Regulation of mucin secretion from human bronchial epithelial cells grown in murine hosted xenografts.
Studies of regulated mucin secretion from goblet cells in primary cultures of human bronchial epithelial (HBE) cells have suffered, generally, from poor signal-to-noise ratios, with reported secretory responses of <100% (less than onefold) relative to baseline. Using, instead, HBE cells grown as xenografts in the backs of nude mice, we found that UTP (100 micro M) stimulated strong mucin secretory responses from isolated, luminally perfused preparations. The peak response (10 min) for 11 control experiments (37 xenografts) was 3.3 +/- 0.05-fold relative to baseline, and the time-integrated response (60 min) was 23.4 +/- 0.5-fold. Because responses to ATP and UTP were approximately equal, an apical membrane P2Y(2)-receptor (R) is suggested. Additionally, ADP activated mucin release from HBE xenografts, whereas UDP and 2-methlythio-ADP did not, a pattern of response inconsistent with known purinoceptors. Hence, either a novel receptor to ADP is suggested or there is significant conversion of ADP to ATP by ecto-adenylate kinase activity. Adenosine and a nitric oxide donor were without effect. Consistent with P2Y(2)-R coupling to phospholipase C, HBE xenografts responded to ionomycin and PMA; however, they were recalcitrant to forskolin and chlorophenylthio-cAMP, and to 8-bromo-cGMP. Hence, human airway goblet cells, like those of other species, appear to be regulated primarily via phospholipase C pathways, activated particularly by apical membrane P2Y(2)-R agonists.
Conway
Jason D
JD
Cystic Fibrosis/Pulmonary Research and Treatment Center and Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, North Carolina 27599-7248, USA. cwdavis@med.unc.edu
Bartolotta
Tracy
T
Abdullah
Lubna H
LH
Davis
C William
CW
D000241:Adenosine / Q000494:pharmacology; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001980:Bronchi / Q000166:cytology / Q000378:metabolism; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism / Q000637:transplantation*; D020397:Goblet Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009077:Mucins / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology; D018048:Receptors, Purinergic P2 / Q000378:metabolism; D058473:Receptors, Purinergic P2Y2; D020545:Respiratory Mucosa / Q000166:cytology* / Q000378:metabolism*; D015290:Second Messenger Systems / Q000502:physiology; D013045:Species Specificity; D014132:Trachea; D014183:Transplantation, Heterologous; D014544:Uridine Triphosphate / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D009077:Mucins; D020030:Nitric Oxide Donors; C546385:P2RY2 protein, human; C546386:P2ry2 protein, mouse; D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2; D014665:Vasodilator Agents; D009569:Nitric Oxide; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000241:Adenosine; D014544:Uridine Triphosphate