Project description:P. bryantii B14 cells were cultivated separately in acetic (Acet), propionic (Prop), butyric (But), iso-butyric (iBut), valeric (Val), iso-valeric (iVal) and 2-methyl butyric acid (2MB) as well as in a mixture of all mentioned short-chain fatty acids (Mix). All 8 treatments were analyzed regarding their proteomes in order to understand the requirements and effects of each SCFA on the metabolism.
Project description:Angiopoietin-like protein 4 (ANGPTL4, also referred to as Fiaf) has been proposed as circulating mediator between the gut microbiota and fat storage in adipose tissue. Very little is known about mechanisms of regulation of ANGPTL4 in the colon. Here we show that transcription and subsequent secretion of ANGPTL4 in human T84 and HT-29 colonocytes is highly induced by physiological concentrations of products of bacterial fermentation, the short chain fatty acids (SCFA). Induction of ANGPTL4 by SCFA cannot be mimicked by the histone deacetylase inhibitor Trichostatin A. SCFA induce ANGPTL4 by activating the nuclear receptor PPARγ, as shown by use of PPARγ antagonist, PPARγ knock-down, and transactivation assay, which shows activation of PPARγ but not PPARα and PPARδ. At concentrations required for PPARγ activation and ANGPTL4 induction in colonocytes, SCFA do not stimulate PPARγ in mouse 3T3-L1 and human SGBS adipocytes, suggesting that SCFA act as selective PPARγ modulators (SPPARM), which is supported by coactivator peptide recruitment assay and structural modelling. Consistent with the notion that fermentation leads to PPAR activation in vivo, feeding mice a diet rich in inulin was associated with induction of PPAR target genes and pathways in the colon, as shown by microarray and subsequent gene set enrichment analysis. It can be concluded that 1) SCFA potently stimulate ANGPTL4 synthesis in human colonocytes; 2) SCFA transactivate and bind to PPARγ by serving as selective PPAR modulators. Our data point to activation of PPARγ as a novel mechanism of gene regulation by SCFA in the colon.
Project description:This is to determine the regulation of gene expression in different T Cell population with short chain fatty acids. This will provide the roles of SCFAs in regulation of adaptive immunity and T-cell-mediated inflammation.
Project description:Objective: To study the effects of Short Chain Fatty Acids (SCFAs) on arthritic bone remodeling. Methods: We treated a recently described preclinical murine model of psoriatic arthritis (PsA), R26STAT3Cstopfl/fl CD4Cre mice, with SCFA supplemented water. We also performed in vitro osteoclast differentiation assays in the presence of serum-level SCFAs to evaluate the direct impact of these microbial metabolites on maturation and function of osteoclasts. We further characterized the molecular mechanism of SCFAs by bulk transcriptomics analysis. Results: The osteoporosis condition in R26STAT3Cstopfl/fl CD4Cre animals is attributed primarily to an expansion of osteoclast progenitor cells (OCPs), leading to robust osteoclast differentiation. We show that SCFA supplementation can rescue the osteoporosis phenotype in this model of PsA. Our in vitro experiments revealed an inhibitory effect of the SCFAs on osteoclast differentiation, even at very low serum concentrations. This suppression of osteoclast differentiation enabled SCFAs to impede osteoporosis development in R26STAT3Cstopfl/fl CD4Cre mice. Further interrogation revealed that bone marrow derived OCPs from diseased mice expressed a higher level of SCFA receptors than that of control mice and that the progenitor cells in the bone marrow of SCFA-treated mice presented a modified transcriptomic landscape, suggesting a direct impact by SCFAs on osteoclast progenitors. Conclusion: We demonstrated how gut microbiota-derived SCFAs can regulate distal pathology, i.e., osteoporosis, and identified a potential therapeutic option for restoring bone density in rheumatic disease, further highlighting the critical role of the gut-bone axis in these disorders.
Project description:Enterohaemorrhagic Escherichia coli (EHEC) is an emerging pathogen that causes diarrhea and heamolytic uremic syndrome. Expression of genes associated to pathogenicity is strictly regulated by environmental factors. Since short chian fatty acids (SCFAs) are present in intestinal tract which is a target of EHEC infection, we investigated the response of EHEC genes to SCFAs, such as acetate, propionate and butyrate. Keywords: Culture condition 3 sets of comparison between transcription profiles in EHEC growing in the presence of acetate, propionate or butyrate against EHEC growing in the presence of NaCl. Labelling of cDNA and hybridization were performed twice with independently prepared RNAs.