Chitinase activates protease-activated receptor-2 in human airway epithelial cells

Hee Hong Jeong, Yeon Hong Jung, Boryung Park, Syng Ill Lee, Taeg Seo Jeong, Kyu Earn Kim, Hyun Sohn Myung, Min Shin Dong

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)

Abstract

Mammalian chitinase released by airway epithelia is thought to be an important mediator of disease manifestation in an experimental model of asthma. However, the intracellular signaling mechanisms engaged by exogenous chitinase in human airway epithelial cells are unknown. Here, we investigated the direct effects of exogenous chitinase from Streptomyces griseus on Ca2+ signaling in human airway epithelial cells. Spectrofluorometry was used to measure intracellular Ca2+ concentration ([Ca2+] i) in fura-2-AM-loaded cells. S. griseus chitinase induced dose-dependent [Ca2+]i increases in normal human bronchial epithelial cells and promoted [Ca2+]i oscillations in H292 cells. Chitinase-induced [Ca2+]i oscillations were independent of extracellular Ca2+, suggesting that the observed [Ca2+]i increases were due to Ca2+ release from intracellular stores. Accordingly, after depleting endoplasmic reticulum (ER) Ca2+ with the ER Ca2+ ATPase inhibitor, thapsigargin, chitinase-mediated [Ca2+]i increases were abolished. Treatment with the phospholipase C (PLC) inhibitor U73122 or the 1, 4, 5-trisinositolphosphate (IP3) receptor inhibitor 2-APB attenuated chitinase-induced [Ca2+]i increases. Desensitization of protease-activated receptor-2 (PAR-2) by repetitive agonist stimulation or siRNA-mediated PAR-2 knockdown revealed that chitinase-mediated [Ca 2+]i increases were exclusively mediated by PAR-2 activation. Finally, chitinase was found to cleave a model peptide representing the cleavage site of PAR-2 and enhanced IL-8 production. These results indicate that exogenous chitinase is a potent proteolytic activator of PAR-2 that can directly induce PLC/IP3-dependent Ca2+ signaling in human airway epithelial cells.

Original languageEnglish
Pages (from-to)530-535
Number of pages6
JournalAmerican Journal of Respiratory Cell and Molecular Biology
Volume39
Issue number5
DOIs
Publication statusPublished - 2008 Nov 1

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Pulmonary and Respiratory Medicine
  • Clinical Biochemistry
  • Cell Biology

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