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Thrombin induces proliferation of osteoblast‐like cells through phosphatidylcholine hydrolysis
Author(s) -
Suzuki Atsushi,
Kozawa Osamu,
Shinoda Junji,
Watanabe Yasuko,
Saito Hidehiko,
Oiso Yutaka
Publication year - 1996
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/(sici)1097-4652(199607)168:1<209::aid-jcp25>3.0.co;2-0
Subject(s) - thrombin , phospholipase c , chemistry , biochemistry , phosphatidylcholine , phospholipase d , diacylglycerol kinase , protein kinase c , biology , kinase , phospholipid , signal transduction , platelet , immunology , membrane
We examined the effect of thrombin on phosphatidylcholine‐hydrolyzing phospholipase D activity in osteoblast‐like MC3T3‐E1 cells. Thrombin stimulated the formation of choline dose dependently in the range between 0.01 and 1 U/ml, but not the phosphocholine formation. Diisopropylfluorophosphate (DFP)‐inactivated thrombin had little effect on the choline formation. The combined effects of thrombin and 12‐ O ‐tetradecanoylphorbol‐13‐acetate, a protein kinase C‐activating phorbol ester, on the choline formation were additive. Staurosporine, an inhibitor of protein kinases, had little effect on the thrombin‐induced formation of choline. Combined addition of thrombin and NaF, an activator of heterotrimeric GTP‐binding protein, did not stimulate the formation of choline further. Pertussis toxin had little effect on the thrombin‐induced formation of choline. Thrombin stimulated Ca 2+ influx from extracellular space time and dose dependently. The depletion of extracellular Ca 2+ by EGTA exclusively reduced the thrombin‐induced choline formation. Thrombin had only a slight effect on phosphoinositide‐hydrolyzing phospholipase C activity. Thrombin induced diacylglycerol formation and DNA synthesis, and increased the number of MC3T3‐E1 cells, but DFP‐inactivated thrombin did not. Thrombin suppressed both basal and fetal calf serum‐induced alkaline phosphatase activity in these cells. Propranolol, an inhibitor of phosphatidic acid phosphohydrolase, inhibited both the thrombin‐induced diacylglycerol formation and DNA synthesis. These results suggest that thrombin stimulates phosphatidylcholine‐hydrolyzing phospholipase D due to self‐induced Ca 2+ influx independently of protein kinase C activation in osteoblast‐like cells and that its proliferative effect depends on phospholipase D activation. © 1996 Wiley‐Liss, Inc.