In vivo analysis of mechanotransduction

机械转导的体内分析 生物管中的细胞必须结合生化和机械信号才能扩张或 以协调一致的方式签约。对不断变化的国家做出不恰当的反应是基础 心脏病、高血压和哮喘等疾病。尽管来自生物物理学的见解 从工程底物的细胞生物学来看，许多重要的问题仍然存在 机械信息如何被细胞感知，转化为生化信号，以及 整合以产生协调的组织水平的反应。例如，多细胞是如何 收缩能力在空间和时间上受到调节吗？生化的诱导和繁殖是如何进行的 信号受机械信号控制吗？一个组织内不同类型的细胞如何协调 他们的行为？为了解决这些问题，我们开发了一种体内模型，线虫 受精囊，是线虫生殖系统中的一种管状组织，由24 通过环形瓣膜与子宫相连的平滑肌样细胞。主要优势 这一系统的特点是，当卵母细胞进入时，细胞自然伸展和收缩，并 服从定量实时成像和靶向基因操作，使观察成为可能 以及在完整组织的背景下操纵单个细胞。我们发现， 卵母细胞进入诱导钙离子脉冲横扫组织，最终形成协调的 将受精的胚胎推入子宫的收缩。钙离子释放与心肌细胞的收缩 受精囊和瓣膜是协调的，当受精囊袋收缩时， 瓣膜扩张以允许受精胚胎退出。保守的基因网络调节这些 过程，这表明我们的发现广泛适用于其他收缩系统。在这里，我们 提出了一种结合基因编码生物传感器、蛋白质组学、分子 遗传学和模型，以阐明协调钙信号转导的机制 对拉伸的反应。具体地说，我们将1)检验这一假设，即异三聚体G蛋白， GαS，通过蛋白激酶A信号调节精子膜收缩能力；2)通过 哪种拉伸触发钙释放和信号传播；以及3)决定瓣膜如何 收缩能力是自主调节的，也是通过与精囊袋的通讯调节的。 这项研究将在我们对基本原理的理解方面取得重大进展 细胞将机械信息转化为生化信号的机制，以及如何 这种信号被整合起来，以调节组织功能。

In vivo analysis of mechanotransduction Cells in biological tubes must integrate biochemical and mechanical cues in order to expand or contract in a coordinated manner. Inappropriate responses to changing states underlie conditions such as heart disease, hypertension and asthma. Despite insights from biophysics and from cell biology on engineered substrates, many important questions remain regarding how mechanical information is sensed by cells, translated into biochemical signals, and integrated to produce a coordinated tissue-level response. For example, how is multicellular contractility regulated in space and time? How are the induction and propagation of biochemical signals regulated by mechanical cues? How do different cell types within a tissue coordinate their actions? To address these questions, we have developed an in vivo model, the C. elegans spermatheca, which is a tubular tissue in the nematode reproductive system comprised of 24 smooth-muscle-like cells that connect to the uterus via a toroidal valve. The major advantages of this system are that the cells are naturally stretched and contract as oocytes enter, and are amenable to quantitative live imaging and targeted genetic manipulation, enabling observation and manipulation of individual cells in the context of an intact tissue. We have discovered that oocyte entry induces Ca2+ pulses that sweep across the tissue, culminating in a coordinated contraction that pushes the fertilized embryo into the uterus. Ca2+ release and contractility in the spermatheca and valve are coordinated such that while the spermathecal bag contracts, the valve dilates to allow exit of the fertilized embryo. Well-conserved gene networks regulate these processes, suggesting broad applicability of our findings to other contractile systems. Here, we propose a combination of 4D imaging of genetically-encoded biosensors, proteomics, molecular genetics, and modeling to elucidate the mechanisms which coordinate Ca2+ signaling in response to stretch. Specifically, we will 1) test the hypothesis that the heterotrimeric G protein, Gαs, signals through PKA to regulate spermathecal contractility; 2) model the mechanisms by which stretch triggers calcium release and signal propagation; and 3) determine how valve contractility is regulated, both autonomously and via communication from the spermathecal bag. This research will lead to important advances in our understanding of the fundamental mechanisms by which cells convert mechanical information into biochemical signals, and how this signaling is integrated to regulate tissue function.