Transforming growth factor-beta inhibits interleukin-10 synthesis by human monocytic cells.
Transforming growth factor-beta (TGF-beta1) enhances interleukin-10 (IL-10) synthesis by mouse monocytes/macrophages, suggesting a potential role of IL-10 in mediating some of the anti-inflammatory properties of TGF-beta1. Since differences exist between the transcriptional regulation of human and mouse IL-10, the studies reported here examined whether TGF-beta1 up-regulated IL-10 production by human monocytes/macrophages as well. Exposure of PMA-differentiated U-937 promonocytic cells to TGF-beta1 resulted in an unexpected, dose-dependent decrease in IL-10 production as assessed by specific ELISA. TGF-beta1 was effective when added at the time of the PMA stimulus or 6 hours after. In addition, TGF-beta1 suppressed induction of IL-10 by three different stimuli other than PMA. TGF-beta1 inhibition of IL-10 protein release was associated with proportional changes in IL-10 mRNA accumulation as assessed by quantitative kinetic ELISA PCR. This would result from a decrease in IL-10 gene transcription as TGF-beta1 did not affect IL-10 mRNA stability, and TGF-beta1 limited the luciferase activity in cells transfected with reporter gene constructs containing 1,308 bp of the 5' non-coding sequence of human IL-10 gene. Blocking tumour necrosis factor-alpha (TNF-alpha) with neutralizing anti-TNF-alpha antibody did not modify the response to TGF-beta1, indicating the involvement of TNF-alpha-independent mechanisms in the overall process. Thus, the present study provides the first evidence that TGF-beta1 prevents IL-10 production by human monocytic cells at a transcriptional level.
Suberville
S
S
Service d'Explorations Fonctionnelles Multidisciplinaires, Hôpital Tenon, 4, rue de la Chine, 75020 Paris, France.
Bellocq
A
A
Peguillet
I
I
Lantz
O
O
Stordeur
P
P
Fouqueray
B
B
Baud
L
L
D002454:Cell Differentiation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D017930:Genes, Reporter; D006801:Humans; D016753:Interleukin-10 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000502:physiology*; D020298:U937 Cells
D016212:Transforming Growth Factor beta; D016753:Interleukin-10; D013755:Tetradecanoylphorbol Acetate