D'Argenio Valeria, Casaburi Giorgio, Precone Vincenza, Pagliuca Chiara, Colicchio Roberta, Sarnataro Daniela, Discepolo Valentina, Kim Sangman M, Russo Ilaria, Del Vecchio Blanco Giovanna, Horner David S, Chiara Matteo, Pesole Graziano, Salvatore Paola, Monteleone Giovanni, Ciacci Carolina, Caporaso Gregory J, Jabrì Bana, Salvatore Francesco, Sacchetti Lucia
CEINGE-Biotecnologie Avanzate, Naples, Italy.
Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy.
Am J Gastroenterol. 2016 Jun;111(6):879-90. doi: 10.1038/ajg.2016.95. Epub 2016 Apr 5.
Celiac disease (CD)-associated duodenal dysbiosis has not yet been clearly defined, and the mechanisms by which CD-associated dysbiosis could concur to CD development or exacerbation are unknown. In this study, we analyzed the duodenal microbiome of CD patients.
The microbiome was evaluated in duodenal biopsy samples of 20 adult patients with active CD, 6 CD patients on a gluten-free diet, and 15 controls by DNA sequencing of 16S ribosomal RNA libraries. Bacterial species were cultured, isolated and identified by mass spectrometry. Isolated bacterial species were used to infect CaCo-2 cells, and to stimulate normal duodenal explants and cultured human and murine dendritic cells (DCs). Inflammatory markers and cytokines were evaluated by immunofluorescence and ELISA, respectively.
Proteobacteria was the most abundant and Firmicutes and Actinobacteria the least abundant phyla in the microbiome profiles of active CD patients. Members of the Neisseria genus (Betaproteobacteria class) were significantly more abundant in active CD patients than in the other two groups (P=0.03). Neisseria flavescens (CD-Nf) was the most abundant Neisseria species in active CD duodenum. Whole-genome sequencing of CD-Nf and control-Nf showed genetic diversity of the iron acquisition systems and of some hemoglobin-related genes. CD-Nf was able to escape the lysosomal compartment in CaCo-2 cells and to induce an inflammatory response in DCs and in ex-vivo mucosal explants.
Marked dysbiosis and an abundance of a peculiar CD-Nf strain characterize the duodenal microbiome in active CD patients thus suggesting that the CD-associated microbiota could contribute to the many inflammatory signals in this disorder.
乳糜泻（CD）相关的十二指肠微生物群失调尚未明确界定，且CD相关微生物群失调促进CD发生或加重的机制尚不清楚。在本研究中，我们分析了CD患者的十二指肠微生物组。
通过对16S核糖体RNA文库进行DNA测序，评估了20例成年活动性CD患者、6例采用无麸质饮食的CD患者以及15名对照者的十二指肠活检样本中的微生物组。通过质谱对细菌种类进行培养、分离和鉴定。将分离出的细菌种类用于感染Caco-2细胞，并刺激正常十二指肠外植体以及培养的人和小鼠树突状细胞（DC）。分别通过免疫荧光和酶联免疫吸附测定法评估炎症标志物和细胞因子。
在活动性CD患者的微生物组谱中，变形菌门最为丰富，而厚壁菌门和放线菌门最为稀少。奈瑟菌属（β-变形菌纲）的成员在活动性CD患者中比在其他两组中明显更为丰富（P = 0.03）。微黄奈瑟菌（CD-Nf）是活动性CD十二指肠中最丰富的奈瑟菌种类。对CD-Nf和对照-Nf进行全基因组测序显示，铁摄取系统和一些与血红蛋白相关的基因存在遗传多样性。CD-Nf能够在Caco-2细胞中逃离溶酶体区室，并在DC和离体黏膜外植体中诱导炎症反应。
明显的微生物群失调以及一种特殊的CD-Nf菌株的大量存在是活动性CD患者十二指肠微生物组的特征，这表明CD相关的微生物群可能促成了该疾病中的多种炎症信号。
