Mechanisms of TL1A-driven Paneth Cell dysfunction in IBD

项目总结摘要 炎症性肠病(IBD)是一种慢性复发性胃肠道疾病，据信是 遗传易感性和严重程度基因、微生物环境、 以及针对共生微生物的失调的先天和适应性免疫反应。潘氏细胞 (PC)是一种特殊的小肠(SB)上皮细胞，它结构性地产生抗微生物蛋白，并 对肠道内环境的稳定很重要。克罗恩病患者的PC形态异常 (CD)和自噬和未折叠蛋白反应(UPR)途径中基因缺失的小鼠。小鼠带有 UPR和自噬途径中的PC特异性缺失会发展成早期和严重的SB炎症。个人电脑 回肠炎发病前的形态异常，暗示PC生物学改变是回肠炎的中心 SB CD的发病机制和严重程度；然而，驱动这些异常的细胞外部信号尚不清楚。 TNFSF15/(TL1A)是IBD的易感基因和严重程度基因，我们以前已经报道过这种关系 外周血单核细胞和非霍奇金淋巴瘤患者外周血单核细胞中TNFSF15危险基因和TL1A的表达增加 使某人CD发炎。在翻译研究中，我们也报道了这种危险基因与 严重形式的SB CD，包括纤维狭窄，在过度表达TL1A的小鼠中表现出来。我们有 发现TL1a与PC形态异常显著相关。共生微生物区系有 TL1a高表达小鼠诱导回肠炎症所需，野生型小鼠诱导正常PC所需 成熟和扩张。我们开发了一种新型的功能人体干细胞微工程芯片模型 PC，我们发现TL1A通过诱导溶菌酶颗粒扩散和无序而直接改变PC表型 黏膜高表达TL1a的SB CD中PC表型异常的形态学描述。 有证据表明未感染IBD的家系中血清IBD相关抗细菌抗体水平升高 IBD患者的成员以及在疾病临床证据之前的军队成员表明 宿主-细菌界面缺陷先于IBD的发病。对生物制品和疾病失去反应 复发可能代表疾病驱动细胞因子的消除，但不是潜在的过程。如果Pre- 炎症性PC异常可以通过操作TL1a来缓解/预防，它解决了 微生物-宿主界面，潜在的PC功能将重置，IBD可能在基因上先发制人 易感个体，组合还可以防止对现有治疗方法或 疾病复发。上述结果为研究TL1a驱动的机制提供了有力的理论基础 在促进SB炎症中PC的形态、成熟和功能的变化，使用我们的新小鼠 活体和人类干细胞体外系统，允许并行研究，以解析出细胞和 分子间同时相互作用。我们的调查将揭示更多的下游通道和 分子和潜在的联合治疗靶点。

PROJECT SUMMARY ABSTRACT Inflammatory bowel diseases (IBD) are chronic relapsing diseases of the gastrointestinal tract believed to be the result of complex interactions between genetic susceptibility and severity genes, the microbial environment, and a dysregulated innate and adaptive immune response against commensal micro-organisms. Paneth cells (PC) are specialized small bowel (SB) epithelial cells that constitutively produce anti-microbial proteins and are important in intestinal homeostasis. Abnormal PC morphology is observed in patients with Crohn’s disease (CD) and in mice with gene deletions in autophagy and unfolded protein response (UPR) pathways. Mice with PC-specific deletions in UPR and autophagy pathways develop early and severe SB inflammation. PC morphologic abnormalities precede onset of ileitis, implicating altered PC biology as central to the pathogenesis and severity of SB CD; yet the cell-extrinsic signals driving these abnormalities are undefined. TNFSF15/(TL1A) is an IBD susceptibility and severity locus and we have previously reported the relationship of a TNFSF15 risk genotype and increased expression of TL1A in peripheral monocytes and in non- inflamed SB CD. In translational studies, we also reported the association between this risk genotype and severe forms of SB CD including fibrostenosis that was phenocopied in mice overexpressing TL1A. We have found a significant association between TL1A and abnormal PC morphology. Commensal microbiota are required in TL1A-overexpressing mice to induce ileal inflammation and in wild type mice to induce normal PC maturation and expansion. We developed a novel stem cell micro-engineered chip model of functional human PC, we showed TL1A directly alters the PC phenotype by inducing diffused and disordered lysozyme granule morphology recapitulating the abnormal PC phenotypes in SB CD with high mucosal expression of TL1A. Evidence that serum levels of IBD-associated anti-bacterial antibodies are elevated in unaffected family members of patients with IBD and also in members of the military prior to clinical evidence of disease suggests defects in the host-bacterial interface precedes onset of IBD. Loss of response to biologics and disease recurrence may represent elimination of a disease driving cytokine but not the underlying process. If pre- inflammatory PC abnormality can be mitigated/prevented by manipulation of TL1A, which, addresses the microbial-host interface, potentially PC function will reset and IBD may be pre-empted in genetically susceptible individuals, and the combination may also prevent loss of response to existing therapeutics or disease recurrence. The foregoing provides a strong rationale for studying the mechanisms of TL1A-driven changes in PC morphology, maturation, and function in promoting SB inflammation, using our novel murine in vivo and human stem cell in vitro systems that allow for parallel investigations to parse out cellular and molecular interactions simultaneously. Our investigations will reveal additional downstream pathways and molecules and potentially targets for combination therapy.