cAMP Activation by PACAP/VIP Stimulates IL-6 Release and Inhibits Osteoblastic Differentiation Through VPAC2 Receptor in Osteoblastic MC3T3 Cells
cAMP Activation by PACAP/VIP Stimulates IL-6 Release and Inhibits Osteoblastic Differentiation Through VPAC2 Receptor in Osteoblastic MC3T3 Cells
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DOI：
10.1002/jcp.21831
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发表时间：
2009-10-01
影响因子：
5.6
通讯作者：
Tatsuno, Ichiro
中科院分区：
文献类型：
--
作者：
Nagata, Azusa;Tanaka, Tomoaki;Tatsuno, Ichiro
神经肽垂体腺苷酸环化酶激活多肽（PACAP）是胰高血糖素/血管活性肠肽（VIP）超家族的成员，刺激环AMP积累，引发多种生物过程，例如：神经营养作用、免疫和垂体功能、学习和记忆、儿茶酚胺生物合成和心肺功能调节。破骨细胞和成骨细胞均表达PACAP/VIP受体，这与它们在骨代谢中的作用有关。为了进一步了解PACAP/VIP家族在调控骨代谢中的作用，我们研究了小鼠颅骨成骨细胞系MC 3 T3-E1的分化模型。定量RT-PCR分析表明，MC 3 T3-E1细胞只表达VPAC 2受体，其表达在成骨细胞分化过程中上调，而VPAC 1和PAC 1受体不表达。与受体亚型的表达一致，PACAP和VIP都以时间和剂量依赖性的方式刺激cAMP积累，在未分化和分化细胞中具有相似的效力，而PAC 1-R的特异性激动剂Maxadilan则没有。siRNA下调VPAC 2-R的表达可完全阻断PACAP和VIP介导的cAMP反应。重要的是，PACAP/VIP以及forskolin显著抑制分化后碱性磷酸酶mRNA的诱导，并且用cAMP抑制剂2 '，5'-二脱氧腺苷预处理，恢复了PACAP的抑制作用。我们还发现，PACAP和VIP刺激IL-6的释放，骨吸收的刺激剂，和VPAC 2-R沉默抑制IL-6的生产。因此，PACAP/VIP可以激活腺苷酸环化酶反应，并通过VPAC 2受体调节IL-6的释放，从而抑制MC 3 T3-E1细胞中的成骨细胞分化。J.细胞。221：75-83，2009. (C)2009威利-利斯公司
The neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP), a member of the glucagon/vasoactive intestinal peptide (VIP) superfamily, stimulates cyclic AMP accumulation initiating a variety of biological processes such as: neurotropic actions, immune and pituitary function, learning and memory, catecholamine biosynthesis and regulation of cardiopulmonary function. Both osteoclasts and osteoblasts have been shown to express receptors for PACAP/VIP implicated in their role in bone metabolism. To further understand the role of PACAP/VIP family in controlling bone metabolism, we investigated differentiation model of MC3T3-E1 cells, an osteoblastic cell line derived from mouse calvaria. Quantitative RT-PCR analysis demonstrated that MC3T3-E1 cells expressed only VPAC2 receptor and its expression was upregulated during osteoblastic differentiation, whereas VPAC1 and PAC1 receptors were not expressed. Consistent with expression of receptor subtype, both PACAP and VIP stimulate cAMP accumulation in a time- and dose-dependent manner with the similar potency in undifferentiated and differentiated cells, while Maxadilan, a specific agonist for PAC1-R,did not. Furthermore, downregulation of VPAC2-R by siRNA completely blocked cAMP response mediated by PACAP and VIP. Importantly, PACAP/VIP as well as forskolin markedly suppressed the induction of alkaline phosphatase mRNA upon differentiation and the pretreatment with 2',5'-dideoxyadenosine, a cAMP inhibitor, restored its inhibitory effect of PACAP. We also found that PACAP and VIP stimulated IL-6 release, a stimulator of bone resorption, and VPAC2-R silencing inhibited IL-6 production. Thus, PACAP/VIP can activate adenylate cyclase response and regulate IL-6 release through VPAC2 receptor with profound functional consequences for the inhibition of osteoblastic differentiation in MC3T3-E1 cells. J. Cell. Physiol. 221: 75-83, 2009. (C) 2009 Wiley-Liss, Inc.