Debugging the intestinal microbiota in IBD

Gut microbiota-based discriminative model for patients with ulcerative colitis: A meta-analysis and real-world study

Gut microbiota directly interacts with intestinal epithelium and is a significant factor in the pathogenesis of ulcerative colitis (UC). A meta-analysis was performed to investigate gut microbiota composition of patients with UC in the United States. We also collected fecal samples from Chinese patients with UC and healthy individuals. Gut microbiota was tested using 16S ribosomal RNA gene sequencing. Meta-analysis and 16S ribosomal RNA sequencing revealed significant differences in gut bacterial composition between UC patients and healthy subjects. The Chinese UC group had the highest scores for Firmicutes, Clostridia, Clostridiales, Streptococcaceae, and Blautia, while healthy cohort had the highest scores for P-Bacteroidetes, Bacteroidia, Bacteroidales, Prevotellaceae, and Prevotella_9. A gut microbiota-based discriminative model trained on an American cohort achieved a discrimination efficiency of 0.928 when applied to identify the Chinese UC cohort, resulting in a discrimination efficiency of 0.759. Additionally, a differentiation model was created based on gut microbiota of a Chinese cohort, resulting in an area under the receiver operating characteristic curve of 0.998. Next, we applied the model established for the Chinese UC cohort to analyze the American cohort. Our findings suggest that the diagnostic efficiency ranged from 0.8794 to 0.9497. Furthermore, a combined analysis using data from both the Chinese and US cohorts resulted in a model with a diagnostic efficacy of 0.896. In summary, we found significant differences in gut bacteria between UC individuals and healthy subjects. Notably, the model from the Chinese cohort performed better at diagnosing UC patients compared to healthy subjects. These results highlight the promise of personalized and region-specific approaches using gut microbiota data for UC diagnosis.

Long noncoding RNA expression profiles in gut tissues constitute molecular signatures that reflect the types of microbes

The gut microbiota is commonly referred to as a hidden organ due to its pivotal effects on host physiology, metabolism, nutrition and immunity. The gut microbes may be shaped by environmental and host genetic factors, and previous studies have focused on the roles of protein-coding genes. Here we show a link between long non-coding RNA (lncRNA) expression and gut microbes. By repurposing exon microarrays and comparing the lncRNA expression profiles between germ-free, conventional and different gnotobiotic mice, we revealed subgroups of lncRNAs that were specifically enriched in each condition. A nearest shrunken centroid methodology was applied to obtain lncRNA-based signatures to identify mice in different conditions. The lncRNA-based prediction model successfully identified different gnotobiotic mice from conventional and germ-free mice, and also discriminated mice harboring transplanted microbes from fecal samples of mice or zebra fishes. To achieve optimal prediction accuracy, fewer lncRNAs were required in the prediction model than protein-coding genes. Taken together, our study demonstrated the effecacy of lncRNA expression profiles in discriminating the types of microbes in the gut. These results also provide a resource of gut microbe-associated lncRNAs for the development of lncRNA biomarkers and the identification of functional lncRNAs in host-microbes interactions.

The intestinal microbiota and chronic disorders of the gut

Mucosal surfaces of the gut are colonized by large numbers of heterogeneous bacteria that contribute to intestinal health and disease. In genetically susceptible individuals, a 'pathogenic community' may arise, whereby abnormal gut flora contributes to alterations in the mucosa and local immune system leading to gastrointestinal disease. These diseases include enteric infections, such as Clostridium difficile infection, small intestinal bacterial overgrowth, functional gastrointestinal disorders (including IBS), IBD and colorectal cancer. Prebiotics, probiotics and synbiotics (a combination of prebiotics and probiotics) have the capacity to reverse pathologic changes in gut flora and local immunity. Intestinal health and disease need to be thoroughly characterized to understand the interplay between the indigenous microbiota, the immune system and genetic host factors. This Review provides a broad overview of the importance of the intestinal microbiota in chronic disorders of the gut.