Intercellular interactions define cell migrations and transitions that maintain fetal membrane homeostasis

胎膜(羊膜)在怀孕期间保护胎儿。在足月，衰老(衰老)和炎症导致膜细胞功能和机械不稳定，导致分娩。早产(PTB)和胎膜早破(PPROM)与早衰和膜功能障碍有关。然而，细胞水平的变化有助于妊娠期间膜的稳定性及其导致分娩和分娩的功能障碍仍不清楚。最近对衰老的足月膜和早产膜的研究发现了“微骨折”(MFS)，即细胞重塑的部位。MFS在妊娠期间被重新密封，以保持膜的完整性。与各自的对照相比，足月分娩、pPROM和PTB膜中更多的MFS及其形态计量(深度和宽度)的增加表明MFS的再密封受到了损害。MFS中的羊膜上皮细胞经历了上皮间充质转化(EMT)。此外，这些细胞表现出增殖和再封闭的深度(裸体/无细胞)区域，以稳定膜。在MFS的愈合边缘，羊膜间充质细胞表现出一种相反的现象，即间充质-上皮转化(MET)。根据这些发现，我们推测细胞过渡对于维持胎膜的完整性是必不可少的。我们 假设MF是膜重塑的区域，其数量和形态计量的增加与膜重塑失败和功能障碍有关。了解细胞间和细胞基质 导致MFS发展和重新密封的相互作用将有助于我们确定氧化应激(OS)是如何 炎症可导致PTB和pPROM中MFS的持续存在和膜功能障碍。两个特定的测试目标是特定的目标1：在无细胞(裸)膜的体外模型中研究OS和感染/炎症与正常条件下的动态重构；特定的目标2：使用胎膜上的器官芯片方法来确定与MFS的形成相关的细胞迁移、基质降解和细胞转变。这一多学科的建议结合了细胞和分子生物学和生物工程方法，旨在通过使用芯片上器官技术开发胎儿芯片上膜来克服经典2D细胞培养的局限性。这个模型系统将保持多种细胞类型的紧密接近，并保持持续的动态相互作用，类似于子宫内的条件。我们将阐明(正常和异常)生物MFS形成的分子机制，以及它们在PTB和pPROM中的作用。了解细胞水平的机制将使我们能够设计策略，最大限度地减少MFS的发展，以加强宫内空洞，并降低PTB和pPROM的风险。

Fetal membranes (amniochorion) protect the fetus during pregnancy. At term, senescence (aging) and inflammation cause functional and mechanical instability to membrane cells, contributing to parturition. Premature senescence and membrane dysfunctions are associated with preterm birth (PTB) and preterm premature rupture of the membranes (pPROM). However, cellular-level changes contributing to membrane stability during gestation and its dysfunction leading to labor and delivery are still unclear. Recent studies of senescent term and preterm membranes revealed “microfractures” (MFs), sites of cellular remodeling. MFs are resealed during gestation to maintain membrane integrity. Higher numbers of MFs and their increased morphometry (depth and width) in term labor, pPROM, and PTB membranes compared to respective controls suggest MFs' resealing is compromised. Amnion epithelial cells in MFs have been observed undergoing epithelial mesenchymal transition (EMT). Further, these cells showed proliferative and resealing properties of deepithelialized (nude/cell free) areas to stabilize membranes. At the healing edge of MFs, amnion mesenchymal cells exhibited a reverse phenomenon, mesenchymal-epithelial transition (MET). From these findings, we postulate that cellular transitions are essential for maintaining fetal membrane integrity. We hypothesize that MFs are areas of membrane remodeling and their increased number and morphometry are associated with failure to remodel and dysfunctional membranes. Understanding intercellular and cell-matrix interactions causing MFs' development and their resealing will help us to determine how oxidative stress (OS) and inflammation can contribute to the persistence of MFs and dysfunctional membrane status in PTB and pPROM. Two specific aims to be tested are Specific Aim 1: To investigate the dynamic remodeling of the fetal membrane epithelium in an in vitro model of cell-free (nude) membranes during OS and infection / inflammation compared to normal conditions; Specific Aim 2: To determine cell migration, matrix degradation, and cellular transition associated with MFs' formation using a fetal membrane organ-on-a-chip approach. This multidisciplinary proposal combines cell and molecular biological and bioengineering approaches designed to overcome the limitations of classic 2D cell cultures by developing a fetal membrane-on-a-chip using organ-on-chip technologies. This model system will maintain multiple cell types in close proximity with constant dynamic interactions, similar to the conditions in utero. We will elucidate causative molecular mechanisms of (normal and abnormal) biologic MFs' formation and how they contribute to PTB and pPROM. Understanding cellular-level mechanisms will allow us to design strategies to minimize MFs' development to strengthen intrauterine cavities and reduce the risk of PTB and pPROM.