Signaling pathways involved in increased CXCL8 production in activated human astrocytes.

Proinflammatory cytokines, such as interleukin (IL)-1β and tumor necrosis factor (TNF)-α, stimulate astrocytes in turn activating protein tyrosine phosphatase SHP2. Specific inhibitors are indicated adjacent to target. SHP2 is upstream of p38, which directly or indirectly modulates extracellular signal regulated kinase (ERK) mitogen-activated protein kinases activity, leading to increased expression of CXCL8 protein.