Human airway trypsin-like protease stimulates human bronchial fibroblast proliferation in a protease-activated receptor-2-dependent pathway.
Human airway trypsin-like protease (HAT) was isolated from airway secretions and localized to bronchial epithelial cells by immunohistochemistry. In the present study, we examined whether HAT could stimulate DNA synthesis and proliferation of primary human bronchial fibroblasts (HBF). HAT significantly stimulated the proliferation of HBF by 20-55%, a level similar to that of the mitogenic activity of lung mast cell tryptase (MCT). HAT also stimulated the incorporation of [3H]thymidine in HBF, and this HAT-induced DNA synthesis was abolished by leupeptin. Protease-activated receptor-2 (PAR-2) mRNA was expressed and localized to the cell surface in HBF. PAR-2 activating peptide (AP) also enhanced DNA synthesis, and both HAT and PAR-2 AP induced receptor internalization, similar to the response to trypsin. Pretreatment of HBF with anti-PAR-2 antibody significantly suppressed both HAT and PAR-2 AP-induced DNA synthesis. In addition, HAT and PAR-2 AP induced intracellular Ca2+ mobilization in HBF. The HAT-induced increase in Ca2+ was desensitized by pretreatment with trypsin or PAR-2 AP. U0126, a specific MAPK inhibitor, completely inhibited HAT-induced DNA synthesis as well as HAT-induced phosphorylation of MAPK. The effect of HAT and MCT together was additive, whereas the effect of HAT and insulin together on HBF DNA synthesis was synergistic. These results indicate that HAT stimulates fibroblast proliferation in bronchial airways through a PAR-2-dependent MEK-MAPK mediated pathway and that HAT is linked to airway processes involving fibroblasts.
Matsushima
Rie
R
Dept. of Nutrition and Metabolism, Graduate School of Nutrition and Bioscience, Univ. of Tokushima, 3-18-15 Kuramoto-cho, Tokushima, Japan 770-8503. rie@nutr.med.tokushima-u.ac.jp
Takahashi
Akira
A
Nakaya
Yutaka
Y
Maezawa
Hiroshi
H
Miki
Mari
M
Nakamura
Yoichi
Y
Ohgushi
Fumitaka
F
Yasuoka
Susumu
S
D000368:Aged; D001980:Bronchi / Q000166:cytology; D002070:Butadienes / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects*; D002850:Chromatography, Gel; D004247:DNA / Q000096:biosynthesis; D005347:Fibroblasts / Q000166:cytology* / Q000201:enzymology; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D008168:Lung / Q000166:cytology; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D008875:Middle Aged; D009570:Nitriles / Q000494:pharmacology; D044464:Receptor, PAR-2 / Q000096:biosynthesis / Q000276:immunology / Q000502:physiology*; D012697:Serine Endopeptidases / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D013183:Sputum / Q000378:metabolism; D053802:Tryptases
D002070:Butadienes; D007976:Leupeptins; D009570:Nitriles; D044464:Receptor, PAR-2; C113580:U 0126; D004247:DNA; D012697:Serine Endopeptidases; C112256:human airway trypsin-like protease; D053802:Tryptases; C032854:leupeptin; D002118:Calcium