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TNF-alpha and IL-1 upregulate membrane-bound and soluble E-selectin through a common pathway
C W Wyble1, K L Hynes, J Kuchibhotla
1Department of Surgery, University of Chicago, MC 5029, 5841 S. Maryland Ave., Chicago, Illinois 60637, USA.
The Journal of Surgical Research
|February 7, 1998
Summary
Soluble E-selectin, released from endothelial cells, can bind neutrophils in the bloodstream, reducing inflammation. This study shows shedding of E-selectin receptors, not new synthesis, is the source of soluble E-selectin.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- E-selectin mediates neutrophil (PMN) capture in microcirculation, initiating inflammation.
- Soluble E-selectin (sE-selectin) can bind circulating PMN, reducing tissue adhesion.
Purpose of the Study:
- Characterize molecular response to cytokines (TNF-alpha, IL-1).
- Investigate the balance between cell surface-bound and soluble E-selectin.
- Determine the source of soluble E-selectin.
Main Methods:
- Cultured human umbilical veins treated with TNF-alpha or IL-1.
- Analyzed E-selectin mRNA (Northern blot), cell surface expression (flow cytometry), and sE-selectin release (ELISA).
- Investigated transcriptional regulation using Raf kinase dominant-negative transfection.
Main Results:
- Cytokines induced E-selectin mRNA and cell surface expression, peaking at 6h.
- Soluble E-selectin levels increased later, starting at 12h and continuing to 24h.
- Raf kinase inhibition reduced both surface and soluble E-selectin expression.
Conclusions:
- Late increases in sE-selectin accompanied by decreases in cell surface E-selectin indicate shedding of receptors.
- The primary source of circulating E-selectin is shed receptors, not new synthesis.
- Enhancing E-selectin shedding may offer therapeutic benefits by reducing PMN adhesion.