IL-34 Upregulated Th17 Production through Increased IL-6 Expression by Rheumatoid Fibroblast-Like Synoviocytes

Figure 3

IL-34 dramatically promoted IL-6 production of FLS through JNK/P38/NF-κB signaling pathway. (a) RA FLS () were pretreated with or without inhibitors of signaling molecules for 1 h and then stimulated by IL-34 (50 ng/ml) for 30 min. Protein was acquired in whole cell lysis buffer (20 μg/lane); meanwhile, phosphorylations of P38, NF-κB, ERK1/2, and JNK were analyzed by Western blotting using anti-phospho-specific antibody. Total P38, NF-κB, ERK1/2, and JNK (20 μg/lane) were determined by Western blotting using corresponding antibodies, respectively. The expression ratios of p-P38 to P38, p-NF-κB to NF-κB, p-ERK1/2 to ERK1/2, and p-JNK to JNK were represented in a bar graph. Data represents the mean ± SEM. , , ns: no significant compared with the untreated cells. (b) FLS isolated from RA patients () were pretreated with inhibitors of signaling molecules for 1 h or pretreated with anti-CSF-1R mAb (25 ng/ml) for 30 min, respectively, and then incubated with IL-34 (50 ng/ml) for 24 h. The expression of IL-6 mRNA was detected by RT-PCR. Data represents the mean ± SEM. , ns: no significant compared to the group incubated with IL-34 only. (c) FLS isolated from RA patients () were pretreated with inhibitors of signaling molecules for 1 h and then incubated with IL-34 (50 ng/ml) for 72 h. IL-6 levels in the supernatants were measured by ELISA. Data represents the mean ± SEM. Statistical analysis was using the paired t-test. , , ns: no significant compared with the IL-34 group.

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