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Inhibition of tissue factor surface expression in human peripheral blood monocytes exposed to cytokines
M Ernofsson1, T Tenno, A Siegbahn
1Department of Clinical Chemistry, University Hospital, Uppsala, Sweden.
Abstract:
Interleukin (IL)-4, IL-10, IL-13 and transforming growth factor beta (TGF-beta) are known to regulate several monocyte functions, including inhibition of the synthesis of different cytokines. Using quantitative RT-PCR and flow cytometry analysis we investigated the effects of these cytokines on bacterial lipopolysaccharide (LPS)-induced tissue factor (TF) expression in human monocytes. The effects of IL-4 and IL-10 on monocyte chemoattractant protein-1 (MCP-1)-and C-reactive protein (CRP)-induced TF expression were also studied. A direct comparison revealed that IL-4, IL-10 and IL-13 all down-regulated LPS-induced TF expression in a concentration-dependent manner without the need for priming. In contrast, TGF-beta required 4 h of priming to inhibit TF expression induced by LPS. IL-10 was the most powerful inhibitor, causing almost complete inhibition at 5 ng/ml. IL-4 and IL-13 exhibited a significantly lower inhibitory capacity even at concentrations of 100 ng/ml. IL-4 and IL-10 showed similar concentration-dependent inhibition of MCP-1- and CRP-induced TF expression. We also showed that the regulatory effect of the interleukins occurred at the mRNA level. In vivo, these inhibitory cytokines may play an important regulatory role in preventing thrombosis. IL-10, in particular, may be a possible candidate as a TF-preventing drug.
Insights
Interleukin-10 (IL-10) and other cytokines inhibit tissue factor (TF) expression in monocytes, with IL-10 being the most potent. These findings suggest potential therapeutic roles for TF-inhibiting drugs.
Area of Science:
- Immunology
- Molecular Biology
- Hematology
Background:
- Monocytes play a crucial role in immune responses and thrombosis.
- Cytokines like IL-4, IL-10, IL-13, and TGF-beta modulate monocyte functions.
- Tissue factor (TF) expression in monocytes is a key initiator of the coagulation cascade.
Purpose of the Study:
- To investigate the effects of IL-4, IL-10, IL-13, and TGF-beta on lipopolysaccharide (LPS)-induced TF expression in human monocytes.
- To examine the impact of IL-4 and IL-10 on TF expression induced by monocyte chemoattractant protein-1 (MCP-1) and C-reactive protein (CRP).
Main Methods:
- Quantitative RT-PCR to analyze gene expression.
- Flow cytometry to assess protein expression.
- Treatment of human monocytes with various cytokines and inducers (LPS, MCP-1, CRP).
Main Results:
- IL-4, IL-10, and IL-13 significantly down-regulated LPS-induced TF expression in a concentration-dependent manner.
- IL-10 demonstrated the strongest inhibitory effect, nearly complete at 5 ng/ml.
- TGF-beta required a 4-hour priming period to inhibit LPS-induced TF expression.
- IL-4 and IL-10 also inhibited MCP-1- and CRP-induced TF expression.
- The regulatory effects were observed at the mRNA level.
Conclusions:
- IL-4, IL-10, and IL-13 effectively inhibit monocyte TF expression.
- IL-10 is a particularly potent inhibitor of TF expression.
- These cytokines may play a physiological role in preventing thrombosis in vivo.
- IL-10 presents a potential therapeutic candidate for TF-preventing drugs.