Involvement of a Signal Transduction Mechanism in ATP-induced Mucin Release from Cultured Airway Goblet Cells

Abstract

Release of mucins from cultured airway surface epithelial cells can be stimulated by extracellular ATP via a P2-purinergic receptor-mediated mechanism (K. C. Kim and B. C. Lee. 1991. Br. J. Pharmacol. 103:1053-1056). In this report, we studied the mechanism by which extracellular ATP induces the mucin release. We found that: (1) ATP increased both mucin release and generation of inositol phosphates in a dose-dependent fashion, and their dose-effect relationships were almost superimposed; (2) the increases in both mucin release and the phosphatidylinositol phosphate (PI) turnover by extracellular ATP were partially, but almost equally, blocked by the pretreatment with pertussis toxin (42% for mucin release and 44% for PI turnover). We conclude that in cultured airway goblet cells extracellular ATP stimulates mucin release by a signal transduction mechanism, which seems to involve coupling of ATP-activated P2 purinoceptors with phospholipase C, at least in part, via pertussis toxin-sensitive GTP-binding proteins. This may be an important finding in understanding the regulation of mucin release by airway goblet cells, since a number of agents present in the airway could influence this signal transduction pathway and subsequently modulate the mucin secretion.

Nucleotide-induced mucin release from primary hamster tracheal surface epithelial cells involves the P2u purinoceptor

“…Metabolic labelling of PI was performed as described previously [5]. Briefly, confluent HTSE cells (Day 5) in 24 well plates were incubated for 24 h in the serumfree "complete" Medium 199 (0.2 mL·well -1 ) containing 5 µCi·mL -1 myo-[2-3 H]inositol (Amersham; 80-120 Ci·mmol -1 ).…”

“…At the end of the 30 min period, the spent media were removed and then collagen gels containing epithelial cell sheets transferred into 1.5 mL polypropylene microfuge tubes from individual wells, and quickly frozen at -80°C until extracted. Both extraction and measurement of inositol phosphates were carried out as described previously [5].…”

“…These airway mucins are secreted by two types of cell; goblet cells of the surface epithelium and mucous cells of the submucosal gland. It has been shown that secretion of airway goblet cell mucin is stimulated by extracellular nucleotides [1] by binding to a P 2 purinoceptor located on the cell membrane [2-4], which is coupled to phospholipase C (PLC) through, at least in part, pertussis toxin-sensitive G proteins [5]. Recently, LETHEM et al.…”

“…These airway mucins are secreted by two types of cell; goblet cells of the surface epithelium and mucous cells of the submucosal gland. It has been shown that secretion of airway goblet cell mucin is stimulated by extracellular nucleotides [1] by binding to a P 2 purinoceptor located on the cell membrane [2][3][4], which is coupled to phospholipase C (PLC) through, at least in part, pertussis toxin-sensitive G proteins [5]. Recently, LETHEM et al [4] demonstrated that uridine triphosphate (UTP) is almost equipotent with adenosine triphosphate (ATP) in its ability to stimulate mucin release from human airway epithelial explants [4], suggesting the presence of a receptor type specific both for ATP and UTP in airway epithelial cells, which may regulate the mucin release.…”

Defective ATP‐dependent mucin secretion by cystic fibrosis pancreatic epithelial cells

“…ATP, reported to be a potent secretagogue of electrolyte, has been consequently proposed for use as a therapeutic agent for cystic fibrosis in order to bypass the defective function of CFTR, and to restore chloride secretion in CF patients [5]. Recent reports demonstrate that extracellular ATP is also a very potent secretagogue of mucin secretion in goblet cells from the respiratory tract [6], via a P2-receptor-mediated mechanism [7,8], and of SLPI (secretory leucoprotease inhibitor) in human tracheal gland cells [9].…”