Effect of 1,25(OH)2D3 and 24,25(OH)2D3 on calcium ion fluxes in costochondral chondrocyte cultures

Langston, G. G.; Swain, L. D.; Schwartz, Zvi; Toro, F. Del; Gomez, Ruben; Boyan, Barbara D.

doi:10.1007/bf02555924

Cited by 57 publications

(27 citation statements)

References 25 publications

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“…1,25(OH) 2 D 3 elicits a variety of rapid membrane-mediated responses in the more mature growth zone cells (GCs) derived from the prehypertrophic and upper hypertrophic zones of the growth plate. These effects include changes in Ca 2+ flux (7) and membrane fluidity. (1) There is a quick stimulation of phospholipase A 2 (PLA 2 ) activity, resulting in an increase in arachidonic acid (AA) release (8) and prostaglandin E 2 production.…”

Section: Introductionmentioning

confidence: 99%

“…(16) In the rat costochondral growth plate, 24,25(OH) 2 D 3 almost exclusively regulates the less mature resting zone cells (RCs), but not the GC cells. In RC cells, 24,25(OH) 2 D 3 modulates Ca 2+ ion flux (7) and membrane fluidity. (1) It regulates membrane phospholipid metabolism through down-regulation of PLA 2 (8) and up-regulation of phospholipase D. (17) This results in changes in AA turnover and release and production of prostaglandin E 2 (9) and DAG.…”

Section: Introductionmentioning

confidence: 99%

“…AA release (8) and prostaglandin production, (9) as well as inositol trisphosphate and DAG production, (10) increased Ca 2+ influx, (7) and increased membrane fluidity. (1) In contrast, 24,25(OH) 2 D 3 decreases PLA 2 (42) and has no effect on phospholipase C. (11) AA release is initially decreased, (8) as is prostaglandin production.…”

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“…(1) In contrast, 24,25(OH) 2 D 3 decreases PLA 2 (42) and has no effect on phospholipase C. (11) AA release is initially decreased, (8) as is prostaglandin production. (9) DAG is increased via phospholipase D, (18) but Ca 2+ influx is inhibited (7) and membrane fluidity is decreased.…”

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Physiological Importance of the 1,25(OH)2D3 Membrane Receptor and Evidence for a Membrane Receptor Specific for 24,25(OH)2D3

Pedrozo

Schwartz

Rimes

et al. 1999

Journal of Bone and Mineral Research

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Physiological Importance of the 1,25(OH)2D3 Membrane Receptor and Evidence for a Membrane Receptor Specific for 24,25(OH)2D3

Pedrozo

Schwartz

Rimes

et al. 1999

Journal of Bone and Mineral Research

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“…© 2000 Recent evidence has shown that 24R,25-(OH) 2 D 3 exerts effects on chondrocytes in the rat growth plate (Pedrozo et al, 1999b) and chick fracture callus (Kato et al, 1998) through specific 24R,25-(OH) 2 D 3 -activated membrane receptors. The signaling mechanisms involved in the membrane-mediated response include rapid changes in membrane fluidity (Swain et al, 1993) and Ca 2ϩ ion flux (Langston et al, 1990). Two interrelated pathways participate in the signal transduction process, both of which depend on the metabolism of membrane phospholipids.…”

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24R,25-(OH)2D3 mediates its membrane receptor-dependent effects on protein kinase C and alkaline phosphatase via phospholipase A2 and cyclooxygenase-1 but not cyclooxygenase-2 in growth plate chondrocytes

Schwartz¹,

Sylvia

Toro

et al. 2000

J. Cell. Phys.

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Recent studies have shown that 24R,25-(OH)(2)D(3) mediates its effects on growth plate chondrocytes via membrane receptors. This study examined the roles of phospholipase A(2) (PLA(2)) and cyclooxygenase (Cox) in the mechanism of action of 24R, 25-(OH)(2)D(3) in resting zone chondrocytes in order to determine whether the activity of one or both enzymes provides a regulatory checkpoint in the signaling pathway resulting in increased protein kinase C (PKC) activity. We also determined whether constitutive or inducible Cox is involved. Cultures were incubated with 24R, 25-(OH)(2)D(3) for 90 min to measure PKC or for 24 h to measure physiological responses ([(3)H]-thymidine incorporation, alkaline phosphatase-specific activity, [(35)S]-sulfate incorporation). Based on RT-PCR and Northern blot analysis, resting zone chondrocytes express mRNAs for both Cox-1 and Cox-2. Levels of mRNA for both proteins were unchanged from control levels after a 24-h incubation with 24R,25-(OH)(2)D(3). To examine the role of Cox, the cultures were also treated with resveratrol (a specific inhibitor of Cox-1), NS-398 (a specific inhibitor of Cox-2), or indomethacin (a general Cox inhibitor). Cox-1 inhibition resulted in effects on proliferation, differentiation, and matrix production typical of 24R, 25-(OH)(2)D(3). In contrast, inhibition of Cox-2 had no effect, indicating that 24R,25-(OH)(2)D(3) exerts its effects via Cox-1. Inhibition of Cox-1 also blocked 24R,25-(OH)(2)D(3)-dependent increases in PKC. Activation of PLA(2) with melittin inhibited 24R, 25-(OH)(2)D(3)-dependent stimulation of PKC, and inhibition of PLA(2) with quinacrine stimulated PKC in response to 24R, 25-(OH)(2)D(3). Inclusion of resveratrol reduced the melittin-dependent inhibition of PLA(2) and caused an increase in quinacrine-stimulated PLA(2) activity. Metabolism of arachidonic acid to leukotrienes is not involved in the response to 24R, 25-(OH)(2)D(3) because inhibition of lipoxygenase had no effect. The effect of 24R,25-(OH)(2)D(3) was specific because 24S,25-(OH)(2)D(3), the biologically inactive stereoisomer, failed to elicit a response from the cells. These results support the hypothesis that 24R, 25-(OH)(2)D(3) exerts its effects via more than one signaling pathway and that these pathways are interrelated via the modulation of PLA(2). PKC regulation may occur at multiple stages in the signal transduction cascade.

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Surface roughness modulates the response of MG63 osteoblast-like cells to 1,25-(OH)2D3 through regulation of phospholipase A2 activity and activation of protein kinase A

Lohmann

Sagun

Sylvia

et al. 1999

J. Biomed. Mater. Res.

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Implant surface roughness influences osteoblast proliferation, differentiation, and local factor production. Moreover, the responsiveness of osteoblasts to systemic hormones such as 1, 25-(OH)(2)D(3) is altered by the effects of surface roughness; on the roughest Ti surfaces the effects of roughness and 1, 25-(OH)(2)D(3) are synergistic. Prostaglandin E(2) (PGE(2)) appears to be involved in mediating the effects of surface roughness on the cells, as well as in the response to 1,25-(OH)(2)D(3). However, it is not yet known through which signaling pathways surface roughness exerts its effects on the response of osteoblasts to 1, 25-(OH)(2)D(3). The present study examined the potential role of protein kinase A (PKA), phospholipase A(2)(PLA(2)), and protein kinase C (PKC) in this process. MG63 osteoblast-like human osteosarcoma cells were cultured on cpTi disks with R(a) values of 0. 54 microm (PT), 4.14 microm (SLA), or 4.92 microm (TPS). PKA was inhibited by adding H8 to the cultures; similarly, PLA(2) was inhibited with quinacrine or activated with melittin, and PKC was inhibited with chelerythrine. Inhibitors or activators were included in the culture media through the entire culture period or for the last 24 h of culture. In addition, cultures were treated for 24 h with inhibitors or activators in the presence of 1,25-(OH)(2)D(3). The effects on cell number and alkaline phosphatase specific activity were determined after 24 h; PKC activity was determined after 9 min and at 24 h. Cell number was reduced on rough surfaces, and alkaline phosphatase activity was increased. 1,25-(OH)(2)D(3) had a synergistic effect with surface roughness on alkaline phosphatase. However, neither surface roughness nor 1,25-(OH)(2)D(3) had an effect on PKC. H8 treatment for 24 h inhibited cell number and alkaline phosphatase on all surfaces; however, when it was present throughout the culture period, the PKA inhibitor had no effect on cell number, but decreased alkaline phosphatase-specific activity. H8 reduced the 1,25-(OH)(2)D(3)-mediated effect on cell number and alkaline phosphatase. Quinacrine inhibited cell proliferation and alkaline phosphatase on all surfaces and further reduced the 1,25-(OH)(2)D(3)-dependent decreases in both parameters. Melittin had no effect when applied for 24 h and did not modify the 1,25-(OH)(2)D(3) effect; however, when present throughout the culture period, it caused a decrease in proliferation and an increase in enzyme activity. Chelerythrine, the PKC inhibitor, only inhibited cell proliferation when it was present throughout the entire culture period. However, it decreased alkaline phosphatase in cultures treated for 24 h, but increased enzyme activity when it was present for the entire culture period. The results indicate that surface roughness and 1,25-(OH)(2)D(3) both mediate their effects through PLA(2) which catalyzes the rate-limiting step in PGE(2) production. Further downstream, PGE(2) activates PKA. Surface roughness-dependent effects are also mediated through PKC, but only after the cells ha...

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Effect of 1,25(OH)2D3 and 24,25(OH)2D3 on calcium ion fluxes in costochondral chondrocyte cultures

Cited by 57 publications

References 25 publications

Physiological Importance of the 1,25(OH)2D3 Membrane Receptor and Evidence for a Membrane Receptor Specific for 24,25(OH)2D3

Physiological Importance of the 1,25(OH)2D3 Membrane Receptor and Evidence for a Membrane Receptor Specific for 24,25(OH)2D3

24R,25-(OH)2D3 mediates its membrane receptor-dependent effects on protein kinase C and alkaline phosphatase via phospholipase A2 and cyclooxygenase-1 but not cyclooxygenase-2 in growth plate chondrocytes

Surface roughness modulates the response of MG63 osteoblast-like cells to 1,25-(OH)2D3 through regulation of phospholipase A2 activity and activation of protein kinase A

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