Aryl hydrocarbon receptor (AhR) is a critical player in the crosstalk between the gut microbiota and its host. However, factors regulating AhR within the gut, which is a complex metabolomic environment, are poorly understood. This study investigates the effect of a combination of metabolites on the activation mechanism of AhR. AhR activity was evaluated using both a luciferase reporter system and mRNA levels of AhR target genes on human cell lines and human colonic explants. AhR activation was studied by radioligand-binding assay, nuclear translocation of AhR by immuofluorescence and protein co-immunoprecipitation of AhR with ARNT. Indirect activation of AhR was evaluated using several tests and inhibitors. The promoter of the target gene CYP1A1 was studied both by chromatin immunoprecipitation and by using an histone deacetylase HDAC inhibitor (iHDAC). Short-chain fatty acids, and butyrate in particular, enhance AhR activity mediated by endogenous tryptophan metabolites without binding to the receptor. This effect was confirmed in human intestinal explants and did not rely on activation of receptors targeted by SCFAs, inhibition of AhR degradation or clearance of its ligands. Butyrate acted directly on AhR target gene promoter to reshape chromatin through iHDAC activity. Our findings revealed that butyrate is not an AhR ligand but acts as iHDAC leading to an increase recruitment of AhR to the target gene promoter in the presence of tryptophan-derived AhR agonists. These data contribute to a novel understanding of the complex regulation of AhR activation by gut microbiota-derived metabolites.
- MeSH
- butyráty farmakologie MeSH
- lidé MeSH
- ligandy MeSH
- receptory aromatických uhlovodíků * genetika metabolismus MeSH
- střevní mikroflóra * MeSH
- tryptofan MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Several studies have indicated the beneficial anti-inflammatory effect of butyrate in inflammatory bowel disease (IBD) therapy implying attempts to increase butyrate production in the gut through orally administered dietary supplementation. Through the gut-liver axis, however, butyrate may reach directly the liver and influence the drug-metabolizing ability of hepatic enzymes, and, indirectly, also the outcome of applied pharmacotherapy. The focus of our study was on the liver microsomal cytochrome P450 (CYP) 2A5, which is a mouse orthologue of human CYP2A6 responsible for metabolism of metronidazole, an antibiotic used to treat IBD. Our findings revealed that specific pathogen-free (SPF) and germ-free (GF) mice with dextran sulfate sodium (DSS)-induced colitis varied markedly in enzyme activity of CYP2A and responded differently to butyrate pre-treatment. A significant decrease (to 50%) of the CYP2A activity was observed in SPF mice with colitis; however, an administration of butyrate prior to DSS reversed this inhibition effect. This phenomenon was not observed in GF mice. The results highlight an important role of gut microbiota in the regulation of CYP2A under inflammatory conditions. Due to the role of CYP2A in metronidazole metabolism, this phenomenon may have an impact on the IBD therapy. Butyrate administration, hence, brings promising therapeutic potential for improving symptoms of gut inflammation; however, possible interactions with drug metabolism need to be further studied.
- MeSH
- antibakteriální látky škodlivé účinky farmakologie terapeutické užití MeSH
- antiflogistika farmakologie MeSH
- butyráty * farmakologie MeSH
- metronidazol farmakologie MeSH
- modely nemocí na zvířatech MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- síran dextranu škodlivé účinky MeSH
- střevní mikroflóra * MeSH
- systém (enzymů) cytochromů P-450 metabolismus MeSH
- ulcerózní kolitida * chemicky indukované farmakoterapie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Modulation of gut microbiome composition seems to be a promising therapeutic strategy for a wide range of pathologic states. However, these microbiota-targeted interventions may affect production of microbial metabolites, circulating factors in the gut-liver axis influencing hepatic drug metabolism with possible clinical relevance. Butyrate, a short-chain fatty acid produced through microbial fermentation of dietary fibers in the colon, has well established anti-inflammatory role in the intestine, while the effect of butyrate on the liver is unknown. In this study, we have evaluated the effect of butyrate on hepatic AhR activity and AhR-regulated gene expression. We have showed that AhR and its target genes were upregulated by butyrate in dose-dependent manner in HepG2-C3 as well as in primary human hepatocytes. The involvement of AhR has been proved using specific AhR antagonists and siRNA-mediated AhR silencing. Experiments with AhR reporter cells have shown that butyrate regulates the expression of AhR target genes by modulating the AhR activity. Our results suggest also epigenetic action by butyrate on AhR and its repressor (AHRR) presumably through mechanisms based on HDAC inhibition in the liver. Our results demonstrate that butyrate may influence the drug-metabolizing ability of liver enzymes e.g., through the interaction with AhR-dependent pathways.
Postbiotics are health-promoting microbial metabolites delivered as a functional food or a food supplement. They either directly influence signaling pathways of the body or indirectly manipulate metabolism and the composition of intestinal microflora. Cancer is the second leading cause of death worldwide and even though the prognosis of patients is improving, it is still poor in the substantial part of the cases. The preventable nature of cancer and the importance of a complex multi-level approach in anticancer therapy motivate the search for novel avenues of establishing the anticancer environment in the human body. This review summarizes the principal findings demonstrating the usefulness of both natural and synthetic sources of postbotics in the prevention and therapy of cancer. Specifically, the effects of crude cell-free supernatants, the short-chain fatty acid butyrate, lactic acid, hydrogen sulfide, and β-glucans are described. Contradictory roles of postbiotics in healthy and tumor tissues are highlighted. In conclusion, the application of postbiotics is an efficient complementary strategy to combat cancer.
- MeSH
- beta-glukany farmakologie MeSH
- butyráty farmakologie MeSH
- kyselina mléčná farmakologie MeSH
- kyseliny mastné těkavé metabolismus farmakologie MeSH
- lidé MeSH
- metabolom MeSH
- nádory dietoterapie metabolismus MeSH
- potravní doplňky mikrobiologie MeSH
- prebiotika mikrobiologie MeSH
- probiotika metabolismus farmakologie MeSH
- střevní mikroflóra účinky léků MeSH
- sulfan farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Butyrate helps to maintain colon homeostasis and exhibits chemopreventive effects in colon epithelium. We examined the interactive effects of butyrate and benzo[a]pyrene (BaP), dietary carcinogen, in regulation of expression of a panel of phase I and II xenobiotic metabolizing enzymes (XMEs) in human colon cells. In human colon carcinoma HCT-116 and HT-29 cell lines, butyrate alone increased mRNA levels of some enzymes, such as N-acetyltransferases (in particular NAT2). In combination with BaP, butyrate potentiated induction of cytochrome P450 family 1 enzymes (CYP1A1), aldo-keto reductases (AKR1C1) or UDP-glucuronosyltransferases (UGT1A1). There were some notable differences between cell lines, as butyrate potentiated induction of NAD(P)H:quinone oxidoreductase 1 (NQO1) and UGT1A4 only in HCT-116 cells, and it even repressed AKR1C3 induction in HT-29 cells. Butyrate also promoted induction of CYP1, NQO1, NAT2, UGT1A1 or UGT1A4 in human colon Caco-2 cells, in a differentiation-dependent manner. Differentiated Caco-2 cells exhibited a higher inducibility of selected XME genes than undifferentiated cells. Butyrate increased induction of enzymatic activities of NATs, NQO1 and UGTs by BaP in HCT-116 and HT29 cells, whereas in differentiated Caco-2 cells it helped to increase only enzymatic activity of NQO1 and UGTs. Together, the present data suggest that butyrate may modulate expression/activities of several enzymes involved in metabolism of carcinogens in colon. In some cases (NAT2, UGT1 A1), this was linked to inhibition of histone deacetylases (HDAC), as confirmed by using HDAC inhibitor trichostatin A. These results may have implications for our understanding of the role of butyrate in regulation of XMEs and carcinogen metabolism in colon.
- MeSH
- benzopyren toxicita MeSH
- buněčné linie MeSH
- butyráty farmakologie MeSH
- epitelové buňky účinky léků metabolismus MeSH
- karcinogeny toxicita MeSH
- kolon cytologie MeSH
- lidé MeSH
- oxidoreduktasy genetika metabolismus MeSH
- transferasy genetika metabolismus MeSH
- xenobiotika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Butyrate produced by the intestinal microbiota is essential for proper functioning of the intestinal immune system. Total dependence on parenteral nutrition (PN) is associated with numerous adverse effects, including severe microbial dysbiosis and loss of important butyrate producers. We hypothesised that a lack of butyrate produced by the gut microbiota may be compensated by its supplementation in PN mixtures. We tested whether i.v. butyrate administration would (a) positively modulate intestinal defence mechanisms and (b) counteract PN-induced dysbiosis. Male Wistar rats were randomised to chow, PN, and PN supplemented with 9 mM butyrate (PN+But) for 12 days. Antimicrobial peptides, mucins, tight junction proteins, and cytokine expression were assessed by RT-qPCR. T-cell subpopulations in mesenteric lymph nodes (MLN) were analysed by flow cytometry. Microbiota composition was assessed in caecum content. Butyrate supplementation resulted in increased expression of tight junction proteins (ZO-1, claudin-7, E-cadherin), antimicrobial peptides (Defa 8, Rd5, RegIIIγ), and lysozyme in the ileal mucosa. Butyrate partially alleviated PN-induced intestinal barrier impairment and normalised IL-4, IL-10, and IgA mRNA expression. PN administration was associated with an increase in Tregs in MLN, which was normalised by butyrate. Butyrate increased the total number of CD4+ and decreased a relative amount of CD8+ memory T cells in MLN. Lack of enteral nutrition and PN administration led to a shift in caecal microbiota composition. Butyrate did not reverse the altered expression of most taxa but did influence the abundance of some potentially beneficial/pathogenic genera, which might contribute to its overall beneficial effect.
- MeSH
- biodiverzita MeSH
- butyráty farmakologie MeSH
- fenotyp MeSH
- fylogeneze MeSH
- ileum účinky léků patologie MeSH
- kolon účinky léků patologie MeSH
- lymfatické uzliny účinky léků metabolismus MeSH
- lymfocyty účinky léků metabolismus MeSH
- messenger RNA genetika metabolismus MeSH
- modely u zvířat MeSH
- muciny biosyntéza MeSH
- Panethovy buňky účinky léků metabolismus MeSH
- parenterální výživa * MeSH
- peptidy genetika metabolismus MeSH
- permeabilita MeSH
- potkani Wistar MeSH
- potravní doplňky * MeSH
- proteiny těsného spoje metabolismus MeSH
- regulace genové exprese účinky léků MeSH
- střeva patologie MeSH
- střevní mikroflóra * účinky léků MeSH
- tenké střevo účinky léků MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- Apiaceae chemie MeSH
- butyráty chemie farmakologie MeSH
- cytokiny imunologie MeSH
- furany chemie farmakologie MeSH
- kultivované buňky MeSH
- lidé MeSH
- molekulární struktura MeSH
- myši MeSH
- oxid dusnatý imunologie MeSH
- peritoneum cytologie MeSH
- potkani Wistar MeSH
- semena rostlinná chemie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Docosahexaenoic acid (DHA) and sodium butyrate (NaBt) exhibit a number of interactive effects on colon cancer cell growth, differentiation, or apoptosis; however, the molecular mechanisms responsible for these interactions and their impact on cellular lipidome are still not fully clear. Here, we show that both dietary agents together induce dynamic alterations of lipid metabolism, specific cellular lipid classes, and fatty acid composition. In HT-29 cell line, a model of differentiating colon carcinoma cells, NaBt supported incorporation of free DHA into non-polar lipids and their accumulation in cytoplasmic lipid droplets. DHA itself was not incorporated into sphingolipids; however, it significantly altered representation of individual ceramide (Cer) classes, in particular in combination with NaBt (DHA/NaBt). We observed altered expression of enzymes involved in Cer metabolism in cells treated with NaBt or DHA/NaBt, and exogenous Cer 16:0 was found to promote induction of apoptosis in differentiating HT-29 cells. NaBt, together with DHA, increased n-3 fatty acid synthesis and attenuated metabolism of monounsaturated fatty acids. Finally, DHA and/or NaBt altered expression of proteins involved in synthesis of fatty acids, including elongase 5, stearoyl CoA desaturase 1, or fatty acid synthase, with NaBt increasing expression of caveolin-1 and CD36 transporter, which may further promote DHA incorporation and its impact on cellular lipidome. In conclusion, our results indicate that interactions of DHA and NaBt exert complex changes in cellular lipidome, which may contribute to the alterations of colon cancer cell differentiation/apoptotic responses. The present data extend our knowledge about the nature of interactive effects of dietary fatty acids.
- MeSH
- apoptóza účinky léků MeSH
- buněčná diferenciace účinky léků MeSH
- butyráty farmakologie MeSH
- HCT116 buňky MeSH
- kyseliny dokosahexaenové farmakologie MeSH
- lidé MeSH
- membránové lipidy klasifikace metabolismus MeSH
- metabolismus lipidů účinky léků MeSH
- nádory tračníku metabolismus patologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The short-chain and n-3 polyunsaturated fatty acids exhibit anticancer properties, and they may mutually interact within the colon. However, the molecular mechanisms of their action in colon cancer cells are still not fully understood. Our study focused on the mechanisms responsible for the diverse effects of sodium butyrate (NaBt), in particular when interacting with docosahexaenoic acid (DHA), in distinct colon cancer cell types, in which NaBt either induces cell differentiation or activates programmed cell death involving mitochondrial pathway. NaBt activated autophagy both in HT-29 cells, which are sensitive to induction of differentiation, and in nondifferentiating HCT-116 cells. However, autophagy supported cell survival only in HT-29 cells. Combination of NaBt with DHA-promoted cell death, especially in HCT-116 cells and after longer time intervals. The inhibition of autophagy both attenuated differentiation and enhanced apoptosis in HT-29 cells treated with NaBt and DHA, but it had no effect in HCT-116 cells. NaBt, especially in combination with DHA, activated PPARγ in both cell types. PPARγ silencing decreased differentiation and increased apoptosis only in HT-29 cells, therefore we verified the role of caspases in apoptosis, differentiation and also PPARγ activity using a pan-caspase inhibitor. In summary, our data suggest that diverse responses of colon cancer cells to fatty acids may rely on their sensitivity to differentiation, which may in turn depend on distinct engagement of autophagy, caspases and PPARγ. These results contribute to understanding of mechanisms underlying differential effects of NaBt, when interacting with other dietary fatty acids, in colon cancer cells.
- MeSH
- antitumorózní látky farmakologie MeSH
- apoptóza účinky léků MeSH
- autofagie účinky léků MeSH
- buněčná diferenciace účinky léků MeSH
- buňky HT-29 MeSH
- butyráty farmakologie MeSH
- HCT116 buňky MeSH
- kaspasa 3 genetika metabolismus MeSH
- kyselina máselná farmakologie MeSH
- kyseliny dokosahexaenové farmakologie MeSH
- lidé MeSH
- mitochondrie účinky léků metabolismus MeSH
- nádory tračníku patologie MeSH
- PPAR gama genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
