Okayama University, Research Core for Interdisciplinary Sciences (RCIS), Kitaku, Okayama, Japan.
Dev Growth Differ. 2010 May;52(4):343-50. doi: 10.1111/j.1440-169X.2009.01165.x. Epub 2010 Feb 10.
The accessory limb model has become an alternative model for performing investigations of limb regeneration in an amputated limb. In the accessory limb model, a complete patterned limb can be induced as a result of an interaction between the wound epithelium, a nerve and dermal fibroblasts in the skin. Studies should therefore focus on examining these tissues. To date, however, a study of cellular contributions in the accessory limb model has not been reported. By using green fluorescent protein (GFP) transgenic axolotl tissues, we can trace cell fate at the tissue level. Therefore, in the present study, we transgrafted GFP skin onto the limb of a non-GFP host and induced an accessory limb to investigate cellular contributions. Previous studies of cell contribution to amputation-induced blastemas have demonstrated that dermal cells are the progenitors of many of the early blastema cells, and that these cells contribute to regeneration of the connective tissues, including cartilage. In the present study, we have determined that this same population of progenitor cells responds to signaling from the nerve and wound epithelium in the absence of limb amputation to form an ectopic blastema and regenerate the connective tissues of an ectopic limb. Blastema cells from dermal fibroblasts, however, did not differentiate into either muscle or neural cells, and we conclude that dermal fibroblasts are dedifferentiated along its developmental lineage.
附肢模型已成为研究断肢肢体再生的替代模型。在附肢模型中，由于伤口上皮、神经和皮肤成纤维细胞之间的相互作用，可以诱导形成完整的图案化肢体。因此，研究应集中在检查这些组织上。然而，迄今为止，尚未有关于附肢模型中细胞贡献的研究报告。通过使用绿色荧光蛋白 (GFP) 转基因蝾螈组织，我们可以在组织水平上追踪细胞命运。因此，在本研究中，我们将 GFP 皮肤移植到非 GFP 宿主的肢体上，并诱导形成附肢，以研究细胞贡献。先前对细胞对截肢诱导的芽基的贡献的研究表明，真皮细胞是许多早期芽基细胞的祖细胞，这些细胞有助于结缔组织的再生，包括软骨。在本研究中，我们已经确定，同一祖细胞群对来自神经和伤口上皮的信号做出反应，在没有肢体截肢的情况下形成异位芽基，并再生异位肢体的结缔组织。然而，真皮成纤维细胞来源的芽基细胞不会分化为肌肉或神经细胞，我们得出结论，真皮成纤维细胞沿着其发育谱系去分化。
