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Inflammatory agonists induce cyclooxygenase type 2 expression by human neutrophils
C G Maloney1, W A Kutchera, K H Albertine
1The Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah School of Medicine, Salt Lake City 84112, USA.
Journal of Immunology (Baltimore, Md. : 1950)
|May 7, 1998
Summary
Human polymorphonuclear leukocytes (PMNs) express cyclooxygenase-2 (COX-2) when stimulated by inflammatory signals like LPS. This COX-2 expression in PMNs contributes to the inflammatory process by producing PGE2.
Area of Science:
- Biochemistry
- Immunology
- Molecular Biology
Background:
- Prostanoid synthesis is regulated by cyclooxygenases (prostaglandin H synthases), crucial targets for anti-inflammatory drugs.
- Cyclooxygenase-2 (COX-2) is an inducible isoform involved in inflammation.
Purpose of the Study:
- To investigate COX-2 expression in human polymorphonuclear leukocytes (PMNs) upon stimulation.
- To determine the role of COX-2 in PMN-mediated inflammatory responses and prostanoid production.
Main Methods:
- Immunohistochemical analysis of COX-2 expression in PMNs.
- Stimulation of isolated human PMNs with lipopolysaccharide (LPS), TNF-alpha, IL-1, and IL-8.
- Measurement of prostaglandin E2 (PGE2) secretion and inhibition studies using selective COX-2 inhibitors and dexamethasone.
Main Results:
- Human PMNs express COX-2 upon stimulation with LPS, TNF-alpha, IL-1, and IL-8, but not in freshly isolated cells.
- COX-2 expression in PMNs is time- and concentration-dependent and parallels PGE2 secretion.
- COX-2 expression and regulation differ between PMNs, monocytes, and macrophages, indicating lineage-specific control.
Conclusions:
- PMNs express inducible COX-2 when activated by inflammatory stimuli.
- Activated PMNs can actively contribute to the inflammatory milieu through COX-2-mediated PGE2 production.
- Differential regulation of COX-2 in myeloid cells highlights distinct roles in inflammatory responses.