Comprehensive analysis of hypoxia-dependent expression of myelin-related genes in Schwann cells
Ontology highlight
ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE254040 | GEO | 2025/08/06
REPOSITORIES: GEO
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Project description:Inflammation and dysregulation of the immune system are hallmarks of several neurodegenerative diseases. An activated immune response is considered to be the cause of myelin breakdown in demyelinating disorders. In the peripheral nervous system (PNS), myelin can be degraded in an autophagy-dependent manner directly by Schwann cells or by macrophages, which are modulated by T-lymphocytes. Here, we show that the NF-κB activator Pleckstrin homology containing family member 5 (Plekhg5) is involved in the regulation of both Schwann cell autophagy and recruitment of T-lymphocytes in peripheral nerves during motoneuron disease. Plekhg5-deficient mice show defective axon/Schwann cell units characterized by myelin infoldings in peripheral nerves. Even at late stages, Plekhg5-deficient mice do not show any signs of demyelination and inflammation. Using RNAseq, we identified a transcriptional signature for an impaired immune response in sciatic nerves, which manifested in a reduced number of CD4+ and CD8+ T-cells. These findings identify Plekhg5 as a promising target to impede myelin breakdown in demyelinating PNS disorders.
2020-07-27 | GSE127319 | GEO
Project description:Schwann cells (SC) are essential to the growth, maintenance and regeneration of peripheral nerves, but the proteome of normal human SC is poorly defined. Here, we performed a proteomic analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) to identify the protein expression profile of primary human SC. A total of 19,557 peptides corresponding to 1,553 proteins were identified, with 1% false discovery rate (FDR). Ingenuity Pathway Analysis (IPA), Gene Ontology (GO) and Database for Annotation, Visualization and Integrated Discovery (DAVID) were used to assign protein localization and function, and to define enriched pathways. EIF2, mTOR and integrin signalling were among the most enriched pathways and the most enriched biological function was cell-cell adhesion, which is in agreement with the supportive role of SC in peripheral nerves. This proteome analysis of normal human SC may help in the molecular exploration of neurological and malignant diseases where SC are involved.
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Project description:The core component of the class III phosphatidylinositol 3-kinase complex, Beclin 1, takes part in different protein networks, thus switching its role from inducing autophagy to regulating autophagosomal maturation and endosomal trafficking. While assessed in neurons, astrocytes and microglia, its role was far less investigated in myelinating glia, including Schwann cells (SCs), responsible for peripheral nerve myelination. Remarkably, the dysregulation in endosomal trafficking is emerging as a pathophysiological mechanism underlying peripheral neuropathies, such as demyelinating Charcot-Marie-Tooth diseases. By knocking out Beclin 1 in SCs we here generated a novel mouse model (Becn1 cKO), developing a severe and progressive neuropathy, accompanied by involuntary tremors, body weight loss and premature death. Ultrastructural analysis revealed abated myelination and SCs displaying enlarged cytoplasm with progressive accumulation of intracellular vesicles. Transcriptomic and histological analysis from sciatic nerves of 10-day and 2-month-old mice revealed pro-mitotic gene deregulation and increased SCs proliferation at both stages with axonal loss and increased immune infiltration in adults, well reflecting the progressive motor and sensory functional impairment that characterizes Becn1 cKO mice, compared to controls. Our study establishes a further step in understanding key mechanisms in SC development and points to Beclin 1 and its regulated pathways as targets for demyelinating CMT forms. A novel conditional gene knockout was generated to investigate the role that Beclin 1 exerts in Schwann cells and in myelination. The newly generated mouse line resulted in a model for severe and progressive peripheral neuropathy. Together with defective myelination, we described radial sorting defects, motor and sensory neuron impairments, immune infiltrate in adults and a huge transcripts deregulation. The emerged deregulated signalling pathways highlighted how Beclin 1 is able to coordinate integrated signaling pathways essential for Schwann cell maturation and nerve development and homeostasis.
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Project description:Schwann cell (SC) myelination in the peripheral nervous system is essential for motor function, and uncontrolled SC proliferation occurs in cancer. Here, we show that a dual direct role for Hippo effectors TAZ and YAP in regulation of SC proliferation and myelination through modulating G protein expression and interacting with SOX10, respectively. Developmentally-regulated mutagenesis indicates that TAZ/YAP are critical for SC proliferation yet also required for their differentiation and myelination. Genome-wide occupancy mapping and transcriptome profiling reveal that nuclear TAZ and YAP promote SC proliferation by activating cell cycle regulators, while targeting critical differentiation regulators in cooperation with SOX10 for myelination. We further identified that TAZ targets and represses Gnas, encoding Gαs-protein, which opposes TAZ/YAP activities to decelerate proliferation. Gnas deletion expands SC precursor pools and blocks myelination in the sciatic nerve. Thus, our study revealed that the Hippo/TAZ/YAP and Gαs-protein feedback circuit functions as a fulcrum balancing SC proliferation and differentiation, providing insights into molecular programming of SC lineage progression and homeostasis.
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Project description:Axonal myelination is essential for neuronal function and health. In peripheral nerves, deficient myelination is responsible for the morbidity of various forms of inherited or acquired neuropathies, including Charcot-Marie-Tooth disease and diabetic neuropathy. Decades of research have uncovered a complex transcriptional and post-transcriptional program that co-ordinates the formation and maintenance of the myelin sheath. In contrast, much less is known about the functional role of post-translational modification (PTM) of proteins in this remarkable biogenic process. Neddylation, a PTM that involves the conjugation of the ubiquitin-like protein Nedd8 to protein targets, has recently emerged as a central and versatile regulator of many cellular processes, including gene transcription, metabolism, and cellular differentiation. In this study, we show that genetic and pharmacological inhibition of neddylation in vivo in developing Schwann cells lead to striking nerve defects that exhibit the classical hallmarks of a severe neuropathy, including gait abnormalities, muscle weakness, and hindlimb clasping, ultimately leading to early death. The mutant mice lack peripheral myelin and develop secondary axonal loss, and we demonstrate, at the mechanistic level, that neddylation regulates multiple critical myelination-related pathways. Together, our findings identify neddylation as a central regulatory hub of control of peripheral myelination and delineate the potential pathogenetic mechanisms in inherited human PNS disorders, characterized by mutations in genes related to the neddylation pathway.
2024-06-16 | PXD043917 | Pride
Project description:Activation of mTOR signaling by Tsc1 ablation during early developmental stages increases SC proliferation and delays radial sorting, while causing hypomyelination in the PNS. However, knockout Tsc1 in myelinating SCs at postnatal stages promotes myelin overgrowth and outfoldings. Sustained mTOR pathway leads to activation of the PLK signaling pathway. mTOR attenuation or pharmacological inhibition of PLK1 could partially rescue myelination defects in Tsc1 mutant sciatic nerves. Our data suggest that TSC1-mTOR maintains the homeostasis of SC proliferation and differentiation in a stage-specific manner.
2018-09-05 | GSE103957 | GEO
Project description:Elucidating the genes regulated during cell-cell communication remains fascinating considering the importance of cell recognition and downstream signaling through development and in many diseases. In the peripheral nervous system, the interaction between Schwann cells (SCs) and axons is crucial as it allows their survival and induces SCs to differentiate and engage a process of myelination. To get further insight the molecular mechanisms resulting from this cell interaction, comparative gene analysis between SCs and SCs co-cultured with DRG neurons were performed and led us to identify a set of 32 genes regulated in SCs in the early stage of neuron-SC contact. Expression of several candidates were analyzed by QPCR during development and we demonstrate using a blocking antibody approach in an in vitro myelination assay that one candidate was not only upregulated in response to axonal contact but also controls peripheral myelination. Three biological replicates each in dye swap for 22k slides and two biological replicates each in dye swap for NeuroDev2
2011-01-15 | E-GEOD-17366 | biostudies-arrayexpress
Project description:Understanding the regulation of oligodendrocyte development and myelination in the central nervous system (CNS) is essential, not only to facilitate myelin repair but also to define the role of oligodendrocytes in maintaining axonal integrity. In vitro studies have implicated astrocytes in influencing multiple aspects of oligodendrocytes and their precursors, however the in vivo role of astrocytes in myelination and myelin repair remain poorly defined. We show that astrocyte ablation during postnatal spinal cord development resulted in a concomitant delay in myelination, demonstrating a critical role for astrocytes in promoting developmental myelination. By contrast, in the adult CNS, localized ablation of astrocytes 2 days after a demyelinating insult resulted in increased numbers of oligodendrocytes and accelerated remyelination in both the spinal cord and the corpus callosum. Microarray analysis reveals astrocytic NF-kB signaling pathway as a major contributor to pathological events occurring after demyelination. We suggest that the localized functions of astrocytes are fundamentally different during developmental myelination and myelin repair. Astrocytes are critical for developmental myelination, however in a demyelinating environment they are detrimental to myelin repair.
2017-08-01 | GSE60276 | GEO
Project description:The myelin sheaths that surround the thick axons of the peripheral nervous system are produced by the highly specialized Schwann cells. Differentiation of Schwann cells and myelination occur in discrete steps. Each of these requires coordinated expression of specific proteins in a precise sequence, yet the regulatory mechanisms controlling protein expression during these events are incompletely understood. Here we report that Schwann cell-specific ablation of the enzyme Dicer1, which is required for the production of small non-coding regulatory microRNAs, fully arrests Schwann cell differentiation, resulting in early postnatal lethality. Dicer-/- Schwann cells had lost their ability to myelinate, yet were still capable of sorting axons. Both cell death and, paradoxically, proliferation of immature Schwann cells was vastly enhanced, suggesting that their terminal differentiation is triggered by growth-arresting regulatory microRNAs. Using microRNA microarrays, we identified 16 miRNAs that are upregulated upon myelination and whose expression is controlled by Dicer in Schwann cells. This set of microRNAs appears to drive Schwann cell differentiation and myelination of peripheral nerves, thereby fulfilling a crucial function for survival of the organism. Samples representing Schwann cell-specific ablation of the enzyme Dicer1 and wild type controls at developmental stages E17 and P4. Geometric mean-averaged data linked below as supplementary file.
2010-12-01 | E-GEOD-22023 | biostudies-arrayexpress
Project description:Hypoxia-inducible factor (HIF) is a master regulator of cancer cell adaptation to tumor hypoxia and is involved in cancer progression. Single-cell (sc) differences in the HIF response allow for tumor evolution and cause therapy resistance. These sc-differences are usually ascribed to tumor microenvironmental differences and/or clonal (epi)genetic variability. However, the sc-heterogeneity of the HIF response in otherwise identical clonal cells cultured under defined in vitro conditions has not yet been addressed. Therefore, we generated clonal HIF-1α- or HIF-2α-deficient cell lines and analyzed the sc-response to hypoxia. While HIF-1α and HIF-1 target mRNA sc-heterogeneity was slightly higher than global transcription or specific housekeeping mRNAs, HIF-2α and especially HIF-2 target mRNA sc-heterogeneity was extraordinary, and remained in independent subclones as well as following Isoform-specific HIFα ablation. Unexpectedly, neither HIF-2α mRNA nor nuclear protein levels correlated with target mRNA levels. Unsupervised but not supervised HIF target gene dimensionality reduction revealed the initial sample composition after scRNAseq, demonstrating that, owing to sc-heterogeneity, individual HIF target genes are not sufficient to unequivocally identify hypoxic cancer cells. In conclusion, the pronounced intrinsic sc-heterogeneity of the HIF response represents a hitherto unrecognized feature of cancer cells that impairs clinical HIF pathway-dependent cancer cell identification and targeting.
2025-03-29 | GSE292771 | GEO