title: Airborne allergens induce protease activated receptor-2-mediated production of inflammatory cytokines in human gingival epithelium.
abstract: OBJECTIVE
  In reaching the airways inhaled allergens pass through and contact with the oral mucosa. Although they are often responsible for initiating asthmatic attacks, it is unknown whether airborne allergens can also trigger chronic inflammation of gingival epithelial cells leading to chronic periodontitis. In this study, we investigated the inflammatory responses of human gingival epithelial cells (HGECs) to airborne allergens, particularly German cockroach extract (GCE) with a focus on calcium signaling.
  
  
  METHODS
  HGECs isolated from healthy donors were stimulated with GCE. Intracellular Ca(2+) concentration ([Ca(2+)]i) was measured with Fura-2-acetoxymethyl ester (Fura-2/AM) staining. Expression of inflammatory cytokines interleukin (IL)-8, IL-1β, IL-6, and NOD-like receptor family, pyridine domain-containing (NLRP) 3 was analyzed using reverse transcription-polymerase chain reaction (RT-PCR).
  
  
  RESULTS
  GCE promoted increase in the [Ca(2+)]i in a dose-dependent manner. Depletion of endoplasmic reticulum (ER) Ca(2+) by the ER Ca(2+) ATPase inhibitor thapsigargin (Tg) but not the depletion of extracellular Ca(2+) abolished the GCE-induced increase in [Ca(2+)]i. Treatment of phospholipase C (PLC) inhibitor (U73122) or 1,4,5-trisinositolphosphate (IP3) receptor inhibitor (2-APB) also prevented GCE-induced increase in [Ca(2+)]i. Protease activated receptor (PAR)-2 activation mainly mediated the GCE-induced increase in [Ca(2+)]i and enhanced the expression of IL-8, NLRP3, IL-1β, and IL-6 in HGECs.
  
  
  CONCLUSIONS
  GCE activates PAR-2, which can induce PLC/IP3-dependent Ca(2+) signaling pathway, ultimately triggering inflammation via the production of pro-inflammatory cytokines such as IL-1β, IL-6, IL-8, and NLRP 3 in HGECs.
authors.affiliation: Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea; BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Republic of Korea.
authors.forename: Ga-Yeon
authors.initials: GY
authors.lastname: Son
authors.affiliation: Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea.
authors.forename: Aran
authors.initials: A
authors.lastname: Son
authors.affiliation: Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea.
authors.forename: Yu-Mi
authors.initials: YM
authors.lastname: Yang
authors.affiliation: Department of Advanced General Dentistry, Yonsei University College of Dentistry, Seoul, Republic of Korea.
authors.forename: Wonse
authors.initials: W
authors.lastname: Park
authors.affiliation: Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea.
authors.forename: Inik
authors.initials: I
authors.lastname: Chang
authors.affiliation: Department of Pediatric Dentistry, Yonsei University College of Dentistry, Seoul, Republic of Korea.
authors.forename: Jae-Ho
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea; BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Republic of Korea. Electronic address: dmshin@yuhs.ac.
authors.forename: Dong Min
authors.initials: DM
authors.lastname: Shin
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology*; D000818:Animals; D001896:Boron Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D003058:Cockroaches / Q000276:immunology*; D016207:Cytokines / Q000378:metabolism*; D004847:Epithelial Cells / Q000276:immunology*; D004963:Estrenes / Q000494:pharmacology; D005260:Female; D016257:Fura-2; D005881:Gingiva / Q000166:cytology / Q000276:immunology*; D006801:Humans; D019570:Inhalation Exposure; D008297:Male; D011760:Pyrrolidinones / Q000494:pharmacology; D044464:Receptor, PAR-2 / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019284:Thapsigargin / Q000494:pharmacology
chemical_list: D000485:Allergens; D001896:Boron Compounds; D016207:Cytokines; D004963:Estrenes; D011760:Pyrrolidinones; D044464:Receptor, PAR-2; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D019284:Thapsigargin; C109986:2-aminoethoxydiphenyl borate; D002118:Calcium; D016257:Fura-2
keywords: Allergens; Calcium; Gingival epithelial cells; Inflammation; PAR-2