Systematic analysis of critical genes and pathways identified a signature of neuropathic pain after spinal cord injury

Eur J Neurosci. 2022 Jul;56(2):3991-4008. doi: 10.1111/ejn.15693. Epub 2022 May 27.

Abstract

Spinal cord injury (SCI) damages sensory systems, producing chronic neuropathic pain that is resistant to medical treatment. The specific mechanisms underlying SCI-induced neuropathic pain (SCI-NP) remain unclear, and protein biomarkers have not yet been integrated into diagnostic screening. To better understand the host molecular pathways involved in SCI-NP, we used the bioinformatics method, the PubMed database and bioinformatics methods to identify target genes and their associated pathways. We reviewed 2504 articles on the regulation of SCI-NP and used the text mining of PubMed database abstracts to determine associations among 12 pathways and networks. Based on this method, we identified two central genes in SCI-NP: interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α). Adult male Sprague-Dawley rats were used to build the SCI-NP models. The threshold for paw withdrawal was significantly reduced in the SCI group, and TLR4 was activated in microglia after SCI. Enzyme-linked immunosorbent assay(ELISA) analysis of TNF-α and IL-6 levels was significantly higher in the SCI group than in the sham group. Western blot showed that expressions of the TLR4/MyD88/NF-κB inflammatory pathway protein increased dramatically in the SCI group. Using the TLR4 inhibitor TAK-242, the pain threshold and expressions of inflammatory factors and proteins of the proteins of the inflammatory signal pathway were reversed, TLR4 in microglia was suppressed, suggesting that SCI-NP was related to neuroinflammation mediated by the TLR4 signalling pathway. In conclusion, we found that TNF-α and IL-6 were the neuroinflammation-related genes involved in SCI-NP that can be alleviated by inhibiting the inflammatory pathway upstream of the TLR4/MyD88/NF-κB inflammatory pathway.

Keywords: natural language processing analysis; neuroinflammation; neuropathic pain; spinal cord injury; toll-like receptor 4.

Publication types

  • Review
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Interleukin-6 / genetics
  • Interleukin-6 / metabolism
  • Male
  • Myeloid Differentiation Factor 88 / metabolism
  • NF-kappa B / metabolism
  • Neuralgia* / genetics
  • Neuralgia* / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Spinal Cord / metabolism
  • Spinal Cord Injuries* / complications
  • Spinal Cord Injuries* / genetics
  • Spinal Cord Injuries* / metabolism
  • Toll-Like Receptor 4 / genetics
  • Toll-Like Receptor 4 / metabolism
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • Interleukin-6
  • Myeloid Differentiation Factor 88
  • NF-kappa B
  • Toll-Like Receptor 4
  • Tumor Necrosis Factor-alpha