Inhibition of HIV-1 Tat-induced expression of IL-6 and IL-8 by inhibitors of p38 mitogen activated-protein kinase (MAPK). (a-f) Astrocytes were pretreated with 10 μM concentration of p38 MAPK inhibitor (SB203580) 1 hour prior to the transfection. (a, b) The expression levels of IL-6 and IL-8 at mRNA were determined by real time RT-PCR at 6 hours post transfection. The values represented are normalized to their mock-transfected controls. (c, d) The protein concentrations of IL-6 and IL-8 were determined in the cell culture supernatants at 48 hours post transfection by multiplex cytokine assay. (e) Astrocytes were either mock-transfected or transfected with HIV-1 Tat plasmid for a duration of 6 hours and p-p38 levels were measured in whole cell extracts. (f) Astrocytes were either mock-transfected or transfected with HIV-1 Tat plasmid for duration of 6 hours and translocation of p65 was measured. A representative Western blot is shown in panels (e) and (f). Each experiment was done at least in triplicate and each bar represents the ± SE of three individual experiments. Statistical analyses was performed by one-way ANOVA and ** denotes P-value of ≤ 0.01.