Interleukin‐17 enhances tumor necrosis factor α–induced synthesis of interleukins 1, 6, and 8 in skin and synovial fibroblasts: A possible role as a “fine‐tuning …
Y Katz, O Nadiv, Y Beer - … & Rheumatism: Official Journal of the …, 2001 - Wiley Online Library
Y Katz, O Nadiv, Y Beer
Arthritis & Rheumatism: Official Journal of the American College …, 2001•Wiley Online LibraryObjective To compare the singular and combined effects of tumor necrosis factor α (TNFα),
interleukin‐1β (IL‐1β), and IL‐17 on messenger RNA (mRNA) expression, translation, and
secretion of IL‐6, IL‐8, and IL‐1β in fibroblasts. Methods Fibroblasts were stimulated with the
relevant cytokine (s), pulse labeled with 35S‐methionine, and the newly synthesized
proteins were immunoprecipitated and subjected to sodium dodecyl sulfate–polyacrylamide
gel electrophoresis. Gene expression was determined by Northern blot analysis. Secreted …
interleukin‐1β (IL‐1β), and IL‐17 on messenger RNA (mRNA) expression, translation, and
secretion of IL‐6, IL‐8, and IL‐1β in fibroblasts. Methods Fibroblasts were stimulated with the
relevant cytokine (s), pulse labeled with 35S‐methionine, and the newly synthesized
proteins were immunoprecipitated and subjected to sodium dodecyl sulfate–polyacrylamide
gel electrophoresis. Gene expression was determined by Northern blot analysis. Secreted …
Objective
To compare the singular and combined effects of tumor necrosis factor α (TNFα), interleukin‐1β (IL‐1β), and IL‐17 on messenger RNA (mRNA) expression, translation, and secretion of IL‐6, IL‐8, and IL‐1β in fibroblasts.
Methods
Fibroblasts were stimulated with the relevant cytokine(s), pulse labeled with 35S‐methionine, and the newly synthesized proteins were immunoprecipitated and subjected to sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Gene expression was determined by Northern blot analysis. Secreted proteins were detected by enzyme‐linked immunosorbent assay (ELISA).
Results
IL‐17 alone was a weaker stimulator of the transcription, translation, and secretion of other interleukins than was TNFα or IL‐1β. IL‐17 (10 ng/ml) stimulated the expression of IL‐6 mRNA by 1.3‐fold, while TNFα (1 ng/ml) increased it by 3.7‐fold, and IL‐1β (0.1 ng/ml) increased it by >30‐fold. Unlike TNFα and IL‐1β, IL‐17 hardly affected the expression of IL‐8 and IL‐1β mRNA. Translation of IL‐6 was 6.2 times greater with IL‐17, but TNFα and IL‐1β stimulated it 28.9‐ and 174‐fold, respectively. ELISA‐measured secretion of IL‐6 and IL‐8 increased by 6.7 and 5.8 times, respectively, with IL‐17, compared with 52 and 269 times with TNFα stimulation and 1,356 and 1,084 times with IL‐1β stimulation. Yet, when IL‐17 was combined with other cytokines, these activities were stimulated much beyond the sum of the individual effects. The combination of IL‐17 and TNFα induced the expression of IL‐6 or IL‐1β mRNA 7 times more than their additive stimulation, and that of IL‐8 mRNA 3.8 times more. Likewise, the secretion of IL‐6 and IL‐8 was 20 times and 5 times higher, respectively, than expected. This synergism started after 4 hours of combined treatment, and decayed after 24–48 hours regardless of cytokine presence. It could be blocked with anti–IL‐17 but not with anti–IL‐1.
Conclusion
Our findings suggest that the primary role of IL‐17 is to synergize with TNFα and to fine‐tune the inflammation process. Therefore, IL‐17 may be a potential target for therapeutic intervention.
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