ATP Is Required and Advances Cytokine-Induced Gap Junction Formation in Microglia In Vitro

Figure 8

Cytokine-induced activation and the effect on gap junctional communication and HCs activity in cultured microglia. (1) Under resting condition, microglia express P2X receptors, Cx43, and Panx1, which have a low activity. Furthermore, no gap junction channel (GJC) communication is observed. (2) After TNF-α plus ATP exposition activated microglia exhibit gap junctional communication, but not intercellular communication mediated by hemichannels (HCs). (3) However, treatment with TNF-α/IFN-γ increased both GJC and HC functional state. (4) Extracellular ATP increases the Panx1 HC activity in both, resting or TNF-α/IFN-γ-activated microglia. (5) IL-1β release from activated microglia favors gap junctional communication. (6) IL-6 prevents IL-1β release and the increase in GJC and HC functional state.