Cell Lineage Analysis in Vertebrate Limb Regeneration

描述(申请人提供)：人们对再生过程知之甚少。这项提议旨在扩大对脊椎动物肢体再生过程的科学理解。在尾龙类两栖动物中，失去的肢体的再生被认为是通过剩余组织的去分化来产生胚芽，随后是细胞增殖和图案化事件，这些事件指导细胞的再分化来创造新肢体的组成部分。在这项建议的目标1中，将追踪再生的Axolotl肢体中的单个细胞谱系，以确定用于去分化的细胞的来源以及这些细胞在新肢体中的命运。干细胞对哺乳动物肢体再生的潜在贡献将在目标2中进行探索。在哺乳动物中，肢体再生仅限于指尖，随着年龄的增长，肢体再生越来越受到限制。目标2将检验这样一种假设，即在指尖发现的一组特定的干细胞，即表达msxl的细胞，赋予再生能力。为了验证这一假设，需要将msxl细胞移植到更近端的位置，并确定它们是否可以在那里诱导再生。如果是这样的话，这些细胞是否可以被操纵以允许近端元件的再生？

DESCRIPTION (provided by applicant): Regenerative processes are poorly understood. This proposal aims to expand scientific understanding of how regeneration occurs in vertebrate limbs. In urodele amphibians, regeneration of a lost limb is thought to occur by dedifferentiation of remaining tissues to create a blastema, followed by cell proliferation and patterning events that direct the redifferentiation of cells to create components of the new limb. In Aim 1 of this proposal, individual cell lineages within a regenerating axolotl limb will be traced to determine the source of cells used for dedifferentiation and the fate of these cells within the new limb. The potential contribution of stem cells to limb regeneration in mammals will be explored in Aim 2. In mammals, limb regeneration is restricted to digit tips and becomes increasingly restricted distally with age. Aim 2 will test the hypothesis that a specific set of stem cells, msxl-expressing cells, found at the digit tips confers regenerative ability. Testing this hypothesis will involve transplanting msxl cells to more proximal locations and determining if they can induce regeneration there. If so, can the cells be manipulated to allow regeneration of proximal elements?