyo 113-8519, Japan.
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37
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Uyen Dao TM, Barbeau S, Messéant J, Della-Gaspera B, Bouceba T, Semprez F, Legay C, Dobbertin A. The collagen ColQ binds to LRP4 and regulates the activation of the Muscle-Specific Kinase-LRP4 receptor complex by agrin at the neuromuscular junction. J Biol Chem 2023; 299:104962. [PMID: 37356721 PMCID: PMC10382678 DOI: 10.1016/j.jbc.2023.104962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/09/2023] [Accepted: 06/13/2023] [Indexed: 06/27/2023] Open
Abstract
Collagen Q (ColQ) is a nonfibrillar collagen that plays a crucial role at the vertebrate neuromuscular junction (NMJ) by anchoring acetylcholinesterase to the synapse. ColQ also functions in signaling, as it regulates acetylcholine receptor clustering and synaptic gene expression, in a manner dependent on muscle-specific kinase (MuSK), a key protein in NMJ formation and maintenance. MuSK forms a complex with low-density lipoprotein receptor-related protein 4 (LRP4), its coreceptor for the proteoglycan agrin at the NMJ. Previous studies suggested that ColQ also interacts with MuSK. However, the molecular mechanisms underlying ColQ functions and ColQ-MuSK interaction have not been fully elucidated. Here, we investigated whether ColQ binds directly to MuSK and/or LRP4 and whether it modulates agrin-mediated MuSK-LRP4 activation. Using coimmunoprecipitation, pull-down, plate-binding assays, and surface plasmon resonance, we show that ColQ binds directly to LRP4 but not to MuSK and that ColQ interacts indirectly with MuSK through LRP4. In addition, we show that the LRP4 N-terminal region, which contains the agrin-binding sites, is also crucial for ColQ binding to LRP4. Moreover, ColQ-LRP4 interaction was reduced in the presence of agrin, suggesting that agrin and ColQ compete for binding to LRP4. Strikingly, we reveal ColQ has two opposing effects on agrin-induced MuSK-LRP4 signaling: it constitutively reduces MuSK phosphorylation levels in agrin-stimulated myotubes but concomitantly increases MuSK accumulation at the muscle cell surface. Our results identify LRP4 as a major receptor of ColQ and provide new insights into mechanisms of ColQ signaling and acetylcholinesterase anchoring at the NMJ.
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Affiliation(s)
- Thi Minh Uyen Dao
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Susie Barbeau
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Julien Messéant
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | | | - Tahar Bouceba
- Sorbonne Université, CNRS, IBPS, Protein Engineering Platform, Paris, France
| | - Fannie Semprez
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Claire Legay
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Alexandre Dobbertin
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France.
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38
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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: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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He K, Han Y, Li X, Hernandez RX, Riboul DV, Feghhi T, Justs KA, Mahneva O, Perry S, Macleod GT, Dickman D. Physiologic and Nanoscale Distinctions Define Glutamatergic Synapses in Tonic vs Phasic Neurons. J Neurosci 2023; 43:4598-4611. [PMID: 37221096 PMCID: PMC10286941 DOI: 10.1523/jneurosci.0046-23.2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 05/05/2023] [Accepted: 05/11/2023] [Indexed: 05/25/2023] Open
Abstract
Neurons exhibit a striking degree of functional diversity, each one tuned to the needs of the circuitry in which it is embedded. A fundamental functional dichotomy occurs in activity patterns, with some neurons firing at a relatively constant "tonic" rate, while others fire in bursts, a "phasic" pattern. Synapses formed by tonic versus phasic neurons are also functionally differentiated, yet the bases of their distinctive properties remain enigmatic. A major challenge toward illuminating the synaptic differences between tonic and phasic neurons is the difficulty in isolating their physiological properties. At the Drosophila neuromuscular junction, most muscle fibers are coinnervated by two motor neurons: the tonic "MN-Ib" and phasic "MN-Is." Here, we used selective expression of a newly developed botulinum neurotoxin transgene to silence tonic or phasic motor neurons in Drosophila larvae of either sex. This approach highlighted major differences in their neurotransmitter release properties, including probability, short-term plasticity, and vesicle pools. Furthermore, Ca2+ imaging demonstrated ∼2-fold greater Ca2+ influx at phasic neuron release sites relative to tonic, along with an enhanced synaptic vesicle coupling. Finally, confocal and super-resolution imaging revealed that phasic neuron release sites are organized in a more compact arrangement, with enhanced stoichiometry of voltage-gated Ca2+ channels relative to other active zone scaffolds. These data suggest that distinctions in active zone nano-architecture and Ca2+ influx collaborate to differentially tune glutamate release at tonic versus phasic synaptic subtypes.SIGNIFICANCE STATEMENT "Tonic" and "phasic" neuronal subtypes, based on differential firing properties, are common across many nervous systems. Using a recently developed approach to selectively silence transmission from one of these two neurons, we reveal specialized synaptic functional and structural properties that distinguish these specialized neurons. This study provides important insights into how input-specific synaptic diversity is achieved, which could have implications for neurologic disorders that involve changes in synaptic function.
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Affiliation(s)
- Kaikai He
- Department of Neurobiology, University of Southern California, Los Angeles, California 90089
- USC Neuroscience Graduate Program, Los Angeles, California 90089
| | - Yifu Han
- Department of Neurobiology, University of Southern California, Los Angeles, California 90089
- USC Neuroscience Graduate Program, Los Angeles, California 90089
| | - Xiling Li
- Department of Neurobiology, University of Southern California, Los Angeles, California 90089
- USC Neuroscience Graduate Program, Los Angeles, California 90089
| | - Roberto X Hernandez
- Integrative Biology and Neuroscience Graduate Program, Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida 33431
- International Max Planck Research School for Brain and Behavior, Jupiter, Florida 33458
| | - Danielle V Riboul
- Integrative Biology Graduate Program, Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida 33431
| | - Touhid Feghhi
- Department of Physics, Florida Atlantic University, Boca Raton, Florida 33431
| | - Karlis A Justs
- Integrative Biology and Neuroscience Graduate Program, Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida 33431
| | - Olena Mahneva
- Wilkes Honors College, Florida Atlantic University, Jupiter, Florida 33458
| | - Sarah Perry
- Department of Neurobiology, University of Southern California, Los Angeles, California 90089
| | - Gregory T Macleod
- Wilkes Honors College, Florida Atlantic University, Jupiter, Florida 33458
- Institute for Human Health and Disease Intervention, Florida Atlantic University, Jupiter, Florida 33458
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, California 90089
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40
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Xie T, Xu G, Liu Y, Quade B, Lin W, Bai XC. Structural insights into the assembly of the agrin/LRP4/MuSK signaling complex. Proc Natl Acad Sci U S A 2023; 120:e2300453120. [PMID: 37252960 PMCID: PMC10266037 DOI: 10.1073/pnas.2300453120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/02/2023] [Indexed: 06/01/2023] Open
Abstract
MuSK is a receptor tyrosine kinase (RTK) that plays essential roles in the formation and maintenance of the neuromuscular junction. Distinct from most members of RTK family, MuSK activation requires not only its cognate ligand agrin but also its coreceptors LRP4. However, how agrin and LRP4 coactivate MuSK remains unclear. Here, we report the cryo-EM structure of the extracellular ternary complex of agrin/LRP4/MuSK in a stoichiometry of 1:1:1. This structure reveals that arc-shaped LRP4 simultaneously recruits both agrin and MuSK to its central cavity, thereby promoting a direct interaction between agrin and MuSK. Our cryo-EM analyses therefore uncover the assembly mechanism of agrin/LRP4/MuSK signaling complex and reveal how MuSK receptor is activated by concurrent binding of agrin and LRP4.
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Affiliation(s)
- Tian Xie
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Guangjun Xu
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Yun Liu
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Bradley Quade
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Weichun Lin
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Xiao-chen Bai
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX75390
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Mukhamedyarov MA, Khabibrakhmanov AN, Khuzakhmetova VF, Giniatullin AR, Zakirjanova GF, Zhilyakov NV, Mukhutdinova KA, Samigullin DV, Grigoryev PN, Zakharov AV, Zefirov AL, Petrov AM. Early Alterations in Structural and Functional Properties in the Neuromuscular Junctions of Mutant FUS Mice. Int J Mol Sci 2023; 24:9022. [PMID: 37240370 PMCID: PMC10218837 DOI: 10.3390/ijms24109022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/16/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is manifested as skeletal muscle denervation, loss of motor neurons and finally severe respiratory failure. Mutations of RNA-binding protein FUS are one of the common genetic reasons of ALS accompanied by a 'dying back' type of degeneration. Using fluorescent approaches and microelectrode recordings, the early structural and functional alterations in diaphragm neuromuscular junctions (NMJs) were studied in mutant FUS mice at the pre-onset stage. Lipid peroxidation and decreased staining with a lipid raft marker were found in the mutant mice. Despite the preservation of the end-plate structure, immunolabeling revealed an increase in levels of presynaptic proteins, SNAP-25 and synapsin 1. The latter can restrain Ca2+-dependent synaptic vesicle mobilization. Indeed, neurotransmitter release upon intense nerve stimulation and its recovery after tetanus and compensatory synaptic vesicle endocytosis were markedly depressed in FUS mice. There was a trend to attenuation of axonal [Ca2+]in increase upon nerve stimulation at 20 Hz. However, no changes in neurotransmitter release and the intraterminal Ca2+ transient in response to low frequency stimulation or in quantal content and the synchrony of neurotransmitter release at low levels of external Ca2+ were detected. At a later stage, shrinking and fragmentation of end plates together with a decrease in presynaptic protein expression and disturbance of the neurotransmitter release timing occurred. Overall, suppression of synaptic vesicle exo-endocytosis upon intense activity probably due to alterations in membrane properties, synapsin 1 levels and Ca2+ kinetics could be an early sign of nascent NMJ pathology, which leads to neuromuscular contact disorganization.
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Affiliation(s)
- Marat A. Mukhamedyarov
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
| | - Aydar N. Khabibrakhmanov
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
| | - Venera F. Khuzakhmetova
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center ‘‘Kazan Scientific Center of RAS”, 2/31 Lobachevsky St., P.O. Box 30, Kazan 420111, Russia (N.V.Z.)
| | - Arthur R. Giniatullin
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center ‘‘Kazan Scientific Center of RAS”, 2/31 Lobachevsky St., P.O. Box 30, Kazan 420111, Russia (N.V.Z.)
| | - Guzalia F. Zakirjanova
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center ‘‘Kazan Scientific Center of RAS”, 2/31 Lobachevsky St., P.O. Box 30, Kazan 420111, Russia (N.V.Z.)
| | - Nikita V. Zhilyakov
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center ‘‘Kazan Scientific Center of RAS”, 2/31 Lobachevsky St., P.O. Box 30, Kazan 420111, Russia (N.V.Z.)
| | - Kamilla A. Mukhutdinova
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
| | - Dmitry V. Samigullin
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center ‘‘Kazan Scientific Center of RAS”, 2/31 Lobachevsky St., P.O. Box 30, Kazan 420111, Russia (N.V.Z.)
- Department of Radiophotonics and Microwave Technologies, Kazan National Research Technical University, 10 K. Marx St., Kazan 420111, Russia
| | - Pavel N. Grigoryev
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
| | - Andrey V. Zakharov
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
- Laboratory of Neurobiology, Kazan Federal University, Kazan 420008, Russia
| | - Andrey L. Zefirov
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
| | - Alexey M. Petrov
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova St., Kazan 420012, Russia; (M.A.M.)
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center ‘‘Kazan Scientific Center of RAS”, 2/31 Lobachevsky St., P.O. Box 30, Kazan 420111, Russia (N.V.Z.)
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Prömer J, Barresi C, Herbst R. From phosphorylation to phenotype - Recent key findings on kinase regulation, downstream signaling and disease surrounding the receptor tyrosine kinase MuSK. Cell Signal 2023; 104:110584. [PMID: 36608736 DOI: 10.1016/j.cellsig.2022.110584] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/16/2022] [Accepted: 12/31/2022] [Indexed: 01/04/2023]
Abstract
Muscle-specific kinase (MuSK) is the key regulator of neuromuscular junction development. MuSK acts via several distinct pathways and is responsible for pre- and postsynaptic differentiation. MuSK is unique among receptor tyrosine kinases as activation and signaling are particularly tightly regulated. Initiation of kinase activity requires Agrin, a heparan sulphate proteoglycan derived from motor neurons, the low-density lipoprotein receptor-related protein-4 (Lrp4) and the intracellular adaptor protein Dok-7. There is a great knowledge gap between MuSK activation and downstream signaling. Recent studies using omics techniques have addressed this knowledge gap, thereby greatly contributing to a better understanding of MuSK signaling. Impaired MuSK signaling causes severe muscle weakness as described in congenital myasthenic syndromes or myasthenia gravis but the underlying pathophysiology is often unclear. This review focuses on recent advances in deciphering MuSK activation and downstream signaling. We further highlight latest break-throughs in understanding and treatment of MuSK-related disorders and discuss the role of MuSK in non-muscle tissue.
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Affiliation(s)
- Jakob Prömer
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Cinzia Barresi
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Ruth Herbst
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
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43
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Hao Y, Liu H, Zeng XT, Wang Y, Zeng WX, Qian KY, Li L, Chi MX, Gao S, Hu Z, Tong XJ. UNC-43/CaMKII-triggered anterograde signals recruit GABA ARs to mediate inhibitory synaptic transmission and plasticity at C. elegans NMJs. Nat Commun 2023; 14:1436. [PMID: 36918518 PMCID: PMC10015018 DOI: 10.1038/s41467-023-37137-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 02/28/2023] [Indexed: 03/16/2023] Open
Abstract
Disturbed inhibitory synaptic transmission has functional impacts on neurodevelopmental and psychiatric disorders. An essential mechanism for modulating inhibitory synaptic transmission is alteration of the postsynaptic abundance of GABAARs, which are stabilized by postsynaptic scaffold proteins and recruited by presynaptic signals. However, how GABAergic neurons trigger signals to transsynaptically recruit GABAARs remains elusive. Here, we show that UNC-43/CaMKII functions at GABAergic neurons to recruit GABAARs and modulate inhibitory synaptic transmission at C. elegans neuromuscular junctions. We demonstrate that UNC-43 promotes presynaptic MADD-4B/Punctin secretion and NRX-1α/Neurexin surface delivery. Together, MADD-4B and NRX-1α recruit postsynaptic NLG-1/Neuroligin and stabilize GABAARs. Further, the excitation of GABAergic neurons potentiates the recruitment of NLG-1-stabilized-GABAARs, which depends on UNC-43, MADD-4B, and NRX-1. These data all support that UNC-43 triggers MADD-4B and NRX-1α, which act as anterograde signals to recruit postsynaptic GABAARs. Thus, our findings elucidate a mechanism for pre- and postsynaptic communication and inhibitory synaptic transmission and plasticity.
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Affiliation(s)
- Yue Hao
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Haowen Liu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Xian-Ting Zeng
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Ya Wang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Wan-Xin Zeng
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Kang-Ying Qian
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Lei Li
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Ming-Xuan Chi
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Shangbang Gao
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhitao Hu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Xia-Jing Tong
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
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Pollock N, Macpherson PC, Staunton CA, Hemmings K, Davis CS, Owen ED, Vasilaki A, Van Remmen H, Richardson A, McArdle A, Brooks SV, Jackson MJ. Deletion of Sod1 in Motor Neurons Exacerbates Age-Related Changes in Axons and Neuromuscular Junctions in Mice. eNeuro 2023; 10:ENEURO.0086-22.2023. [PMID: 36810149 PMCID: PMC10026931 DOI: 10.1523/eneuro.0086-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 02/03/2023] [Accepted: 02/05/2023] [Indexed: 02/23/2023] Open
Abstract
Whole-body knock-out of Cu,Zn superoxide dismutase (Sod1KO) results in accelerated, age-related loss of muscle mass and function associated with neuromuscular junction (NMJ) breakdown similar to sarcopenia. In order to determine whether altered redox in motor neurons underlies this phenotype, an inducible neuron-specific deletion of Sod1 (i-mnSod1KO) was compared with wild-type (WT) mice of different ages (adult, mid-age, and old) and whole-body Sod1KO mice. Nerve oxidative damage, motor neuron numbers and structural changes to neurons and NMJ were examined. Tamoxifen-induced deletion of neuronal Sod1 from two months of age. No specific effect of a lack of neuronal Sod1 was seen on markers of nerve oxidation (electron paramagnetic resonance of an in vivo spin probe, protein carbonyl, or protein 3-nitrotyrosine contents). i-mnSod1KO mice showed increased denervated NMJ, reduced numbers of large axons and increased number of small axons compared with old WT mice. A large proportion of the innervated NMJs in old i-mnSod1KO mice displayed a simpler structure than that seen in adult or old WT mice. Thus, previous work showed that neuronal deletion of Sod1 induced exaggerated loss of muscle in old mice, and we report that this deletion leads to a specific nerve phenotype including reduced axonal area, increased proportion of denervated NMJ, and reduced acetyl choline receptor complexity. Other changes in nerve and NMJ structure seen in the old i-mnSod1KO mice reflect aging of the mice.
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Affiliation(s)
- N Pollock
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
| | - P C Macpherson
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, 48109 MI
| | - C A Staunton
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
| | - K Hemmings
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
| | - C S Davis
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, 48109 MI
| | - E D Owen
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
| | - A Vasilaki
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
| | - H Van Remmen
- Oklahoma Medical Research Foundation (OMRF), Oklahoma City, 73104, OK
| | - A Richardson
- University of Oklahoma Health Science Center (OUHSC), Oklahoma City, 73104, OK
| | - A McArdle
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
| | - S V Brooks
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, 48109 MI
| | - M J Jackson
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
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45
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Mrestani A, Lichter K, Sirén AL, Heckmann M, Paul MM, Pauli M. Single-Molecule Localization Microscopy of Presynaptic Active Zones in Drosophila melanogaster after Rapid Cryofixation. Int J Mol Sci 2023; 24:ijms24032128. [PMID: 36768451 PMCID: PMC9917252 DOI: 10.3390/ijms24032128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/25/2023] Open
Abstract
Single-molecule localization microscopy (SMLM) greatly advances structural studies of diverse biological tissues. For example, presynaptic active zone (AZ) nanotopology is resolved in increasing detail. Immunofluorescence imaging of AZ proteins usually relies on epitope preservation using aldehyde-based immunocompetent fixation. Cryofixation techniques, such as high-pressure freezing (HPF) and freeze substitution (FS), are widely used for ultrastructural studies of presynaptic architecture in electron microscopy (EM). HPF/FS demonstrated nearer-to-native preservation of AZ ultrastructure, e.g., by facilitating single filamentous structures. Here, we present a protocol combining the advantages of HPF/FS and direct stochastic optical reconstruction microscopy (dSTORM) to quantify nanotopology of the AZ scaffold protein Bruchpilot (Brp) at neuromuscular junctions (NMJs) of Drosophila melanogaster. Using this standardized model, we tested for preservation of Brp clusters in different FS protocols compared to classical aldehyde fixation. In HPF/FS samples, presynaptic boutons were structurally well preserved with ~22% smaller Brp clusters that allowed quantification of subcluster topology. In summary, we established a standardized near-to-native preparation and immunohistochemistry protocol for SMLM analyses of AZ protein clusters in a defined model synapse. Our protocol could be adapted to study protein arrangements at single-molecule resolution in other intact tissue preparations.
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Affiliation(s)
- Achmed Mrestani
- Department of Neurophysiology, Institute for Physiology, University of Würzburg, 97070 Würzburg, Germany
- Division of General Biochemistry, Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
- Department of Neurology, Leipzig University Medical Center, 04103 Leipzig, Germany
| | - Katharina Lichter
- Department of Neurophysiology, Institute for Physiology, University of Würzburg, 97070 Würzburg, Germany
- Department of Neurosurgery, University Hospital of Würzburg, 97080 Würzburg, Germany
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Anna-Leena Sirén
- Department of Neurophysiology, Institute for Physiology, University of Würzburg, 97070 Würzburg, Germany
- Department of Neurosurgery, University Hospital of Würzburg, 97080 Würzburg, Germany
- Correspondence:
| | - Manfred Heckmann
- Department of Neurophysiology, Institute for Physiology, University of Würzburg, 97070 Würzburg, Germany
| | - Mila M. Paul
- Department of Neurophysiology, Institute for Physiology, University of Würzburg, 97070 Würzburg, Germany
- Department of Orthopaedic Trauma, Hand, Plastic and Reconstructive Surgery, University Hospital of Würzburg, 97080 Wurzburg, Germany
| | - Martin Pauli
- Department of Neurophysiology, Institute for Physiology, University of Würzburg, 97070 Würzburg, Germany
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Pugliese A, Holland SH, Rodolico C, Lochmüller H, Spendiff S. Presynaptic Congenital Myasthenic Syndromes: Understanding Clinical Phenotypes through In vivo Models. J Neuromuscul Dis 2023; 10:731-759. [PMID: 37212067 PMCID: PMC10578258 DOI: 10.3233/jnd-221646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2023] [Indexed: 05/23/2023]
Abstract
Presynaptic congenital myasthenic syndromes (CMS) are a group of genetic disorders affecting the presynaptic side of the neuromuscular junctions (NMJ). They can result from a dysfunction in acetylcholine (ACh) synthesis or recycling, in its packaging into synaptic vesicles, or its subsequent release into the synaptic cleft. Other proteins involved in presynaptic endplate development and maintenance can also be impaired.Presynaptic CMS usually presents during the prenatal or neonatal period, with a severe phenotype including congenital arthrogryposis, developmental delay, and apnoeic crisis. However, milder phenotypes with proximal muscle weakness and good response to treatment have been described. Finally, many presynaptic genes are expressed in the brain, justifying the presence of additional central nervous system symptoms.Several animal models have been developed to study CMS, providing the opportunity to identify disease mechanisms and test treatment options. In this review, we describe presynaptic CMS phenotypes with a focus on in vivo models, to better understand CMS pathophysiology and define new causative genes.
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Affiliation(s)
- Alessia Pugliese
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Stephen H. Holland
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Carmelo Rodolico
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Hanns Lochmüller
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Department of Medicine, Division of Neurology, The Ottawa Hospital, Ottawa, ON, Canada
- Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
- Department of Neuropediatrics and Muscle Disorders, Medical Center – University of Freiburg, Faculty of Medicine, Freiburg, Germany
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia, Spain
| | - Sally Spendiff
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
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Luderman LN, Michaels MT, Levic DS, Knapik EW. Zebrafish Erc1b mediates motor innervation and organization of craniofacial muscles in control of jaw movement. Dev Dyn 2023; 252:104-123. [PMID: 35708710 DOI: 10.1002/dvdy.511] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 05/31/2022] [Accepted: 06/03/2022] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Movement of the lower jaw, a common behavior observed among vertebrates, is required for eating and processing food. This movement is controlled by signals sent from the trigeminal motor nerve through neuromuscular junctions (NMJs) to the masticatory muscles. Dysfunctional jaw movements contribute to craniomandibular disorders, yet the pathophysiology of these disorders is not well understood, as limited studies have been conducted on the molecular mechanisms of jaw movement. RESULTS Using erc1b/kimm533 genetic loss of function mutant, we evaluated lower jaw muscle organization and innervation by the cranial motor nerves in developing zebrafish. Using time-lapse confocal imaging of the erc1b mutant in a transgenic fluorescent reporter line, we found delayed trigeminal nerve growth and disrupted nerve branching architecture during muscle innervation. By automated 3D image analysis of NMJ distribution, we identified an increased number of small, disorganized NMJ clusters in erc1b mutant larvae compared to WT siblings. Using genetic replacement experiments, we determined the Rab GTPase binding domain of Erc1b is required for cranial motor nerve branching, but not NMJ organization or muscle attachment. CONCLUSIONS We identified Erc1b/ERC1 as a novel component of a genetic pathway contributing to muscle organization, trigeminal nerve outgrowth, and NMJ spatial distribution during development that is required for jaw movement.
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Affiliation(s)
- Lauryn N Luderman
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
| | - Mackenzie T Michaels
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Daniel S Levic
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
- Neuroscience Graduate Program, Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
| | - Ela W Knapik
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
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Caron L, Testa S, Magdinier F. Induced Pluripotent Stem Cells for Modeling Physiological and Pathological Striated Muscle Complexity. J Neuromuscul Dis 2023; 10:761-776. [PMID: 37522215 PMCID: PMC10578229 DOI: 10.3233/jnd-230076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2023] [Indexed: 08/01/2023]
Abstract
Neuromuscular disorders (NMDs) are a large group of diseases associated with either alterations of skeletal muscle fibers, motor neurons or neuromuscular junctions. Most of these diseases is characterized with muscle weakness or wasting and greatly alter the life of patients. Animal models do not always recapitulate the phenotype of patients. The development of innovative and representative human preclinical models is thus strongly needed for modeling the wide diversity of NMDs, characterization of disease-associated variants, investigation of novel genes function, or the development of therapies. Over the last decade, the use of patient's derived induced pluripotent stem cells (hiPSC) has resulted in tremendous progress in biomedical research, including for NMDs. Skeletal muscle is a complex tissue with multinucleated muscle fibers supported by a dense extracellular matrix and multiple cell types including motor neurons required for the contractile activity. Major challenges need now to be tackled by the scientific community to increase maturation of muscle fibers in vitro, in particular for modeling adult-onset diseases affecting this tissue (neuromuscular disorders, cachexia, sarcopenia) and the evaluation of therapeutic strategies. In the near future, rapidly evolving bioengineering approaches applied to hiPSC will undoubtedly become highly instrumental for investigating muscle pathophysiology and the development of therapeutic strategies.
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Affiliation(s)
- Leslie Caron
- Aix-Marseille Univ-INSERM, MMG, Marseille, France
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Dyson A, Ryan M, Garg S, Evans DG, Baines RA. Loss of NF1 in Drosophila Larvae Causes Tactile Hypersensitivity and Impaired Synaptic Transmission at the Neuromuscular Junction. J Neurosci 2022; 42:9450-9472. [PMID: 36344265 PMCID: PMC9794380 DOI: 10.1523/jneurosci.0562-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 11/09/2022] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental condition in which the mechanisms underlying its core symptomatology are largely unknown. Studying animal models of monogenic syndromes associated with ASD, such as neurofibromatosis type 1 (NF1), can offer insights into its etiology. Here, we show that loss of function of the Drosophila NF1 ortholog results in tactile hypersensitivity following brief mechanical stimulation in the larva (mixed sexes), paralleling the sensory abnormalities observed in individuals with ASD. Mutant larvae also exhibit synaptic transmission deficits at the glutamatergic neuromuscular junction (NMJ), with increased spontaneous but reduced evoked release. While the latter is homeostatically compensated for by a postsynaptic increase in input resistance, the former is consistent with neuronal hyperexcitability. Indeed, diminished expression of NF1 specifically within central cholinergic neurons induces both excessive neuronal firing and tactile hypersensitivity, suggesting the two may be linked. Furthermore, both impaired synaptic transmission and behavioral deficits are fully rescued via knock-down of Ras proteins. These findings validate NF1 -/- Drosophila as a tractable model of ASD with the potential to elucidate important pathophysiological mechanisms.SIGNIFICANCE STATEMENT Autism spectrum disorder (ASD) affects 1-2% of the overall population and can considerably impact an individual's quality of life. However, there are currently no treatments available for its core symptoms, largely because of a poor understanding of the underlying mechanisms involved. Examining how loss of function of the ASD-associated NF1 gene affects behavior and physiology in Drosophila may shed light on this. In this study, we identify a novel, ASD-relevant behavioral phenotype in NF1 -/- larvae, namely an enhanced response to mechanical stimulation, which is associated with Ras-dependent synaptic transmission deficits indicative of neuronal hyperexcitability. Such insights support the use of Drosophila neurofibromatosis type 1 (NF1) models in ASD research and may provide outputs for genetic or pharmacological screens in future studies.
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Affiliation(s)
- Alex Dyson
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Megan Ryan
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Shruti Garg
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
- Child & Adolescent Mental Health Services, Royal Manchester Children's Hospital, Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Sciences Centre, Manchester, M13 9WL, United Kingdom
| | - D Gareth Evans
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Richard A Baines
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
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Wu SH, Lu IC, Yang SM, Hsieh CF, Chai CY, Tai MH, Huang SH. Spinal Irisin Gene Delivery Attenuates Burn Injury-Induced Muscle Atrophy by Promoting Axonal Myelination and Innervation of Neuromuscular Junctions. Int J Mol Sci 2022; 23:ijms232415899. [PMID: 36555538 PMCID: PMC9784798 DOI: 10.3390/ijms232415899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/10/2022] [Accepted: 12/12/2022] [Indexed: 12/15/2022] Open
Abstract
Muscle loss and weakness after a burn injury are typically the consequences of neuronal dysregulation and metabolic change. Hypermetabolism has been noted to cause muscle atrophy. However, the mechanism underlying the development of burn-induced motor neuropathy and its contribution to muscle atrophy warrant elucidation. Current therapeutic interventions for burn-induced motor neuropathy demonstrate moderate efficacy and have side effects, which limit their usage. We previously used a third-degree burn injury rodent model and found that irisin-an exercise-induced myokine-exerts a protective effect against burn injury-induced sensory and motor neuropathy by attenuating neuronal damage in the spinal cord. In the current study, spinal irisin gene delivery was noted to attenuate burn injury-induced sciatic nerve demyelination and reduction of neuromuscular junction innervation. Spinal overexpression of irisin leads to myelination rehabilitation and muscular innervation through the modulation of brain-derived neurotrophic factor and glial-cell-line-derived neurotrophic factor expression along the sciatic nerve to the muscle tissues and thereby modulates the Akt/mTOR pathway and metabolic derangement and prevents muscle atrophy.
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Affiliation(s)
- Sheng-Hua Wu
- Department of Anesthesiology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung 801, Taiwan
- Department of Anesthesiology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Department of Anesthesiology, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
| | - I-Cheng Lu
- Department of Anesthesiology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Department of Anesthesiology, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
- Department of Anesthesiology, Kaohsiung Municipal Siaogang Hospital, Kaohsiung 812, Taiwan
| | - Shih-Ming Yang
- Institute of Biomedical Sciences, National Sun Yat-Sun University, Kaohsiung 804, Taiwan
| | - Chia-Fang Hsieh
- Department of Anesthesiology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung 801, Taiwan
| | - Chee-Yin Chai
- Institute of Biomedical Sciences, National Sun Yat-Sun University, Kaohsiung 804, Taiwan
- Department of Pathology, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
| | - Ming-Hong Tai
- Institute of Biomedical Sciences, National Sun Yat-Sun University, Kaohsiung 804, Taiwan
- Correspondence: (M.-H.T.); (S.-H.H.)
| | - Shu-Hung Huang
- Department of Surgery, Division of Plastic Surgery, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
- Department of Surgery, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Regeneration Medicine and Cell Therapy Research Center, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Department of Surgery, Division of Plastic Surgery, Kaohsiung Municipal Siaogang Hospital, Kaohsiung 812, Taiwan
- Correspondence: (M.-H.T.); (S.-H.H.)
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