Why Don’t Lizards Regenerate Perfect Tails Like Salamanders?

为什么蜥蜴不能像火蜥蜴那样再生出完美的尾巴？

基本信息

批准号：
9256525
负责人：
Thomas Peter Lozito
金额：
$ 29.11万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-05-01 至 2021-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9256525
关键词：
Amaze Ambystoma Anatomy Animal Model Animals Area Calcified Cartilage Cell Differentiation process Cell Line Cell Proliferation Cell Transplantation Cells Characteristics Chondrocytes Complex Development Dorsal Employee Strikes Environment Erinaceidae Exhibits Female Genetic Engineering Goals Human Immunosuppression Individual Intervention Intervertebral disc structure Knowledge Lead Length Lizards Mammals Medicine Molecular Natural regeneration Neural tube Operative Surgical Procedures Organism Outcome Patients Pattern Pattern Formation Periosteal Cell Phenocopy Population Process Proliferating Regenerative Medicine Role Salamander Signal Transduction Skeletal Development Skeleton Spinal Cord Stem cells Tail Tissue Transplantation Tissues Translating Tube Vertebral column asexual base calcification cartilaginous comparative design experience experimental study genome editing healing implantation improved in vivo information model innovation insight knowledge base nerve stem cell offspring public health relevance regenerative repaired retinal rods skeletal skeletal regeneration smoothened signaling pathway stem cell differentiation stem cell population tissue regeneration transcriptomics vertebra body

项目摘要

DESCRIPTION (provided by applicant): Enhancing regenerative capacities is a fundamental goal in medicine. As yet, the principles of salamander regeneration to augment mammalian healing are not directly applicable. Here we propose using lizards, more closely related to mammals yet exhibiting remarkable regenerative capabilities, as a model organism in a set of studies aimed at manipulating skeletal regeneration capacities. While both salamanders and lizards regenerate their tails, the former regenerate a near-perfect copy of the original tail, whie the latter is known as an "imperfect replicate" with several key anatomical differences compared to the original tail, most striking of which concerns the regenerated tail skeleton. Our recent comparative analyses of regenerated tail development have identified 3 main differences related to (1) dorsoventral patterning signals, (2) stem cell populations, and (3) segmentation signals. During skeletal regeneration, salamanders form a cartilage rod (CR) ventral to the tail axis, whereas the regenerated lizard tail lacks dorsoventral skeletal patterning and forms a cartilage tube (CT). Our initial findings suggest that the regenerated spinal cord is responsible for cartilage patterning in both salamander and lizard tails. The salamander spinal cord produces factors that both inhibit and induce cartilage formation, while the lizard spinal cord produces cartilage inductive factors only; furthermore, they differ in their neural stem cell populations. Salamander stem cells are able to differentiate into both dorsal and ventral lineages, while lizard stem cells differentiate into ventral lineages only. Once formed, the salamander CR undergoes segmentation marked by new cartilage formed at distinct regions by populations of proliferating chondrocytes and periosteal cells. These regions are not detectable in the lizard CT, which does not segment, likely due to lack of molecular proliferative signals. We hypothesize that these differences in pattern formation and regulatory networks underlie the divergent regenerative outcomes between lizards and salamanders. Based on this comparative analysis, we hypothesize the feasibility of mechanistically based intervention to shift the "imperfectly" regenerating lizard tail to phenocopy the "perfectly" regenerating salamander tail. The Aims are: (1) Manipulate the dorsoventral signals present in regenerating salamander tails but absent in lizard tails; (2) Introduce stem cell populations found in salamander but not lizard tails; and (3) Determine and manipulate the proliferative signals in regenerating salamander tails that are absent in lizard tails. An integrated approach is proposed, incorporating transcriptomics, CRIPSR/Cas9 genome editing of lizard stem cells, molecular and cellular analyses, in vivo surgical manipulations, and delivery of cell and bioactive agents. We believe that this approach will produce the first lizard tails with skeletons exhibiting patterning and segmentation that phenocopy regenerated salamander tails. These studies will contribute towards mechanistic understanding of a vertebrate regenerative process, and may lead to improving healing in non-regenerative organisms, including humans, specifically related to skeletal development and repair.

描述（由申请人提供）：增强再生能力是医学的一个基本目标，迄今为止，蝾螈再生增强哺乳动物愈合的原理并不直接适用，这里我们建议使用与哺乳动物关系更密切但具有显着再生能力的蜥蜴。作为一系列旨在操纵骨骼再生能力的研究中的模型生物，蝾螈和蜥蜴都会再生尾巴，而前者会再生尾巴。原始尾巴的近乎完美的复制品，被称为“不完美的复制品”，与原始尾巴相比，有几个关键的解剖学差异，其中最引人注目的是我们最近对再生尾巴发育的比较分析。确定了与（1）背腹模式信号、（2）干细胞群和（3）分割信号相关的 3 个主要差异。在骨骼再生过程中，蝾螈在尾部腹侧形成软骨杆（CR）。轴，而再生的蜥蜴尾巴缺乏背腹骨骼图案并形成软骨管（CT），我们的初步研究结果表明，再生的脊髓负责蝾螈和蜥蜴尾巴的软骨图案。蝾螈脊髓产生抑制两者的因子。并诱导软骨形成，而蜥蜴脊髓仅产生软骨诱导因子；此外，它们的神经干细胞群不同。能够分化成背侧和腹侧谱系，而蜥蜴干细胞仅分化为腹侧谱系。蝾螈CR一旦形成，就会经历由增殖的软骨细胞和骨膜细胞群在不同区域形成的新软骨的分割，这些区域在蜥蜴CT中无法检测到，这可能是由于蜥蜴CT不分割。我们发现，模式形成和调控网络的这些差异是蜥蜴和蝾螈之间不同再生结果的基础。基于机械的干预将“不完美”再生的蜥蜴尾巴转变为“完美”再生蝾螈尾巴的可行性。目标是：（1）操纵再生蝾螈尾巴中存在但蜥蜴尾巴中不存在的背腹信号。引入在蝾螈而非蜥蜴尾巴中发现的干细胞群；以及（3）确定和操纵蜥蜴尾巴中不存在的再生蝾螈尾巴中的增殖信号，提出了一种综合方法，结合转录组学、蜥蜴干细胞的 CRIPSR/Cas9 基因组编辑、分子和细胞分析、体内手术操作和细胞递送。我们相信，这种方法将产生第一个蜥蜴尾巴，其骨骼表现出表型再生蝾螈尾巴的图案和分割。对脊椎动物再生过程的机制理解，可能会改善非再生生物体（包括人类）的愈合能力，特别是与骨骼发育和修复相关的能力。