Project description:Oxaliplatin-induced neuropathic pain is a common dose-limiting side effect of cancer treatment but the underlying mechanisms are largely unknown. The neuropathic pain model was established by oxaliplatin intraperitoneal administration for five consecutive days. In the present study, we performed whole genome expression microarray analysis by using spinal dorsal horn from oxaliplatin-treated and vehicle-treated rats on day 10.
Project description:As rats do not develop neuropathic pain like hypersensitivity as neonates post nerve injury but do as adults we have used these arrays to help define the processes involved in this process. Rat spinal cord (ipsilateral dorsal horn) was assayed 7 days post SNI injury to the sciatic nerve relative to sham injury. Two age groups of animals were tested Neonates (P10) and Adult (8-12wks). Experiment Overall Design: Six biologically indepenedent arrays were hybridized per assay point. Dorsal horn total RNA was prepared using standard Affymetrix protocols. Affymetrix Rat Expression 230A array used.
Project description:As rats do not develop neuropathic pain like hypersensitivity as neonates post nerve injury but do as adults we have used these arrays to help define the processes involved in this process. Rat spinal cord (ipsilateral dorsal horn) was assayed 7 days post SNI injury to the sciatic nerve relative to sham injury. Two age groups of animals were tested Neonates (P10) and Adult (8-12wks). Keywords: Two way analysis of differential regulation
Project description:Microglia in the spinal dorsal horn have been implicated in the pathogenesis of neuropathic pain following peripheral nerve injury. We have revently found that CD11c-expressing spinal microglia appear after the development of behavioral pain hypersensitivity following nerve injury and are essential for recovery from neuropathic pain. In order to better understand the gene expression profiles of CD11c-expressing microglia, we performed quantitative bulk RNA sequencing of microglia isolated from mice expressing Venus fluorescent protein under the control of CD11c promoter. We found that CD11c-expressing microglia show distinct gene expression profile compared to CD11c-negative microglia following nerve injury.
Project description:Clinical observations indicate that vitamin D is a pain alleviating molecule. In order to unveil the molecular mechanisms at play, we performed an experimental study on rats with a neuropathic pain. After three weeks of vitamin D treatment, the cerebrum, the spinal cord and the dorsal root ganglia were collected for a transcriptomic analysis, using cDNA microarrays.
Project description:Previous studies have suggested that astrocyte activation in the spinal dorsal horn may play an important role in the development of chronic neuropathic pain; but the mechanisms involved in astrocyte activation and their modulatory effects remain unknown. The inward rectifying potassium channel protein 4.1 (Kir4.1) is the most important background K+ channel in astrocytes. However, how Kir4.1 is regulated and contributes to behavioral hyperalgesia in chronic pain is unknown. In this study, single-cell RNA sequencing analysis indicated that the expression of Kir4.1 and Methyl-CpG-binding protein 2 (MeCP2) were both decreased in spinal astrocytes after chronic constriction injury (CCI) in a mouse model. Conditional knockout of the Kir4.1 channel in spinal astrocytes led to hyperalgesia; and overexpression of the Kir4.1 channel in spinal cord relieved CCI-induced hyperalgesia. Expression of spinal Kir4.1 after CCI was regulated by MeCP2. Electrophysiological recording in spinal slices showed that knockdown of Kir4.1 significantly regulated the excitability of astrocytes and then functionally changed the firing patterns of neurons in dorsal spinal cord. Therefore, targeting spinal Kir4.1 maybe an underlying treatment for hyperalgesia in chronic neuropathic pain.
Project description:Treating neuropathic pain is challenging and novel non-opioid based medicines are needed. Using unbiased receptomics, transcriptomic analyses, immunofluorescence and in situ hybridization, expression of the orphan GPCR (oGPCR) GPR160 increased in the rodent dorsal horn of the spinal cord (DH-SC) following traumatic nerve injury. Genetic and immunopharmacological approaches demonstrated that GPR160 inhibition in the spinal cord prevented and reversed neuropathic pain in male and female rodents without altering normal pain response. GPR160 inhibition in the spinal cord attenuated sensory processing in the thalamus, a key relay in the sensory discriminative pathways of pain. We also identified cocaine- and amphetamine-regulated transcript peptide (CARTp) as a GPR160 ligand. Inhibiting endogenous CARTp signaling in spinal cord attenuated neuropathic pain, whereas exogenous intrathecal (i.th.) CARTp evoked painful hypersensitivity through GPR160-dependent ERK and cAMP response element-binding protein (CREB). Our findings de-orphanize GPR160, identify it as a determinant of neuropathic pain and potential therapeutic target, and provide insights to its signaling pathways. CARTp is involved in many diseases including depression, reward and addiction, de-orphanization of GPR160 is a major step forward understanding the role of CARTp signaling in health and disease.
Project description:Background: The pathogenesis of neuropathic pain and the reasons for the prolonged unhealing are still unknown. Increasing evidence suggests that oestrogen sex differences play a role in pain sensitivity, but few studies focused on the role of oestrogen receptor which maybe an important molecular component contributing to peripheral pain transduction. We aimed to investigate the impact of ooestrogen receptors in nociceptive neuronal response in the dorsal root ganglion (DRG) and spinal dorsal horn using a spared nerve injury (SNI) rat model of chronic pain. Methods: We used a class of oestrogen receptors antagonists and agonists intrathecal (i.t.) administrated to male rats with SNI or normal rats to identify the main receptor. Moreover, we applied genes identified through genomic metabolic analysis to determine the key metabolism point and elucidate potential mechanisms mediating continuous neuronal sensitisation and neuroinflammation responses in neuropathic pain. The excitability of DRG neurons was detected using the patch clamp technique. Primary culture was used to extract microglia and DRG neurons, and siRNA transfection was used to silence receptor protein expression. Immunofluorescence, Western blotting, qPCR and behavioral testing were used to assess the expressions, cellular distributions, and actions of main receptor and its related signaling molecules. Results: Increasing the expression and function of G protein-coupled oestrogen receptor (GPER), but not oestrogen receptor-α (ERα) and oestrogen receptor-β (ERβ), in the DRG neuron and microglia, but not the dorsal spinal cord, contributed to SNI-induced neuronal sensitisation. Inhibiting GPER expression in the DRG alleviated SNI-induced pain behaviours and neuroinflammation by downregulating iNOS, IL-1β and IL-6 expression as well as restoring GABAα2 expression simultaneously. Additionally, the positive interaction between GPER and β-alanine, β-alanine accumulation enhances pain sensation and promotes chronic pain development. Conclusion: GPER activation in the DRG causes a positive interaction of β-alanine with iNOS, IL-1β and IL-6 expression and represses GABAα2 involved in post-SNI neuropathic pain development. Blocking GPER and eliminating β-alanine in the DRG neuron and microglia may prevent neuropathic pain development.