Molecular and Cellular Mechanisms of Wound Repair and Morphogenesis

描述(申请人提供)：用于修复单细胞膜撕裂的伤口修复机制和用于恢复多细胞组织伤口上皮完整性的创伤修复机制在规模上有很大的不同，但两者都是生存的关键，并涉及一系列古老而高度保守的过程。因此，细胞和组织修复既具有基本的细胞生物学意义，又具有重要的临床意义。这项建议的总体目标是在整个生物体的活体背景下了解细胞和组织创伤修复的生物学基础。我们对肌动蛋白/微管细胞骨架的协调调节以及肌动蛋白成核因子在这些过程中的作用特别感兴趣。本研究建议研究果蝇伤口修复的机制，以利用其易于活体成像的能力和其卓越的遗传可控性，这在目前的伤口愈合模型中是不存在的。我们最近在果蝇合胞胚胎中开发了一种单细胞创伤修复模型，该模型与后期胚胎的多细胞组织创伤修复模型一起，可以很容易地比较候选创伤基因的野生型和突变型胚胎的修复，这使得在这些修复过程中筛选新的遗传角色成为可能。这项建议的具体目的是使用分子、遗传学和细胞生物学相结合的方法：1)研究肌动蛋白和微管细胞骨架在单细胞和多细胞组织创伤修复中的作用；2)表征Rho1 GTP酶作为两种创伤修复过程调节因子的功能；以及3)确定两种修复过程的组成部分/机制和调控途径。我们的长期目标是准确地了解调节这些不同规模的伤口修复过程的参与者和事件。与伤口修复相关的形态运动与正常的形态发生事件有许多相似之处。因此，我们在这里学习的特性将影响我们对构成正常形态发生基础的基本生物学事件和规则的理解。除了单纯的皮肤修复，我们的研究还将在许多疾病情况下具有基本的临床意义，并有望为组织修复疗法的进一步设计提供指导，以提高愈合速度和/或防止瘢痕形成，以及对组织重建至关重要的组织工程。 公共卫生相关性：生物体修复伤口的能力是一种基本的生存机制。人体容易受到多细胞组织(如皮肤)和单细胞(如肌肉细胞)的损伤，必须能够迅速修复这两种类型的损伤，以防止感染和恢复功能。拟议中的研究使用苍蝇胚胎作为模式生物，在其中定义伤口修复的准确细节，并将其与正常发育过程进行比较。我们的发现可以很容易地推断到脊椎动物模型，并将有助于设计新的伤口修复疗法，可能会加快愈合过程和/或防止过度疤痕。

DESCRIPTION (provided by applicant): The wound repair mechanisms used to mend a tear in the membrane of a single cell and those that restore epithelial integrity to multicellular tissue wounds operate on massively different scales, but both are critical for survival and involve a series of ancient and highly conserved processes. Cell and tissue repair is thus of both fundamental cell biology interest and significant clinical relevance. The general aim of this proposal is to understand the biological basis of both cell and tissue wound repair within the in vivo context of a whole organism. We are particularly interested in the coordinated regulation of the actin/microtubule cytoskeletons and in the role of actin nucleation factors in these processes. This study proposes to investigate the mechanisms of wound repair in Drosophila in order to utilize its amenability for live imaging in concert with its superb genetic tractability not available in current wound healing models. We have recently developed a single cell wound healing model in Drosophila syncytial embryos that along with the multicellular tissue wound healing model of later staged embryos allows easy comparison of repair in wildtype versus embryos mutant for candidate wound genes, and that makes it possible to screen for novel genetic players in these repair processes. The specific aims of this proposal are to use combined molecular, genetic and cell biological approaches to: 1) examine the roles of the actin and microtubule cytoskeletons in single cell and multicellular tissue wound repair; 2) characterize the functions of the Rho1 GTPase as a regulator of both wound repair processes; and 3) identify the components/machineries and regulatory pathways of both repair processes. Our long-term goal is to understand precisely the players and events that regulate these differently scaled wound repair processes. The morphological movements associated with wound repair share many similarities with normal morphogenetic events. Thus, the properties we learn here will impact our understanding of the basic biological events and regulations that underlie normal morphogenesis. Our studies will also be of fundamental clinical significance in many disease situations besides simply that of skin repair and is expected to provide insight that may guide further design of tissue repair therapies to enhance healing speed and/or prevent scarring, as well as for tissue engineering central to reconstructing tissues. PUBLIC HEALTH RELEVANCE: The capacity of an organism to repair a wound is a basic survival mechanism. The human body is subject to injuries to both multicellular tissues such as the skin, and to single cells such as muscle cells, and must be able to rapidly repair both types of damage to prevent infection and to restore function. The proposed studies use the fly embryo as a model organism in which to define the precise details of wound repair and compare that to normal developmental processes. Our findings can be easily extrapolated to vertebrate models, and will be useful in the design of new wound repair therapies that may speed the healing process and/or prevent excessive scarring.