Pathogenic Heterogeneity in Mucosal Stem Cells in Pediatric Crohn's Disease

描述 克罗恩病是一种非常普遍和侵袭性的炎症性肠病， 进展为需要手术干预的狭窄、瘘管和穿孔。强大 免疫抑制和抗炎治疗并没有改变对手术的依赖， 寻找针对这种疾病病因的治疗方法。遗传学和病理生理学的重大进展 在过去的十年中，已经清楚地确定克罗恩病和一般的炎症性肠病， 在肠道微生物的管理中，通过直接上皮衬里和先天性和 适应性免疫系统最近的全基因组关联研究（GWAS）支持了这一观点 除了预期的免疫调节基因外，还涉及到一个巨大的基因网络， 肠上皮细胞在我们理解肠上皮细胞在克罗恩病和其他疾病中的作用方面， 炎症性肠病一直缺乏强大的体外培养系统来测试上皮功能 与肠道炎症的混杂影响分开。我们现在已经开发出可靠的技术， 从人体胃肠道的每个区域克隆所谓的“基态”干细胞， 他们拥有与其起源一致的精确三维分化的表观遗传记忆和能力 尽管经过几个月的持续栽培同样的技术现在已经被用于从 克罗恩病患者的内镜活检。出乎意料的是，这些患者的活检结果显示出两种不同的 上皮干细胞群，包括与对照患者相同的上皮干细胞群和标记为 稳定的炎症基因标记和分泌细胞类型分化的严重缺陷。 值得注意的是，我们现在有强有力的初步证据表明，这两个属性的异常干细胞是 这是回肠末端细胞向近端肠细胞发生深刻的表观遗传转化的结果。 在三个具体目标中，我们将检验以下假设：1）这群异常干细胞赋予粘膜上皮细胞， 对微生物产物的超敏反应，2）分泌的趋化因子和细胞因子的组合产生 这些异常干细胞的作用足以促进粘膜中的炎症状态，和3）， 我们在克罗恩病中发现的异常干细胞代表了一种永久的和表观遗传学强制的开关， 末端回肠到近端肠状态，且随着超敏反应和 促炎表型我们预计，这些研究将提供新的见解，细胞生物学， 克罗恩氏病，粘膜干细胞异质性的作用，在病理相互作用之间的免疫 系统，微生物组和干预肠粘膜，并提供对潜在治疗的见解 目标是缓解这种疾病和炎症性肠病。

DESCRIPTION Crohn's disease is a remarkably prevalent and aggressive form of inflammatory bowel disease that often progresses to strictures, fistulas, and perforations requiring surgical intervention. Powerful immunosuppression and anti-inflammatory therapies have not altered the reliance on surgery, fueling the search for therapies that target the etiology of this condition. Major advances in genetics and pathophysiology in the past decade have now clearly established that Crohn's, and inflammatory bowel diseases in general, are pathologies in the management of gut microbes by the immediate epithelial lining and cells of the innate and adaptive immune system. Support for this notion comes from recent genome-wide association studies (GWAS) that, in addition to the expected immune regulatory genes, have implicated a vast network of genes linked to the intestinal epithelia. A major gap in our understanding the role of intestinal epithelia in Crohn's and other inflammatory bowel diseases has been the lack of robust in vitro cultivation systems to test epithelial function separate from confounding influences of the inflamed gut. We have now developed reliable technologies to clone so-called “ground state” stem cells from each region of the human gastrointestinal tract and have shown them to possess epigenetic memory of and capacity for precise 3-D differentiation consistent with their origins despite months of continuous cultivation. This same technology now has been used to capture stem cells from endoscopic biopsies of Crohn's patients. Unexpectedly, biopsies from these patients yield two distinct populations of epithelial stem cells including one identical to those of control patients and another marked by a stable inflammatory gene signature and profound defects in the differentiation of secretory cell types. Significantly, we now have strong preliminary evidence that these two properties of the aberrant stem cells are the result of a profound epigenetic transformation of cells of the terminal ileum to those of proximal intestine. In three specific aims, we will test hypotheses that 1) this population of aberrant stem cells confers a mucosal hypersensitivity to microbial products, 2) that the combination of secreted chemokines and cytokines produced by these aberrant stem cells is sufficient to promote an inflammatory state in the mucosa, and 3), that the aberrant stem cells we identified in Crohn's represent a permanent and epigenetically enforced switch from a terminal ileum to a proximal intestine state and along with that switch both the hypersensitivity and proinflammatory phenotypes. We anticipate that these studies will provide novel insights into the cell biology of Crohn's, the role of mucosal stem cell heterogeneity in the pathological interactions between the immune system, the microbiome, and the intervening intestinal mucosa, and provide insights into potential therapeutic targets for the mitigation of this and inflammatory bowel diseases in general.