Response of a human megakaryocytic cell line to thrombin: increase in intracellular free calcium and mitogen release.
The CHRF-288-11 cell line has been previously shown to exhibit properties consistent with a megakaryocytic origin. The response of these cells to thrombin has now been investigated. Thrombin treatment of CHRF-288-11 cells results in both an increase in intracellular free calcium levels and secretion of mitogenic activity and beta-thromboglobulin. Cell viability is not affected. The mitogenic activity released from the cells is due primarily to the presence of basic fibroblast growth factor. Immunohistochemical data indicate a packaging of basic fibroblast growth factor into granular structures. Trypsin and phorbol 12-myristate 13-acetate also initiate release of mitogenic activity from this cell line, whereas under non-stirred conditions collagen and ADP do not. Through measurements of intracellular calcium levels it was determined that thrombin pretreatment of cells ablates a further response to thrombin, but does not block an increase in intracellular calcium levels due to trypsin. This suggests that these two agonists may act through different mechanisms. The thrombin-induced release reaction is inhibited almost completely by the reagents hirudin and dipyridamole, and only partially by indomethacin. These data indicate that the CHRF-288-11 cell line should provide an excellent model system in which to study the packaging of factors into granules which undergo regulated release.
Jones
C L
CL
Department of Molecular Genetics, University of Cincinnati College of Medicine, OH 45267-0524.
Witte
D P
DP
Feller
M J
MJ
Fugman
D A
DA
Dorn
G W
GW
Lieberman
M A
MA
D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D016222:Fibroblast Growth Factor 2 / Q000032:analysis; D006801:Humans; D008533:Megakaryocytes / Q000187:drug effects* / Q000378:metabolism; D008934:Mitogens / Q000378:metabolism*; D008954:Models, Biological; D010978:Platelet Factor 4 / Q000032:analysis; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013917:Thrombin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D016212:Transforming Growth Factor beta / Q000032:analysis; D014357:Trypsin / Q000494:pharmacology; D001620:beta-Thromboglobulin / Q000032:analysis
D008934:Mitogens; D016212:Transforming Growth Factor beta; D001620:beta-Thromboglobulin; D016222:Fibroblast Growth Factor 2; D010978:Platelet Factor 4; D014357:Trypsin; D013917:Thrombin; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium