title: Production of soluble triggering receptor expressed on myeloid cells by lipopolysaccharide-stimulated human neutrophils involves de novo protein synthesis.
abstract: The triggering receptor expressed on myeloid cells (TREM-1) is a recently identified receptor expressed on neutrophils and monocytes. Activation of the receptor induces neutrophils to release the enzyme myeloperoxidase and inflammatory cytokines such as interleukin-8. TREM-1 has an alternatively spliced variant that lacks the transmembrane region, resulting in the receptor being secreted in a soluble form (sTREM-1). Soluble TREM-1 has been detected in plasma during experimental and clinical sepsis and has been advocated as a diagnostic marker of infection for pneumonia and as a prognostic marker for patients with septic shock. We studied TREM-1 surface expression, using flow cytometry, and simultaneously measured sTREM-1 concentrations in culture supernatants of lipopolysaccharide (LPS)-stimulated neutrophils. TREM-1 surface expression was constitutive and was not upregulated upon LPS stimulation. However, sTREM-1 release from neutrophils was significantly upregulated by LPS stimulation (P < 0.0001), an effect that was abrogated by cycloheximide. Soluble TREM-1 is therefore secreted by human neutrophils in response to LPS challenge in a process involving de novo protein synthesis that is not accompanied by an upregulation of the TREM-1 receptor on the surfaces of the cells.
authors.affiliation: Academic Unit of Anaesthesia & Intensive Care, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom. a.mahdy@abdn.ac.uk
authors.forename: Amr M
authors.initials: AM
authors.lastname: Mahdy
authors.forename: Damon A
authors.initials: DA
authors.lastname: Lowes
authors.forename: Helen F
authors.initials: HF
authors.lastname: Galley
authors.forename: Jane E
authors.initials: JE
authors.lastname: Bruce
authors.forename: Nigel R
authors.initials: NR
authors.lastname: Webster
mesh_terms: D000328:Adult; D002469:Cell Separation; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008070:Lipopolysaccharides / Q000276:immunology*; D008297:Male; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D008875:Middle Aged; D018375:Neutrophil Activation / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism; D010865:Pilot Projects; D011971:Receptors, Immunologic / Q000096:biosynthesis*; D012995:Solubility; D000073871:Triggering Receptor Expressed on Myeloid Cells-1
chemical_list: D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; C408842:TREM1 protein, human; D000073871:Triggering Receptor Expressed on Myeloid Cells-1