Alpha1-adrenergic receptor stimulation induces the expression of receptor activator of nuclear factor kappaB ligand gene via protein kinase C and extracellular signal-regulated kinase pathways in MC3T3-E1 osteoblast-like cells.
Alpha1-adrenergic receptor stimulation induces the expression of receptor activator of nuclear factor kappaB ligand gene via protein kinase C and extracellular signal-regulated kinase pathways in MC3T3-E1 osteoblast-like cells.
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发表时间：
2007
影响因子：
3
通讯作者：
T. Nishiura;K. Abe
中科院分区：
文献类型：
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作者：
T. Nishiura;K. Abe
骨髓基质/成骨细胞产生的核因子 kappaB 配体 (RANKL) 受体激活剂是破骨细胞生成和骨吸收的重要调节剂。已证明成骨细胞表达α(1)-肾上腺素能受体。目的 本研究的目的是检验α(1)-肾上腺素能受体刺激通过蛋白激酶C (PKC) 和细胞外信号调节激酶(ERK) 通路诱导成骨细胞中RANKL 基因表达的假设。设计分别通过半定量RT-PCR和蛋白质印迹分析小鼠MC3T3-E1成骨细胞样细胞中RANKL的稳态mRNA水平和ERK的激活。结果 在三种α(1)-肾上腺素能受体亚型mRNA中，α(1b)-和α(1d)-亚型在MC3T3-E1细胞中表达。去氧肾上腺素（α(1)-激动剂）以时间和剂量依赖性方式增加 RANKL 的 mRNA 水平。哌唑嗪（α(1)-拮抗剂）抑制去氧肾上腺素诱导的 RANKL mRNA 表达，但育亨宾（α(2)-拮抗剂）和普萘洛尔（β-拮抗剂）则不然。佛波醇 12-肉豆蔻酸酯 13-乙酸酯（PMA，PKC 激活剂）增加 RANKL mRNA 表达，GF109203X（PKC 抑制剂）抑制去氧肾上腺素诱导的 RANKL mRNA 表达。去氧肾上腺素和 PMA 均刺激 ERK 磷酸化，而哌唑嗪和 GF109203X 均抑制去氧肾上腺素诱导的 ERK 激活。用PD98059（ERK激酶抑制剂）预处理可抑制MC3T3-E1细胞中去氧肾上腺素诱导的ERK磷酸化和RANKL基因表达。结论 这些结果表明，成骨细胞中表达α(1b)-和α(1d)-肾上腺素能受体亚型基因，并且RANKL mRNA的表达可能受到α(1)-肾上腺素能受体刺激的调节。通过激活 α(1)-肾上腺素能受体诱导 RANKL mRNA 可能是通过成骨细胞中的 PKC 和 ERK 信号通路介导的。
UNLABELLED The receptor activator of nuclear factor kappaB ligand (RANKL) produced by bone marrow stromal/osteoblast cells is a crucial regulator of osteoclastgenesis and bone resorption. Osteoblastic cells have been demonstrated to express alpha(1)-adrenergic receptors. OBJECTIVE The purpose of this study was to test the hypothesis that alpha(1)-adrenergic receptor stimulation induces the expression of RANKL gene via protein kinase C (PKC) and extracellular signal-regulated kinase (ERK) pathways in osteoblastic cells. DESIGN The steady-state mRNA levels of RANKL and activation of ERK in mouse MC3T3-E1 osteoblast-like cells were analyzed by semi-quantitative RT-PCR and Western blotting, respectively. RESULTS In three alpha(1)-adrenergic receptor subtype mRNAs, alpha(1b)- and alpha(1d)-subtypes were expressed in MC3T3-E1 cells. The mRNA levels of RANKL were increased by phenylephrine (alpha(1)-agonist) in time- and dose-dependent manners. Prazosin (alpha(1)-antagonist) suppressed the phenylephrine-induced RANKL mRNA expression, but yohimbine (alpha(2)-antagonist) and propranolol (beta-antagonist) did not. Phorbol 12-myristate 13-acetate (PMA, PKC activator) increased RANKL mRNA expression and GF109203X (PKC inhibitor) suppressed the phenylephrine-induced RANKL mRNA expression. Both phenylephrine and PMA stimulated the phosphorylation of ERK, while both prazosin and GF109203X inhibited phenylephrine-induced ERK activation. Pretreatment with PD98059 (ERK kinase inhibitor) inhibited both the phosphorylation of ERK and the expression of RANKL gene induced by phenylephrine in MC3T3-E1 cells. CONCLUSION These results show that alpha(1b)- and alpha(1d)-adrenergic receptor subtype genes are expressed and the expression of RANKL mRNA may be regulated by alpha(1)-adrenergic receptor stimulation in osteoblastic cells. The induction of RANKL mRNA by activating the alpha(1)-adrenergic receptor is probably mediated via PKC and ERK signalling pathways in osteoblastic cells.