Differential roles of CCN family proteins during osteoblast differentiation: Involvement of Smad and MAPK signaling pathways
Differential roles of CCN family proteins during osteoblast differentiation: Involvement of Smad and MAPK signaling pathways
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DOI：
10.1016/j.bone.2011.06.033
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发表时间：
2011-11-01
期刊：
影响因子：
4.1
通讯作者：
Takigawa, Masaharu
中科院分区：
文献类型：
--
作者：
Kawaki, Harumi;Kubota, Satoshi;Takigawa, Masaharu
CCN家族蛋白在细胞过程的许多方面发挥不同的作用，如增殖、分化、粘附、迁移、血管生成和存活。在脊椎动物的骨组织中，大多数CCN家族成员在成骨细胞中表达。然而，它们的空间和时间分布，以及它们的功能，仍然只是部分了解。在这项研究中，我们评估了CCN家族成员在体内骨骼组织中的定位，并比较分析了原代培养的小鼠成骨细胞中成员的基因表达模式和功能。免疫荧光分析显示，CCN家族成员的差异产生于成骨细胞和骨细胞。在这些成骨细胞中证实了所有Ccn转录物的存在。其中CCN 1、CCN 2、CCN 4和CCN 5在骨细胞中发现。CCN 4和CCN 5也分布于骨基质内的骨细胞中。接下来，我们研究了成骨细胞分化过程中Ccn家族成员的表达模式。沿着分化，大多数成员遵循适当的基因表达模式：而Ccn 4和Ccn 5显示出非常相似的模式。此外，我们还利用重组CCN蛋白和RNA干扰技术研究了CCN家族成员对成骨细胞活性的影响。该家族的五个成员对成骨细胞增殖或分化具有积极作用。值得注意的是，CCN 3显著抑制成骨细胞活性。每种Ccn特异性siRNA可以通过观察到的相应重组CCN蛋白的作用预期的方式调节成骨细胞活性。此外，我们还发现细胞外信号调节激酶1/2和p38丝裂原活化蛋白激酶途径在CCN家族成员介导的成骨细胞活性修饰中起着关键作用，总的来说，所有CCN家族成员都被发现沿着分化而差异表达，因此可以参与成骨细胞谱系的进展。(C)2011 Elsevier Inc. All rights reserved.
CCN family proteins play diverse roles in many aspects of cellular processes such as proliferation, differentiation, adhesion, migration, angiogenesis and survival. In the bone tissue of vertebrate species, the expression of most CCN family members has been observed in osteoblasts. However, their spatial and temporal distributions, as well as their functions, are still only partially understood. In this study, we evaluated the localization of CCN family members in skeletal tissue in vivo and comparatively analyzed the gene expression patterns and functions of the members in murine osteoblasts in primary culture. Immunofluorescent analyses revealed that the CCN family members were differentially produced in osteoblasts and osteocytes. The presence of all Ccn transcripts was confirmed in those osteoblasts. Among the members, CCN1, CCN2, CCN4 and CCN5 were found in osteocytes. CCN4 and CCN5 were distributed in osteocytes located inside of bone matrix as well. Next, we investigated the expression pattern of Ccn family members during osteoblast differentiation. Along with differentiation, most of the members followed proper gene expression patterns: whereas, Ccn4 and Ccn5 showed quite similar patterns. Furthermore, we evaluated the effects of CCN family members on the osteoblastic activities by using recombinant CCN proteins and RNA interference method. Five members of this family displayed positive effects on osteoblast proliferation or differentiation. Of note, CCN3 drastically inhibited the osteoblast activities. Each Ccn specific siRNA could modulate osteoblast activities in a manner expected by the observed effect of respective recombinant CCN protein. In addition, we found that extracellular signal-regulated kinase1/2 and p38 mitogen-activated protein kinase pathways were critically involved in the CCN family member-mediated modification of osteoblast activities.Collectively, all Ccn family members were found to be differentially expressed along with differentiation and therefore could participate in progression of the osteoblast lineage. (C) 2011 Elsevier Inc. All rights reserved.