BACKGROUND:Collagen receptors are characterized by binding to and being activated by collagens. We know little about the molecular mechanism by which the integrins and discoidin domains (DDRs) recognize collagen. OBJECTIVE:The aim of this study was to investigate the expression of two main collagenreceptor subfamilies, integrins and DDRs, during osteogenic and chondrogenic differentiation of human mesenehymal stem cells (hMSCs). METHODS:Using qRT-PCR, Western blots and FACS, the levels of DDR1, DDR2, integrin subunits β1, α1, α2, α10 and α11 receptors on hMSCs, were assessed upon activation by collagen type I, as well as during osteogenic and chondrogenic differentiation. RESULTS:The expression of DDR2 and integrin α11β1 was altered compared with other receptors when the cells were cultured under undifferentiated conditions. During osteogenic and chondrogenetic differentiation, DDR2 and α11 were up-regulated during early stages (6 day) of osteogenesis and chondrogenesis, respectively. The expression and activation of DDR2 was concomitant with another receptor integrin subunit β1 during osteogenetic differentiation. CONCLUSIONS:The results suggested that DDR2 was more specific for osteogenesis than chondrogenesis, while integrin α11β1 was more specific in chondrogenesis. DDR2 and α11 may play a role in the regulation of osteogenesis and chondrogenesis based on the differential expression of these receptors during lineage-dependent changes.

中文翻译：

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人间充质干细胞成骨和软骨分化过程中两个胶原受体亚家族整合素和盘状结构域的表达

背景：胶原蛋白受体的特点是与胶原蛋白结合并被其激活。我们对整合素和盘状结构域 (DDR) 识别胶原蛋白的分子机制知之甚少。目的：本研究的目的是研究两种主要的胶原受体亚家族整合素和 DDR 在人间充质干细胞 (hMSCs) 的成骨和软骨形成分化过程中的表达。方法：使用 qRT-PCR、Western 印迹和 FACS，评估 hMSC 上 DDR1、DDR2、整合素亚基 β1、α1、α2、α10 和 α11 受体在 I 型胶原蛋白激活以及成骨和软骨形成过程中的水平。分化。结果：与其他受体相比，在未分化条件下培养细胞时，DDR2和整合素α11β1的表达发生改变。在成骨和成软骨分化过程中，DDR2 和α11 分别在成骨和软骨形成的早期阶段（6 天）上调。在成骨分化过程中，DDR2 的表达和激活伴随着另一个受体整合素亚基 β1。结论：结果表明，DDR2 对成骨的特异性高于软骨形成，而整合素 α11β1 对软骨形成的特异性更高。基于这些受体在谱系依赖性变化期间的差异表达，DDR2 和 α11 可能在成骨和软骨形成的调节中发挥作用。在成骨分化过程中，DDR2 的表达和激活伴随着另一个受体整合素亚基 β1。结论：结果表明，DDR2 对成骨的特异性高于软骨形成，而整合素 α11β1 对软骨形成的特异性更高。基于这些受体在谱系依赖性变化期间的差异表达，DDR2 和 α11 可能在成骨和软骨形成的调节中发挥作用。在成骨分化过程中，DDR2 的表达和激活伴随着另一个受体整合素亚基 β1。结论：结果表明，DDR2 对成骨的特异性高于软骨形成，而整合素 α11β1 对软骨形成的特异性更高。基于这些受体在谱系依赖性变化期间的差异表达，DDR2 和 α11 可能在成骨和软骨形成的调节中发挥作用。