title: Generation of thromboxane A2 from highly purified human sinus mast cells after immunological stimulation.
abstract: To better understand metabolites of arachidonic acid generated from human mast cells, the present study assessed the capacity of human mast cells to synthesize thromboxane B2 (TXB2). Anti-IgE challenge of human sinus mast cells resulted in the generation of TXB2 in a dose-dependent manner with a maximal generation of 8.2+/-4.4 ng/10(6) cells (n = 12), which is about 10-fold lower than the maximal generation of prostaglandin D2 (PGD2). Pretreatment of the cells with OKY-046, an inhibitor of TXA synthase, prevented formation of TXB2 in a dose-dependent manner without affecting the generation of PGD2 or leukotriene C4. Experiments using indomethacin or MK-591, a potent FLAP inhibitor, showed that shunting of arachidonic acid did not occur in a single-cell suspension of mast cells. Analysis by RT-PCR revealed that two species of TXA synthase, the full-length TXA synthase mRNA (TXAS-1, 570 BP) and a small quantity of the alternate-spliced form (400 BP), were present in mast cells. When cellular levels of TXAS-1 mRNA were normalized to those of G3PDH mRNA, the relative concentration of TXAS-1 was 2.06+/-0.60 (n = 7) in highly purified sinus mast cells (92.3+/-3.0% pure) and 3.66+/-0.98 (n = 5) in eosinophils.
authors.affiliation: Clinical Research Center, National Sagamihara Hospital, Kanagawa, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Mita
authors.forename: T
authors.initials: T
authors.lastname: Ishii
authors.forename: K
authors.initials: K
authors.lastname: Akiyama
mesh_terms: D058927:5-Lipoxygenase-Activating Proteins; D017398:Alternative Splicing; D000888:Antibodies, Anti-Idiotypic / Q000494:pharmacology; D002352:Carrier Proteins / Q000037:antagonists & inhibitors; D002469:Cell Separation; D004305:Dose-Response Relationship, Drug; D006636:Histamine Release; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D008407:Mast Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D008565:Membrane Proteins / Q000037:antagonists & inhibitors; D008689:Methacrylates / Q000494:pharmacology; D009297:Nasal Mucosa / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D010256:Paranasal Sinuses / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D015230:Prostaglandin D2 / Q000096:biosynthesis; D011804:Quinolines / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D013928:Thromboxane A2 / Q000096:biosynthesis* / Q000235:genetics; D013929:Thromboxane B2 / Q000096:biosynthesis; D013930:Thromboxane-A Synthase / Q000037:antagonists & inhibitors
chemical_list: D058927:5-Lipoxygenase-Activating Proteins; C548592:ALOX5AP protein, human; D000888:Antibodies, Anti-Idiotypic; D002352:Carrier Proteins; D007211:Indoles; D008565:Membrane Proteins; D008689:Methacrylates; D011804:Quinolines; D012333:RNA, Messenger; C026408:anti-IgE antibodies; C078266:MK 0591; D013929:Thromboxane B2; D013928:Thromboxane A2; D013930:Thromboxane-A Synthase; C034364:ozagrel; D015230:Prostaglandin D2