title: Secreted hCLCA1 is a signaling molecule that activates airway macrophages.
abstract: The CLCA gene family produces both secreted and membrane-associated proteins that modulate ion-channel function, drive mucus production and have a poorly understood pleiotropic effect on airway inflammation. The primary up-regulated human CLCA ortholog in airway inflammation is hCLCA1. Here we show that this protein can activate airway macrophages, inducing them to express cytokines and to undertake a pivotal role in airway inflammation. In a U-937 airway macrophage-monocyte cell line, conditioned media from HEK 293 cells heterologously expressing hCLCA1 (with or without fetal bovine serum) increased the levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α and IL-8). This effect was independent of the metalloprotease domain of hCLCA1. Primary porcine alveolar macrophages were similarly activated, demonstrating the effect was not cell line dependent. Similarly, immuno-purified hCLCA1 at physiologically relevant concentration of ~100 pg/mL was able to activate macrophages and induce pro-inflammatory response. This cytokine response increased with higher concentration of immuno-purified hCLCA1. These findings demonstrate the ability of hCLCA1 to function as a signaling molecule and activate macrophages, central regulators of airway inflammation.
authors.affiliation: Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: John C H
authors.initials: JC
authors.lastname: Ching
authors.affiliation: Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Liubov
authors.initials: L
authors.lastname: Lobanova
authors.affiliation: Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Loewen
mesh_terms: D000818:Animals; D002417:Cattle; D018118:Chloride Channels / Q000276:immunology / Q000378:metabolism*; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D057809:HEK293 Cells; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008262:Macrophage Activation; D016676:Macrophages, Alveolar / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D017434:Protein Structure, Tertiary; D015398:Signal Transduction; D013552:Swine; D020298:U937 Cells
chemical_list: C492109:CLCA1 protein, human; D018118:Chloride Channels; D016207:Cytokines