Repair and regeneration in a novel animal model

描述（由申请人提供）：再生医学和组织工程已经成为一些最有吸引力的领域，具有潜在的高临床应用。如果一个成年人不幸失去了手指或肢体，伤口愈合后没有再生的迹象。在羊膜动物中，一些蜥蜴在截肢后表现出非凡的尾巴再生能力。在这里，我们建议开发这种独特的体内再生模型，以了解修复和再生背后独特的分子/细胞机制。长期目标是学习动物如何在自然界中完成这个过程，并能够将这些原则应用于人类截肢（例如肢体，手指）后的再生和生物工程。有助于提高我们对生理和病理现象的理解的理想动物模型的例子包括果蝇、秀丽隐杆线虫等。爬行动物中有一种独特的现象是“自切”，即受到压力的蜥蜴会自动在特定的断裂平面上折断尾巴。然后从这些层面开始再生。由于这成为“生理”过程的一部分，我们假设干细胞可能存在于位于断裂面附近的壁龛中，类似于毛发蜕皮周期中的凸起干细胞。另外，伤口中的细胞也可能经历去分化以产生多能胚基。在任何一种情况下，再生都被启动，组织形态发生的进展超出了简单的修复。为了测试这些可能性，我们将追求以下目标。1)描述爬行动物尾部损伤后的再生事件，包括细胞增殖、凋亡和迁移。2)定位再生爬行动物尾巴中前体细胞的起源，包括使用长期标签保留和染色质状态标记。3)爬行动物尾巴再生过程中涉及哪些分子事件？与发育相关的信号分子通路（如Msx、β - catenin、Shh、BMP、FGF等）将优先用于制图研究。可能的候选物将使用siRNA的电穿孔进行干扰。

DESCRIPTION (provided by applicant): Regenerative medicine and tissue engineering have emerged as some of the most fascinating fields with potentially high clinical applications. If an adult human unfortunately loses a digit or limb, the wounds heal without signs of regeneration. Among amniotes, some lizards show a remarkable ability to regenerate tails following amputation. Here we propose to develop this unique in vivo model of regeneration to understand the unique molecular/ cellular mechanisms underlying repair and regeneration. The long term goal is to learn how animals do this process in Nature and to be able to apply these principles to benefit regeneration and bio-engineering following human amputation (e.g., limb, digit). Examples of ideal animal models that helped to improve our understanding of physiological and pathological phenomena include the use of Drosophila, C. elegans, etc. A unique phenomenon in reptiles is "autotomy" in which the stressed lizards automatically break their tails at specific fracture planes. Regeneration then initiates from these planes. Since this becomes part of the "physiological" process, we hypothesize that stem cells may reside in niches located near the facture plane, similar to bulge stem cells in hair molting cycles. Alternatively, cells in wounds may undergo de- differentiation to generate pluri-potential blastema. In either case, the regeneration is initiated and tissue morphogenesis progresses beyond simple repair. To test for these possibilities, we will pursue the following aims. 1) Characterize the regenerative events following wounding of reptile tails, including cell proliferation, apoptosis and migration. 2) Locate the origin of precursor cells in regenerating reptile tails, including the use of long-term label retention and chromatin status markers. 3) What molecular events are involved during reptile tail regeneration? Development related signaling molecule pathways (e.g., Msx, beta catenin, Shh, BMP, FGF, etc.) will be prioritized for mapping studies. Likely candidates will be perturbed using electroporation of siRNA.