Project description:Schwann cells are important glial cells in peripheral nervous system. In this study, we performed single cell RNA-sequencing (scRNA-seq) analysis of Schwann cells exist in both dorsal root ganglion(DRG) and sciatic nerve.We categorized DRG and sciatic nerve Schwann cells into different subtypes,and found common subtypes and different subtypes.In addition, we discovered the proliferation and migration ability of Schwann cells were distinct in different tissues.Our current study revealed the distinctive characteristics of Schwann cells in DRG and sciatic nerve.
Project description:ChIP-seq of H3K27ac in P15 sciatic nerve was used to identify actively engaged enhancers in Schwann cells, which constitute the majority of nuclei in peripheral nerve.
Project description:Early molecular events related to cytoskeleton are poorly described in Amyotrophic Lateral Sclerosis (ALS), especially in the Schwann cell (SC), which offers strong trophic support to motor neurons. DAVID tool identified cytoskeleton-related genes by employing the Cellular Component of Gene Ontology (CCO) in a large gene profiling of lumbar spinal cord and sciatic nerve of presymptomatic SOD1G93A mice. One and five CCO terms related to cytoskeleton were described from the spinal cord deregulated genes of 40 days (actin cytoskeleton) and 80 days (microtubule cytoskeleton, cytoskeleton part, actin cytoskeleton, neurofilament cytoskeleton and cytoskeleton) old transgene mice, respectively. Also, four terms were depicted from the deregulated genes of sciatic nerve of 60 days old transgenes (actin cytoskeleton, cytoskeleton part, microtubule cytoskeleton and cytoskeleton). Kif1b was the unique gene that appeared deregulated in more than one studied region or presymptomatic age. The expression of Kif1b (qPCR) elevated in the lumbar spinal cord (40 days old) and decreased in the sciatic nerve (60 days old) of presymptomatic ALS mice, results that were in line to microarray findings. Upregulation (24.8 fold) of Kif1b was seen in laser microdissected enriched immunolabeled motor neurons from the spinal cord of 40 days old presymptomatic SOD1G93A mice. Furthermore, Kif1b was downregulated in the sciatic nerve Schwann cells of presymptomatic ALS mice (60 days old) that were enriched by means of cell microdissection (6.35 fold), cell sorting (3.53 fold) and primary culture (2.70 fold) technologies. The gene regulation of cytoskeleton molecules is an important occurrence in motor neurons and Schwann cells in presymptomatic stages of ALS and may be relevant in the dying back mechanisms of neuronal death. Differential regulation of Kif1b in the spinal cord and sciatic nerve cells emerged as key event in ALS. Sciatic nerve from SOD1G93A and Non transgenic controls from 60 days were used in the experiments. 4 biological replicates were used. A reference sample, comprised by RNA from different neonatal organs (heart, liver, kidney) were used in the hybridations
Project description:Sciatic nerve ligation was performed on cohorts of 2-month and 24-month old animals. Resulting gene-expression data were generated from sciatic nerve 1 and 4 days after injury compared to naïve animals. Results show differences in sciatic nerve responses with normal aging. Total RNA taken from sciatic nerves from 2-month and 24-month old animals at either day 0, 1 and 4 after sciatic nerve crush injury.
Project description:To address the role of INO80/SWR-type remodeling complexes, we deleted Ep400 in developing Schwann cells. Ep400 becomes important for proper Schwann cell development at differentiation. Its absence in Schwann cells leads to a peripheral neuropathy. RNA-Seq studies were performed on sciatic nerve from control mice and mice with a Schwann cell-specific deletion of Ep400 to analyze changes in gene expression. These revealed substantial changes in the expression of genes associated with immune and inflammatory response, myelination-associated lipid metabolism and developmental regulatory genes whose occurrence and action is normally limited to earlier stages of development.
Project description:Sciatic nerve axon segments from adult mouse were isolated. Following enzymatic digestion, lysate was subjected to incubation with beads conjugated with either clathrin heavy chain antibody or control IgG antibody for clathrin immunoprecipitation. MudPIT analysis was subsequently performed to identify proteins co-precipitating with clathrin.
Project description:Lysine acetylation is a reversible Post-translational modification (PTM) involved in a broad array of physiological functions. Recent studies have demonstrated the involvement of protein acetylation in modulating Schwann cells' (SCs) biology and the peripheral nervous system (PNS) regeneration. However, the underlying mechanism is still under investigation. This descriptive study characterized the mouse sciatic nerve (SN) acetylome and explored their cellular distribution. Using a modified workflow for acetylome analysis, we identified 483 acetylated proteins containing 1,442 acetylation modification sites in the SN of adult C57BL/6. Notably, over 70% of identified peptides were acetylated. Bioinformatic analysis suggested that these acetylated proteins are mainly located in the myelin sheath, mitochondrial inner membrane, and actin cytoskeleton, and highlighted the remarkable differences between the mouse SN and brain (PXD027299)acetylome. Further manual annotation indicated that most acetylated proteins were mitochondrial and energy, and cytoskeleton and cell adhesion (> 45%). The acetylate modification of three novel myelin-related proteins were verified, including 2', 3' -cycling-nucleotide 3'-phosphodiesterase (CNP), Neurofilament light polypeptide (NEFL), neurofilament medium/high polypeptide (NFM/H), and periaxin (PRX). Immunofluorescence staining illustrated that, besides the nuclei, the acetylated proteins, including acetylated alpha-tubulin, were mainly co-localized with S100 positive SCs. Together, for the first time, this study provided a comprehensive mouse SN acetylome by using a simple but effective method. Moreover, we demonstrated that the acetylated SN proteins were predominantly located in SCs. These analyses and the method will contribute to understanding and uncovering the roles of protein acetylation in SCs development and PNS regeneration.
Project description:The regenerative capacity of peripheral nerves declines during aging, contributing to the development of neuropathies, limiting organism function. Changes in Schwann cells prompt failures in instructing maintenance and regeneration of aging nerves; altered inflammatory environment leading to a defective Schwann cell response, as an underlying mechanism of impaired nerve regeneration during aging. Chronic inflammation was detected in intact uninjured old nerves, characterized by increased macrophage infiltration and raised levels of monocyte chemoattractant protein 1 (MCP1) and CC chemokine ligand 11 (CCL11). Schwann cells in the old nerves appeared partially dedifferentiated, accompanied by an activated repair program independent of injury. Upon sciatic nerve injury, an initial delayed immune response was followed by a persistent hyperinflammatory state accompanied by a diminished repair process. As a contributing factor to nerve aging, we showed that CCL11 interfered with Schwann cell differentiation in vitro and in vivo. Our results indicate that increased infiltration of macrophages and inflammatory signals diminish regenerative capacity of aging nerves by altering Schwann cell behavior. The study identifies CCL11 as a promising target for anti‐inflammatory therapies aiming to improve nerve regeneration in old age.
Project description:Wallerian degeneration (WD) involves the fragmentation of axonal segments disconnected from their cell bodies, segmentation of the myelin sheath, and removal of debris by Schwann cells and immune cells. The removal and downregulation of myelin-associated inhibitors of axonal regeneration and synthesis of growth factors by these two cell types are critical responses to successful nerve repair. Here, we analyzed the transcriptome of the sciatic nerve of mice carrying the Wallerian degeneration slow (WldS) mutant gene, a gene that confers axonal protection in the distal stump after injury, therefore causing significant delays in WD, neuroinflammation, and axonal regeneration. 56 C57BL6 mice and 56 C57BL/6 OlaHsd-Wlds mice were anesthetized with isoflurane and underwent a microcrush lesion of their left sciatic nerve at the mid-thigh level (exept naive mice, t0). At 0, 3, 7 and 14 days post-injury, mice were anesthetized and killed by cervical dislocation. Sciatic nerves were collected and conective tissue removed. A 4-mm long sciatic nerve segment was taken from the nerve distal stump, starting at 1 mm distal from the lesion up to 5 mm distal. Distal nerve stumps were pooled by group and RNA extracted. Samples were hybridized to GeneChip® Mouse Genome 430 2.0 Array (Affymetrix). Biological replicate was done.