Human bronchial epithelial cells express PAR-2 with different sensitivity to thermolysin.
Protease-activated receptor-2 (PAR-2) plays a role in inflammatory reactions in airway physiology. Proteases cleaving the extracellular NH(2) terminus of receptors activate or inactivate PAR, thus possessing a therapeutic potential. Using RT-PCR and immunocytochemistry, we show PAR-2 in human airway epithelial cell lines human bronchial epithelial (HBE) and A549. Functional expression of PAR-2 was confirmed by Ca(2+) imaging studies using the receptor agonist protease trypsin. The effect was abolished by soybean trypsin inhibitor and mimicked by the specific PAR-2 peptide agonist SLIGKV. Amplitude and duration of PAR-2-elicited Ca(2+) response in HBE and A549 cells depend on concentration and time of agonist superfusion. The response is partially pertussis toxin (PTX) insensitive, abolished by the phospholipase C inhibitor U-73122, and diminished by the inositol 1,4,5-trisphosphate receptor antagonist 2-aminoethoxydiphenyl borate. Cathepsin G altered neither the resting Ca(2+) level nor PAR-2-elicited Ca(2+) response. Thermolysin, a prototypic bacterial metalloprotease, induced a dose-dependent Ca(2+) response in HBE, but not A549, cells. In both cell lines, thermolysin abolished the response to a subsequent trypsin challenge but not to SLIGKV. Thus different epithelial cell types express different PAR-2 with identical responses to physiological stimuli (trypsin, SLIGKV) but different sensitivity to modifying proteases, such as thermolysin.
Ubl
Joachim J
JJ
Institut für Neurobiochemie, 39120 Magdeburg, Germany.
Grishina
Zoryana V
ZV
Sukhomlin
Tatiana K
TK
Welte
Tobias
T
Sedehizade
Fariba
F
Reiser
Georg
G
D001980:Bronchi / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D053496:Inositol 1,4,5-Trisphosphate Receptors; D009842:Oligopeptides / Q000494:pharmacology; D037342:Pertussis Toxin; D044464:Receptor, PAR-2; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors; D018179:Receptors, Thrombin / Q000187:drug effects / Q000378:metabolism*; D020545:Respiratory Mucosa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013820:Thermolysin / Q000378:metabolism* / Q000494:pharmacology; D014357:Trypsin / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D015220:Calcium Channels; D004791:Enzyme Inhibitors; C506926:ITPR1 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D009842:Oligopeptides; D044464:Receptor, PAR-2; D018160:Receptors, Cytoplasmic and Nuclear; D018179:Receptors, Thrombin; D014361:Trypsin Inhibitors; D010566:Virulence Factors, Bordetella; C109968:seryl-leucyl-isoleucyl--glycyl-lysyl-valine; D037342:Pertussis Toxin; D014357:Trypsin; D013820:Thermolysin; D002118:Calcium