Alloreactive and autoreactive immune-mediated mechanisms of impaired epithelial regeneration in the GI tract

肠干细胞（ISCs）在免疫介导的胃肠道疾病中被靶向和耗尽的程度。 肠（GI）损伤和免疫系统在调节ISC介导的再生中的作用很差 明白同样，虽然已知T细胞迁移到肠道，但它们在肠道内的特定定位是不确定的。 当介导疾病时，组织和与ISC隔室的接近程度在很大程度上是未知的。合作 与NIDDK赞助的肠道干细胞联盟一起，该提案组建了一个多学科团队 阐明免疫系统如何在肠损伤期间影响ISC区室， 再生，以及评估克服这种损害和促进受伤者恢复的方法。 上皮我们的初步研究结果表明，ISCs和它们介导再生的能力在再生过程中丢失。 移植物抗宿主病（GVHD）引起的同种异体反应性损伤和调节性T细胞引起的自身反应性损伤 消耗，并且免疫细胞和肠道类器官的共培养物可用于建模和机械地 剖析这些过程。我们还发现，白细胞介素-22（IL-22）是一种重要的免疫信号， 系统增强ISC介导的损伤后再生。为应对以下问题而编制的新的初步数据： 评论者的评论指出，我们的自身免疫模型反映了效应T细胞急性活化的GVHD 和胃肠道归巢分子的上调，活化T细胞浸润胃肠道， IL-22治疗后的上皮损伤。F-652是Generon公司开发的新型rhIL-22二聚体，具有 翻译潜力，以促进ISC恢复和上皮再生体内。其他新数据 证明我们的三维成像方法可以量化ISC的丢失，ISC的特异性侵袭， 区室和血管整合素配体在GVHD中的定位。新的力学数据表明， MAdCAM-1阻断剂特异性抑制T细胞隐窝侵袭并保护ISC，表明该途径是一种免疫抑制剂。 是ISC损伤的重要调节因子，而不仅仅是整体肠道迁移。 我们将检验以下假设：1）T细胞募集到ISC区室，ISC的消耗，以及T细胞的丧失。 它们的再生能力是胃肠道中免疫介导的上皮损伤的共同特征，以及2）IL- 22施用可以保护ISCs并促进损伤后的再生。ISC功能和消耗将 用自身反应性和同种异体反应性实验方法评价，利用体内小鼠模型， 系统性自身免疫和GVHD以及小鼠和人肠类器官的离体培养物， 与UMC Utrecht合作，他们的类器官生物库和他们先进的ISC专业知识。IL-22治疗将 作为促进ISC功能的上皮靶向再生免疫疗法进行评估。不存在治疗 目前用于加速胃肠道从免疫病理学中恢复。这个项目将导致一个机械的 了解ISC区室和免疫系统之间的基本相互作用， 通过保护ISCs和增强再生治疗炎症性GI疾病的新方向。

The extent to which intestinal stem cells (ISCs) are targeted and depleted during immune-mediated gastro- intestinal (Gl) damage and the role of the immune system in regulating ISC-mediated regeneration are poorly understood. Likewise, while T cells are known to migrate to the intestines, their specific localization within the tissue and proximity to the ISC compartment when mediating disease are largely unknown. In collaboration with the NIDDK-sponsored Intestinal Stem Cell Consortium, this proposal assembles a multi-disciplinary team to elucidate how the immune system can influence the ISC compartment during intestinal damage and regeneration, as well as to evaluate approaches to overcome such damage and promote recovery of injured epithelium. Our preliminary findings indicate that ISCs and their ability to mediate regeneration are lost during both alloreactive injury from graft vs. host disease (GVHD) and autoreactive injury from regulatory T cell depletion, and that co-cultures of immune cells and gut organoids can be used to model and mechanistically dissect these processes. We have also found that Interleukin-22 (IL-22) is an important signal from the immune system augmenting ISC-mediated regeneration after injury. New preliminary data developed in response to reviewer comments indicate that our autoimmunity model mirrors GVHD with acute activation of effector T cells and upregulation of GI homing molecules, infiltration of the GI tract with activated T cells, and reduced epithelial damage after IL-22 treatment. F-652, a novel rhIL-22 dimer developed by Generon Corp., has translational potential to promote ISC recovery and epithelial regeneration in vivo. Additional new data demonstrate that our 3-D imaging approach can quantify loss of ISCs, specific invasion of the ISC compartment, and localization of vascular integrin ligands in GVHD. New mechanistic data indicate that MAdCAM-1 blockade specifically inhibits T cell crypt invasion and protects ISCs, indicating this pathway to be an important regulator of ISC injury, and not just overall gut migration. We will test the hypotheses that 1) T cell recruitment to the ISC compartment, depletion of ISCs, and loss of their regenerative capacity are common features of immune-mediated epithelial injury in the GI tract and 2) IL- 22 administration can protect ISCs and promote regeneration after damage. ISC function and depletion will be evaluated with autoreactive and alloreactive experimental approaches, utilizing in vivo mouse models of systemic autoimmunity and GVHD as well as ex vivo cultures of mouse and human intestinal organoids in collaboration with UMC Utrecht, their organoid biobank, and their advanced ISC expertise. IL-22 treatment will be evaluated as an epithelial-targeted regenerative immunotherapy promoting ISC function. No therapy exists currently to accelerate GI recovery from immunopathology. This project will lead to a mechanistic understanding of fundamental interactions between the ISC compartment and the immune system, opening a new direction for treatment of inflammatory GI diseases by protecting ISCs and augmenting regeneration.