Introduction: The mechanism of cell activation by LPS in the absence of surface Toll-like receptor 4 (TLR4) is unclear. We hypothesize that ICAM-1 binds LPS on the cell surface, mediating cell activation independent of TLR4.
Methods: The interaction between murine ICAM-1 and LPS was measured in a binding assay. Alveolar macrophages (AMs) isolated from TLR4 deficient mice were stimulated with LPS. Cell activation was measured by flow cytometry and cytokine production. The role of ICAM-1 in cell activation was determined by siRNA transfection.
Results: Murine ICAM-1 binds LPS. TLR4 deficient AMs respond to LPS stimulation by upregulation of LPS binding sites, ICAM-1 expression and cytokine release. Cell activation is attenuated by treatment with polymyxin B and ICAM-1 gene silencing.
Conclusions: ICAM-1 binds LPS and is important in TLR4-independent cell activation. Strategies devised to target ICAM-1 may have the potential to block the excessive inflammatory response seen in gram-negative sepsis.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/17702 |
| Date | 22 September 2009 |
| Creators | Pabari, Reena |
| Contributors | Zhang, Haibo |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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