title: Protease-activated receptor 2 mediates human beta-defensin 2 and CC chemokine ligand 20 mRNA expression in response to proteases secreted by Porphyromonas gingivalis.
abstract: The oral pathogen Porphyromonas gingivalis secretes proteases such as Arg-gingipain B (RgpB) that activate protease-activated receptors (PARs). Human beta-defensins (hBDs) and the macrophage inflammatory protein 3alpha/CC chemokine ligand 20 (CCL20) produced by epithelial cells are antimicrobial peptides that provide cytokine function and play an important role in innate immunity. The aim of the present study was to determine whether specific members of the PAR family mediate the expression of these innate immunity markers in gingival epithelial cells (GECs) when exposed to P. gingivalis cell-free culture supernatant or purified RgpB. hBD-2 mRNA in GECs was induced in response to supernatant and purified RgpB from P. gingivalis (P = 0.02 and P = 0.016, respectively). This effect was abrogated by the protease inhibitor tosyl-l-lysine chloromethyl ketone (TLCK) (P < 0.05). In response to P. gingivalis supernatant and to purified RgpB, the hBD-2 mRNA expression was significantly decreased in PAR-2 gene knockdown cells, whereas no change was detected in PAR-1 gene knockdown cells. CCL20 mRNA expression also increased in response to the supernatant of P. gingivalis, and this effect was blocked by the protease inhibitor, TLCK (P = 0.05 and P = 0.024, respectively), and was blocked in PAR-2 gene knockdown cells. Our data indicate that hBD-2 and CCL20 mRNA up-regulation by P. gingivalis supernatant and purified RgpB was mediated via PAR-2, but not via PAR-1, and that proteases play a role in the regulation of innate immune responses in GECs. GECs use PARs to recognize P. gingivalis and mediate cell responses involved in innate immunity.
authors.affiliation: Department of Oral Biology, School of Dentistry, University of Washington, Box 357132, Seattle, WA 98195-7132, USA. hd2@u.washington.edu
authors.forename: Henrik
authors.initials: H
authors.lastname: Dommisch
authors.forename: Whasun O
authors.initials: WO
authors.lastname: Chung
authors.forename: Maryam G
authors.initials: MG
authors.lastname: Rohani
authors.forename: David
authors.initials: D
authors.lastname: Williams
authors.forename: Minnie
authors.initials: M
authors.lastname: Rangarajan
authors.forename: Mike A
authors.initials: MA
authors.lastname: Curtis
authors.forename: Beverly A
authors.initials: BA
authors.lastname: Dale
mesh_terms: D002478:Cells, Cultured; D054418:Chemokine CCL20; D019742:Chemokines, CC / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D004847:Epithelial Cells / Q000201:enzymology / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D005881:Gingiva / Q000166:cytology / Q000201:enzymology / Q000382:microbiology; D006801:Humans; D019402:Macrophage Inflammatory Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism* / Q000502:physiology; D016966:Porphyromonas gingivalis / Q000201:enzymology* / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis*; D044464:Receptor, PAR-2 / Q000502:physiology*; D015854:Up-Regulation / Q000235:genetics; D023083:beta-Defensins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*
chemical_list: C108355:CCL20 protein, human; D054418:Chemokine CCL20; D019742:Chemokines, CC; C106641:DEFB4A protein, human; D019402:Macrophage Inflammatory Proteins; D012333:RNA, Messenger; D044464:Receptor, PAR-2; D023083:beta-Defensins; D010447:Peptide Hydrolases