Increased expression of matrilin-3 not only in osteoarthritic articular cartilage but also in cartilage-forming tumors, and down-regulation of SOX9 via epidermal growth factor domain 1-dependent signaling
Increased expression of matrilin-3 not only in osteoarthritic articular cartilage but also in cartilage-forming tumors, and down-regulation of SOX9 via epidermal growth factor domain 1-dependent signaling
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DOI：
10.1002/art.23761
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发表时间：
2008-09-01
影响因子：
--
通讯作者：
Magdalou, Jacques
中科院分区：
文献类型：
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作者：
Vincourt, Jean-Baptiste;Vignaud, Jean-Michel;Magdalou, Jacques
目标。通过将其在人类常规软骨性肿瘤与关节软骨肿瘤中的差异表达进行比较，确定软骨表型的调节因子。差异蛋白质组学分析显示，MATN3是软骨表型的候选调节因子。通过细胞培养分离、逆转录聚合酶链反应和Western blot分析，研究了其在人HCS-2/8软骨肉瘤细胞和转染的软骨细胞中调节基因表达的能力。软骨特异性基质蛋白MATN3在软骨瘤和常规软骨肉瘤中表达增加。免疫组织化学表明，肿瘤细胞的细胞质结构中发现了相当一部分MATN3。对细胞内MATN3的分析显示，在HCS-2/8人软骨肉瘤细胞和转染的人软骨细胞中，它都对应于一种不完全成熟的MATN3多肽。适度增加MATN3的表达导致其在细胞内滞留。在HCS-2/8细胞培养中，抗体介导的可溶性细胞外MATN3阻断导致MATN3和软骨生成转录因子SOX9的表达增加。相反，MATN3异位表达的增加导致原代软骨细胞中MATN3和SOX9的表达降低，而缺乏其第一表皮生长因子（EGF）样结构域的突变MATN3未能下调SOX9。MATN3的异常表达和加工是常规软骨肿瘤的特征。MATN3成熟的一个特殊步骤限制了其通过分泌机制的加工，导致其在表达增加时在细胞内积累。然而，可溶性分泌的MATN3在信使RNA和蛋白水平上下调SOX9。MATN3的第一个egf样结构域是其对SOX9调控活性的关键决定因素。这些MATN3的活性提示其在骨关节炎中的表达增加可能有助于关节软骨的退变。
Objective. To identify regulators of the cartilaginous phenotype, on the basis of their differential expression in human conventional chondrogenic tumors compared with articular cartilage.Methods. Differential proteomics analysis revealed matrilin-3 (MATN3) as a candidate regulator of the cartilaginous phenotype. Its capacity to modulate gene expression was investigated in human HCS-2/8 chondrosarcoma cells and transfected chondrocytes, using cell culture fractionation, reverse transcription-polymerase chain reaction, and Western blot analyses.Results. Increased expression of the cartilage-specific matrix protein MATN3 was specifically observed in enchondromas and conventional chondrosarcomas. A substantial fraction of MATN3 was found in cytoplasmic structures of tumor cells, as demonstrated by immunohistochemistry. Analyses of intracellular MATN3 revealed that it corresponded to an imperfectly maturated MATN3 polypeptide, both in HCS-2/8 human chondrosarcoma cells and in transfected human chondrocytes. Moderately increased expression of MATN3 resulted in its intracellular retention. Antibody-mediated blockade of soluble, extracellular MATN3 in HCS-2/8 cell cultures resulted in increased expression of MATN3 and the chondrogenic transcription factor SOX9. Conversely, increased ectopic expression of MATN3 resulted in decreased expression of MATN3 and SOX9 in primary chondrocytes, while a mutant MATN3 lacking its first epidermal growth factor (EGF)-like domain failed to down-regulate SOX9.Conclusion. Aberrant expression and processing of MATN3 are hallmarks of conventional cartilaginous neoplasms. A particular step in the maturation of MATN3 limits its processing through the secretion machinery, resulting in its intracellular accumulation upon increased expression. Soluble, secreted MATN3, however, down-regulates SOX9 at the messenger RNA and protein levels. The first EGF-like domain of MATN3 is a critical determinant of its regulatory activity toward SOX9. These activities of MATN3 suggest that its increased expression in osteoarthritis might contribute to the degeneration of articular cartilage.