Regulation of adult stem cell homeostatic response to inflammatory injury

描述（由申请人提供）：环境因素如微生物群或感染触发免疫介导的组织损伤，导致遗传易感受试者的慢性粘膜疾病，如炎症性肠病（IBD）。干细胞疗法最近在IBD的个性化治疗中取得了许多成功的案例，但肠上皮干细胞（IESC）治疗仍处于早期阶段。JAK-STAT的激活分别促进成体肠干细胞的分裂和分化，从而推动肠上皮细胞（IEC）的更新。我们最近报道了在结肠炎小鼠模型中，STAT5信号传导可预防肠屏障功能障碍并促进粘膜愈合。此外，我们的初步数据表明，STAT5的缺失降低了干细胞标志物Lgr5、Ascl2和Olfm4的表达，并抑制了成人iesc衍生类器官中NOTCH的激活和细胞连接成熟。因此，我们假设STAT5信号通过调节干细胞基因信号来促进细胞间连接的形成，从而控制成体IESC的活性；STAT5信号的激活增强了IEC类器官植入对抗感染诱导的肠屏障功能障碍。我们将用以下两个目标来检验我们的假设。我们的目标1将确定STAT5信号在成人IESC分化中的作用。本研究将首先在小鼠中诱导删除IEC STAT5或过度激活IEC STAT5，以表征成年小鼠肠内IESC稳态、干细胞基因谱和Wnt/Notch信号。其次，利用人类多能干细胞衍生的肠道类器官，我们将通过基因操纵STAT5的表达来确定STAT5在IESC分化过程中调控Wnt/Notch信号的作用。我们的目标2将定义STAT5信号对IEC单分子膜分化相关发展的要求。首先，我们将使用STAT5缺陷和STAT5诱导的iesc衍生类器官来表征紧密连接的发育。其次，我们将培养这些小鼠类器官植入受体对照小鼠，以评估IESC的完整性和紧密连接的形成。总之，我们将确定上皮细胞STAT5通过与NOTCH信号相互作用来调节干细胞基因信号，促进细胞间连接的重组，从而愈合粘膜炎症。我们的研究将证明STAT5在通过干细胞基因标记调节成体干细胞稳态中的重要作用，并将探索一种新的工程化组织疗法，直接治愈粘膜炎症期间上皮屏障的破坏。我们建议将这一研究领域的范式从理解STAT5信号作为干细胞生物学的基本调节因子转向开发潜在的治疗工具。我们相信这种探索性的R21机制将允许一个由基础科学家和临床研究者组成的合作团队开始一个全新的项目，并探索一种新的潜在的治疗途径，以恢复粘膜炎症中的上皮屏障功能障碍。

DESCRIPTION (provided by applicant): Environmental factors such as microbiota or infection trigger immune-mediated tissue injury, which leads to chronic mucosal diseases in the genetically susceptible subjects, such as Inflammatory Bowel Diseases (IBD). Stem cell therapy has recently achieved many successful cases in the personalized treatment of IBD, but intestinal epithelial stem cell (IESC) treatment is still at an early stage. JAK-STAT activation wa suggested to promote adult intestinal stem cell division and differentiation, respectively, and thereby could drive the renewal of intestinal epithelial cells (IEC). We recently reported that STAT5 signaling prevents intestinal barrier dysfunction and promotes mucosal healing in colitic mouse models. Furthermore, our preliminary data indicated that deletion of STAT5 decreased the expression of stem cell markers Lgr5, Ascl2, and Olfm4, and inhibited NOTCH activation and cellular junction maturation in adult IESC-derived organoid. We therefore hypothesize that STAT5 signaling controls adult IESC activity via regulation of a stem cell gene signature to promote intercellular junction formation; activation of STAT5 signaling enhances IEC organoid engraftment against infection-induced intestinal barrier dysfunction. We will test our hypotheses with the following two Aims. Our Aim 1 will determine the role of STAT5 signaling for adult IESC differentiation. The studies in this Aim will, first, inducibly delete IEC STAT5 or hyperactivate IEC STAT5 in mice to characterize IESC homeostasis, stem cell gene profiles, and Wnt/Notch signaling in adult mouse intestines. Second, using human pluripotent stem cells-derived intestinal organoids, we will genetically manipulate STAT5 expression to define STAT5's role in the regulation of Wnt/Notch signaling during IESC differentiation. Our Aim 2 will define the requirement of STAT5 signaling for differentiation-associated development of IEC monolayers. First, we will characterize tight junction development using both STAT5 deficient and STAT5 inducible IESC-derived organoids. Second, we will culture these mouse organoids to implant the recipient control mice to assess IESC integrity and tight junction formation. Overall, we will determine that epithelial STAT5 regulates a stem cell gene signature via interplay with NOTCH signaling to promote intercellular junction reformation for healing mucosal inflammation. Our studies will demonstrate an essential role for STAT5 in the regulation of adult stem cell homeostasis via a stem cell gene signature, and will explore a novel engineered tissue therapy that directly heals the epithelial barrier disruption during mucosal inflammation. We propose a paradigm shift for this research field from understanding STAT5 signaling as an essential regulator of stem cell biology toward developing the potential therapeutic tool. We believe this exploratory R21 mechanism will permit a collaborative team of basic scientists and clinical investigators to start a brand-new project, and explore a novel potential therapeutic avenue for restoring epithelial barrier dysfunction in mucosal inflammation.