Project description:Acetate, propionate and butyrate are the main short-chain fatty acids (SCFAs) that arise from the fermentation of fibers by the colonic microbiota. While many studies focus on the regulatory role of SCFAs, their quantitative role as a catabolic or anabolic substrate for the host has received relatively little attention. To investigate this aspect, we infused conscious mice with physiological quantities of stable isotopes [1-13C]acetate, [2-13C]propionate or [2,4-13C2]butyrate directly into the cecum, which is the natural production site in mice, and analyzed their interconversion by the microbiota as well as their metabolism by the host. Cecal interconversion - pointing to microbial cross-feeding - was high between acetate and butyrate, low between butyrate and propionate and almost absent between acetate and propionate. As much as 62% of infused propionate was used in whole-body glucose production, in line with its role as gluconeogenic substrate. Conversely, glucose synthesis from propionate accounted for 69% of total glucose production. The synthesis of palmitate and cholesterol in the liver was high from cecal acetate (2.8% and 0.7%, respectively) and butyrate (2.7% and 0.9%, respectively) as substrates, but low or absent from propionate (0.6% and 0.0%, respectively). Label incorporation due to chain elongation of stearate was approximately 8-fold higher than de novo synthesis of stearate. Microarray data suggested that SCFAs exert only a mild regulatory effect on the expression of genes involved in hepatic metabolic pathways during the 6h infusion period. Altogether, gut-derived acetate, propionate and butyrate play important roles as substrates for glucose, cholesterol and lipid metabolism. Mice were infused in cecum with stably-labelled isotopes of the three main short chain fatty acids or control solution. After 6 hrs, livers were removed and pooled RNA samples were subjected to gene expression profiling.
Project description:Intervention group:High flavonoid content fruit and vegetable diet guidance;Control group:No
Primary outcome(s): Flavonoid markers;Salivary cortisol;Blood cortisol;Gut microbiota;Mental Health Assessment Questionnaire;Fecal short chain fatty acids;Changes in defecation habits and traits
Study Design: Parallel
Project description:Insulin secretion by pancreatic b-cells is primarily regulated by glucose; however, hormones and additional nutrients, such as long-chain fatty acids, also play an important role in adjusting insulin output to physiologic needs. We examined the role of the short chain fatty acid receptor, GPR41, in funcion of pancreatic beta cells. GPR41 was specifically over-expressed in beta cells by using rat insulin promoter II (41 Tg).
Project description:This transcriptomic study investigates the effect of therapeutic short-chain fatty acids (SCFA) administration on post-stroke recovery.
2020-01-01 | GSE131788 | GEO
Project description:Short-Chain Fatty Acids Modulate Microbiota Composition and Functional Potential
Project description:Objective: An altered gut bacterial composition is associated with the pathogenesis of type 1 diabetes and short-chain fatty acids are known to play a pivotal role in maintaining gut homeostasis. The effects of short-chain fatty acids on pancreatic islet cell function, insulin production and local immune-infiltration, however, remain elusive.Methods: Five-week-old female NOD mice were fed with an acetylated and butyrylated high-amylose maize-resistant starch (HAMSAB) or control diet for five consecutive weeks. The pancreata were harvested, islets isolated using collagenase, and dispersed into single cells by trypsin. Single-cell RNA sequencing was performed with 10x Chromium. The raw counts were analysed using RStudio with the Seurat package. Human embryonic stem cell-differentiated beta-like cells, mouse islets and INS-1E beta cell line were treated with acetate, butyrate and/or combination. Pro-inflammatory cytokines (IFN- + IL-1) were used for stress response and viability assays. Results: single-cell RNA sequencing analysis mapped the gene expression profiles of 4,301 and 4,113 individual islet cells from HAMSAB or HAMS fed mice, respectively. Cells were annotated into 11 clusters: 5 immune, 4 endocrine, acinar and endothelial cell types. The scRNA seq dataset indicated that T cells, B cells, macrophages, and dendritic cell subsets infiltrated the islets of Langerhans from both HAMSAB and HAMS-fed mice. Interestingly, HAMSAB induced an immune tolerogenic profile and lower cytotoxic Gzma+ CD8+ T cells. Moreover, HAMSAB maintained the expression of beta cell functional genes (i.e., Ins1, Ins2, G6pc2, Prlr and Iapp) and decreased the expression of genes associated with cellular stress (i.e., Fos, Impact, Stat1, Dusp1 and Hsp40/Dnajb1). Short-chain fatty acid treatment decreased pro-inflammatory cytokine-induced stress in mouse islets and INS-1E beta cells. In addition, HAMSAB preserved the identity of endocrine cells, evaluated by a decrease in dedifferentiated poly-hormonal cells expressing endocrine progenitor genes (MafA, Nfix). Importantly, short-chain fatty acids increased insulin levels in human embryonic stem cell-differentiated beta-like cells and improve transplantation outcome in NOD/SCID mice. Conclusions: Short-chain fatty acids prevent diabetes development in NOD mice, at least in part, by enhancing beta cell function and preserving the cell identity of endocrine cells under inflammatory-mediated autoimmune stress.