Intracellular Signaling Mechanism of Bradykinin in Osteoblast-Like Cells: Comparison with Prostaglandin E2.

Tokuda, Harukuni; Kotoyori, Jun; Oiso, Yutaka; Kozawa, Osamu

doi:10.1507/endocrj.41.189

Cited by 8 publications

(4 citation statements)

References 24 publications

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“…To investigate whether p110 is involved in receptor-mediated, G protein-coupled signaling in osteoblasts, the ability of bradykinin to stimulate tyrosine phosphorylation of p110 was evaluated. Bradykinin receptors are seven-transmembrane receptors considered to couple to the G q class of G␣ proteins and are present on MC3T3-E1 cells (23).…”

Section: Fluoroaluminate Induces Tyrosine Phosphorylation Of a 110-kdmentioning

confidence: 99%

Fluoroaluminate Induces Activation and Association of Src and Pyk2 Tyrosine Kinases in Osteoblastic MC3T3-E1 Cells

Jeschke

Standke

Šuša

1998

Journal of Biological Chemistry

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Fluoride has been known as a bone-forming agent for more than 100 years. Together, the occurrence of osteosclerosis in miners exposed to a mineral consisting of sodium aluminum fluoride (Na 3 AlF 6 ), the effect of fluoridation of drinking water on bone mass in humans, as well as recent animal studies suggest that fluoride in complex with aluminum is capable of increasing bone formation (reviewed in Refs. 1 and 2). However, a narrow therapeutic window and the questionable quality of newly formed bone prevented the wide use of fluoride for the treatment of osteoporotic patients. A promising new treatment using fluoride has recently been offered in the form of slow-release sodium fluoride (reviewed in Ref. 3). Despite difficulties in its therapeutic use, fluoride remains an interesting bone anabolic agent. Understanding the molecular actions of fluoride on bone is expected to enable the development of drugs that would mimic its anabolic action and could overcome problems of the narrow therapeutic window and side effects.Little is known about the molecular mechanism of fluoride action in bone at the cellular level. Fluoride in a complex with aluminum (fluoroaluminate, most likely AlF 4 Ϫ ) (4) binds to ␣-subunits of heterotrimeric G proteins in vitro and activates G protein-mediated intracellular signaling pathways (5-8). Numerous reports indicate that in cultures of isolated primary osteoblastic cells as well as osteoblastic cell lines, fluoride and fluoroaluminate can induce proliferation (2, 9 -11), although this effect seems to be restricted to a certain population of osteoblastic cells (12). Activation of several enzymes involved in intracellular signal transduction has been implicated in mediating the mitogenic signal of fluoride (including phospholipase C, diglyceride kinase, phospholipase D, tyrosine kinases, Erk1, Erk2, and p70 S6K ) as well as the inhibition of tyrosine phosphatases and adenylate cyclase (2, 13-17).We (17) and others (2, 18) have recently reported that fluoroaluminate and fluoride increase protein tyrosine phosphorylation in osteoblast-like cells. In our system, fluoroaluminate induced prominent tyrosine phosphorylation of several proteins with apparent molecular masses of ϳ70, 120, and 130 kDa (17). However, the identity of tyrosine kinases mediating fluoroaluminate-induced tyrosine phosphorylation has remained elusive. In this study, we describe the tyrosine phosphorylation of a previously undetected 110-kDa protein in response to treatment of MC3T3-E1 cells with fluoroaluminate. The phosphorylation of this protein was weaker than the tyrosine phosphorylation of major proteins that were previously described, and its resolution from the major 120-kDa protein was critical for its detection. Furthermore, we demonstrate that this 110-kDa protein is immunologically indistinguishable from Pyk2 (proline-rich tyrosine kinase 2), a recently described tyrosine kinase shown to be

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Section: Fluoroaluminate Induces Tyrosine Phosphorylation Of a 110-kdmentioning

confidence: 99%

Fluoroaluminate Induces Activation and Association of Src and Pyk2 Tyrosine Kinases in Osteoblastic MC3T3-E1 Cells

Jeschke

Standke

Šuša

1998

Journal of Biological Chemistry

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“…This results in the cleavage of PIP2 with the concurrent release of inositol ( 1,4,S)-trisphosphate and DG formation. Among these products inositol (1,4,5)-trisphosphatc serve :IS second messenger for the mobilization of calcium from intracellular stores."") Accompanying PLD activation, we observed a net increase in [Ca" Ii as measured by Fura-2 fluorescence.…”

Section: Discussionmentioning

confidence: 99%

Role of protein kinase Cα, arf, and cytoplasmic calcium transients in phospholipase D activation by sodium fluoride in osteoblast-like cells

Bourgoin

Harbour

Poubelle

1996

Journal of Bone and Mineral Research

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The effect of fluoride on phospholipase D (PLD) activation was studied using in vitro culture of Saos-2, MG-63 osteosarcoma cells, and normal osteoblast-like cells derived from human bone explants. Millimolar concentrations of NaF induced a significant accumulation of phosphatidylethanol (PEt) in Saos-2 cells but not in MG-63 and normal osteoblast-like cells. PLD activation was evident at 15 mM and concentration-dependent up to 50 mM. This stimulation was inhibited by deferoxamine, a chelator of Al3+, suggesting that PLD activation involves fluoride-sensitive G proteins. A good correlation was found between the levels of intracellular free Ca2+ and the activation of PLD. The time courses of the two responses were nearly identical. The ability of NaF to induce both responses was largely dependent on the presence of extracellular calcium. The calcium ionophore A23187 reproduced the effect of NaF, and this effect was antagonized by EGTA, suggesting that PLD activation was, at least in part, a calcium-regulated event. Phorbol 12-myristate 13-acetate (PMA) also stimulated PLD activity in human bone cells. Protein kinase C alpha (PKC alpha) and epsilon were expressed in Saos-2 cells. Acute pretreatment of cells with PMA reduced concomitantly the amounts of PKC alpha, but not of PKC epsilon, and the subsequent activation of PLD elicited by PKC activators. The PLD response to NaF was not attenuated but rather enhanced by down-regulation of PKC alpha. Therefore, PKC-alpha-induced PLD activation is unlikely to mediate the effect of NaF. Moreover, PMA and NaF showed a supraadditive effect on PLD activation in Saos-2 cells. This stimulation, in contrast to NaF alone, was not reduced by EGTA. Hence, mobilization of calcium by NaF cannot account for the enhanced PLD activation in response to PMA stimulation. Membrane Arf and RhoA contents were assessed by Western immunoblot analyses. Membranes derived from NaF-stimulated Saos-2 cells contained more Arf and RhoA when compared with membranes derived from control or PMA-stimulated cells. Translocation of the small GTPases was calcium-independent. We conclude that PLD activation by NaF in Saos-2 cells includes a fluoride-sensitive G protein, increases in the levels of intracellular calcium, and Arf/RhoA redistribution to membranes. The results also indicate that the NaF-induced Arf/RhoA translocation exerts in concert with PMA-activated PKC alpha a synergistic effect on the activation of PLD in Saos-2 cells.

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“…The experiments were performed as described by Tokuda et al(1994) with some modifications. The dispersed salivary glands were suspended in a buffer containing 140 mM NaCl, 1 mM MgCh, 5 mM KCl, 1.5 mM CaCh, 10 mM HEPES, Tris (pH 7.4), 5 mM glucose, 0.1 % bovine serum albumin (BSA) and preincubated at 37°C for 10 min.…”

Section: Assay Of 45 Ca 2 + Influxmentioning

confidence: 99%

A specific prostaglandin E2 receptor and its role in modulating salivary secretion in the female tick, Amblyomma americanum (L.)

Qian¹

1997

Insect Biochemistry and Molecular Biology

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Intracellular Signaling Mechanism of Bradykinin in Osteoblast-Like Cells: Comparison with Prostaglandin E2.

Cited by 8 publications

References 24 publications

Fluoroaluminate Induces Activation and Association of Src and Pyk2 Tyrosine Kinases in Osteoblastic MC3T3-E1 Cells

Fluoroaluminate Induces Activation and Association of Src and Pyk2 Tyrosine Kinases in Osteoblastic MC3T3-E1 Cells

Role of protein kinase Cα, arf, and cytoplasmic calcium transients in phospholipase D activation by sodium fluoride in osteoblast-like cells

A specific prostaglandin E2 receptor and its role in modulating salivary secretion in the female tick, Amblyomma americanum (L.)

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