Calcitriol regulation of osteopontin expression in mouse epidermal cells.
Calcitriol regulation of osteopontin expression in mouse epidermal cells.
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DOI：
10.1210/endo.135.3.8070379
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发表时间：
1994-09
期刊：
影响因子：
4.8
通讯作者：
P. Chang;A. Ridall;C. Prince
中科院分区：
文献类型：
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作者：
P. Chang;A. Ridall;C. Prince
我们之前的研究表明，骨化三醇（1 α，25-二羟基维生素D3）诱导克隆小鼠表皮JB6 Cl41.5a细胞以剂量依赖性和代谢物特异性的方式合成和分泌非磷酸化形式的骨桥蛋白（OPN）。为了研究这些细胞中OPN的表达是否受到骨化三醇的转录调节，我们首先确定了骨化三醇诱导的OPN蛋白表达的早期过程和OPN信使RNA （mRNA）的稳态水平。骨化三醇处理JB6 Cl41.5a细胞6小时后，[35S]蛋氨酸标记的OPN分泌增加，8小时后达到最大水平。Northern分析显示，在OPN蛋白合成和分泌之前，OPN mRNA的稳态水平升高。骨化三醇和转录抑制剂放线菌素- d （2-250 ng/ml）对JB6 Cl41.5a细胞的作用表明，骨化三醇诱导的稳态OPN mRNA的积累和OPN蛋白的分泌被放线菌素- d剂量依赖性地抑制。这些数据表明骨化三醇在转录水平上调控OPN的表达。此外，骨化三醇以剂量依赖的方式增加了OPN mRNA的稳态水平。骨化三醇介导的OPN表达增加在转染试验中也被观察到，该转染试验使用了由OPN基因启动子区域的一部分与荧光素酶报告基因融合组成的结构。此外，一项使用5,6-二氯-1- β -d -核糖呋喃基苯并咪唑（一种抑制mRNA合成的腺苷类似物）的研究表明，骨化三醇处理并没有显著增加OPN mRNA的稳定性。这些结果表明骨化三醇通过刺激转录增加OPN mRNA和蛋白的表达。
We previously showed that calcitriol (1 alpha,25-dihydroxyvitamin D3) induces clonal mouse epidermal JB6 Cl41.5a cells to synthesize and secrete a nonphosphorylated form of osteopontin (OPN) in a dose-dependent and metabolite-specific manner. To investigate whether OPN expression is transcriptionally regulated by calcitriol in these cells, we first determined the early time course of calcitriol-induced expression of OPN protein and steady state levels of OPN messenger RNA (mRNA). Calcitriol treatment of JB6 Cl41.5a cells for 6 h caused increased secretion of [35S]methionine-labeled OPN, with maximal levels attained after 8 h of treatment. Northern analyses showed that steady state levels of OPN mRNA increase before the synthesis and secretion of OPN protein. Treatment of JB6 Cl41.5a cells with calcitriol and the transcriptional inhibitor actinomycin-D (2-250 ng/ml) indicated that calcitriol-induced accumulation of steady state OPN mRNA and secretion of OPN protein were dose dependently inhibited by actinomycin-D. These data suggest that calcitriol regulates the expression of OPN at the level of transcription. Furthermore, calcitriol increased the steady state level of OPN mRNA in a dose-dependent manner. Calcitriol-mediated increases in OPN expression were also observed in a transfection assay using a construct consisting of a portion of the promoter region of the OPN gene fused to the luciferase reporter gene. In addition, a study using 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole, an adenosine analog that inhibits mRNA synthesis, showed that calcitriol treatment did not significantly increase the stability of OPN mRNA. These findings suggest that calcitriol increases the expression of OPN mRNA and protein by stimulating transcription.