Similar Datasets
Project description:Temporal Changes in Macrophage Phenotype after Peripheral Nerve Injury
| PRJNA417027 | ENA
Project description:BACKGROUND:Macrophages play a key role in peripheral nerve repair and demonstrate complex phenotypes that are highly dependent on microenvironmental cues. METHODS:We determined temporal changes in macrophage gene expression over time using RNA sequencing after fluorescence-activated cell sorting (FACS) macrophage populations from injured peripheral nerve. We identified key upstream regulators and dominant pathways using ingenuity pathway analysis and confirmed these changes with NanoString technology. We then investigate the effects of extreme polarizers of macrophage phenotype (IL4 and IFNγ) on nerve regeneration. We determined macrophage gene expression in vivo at the site of peripheral nerve injury with NanoString technology, and assessed recovery from sciatic nerve injury by cranial tibial muscle weights and retrograde labeling motor neurons in mice with deletion of IL4 or IFNγ receptors. RESULTS:We demonstrate that IL4R and IFNγR deletions provide complementary responses to polarization, and alter expression of genes associated with angiogenesis and axonal extension, but do not influence recovery from peripheral nerve transection at 8 weeks after repair. CONCLUSIONS:Overall, this study provides a framework to evaluate the phenotype of macrophages over time, and provides a broader and more precise assessment of gene expression changes than has previously been commonly used. This data suggests ways in which polarization may be modulated to improve repair.
| S-EPMC6003127 | biostudies-literature
Project description:ChIP-seq of H3K27acetylation in sham and injured nerve. Schwann cells play an important role in the response of peripheral nerve to injury. This study was designed to identify enhancers that are altered in sciatic nerve at 3 days post-injury to help identify pathways that mediate the gene expression reprogramming that occurs in Schwann cells after nerve injury. We employed ChIP-seq analysis of H3K27 acetylation as a mark of actively engaged enhancers, and compared enhancers in the distal stump of transected sciatic nerve compared to contralateral (sham) condition.
2014-12-15 | GSE63103 | GEO
Project description:Transcriptional changes are distinct in female and male mice in the time course of peripheral nerve injury response. Here, we present sexually dimorphic transcriptome profiles established in the space of 24 h period after sciatic nerve axotomy.
2022-07-18 | GSE182713 | GEO
Project description:In vertebrates, the peripheral nervous system has retained its regenerative capacity, enabling severed axons to reconnect with their original synaptic targets. While it is well documented that a favorable environment is critical for nerve regeneration, the complex cellular interactions between injured nerves with cells in their environment, as well as the functional significance of these interactions, have not been determined in vivo and in real time. Here we provide the first minute-by-minute account of cellular interactions between laser transected motor nerves and macrophages in live intact zebrafish. We show that macrophages arrive at the lesion site long before axon fragmentation, much earlier than previously thought. Moreover, we find that axon fragmentation triggers macrophage invasion into the nerve to engulf axonal debris, and that delaying nerve fragmentation in a Wld(s) model does not alter macrophage recruitment but induces a previously unknown 'nerve scanning' behavior, suggesting that macrophage recruitment and subsequent nerve invasion are controlled by separate mechanisms. Finally, we demonstrate that macrophage recruitment, thought to be dependent on Schwann cell-derived signals, occurs independently of Schwann cells. Thus, live cell imaging defines novel cellular and functional interactions between injured nerves and immune cells.
| S-EPMC3324096 | biostudies-other
Project description:Foreign body reaction is one of the most important limiting factors to the clinical translation of implantable bioelectronics. The experiment compares the process of foreign body reaction, following the implantation of a silicon device in a mouse peripheral nerve, to that of peripheral nerve injury, following nerve crushing. Both processes are also compared to a naïve peripheral nerve from an uninjured mouse. The endpoints are day 1, 4, 7, 14 and 28 days.
2022-04-30 | E-MTAB-10294 | biostudies-arrayexpress
Project description:Website for easy exploration of the data: https://rna-seq-browser.herokuapp.com/# For the first time, we here characterize the transcriptional signature of satellite glial cells (SGCs) in a nerve injury-paradigm by isolating SGCs from mouse dorsal root ganglia (DRGs) after peripheral nerve injury followed by next generation RNA sequencing (RNA-seq). We found that SGCs regulate their gene expression differently at 3 days and 14 days after peripheral nerve injury suggesting that they change their function over time. At both time points, we found downregulation of several genes linked to cholesterol. After 14 days we further detect regulation of genes linked to the immune system (MHC protein complex and leukocyte migration). The SGC RNA-seq data is accompanied by RNA-seq of purified nociceptors from injured (partial sciatic nerve ligation) or sham (ipsi after sham operation or contra after partial sciatic nerve ligation) L3-L5 DRGs.
2020-01-22 | GSE120284 | GEO
Project description:Peripheral nerve repair across long gaps remains clinically challenging despite progress made with autograft transplantation. While scaffolds that present trophic factors and extracellular matrix molecules have been designed, matching the performance of autograft-induced repair has been challenging. In this study, we explored the effect of cytokine mediated 'biasing' of macrophage phenotypes on Schwann cell (SC) migration and axonal regeneration in vitro and in vivo. Macrophage phenotype was successfully modulated by local delivery of either Interferon-gamma (IFN-γ) or Interleukin-4 (IL-4) within polymeric nerve guidance channels, polarizing them toward pro-inflammatory (M1) or pro-healing (M2a and M2c) phenotypes, respectively. The initial polarization of macrophages to M2a and M2c phenotype results in enhanced SC infiltration and substantially faster axonal growth in a critically-sized rat sciatic nerve gap model (15 mm). The ratio of pro-healing to pro-inflammatory population of macrophages (CD206+/CCR7+), defined as regenerative bias, demonstrates a linear relationship with the number of axons at the distal end of the nerve scaffolds. The present results clearly suggest that rather than the extent of macrophage presence, their specific phenotype at the site of injury regulates the regenerative outcomes.
| S-EPMC3483037 | biostudies-literature
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:Hyaluronic acid (HA) is ubiquitously found in biological tissues and mediates wound healing mechanisms after injury by promoting cell migration and proliferation. With the development of tissue-engineered neural therapeutics, including off-the-shelf grafts for peripheral nerve repair, HA is an attractive material for clinical use because of its various biological roles. HA-based biomaterials have been carefully engineered to elicit specific in vivo host responses, however an important design feature that should be considered in these scaffolds is endogenous degradation. Hyaluronidases (HYALs) are the complementary enzymes that are responsible for HA turnover. Although HYAL expression has been widely characterized in various tissues, including the central nervous system, and for different pathologies, there remains a lack of knowledge of HYAL mediated turnover in peripheral nerve tissue. In this work, gene expression of two hyaluronidases, HYAL1 and HYAL2, and HA-binding receptor, CD44, were studied in two injury models: rat sciatic nerve crush and critical gap transection. HYAL2 and CD44 were shown to be upregulated 3 days after crush injury, whereas HYAL1 was upregulated at 3 weeks, which collectively demonstrate temporal patterning of HA breakdown. Additionally, differences were observed between HYAL and HA expression at 3 weeks when compared for both nerve injury models. The activity of HYAL in peripheral nerve tissue was determined to be approximately 0.11 μmol/min, which could be used to further model HA-based biomaterial breakdown for peripheral nerve applications. Overall, this work provides a landscape of HA turnover in peripheral nerve that can be used for future neural applications.
| S-EPMC10449126 | biostudies-literature