Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1033983 | ENA |
REPOSITORIES: ENA
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Project description:Understanding neuromuscular junction (NMJ) repair mechanisms is essential for addressing degenerative neuromuscular conditions. Here, we focus on the role of muscle-resident Schwann cells in NMJ reinnervation. Using an accepted model of progressive NMJ degeneration, Sod1-/- mice, we identified a clear NMJ ‘regenerative window’ that allowed us to define cellular and molecular regulators of synapse remodeling and muscle fiber reinnervation. High-resolution imaging and single-cell RNA sequencing provide a detailed analysis of Schwann cell number, morphology, and transcriptome revealing multiple subtypes, including a previously unrecognized terminal Schwann cell (tSC) population expressing a synapse promoting signature. We also discovered a novel SPP1-driven cellular interaction between myelin Schwann cells and tSCs and show that it promotes tSC proliferation and reinnervation following nerve injury in wild type mice. Our findings offer important insights into molecular regulators critical in NMJ reinnervation that are mediated through tSCs to maintain NMJ function.
2024-11-02 | GSE246865 | GEO
Project description:Neuromuscular networks assemble during early human embryonic development and are essential for the control of body movement. Previous neuromuscular junction modeling efforts using human pluripotent stem cells (hPSCs) generated either spinal cord neurons or skeletal muscles in monolayer culture. Here, we use hPSC-derived axial stem cells, the building blocks of the posterior body, to simultaneously generate spinal cord neurons and skeletal muscle cells that self-organize to generate human neuromuscular organoids (NMOs) that can be maintained in 3D for several months. Single-cell RNA-sequencing of individual organoids revealed reproducibility across experiments and enabled the tracking of the neural and mesodermal differentiation trajectories as organoids developed and matured. NMOs contain functional neuromuscular junctions supported by terminal Schwann cells. They contract and develop central pattern generator-like neuronal circuits. Finally, we successfully use NMOs to recapitulate key aspects of myasthenia gravis pathology, thus highlighting the significant potential of NMOs for modeling neuromuscular diseases in the future.
2020-01-20 | GSE128357 | GEO
Project description:Molecular mechanisms underlying sarcopenia, the age-related loss of skeletal muscle mass and function, remain unclear. To identify molecular changes that correlated best with sarcopenia and might contribute to its pathogenesis, we determined global gene expression profiles in muscles of rats aged 6, 12, 18, 21, 24, and 27 months. These rats exhibit sarcopenia beginning at 21 months. Correlation of the gene expression versus muscle mass or age changes, and functional annotation analysis identified gene signatures of sarcopenia distinct from gene signatures of aging. Specifically, mitochondrial energy metabolism (e.g., tricarboxylic acid cycle and oxidative phosphorylation) pathway genes were the most downregulated and most significantly correlated with sarcopenia. Also, perturbed were genes/pathways associated with neuromuscular junction patency (providing molecular evidence of sarcopenia-related functional denervation and neuromuscular junction remodeling), protein degradation, and inflammation. Proteomic analysis of samples at 6, 18, and 27 months confirmed the depletion of mitochondrial energy metabolism proteins and neuromuscular junction proteins. Together, these findings suggest that therapeutic approaches that simultaneously stimulate mitochondrogenesis and reduce muscle proteolysis and inflammation have potential for treating sarcopenia.
2018-08-21 | GSE118825 | GEO
Project description:The neuromuscular junction (NMJ) is a specialized tripartite synapse composed of the motor axon terminal, covered by perisynaptic Schwann cells (PSCs), and the muscle fibre, separated by a basal lamina. It is exposed to different kind of injures such as mechanical traumas, pathogens including neurotoxins, and neuromuscular diseases such as amyotrophic lateral sclerosis and immune-mediated disorders, and has retained throughout vertebrate evolution an intrinsic ability for repair and regeneration, at variance from central synapses1. Following peripheral nerve injury, an intense but poorly defined crosstalk takes place at the NMJ among its components, functional to nerve terminal regeneration. To identify crucial factors released by PSCs and the muscle to induce nerve regrowth, we performed a transcriptome analysis of the NMJ at different time points after injection of -latrotoxin, a presynaptic neurotoxin isolated from the venom of the black widow spider. This toxin is a simple and controlled method to induce an acute, localized and reversible nerve terminal degeneration not blurred by inflammation, and can help to identify molecules involved in the intra- and inter-cellular signalling governing NMJ regeneration.
2017-05-30 | E-MTAB-5730 | biostudies-arrayexpress
Project description:We utilized genetic methods to examine how Schwann cells prevent degeneration of motor neurons (MNs) in the spinal cord. Blocking peripheral, neuromuscular activity completely rescued MNs and neuromuscular junctions (NMJs) in erbB3 mutant mice lacking Schwann cells, which normally exhibit profound neurodegeneration. We searched for the molecular basis of this effect by examining the transcriptomes (all of the expressed genes) in the muscle of control mice with Schwann cells and erbB3 mutant mice without them. We found evidence that a negative signal expressed by muscle was regulated by neural activity and normally blocked by factors produced in Schwann cells. When we eliminated this activity-induced negative signal (thrombin) from muscle, MNs and NMJs were protected in erbB3 mutants, similar to the effects of eliminating activity. Together, these results suggest that Schwann cells prevent neurodegeneration by inhibiting the effect of activity-induced, muscle-derived negative factors, rather than by providing trophic positive factors.
2019-03-14 | GSE125490 | GEO
Project description:Analysis of denervation induced regulation of muscle mass at gene expression level. The hypothesis tested in the present study was that the presence of MuRF1 contributes to the extent of gene expression changes observed in specific sets of genes during a challenge leading to muscle atrophy. Results provide important information on the response of triceps surae muscle to sciatic nerve resection (denervation), such as specific structural, metabolic, and neuromuscular junction associated genes, that may be influenced by MuRF1 during atrophy. Total RNA obtained from isolated triceps surae muscle subjected to 3 or 14 days post-denervation compared to nonsurgically treated littermate control muscles.
2013-02-12 | E-GEOD-44205 | biostudies-arrayexpress
Project description:During aging and neuromuscular diseases, there is a progressive loss of skeletal muscle volume and function, which is often associated with denervation and a loss of muscle stem cells (MuSCs). A relationship between MuSCs and innervation has not been established however. Herein, we administered neuromuscular trauma to a MuSC lineage tracing model and observed a subset of MuSCs specifically engraft in a position proximal to the neuromuscular junction (NMJ). In aging and in a model of neuromuscular degeneration (Sod1-/-), this localized engraftment behavior was reduced. Genetic rescue of motor neurons in Sod1-/- mice reestablished integrity of the NMJ and partially restored MuSC ability to engraft into NMJ proximal positions. Using single cell RNA-sequencing of MuSCs, we demonstrate that a subset of MuSCs are molecularly distinguishable from MuSCs responding to myofiber injury. These data reveal unique features of MuSCs that respond to synaptic perturbations caused by aging and other stressors.
2021-05-06 | GSE165978 | GEO
Project description:Perisynaptic Schwann cells (PSCs) are specialized, non-myelinating, synaptic glia of the neuromuscular junction (NMJ), that participate in synapse development, function, maintenance, and repair. The study of PSCs has relied on an anatomy-based approach, as the identities of cell-specific PSC molecular markers have remained elusive. This limited approach has precluded our ability to isolate and genetically manipulate PSCs in a cell specific manner. We have identified neuron-glia antigen 2 (NG2) as a unique molecular marker of S100β+ PSCs in skeletal muscle. NG2 is expressed in Schwann cells already associated with the NMJ, indicating that it is a marker of differentiated PSCs. Using a newly generated transgenic mouse in which PSCs are specifically labeled, we show that PSCs have a unique molecular signature that includes genes known to play critical roles in PSCs and synapses. These findings will serve as a springboard for revealing drivers of PSC differentiation and function.
2020-06-19 | GSE152774 | GEO
Project description:Analysis of denervation induced regulation of muscle mass at gene expression level. The hypothesis tested in the present study was that the presence of MuRF1 contributes to the extent of gene expression changes observed in specific sets of genes during a challenge leading to muscle atrophy. Results provide important information on the response of triceps surae muscle to sciatic nerve resection (denervation), such as specific structural, metabolic, and neuromuscular junction associated genes, that may be influenced by MuRF1 during atrophy.
2013-02-12 | GSE44205 | GEO