CFTR modulates innate immune response in biliary epithelium: Role in the pathogenesis and treatment of Cystic-Fibrosis-related liver disease.

摘要 囊性纤维化是一种常见的、临床上严重的遗传病，由CFTR1基因突变引起。 一种膜蛋白，在许多分泌上皮细胞中调节氯化物和液体的分泌，包括 胆汁树。囊性纤维化肝病(CFLD)是一种慢性胆管病，最终可能演变为 硬化性胆管炎和局限性胆汁性肝硬变。这种情况的发病机制尚不清楚， 治疗仅限于给予胆汁酸，或在某些情况下，肝移植。 CFLD被经典地认为是由胆汁分泌受损引起的后果 CFTR通道功能有缺陷。然而，尽管慢性萎缩性胃炎的胆汁分泌普遍减少，但 CFLD的自发发展较少发生，这表明遗传和/或获得性因素在 玩。我们先前的研究表明，胆道天然免疫系统对内毒素的耐受性降低 在CFLD中起主要致病作用。我们发现从CFTR-KO小鼠分离的胆管细胞具有 当暴露于TLR4配体时，更高的NF-κB活性和分泌更多的炎性细胞因子 LP。我们还证明，在CF缺陷的胆管细胞中，TLR4被不受抑制的 Src家族激酶(SFK)的功能，是CFTR缺陷的结果。这种机制也存在于 ΔF508突变纯合子来源的人肝内胆管细胞。此外，新奇刺激 初步数据显示，CFTR-KO小鼠出生时的肠道微生物区系已经与WT产仔不同 而且它偏向于更有利于炎症的细菌的盛行。 在本应用程序中，我们将测试CFLD可能是由基因组合导致的假设 突变对胆管上皮天然免疫的影响以及微生物区系组成和 肠道通透性增加。特别是，(1)我们将使用IPSC技术来剖析 人类致炎表型机制上不同功能的CFTR突变 和(2)我们将研究肠道微生物区系的变化是否在 肝纤维化小鼠模型的肝病进展。 我们的研究将发现分泌上皮生理和先天免疫的新方面，如果 肠道微生物区系的变化可能在CFLD中起着因果作用。这些研究代表着一个范式的转变 对CFLD发病机制的认识和启示CFLD的治疗也应控制 炎症和肠道微生物区系的影响。该项目的成果将为 新的干预策略将对CFLD和其他胆管疾病的管理产生影响。 好了！

SUMMARY Cystic Fibrosis (CF) is a common and clinically severe genetic disease, caused by mutations in CFTR, a membrane protein that mediates chloride and fluid secretion in a number of secretory epithelia, including the biliary tree. Cystic Fibrosis liver disease (CFLD) is a chronic cholangiopathy that can eventually evolve into sclerosing cholangitis and focal biliary cirrhosis. The pathogenesis of this condition is not well understood and treatment is limited to the administration of choleretic bile acids, or in selected cases, liver transplantation. CFLD has been classically considered a consequence of the impaired bile secretion caused by the defective CFTR channel function. However, while biliary secretion is universally reduced in CF, the spontaneous development of CFLD is less frequent, suggesting that genetic and/or acquired factors are at play. Our previous studies suggested that reduced tolerance of the biliary innate immune system to endotoxins plays a major pathogenetic role in CFLD. We showed that cholangiocytes isolated from Cftr-KO mice have higher NF-κB activity and secrete a larger amount of inflammatory cytokines, when exposed to the TLR4-ligand LPS. We have also demonstrated that in CF-defective cholangiocytes, TLR4 is activated by the unrestrained function of Src family kinases (SFK), a consequence of defective CFTR. This mechanism is present also in cholangiocytes derived from human iPSC homozygous for the ΔF508 mutation. In addition, novel exciting preliminary data show that the gut microbiota in CFTR-KO mice is already different from WT littermates at birth and it is skewed towards the prevalence of a more pro-inflammatory flora. In this application we will test the hypothesis that CFLD may result from the combination of a genetic mutation affecting biliary epithelial innate immunity along with changes in microbiota composition and increased intestinal permeability. In particular, (1) we will use iPSC technology to dissect the impact of functionally different CFTR mutations on the mechanisms leading to a pro-inflammatory phenotype in human cholangiocytes and (2) we will study whether changes in the gut microbiota play a causal role in the development of liver disease in mouse models of CF. Our study will discover novel aspects of secretory epithelia physiology and innate immunity and clarity if changes in the gut microbiota play a possible causal role in CFLD. These studies represent a paradigm-shift in the understanding of the pathogenesis of CFLD and imply that treatment for CFLD should also control inflammation and the impact of the intestinal microbiota. The outcome of this project will lay the foundation for novel intervention strategies that will have an impact on the management of CFLD and other cholangiopathies. !