Project description:The effect of oral microbiota on the intestinal microbiota has garnered growing attention as a mechanism linking periodontal diseases to systemic diseases. However, the salivary microbiota is diverse and comprises numerous bacteria with a largely similar composition in healthy individuals and periodontitis patients. Thus, the systemic effects of small differences in the oral microbiota are unclear. In this study, we explored how health-associated and periodontitis-associated salivary microbiota differently colonized the intestine and their subsequent systemic effects by analyzing the hepatic gene expression and serum metabolomic profiles. The salivary microbiota was collected from a healthy individual and a periodontitis patient and gavaged into C57BL/6NJcl[GF] mice. Samples were collected five weeks after administration. Gut microbial communities were analyzed by 16S ribosomal RNA gene sequencing. Hepatic gene expression profiles were analyzed using a DNA microarray and quantitative polymerase chain reaction. Serum metabolites were analyzed by capillary electrophoresis time-of-flight mass spectrometry. The gut microbial composition at the genus level was significantly different between periodontitis-associated microbiota-administered (PAO) and health-associated oral microbiota-administered (HAO) mice. The hepatic gene expression profile demonstrated a distinct pattern between the two groups, with higher expression of Neat1, Mt1, Mt2, and Spindlin1, which are involved in lipid and glucose metabolism. Disease-associated metabolites such as 2-hydroxyisobutyric acid and hydroxybenzoic acid were elevated in PAO mice. These metabolites were significantly correlated with Bifidobacterium, Atomobium, Campylobacter, and Haemophilus, which are characteristic taxa in PAO mice. Conversely, health-associated oral microbiota were associated with higher levels of beneficial serum metabolites in HAO mice. The multi-omics approach used in this study revealed that periodontitis-associated oral microbiota is associated with the induction of disease phenotype when they colonized the gut of germ-free mice.
Project description:The role of gut microbiota dysbiosis in systemic lupus erythematosus (SLE) pathogenesis remains elusive. Here, we show that fecal microbiota transplantation (FMT) from healthy mice to lupus mice ameliorated lupus-like symptoms. Microbiota reconstitution effectively reduced systemic class switch recombination and elevated IGH naïve isotype. Microbiota profiling revealed an enrichment of Lactobacillus johnsonii post-FMT, with a significant correlation to purine metabolites. Importantly, the Lactobacillus johnsonii-derived inosine, an intermediate metabolite in purine metabolism, effectively alleviated lupus-like symptoms by impeding B cell differentiation and reducing renal B cell infiltration. We further demonstrated that inosine reprograms B cells through the ERK-HIF-1α signaling pathway. Overall, our study highlights the discovery of a novel microbial metabolite modulating autoimmunity and suggests its potential for innovative microbiome-based therapeutic approaches.
Project description:Systemic sclerosis (SSc) is a complex and still unclear rare disease associated with fibrosis in multiple organs. Microbiota has recently emerged as an important environmental factor in SSc pathogenesis, either at gut, oral and skin level.