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.
Project description:Systematic analyses of the temporal dynamics of transcriptomes and chromatin landscapes of macrophages during timecourse of TLR4-mediated inflammatory response. As a multifunctional effector cell, macrophages play pivotal roles in both the induction and resolution components of varied inflammatory processes. During the course of an inflammation response, macrophages engage in a homeostatic program characterized by tightly coordinated modulation of temporal outputs of both lipid metabolism and inflammation. We demonstrate inversely biphasic temporal dynamics of specific fatty acid metabolic and inflammatory gene expression profiles, associated with concordant temporal reprogramming of macrophage fatty acid profiles. In part, the late phase of the macrophage inflammatory response is characterized by tailoring of fatty acid related gene expressions, facilitating both significant induction of anti-inflammatory unsaturated fatty acid production and associated resolution of inflammation. We demonstrate the biphasic temporal dynamics of macrophage inflammation, specifically anti-inflammatory omega-3 and omega-9 unsaturated fatty acid levels, are transcriptionally driven genome-wide by an unexpected shift from an LXR to SREBP1-dominant regulatory program in the late phase inflammatory response. Collectively, our findings reveal a novel Srebp1-driven mechanism allowing the intimate inverse temporal relationship between the transcriptional regulation of inflammatory and fatty acid metabolic outputs; whereby modulation key transcriptional regulators (LXR, SREBP1 and NF-kB) of these pathways coordinate appropriate temporal tailoring of local enhancer associated reprogramming and eventual pathway regulatory interactions, during the course of TLR4-dependent inflammatory response in macrophages. This specific Srebp-driven, temporal reprogramming of macrophage fatty acid metabolism, characterized by late phase induction of anti-inflammatory unsaturated fatty acid production, is necessary for appropriate resolution of inflammation. Thus, this study suggests that selective reprogramming of macrophage lipid metabolism can serve as a viable therapeutic intervention aimed at ameliorating chronic inflammation and varied metabolic syndrome associated states.
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.
Project description:Peripheral nerve injury alters the expression of hundreds of proteins in dorsal root ganglia (DRG). Targeting some of these proteins has led to successful treatments for acute pain, but not for sustained postoperative neuropathic pain. The latter may require targeting multiple proteins. Since a single microRNA (miR) can affect the expression of multiple proteins, here, we describe an approach to identify chronic neuropathic pain-relevant miRs. We used two variants of the spared nerve injury (SNI): Sural-SNI and Tibial-SNI and found distinct pain phenotypes between the two. Both models induced strong mechanical allodynia, but only Sural-SNI rats maintained strong mechanical and cold allodynia, as previously reported. In contrast, we found that Tibial-SNI rats recovered from mechanical allodynia and never developed cold allodynia. Since both models involve nerve injury, we increased the probability of identifying differentially regulated miRs that correlated with the quality and magnitude of neuropathic pain and decreased the probability of detecting miRs that are solely involved in neuronal regeneration. We found seven such miRs in L3-L5 DRG. The expression of these miRs increased in Tibial-SNI. These miRs displayed a lower level of expression in Sural-SNI, with four having levels lower than those in sham animals. Bioinformatics analysis of how these miRs could affect the expression of some ion channels supports the view that, following a peripheral nerve injury, the increase of the 7 miRs may contribute to the recovery from neuropathic pain while the decrease of four of them may contribute to the development of chronic neuropathic pain. The approach used resulted in the identification of a small number of potentially neuropathic pain relevant miRs. Additional studies are required to investigate whether manipulating the expression of the identified miRs in primary sensory neurons can prevent or ameliorate chronic neuropathic pain following peripheral nerve injuries. To identify the miRs that were differentially dysregulated between Tibial-SNI and Sural-SNI, we first performed 12 microarrays in a limited number of samples (in four individual DRGs per group: Sham, Tibial-SNI and Sural-SNI; two L3-DRG and two L4-DRG). Then, miRs identified as having differential expression were corroborated with real time qRT-PCR in RNA isolated from individual DRGs (L3, L4 and L5) derived from 4 rats per group (not presented here, but in the manuscript).
Project description:Peripheral nerve injuries are common in modern society. The patients may suffer from partial or total loss of sensory, motor and autonomic function in the involved segments of the body. However, The molecular mechanisms of the regeneration program has not yet been definitively clarified and the comprehensive lncRNA expression signature in peripheral nerve regeneration remains fully unknown.We performed a high throughput microarray assay to detect lncRNA expression profile in the distal end of peripheral nerve at 0,3,7,14 day after injury.
Project description:Japanese encephalitis (JE) is an acute encephalitis syndrome contributed to Japanese encephalitis virus (JEV) infection. It is the chief cause of viral encephalitis in Asian. In recent years, association of JEV infection with neurological problems such as Guillain-Barré syndrome had reported. Nevertheless, its potential pathogenic mechanism has never been reported. Therefore, it is urgent to explore the relationship between peripheral nerve injury and JEV infection. Here, we use the liquid chromatography-tandem mass spectrometry (LC-MS/MS) technique to make out the protein expression levels of mice sciatic nerve between JEV infection group and the sham group. In general, 4303 proteins were identified by MS, and 187 differentially expressed proteins were found. There were 105 proteins up-regulated in the injured sciatic nerve, and 82 proteins were down-regulated. Functional enrichment analysis of differentially expressed proteins showed that the up-regulated proteins were mainly related to immune regulatory response, and the down-regulated proteins were related to ribosomal structural components and translation.