Basement membrane repair dynamics in the Drosophila midgut

基底膜是最古老、最保守的细胞外基质形式，用于分离组织 层，将信号引导到邻近细胞，将组织与信号隔离，并提供机械支持。此外，本发明还 基底膜易受机械损伤并需要修复。基底膜修复 可以帮助疾病的发展，如哮喘和糖尿病，以及基底膜疾病 包括Alport综合征和Goodpasture综合征。因此，了解地下室 膜修复对于治疗这些病症至关重要。我的工作利用果蝇中肠的地下室 膜探测修复动力学。在果蝇中，所有主要的基底膜成分都被 保守但比哺乳动物冗余少。我们的实验室已经开发出一种检测方法 基底膜损伤，研究修复过程。在损伤之后，基底膜变得 分别通过机械应力/应变测定和电子显微镜检查表明，刚性较低和密度较低。 此前有报道称，基底膜修复所需的过程也需要维持 基底膜没有被破坏;这些过程包括连续的基质合成， 调节酶（基质金属蛋白酶和过氧化物酶）。因此，不清楚地下室是否 主动检测膜损伤，或者相反，通过稳态机制被动修复膜损伤。我 初步数据表明基底膜损伤被主动检测到。损伤后， 基质成分在我们称之为基质制造者的肠道上皮细胞的特定亚群中上调， 可能是表达机械感觉拉伸激活离子通道Piezo的相同细胞。这就提出了一个 受损基底膜硬度的变化可能是修复开始的信号。压电 敲除果蝇能够在成年果蝇中组装和维持基底膜，但是，令人兴奋的是， 敲除不能修复受损后的基底膜。这是一种独特机制的证据， 检测基底膜损伤并启动修复。我假设基质硬度的降低 基底膜修复机制在目标1中，我提出了一个短暂的细胞群体的特点， 负责在基底膜损伤后合成新的基质成分。在目标2中，我 建议确定压电的作用及其对基底膜损伤的反应。我希望能找出 第一种检测和修复基底膜的机制。了解这一机制将 提供上皮生物学的基本见解，并将是至关重要的治疗和理解疾病的 基底膜。

Basement membranes are the oldest, most conserved forms of extracellular matrix and serve to separate tissue layers, direct signals to neighboring cells, insulate tissues from signals, and provide mechanical support. Further, basement membranes are subject to mechanical damage and require repair. Faulty basement membrane repair can aid in the progression of diseases such as asthma and diabetes, and diseases of the basement membrane itself, including Alport syndrome and Goodpasture syndrome. Therefore, understanding how basement membranes repair will be vital to treating these conditions. My work utilizes the Drosophila midgut basement membrane to probe repair dynamics. In Drosophila, all major basement membrane components have been conserved but with less redundancy than mammals. Our lab has developed an assay to reproducibly damage the basement membrane and study the repair process. Following damage, the basement membrane becomes less stiff and less dense, indicated by a mechanical stress/strain assay and electron microscopy, respectively. Previously it was reported that processes required for basement membrane repair are also required to maintain basement membranes that have not been damaged; these processes include continuous matrix synthesis and regulation of enzymes (matrix metalloproteinases and peroxidasin). Thus, it is unclear whether basement membrane damage is actively detected, or instead, passively repaired by homeostatic mechanisms. My preliminary data suggest basement membrane damage is actively detected. Following damage, the synthesis of matrix components is upregulated in a specific subset of gut epithelial cells we call matrix-makers, and these may be the same cells that express a mechanosensory stretch-activated ion channel, Piezo. This raises the possibility that a change in stiffness of damaged basement membranes signals the initiation of repair. Piezo knockout flies are able to assemble and maintain basement membranes in the adult fly, but, excitingly, Piezo knockouts cannot repair basement membranes after damage. This is evidence of a unique mechanism that detects basement membrane damage and initiates repair. I hypothesize that a loss in matrix stiffness triggers basement membrane repair mechanisms. In Aim 1, I propose to characterize a transient cell population responsible for synthesizing new matrix components following basement membrane damage. In Aim 2, I propose to identify the role of Piezo and its response following basement membrane damage. I expect to identify the first mechanism for detecting and repairing basement membranes. Understanding this mechanism will provide fundamental insights into epithelial biology and will be critical to treating and understanding diseases of the basement membrane.