title: The human megakaryocytic cell line UT-7/TPO responds to platelet agonists with intracellular Ca2+ elevation and P-selectin expression.
abstract: Megakaryocytes have several signal transduction cascades that are similar, but not identical to platelet activation signals. In order to understand platelet signals in detail, it is useful to compare the similarities and/or differences between platelets and megakaryocytes. We evaluated platelet activation signals related to three kinds of Gq protein-coupled receptors using the megakaryocytic cell line UT-7/TPO. It was found that UT-7/TPO responded to thrombin, resulting in a continuous elevation of the [Ca2+]i (intracellular Ca2+) and P-selectin expression on the surface of the cells. Activation of integrin αIIbβ3 and thromboxane generation was not detected by any of the three stimulations. Taken together, although strong [Ca2+]i elevation by thrombin stimulation caused further P-selection expression, we could detect [Ca2+]i elevation, which is thought to be the individual signals through the thrombin, thromboxane A2 or ADP receptor, without considering the secondary signalling caused by αIIbβ3 activation and the arachidonic acid cascade using UT-7/TPO.
authors.affiliation: Cardiovascular-Metabolics Research Laboratories, Daiichi-Sankyo Co Ltd 1258, Hiromachi, Shinagawa-ku, Tokyo, Japan. kawaguchi.tatsuya.ns@daiichisankyo.co.jp
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kawaguchi
authors.forename: Ryuji
authors.initials: R
authors.lastname: Hashimoto
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Nawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yokota
mesh_terms: D016718:Arachidonic Acid / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000378:metabolism; D006801:Humans; D008533:Megakaryocytes / Q000378:metabolism*; D019007:P-Selectin / Q000378:metabolism*; D015539:Platelet Activation; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism; D013917:Thrombin / Q000378:metabolism; D013928:Thromboxane A2 / Q000378:metabolism
chemical_list: D019007:P-Selectin; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D016718:Arachidonic Acid; D013928:Thromboxane A2; D013917:Thrombin; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D002118:Calcium