JUN Regulation of Injury-induced Enhancers in Schwann Cells
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ABSTRACT:
PROVIDER: PRJNA862057 | ENA |
REPOSITORIES: ENA
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Project description:The striking PNS regenerative response to injury rests on the plasticity of adult Schwann cells and their ability to transit between differentiation states, a highly unusual feature in mammals. Using mice with inactivation of Schwann cell c-Jun, we show that the injury response involves c-Jun dependent natural reprograming of differentiated cells to generate a distinct Schwann cell state specialized to promote regeneration. Transected distal stumps of c-Jun mutants show 172 disregulated genes, resulting in abnormal expression of growth factors, adhesion molecules and cytoskeletal changes that lead to neuronal death, inhibition of axon growth and striking failures of functional repair after injury. These observations provide a molecular basis for understanding Schwann cell plasticity and nerve regeneration. They offer conclusive support for the notion that Schwann cells control repair in the PNS, using dedicated transcriptional controls to generate a distinct repair cell, a transition that shows similarities to transdifferentiation seen in other systems. Total RNA was purified from a 10mm segment of the distal stump and uninjured contralateral nerve from c-Jun mutants and control mice 7 days after nerve cut. For each condition (injured/uninjured) and genotype (control/ knock-out) 2 independent samples (replicates) were generated from pooled nerves of 4/6 mice resulting in a total of 8 samples: CTRL.cut.R1, CTRL.cut.R2, CTRL.uncut.R1, CTRL.uncut.R2, KO.cut.R1, KO.cut.R2, KO.uncut.R1,KO.uncut.R2.
2012-06-13 | E-GEOD-38693 | biostudies-arrayexpress
Project description:Schwann cells play a critical role after peripheral nerve injury by clearing myelin debris, forming axon-guiding bands of Büngner, and remyelinating regenerating axons. Schwann cells undergo epigenomic remodeling to differentiate into a repair state that expresses unique genes, some of which are not expressed at other stages of Schwann cell development. We previously identified a set of enhancers that are activated in Schwann cells after nerve injury, and we determined whether these enhancers are preprogrammed into the Schwann cell epigenome as poised enhancers before injury. Poised enhancers share many attributes of active enhancers, such as open chromatin, but are marked by repressive histone H3 lysine 27 (H3K27) trimethylation rather than H3K27 acetylation. We find that most injury-induced enhancers are not marked as poised enhancers before injury indicating that injury-induced enhancers are not preprogrammed in the Schwann cell epigenome. Injury-induced enhancers are enriched with AP-1 binding motifs, and the c-JUN subunit of AP-1 had been shown to be critical to drive the transcriptional response of Schwann cells after injury. Using in vivo chromatin immunoprecipitation sequencing analysis in rat, we find that c-JUN binds to a subset of injury-induced enhancers. To test the role of specific injury-induced enhancers, we focused on c-JUN-binding enhancers upstream of the Sonic hedgehog (Shh) gene, which is only upregulated in repair Schwann cells compared with other stages of Schwann cell development. We used targeted deletions in male/female mice to show that the enhancers are required for robust induction of the Shh gene after injury.SIGNIFICANCE STATEMENT The proregenerative actions of Schwann cells after nerve injury depends on profound reprogramming of the epigenome. The repair state is directed by injury-induced transcription factors, like JUN, which is uniquely required after nerve injury. In this study, we test whether the injury program is preprogrammed into the epigenome as poised enhancers and define which enhancers bind JUN. Finally, we test the roles of these enhancers by performing clustered regularly interspaced short palindromic repeat (CRISPR)-mediated deletion of JUN-bound injury enhancers in the Sonic hedgehog gene. Although many long-range enhancers drive expression of Sonic hedgehog at different developmental stages of specific tissues, these studies identify an entirely new set of enhancers that are required for Sonic hedgehog induction in Schwann cells after injury.
| S-EPMC9410756 | biostudies-literature
Project description:Two mouse lines, OE/+ and OE/OE were generated expressing graded elevation (6 fold and 28 fold, respectively) of c-Jun protein selectively in Schwann cells. The effects of this on global gene expression and cellular structure in uninjured nerves was analysed during development and in the adult. Changes in gene expression and cellular arrangements were mild but detectable in c-Jun OE/+ mice, while nerves in c-Jun OE/OE mice showed obvious de-myelination and gene expression changes, including up- and down-regulation of genes previously shown to be controlled by c-Jun in Schwann cells.
2017-10-16 | E-MTAB-6138 | biostudies-arrayexpress
Project description:After nerve injury, myelin and Remak Schwann cells reprogram to repair cells specialized for regeneration. Normally providing strong regenerative support, these cells fail in aging animals, and during the chronic denervation that results from slow axon growth. This impairs axonal regeneration and causes a significant clinical problem. We find that aging and chronically denervated repair cells express reduced c-Jun protein and the regenerative support provided by these cells is also reduced. In both cases, genetically restoring Schwann cell c-Jun levels restores regeneration to that in controls. We identify potential gene candidates mediating this effect and implicate Shh in the control of Schwann cell c-Jun levels. These experiments reveal that a common mechanism, reduced c-Jun in repair cells, underlies two major reasons for regeneration failure in the PNS. They underscore the central importance of Schwann cell c-Jun as a regulator of nerve repair, and point to molecular pathways that can be manipulated for improving the clinical outcome of nerve injuries.
2020-10-14 | E-MTAB-9640 | biostudies-arrayexpress
Project description:The striking PNS regenerative response to injury rests on the plasticity of adult Schwann cells and their ability to transit between differentiation states, a highly unusual feature in mammals. Using mice with inactivation of Schwann cell c-Jun, we show that the injury response involves c-Jun dependent natural reprograming of differentiated cells to generate a distinct Schwann cell state specialized to promote regeneration. Transected distal stumps of c-Jun mutants show 172 disregulated genes, resulting in abnormal expression of growth factors, adhesion molecules and cytoskeletal changes that lead to neuronal death, inhibition of axon growth and striking failures of functional repair after injury. These observations provide a molecular basis for understanding Schwann cell plasticity and nerve regeneration. They offer conclusive support for the notion that Schwann cells control repair in the PNS, using dedicated transcriptional controls to generate a distinct repair cell, a transition that shows similarities to transdifferentiation seen in other systems.
2012-06-14 | GSE38693 | GEO
Project description:After peripheral nerve injury, adult Schwann cells convert to progenitor cell-like repair Schwann cells, which are pivotal for nerve regeneration. We show that Schwann cell-specific deletion of TFEB/3 disrupts the transcriptomic reprogramming necessary for injury-induced repair Schwann cell generation in mice. The mutant mice fail to generate proliferating repair Schwann cells to populate the injured nerves. Distal Schwann cells fail to express injury-responsive genes and continue to maintain the expression of myelin-associated genes. TFEB/3 binding motifs are enriched in injury-induced enhancers, suggesting their role in repair gene activation. Autophagy-dependent myelin breakdown is not impaired in the mutant mice despite the known function of TFEB/3 as autophagy activators. However, the mutant mice exhibit defects in axon regeneration, target reinnervation, and functional recovery. Therefore, TFEB/3 play a critical role in orchestrating transcriptional changes essential for repair Schwann cell generation and function necessary for peripheral nerve regeneration.
2024-08-12 | GSE249114 | GEO
Project description:Schwann cell (Büngner) repair cells play a critical role in orchestrating nerve repair after injury, but the reprogramming process that generates them is poorly understood. We present the first combined whole genome coding and non-coding RNA and CpG methylation study after nerve injury. We show that genes involved in epithelial to mesenchymal transition are enriched in repair cells and we identify long non-coding RNAs in Schwann cells. We demonstrate that the AP-1 transcription factor c-Jun regulates the expression of certain micro RNAs in repair cells, in particular miR-21 and miR-34. Surprisingly, changes in CpG methylation are limited in injury, unlike development, and restricted to specific locations, such as enhancer regions of novel Schwann cell specific genes, such as Nedd4l, and near to local enrichment of AP-1 motifs. These epigenetic changes significantly broaden our understanding of Schwann cell reprogramming in peripheral nervous system tissue repair. To identify epigenetic regulators underlying successful nerve regeneration we generated RNA-Seq, small-RNA-Seq and whole genome bisulfite sequencing libraries for uninjured nerve versus three and/or seven day post nerve transection sciatic nerves of adult C57BL/6J mice crush.
2017-08-30 | E-MTAB-5633 | biostudies-arrayexpress
Project description:To determine gene expression differences between control transected sciatic nerves (from C57BL/6 WT mice) and mutant (Homozyous Shh 1/2/3 enhancer deletion). Our analysis revealed significant differential gene expression between the control samples and the mutants.
2022-07-27 | GSE209658 | GEO
Project description:We report the transcriptome analysis of control and c-Jun knock-out HEI-286 human Schwann cells in presence or absence of cancer cells
2024-07-19 | GSE180710 | GEO
Project description:To further dissect whether and how activated JUN reconfigures the chromatin landscape, we performed Chromatin Immunoprecipitation (ChIP)-seq analyses for H3K4me1 and H3K27ac. Based on the significant increase of H3K27ac levels at H3K4me1+ sites, we identified 3,017 JUN-activated enhancers in JUN WT cells. In contrast, JUN AA fails to significantly induce H3K27ac accumulation at these regions. Their enrichment levels at JUN-activated enhancers were significantly decreased after JNKi treatment. Besides, these enhancers are directly driven by JUN, especially phosphorylated JUN.
2022-12-09 | GSE196345 | GEO