Antifungal immunity in Hirschsprung-Associated Enterocolitis

项目摘要 先天性巨结肠相关性小肠结肠炎（HAEC）是先天性巨结肠患儿最常见的并发症 疾病（HSCR），导致频繁住院和一半的死亡在这一人群中。的机制 对潜在的HAEC知之甚少。我们在一项微生物组研究中报告，念珠菌属。专门 在HAEC患者的粪便中富集，我们在这里报告HAEC患者具有升高的抗酵母菌 酿酒酵母抗体（ASCA）滴度。由于已知ASCA水平与炎症性肠病相关， 在研究鸡传染性法氏囊病（IBD）时，我们假设IBD的其他危险因素可能与HAEC相关。我们做了基因分型 单核苷酸多态性（SNPs）在一个小队列的HSCR患者，并发现初步证据 先前发现与IBD相关的37个SNP也可能与HAEC的发生风险有关。之一 这些基因，CARD 9，特别引起了我们的兴趣，因为CARD 9参与宿主免疫反应， 肠道微生物，特别是真菌，作为信号分子参与抗真菌C型凝集素受体 发信号。我们已经建立了HAEC的小鼠模型（Ednrb-null mouse model），并发现创建 Ednrb-Clec 7a双突变小鼠（Clec 7a基因编码抗真菌C型凝集素受体Dectin-1） 会导致粪便中的维生素C增加5倍。白色念珠菌和4倍增加小肠结肠炎的严重程度相比，对照组。 我们在Ednrb无效模型中进一步观察到产朊假丝酵母的自然肠道定植和 粘红酵母与发生HAEC的风险相关。最后，HAEC严重程度降低 65%，当动物用抗真菌药物艾沙康唑治疗时。总之，这些发现表明 HAEC涉及肠道真菌和抗真菌免疫的新机制。我们的总体假设是 对HAEC具有遗传易感性的HSCR患者对HAEC的变化反应不适当。 肠道微生物群（特别关注真菌）导致难以治疗的结肠炎。这一假设将 本研究的目的有两个：1）研究抗真菌免疫基因Card 9在小鼠体内的作用 HAEC模型; 2）确定产朊假丝酵母和粘红酵母在HAEC的相同小鼠模型中的作用。 港灯。这里概述的研究路线可能会导致使用以下药物治疗HAEC患者的更大合理性 个性化的方法，并可能导致用于早期识别处于发展高风险的患者的方法。 港灯。

PROJECT SUMMARY Hirschsprung associated enterocolitis (HAEC) is the most frequent complication in children with Hirschsprung disease (HSCR), resulting in frequent hospitalizations and half of deaths in this population. The mechanisms underlying HAEC are poorly understood. We reported in a microbiome study that Candida spp. are specifically enriched in stool of HAEC patients, and we report here that HAEC patients have elevated anti-Saccharomyces cerevisiae antibody (ASCA) titers. Since ASCA levels are known to be associated with inflammatory bowel disease (IBD), we hypothesized that other risk factors for IBD might be associated with HAEC. We genotyped single nucleotide polymorphisms (SNPs) in a small cohort of HSCR patients and found preliminary evidence that 37 SNPs previously found to associate with IBD may also be linked to the risk of developing HAEC. One of these genes, CARD9, particularly caught our interest because CARD9 is involved in host immune responses to intestinal microbes, especially fungi, as a signaling molecule involved in anti-fungal C-type lectin receptor signaling. We have established a mouse model of HAEC (Ednrb-null mouse model) and found that creating Ednrb-Clec7a double mutant mice (Clec7a gene encodes for the antifungal C-type lectin receptor Dectin-1) causes a 5-fold increase in fecal C. albicans and 4-fold increased enterocolitis severity compared with controls. We further observed in the Ednrb-null model that natural intestinal colonization with Candida utilis and Rhodotorula mucilaginosa is associated with the risk of developing HAEC. Finally, HAEC severity was reduced 65% when animals were treated with the antifungal drug isavuconazole. Together, these discoveries suggest new mechanisms for HAEC implicating intestinal fungi and antifungal immunity. Our overall hypothesis is that HSCR patients with genetic susceptibility to developing HAEC respond inappropriately to changes in the intestinal microbiota, (with a particular interest in fungi) leading to a difficult-to-treat colitis. This hypothesis will be investigated in the following two aims: 1) investigate the role of antifungal immunity gene Card9 in a mouse model of HAEC; 2) define the role of Candida utilis and Rhodotorula mucilaginosa in the same mouse model of HAEC. The line of investigation outlined here may lead to greater rationale for treating HAEC patients using personalized approaches and may lead to methods for early identification of patients at high risk of developing HAEC.