Project description:Mild or transient dietary restriction (DR) improves many aspects of health and aging. Emerging evidence from us and others has demonstrated that DR also optimizes the development and quality of immune responses. However, the factors and mechanisms involved remain to be elucidated. Here, we demonstrate that DR-induced optimization of immunological memory requires co-operation between memory T cells, the intestinal microbiota, and myeloid cells. Our data indicate that DR enhances the ability of memory T cells to recruit and activate myeloid cells in the context of a secondary infection. Concomitantly, DR promotes expansion of the commensal Bifidobacteria within the large intestine, which supplies the short-chain fatty acid acetate to myeloid cells. Acetate conditioning of the myeloid compartment during DR enhances their capacity to kill pathogens. Enhanced host protection during DR is abolished when Bifidobacteria expansion is prevented, indicating that microbiota configuration and function critically dictates immune responsiveness to this dietary intervention. Altogether, DR induces both memory T cells and the gut microbiota to produce essential, distinct factors that converge on myeloid cells to promote optimal pathogen control. These findings reveal how nutritional cues promote adaptation and co-operation between multiple immune cells and the gut microbiota, which synergize to optimize immunity and protect the collective metaorganism.
Project description:Mild or transient dietary restriction (DR) improves many aspects of health and aging. Emerging evidence from us and others has demonstrated that DR also optimizes the development and quality of immune responses. However, the factors and mechanisms involved remain to be elucidated. Here, we demonstrate that DR-induced optimization of immunological memory requires co-operation between memory T cells, the intestinal microbiota, and myeloid cells. Our data indicate that DR enhances the ability of memory T cells to recruit and activate myeloid cells in the context of a secondary infection. Concomitantly, DR promotes expansion of the commensal Bifidobacteria within the large intestine, which supplies the short-chain fatty acid acetate to myeloid cells. Acetate conditioning of the myeloid compartment during DR enhances their capacity to kill pathogens. Enhanced host protection during DR is abolished when Bifidobacteria expansion is prevented, indicating that microbiota configuration and function critically dictates immune responsiveness to this dietary intervention. Altogether, DR induces both memory T cells and the gut microbiota to produce essential, distinct factors that converge on myeloid cells to promote optimal pathogen control. These findings reveal how nutritional cues promote adaptation and co-operation between multiple immune cells and the gut microbiota, which synergize to optimize immunity and protect the collective metaorganism.
Project description:The exploration of microbial communities by sequencing 16S rRNA genes has expanded with low-cost, high-throughput sequencing instruments. Illumina-based 16S rRNA gene sequencing has recently gained popularity over 454 pyrosequencing due to its lower costs, higher accuracy and greater throughput. Although recent reports suggest that Illumina and 454 pyrosequencing provide similar beta diversity measures, it remains to be demonstrated that pre-existing 454 pyrosequencing workflows can transfer directly from 454 to Illumina MiSeq sequencing by simply changing the sequencing adapters of the primers. In this study, we modified 454 pyrosequencing primers targeting the V4-V5 hyper-variable regions of the 16S rRNA gene to be compatible with Illumina sequencers. Microbial communities from cows, humans, leeches, mice, sewage, and termites and a mock community were analyzed by 454 and MiSeq sequencing of the V4-V5 region and MiSeq sequencing of the V4 region. Our analysis revealed that reference-based OTU clustering alone introduced biases compared to de novo clustering, preventing certain taxa from being observed in some samples. Based on this we devised and recommend an analysis pipeline that includes read merging, contaminant filtering, and reference-based clustering followed by de novo OTU clustering, which produces diversity measures consistent with de novo OTU clustering analysis. Low levels of dataset contamination with Illumina sequencing were discovered that could affect analyses that require highly sensitive approaches. While moving to Illumina-based sequencing platforms promises to provide deeper insights into the breadth and function of microbial diversity, our results show that care must be taken to ensure that sequencing and processing artifacts do not obscure true microbial diversity.
Project description:Emerging data has highlighted the importance of short-chain fatty acids (SCFAs) on ruminal microbiome and derived metabolism profiling, and ruminal epithelial health and nutritional absorption in ruminants. However, little is known about the roles of SCFAs on hindgut profiles. Here, we firstly combined infusion of three SCFAs, to study their different roles in hindgut microbiome succession and derived metabolism profiling, as well as colonic epithelial transcriptome sequencing patterns using a in vivo goat model. .
Project description:Emerging data has highlighted the importance of short-chain fatty acids (SCFAs) on ruminal microbiome and derived metabolism profiling, and ruminal epithelial health and nutritional absorption in ruminants. However, little is known about the roles of SCFAs on ileal microbiome profiles. Here, we combined infusion of three SCFAs, to study their different roles in ileal microbiome succession profiling using a in vivo goat model.