A novel in vitro culture system for analysis of functional role of phosphate transport in endochondral ossification
A novel in vitro culture system for analysis of functional role of phosphate transport in endochondral ossification
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DOI：
10.1016/s8756-3282(00)00302-1
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发表时间：
2000-07-01
期刊：
影响因子：
4.1
通讯作者：
Caverzasio, J
中科院分区：
文献类型：
--
作者：
Guicheux, J;Palmer, G;Caverzasio, J
在软骨内骨化过程中III型钠依赖性磷酸盐转运蛋白（NaPiT）Glvr-1的体内表达表明无机磷酸盐（Pi）转运在软骨钙化中的功能作用。为了进一步分析这种关系，需要一个体外模型的软骨内骨化。在这种情况下，我们研究了新的软骨细胞系ATDC 5中与细胞外基质（ECM）形成和矿化有关的Pi转运的特征，ATDC-5细胞和分离的基质囊泡（MV）中的Pi摄取是由具有III型Pi载体的pH依赖性特征（碱性pH下活性较低）的Na依赖性Pi转运蛋白介导的。北方印迹分析表明ATDC-5细胞在其成熟的各个阶段表达Glvr-1转录本，在增殖期表达最高。在孤立的MV中，Pi转运活性在第21天达到最大，伴随着X型胶原信使RNA表达的开始。这些事件发生在基质矿化开始之前，这在第25天是明显的，然后逐渐增加，直到第47天。MV中最大Pi转运活性与矿化软骨细胞标记物表达之间的这种时间关系与ATDC-5细胞培养物中观察到的ECM钙化中Pi转运的可能参与是相容的。总之，这些观察结果表明，ATCD-5细胞培养代表了一个有前途的模型，用于分析的功能作用的Pi运输的初始事件endochondrialossification。(Bone 27：69-74; 2000）（C）Elsevier Science Inc. All rights reserved.
In vivo expression of the type III sodium-dependent phosphate transporter (NaPiT) Glvr-1 during endochondral ossification, suggests a functional role for inorganic phosphate (Pi) transport in cartilage calcification. For further analysis of this relationship, an in vitro model of endochondral ossification is required. In this context, we investigated the characteristics of Pi transport in the new chondrogenic cell line ATDC5 in relation to extracellular matrix (ECM) formation and mineralization, Pi uptake in ATDC-5 cells and in isolated matrix vesicles (MVs) is mediated by an Na-dependent Pi transporter with a pH dependency characteristic of a type III Pi carrier (lower activity at alkaline pH). Northern blot analysis indicated that ATDC-5 cells express Glvr-1 transcripts during the various stages of their maturation with a maximal level during the proliferating stage. In isolated MVs, Pi transport activity was maximal at day 21, concomitant with the beginning of type X collagen messenger RNA expression. These events preceded the initiation of matrix mineralization, which was apparent at day 25, and then gradually increased until day 47, This temporal relationship between maximal Pi transport activity in MVs and the expression of a marker of mineralizing chondrocytes is compatible with the possible involvement of Pi transport in the ECM calcification observed in ATDC-5 cell cultures. In conclusion, these observations suggest that ATCD-5 cells in culture represent a promising model for the analysis of a functional role of Pi transport in the initial events of endochondral ossification. (Bone 27:69-74; 2000) (C) 2000 by Elsevier Science Inc. All rights reserved.