Functional platelet-activating factor receptors linked to inositol lipid hydrolysis, calcium mobilization and tyrosine kinase activity in the human endometrial HEC-1B cell line.
Platelet-activating factor (PAF; sn-1-O-alkyl-2-acetyl-sn-glycero-3- phosphocholine) is thought to be an important mediator of embryo-endometrial interactions in early pregnancy, and an understanding of its role in the establishment of early human pregnancy can only follow an understanding of its mechanism of action. In a human endometrial epithelial cell line, HEC-1B, the presence of mRNA encoding the platelet-activating factor receptor was demonstrated by reverse transcription-polymerase chain reaction. The presence of functional receptors was shown by inositol trisphosphate accumulation and a rise in the concentration of intracellular free calcium evoked by platelet-activating factor in myo-[2-3H]inositol-labelled and fura-2-loaded cells, respectively. Platelet-activating factor evoked rapid and concentration-dependent increases in the concentration of intracellular free calcium and inositol trisphosphate that were inhibited by the platelet-activating factor receptor antagonist WEB 2086, indicating that the responses are receptor mediated. Inositol trisphosphate accumulation evoked by platelet-activating factor was unaffected by pretreatment with pertussis toxin. Platelet-activating factor also stimulated the tyrosine phosphorylation of at least two major proteins of 80 kDa and 44 kDa; the smaller protein is an isoform of mitogen-activated protein kinase. These results show that functional platelet-activating factor receptors are located on the endometrial epithelial cell line HEC-1B and are linked to inositol lipid hydrolysis, calcium mobilization and tyrosine kinase activity.
Ahmed
A
A
Centre for Clinical Research in Immunology and Signalling, University of Birmingham, Medical School, Edgbaston, UK.
Sage
S O
SO
Plevin
R
R
Shoaibi
M A
MA
Sharkey
A M
AM
Smith
S K
SK
D001381:Azepines / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D004717:Endometrium / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D016257:Fura-2; D006801:Humans; D006868:Hydrolysis; D007294:Inositol / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D050356:Lipid Metabolism; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D014230:Triazoles / Q000494:pharmacology
D001381:Azepines; D010972:Platelet Activating Factor; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D014230:Triazoles; C039351:platelet activating factor receptor; C052518:WEB 2086; D007294:Inositol; D015544:Inositol 1,4,5-Trisphosphate; D011505:Protein-Tyrosine Kinases; D002118:Calcium; D016257:Fura-2