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，通常 进展为狭窄、瘘管和穿孔，需要手术治疗。功能强大 免疫抑制和抗炎治疗并没有改变对手术的依赖，助长了 寻找针对这种情况的病因的治疗方法。遗传学和病理生理学的主要进展 在过去的十年中，现在已经清楚地证实，克罗恩氏症和一般的炎症性肠病 肠道微生物的直接上皮衬里和天然和天然细胞管理中的病理学 适应性免疫系统。对这一概念的支持来自最近的全基因组关联研究(GWAS) 除了预期的免疫调节基因，这还牵涉到一个庞大的基因网络，这些基因与 肠道上皮细胞。我们对肠上皮细胞在克罗恩病和其他疾病中的作用的理解上的一个主要差距 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 与发炎的肠道的混杂影响分开。我们现在已经开发了可靠的技术来 从人类胃肠道的每个区域克隆了所谓的“基态”干细胞，并展示了 他们拥有与他们的起源一致的表观遗传记忆和精确的三维分化能力 尽管连续培养了几个月。同样的技术现在已经被用来从 克罗恩病患者的内窥镜活检。出乎意料的是，这些患者的活组织检查产生了两种截然不同的 上皮干细胞群体包括一个与对照组患者相同的群体，另一个具有明显的 稳定的炎性基因特征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，异常干细胞的这两个特性是 回肠末端细胞向近端肠道细胞深刻的表观遗传转化的结果。 在三个特定的目标中，我们将测试假设：1)这种变异的干细胞群体提供了一种粘膜 对微生物产品的过敏性，2)分泌的趋化因子和细胞因子的组合产生 这些变异的干细胞足以促进粘膜的炎症状态，以及3)， 我们在克罗恩氏症中发现的异常干细胞代表着一种永久性的表观遗传学转换 末端回肠到近端肠道状态，并伴随着该开关 致炎表型。我们预计，这些研究将为人类的细胞生物学提供新的见解。 克罗恩病，粘膜干细胞异质性在免疫之间病理相互作用中的作用 系统、微生物组和介入性肠粘膜，并提供对潜在治疗方法的见解 减轻这一疾病和一般炎症性肠病的目标。

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.