Expression and physiological role of CCN4/Wnt-induced secreted protein 1 mRNA splicing variants in chondrocytes
Expression and physiological role of CCN4/Wnt-induced secreted protein 1 mRNA splicing variants in chondrocytes
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DOI：
10.1111/j.1742-4658.2007.05709.x
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发表时间：
2007-04-01
期刊：
影响因子：
5.4
通讯作者：
Takigawa, Masaharu
中科院分区：
文献类型：
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作者：
Yanagita, Takeshi;Kubota, Satoshi;Takigawa, Masaharu
CCN4/ wnt诱导分泌蛋白1 （WISP1）是CCN （CTGF/Cyr61/Nov）家族蛋白之一。CCN成员具有典型的结构，由四个保守的富含半胱氨酸的模块组成，它们的变体缺乏某些模块，由选择性剪接或基因突变产生，已经在各种病理条件下被描述。先前的一些报告描述了在一些恶性肿瘤中缺乏第二模块的CCN4/WISP1变体（WISP1v），但目前没有关于正常组织中WISP1变体产生的信息。分析了CCN4/WISP1 mRNA及其变体在人软骨肉瘤来源的软骨细胞HCS-2/8和兔生长软骨（RGC）软骨细胞中的表达。首先，我们发现WISP1v和WISP1的一个新变体（WISP1vx）在HCS-2/8中表达，以及全长WISP1 mRNA。这个新变体缺少第二和第三模块的编码区域以及第一个模块的一小部分。为了监测CCN4/WISP1 mRNA在软骨细胞分化过程中的表达，我们对RGC细胞进行培养和取样，直到它们矿化。结果，我们在正常的RGC细胞中发现了一个WISP1v同源基因。有趣的是，随着终末分化，WISP1v mRNA水平显著升高。此外，WISP1v的过表达引发了碱性磷酸酶基因的表达，该基因是HCS-2/8细胞终末分化的标志。这些发现表明，WISP1v在软骨细胞向软骨内成骨的分化中起着关键作用，而hcs -2/8特异性WISP1vx可能与软骨肉瘤的表型转化有关。
CCN4/Wnt-induced secreted protein 1 (WISP1) is one of the CCN (CTGF/Cyr61/Nov) family proteins. CCN members have typical structures composed of four conserved cysteine-rich modules and their variants lacking certain modules, generated by alternative splicing or gene mutations, have been described in various pathological conditions. Several previous reports described a CCN4/WISP1 variant (WISP1v) lacking the second module in a few malignancies, but no information concerning the production of WISP1 variants in normal tissue is currently available. The expression of CCN4/WISP1 mRNA and its variants were analyzed in a human chondrosarcoma-derived chondrocytic cell line, HCS-2/8, and primary rabbit growth cartilage (RGC) chondrocytes. First, we found WISP1v and a novel variant of WISP1 (WISP1vx) to be expressed in HCS-2/8, as well as full-length WISP1 mRNA. This new variant was lacking the coding regions for the second and third modules and a small part of the first module. To monitor the expression of CCN4/WISP1 mRNA along chondrocyte differentiation, RGC cells were cultured and sampled until they were mineralized. As a result, we identified a WISP1v ortholog in normal RGC cells. Interestingly, the WISP1v mRNA level increased dramatically along with terminal differentiation. Furthermore, overexpression of WISP1v provoked expression of an alkaline phosphatase gene that is a marker of terminal differentiation in HCS-2/8 cells. These findings indicate that WISP1v thus plays a critical role in chondrocyte differentiation toward endochondral ossification, whereas HCS-2/8-specific WISP1vx may be associated with the transformed phenotypes of chondrosarcomas.