Bavin Emma P, Atkinson Francesca, Barsby Tom, Guest Debbie J
1 Centre for Preventive Medicine , Animal Health Trust, Newmarket, United Kingdom .
Stem Cells Dev. 2017 Mar 15;26(6):441-450. doi: 10.1089/scd.2016.0279. Epub 2017 Jan 24.
The transcription factor scleraxis is required for tendon development and is upregulated during embryonic stem cell (ESC) differentiation into tenocytes. However, its role beyond early embryonic development is not defined. We utilized a short hairpin RNA to knock down scleraxis expression in ESCs and adult and fetal tenocytes. No effect on growth or morphology was observed in two-dimensional cultures. However, scleraxis knockdown in fetal tenocytes significantly reduced COL1A1, COMP, and SOX9 gene expression. Scleraxis knockdown in adult tenocytes had no effect on the expression of these genes. Strikingly, differentiating ESCs and fetal tenocytes without scleraxis failed to reorganize a three-dimensional (3D) matrix and generate artificial tendons. This was associated with a significantly reduced survival. In contrast, there was no effect on the survival and remodeling capacity of adult tenocytes following scleraxis knockdown. Overexpression of scleraxis in fetal tenocytes rescued gene expression, cell survival in 3D, and subsequent matrix contraction. Together, these results demonstrate that scleraxis is not only essential for ESC differentiation into tenocytes but that it also has an active role in maintaining fetal tenocytes, which is then redundant in adult tenocytes.
转录因子硬骨素是肌腱发育所必需的，并且在胚胎干细胞（ESC）分化为肌腱细胞的过程中上调。然而，其在早期胚胎发育之外的作用尚未明确。我们利用短发夹RNA敲低ESC以及成年和胎儿肌腱细胞中硬骨素的表达。在二维培养中未观察到对生长或形态的影响。然而，胎儿肌腱细胞中硬骨素的敲低显著降低了COL1A1、COMP和SOX9基因的表达。成年肌腱细胞中硬骨素的敲低对这些基因的表达没有影响。令人惊讶的是，缺乏硬骨素的分化ESC和胎儿肌腱细胞无法重组三维（3D）基质并生成人工肌腱。这与存活率显著降低有关。相比之下，硬骨素敲低后对成年肌腱细胞的存活和重塑能力没有影响。胎儿肌腱细胞中硬骨素的过表达挽救了基因表达、3D中的细胞存活以及随后的基质收缩。总之，这些结果表明硬骨素不仅对ESC分化为肌腱细胞至关重要，而且在维持胎儿肌腱细胞方面具有积极作用，而在成年肌腱细胞中则是多余的。
