Staphylococcus aureus-derived peptidoglycan induces Cx43 expression and functional gap junction intercellular communication in microglia

Sarita Garg, Mohsin Md Syed, Tammy Kielian

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


Gap junctions serve as intercellular conduits that allow the exchange of small molecular weight molecules (up to 1 kDa) including ions, metabolic precursors and second messengers. Microglia are capable of recognizing peptidoglycan (PGN) derived from the outer cell wall of Staphylococcus aureus, a prevalent CNS pathogen, and respond with the robust elaboration of numerous pro-inflammatory mediators. Based on recent reports demonstrating the ability of tumor necrosis factor-α and interferon-γ to induce gap junction coupling in macrophages and microglia, it is possible that pro-inflammatory mediators released from PGN-activated microglia are capable of inducing microglial gap junction communication. In this study, we examined the effects of S. aureus-derived PGN on Cx43, the major connexin in microglial gap junction channels, and functional gap junction communication using single-cell microinjections of Lucifer yellow (LY). Exposure of primary mouse microglia to PGN led to a significant increase in Cx43 mRNA and protein expression. LY microinjection studies revealed that PGN-treated microglia were functionally coupled via gap junctions, the specificity of which was confirmed by the reversal of activation-induced dye coupling by the gap junction blocker 18-α-glycyrrhetinic acid. In contrast to PGN-activated microglia, unstimulated cells consistently failed to exhibit LY dye coupling. These results indicate that PGN stimulation can induce the formation of a functional microglial syncytium, suggesting that these cells may be capable of influencing neuroinflammatory responses in the context of CNS bacterial infections through gap junction intercellular communication.

Original languageEnglish (US)
Pages (from-to)475-483
Number of pages9
JournalJournal of Neurochemistry
Issue number2
StatePublished - Oct 2005
Externally publishedYes


  • Central nervous system
  • Connexin 43
  • Gap junction
  • Microglia
  • Neuroinflammation
  • Peptidoglycan

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience


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