Effects of 1alpha,25-(OH)(2)D(3) on rat growth zone chondrocytes are mediated via cyclooxygenase-1 and phospholipase A(2)

Autor: Victor L. Sylvia, Zvi Schwartz, Barbara D. Boyan, F. Del Toro, R. R. Hardin, David D Dean
Rok vydání: 2001
Předmět:
Indomethacin
Lipoxygenase
Biochemistry
Dinoprostone
Phospholipases A
chemistry.chemical_compound
Phospholipase A2
Chondrocytes
Calcitriol
Stilbenes
medicine
Animals
Masoprocol
Cyclooxygenase Inhibitors
Growth Plate
Lipoxygenase Inhibitors
Umbelliferones
Molecular Biology
Protein kinase C
Cells
Cultured
Nitrobenzenes
Protein Kinase C
Diacylglycerol kinase
Phospholipase A
Sulfonamides
Arachidonic Acid
biology
Cyclooxygenase 2 Inhibitors
Reverse Transcriptase Polymerase Chain Reaction
Membrane Proteins
Cell Biology
Alkaline Phosphatase
Blotting
Northern
Molecular biology
Rats
Isoenzymes
Mechanism of action
chemistry
Cyclooxygenase 2
Prostaglandin-Endoperoxide Synthases
Resveratrol
biology.protein
Cyclooxygenase 1
Arachidonic acid
Proteoglycans
Cyclooxygenase
medicine.symptom
Signal transduction
Thymidine
Zdroj: Europe PubMed Central
ISSN: 0733-1959
Popis: 1alpha,25-(OH)(2)D(3) mediates its effects on growth zone chondrocytes via rapid membrane-associated events as well as through traditional nuclear receptor mechanisms. The membrane-associated signaling pathways include rapid production of diacylglycerol and activation of protein kinase C (PKC), as well as activation of phospholipase A(2) (PLA(2)), increased production of arachidonic acid, and increased production of prostaglandins. This study examined the roles of PLA(2) and cyclooxygenase (Cox) in the mechanism of action of 1alpha,25-(OH)(2)D(3) in these cells to determine whether one or both enzymes catalyze the rate limiting step and whether constitutive or inducible Cox is involved. Cultures were incubated with 1alpha,25-(OH)(2)D(3) for 9 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, growth zone chondrocytes expressed mRNAs for both Cox-1 and Cox-2 and neither Cox was modulated by 1alpha,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). The results showed that Cox-1 inhibition reduced the 1alpha,25-(OH)(2)D(3)-dependent effects on proliferation, differentiation, and matrix production, whereas inhibition of Cox-2 only had an effect on proliferation. The effects of Cox inhibition were not rate limiting, based on experiments in which PLA(2) was activated with melittin or inhibited with quinacrine. However, at least part of the action of 1alpha,25-(OH)(2)D(3) was regulated by metabolism of arachidonic acid to prostaglandins. This supports the hypothesis that 1alpha,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) as a rate-limiting step. PKC regulation may occur at multiple stages in the signal transduction cascade. J. Cell. Biochem. Suppl. 36: 32-45, 2001.
Databáze: OpenAIRE
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