Mechanisms of Lens Morphogenesis and Regeneration

描述（由申请人提供）：为了在损伤后再生功能性组织或替换因病理性疾病后果而破坏的组织，干细胞或祖细胞的分化必须伴随着促进组织形态发生的有效策略。本研究旨在探讨细胞和组织形态发生的机制，最终目的是应用这些结果来指导组织修复和再生中正常发育过程的再现。这些研究的模型是胚胎晶状体，是研究形态发生的分子机制的理想模型，因为它的细胞结构决定了它的功能。晶状体的形态发生必须精确地进行，它的结构必须保持，以便它在视网膜上执行聚焦图像的功能。本研究旨在发现晶状体发育的两个主要形态发生事件的机制：1)建立高度细长的晶状体纤维细胞表型的延伸/收敛延伸机制；2)相邻晶状体纤维细胞被组织成精确六边形排列的细胞阵列的机制。这些研究主要集中在n -钙粘蛋白连接及其与不同细胞骨架元件的动态相互作用，作为细胞和组织形态发生的关键调节剂。在这些研究中，我们开发了一些重要的文化模型，包括：1)体外模拟白内障手术培养，可以检查晶状体上皮在其原生微环境中对临床相关损伤的反应及其再生晶状体样组织的能力；2)晶状体上皮细胞的原代培养，在培养中分化形成微型晶状体结构；3)上皮外植体，纤维细胞伸长并组织成高度有序的组织样结构；除了n -钙粘蛋白纤维细胞特异性敲除。这些模型提供了强大的工具，用于检查n -钙粘蛋白作为一个焦点，其中肌动蛋白微丝，微管和中间丝协调其功能以指导晶状体形态发生，并提出以下问题：驱动纤维细胞伸长的机制是什么？邻近的晶状体纤维细胞是如何相互作用形成功能结构的？是什么调节了纤维细胞的组织

DESCRIPTION (provided by applicant): In order to regenerate a functional tissue following an injury or to replace a tissue destroyed by the consequences of a pathological disease, the differentiation of stem or progenitor cells must be accompanied by effective strategies to promote tissue morphogenesis. This proposal investigates the mechanisms that guide cell and tissue morphogenesis with the ultimate goal of applying the results to instruct the recapitulation of normal developmental processes in tissue repair and regeneration. The model for these studies is the embryonic lens, ideal for investigating the molecular mechanisms of morphogenesis because its cytoarchitecture defines its function. Morphogenesis of the lens must be precisely executed and its structure maintained in order for it to perform its function of focusing images on the retina. This proposal aims to discover the mechanisms responsible for the two principal morphogenetic events of lens development: 1) the elongation/convergent extension mechanism that establishes the highly elongated lens fiber cell phenotype and 2) the mechanism by which neighboring lens fiber cells are organized into an exact hexagonally packed cellular array. The studies are focused on N-cadherin junctions and their dynamic interactions with different cytoskeletal elements as key modulators of cell and tissue morphogenesis during development. For these studies we developed a number of important culture models including: 1) ex vivo mock cataract surgery cultures where it is possible to examine the response of the lens epithelium to a clinically relevant wounding in its native microenvironment and its ability to regenerate lens-like tissue, 2) primary cultures of lens epithelial cells that differentiate in culture to form mini-lens structures, and 3) epithelial explnts where fiber cells both elongate and organize into a highly ordered tissue-like structure; in addition to N-cadherin fiber cell-specific knockouts. These models provide powerful tools with which to examine N-cadherin as a focal point where actin microfilaments, microtubules and intermediate filaments coordinate their function to direct lens morphogenesis with the following questions: What are the mechanisms that drive fiber cell elongation? How do neighboring lens fiber cells interact to form a functional structure? What regulates the organization of fiber cells into a hexagonal array? What stabilizes this unique cytoarchitecture of the lens? How do lens epithelial cells remodel their N-cadherin/cytoskeletal interactions for wound healing and tissue regeneration? The results of these proposed studies are expected to identify the underlying mechanisms responsible for establishing and maintaining cell and tissue cytoarchitecture, knowledge of which would provide substantive targets for guiding effective tissue regeneration in vivo. PUBLIC HEALTH RELEVANCE: The studies in this proposal examine the importance of dynamic interactions between N-cadherin junctions and the cytoskeleton in directing both cell and tissue morphogenesis, focusing on mechanisms that regulate the morphogenetic movement of cells in development and how these cells become arranged into highly ordered structures required for tissue function. This approach addresses one of the greatest challenges in Regenerative Medicine, how following an injury or in response to tissue damage resulting from a pathological disease, reparative cells can be induced to undergo morphogenetic differentiation and interact with their near neighbors to form a new tissue. Our studies are expected to provide functional targets for promoting tissue regeneration.