Systems-level role of GSK3 in colonic epithelium homeostasis and drug resistance

描述（由申请人提供）：自我更新的肠上皮细胞需要精确控制层来保持体内平衡。令人惊讶的是，肠上皮细胞每五天完全更新一次，在个体的整个生命中，多种细胞类型保持在正确的比例。然而，我们对上皮细胞如何保持如此强大的组织的理解还远未完成。缺乏这种精确的自我平衡控制是各种疾病的基础，包括克罗恩病，肠易激综合征，溃疡性结肠炎和胃肠道癌症。GSK-3是肠组织稳态中典型的信号中枢：它接收和破译多个上游微环境信号，选择性地影响多个下游细胞过程，并改变细胞对药物的反应。尽管GSK-3存在于许多细胞过程中，但其功能仍不清楚且研究不足。我们缺乏一个系统的了解GSK-3何时何地影响级联信号从微环境通过分子网络的背景下，复杂的上皮组织的细胞决策。在这里，我们建议研究GSK-3作为信号转导和维持组织稳态的枢纽的作用，以及确定药物类别，其作用取决于GSK-3在生理相关条件下的活动。为了实现这一目标，我们开发了：创新的肠上皮细胞器官型模型，非常适合基于图像的扰动分析; GSK-3活性的活细胞报告基因;以及定量， 单细胞方法用于破译GSK-3在将微环境信号转化为稳态决定中的作用。我们共同提议：（目的1）确定GSK-3相互作用网络，调节肠道稳态;（目的2）了解GSK-3的信号隔离和串扰的作用;（目的3）阐明GSK-3活性如何影响药物反应。

DESCRIPTION (provided by applicant): Self-renewing intestinal epithelium requires layers of precise control for homeostasis. Amazingly, intestinal epithelium completely renews itself every five days, with multiple cell types maintained at just the right ratios throughout an individual's entire life. However, our understanding of how epithelium maintains such robust organization is far from complete. Lack of this exquisite homeostatic control is the basis for a variety of diseases, including Crohn's disease, irritable bowel syndrome, ulcerative colitis, and gastrointestinal cancers. GSK-3 is a quintessential signaling hub in intestinal tissue homeostasis: it receives and deciphers multiple upstream microenvironmental signals, selectively affects multiple downstream cellular processes, and alters cellular response to drugs. Despite GSK-3's presence in many cellular processes, its function remains unclear and understudied. We lack a systematic understanding of when and where GSK-3 affects the cascade of signals from the microenvironment through molecular networks to cellular decisions in the context of complex epithelial tissues. Here, we propose to study the role of GSK-3 as a hub for signal transduction and maintenance of tissue homeostasis as well as identify drug classes whose effects depend on GSK-3 activities in physiologically relevant conditions. To accomplish this, we have developed: innovative organotypic models of gut epithelium that are ideal for image-based perturbation assays; live-cell reporters of GSK-3 activity; and quantitative, single-cell approaches for deciphering GSK-3's role in transforming microenvironmental signals to homeostatic decisions. Together, we propose to: (Aim 1) identify GSK-3 interaction networks that regulate gut homeostasis; (Aim 2) understand GSK-3's role in signal insulation and crosstalk; and (Aim 3) elucidate how GSK-3 activity affects drug response.