title: A novel cell-permeable cromoglycate derivative inhibits type I Fc epsilon receptor mediated Ca2+ influx and mediator secretion in rat mucosal mast cells.
abstract: Type I Fc epsilon receptor (Fc epsilon RI) mediated Ca2+ uptake and secretion of rat serosal mast cells have been shown to be inhibited by disodium 1,3-bis [(2'-carboxylatochromon-5'-yl) oxy]-2-hydroxypropane (disodium cromoglycate, DSCG), which is widely employed in the treatment of allergic asthma [Foreman et al. (1977) Br. J. Pharmacol. 59, 473P-474P; Cox (1967) Nature (London) 216, 1328-1329]. This drug was also found to modify the protein phosphorylation pattern of these mast cells. [Theoharides et al. (1980) Science 207, 80-82]. We have isolated by affinity chromatography on a water-insoluble cromoglycate-carrying matrix a cytosolic enzyme recently identified as a nucleoside 5'-diphosphate kinase. In order to examine a possible intracellular activity of the drug, a cell-permeant cromoglycate derivative, 1,3-bis [[2'-[[(acetoxymethyl)oxy]carbonyl]chromon-5'- yl]oxy]-2-hydroxypropane [bis(acetoxymethyl) cromoglycate, CG/AM], has been synthesized, and its uptake and effect on the Fc epsilon RI-mediated exocytosis of mast cells was investigated. A tritium-labeled CG/AM derivative, used as radioactive tracer, was found to permeate mucosal mast cells of the rat line RBL-2H3 and accumulate intracellularly up to 40-fold its extracellular concentration following hydrolysis by cytoplasmic hydrolases. A CG/AM dose dependent inhibition of the Fc epsilon RI-induced mediator secretion was observed in RBL-2H3 cells loaded with this compound (I50 approximately 40 microM extracellular CG/AM). A similar dose-dependent inhibition was observed for both the Fc epsilon RI-mediated transient rise in the concentration of cytosolic free Ca2+ ions [( Ca2+]i) and the net Ca2+ influx, as monitored by the fluorescent indicator Quin2 and the radioactive tracer 45Ca2+, respectively. These results clearly show that cell-permeant cromoglycate inhibits the Fc epsilon RI-mediated Ca2+ influx into the cell and further underscore the dominant role of this process in the coupling of stimulus to secretion in RBL cells. Furthermore, with the identification of nucleoside 5'-diphosphate kinase as a potential intracellular target for CG activity, distinct mechanisms of action may be inferred for cell-permeant and nonpermeant forms of CG.
authors.affiliation: Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: S
authors.initials: S
authors.lastname: Hemmerich
authors.forename: D
authors.initials: D
authors.lastname: Sijpkens
authors.forename: I
authors.initials: I
authors.lastname: Pecht
mesh_terms: D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte / Q000502:physiology*; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D004205:Cromolyn Sodium / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology; D006636:Histamine Release / Q000187:drug effects*; D006868:Hydrolysis; D007073:Immunoglobulin E / Q000502:physiology; D007202:Indicators and Reagents; D007700:Kinetics; D008407:Mast Cells / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D009092:Mucous Membrane / Q000502:physiology; D010766:Phosphorylation; D051381:Rats; D011961:Receptors, Fc / Q000187:drug effects / Q000502:physiology*; D017455:Receptors, IgE; D012701:Serotonin / Q000378:metabolism
chemical_list: D000944:Antigens, Differentiation, B-Lymphocyte; D007202:Indicators and Reagents; D011961:Receptors, Fc; D017455:Receptors, IgE; C067252:1,3-bis((2'-(((acetoxymethyl)oxy)carbonyl)chromon-5'-yl)oxy)-2-hydroxypropane; D012701:Serotonin; D007073:Immunoglobulin E; D004205:Cromolyn Sodium; D002118:Calcium