The impact of the physical microenvironment on trophoblast function

胎盘是怀孕期间发育的一个关键器官，让胎儿获得营养并清除排泄物。胎盘既是守门人，又是内分泌器官，这两个功能对健康的怀孕至关重要。然而，胎盘在系统受到干扰后的作用还不是很清楚，因为在怀孕的所有阶段都需要获得组织的伦理问题，以及缺乏所需的控制水平和生理相关性的糟糕的体外或体外系统。在初步研究中，我们成功地制作了一个体外微流控胎盘模型，允许在天然蛋白质凝胶中培养三种不同类型的细胞(滋养层细胞、成纤维细胞和内皮细胞)。微流控通道将切应力引入到模型中，三细胞培养允许细胞间的交流，这两者都被证明对生理上相关的滋养层细胞表型至关重要。细胞可以(1)轻松、(2)平行、(3)严格控制、(4)不需要微流体技术专业知识，在来自人类胎盘的天然基质上培养。该模型可以很容易地更新，以研究健康或调节失调的胎盘的许多机械和基本性质。妊娠期可能导致并发症的一种疾病，先兆子痫(PE)，与子宫壁有限重塑造成的胎盘破坏有关；这一过程对于确保健康的胎盘组织、适当的氧气浓度和适当的胎盘内切应力至关重要。由于缺乏子宫重塑，胎盘细胞外基质(ECM)通过纤维化而硬化，氧分压降低，切应力增加。我们假设胎盘内的这些物理微环境线索导致滋养细胞功能紊乱，这可以在我们新的微流体胎盘模型中进行机械检查。在目标1中，我们将改变我们的微流控装置，以测试ECM失调是如何改变滋养层功能的。我们将从I型胶原和人胎盘来源的细胞外基质中制造出健康或致病的硬化层。胎盘来源的ECM将使我们能够测试胎盘ECM的完整环境如何影响滋养层功能，而I型胶原ECM将允许更严格地控制环境。在目标2中，我们将测试氧张力和切应力对滋养层功能的密切关系。设备将在健康或致病的氧张力和剪切力下培养，以阐明它们的刺激是否具有协同作用。这些研究将证明我们的系统在能够控制系统的微物理特性以阐明胎盘多细胞模型的机械特性方面是容易的。

The placenta is a critical organ that develops during pregnancy to allow the fetus to obtain nutrients and remove waste. The placenta acts as both a gatekeeper and an endocrine organ; two functions which are vital for a healthy pregnancy. However, how the placenta acts after perturbations of the system is not well known due to ethical concerns regarding obtaining tissue throughout all stages of pregnancy and poor in vitro or ex vivo systems that lack the level of control and physiological relevance needed. In preliminary studies, we have successfully made an in vitro microfluidic placenta model that allows for culture of three different cell types (trophoblast, fibroblasts, and endothelial cells) within natural protein gels. Microfluidic channels incorporate shear stress into the model and the tri-cell culture allows for cell-cell communication which have both been shown to be vital for physiologically relevant trophoblast phenotype. Cells can be cultured on natural substrates derived from human placenta with (1) ease, (2) in parallel, (3) with tight control, and (4) without the need for technical expertise in microfluidics. The model can easily be updated to study many mechanistic and fundamental properties of the healthy or dysregulated placenta. One disease that can cause complications during pregnancy, preeclampsia (PE), is associated with disrupted placentation from limited remodeling of the uterine wall; a process vital to ensure healthy placental tissue, proper oxygen concentration, and appropriate amount of shear stress within the placenta. Due to the lack of uterine remodeling, placental extracellular matrix (ECM) is stiffened via fibrosis, oxygen tension is lowered, and shear stress is increased. We hypothesize that these physical microenvironmental cues within the placenta cause disrupted trophoblast function that can be mechanistically examined in our novel microfluidic placenta model. In Aim 1 we will alter our microfluidic device in order to test how ECM dysregulation alters trophoblast function. We will make stromal layers of healthy or pathogenic stiffnesses from both collagen-I and human placenta derived ECM. Placental derived ECM will enable us to test how the full milieu of the placenta ECM impacts trophoblast function, while the collagen-I ECM will allow for tighter control of the environment. In Aim 2 we will test the closely tied relationship between oxygen tension and shear stress on trophoblast function. Devices will be cultured at healthy or pathogenic oxygen tension and shear stress to elucidate if their stimuli are synergistic. These studies will demonstrate the ease of our system in being able to control the microphysical properties of the system for elucidation of mechanistic properties of multi-cell models of the placenta.