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Interleukin 4 or oncostatin M induces a prolonged increase in P-selectin mRNA and protein in human endothelial cells
1W.K. Warren Medical Research Institute, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, USA.
Abstract:
During acute inflammation, P-selectin is transiently mobilized from Weibel-Palade bodies to the surface of histamine-activated endothelial cells, where it mediates rolling adhesion of neutrophils under hydrodynamic flow. During chronic or allergic inflammation, sustained expression of P-selectin on the endothelial cell surface has been observed. We found that the cytokines interleukin 4 (IL-4) or oncostatin M (OSM) induced a five- to ninefold increase in P-selectin messenger RNA (mRNA) in human umbilical vein endothelial cells (HUVEC) that persisted as long as 72 h. IL-4 elevated P-selectin mRNA by increasing its transcription rate rather than by prolonging its already long half-life. Stimulation of P-selectin transcription by IL-4 or OSM required new protein synthesis and tyrosine phosphorylation of cellular proteins. Tumor necrosis factor alpha, IL-1 beta, lipopolysaccharide, or IL-3 did not increase P-selectin mRNA in HUVEC, and did not augment the IL-4-induced increase in P-selectin transcripts. IL-4 or OSM increased P-selectin protein on the cell surface as well as in Weibel-Palade bodies. Under flow conditions, neutrophils rolled on P-selectin expressed by IL-4-treated HUVEC, and even more neutrophils rolled on P-selectin after IL-4-treated HUVEC were stimulated with histamine. These data demonstrate that IL-4 or OSM stimulates endothelial cells to synthesize more P-selectin over prolonged periods. The increased expression of P-selectin may facilitate the emigration of leukocytes into sites of chronic or allergic inflammation.
Insights
Interleukin-4 (IL-4) and oncostatin M (OSM) cytokines increase P-selectin messenger RNA (mRNA) and protein in endothelial cells. This sustained P-selectin expression may promote leukocyte migration in chronic inflammation.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- P-selectin mediates neutrophil adhesion to endothelial cells during acute inflammation.
- Sustained P-selectin expression is observed in chronic or allergic inflammatory conditions.
Purpose of the Study:
- To investigate the effects of cytokines IL-4 and OSM on P-selectin expression in human umbilical vein endothelial cells (HUVEC).
- To determine the molecular mechanisms underlying IL-4-induced P-selectin gene expression.
Main Methods:
- HUVEC were treated with IL-4 or OSM, and P-selectin mRNA levels were quantified using Northern blot analysis.
- P-selectin transcription rates were assessed by measuring mRNA accumulation.
- Protein synthesis and tyrosine phosphorylation were evaluated.
- Neutrophil rolling adhesion assays were performed under flow conditions.
Main Results:
- IL-4 and OSM induced a significant and sustained increase in P-selectin mRNA in HUVEC for up to 72 hours.
- IL-4 increased P-selectin mRNA by enhancing transcription, not by altering mRNA stability.
- Stimulation of P-selectin transcription by IL-4 or OSM required de novo protein synthesis and tyrosine phosphorylation.
- IL-4 or OSM increased cell surface and Weibel-Palade body P-selectin protein levels.
- Neutrophils exhibited rolling adhesion on IL-4-treated HUVEC, which was further enhanced by histamine stimulation.
Conclusions:
- IL-4 and OSM induce prolonged synthesis of P-selectin in endothelial cells.
- This sustained upregulation of P-selectin may contribute to leukocyte recruitment in chronic and allergic inflammatory diseases.