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

描述（由申请人提供）：自我更新的肠上皮需要层精确控制稳态。令人惊讶的是，肠上皮每五天就会完全自我更新一次，在个体的整个生命中，多种细胞类型保持着恰到好处的比例。然而，我们对上皮如何维持如此强健的组织的理解还远未完成。缺乏这种精细的体内平衡控制是多种疾病的基础，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是肠道组织稳态中一个典型的信号中枢：它接收和解读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，但其功能尚不清楚且研究不足。在复杂上皮组织中，GSK-3在何时何地通过分子网络影响微环境信号级联到细胞决策，我们缺乏系统的理解。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，并确定在生理相关条件下依赖GSK-3活性的药物类别。为了实现这一目标，我们开发了：创新的肠道上皮器官型模型，非常适合基于图像的扰动分析；GSK-3活性活细胞报告者；和定量,

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.