Figure 2.

When inflammation occurs, many inflammatory signals can transport through GJs or HCs to produce a series of inflammatory reactions. For example, leukocytes infiltrate into the inflammatory tissue, releasing ATP via HCs, and then, ATP interacts with purinergic receptors on the cell surface to influence inflammation. Meanwhile, the purinergic receptors of leukocytes also recognize ATP. The following steps automatically appear: ATP affects adjacent cells through GJs and then it releases from cells through HCs, which leads more inflammation cells to the inflammatory tissue. In turn, inflammation may regulate the surface expression of GJs. PAMP and DAMP activate PRR regulating nuclear transcription processes through MAPKs, NF-κB signaling pathways, which further affect transcription in the cell nucleus. This process can influence the expression of GJs and the releasing of chemokines and MMPs.