Murine osteoblast interleukin 4 receptor expression: upregulation by 1,25 dihydroxyvitamin D3.
Murine osteoblast interleukin 4 receptor expression: upregulation by 1,25 dihydroxyvitamin D3.
复制标题
小鼠成骨细胞白细胞介素 4 受体表达：1,25 二羟基维生素 D3 上调。
DOI：
10.1002/jcb.240530205
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发表时间：
1993
影响因子：
4
通讯作者：
Ohara,J
中科院分区：
文献类型：
--
作者：
Lacey,DL;Erdmann,JM;Tan,HL;Ohara,J
免疫细胞因子白细胞介素4在骨骼代谢中的作用已被新认识。虽然许多细胞的相互作用最终决定了骨量，但我们通过表征MC3T3‐E1 （MC3T3）小鼠成骨细胞中IL‐4受体（IL‐4R）的表达，研究了成骨细胞可能是骨中IL‐4靶点的可能性。基于125I‐IL‐4结合，MC3T3细胞表达大量IL‐4受体（125I‐IL‐4 Bmax = 3000 - 7500个位点/细胞，125I‐IL‐4 K = 13-40 pM），其亲和力与IL‐4应答T细胞系表达的IL‐4受体相似。单克隆抗IL - 4R抗体（M1）阻断特异性MC3T3125I - IL - 4结合，MC3T3总细胞RNA含有全长IL - 4R mRNA，利用IL - 4R引物进行逆转录DNA扩增和Northern blot分析检测。在功能上，IL‐4处理MC3T3细胞导致细胞增殖增加（10-20%）和碱性磷酸酶水平抑制（20-40%）。虽然甲状旁腺激素（PTH）暴露不影响IL - 4R水平，但维生素d3处理以时间依赖性的方式增强了MC3T3125I - IL - 4的结合，在暴露24小时后达到三倍，代谢物特异性表明维生素D受体的参与。平衡结合研究表明，125 (OH) 2d3对MC3T3125I - IL - 4结合的影响是由于IL - 4R Bmax的增加。环己亚胺处理抑制1,25 (OH)2D3诱导的IL - 4R上调，表明蛋白质合成是必需的。此外，类固醇以时间和浓度依赖的方式增加稳态IL - 4R mRNA水平。1,25 (OH)2D3没有改变IL - 4R信息的半衰期，这表明IL - 4R mRNA表达的增加是由于IL - 4R基因转录的增加。综上所述，这些发现提出了IL - 4对矿物质代谢的影响可能是由成骨细胞介导的，这种细胞因子的有效性可能受到维生素D3对IL - 4R表达的影响的影响。
The immune cytokine interleukin 4 has newly recognized effects on skeletal metabolism. While the interaction of many cells ultimately determines bone mass, we have examined the possibility that the osteoblast may be an IL‐4 target in bone by characterizing IL‐4 receptor (IL‐4R) expression by MC3T3‐E1 (MC3T3) murine osteoblastic cells. Based on125I‐IL‐4 binding, MC3T3 cells express large numbers of IL‐4 receptors (125I‐IL‐4 Bmax = 3,000–7,500 sites/cell,125I‐IL‐4 K = 13–40 pM) with an affinity similar to the IL‐4 receptor expressed by an IL‐4–responsive T cell line. Monoclonal anti–IL‐4R antibodies (M1) blocked specific MC3T3125I‐IL‐4 binding and MC3T3 total cell RNA contained full‐length IL‐4R mRNA as detected by reverse transcription DNA amplification utilizing IL‐4R primers and Northern blot analysis. Functionally, IL‐4 treatment of MC3T3 cells resulted in increased cellular proliferation (10–20%) and inhibition of alkaline phosphatase levels (20–40%). While parathyroid hormone (PTH) exposure did not influence IL‐4R levels, vitamin D3treatment augmented MC3T3125I‐IL‐4 binding, in a time‐dependent manner, up to threefold after a 24 h exposure with a metabolite specificity indicating the involvement of the vitamin D receptor. Equilibrium binding studies showed that the impact of 1,25 (OH)2D3on MC3T3125I‐IL‐4 binding was due to an increased IL‐4R Bmax. Cycloheximide treatment inhibited 1,25 (OH)2D3‐‐induced IL‐4R upregulation, suggesting that protein synthesis was required. Furthermore, the steroid increased steady‐state IL‐4R mRNA levels in both a time‐ and concentration‐dependent manner. The IL‐4R message half‐life was not altered by 1,25 (OH)2D3, suggesting that increased IL‐4R mRNA expression resulted from increased IL‐4R gene transcription. Taken together, these findings raise the possibility that IL‐4′s influence on mineral metabolism could be mediated by osteoblasts and that the effectiveness of this cytokine may be influenced by vitamin D3′s impact on IL‐4R expression.