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.

• Klíčová slova
• AhR, CYP1A1, FICZ, HDAC, Microbiota, SCFAs, butyrate, metabolites, tryptophan,
• 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
• Názvy látek
• butyráty MeSH
• ligandy MeSH
• receptory aromatických uhlovodíků * MeSH
• tryptofan MeSH

Employing methods of cell biology and proteome analysis tools, we examined effects of an inhibitor of histone deacetylases, sodium butyrate (SB), on the proliferation/differentiation characteristics of chronic myelogenous leukemia (CML)-derived cells K562. SB suppressed proliferation of K562 cells by inducing cell cycle arrest in G1 phase, which was followed by their transition to G0 phase (decrease of Ki-67 antigen-positive cells) and erythroid differentiation (increased glycophorin A expression and synthesis of hemoglobins). Neither terminal apoptosis (low counts of TUNEL-positive cells) nor necrosis (moderate counts of propidium iodide-positive cells) occurred. Importantly, SB attenuated protein expression of CML-related chimeric kinase BCR-ABL that is responsible for the deregulated proliferation of CML cells. The proteomic analysis (2-D electrophoresis combined with MALDI-TOF mass spectrometry and/or Western blotting) revealed several proteins that were differentially expressed or their mobility was altered due to butyrate treatment, namely, HSP90, HSP70, p23, cyclophilin A (CYPA), prefoldin2 (PFD2) and alpha-, gamma-, epsilon-human globin chains. Perturbation of HSP90 multichaperone complex of which BCR-ABL is the client protein is presumably a cause of BCR-ABL suppression. Changes in other proteins with chaperonic functions, CYPA and PFD2, may reflect SB antiproliferative and cytodifferentiation effects.

• MeSH
• buněčná diferenciace účinky léků   MeSH
• buňky K562 MeSH
• butyráty farmakologie   MeSH
• G1 fáze účinky léků   MeSH
• lidé MeSH
• proliferace buněk účinky léků   MeSH
• proteom biosyntéza   MeSH
• proteomika * MeSH
• regulace genové exprese u leukemie účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• butyráty MeSH
• proteom MeSH

Labelled sodium isobutyrate [(CD3)2-CHCOONa] was added to the culture medium of Streptomyces fradiae and up to 14 atoms of deuterium were found to be incorporated into a molecule of tylosin aglycone (tylactone). This observation is in accordance with the data in the literature. When fatty acids were analyzed, as much as 34% of the isobutyrate incorporated into the cell was formed to be transformed into butyrate that was used for the synthesis of even, straight-chain fatty acids; 57% of the labelled isobutyrate was incorporated into the even isoacids, whereas 9% was degraded to propionate and further used for the synthesis of the odd acids.

• MeSH
• butyráty metabolismus   MeSH
• hmotnostní spektrometrie MeSH
• isobutyráty MeSH
• kyselina máselná MeSH
• mastné kyseliny biosyntéza   MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
• Streptomyces metabolismus   MeSH
• tylosin biosyntéza   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• butyráty MeSH
• isobutyráty MeSH
• isobutyric acid MeSH Prohlížeč
• kyselina máselná MeSH
• mastné kyseliny MeSH
• tylosin MeSH

The acquisition of the infant gut microbiota is key to establishing a host-microbiota symbiosis. Microbially produced metabolites tightly interact with the immune system, and the fermentation-derived short-chain fatty acid butyrate is considered an important mediator linked to chronic diseases later in life. The intestinal butyrate-forming bacterial population is taxonomically and functionally diverse and includes endospore formers with high transmission potential. Succession, and contribution of butyrate-producing taxa during infant gut microbiota development have been little investigated. We determined the abundance of major butyrate-forming groups and fermentation metabolites in faeces, isolated, cultivated and characterized the heat-resistant cell population, which included endospores, and compared butyrate formation efficiency of representative taxa in batch cultures. The endospore community contributed about 0.001% to total cells, and was mainly composed of the pioneer butyrate-producing Clostridium sensu stricto. We observed an increase in abundance of Faecalibacterium prausnitzii, butyrate-producing Lachnospiraceae and faecal butyrate levels with age that is likely explained by higher butyrate production capacity of contributing taxa compared with Clostridium sensu stricto. Our data suggest that a successional arrangement and an overall increase in abundance of butyrate forming populations occur during the first year of life, which is associated with an increase of intestinal butyrate formation capacity.

• MeSH
• Bacteria klasifikace   genetika   izolace a purifikace   metabolismus   MeSH
• butyráty metabolismus   MeSH
• feces chemie   mikrobiologie   MeSH
• fermentace MeSH
• kojenec MeSH
• kyseliny mastné těkavé metabolismus   MeSH
• lidé MeSH
• spory bakteriální klasifikace   genetika   izolace a purifikace   metabolismus   MeSH
• střeva růst a vývoj   mikrobiologie   MeSH
• střevní mikroflóra fyziologie   MeSH
• Check Tag
• kojenec MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• butyráty MeSH
• kyseliny mastné těkavé MeSH

Butyrate and isobutyrate (after isomerization to n-butyrate) are specific precursors for the biosynthesis of monensin A in Streptomyces cinnamonensis. High concentrations of both butyrate and isobutyrate (greater than 20 and 10 mM, respectively) were toxic to S. cinnamonensis plated on solid medium. Spontaneous mutants resistant to these substances were isolated. These new strains produced monensins at even higher concentrations of butyrate or isobutyrate, with an increased yield of monensin A. S. cinnamonensis produced an anti-isobutyrate (AIB) factor, which was originally found to be excreted by some isobutyrate-resistant stains growing on solid medium containing isobutyrate. On plates, the AIB factor efficiently counteracted toxic concentrations not only of isobutyrate, but also of acetate, propionate, butyrate, 2-methylbutyrate, valerate and isovalerate against S. cinnamonensis as well as other Streptomyces species. Although the AIB factor enabled normal growth, sporulation and monensin production on plates, it did not have positive effects on submerged cultures of S. cinnamonensis with isobutyrate. The partial purification of the AIB factor was achieved. The role of the AIB factor during spore germination on solid medium containing isobutyrate or its homologues is discussed.

• MeSH
• antibiotická rezistence genetika   MeSH
• biologické faktory analýza   metabolismus   MeSH
• butyráty antagonisté a inhibitory   farmakologie   MeSH
• isobutyráty MeSH
• kyselina máselná MeSH
• monensin biosyntéza   MeSH
• mutace MeSH
• Streptomyces účinky léků   genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biologické faktory MeSH
• butyráty MeSH
• isobutyráty MeSH
• isobutyric acid MeSH Prohlížeč
• kyselina máselná MeSH
• monensin MeSH

The high level of alkaline phosphatase activity in HT29 cells induced after 2 or 5 days of butyrate treatment was decreased during their prolonged exposure (about 30 days) to this agent together with a decrease of sensitivity to apoptosis. However, an enormous additive effect on alkaline phosphatase activity was found after butyrate treatment of glucose-starved cells. In concert with this finding, the substructural analysis revealed a dense brush border, tendency to polarization and morphologically normal mitochondria. It can be concluded that prolonged butyrate treatment of HT29 cells attenuated their response to this agent. On the other hand, glucose deprivation, as another inductor of differentiation, was found to increase the sensitivity of HT29 cells to butyrate.

• MeSH
• buněčná diferenciace fyziologie   MeSH
• buňky HT-29 metabolismus   ultrastruktura   MeSH
• butyráty metabolismus   MeSH
• elektronová mikroskopie MeSH
• glukosa metabolismus   MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• butyráty MeSH
• glukosa MeSH

Experimental and epidemiological evidence supports the idea that dietary fat and fiber influence colon carcinogenesis. Particularly, their components, n-3 polyunsaturated fatty acids (PUFAs) and butyrate, have been proven to exhibit beneficial effects on colon epithelial cell metabolism, signaling, and kinetics, thus preventing colon inflammation and cancer. Moreover, these effects may be strengthened by PUFA and butyrate combination. It appears that administration of these compounds might be a relatively nontoxic form of supportive therapy improving cancer treatment outcomes and slowing down or preventing recurrence of certain types of cancer. However, their efficient application has to be based on solid scientific evidence of their mechanisms of action from the molecular and cellular to the organismal level. In this review, we emphasize the role of lipids and their metabolism during tumor development, describe some important mechanisms considering cellular and molecular levels of PUFA and butyrate action in colon epithelial cells, and particularly focus on the interaction of their metabolism and the signaling pathways with respect to the differences in response of normal and cancer colon cells.

• MeSH
• butyráty metabolismus   MeSH
• lidé MeSH
• metabolismus lipidů MeSH
• nádory tračníku metabolismus   MeSH
• nenasycené mastné kyseliny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• butyráty MeSH
• nenasycené mastné kyseliny 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.

• Klíčová slova
• butyrate, ceramides, colon cancer, docosahexaenoic acid, lipid analyses, phospholipids,
• 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
• Názvy látek
• butyráty MeSH
• kyseliny dokosahexaenové MeSH
• membránové lipidy 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.

• Klíčová slova
• Butyrate, Colon epithelium, N-acetyltransferases, NAD(P)H:quinone oxidoreductase 1, Polycyclic aromatic hydrocarbons, UDP-glucuronosyltransferases,
• 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
• Názvy látek
• benzopyren MeSH
• butyráty MeSH
• karcinogeny MeSH
• oxidoreduktasy MeSH
• transferasy MeSH
• xenobiotika 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.

• Klíčová slova
• Aryl hydrocarbon receptor, Butyrate, Cytochromes P450, Drug metabolism, gut-liver axis,
• MeSH
• butyráty * metabolismus   farmakologie   MeSH
• játra metabolismus   MeSH
• kolon metabolismus   MeSH
• kyseliny mastné těkavé metabolismus   MeSH
• lidé MeSH
• receptory aromatických uhlovodíků genetika   metabolismus   MeSH
• střevní mikroflóra * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• butyráty * MeSH
• kyseliny mastné těkavé MeSH
• receptory aromatických uhlovodíků MeSH