Staphylococcus aureus-derived peptidoglycan induces Cx43 expression and functional gap junction intercellular...

Area of Science:

• Neuroscience
• Immunology
• Cell Biology

Background:

• Gap junctions facilitate intercellular communication by allowing the passage of small molecules.
• Microglia, the immune cells of the central nervous system (CNS), recognize Staphylococcus aureus peptidoglycan (PGN) and release pro-inflammatory mediators.
• Pro-inflammatory cytokines like TNF-α and IFN-γ can induce gap junction coupling in immune cells.

Purpose of the Study:

• To investigate the effect of S. aureus-derived PGN on connexin 43 (Cx43) expression in microglia.
• To determine if PGN stimulation induces functional gap junction communication in microglia.
• To explore the role of microglial gap junctions in CNS bacterial infections.

Main Methods:

• Primary mouse microglia were exposed to S. aureus PGN.
• Cx43 mRNA and protein expression levels were measured.
• Functional gap junction communication was assessed using single-cell microinjections of Lucifer yellow (LY).
• The effect of the gap junction blocker 18-alpha-glycyrrhetinic acid was evaluated.

Main Results:

• PGN exposure significantly increased Cx43 mRNA and protein expression in microglia.
• PGN-treated microglia exhibited functional gap junction coupling, confirmed by LY dye transfer.
• Dye coupling was reversed by 18-alpha-glycyrrhetinic acid, confirming specificity.
• Unstimulated microglia did not show LY dye coupling.

Conclusions:

• PGN stimulation induces the formation of a functional microglial syncytium via gap junctions.
• This microglial intercellular communication may play a role in neuro-inflammatory responses to CNS bacterial infections.
• Cx43 is a key mediator of PGN-induced microglial gap junction communication.