Department of Cellular Differentiation, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan.
Development. 2013 Jun;140(11):2280-8. doi: 10.1242/dev.096354. Epub 2013 Apr 24.
SRY-box containing gene 9 (Sox9) and scleraxis (Scx) regulate cartilage and tendon formation, respectively. Here we report that murine Scx(+)/Sox9(+) progenitors differentiate into chondrocytes and tenocytes/ligamentocytes to form the junction between cartilage and tendon/ligament. Sox9 lineage tracing in the Scx(+) domain revealed that Scx(+) progenitors can be subdivided into two distinct populations with regard to their Sox9 expression history: Scx(+)/Sox9(+) and Scx(+)/Sox9(-) progenitors. Tenocytes are derived from Scx(+)/Sox9(+) and Scx(+)/Sox9(-) progenitors. The closer the tendon is to the cartilaginous primordium, the more tenocytes arise from Scx(+)/Sox9(+) progenitors. Ligamentocytes as well as the annulus fibrosus cells of the intervertebral discs are descendants of Scx(+)/Sox9(+) progenitors. Conditional inactivation of Sox9 in Scx(+)/Sox9(+) cells causes defective formation in the attachment sites of tendons/ligaments into the cartilage, and in the annulus fibrosus of the intervertebral discs. Thus, the Scx(+)/Sox9(+) progenitor pool is a unique multipotent cell population that gives rise to tenocytes, ligamentocytes and chondrocytes for the establishment of the chondro-tendinous/ligamentous junction.
性别决定区 Y 框基因 9（Sox9）和坚韧蛋白（Scx）分别调节软骨和肌腱的形成。在这里，我们报告说，鼠类 Scx（+）/Sox9（+）祖细胞分化为软骨细胞和成纤维细胞/腱细胞，形成软骨和肌腱/韧带之间的连接。Scx（+）区域中的 Sox9 谱系追踪表明，Scx（+）祖细胞可以根据其 Sox9 表达史分为两个不同的群体：Scx（+）/Sox9（+）和 Scx（+）/Sox9（-）祖细胞。成纤维细胞来源于 Scx（+）/Sox9（+）和 Scx（+）/Sox9（-）祖细胞。肌腱越接近软骨原基，就有越多的成纤维细胞来自 Scx（+）/Sox9（+）祖细胞。腱细胞以及椎间盘的纤维环细胞也是 Scx（+）/Sox9（+）祖细胞的后代。Scx（+）/Sox9（+）细胞中 Sox9 的条件性失活导致肌腱/韧带进入软骨的附着部位以及椎间盘的纤维环出现缺陷形成。因此，Scx（+）/Sox9（+）祖细胞池是一种独特的多能细胞群体，可产生成纤维细胞、腱细胞和成软骨细胞，用于建立软骨腱/韧带连接。
