TLR2 mediates neuroinflammation and neuronal damage

Olaf Hoffmann, Johann S. Braun, Doreen Becker, Annett Halle, Dorette Freyer, Emilie Dagand, Seija Lehnardt, Joerg R. Weber

Research output: Contribution to journalArticlepeer-review

112 Citations (Scopus)

Abstract

Innate immunity relies on pattern recognition receptors to detect the presence of infectious pathogens. In the case of Gram-positive bacteria, binding of bacterial lipopeptides to TLR2 is currently regarded as an important mechanism. In the present study, we used the synthetic bacterial lipopeptide Pam3CysSK4, a selective TLR2 agonist, to induce meningeal inflammation in rodents. In a 6-h rat model, intrathecal application of Pam 3CysSK4 caused influx of leukocytes into the cerebrospinal fluid (CSF) and induced a marked increase of regional cerebral blood flow and intracranial pressure. In wild-type mice, we observed CSF pleocytosis and an increased number of apoptotic neurons in the dentate gyrus 24 h after intrathecal challenge. Inflammation and associated neuronal loss were absent in TLR2 knockout mice. In purified neurons, cytotoxicity of Pam 3CysSK4 itself was not observed. Exposure of microglia to Pam3CysSK4 induced neurotoxic properties in the supernatant of wild-type, but not TLR2-deficient microglia. We conclude that TLR2-mediated signaling is sufficient to induce the host-dependent key features of acute bacterial meningitis. Therefore, synthetic lipopeptides are a highly specific tool to study mechanisms of TLR2-driven neurodegeneration in vivo.

Original languageEnglish
Pages (from-to)6476-6481
Number of pages6
JournalJournal of Immunology
Volume178
Issue number10
DOIs
Publication statusPublished - May 15 2007

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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