Platelet-activating factor provokes release of mucin-like glycoproteins from guinea pig respiratory epithelial cells via a lipoxygenase-dependent mechanism.
Primary cultures of guinea pig tracheal epithelial cells maintained in an air/liquid interface system that maintains differentiated characteristics were grown to near confluence and exposed for 1 h to platelet-activating factor (PAF) on both apical and basal sides. PAF provoked release of high-molecular-weight mucin-like glycoproteins (MLG) from the cells, with maximal stimulation occurring at 10(-8) and 10(-9) M. The inactive form of PAF, lyso-PAF, was without effect. Indomethacin, the cyclooxygenase inhibitor, did not affect secretion stimulated by PAF, but nordihydroguiaretic acid (NDGA), a mixed cyclooxygenase and lipoxygenase inhibitor, attenuated secretion stimulated by PAF in a concentration-dependent manner. High performance liquid chromatography assay of the culture medium after addition of PAF revealed increased production of 15-, 12-, and 5-hydroxyeicosatetraenoic acids (15-, 12-, and 5-HETEs). The stimulatory effect of PAF on both mucin secretion and formation of HETEs was inhibited by the PAF receptor antagonists, CV-3988 and Ro 19 3704, with Ro 19 3704 acting at a concentration 10-fold lower than CV-3988 in inhibiting both effects. When added exogenously to the cell cultures, the combination of 5-, 12-, and 15-HETEs stimulated MLG release in a concentration-dependent manner. The results suggest that PAF stimulates release of MLG by guinea pig airway epithelium in vitro by a mechanism involving binding of PAF to receptors on epithelial cell surfaces, stimulation of lipoxygenase metabolism of arachidonic acid to HETEs within the epithelium, and stimulation of secretion by these epithelial-derived HETEs via an autocrine or paracrine mechanism.
Adler
K B
KB
Department of Anatomy, College of Veterinary Medicine, North Carolina State University, Raleigh 27606.
Akley
N J
NJ
Glasgow
W C
WC
D000818:Animals; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004848:Epithelium / Q000378:metabolism; D005995:Glyceryl Ethers / Q000494:pharmacology; D006168:Guinea Pigs; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism*; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D008084:Lipoxygenase / Q000502:physiology*; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D009637:Masoprocol / Q000494:pharmacology; D009077:Mucins / Q000378:metabolism*; D010742:Phospholipid Ethers / Q000494:pharmacology; D010972:Platelet Activating Factor / Q000494:pharmacology*; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors; D043562:Receptors, G-Protein-Coupled; D013844:Thiazoles / Q000494:pharmacology; D014132:Trachea / Q000378:metabolism*
D016861:Cyclooxygenase Inhibitors; D005995:Glyceryl Ethers; D006893:Hydroxyeicosatetraenoic Acids; D016859:Lipoxygenase Inhibitors; D009077:Mucins; D010742:Phospholipid Ethers; D010972:Platelet Activating Factor; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D013844:Thiazoles; C039351:platelet activating factor receptor; C053235:Ro 19-3704; D009637:Masoprocol; C037913:CV 3988; D008084:Lipoxygenase; D007213:Indomethacin