Lack of TLR4 modifies the miRNAs profile and attenuates inflammatory signaling pathways

PLoS One. 2020 Aug 11;15(8):e0237066. doi: 10.1371/journal.pone.0237066. eCollection 2020.


TLR4 is a member of the toll-like receptors (TLR) immune family, which are activated by lipopolysaccharide, ethanol or damaged tissue, among others, by triggering proinflammatory cytokines release and inflammation. Lack of TLR4 protects against inflammatory processes and neuroinflammation linked with several neuropathologies. By considering that miRNAs are key post-transcriptional regulators of the proteins involved in distinct cellular processes, including inflammation, this study aimed to assess the impact of the miRNAs profile in mice cortices lacking the TLR4 response. Using mice cerebral cortices and next-generation sequencing (NGS), the findings showed that lack of TLR4 significantly reduced the quantity and diversity of the miRNAs expressed in WT mice cortices. The results also revealed a significant down-regulation of the miR-200 family, while cluster miR-99b/let-7e/miR-125a was up-regulated in TLR4-KO vs. WT. The bioinformatics and functional analyses demonstrated that TLR4-KO presented the systematic depletion of many pathways closely related to the immune system response, such as cytokine and interleukin signaling, MAPK and ion Channels routes, MyD88 pathways, NF-κβ and TLR7/8 pathways. Our results provide new insights into the molecular and biological processes associated with the protective effects of TLR-KO against inflammatory damage and neuroinflammation, and reveal the relevance of the TLR4 receptors response in many neuropathologies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cerebral Cortex / metabolism*
  • Cytokines / metabolism
  • Female
  • Gene Expression Regulation / genetics
  • Inflammation / genetics
  • Inflammation / metabolism
  • Lipopolysaccharides
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • MicroRNAs / genetics*
  • Signal Transduction
  • Toll-Like Receptor 4 / genetics*
  • Toll-Like Receptor 4 / metabolism
  • Transcriptome / genetics


  • Cytokines
  • Lipopolysaccharides
  • MicroRNAs
  • Mirn200 microRNA, mouse
  • Mirn99 microRNA, mouse
  • Tlr4 protein, mouse
  • Toll-Like Receptor 4

Grant support

This work has been supported by grants from the Spanish Ministry of Science and Innovation (SAF2015-69187R)/ (URL: And the Institute Carlos III and FEDER funds (RTA-Network, RD16/0017/0004)/ (URL: granted to C.G. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.