The effect of short-chain fatty acids on human monocyte-derived dendritic cells.
ABSTRACT: The gut microbiota is essential for human health and plays an important role in the pathogenesis of several diseases. Short-chain fatty acids (SCFA), such as acetate, butyrate and propionate, are end-products of microbial fermentation of macronutrients that distribute systemically via the blood. The aim of this study was to investigate the transcriptional response of immature and LPS-matured human monocyte-derived DC to SCFA. Our data revealed distinct effects exerted by each individual SCFA on gene expression in human monocyte-derived DC, especially in the mature ones. Acetate only exerted negligible effects, while both butyrate and propionate strongly modulated gene expression in both immature and mature human monocyte-derived DC. An Ingenuity pathway analysis based on the differentially expressed genes suggested that propionate and butyrate modulate leukocyte trafficking, as SCFA strongly reduced the release of several pro-inflammatory chemokines including CCL3, CCL4, CCL5, CXCL9, CXCL10, and CXCL11. Additionally, butyrate and propionate inhibited the expression of lipopolysaccharide (LPS)-induced cytokines such as IL-6 and IL-12p40 showing a strong anti-inflammatory effect. This work illustrates that bacterial metabolites far from the site of their production can differentially modulate the inflammatory response and generally provides new insights into host-microbiome interactions.
Project description:We investigated the influence of SCFAs on human, monocyte derived DCs that represent a reliable in vitro model to study circulating DCs, one of the key regulators of our immune system. We studied the individual effect exerted by SCFA, the main metabolic end-products of fermentation by anaerobic bacteria in the gut, on the gene expression of immature and mature DC, exploring the potential of circulating bacterial metabolites to directly influence immune system cells. We found that SCFAs have little effect on the transcriptome of immature DC, whereas the transcriptome of mature DC was highly perturbed especially by butyrate and propionate. Our findings show an overall down-regulation of LPS-induced inflammatory responses and provide new insights into host-microbiome interactions. In this dataset, we include the expression data obtained from immature and matured (via lipopolysaccharide, LPS) human monocyte-derived dendritic cells untreated and treated with 1mM of acetate, butyrate, or propionate.
Project description:Background and Aim: Endothelial activation is characterized by excessive production of cytokines and chemokines as well as adhesion molecules expression which is involved in the development of atherosclerosis. The aim of our study is to investigate the effects of short chain fatty acids (SCFA) on lipopolysaccharide (LPS) or tumor necrosis factor alpha (TNF?)-induced endothelial activation. Methods and Results: Human umbilical vein endothelial cells (HUVEC) were pre-treated with acetate (10 mM), butyrate (0.1 mM) or propionate (0.3 mM) for 1, 16, or 24 h and then stimulated with LPS (1 or 10 ?g/ml) or TNF? (100 pg/ml or 1 ng/ml) for 6, 12, or 24 h. Cytokines in the supernatant were measured by ELISA. HUVEC were pre-treated with acetate (10 mM), butyrate (5 mM) or propionate (10 mM) for 24 h and then stimulated with LPS (1 ?g/ml) or TNF? (1 ng/ml) for 8 h. The expression of the adhesion molecules intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) was detected by flow cytometry. The human blood mononuclear cell adhesive level to HUVEC monolayer was measured. LPS and TNF? induced a significant increase in the release of interleukin-6 (IL-6) and IL-8. Acetate, butyrate and propionate reduced IL-6 and IL-8 levels and the magnitude was dependent on the incubation times. LPS or TNF? increased ICAM-1 and VCAM-1 expression. Pre-incubation with acetate had no effect. In contrast, butyrate and propionate decreased VCAM-1 expression in TNF? stimulated cells but showed no effects on ICAM-1 expression. Butyrate significantly inhibited the adhesion of mononuclear cells to an endothelial monolayer and propionate was less effective. Conclusion: SCFA, including acetate, butyrate and propionate, influenced LPS- or TNF?-induced endothelial activation by inhibiting the production of IL-6 and IL-8, and reducing the expression of VCAM-1 and subsequent cell adhesion. Results were dependent on the concentrations and pre-incubation time of each SCFA and stimulation time of LPS or TNF?.
Project description:Background and Aim: Previously, we found that short chain fatty acids (SCFA) inhibit LPS or TNF?-induced endothelial inflammatory responses and excessive vascular cell adhesion molecule-1 (VCAM-1) expression, two important steps in the development of atherosclerosis. However, the mechanisms involved are still unclear. We hypothesized that the effects of SCFA are associated with activation of G-protein coupled receptor 41/43 (GPR41/43) and/or inhibition of histone deacetylases (HDACs). Methods: The expression and location of GPR41/43 and HDAC3 in human umbilical vein endothelial cells (HUVEC) were confirmed. HUVEC were pre-incubated with acetate, butyrate or propionate alone or in combination with GLPG0974 (GLPG, antagonist of GPR43) or ?-hydroxybutyrate (SHB, antagonist of GPR41) and then exposed to LPS or TNF?. Interleukin (IL)-6 and IL-8 levels and VCAM-1 expression were measured. HDAC activity was measured after treatment with butyrate, propionate and trichostatin A (TSA, HDAC inhibitor). The peripheral blood mononuclear cell (PBMC) adhesive level was also determined after TSA treatment. Results: GPR41/43 were expressed on the membrane of HUVEC and HDAC3 was located in cytoplasm and nucleus. The GLPG and/or SHB treatments restored the inhibitory effects of acetate on IL-6 and IL-8 production and the inhibitory effects of butyrate or propionate on IL-6 production, but not on IL-8. In contrast, GLPG and/or SHB treatments did not affect the inhibitory effects of butyrate or propionate on TNF?-induced VCAM-1 expression. TSA showed similar effects on IL-8 production and VCAM-1 expression as butyrate and propionate. In addition, TSA significantly inhibited the adhesion of PBMC to an endothelial monolayer. Conclusion: Activation of GPR41/43 mediates the effects of acetate on IL-6 and IL-8 production and the effects of butyrate and propionate on IL-6 production. Furthermore, inhibition of HDACs mediates the effects of butyrate and propionate on IL-8 production, VCAM-1 expression, and PBMC adhesion to an endothelial monolayer. These data indicate the beneficial roles of SCFA in preventing vascular inflammation and relevant diseases by activation of GPR41/43 and inhibition of HDACs.
Project description:Short chain fatty acids (SCFA), including acetate, propionate, and butyrate, are produced during bacterial fermentation of undigested carbohydrates in the human colon. In this study, we applied a stable-isotope dilution method to quantify the in vivo colonic production of SCFA in healthy humans after consumption of inulin. Twelve healthy subjects performed a test day during which a primed continuous intravenous infusion with [1-(13)C]acetate, [1-(13)C]propionate and [1-(13)C]butyrate (12, 1.2 and 0.6 ?mol·kg(-1)·min(-1), respectively) was applied. They consumed 15 g of inulin with a standard breakfast. Breath and blood samples were collected at regular times during the day over a 12 h period. The endogenous rate of appearance of acetate, propionate, and butyrate was 13.3 ± 4.8, 0.27 ± 0.09, and 0.28 ± 0.12 ?mol·kg(-1)·min(-1), respectively. Colonic inulin fermentation was estimated to be 137 ± 75 mmol acetate, 11 ± 9 mmol propionate, and 20 ± 17 mmol butyrate over 12 h, assuming that 40%, 10%, and 5% of colonic derived acetate, propionate, and butyrate enter the systemic circulation. In conclusion, inulin is mainly fermented into acetate and, to lesser extents, into butyrate and propionate. Stable isotope technology allows quantifying the production of the three main SCFA in vivo and proved to be a practical tool to investigate the extent and pattern of SCFA production.
Project description:The early and accurate prediction of the hepatotoxicity of new drug targets during nonclinical drug development is important to avoid postmarketing drug withdrawals and late-stage failures. We previously established long-term expandable and functional human-induced pluripotent stem cell (iPSC)-derived liver organoids as an alternative source for primary human hepatocytes. However, PSC-derived organoids are known to present immature fetal characteristics. Here, we treated these liver organoids with microbial short-chain fatty acids (SCFAs) to improve metabolic maturation based on microenvironmental changes in the liver during postnatal development. The effects of the three main SCFA components (acetate, propionate, and butyrate) and their mixture on liver organoids were determined. Propionate (1 µM) significantly promoted the <i>CYP3A4</i>/<i>CYP3A7</i> expression ratio, and acetate (1 µM), propionate (1 µM), and butyrate (1 µM) combination treatment, compared to no treatment (control), substantially increased CYP3A4 activity and albumin secretion, as well as gene expression. More importantly, mixed SCFA treatment accurately revealed troglitazone-induced hepatotoxicity, which was redeemed on a potent CYP3A4 inhibitor ketoconazole treatment. Overall, we determined, for the first time, that SCFA mixture treatment might contribute to the accurate evaluation of the CYP3A4-dependent drug toxicity by improving metabolic activation, including CYP3A4 expression, of liver organoids.
Project description:Gut-derived short-chain fatty acids (SCFA), formed by microbial fermentation of dietary fibers, are believed to be involved in the etiology of obesity and diabetes. Previous data from our group showed that colonic infusions of physiologically relevant SCFA mixtures attenuated whole-body lipolysis in overweight men. To further study potential mechanisms involved in the antilipolytic properties of SCFA, we aimed to investigate the in vitro effects of SCFA incubations on intracellular lipolysis and signaling using a human white adipocyte model, the human multipotent adipose tissue-derived stem (hMADS) cells.hMADS adipocytes were incubated with mixtures of acetate, propionate, and butyrate or single SCFA (acetate, propionate and butyrate) in concentrations ranging between 1?µmol/L and 1?mmol/L. Glycerol release and lipase activation was investigated during basal conditions and following ?-adrenergic stimulation.SCFA mixtures high in acetate and propionate decreased basal glycerol release, when compared to control (P?<?0.05), while mixtures high in butyrate had no effect. Also, ?-adrenergic receptor mediated glycerol release was not significantly altered following incubation with SCFA mixtures. Incubation with only acetate decreased basal (1?µmol/L) and ?-adrenergically (1?µmol/L and 1?mmol/L) mediated glycerol release when compared with control (P?<?0.05). In contrast, butyrate (1?µmol/L) slightly increased basal and ?-adrenergically mediated glycerol release compared with control (P?<?0.05), while propionate had no effect on lipolysis. The antilipolytic effect of acetate was accompanied by a reduced phosphorylation of hormone-sensitive lipase (HSL) at serine residue 650. In addition, inhibition of Gi G proteins following pertussis toxin treatment prevented the antilipolytic effect of acetate.The present data demonstrated that acetate was mainly responsible for the antilipolytic effects of SCFA and acts via attenuation of HSL phosphorylation in a Gi-coupled manner in hMADS adipocytes. Therefore, the modulation of colonic and circulating acetate may be an important target to modulate human adipose tissue lipid metabolism.
Project description:The metabolic requirements change during cell proliferation and differentiation. Upon antigen-stimulation, effector T cells switch from adenosine-triphospate (ATP)-production by oxidative phosphorylation in the mitochondria to glycolysis. In the gut it was shown that short chain fatty acids (SCFA), fermentation products of the microbiota in colon, ameliorate inflammatory reactions by supporting the differentiation of regulatory T cells. SCFA are a major energy source, but they are also anabolic metabolites, histone-deacetylase-inhibitors and activators of G protein receptors. Recently, it was reported that a topical application of the SCFA butyrate promotes regulatory T cells in the skin. Here we ask if the SCFA butyrate, propionate and acetate affect the energy metabolism and inflammatory potential of dendritic epidermal T cells (DETC), the innate resident skin γδ T cell population. Using the Seahorse™ technology, we measured glycolysis and oxidative phosphorylation (OXPHOS) in a murine DETC cell line, 7-17, upon TCR-stimulation by CD3/CD28 crosslinking, with or without SCFA addition. TCR engagement resulted in a change of the ratio glycolysis/OXPHOS. A similar metabolic shift has been described for activated CD4 T cells. Addition of 5 mM SCFA, in particular butyrate, antagonized the effect. Stimulated DETC secrete cytokines, e.g. the pro-inflammatory cytokine interferon-gamma (IFNγ), and thereby regulate skin homeostasis. Addition of butyrate and propionate to the cultures at non-toxic concentrations decreased secretion of IFNγ by DETC and increased the expression of the immunoregulatory surface receptor CD69. We hypothesize that SCFA can dampen the inflammatory activity of DETC.
Project description:Environmental factors driving the development of type 1 diabetes (T1D) are still largely unknown. Both animal and human studies have shown an association between altered fecal microbiota composition, impaired production of short-chain fatty acids (SCFA) and T1D onset. However, observational evidence on SCFA and fecal and oral microbiota in adults with longstanding T1D vs healthy controls (HC) is lacking.We included 53 T1D patients without complications or medication and 50 HC matched for age, sex and BMI. Oral and fecal microbiota, fecal and plasma SCFA levels, markers of intestinal inflammation (fecal IgA and calprotectin) and markers of low-grade systemic inflammation were measured.Oral microbiota were markedly different in T1D (eg abundance of Streptococci) compared to HC. Fecal analysis showed decreased butyrate producing species in T1D and less butyryl-CoA transferase genes. Also, plasma levels of acetate and propionate were lower in T1D, with similar fecal SCFA. Finally, fecal strains Christensenella and Subdoligranulum correlated with glycemic control, inflammatory parameters and SCFA.We conclude that T1D patients harbor a different amount of intestinal SCFA (butyrate) producers and different plasma acetate and propionate levels. Future research should disentangle cause and effect and whether supplementation of SCFA-producing bacteria or SCFA alone can have disease-modifying effects in T1D.
Project description:Short-chain fatty acids (SCFAs) are produced by microbial fermentation of dietary fiber in the gut. Butyrate is a particularly important SCFA with anti-inflammatory properties and is generally present at lower levels in inflammatory diseases associated with gut microbiota dysbiosis in mammals. We aimed to determine if SCFAs are produced by the zebrafish microbiome and if SCFAs exert conserved effects on zebrafish immunity as an example of the non-mammalian vertebrate immune system. We demonstrate that bacterial communities from adult zebrafish intestines synthesize all three main SCFA <i>in vitro</i>, although SCFA were below our detectable limits in zebrafish intestines <i>in vivo</i>. Immersion in butyrate, but not acetate or propionate, reduced the recruitment of neutrophils and M1-type pro-inflammatory macrophages to wounds. We found conservation of butyrate sensing by neutrophils via orthologs of the <i>hydroxycarboxylic acid receptor 1</i> (<i>hcar1</i>) gene. Neutrophils from Hcar1-depleted embryos were no longer responsive to the anti-inflammatory effects of butyrate, while macrophage sensitivity to butyrate was independent of Hcar1. Our data demonstrate conservation of anti-inflammatory butyrate effects and identify the presence of a conserved molecular receptor in fish.
Project description:Background: Acetate, propionate, and butyrate are the main short-chain fatty acids (SCFA) produced in the colon as a result of microbial fermentation of dietary fibers. An increasing amount of evidence suggests that these SCFA have major health benefits. The composition of the microbiota is altered by dietary fat, and this is believed to impact SCFA production. Currently it is unknown whether host gene expression responses to SCFA are modulated by fat content of the diet. The aim of this study was to compare the changes in colonic gene expression profiles after acetate, propionate and butyrate infusions between a low fat and high fat diet. Methods: Male C57BL/6J mice were fed semi-synthetic low fat (10 energy%) or high fat (45 E%) diets starting 2 weeks before the SCFA treatment period. During treatment, mice received a rectal infusion of either an acetate, propionate, butyrate, or a saline (control) solution for 6 consecutive days, after which colon was subjected to gene expression profiling. Unsupervised visualization of the dataset was performed using Independent Principal Component Analysis. For each SCFA, similarities of its effects on a low fat and a high fat diet were assessed using Rank-Rank Hypergeometric Overlap. In addition, differentially expressed genes were identified, and gene set enrichment analysis was performed to determine functional implications of the regulated genes. Results: Taking into account the complete dataset, we observed that more variation in gene expression profiles was explained by fat content of the diet than by SCFA treatment. Gene expression responses to acetate and butyrate were similar on the low fat versus high fat diet, but were opposite for propionate. Functionally the expression changes reflected differential modulation of several metabolic processes; genes involved in oxidative phosphorylation, lipid catabolism, lipoprotein metabolism and cholesterol transport were suppressed by acetate and butyrate treatment, whereas propionate treatment resulted in changes in fatty acid and sterol biosynthesis, and in amino acid and carbohydrate metabolism. Conclusions: We demonstrated that dietary fat content impacts the colonic gene expression response to propionate, and to a lesser extent to acetate and butyrate. The study demonstrates that knowledge on diet composition is essential when studying effects of SCFAs on metabolism.