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Updated: Jun 7, 2026
A Macrophage Reporter Cell Assay to Examine Toll-Like Receptor-Mediated NF-kB/AP-1 Signaling on Adsorbed Protein Layers on Polymeric Surfaces
Published on: January 7, 2020
[Involvement of Toll-like receptor in silica-induced tumor necrosis factor alpha release from human macrophage cell
1College of Public Health, Zhengzhou University, Zhengzhou 450001, China.
Objective:
To characterize the role of Toll-like receptor 4 (TLR4) in silica-induced production of tumor necrosis factor alpha (TNFalpha) from macrophage cell line.
Methods:
The human macrophage cell line THP-1 was incubated with silica suspension. Cell media were collected and TNFalpha levels in the supernatants measured with ELISA. To examine the involvement of TLR4 in silica-induced TNFalpha release, the neutralizing antibody (HTA125) against human TLR4 receptor was employed to pretreat THP-1 cells prior to silica treatment. Moreover, murine macrophages expressing wild type or mutated TLR4 were also treated with silica to verify the effect of TLR4 in silica-induced TNFalpha release.
Results:
Compared with the control group [(3.18 +/- 0.41) pg/ml], the TNFalpha release in cells exposed to 100 microg/ml silica for 4 h and 8 h [(4.71 +/- 0.84), (6.22 +/- 0.58) pg/ml, respectively] increased 1.48 and 1.96 fold, respectively. Pretreatment of THP-1 cells with 20 microg/ml HTA125 antibody significantly blocked silica-induced TNFalpha release by 27%. Furthermore, the TNFalpha content released from cells expressing mutated TLR4 reduced by 30% in compared with that from the cells expressing wild type TLR4 after silica stimulation.
Conclusion:
TLR4 mediates silica-induced TNFalpha release from macrophages.
Insights
Toll-like receptor 4 (TLR4) mediates silica-induced tumor necrosis factor alpha (TNFalpha) release in macrophages. Blocking TLR4 significantly reduced TNFalpha production, highlighting its critical role in the inflammatory response to silica.
Area of Science:
- Immunology
- Cell Biology
Context:
- Silica exposure can trigger inflammatory responses in macrophages.
- Tumor necrosis factor alpha (TNFalpha) is a key pro-inflammatory cytokine.
- Toll-like receptor 4 (TLR4) is an important pattern recognition receptor involved in innate immunity.
Purpose:
- To investigate the role of Toll-like receptor 4 (TLR4) in silica-induced TNFalpha production by macrophages.
- To determine if blocking TLR4 can inhibit silica-induced TNFalpha release.
Summary:
- Silica exposure significantly increased TNFalpha release from THP-1 macrophage cells.
- Pretreatment with a neutralizing antibody against TLR4 (HTA125) substantially reduced silica-induced TNFalpha release.
- Macrophages expressing mutated TLR4 showed diminished TNFalpha release upon silica stimulation compared to wild-type cells.
Impact:
- This study demonstrates that TLR4 is a critical mediator of silica-induced inflammation.
- Targeting TLR4 may represent a therapeutic strategy to mitigate silica-induced inflammatory conditions.
