| Objective: Crohn’s disease(CD)is a chronic recurrent nonspecific intestinal inflammatory disease.Gut microbiota imbalance and metabolic disorders are closely related to the pathogenesis of CD.The study of CD gut microbial ecosystem is presently concentrated in European and American countries.The incidence rate of CD in China is quite different from that in European and American countries.There is no systematic report on Chinese CD patients’ intestinal flora and metabolic characteristics.This study aimed to explore the gut microecological characteristics of Chinese CD patients using multinomial methods.Methods: CD patients and healthy controls from the health management center in the Third Xiangya Hospital of Central South University from October 2019 to October 2020 were recruited.LC-MS/MS and GC-MS methods were used to detect the targeted metabolomics of serum and fecal metabolites in all subjects.Metagenomic sequencing was used to analyze the structure and composition of gut microbiota in all subjects.Metaproteomics sequencing was used to analyze the expression of gut microbiota proteins in all subjects.The canonical sparse model was used to screen the key metabolites and strains.Correlation analysis,network diagram,and sankey analysis were used to evaluate the relationship between the groups.Results: 30 CD patients and 30 healthy controls were recruited.Among the patients with CD,24 males and six females,ranging in age from 19 to 70 years,and 12 were in the active stage.A total of 58 different metabolites were screened by fecal metabonomics.Compared with healthy people,primary bile acids,unsaturated fatty acids,amino acids and their derivatives,trace amines,and TMAO-related metabolites in the feces of CD patients were significantly increased,while short-chain fatty acids,secondary bile acids,and 5-aminolevulinic acid were significantly decreased.A total of 32 different metabolites were screened by blood metabolomics,most of which had no solid direct correlation between blood and feces.Metastatic analysis of metagenomics showed significant abundance differences between CD and healthy populations in 175 genera and 2435 species.Based on lefse analysis,91 differential classifications can be obtained.The groups with the highest enrichment in the fecal microbial community of the CD group are Enterobacteriaceae,Proteobacteria,Fusobacteria,Enterococcus,Escherichia coli,and [Ruminococcus]gnavus and Klebsiella pneumoniae.In contrast,the healthy control group was rich in Firmicutes,Eubacterium,Ruminococcus,Roseburia,Dorea,Faecalibacterium,and Faecalibacterium prausnitzii.Fecal Metaproteomics analysis showed that 518 proteins were significantly different between CD patients and healthy controls and were related to amino acid metabolism,degradation,synthesis,fat digestion and absorption,coenzyme synthesis,and other metabolic pathways.Thirteen key metabolites and ten key strains were screened based on the regularized sparse model.PCA analysis and ROC curve analysis showed that it had a solid ability to distinguish between CD and healthy people.Spearman correlation analysis showed that different metabolites were associated with essential taxa.Multiomics network diagram analysis showed butyric acid,methylmalonic acid,5-aminolevulinic acid(5-ALA),Coprococcus catus,Alispes putredinis,and large subunit ribosomal protein L3 played a crucial role in microbiota imbalance and metabolic disorder.The species and function annotation of metagenome combined with metaproteomics suggest that Coprococcus catus has three synthetase synthetases that produce 5-ALA,suggesting that Coprococcus catus may be an essential strain regulating 5-ALA metabolism in the intestine.Conclusion: the gut microbiota of patients with Crohn’s disease in China is disordered.The results show that the characteristics of this disorder are the decrease in microbiota diversity,the decrease in the abundance of beneficial bacteria,and the change in the composition and distribution of fecal metabolites.Biomarkers based on fecal microbiome and metabolome can distinguish CD patients from healthy controls.The abnormal metabolism of butyric acid and 5-ALA plays a vital role in the flora imbalance and is expected to become a potential therapeutic target.The decrease of Coprococcus catus abundance in the CD intestine may be an important reason for the decrease of 5-ALA.9 figures,1 table,128 references... |
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