Signal pathways mediating TNF-α expression in MTBRa-stimulated human PMCs.

<p>(A), MeT-5A cells were pretreated with vehicle, SP600125 (SP), SB20358 (SB), LY294002 (LY), Parthenolide (Par), PD98059 (PD), respectively, then stimulated with MTBRa (1 ng/ml) for 24 h. TNF-α protein expression was assessed by Western blot. (B), MeT-5A cells were pretreated with PD98059 (PD) (10 μM), followed by stimulation with MTBRa (1 ng/ml) for 4h. TNF-α mRNA concentrations were analyzed by RT-PCR. (C), MeT-5A cells were pretreated with PD98059 (PD) (5 and 10 μM) following stimulation with MTBRa (1 ng/ml) for 6 h, supernatant TNF-α level was analyzed by ELISA. (D), MeT-5A cells were treated with MTBRa (1 ng/ml) for the indicated times. ERK expression was analyzed by Western blotting with antibodies specific for phosphorylated or total proteins. ^##p <0.01, ^###p<0.001 compared with the resting group; **p<0.001, ***p<0.001 compared with the vehicle (DMSO) group. PMC, pleural mesothelial cell; TLR, toll-like receptor; MTBRa, heat-killed <i>M</i>. <i>tuberculosis</i> H37Ra; TNF, tumor necrosis factor; ERK, extracellular-signal-regulated kinase.