Extracellular Matrix Modulation of Cell Phenotype

描述(由申请人提供)：细胞外基质(ECM)通过其在组织结构中的作用以及对细胞生长、迁移和分化的刺激作用，对细胞决策至关重要。细胞外基质信号的传递是通过整合素受体实现的，整合素受体将细胞外基质与肌动蛋白细胞骨架连接起来，并激活各种信号通路。要了解细胞如何协调细胞外信号和细胞内过程，需要对细胞外基质的组成和组织以及对细胞-细胞外基质相互作用做出反应的细胞内分子的信息有深入的了解。我们正在通过分析线虫的性腺发生来解决这些问题。线虫两性性腺的形成在孵化后发生，依赖于两个末端细胞(DTC)沿体壁基底膜基质的迁移。在全基因组筛选中，我们确定了这一过程所需的99个基因。在这里，我们将集中讨论其中的几个基因，它们在DTC迁移的启动和DTC转向形成U型性腺臂的过程中发挥关键作用。保守的基底膜蛋白PPN-1的缺失会完全阻断DTC的迁移。组织分布、表达的时机和调节、突变体的挽救和蛋白结构域的表达将被用来确定乳头素在性腺形成中的作用。另外，还将利用也表达该基因的人乳腺上皮细胞，对该基因的定位和功能进行体外补充研究。为了确定DTCs如何与基底膜相互作用，我们将确定介导迁移的线虫整合素受体的ECM配体。ECM指导细胞转向和伴随的细胞极性的变化，这一过程依赖于两个新基因和性腺发生过程中PAT-2整合素的表达。对这些基因的功能分析和迁徙中的DTC的延时视频显微镜将确定旋转的分子要求。这些目标的结果将提供关于细胞-ECM相互作用在组织形态发生过程中细胞重排和迁移的调节作用的新信息。 与公共卫生相关：大多数(如果不是全部)人类疾病的进展是由细胞外基质的扰动促进的，细胞外基质是围绕细胞的蛋白质和碳水化合物网络。细胞外基质在将细胞组织成组织和控制器官功能方面起着至关重要的作用。拟议的研究将提供关于细胞与细胞外基质连接的变化如何影响器官发育的新信息，并将提供关于细胞外基质变化如何导致人类疾病的新想法。

DESCRIPTION (provided by applicant): The extracellular matrix (ECM) is critical for cellular decision-making through its role in tissue architecture and its stimulatory effects on cell growth, migration, and differentiation. Transmission of ECM signals is carried out by integrin receptors that link the ECM to the actin cytoskeleton and activate various signaling pathways. To understand how cells coordinate extracellular signals with intracellular processes requires insights into the composition and organization of the ECM as well as information about the intracellular molecules that respond to cell-ECM interactions. We are approaching these questions by analyzing gonadogenesis in the nematode Caenorhabditis elegans. Formation of the C. elegans hermaphrodite gonad occurs after hatching and depends on migration of two distal tip cells (DTCs) along the body wall basement membrane matrix. In a genome-wide screen, we identified 99 genes that are required for this process. Here we will focus on several of those genes that play critical roles in initiation of DTC migration and in DTC turning to form the U- shaped gonad arms. Loss of the conserved basement membrane protein papilin (ppn-1) causes a complete blockade of DTC migration. Tissue distribution, timing and regulation of expression, rescue of mutants, and expression of protein domains will be used to define papilin's role in gonad formation. Complementary in vitro studies of papilin localization and function will be performed using human mammary epithelial cells which also express this gene. To determine how DTCs interact with basement membranes, we will identify the ECM ligands for the C. elegans integrin receptors that mediate migration. The ECM directs cell turning and accompanying changes in cell polarity, processes that are dependent on two novel genes and on expression of the pat-2 integrin during gonadogenesis. Functional analyses of these genes and time-lapse video microscopy of migrating DTCs will define molecular requirements for turning. Results from these aims will provide novel information about the regulatory role of cell-ECM interactions in cell rearrangements and migration during tissue morphogenesis. Public Health Relevance: Progression of most, if not all, human diseases is facilitated by perturbations in the extracellular matrix, the network of proteins and carbohydrates that surrounds cells. The extracellular matrix plays essential roles in organizing cells into tissues and controlling organ function. The proposed studies will provide novel information about how changes in cell connections to the extracellular matrix affect organ development and will provide new ideas about how alterations in extracellular matrix contribute to human disease.