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，用于分隔组织 层，将信号引导到邻近的细胞，将组织与信号隔绝，并提供机械支持。此外， 基底膜容易受到机械损伤，需要修复。故障基底膜修复 有助于哮喘和糖尿病等疾病以及基底膜疾病的进展 本身，包括阿尔波特综合征和古德帕斯图尔综合征。因此，理解地下室是如何 膜修复将是治疗这些疾病的关键。我的工作是利用果蝇的中肠地下室 膜以探查修复动力学。在果蝇中，所有主要的基底膜成分都是 与哺乳动物相比保守但冗余度较低。我们的实验室已经研制出一种可复制损伤的方法。 并研究基底膜的修复过程。损伤后，基底膜就会变成 机械应力/应变分析和电子显微镜分别表明材料不那么僵硬和致密。 此前有报道称，基底膜修复所需的过程也需要维持 基底膜没有受损；这些过程包括连续的基质合成和 酶(基质金属蛋白酶和过氧化物酶)的调节。因此，还不清楚地下室是否 膜损伤是主动检测的，或者是被动地通过内环境平衡机制修复的。我的 初步数据显示，基底膜损伤被积极检测到。在损伤之后，合成的 基质成分在特定的肠道上皮细胞亚群中上调，我们称之为基质制造细胞，这些 可能与表达机械感觉拉伸激活离子通道Piezo的细胞相同。这引发了 受损的基底膜硬度的变化可能预示着修复的开始。压电体 基因敲除的果蝇能够组装和维持成虫的基底膜，但令人兴奋的是，Piezo 基因敲除者在受损后无法修复基底膜。这是一种独特的机制的证据， 检测基底膜损伤并启动修复。我假设矩阵僵硬的损失会触发 基底膜修复机制。在目标1中，我建议描述瞬时细胞群体的特征 负责基底膜损伤后新基质成分的合成。在目标2中，我 建议确定Piezo的作用及其在基底膜损伤后的反应。我希望能确定 检测和修复基底膜的第一个机制。了解这一机制将 提供对上皮生物学的基本见解，并将对治疗和了解 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.