A Comprehensive Endogenous Basement Membrane Toolkit to Elucidate how Basement Membranes Stretch on Mechanically Active Tissues and Decline during Aging

项目摘要 基底膜（BM）是细胞外基质蛋白质的薄的、致密的、超分子组装体， 并提供组织功能所必需的机械和信号支持。遗传和 BM组分的调节缺陷是许多疾病的基础，例如糖尿病、肾脏和心血管疾病。 疾病，并且衰老期间BM的增厚被认为是组织衰退的关键驱动因素。尽管批评 由于BM对人类健康的重要性，目前还没有允许全面的、真实的时间的动物模型 BM组件的可视化和实验操作，以研究BM调节的关键方面， 阻碍了治疗BM疾病的疗法的发展。本建议的总体目标是 在C中创建内源性荧光标记的BM组分的完整工具包。用这些 应变开发模型，以实验研究BM的两个重要方面：BM如何拉伸以支持 机械活性组织，以及BM如何在老化过程中积累胶原蛋白、胶原蛋白并导致组织衰退。 C.秀丽线虫具有编码大多数主要BM蛋白组分的单基因，光学透明，并且具有条件性生长。 敲低方法，这有助于对BM调节和功能的有力洞察。前期工作已 使用Cas9介导的同源重组将mNeonGreen（mNG）荧光团与57个 的98 BM相关基因，已被证实的蛋白质表达和活力。同源性，基因组 编辑位点和胚胎蛋白定位正在一个新创建的数据库中编目 （基底膜BASE）。初步研究还表明，在排卵期间，BM伸展近两倍- 倍，以支持受精囊组织，和BM的胶原蛋白和IV型胶原蛋白水平显着增加 （~ 5倍）在C. elegans老化为了完成一个BM的目标， 工具包和开发模型来研究BM拉伸和老化，将追求以下具体目标：（1） 用mNG完成所有BM组分的内源性标记， mScarlet-I和mEos 2（光电转换），（2）使用可视化BM工具包建立新的模型，揭示如何 BM拉伸以支持C期间的组织完整性。elegans排卵，（3）开创了第一个实验模型 研究衰老过程中BM胶原积累、BM增厚和组织衰退的机制。 这项研究将通过开发试剂，有力地促进我们对BM拉伸和老化的理解。 以及动态跟踪BM组件存在和级别、确定BM组件添加 通过光漂白后荧光恢复（FRAP）评估BM去除率，并通过 光转换初步研究已经揭示了一种独特的受精囊BM成分， 允许BM伸展，并且BM胶原蛋白是在老化期间增加的唯一核心BM组分。的 拟议的研究是重要的，因为创建的工具和方法将提供强大的新方法， 研究BM并建立新的模型，以阐明BM调节和功能障碍的关键方面。

PROJECT SUMMARY Basement membranes (BMs) are thin, dense, supramolecular assemblies of extracellular matrix proteins that surround animal tissues and provide mechanical and signaling support essential for tissue function. Genetic and regulatory defects in BM components underlie numerous diseases, such as diabetes, kidney, and cardiovascular disease, and thickening of BM during aging is thought to be a key driver of tissue decline. Despite the critical importance of BMs to human health, there are currently no animal models that allow comprehensive, real time visualization and experimental manipulation of BM components to study key aspects of BM regulation, which has hindered the development of therapies to treat BM disorders. The overall objective of this proposal is to create a complete toolkit of endogenously fluorescently tagged BM components in C. elegans and use these strains to develop models to experimentally examine two important aspects of BMs: How BMs stretch to support mechanically active tissues, and how BMs accumulate collagen, thicken, and cause tissue decline during aging. C. elegans has single genes encoding most major BM protein components, is optically clear, and has conditional knockdown approaches, which facilitates powerful insight into BM regulation and function. Preliminary work has used Cas9-mediated homologous recombination to insert the mNeonGreen (mNG) fluorophore in-frame with 57 of 98 BM-associated genes, which have been confirmed for protein expression and viability. Homology, genome editing sites, and embryonic protein localization are being cataloged on a newly created database (basementmembraneBASE). Pilot studies have also revealed that during ovulation the BM stretches nearly two- fold to support the spermathecal tissue, and that BMs thicken and type IV collagen levels increase dramatically (~five-fold) within BMs on multiple tissues during C. elegans aging. To complete the objective of finishing a BM toolkit and developing models to study BM stretching and aging, the following specific aims will be pursued: (1) finishing the endogenous tagging of all BM components with mNG and tagging core BM components with mScarlet-I and mEos2 (photoconversion), (2) to use the visual BM toolkit to establish a new model to reveal how BM stretches to support tissue integrity during C. elegans ovulation, and (3) pioneer the first experimental model to study mechanisms of BM collagen accumulation, BM thickening, and tissue decline during aging.The proposed study will powerfully advance our understanding of BM stretching and aging by developing reagents and methodologies to dynamically track BM component presence and levels, determine BM component addition rates through fluorescent recovery after photobleaching (FRAP), and to assess BM removal rates through photoconversion. Preliminary studies have already revealed a unique spermathecal BM composition that likely allows the BM to stretch, and that BM collagen is the only core BM component that increases during aging. The proposed research is significant, as the tools and methods created will provide powerful new approaches to study BMs and establish new models to elucidate key aspects of BM regulation and dysfunction.