Figure 5

MAPKs regulated CD38 expression and function in IL-1β-activated astrocytes. Following 1 hour pre-treatment with various MAPK inhibitors, primary astrocytes were activated with IL-1β, 20 ng/ml. Untreated controls were maintained in parallel. CD38 mRNA levels were measured using real-time PCR while CD38 activity, as a measure of CD38 function, was analyzed using cADPR cyclase assay. As expected, IL-1β alone significantly increased CD38 expression and activity as compared to untreated controls (p < 0.001, all panels). Basal CD38 expression was unchanged (p > 0.05, A-C) by inhibitor pre-treatment. The IL-1β-induced increase in CD38 mRNA expression was abrogated by pre-treatment with inhibitors specific to (A) p38, SB203580 (p < 0.001) (B) JNK, SP600125 (p < 0.001) and (C) ERK, U0126 (p < 0.001). (D) Pre-treatment with each of the MAPK inhibitors significantly inhibited the IL-1β-mediated CD38 cADPR cyclase activity in astrocytes (p < 0.001).