Targeting HMGB1-TLR4 signaling by miR-216a-5p elevation alleviates the inflammatory behavioral hypersensitivity

Neurosci Lett. 2021 Aug 10:759:136043. doi: 10.1016/j.neulet.2021.136043. Epub 2021 Jun 10.

Abstract

Neuroinflammation induced by microglial activation has a critical role in inflammatory pain. In this study, we detected the function of miR-216a-5p in the progression of inflammatory behavioral hypersensitivity. Here, decreases of miR-216a-5p and up-regulation of high-mobility group box1 (HMGB1) were observed in complete freund's adjuvant (CFA)-induced inflammatory pain model in mice and LSP-activated BV2 microglia. HMGB1 was identified as a target of miR-216a-5p by luciferase reporter system. Ectopic expression of miR-216a-5p suppressed microglial marker IBA-1 expression and subsequent pro-inflammatory cytokine releases (IL-1β, IL-6 and TNF-α) from LPS-activated microglia. Additionally, LPS exposure enhanced the protein expression levels of HMGB1, TLR4 and p-p65 NF-kB in microglia, which were abrogated following miR-216a-5p overexpression. Intriguingly, transfection of HMGN1 cDNA into BV2 microglial cells reversed the inhibitory effects of miR-216a-5p elevation on microglial activation-triggered inflammatory response. Intrathecal delivery of LV-miR-216a-5-p ameliorated CFA-evoked mechanical and thermal hyperalgesia in mice. Concomitantly, overexpressing miR-216a-5p also restrained the inflammatory response and microglia activation in CFA-induced inflammatory mouse models, concomitant with the decreases in the expression of HMGB1, TLR4 and p-p65 NF-kB in spinal cord. Thus, these findings highlight that miR-216a-5p may alleviate inflammatory behavioral hypersensitivity by blocking microglia-mediated neuroinflammation via targeting the HMGB1-TLR4-NF-kB pathway, supporting miR-216a-5p as a potential therapeutic avenue for inflammatory pain.

Keywords: HMGB1; Hyperalgesia; Inflammatory pain; Microglial; TLR4; miR-216a-5p.

MeSH terms

  • Animals
  • Behavior, Animal / physiology
  • HMGB1 Protein / metabolism*
  • Hyperalgesia / metabolism*
  • Inflammation / metabolism*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • MicroRNAs / metabolism*
  • Microglia / metabolism
  • Signal Transduction / physiology
  • Toll-Like Receptor 4 / metabolism*

Substances

  • HMGB1 Protein
  • HMGB1 protein, mouse
  • MIRN216 microRNA, mouse
  • MicroRNAs
  • Tlr4 protein, mouse
  • Toll-Like Receptor 4