Identification and functional characterization of two type VI collagen receptors, alpha 3 beta 1 integrin and NG2, during avian corneal stromal development.
Identification and functional characterization of two type VI collagen receptors, alpha 3 beta 1 integrin and NG2, during avian corneal stromal development.
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发表时间：
1998-02
影响因子：
4.4
通讯作者：
Kathleen J. Doane;Scott J. Howell;David E. Birk
中科院分区：
文献类型：
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作者：
Kathleen J. Doane;Scott J. Howell;David E. Birk
角膜基质中细胞外基质结构的形成和维持与丰富的VI型胶原沉积有关。这种胶原蛋白涉及介导细胞-基质和基质-基质相互作用。虽然角膜成纤维细胞广泛分布在这种胶原蛋白上，但其在角膜发育中的作用尚未阐明。方法为了阐明这种胶原的作用，两种VI型胶原受体在角膜发育过程中使用免疫化学技术进行了研究：α 3 β 1整合素和一个完整的膜蛋白聚糖，NG 2。结果：在胚胎第6天，这些受体以弥散的方式存在于角膜和前角膜区域的细胞上，表明具有迁移表型。在胚胎第14天，当基质完全分化时，α 3和NG 2以点状模式定位于角膜成纤维细胞的子集上，而β 1更普遍地表达。NG 2和VI型胶原蛋白的共定位表明，这种胶原蛋白是存在的，其组织中的点状与NG 2阳性细胞相关。在胚胎第5和14天的免疫化学分析显示，α 3和β 1在155 kDa和120 kDa，分别，并证明这些亚基相互作用，形成异二聚体。NG 2存在330 kDa的核心蛋白和约600 kDa的完整蛋白多糖，基质裂解物分析表明含有硫酸软骨素的蛋白多糖。基质-受体交联证实了眼周间充质细胞和角膜成纤维细胞中β 1和NG 2与VI型胶原蛋白的相互作用，而只有一部分细胞表达α 3，表明存在另一种β 1整联蛋白。没有观察到α 3 β 1或NG 2的体内和体外表达之间的变化。结论：这些数据表明，两种VI型胶原受体，α 3 β 1和NG 2，存在于角膜基质发育过程中，这些受体与VI型胶原的功能相互作用。这些相互作用可能在角膜细胞迁移、发育和维持角膜结构中起作用。
PURPOSE The development and maintenance of extracellular matrix architecture in the corneal stroma is associated with abundant type VI collagen deposition. This collagen has been implicated in mediating both cell-matrix and matrix-matrix interactions. Although corneal fibroblasts spread extensively on this collagen, its role in corneal development has not been elucidated. METHODS To clarify the role of this collagen, two type VI collagen receptors were studied during corneal development using immunochemical techniques: alpha 3 beta 1 integrin and an integral membrane proteoglycan, NG2. RESULTS At embryonic day 6, these receptors were present in a diffuse pattern on cells within the cornea and juxtacorneal regions, indicating a migratory phenotype. At embryonic day 14, when the stroma is fully differentiated, alpha 3 and NG2 were localized in a punctate pattern on a subset of corneal fibroblasts, whereas beta 1 was more ubiquitously expressed. Colocalization of NG2 and type VI collagen indicated that this collagen was present and punctate in its organization was associated with NG2-positive cells. Immunochemical analyses at embryonic days 5 and 14 revealed alpha 3 and beta 1 at 155 kDa and 120 kDa, respectively, and demonstrated that these subunits were interacting to form a heterodimer. NG2 was present with a core protein of 330 kDa and an intact proteoglycan of approximately 600 kDa, and analysis of stromal lysates indicated a chondroitin sulfate-containing proteoglycan. Matrix-receptor cross-linking demonstrated the interaction of beta 1 and NG2 in periocular mesenchyme cells and corneal fibroblasts with type VI collagen, whereas only a subset of cells expressed alpha 3, indicating the presence of another beta 1 integrin. No variations between in vivo and in vitro expression of either alpha 3 beta 1 or NG2 were observed. CONCLUSIONS These data indicate that two receptors for type VI collagen, alpha 3 beta 1 and NG2, are present during corneal stromal development, with a functional interaction of these receptors with type VI collagen. These interactions may play a role in corneal cell migration, development, and maintenance of corneal architecture.