Figure 2.

Members of the IL-10 family of cytokines are produced by glia in response to central nervous system (CNS) insult, either directly or in a delayed indirect manner, to exacerbate or limit neuroinflammation. Glial cells, including microglia (Mg) and astrocytes (Ast), respond to insult via pattern recognition receptors (PRRs), including cell surface and cytosolic receptors. Following activation, glia release pro-inflammatory cytokines, including IL-6, tumor necrosis factor-α (TNF-α), IL-20 and perhaps IL-22. These mediators act to promote the clearance of the initial insult by altering the integrity of the blood brain barrier (BBB) and recruiting leukocytes from the circulation. In addition, inflammatory mediators act in an autocrine and/or paracrine manner to promote the delayed expression of IL-10, IL-19 and IL-24 by glia. These cytokines act via their cognate receptors expressed by astrocytes and microglia, and perhaps oligodendrocytes (OD) and neurons (Neu), to curtail the inflammatory responses of these cells and/or recruited leukocytes.