Myoloid-related protein 8, an endogenous ligand of Toll-like receptor 4, is involved in epileptogenesis of mesial temporal lobe epilepsy via activation of the nuclear factor-κB pathway in astrocytes

Mol Neurobiol. 2014 Feb;49(1):337-51. doi: 10.1007/s12035-013-8522-7. Epub 2013 Aug 28.

Abstract

The role of Toll-like receptor 4 (TLR4) in the activation of innate immunity has been extensively studied in the past several years. Here, we are the first to report that myeloid-related protein 8 (MRP8), an endogenous TLR4 ligand, is involved in the epileptogenesis of mesial temporal lobe epilepsy (MTLE). We find that the expression of MRP8, TLR4, and interleukin 1-β (IL-1β) was upregulated in a MTLE model during both acute and chronic disease stages. We next investigated the possible roles played by astrocytes, which have been shown to be the major source of IL-1β during epilepsy. Stimulation via MRP8 led to the induction of IL-1β in astrocytes in vitro, accompanied by the activation of Nuclear Factor-κB, while knockdown of TLR4 or inhibition of NF-κB in astrocytes prevented this IL-1β induction. Thus, MRP8 may potentiate the perpetuation of MTLE by activating the NF-κB pathway in astrocytes, and could be a new target for anticonvulsant therapies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Astrocytes / metabolism*
  • Astrocytes / pathology
  • Calgranulin A / biosynthesis*
  • Cells, Cultured
  • Child
  • Epilepsy, Temporal Lobe / metabolism*
  • Epilepsy, Temporal Lobe / pathology
  • Female
  • Humans
  • Ligands
  • Male
  • NF-kappa B / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction / physiology*
  • Toll-Like Receptor 4 / biosynthesis*

Substances

  • Calgranulin A
  • Ligands
  • NF-kappa B
  • Tlr4 protein, rat
  • Toll-Like Receptor 4