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Frontiers in Cellular Neuroscience 2023Schwann cells (SCs) have a critical role in the peripheral nervous system. These cells are able to support axons during homeostasis and after injury. However, mutations... (Review)
Review
Schwann cells (SCs) have a critical role in the peripheral nervous system. These cells are able to support axons during homeostasis and after injury. However, mutations in genes associated with the SCs repair program or myelination result in dysfunctional SCs. Several neuropathies such as Charcot-Marie-Tooth (CMT) disease, diabetic neuropathy and Guillain-Barré syndrome show abnormal SC functions and an impaired regeneration process. Thus, understanding SCs-axon interaction and the nerve environment in the context of homeostasis as well as post-injury and disease onset is necessary. Several neurotrophic factors, cytokines, and regulators of signaling pathways associated with proliferation, survival and regeneration are involved in this process. Preclinical studies have focused on the discovery of therapeutic targets for peripheral neuropathies and injuries. To study the effect of new therapeutic targets, modeling neuropathies and peripheral nerve injuries (PNIs) and are useful tools. Furthermore, several protocols have been designed using SCs and neuron cell lines to evaluate these targets in the regeneration process. SCs lines have been used to generate effective myelinating SCs without success. Alternative options have been investigated using direct conversion from somatic cells to SCs or SCs derived from pluripotent stem cells to generate functional SCs. This review will go over the advantages of these systems and the problems associated with them. In addition, there have been challenges in establishing adequate and reproducible protocols to recapitulate repair SC-neuron interactions observed . So, we also discuss the mechanisms of repair SCs-axon interactions in the context of peripheral neuropathies and nerve injury (PNI) and . Finally, we summarize current preclinical studies evaluating transgenes, drug, and novel compounds with translational potential into clinical studies.
PubMed: 37900588
DOI: 10.3389/fncel.2023.1248922 -
Nature Communications Oct 2023Previous work has shown that motor skill learning stimulates and requires generation of myelinating oligodendrocytes (OLs) from their precursor cells (OLPs) in the...
Previous work has shown that motor skill learning stimulates and requires generation of myelinating oligodendrocytes (OLs) from their precursor cells (OLPs) in the brains of adult mice. In the present study we ask whether OL production is also required for non-motor learning and cognition, using T-maze and radial-arm-maze tasks that tax spatial working memory. We find that maze training stimulates OLP proliferation and OL production in the medial prefrontal cortex (mPFC), anterior corpus callosum (genu), dorsal thalamus and hippocampal formation of adult male mice; myelin sheath formation is also stimulated in the genu. Genetic blockade of OL differentiation and neo-myelination in Myrf conditional-knockout mice strongly impairs training-induced improvements in maze performance. We find a strong positive correlation between the performance of individual wild type mice and the scale of OLP proliferation and OL generation during training, but not with the number or intensity of c-Fos neurons in their mPFC, underscoring the important role played by OL lineage cells in cognitive processing.
Topics: Humans; Mice; Animals; Male; Memory, Short-Term; Cognitive Training; Oligodendroglia; Mice, Knockout; Cognition; Myelin Sheath
PubMed: 37838794
DOI: 10.1038/s41467-023-42293-4 -
The Journal of Biological Chemistry Dec 2023Peripheral glial Schwann cells switch to a repair state after nerve injury, proliferate to supply lost cell population, migrate to form regeneration tracks, and...
Peripheral glial Schwann cells switch to a repair state after nerve injury, proliferate to supply lost cell population, migrate to form regeneration tracks, and contribute to the generation of a permissive microenvironment for nerve regeneration. Exploring essential regulators of the repair responses of Schwann cells may benefit the clinical treatment for peripheral nerve injury. In the present study, we find that FOSL1, a AP-1 member that encodes transcription factor FOS Like 1, is highly expressed at the injured sites following peripheral nerve crush. Interfering FOSL1 decreases the proliferation rate and migration ability of Schwann cells, leading to impaired nerve regeneration. Mechanism investigations demonstrate that FOSL1 regulates Schwann cell proliferation and migration by directly binding to the promoter of EPH Receptor B2 (EPHB2) and promoting EPHB2 transcription. Collectively, our findings reveal the essential roles of FOSL1 in regulating the activation of Schwann cells and indicate that FOSL1 can be targeted as a novel therapeutic approach to orchestrate the regeneration and functional recovery of injured peripheral nerves.
Topics: Nerve Regeneration; Peripheral Nerve Injuries; Peripheral Nerves; Schwann Cells; Animals; Rats; Rats, Sprague-Dawley
PubMed: 37949219
DOI: 10.1016/j.jbc.2023.105444 -
Cell Reports Dec 2023Multiple sclerosis (MS) is an inflammatory disease characterized by myelin loss. While therapies exist to slow MS progression, no treatment currently exists for...
Multiple sclerosis (MS) is an inflammatory disease characterized by myelin loss. While therapies exist to slow MS progression, no treatment currently exists for remyelination. Remyelination, linked to reduced disability in MS, relies on microglia and monocyte-derived macrophages (MDMs). This study aims to understand the role of microglia during remyelination by lineage tracing and depleting them. Microglial lineage tracing reveals that both microglia and MDMs initially accumulate, but microglia later dominate the lesion. Microglia and MDMs engulf equal amounts of inhibitory myelin debris, but after microglial depletion, MDMs compensate by engulfing more myelin debris. Microglial depletion does, however, reduce the recruitment and proliferation of oligodendrocyte progenitor cells (OPCs) and impairs their subsequent differentiation and remyelination. These findings underscore the essential role of microglia during remyelination and offer insights for enhancing this process by understanding microglial regulation of remyelination.
Topics: Humans; Myelin Sheath; Microglia; Remyelination; Demyelinating Diseases; Macrophages; Multiple Sclerosis
PubMed: 38100356
DOI: 10.1016/j.celrep.2023.113574 -
Neuro-oncology Dec 2023Schwannomas are common peripheral nerve sheath tumors that can cause severe morbidity given their stereotypic intracranial and paraspinal locations. Similar to many...
BACKGROUND
Schwannomas are common peripheral nerve sheath tumors that can cause severe morbidity given their stereotypic intracranial and paraspinal locations. Similar to many solid tumors, schwannomas and other nerve sheath tumors are primarily thought to arise due to aberrant hyperactivation of the RAS growth factor signaling pathway. Here, we sought to further define the molecular pathogenesis of schwannomas.
METHODS
We performed comprehensive genomic profiling on a cohort of 96 human schwannomas, as well as DNA methylation profiling on a subset. Functional studies including RNA sequencing, chromatin immunoprecipitation-DNA sequencing, electrophoretic mobility shift assay, and luciferase reporter assays were performed in a fetal glial cell model following transduction with wildtype and tumor-derived mutant isoforms of SOX10.
RESULTS
We identified that nearly one-third of sporadic schwannomas lack alterations in known nerve sheath tumor genes and instead harbor novel recurrent in-frame insertion/deletion mutations in SOX10, which encodes a transcription factor responsible for controlling Schwann cell differentiation and myelination. SOX10 indel mutations were highly enriched in schwannomas arising from nonvestibular cranial nerves (eg facial, trigeminal, vagus) and were absent from vestibular nerve schwannomas driven by NF2 mutation. Functional studies revealed these SOX10 indel mutations have retained DNA binding capacity but impaired transactivation of glial differentiation and myelination gene programs.
CONCLUSIONS
We thus speculate that SOX10 indel mutations drive a unique subtype of schwannomas by impeding proper differentiation of immature Schwann cells.
Topics: Humans; INDEL Mutation; Transcriptional Activation; Neurilemmoma; Neuroma, Acoustic; Mutation; Nerve Sheath Neoplasms; SOXE Transcription Factors
PubMed: 37436963
DOI: 10.1093/neuonc/noad121 -
International Journal of Molecular... Jul 2023Recovery from a traumatic spinal cord injury (TSCI) is challenging due to the limited regenerative capacity of the central nervous system to restore cells, myelin, and... (Review)
Review
Recovery from a traumatic spinal cord injury (TSCI) is challenging due to the limited regenerative capacity of the central nervous system to restore cells, myelin, and neural connections. Cell therapy, particularly with mesenchymal stem cells (MSCs), holds significant promise for TSCI treatment. This systematic review aims to analyze the efficacy, safety, and therapeutic potential of MSC-based cell therapies in TSCI. A comprehensive search of PUBMED and COCHRANE databases until February 2023 was conducted, combining terms such as "spinal cord injury," "stem cells," "stem cell therapy," "mesenchymal stem cells," and "traumatic spinal cord injury". Among the 53 studies initially identified, 22 (21 clinical trials and 1 case series) were included. Findings from these studies consistently demonstrate improvements in AIS (ASIA Impairment Scale) grades, sensory scores, and, to a lesser extent, motor scores. Meta-analyses further support these positive outcomes. MSC-based therapies have shown short- and medium-term safety, as indicated by the absence of significant adverse events within the studied timeframe. However, caution is required when drawing generalized recommendations due to the limited scientific evidence available. Further research is needed to elucidate the long-term safety and clinical implications of these advancements. Although significant progress has been made, particularly with MSC-based therapies, additional studies exploring other potential future therapies such as gene therapies, neurostimulation techniques, and tissue engineering approaches are essential for a comprehensive understanding of the evolving TSCI treatment landscape.
Topics: Humans; Mesenchymal Stem Cell Transplantation; Spinal Cord Injuries; Cell- and Tissue-Based Therapy; Myelin Sheath; Mesenchymal Stem Cells; Spinal Cord
PubMed: 37511478
DOI: 10.3390/ijms241411719 -
Communications Biology Jul 2023Brown adipose tissue (BAT) is responsible for regulating body temperature through adaptive thermogenesis. The ability of thermogenic adipocytes to dissipate chemical...
Brown adipose tissue (BAT) is responsible for regulating body temperature through adaptive thermogenesis. The ability of thermogenic adipocytes to dissipate chemical energy as heat counteracts weight gain and has gained considerable attention as a strategy against obesity. BAT undergoes major remodeling in a cold environment. This remodeling results from changes in the number and function of brown adipocytes, expanding the network of blood vessels and sympathetic nerves, and changes in the composition and function of immune cells. Such synergistic adaptation requires extensive crosstalk between individual cells in the tissue to coordinate their responses. To understand the mechanisms of intercellular communication in BAT, we apply the CellChat algorithm to single-cell transcriptomic data of mouse BAT. We construct an integrative network of the ligand-receptor interactome in BAT and identify the major signaling inputs and outputs of each cell type. By comparing the ligand-receptor interactions in BAT of mice housed at different environmental temperatures, we show that cold exposure enhances the intercellular interactions among the major cell types in BAT, including adipocytes, adipocyte progenitors, lymphatic and vascular endothelial cells, myelinated and non-myelinated Schwann cells, and immune cells. These interactions are predicted to regulate the remodeling of the extracellular matrix, the inflammatory response, angiogenesis, and neurite growth. Together, our integrative analysis of intercellular communications in BAT and their dynamic regulation in response to housing temperatures provides a new understanding of the mechanisms underlying BAT thermogenesis. The resources presented in this study offer a valuable platform for future investigations of BAT development and thermogenesis.
Topics: Animals; Mice; Endothelial Cells; Ligands; Obesity; Cell Communication; Adipocytes, Brown
PubMed: 37479789
DOI: 10.1038/s42003-023-05140-2 -
Neurobiology of Disease Aug 2023Oligodendrocytes (OLs), the myelin-forming cells of the central nervous system, are integral to axonal integrity and function. Hypoxia-ischemia episodes can cause severe... (Review)
Review
Oligodendrocytes (OLs), the myelin-forming cells of the central nervous system, are integral to axonal integrity and function. Hypoxia-ischemia episodes can cause severe damage to these vulnerable cells through excitotoxicity, oxidative stress, inflammation, and mitochondrial dysfunction, leading to axonal dystrophy, neuronal dysfunction, and neurological impairments. OLs damage can result in demyelination and myelination disorders, severely impacting axonal function, structure, metabolism, and survival. Adult-onset stroke, periventricular leukomalacia, and post-stroke cognitive impairment primarily target OLs, making them a critical therapeutic target. Therapeutic strategies targeting OLs, myelin, and their receptors should be given more emphasis to attenuate ischemia injury and establish functional recovery after stroke. This review summarizes recent advances on the function of OLs in ischemic injury, as well as the present and emerging principles that serve as the foundation for protective strategies against OLs deaths.
Topics: Humans; Ischemic Stroke; Oligodendroglia; Myelin Sheath; Central Nervous System; Stroke
PubMed: 37321419
DOI: 10.1016/j.nbd.2023.106200