TY - JOUR
T1 - Effect of prostaglandin E2 on phospholipase D activity in osteoblast‐like MC3T3‐E1 cells
AU - Oiso, Yutaka
AU - Suzuki, Atsushi
AU - Kozawa, Osamu
PY - 1995/8
Y1 - 1995/8
N2 - Recent evidence indicates that phosphatidylcholine breakdown by phospholipase D (PLD) is an important cellular control mechanism. We investigated the signaling pathway participating in prostaglandin E2 (PGE2)–induced PLD activation in osteoblast‐like MC3T3‐E1 cells. PGE2 stimulated PLD activity, as measured by choline generated from phosphatidylcholine, just after the stimulation. The reaction reached a plateau 15 minutes later. PGE2 stimulated PLD activity in a dose‐related manner and also increased inositol phosphate (IP) formation. However, the EC50 value for PGE2‐induced IP formation is lower than that for PLD activation. 12‐O‐Tetradecanoylphorbol‐13‐acetate (TPA), a protein kinase C (PKC) activator, stimulated PLD activity, and a combination of PGE2 and TPA potentiated it in an additive manner. Although NaF, a heterotrimeric GTP‐binding protein activator, significantly stimulated PLD activity, this effect was not augmented by combination with PGE2. PGE2‐induced PLD activity was markedly suppressed by either chelating extracellular Ca2+ by EGTA or pertussis toxin. These findings suggest that osteoblasts might have at least two PLD activation mechanisms which involve PKC‐dependent or ‐independent pathways. However, present results indicate that PKC is unlikely to be essential to PGE2‐induced PLD activation. On the contrary, pertussis toxin‐sensitive GTP‐binding protein and extracellular Ca2+ might play important roles in the pathway of PGE2‐induced PLD activation.
AB - Recent evidence indicates that phosphatidylcholine breakdown by phospholipase D (PLD) is an important cellular control mechanism. We investigated the signaling pathway participating in prostaglandin E2 (PGE2)–induced PLD activation in osteoblast‐like MC3T3‐E1 cells. PGE2 stimulated PLD activity, as measured by choline generated from phosphatidylcholine, just after the stimulation. The reaction reached a plateau 15 minutes later. PGE2 stimulated PLD activity in a dose‐related manner and also increased inositol phosphate (IP) formation. However, the EC50 value for PGE2‐induced IP formation is lower than that for PLD activation. 12‐O‐Tetradecanoylphorbol‐13‐acetate (TPA), a protein kinase C (PKC) activator, stimulated PLD activity, and a combination of PGE2 and TPA potentiated it in an additive manner. Although NaF, a heterotrimeric GTP‐binding protein activator, significantly stimulated PLD activity, this effect was not augmented by combination with PGE2. PGE2‐induced PLD activity was markedly suppressed by either chelating extracellular Ca2+ by EGTA or pertussis toxin. These findings suggest that osteoblasts might have at least two PLD activation mechanisms which involve PKC‐dependent or ‐independent pathways. However, present results indicate that PKC is unlikely to be essential to PGE2‐induced PLD activation. On the contrary, pertussis toxin‐sensitive GTP‐binding protein and extracellular Ca2+ might play important roles in the pathway of PGE2‐induced PLD activation.
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U2 - 10.1002/jbmr.5650100807
DO - 10.1002/jbmr.5650100807
M3 - Article
C2 - 8585421
AN - SCOPUS:0028977892
VL - 10
SP - 1185
EP - 1190
JO - Journal of Bone and Mineral Research
JF - Journal of Bone and Mineral Research
SN - 0884-0431
IS - 8
ER -