Exploring Wnt-Fzd signaling specificities

项目概要/摘要： 细胞间的通讯是多细胞生命进化的核心：细胞发送特定的信号来指示 他们的邻居采取不同的命运自己。一类重要的发育信号是由 Wnt基因家族Wnt蛋白与卷曲蛋白家族的同源受体相互作用， 无数的发育过程，从建立组织内单个细胞的极性到指定 生物体的前后体轴。Wnt信号的失调可能会导致灾难性的 后果，包括胚胎死亡，出生缺陷和疾病。他们的多样而有力的活动 在发育和干细胞中，Wnt蛋白作为细胞和组织工程中的有效工具具有很大的前景。 我们研究的长期目标是更好地了解Wnt蛋白及其功能 下游信号事件影响细胞命运的决定，从而促进技术和治疗 专门针对Wnt信号传导。多年来，我们为促进 开发Wnt作为研究级试剂来操纵人类多能干细胞（hPS）， 产生具有潜在治疗价值的细胞群。然而，需要应对重大挑战。 在Wnt作为治疗剂的全部潜力可以实现之前解决。特别是，尽管它们具有强大的 尽管Wnt蛋白具有生物活性，但许多Wnt蛋白仍然难以以生物活性和稳定的形式分离。此外，委员会认为， 有19种Wnt和20多种Wnt受体（包括Fzd 1 -10、Lrp 5/6、Ror 1/2等）。编码在哺乳动物 基因组，目前还不清楚信号特异性是如何建立的。最后，目前许多针对Wnt的尝试 临床环境中的信号传导是高度非特异性的，并产生并发症和不良副作用。 未来五年的目标是利用我们实验室开发的创新技术， 工程化的Wnt激动剂，称为Wnt模拟物，其与 天然Wnt蛋白。这些Wnt模拟物将在几种环境中测试其效果，包括hPS细胞 自我更新和分化，类器官培养物和整个动物（小鼠）。此外，拟议的 研究将探索一种新的范式，用于研究Wnt信号特异性如何在体内建立，从而 使工具和方法的发展，精确定位个别Wnt信号通路。这些 实验将使我们能够验证我们的假设，即个体Wnt的选择性参与和激活 受体和受体复合物触发不同的信号输出和生物效应。 这项研究将大大推进干细胞研究和组织工程领域， 建立新的工具和方法来在体外和体内操纵Wnt信号传导。其丰富的作用， 更好地理解Wnt信号传导对于人类疾病的发展至关重要。 目前无法治愈的疾病的新疗法。

Project Summary/Abstract: Cell-cell communication lies at the heart of evolution of multi-cellular life: cells send specific signals to instruct their neighbors to adopt fates distinct of their own. An important class of developmental signals is encoded by the Wnt gene family. Wnt proteins interact with their cognate receptors of the Frizzled (Fzd) family to control countless developmental processes, from establishing the polarity of a single cell within a tissue to specifying the anterior-posterior body axis of an organism. Deregulation of Wnt signaling can have catastrophic consequences, including embryonic lethality, birth defects, and disease. With their diverse and potent activities in development and stem cells, Wnt proteins hold great promise as potent tools in cell and tissue engineering. The long-term objective of our research is to gain a better understanding of how Wnt proteins and their downstream signaling events influence cell fate decisions, and thereby advance technologies and treatments that specifically target Wnt signaling. Over the past years, we have made important contributions to the development of Wnts as research-grade reagents to manipulate human pluripotent stem (hPS) cells and generate cell populations with potential therapeutic value. However, significant challenges need to be addressed before the full potential of Wnts as therapeutics can be realized. In particular, despite their potent activities, many Wnt proteins remain difficult to isolate in a biologically active and stable form. Furthermore, with 19 Wnts and over 20 Wnt receptors (including Fzd1-10, Lrp5/6, Ror1/2, etc.) encoded in the mammalian genome, it is unclear how signaling specificity is established. Finally, many current attempts to target Wnt signaling in clinical settings are highly non-specific and produce complications and adverse side effects. The goal for the next five years is to leverage an innovative technology developed in our laboratory that utilizes engineered Wnt agonists, called Wnt mimetics, which exhibit superior biochemical properties compared to native Wnt proteins. These Wnt mimetics will be tested for their effects in several settings, including hPS cell self-renewal and differentiation, organoid cultures and in whole animals (mice). Furthermore, the proposed research will explore a new paradigm for how Wnt signaling specificity is established in vivo, and thereby enable the development of tools and approaches that pinpoint individual Wnt signaling pathways. These experiments will allow us to test our hypothesis that selective engagement and activation of individual Wnt receptors and receptor complexes trigger distinct signaling outputs and biological effects. The proposed research will significantly advance the field of stem cell research and tissue engineering by establishing new tools and methods to manipulate Wnt signaling in vitro and in vivo. With its abundant roles in human disorders and diseases, a better understanding of Wnt signaling is essential for the development of novel therapies for currently incurable diseases.