We examined the effects of gut microbial catabolites of tryptophan on the aryl hydrocarbon receptor (AhR). Using a reporter gene assay, we show that all studied catabolites are low-potency agonists of human AhR. The efficacy of catabolites differed substantially, comprising agonists with no or low (i3-propionate, i3-acetate, i3-lactate, i3-aldehyde), medium (i3-ethanol, i3-acrylate, skatole, tryptamine), and high (indole, i3-acetamide, i3-pyruvate) efficacies. We displayed ligand-selective antagonist activities by i3-pyruvate, i3-aldehyde, indole, skatole, and tryptamine. Ligand binding assay identified low affinity (skatole, i3-pyruvate, and i3-acetamide) and very low affinity (i3-acrylate, i3-ethanol, indole) ligands of the murine AhR. Indole, skatole, tryptamine, i3-pyruvate, i3-acrylate, and i3-acetamide induced CYP1A1 mRNA in intestinal LS180 and HT-29 cells, but not in the AhR-knockout HT-29 variant. We observed a similar CYP1A1 induction pattern in primary human hepatocytes. The most AhR-active catabolites (indole, skatole, tryptamine, i3-pyruvate, i3-acrylate, i3-acetamide) elicited nuclear translocation of the AhR, followed by a formation of AhR-ARNT heterodimer and enhanced binding of the AhR to the CYP1A1 gene promoter. Collectively, we comprehensively characterized the interactions of gut microbial tryptophan catabolites with the AhR, which may expand the current understanding of their potential roles in intestinal health and disease.

• MeSH
• cytochrom P-450 CYP1A1 genetika   MeSH
• exprese genu MeSH
• indoly MeSH
• lidé MeSH
• ligandy MeSH
• metabolické sítě a dráhy MeSH
• multimerizace proteinu MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• promotorové oblasti (genetika) MeSH
• receptory aromatických uhlovodíků agonisté   metabolismus   MeSH
• reportérové geny MeSH
• střevní mikroflóra * účinky léků   MeSH
• transkripční faktory bHLH agonisté   metabolismus   MeSH
• tryptofan metabolismus   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Expansions of trinucleotide repeats (TNRs) are associated with genetic disorders such as Friedreich's ataxia. The tumor suppressor p53 is a central regulator of cell fate in response to different types of insults. Sequence and structure-selective modes of DNA recognition are among the main attributes of p53 protein. The focus of this work was analysis of the p53 structure-selective recognition of TNRs associated with human neurodegenerative diseases. Here, we studied binding of full length p53 and several deletion variants to TNRs folded into DNA hairpins or loops. We demonstrate that p53 binds to all studied non-B DNA structures, with a preference for non-B DNA structures formed by pyrimidine (Py) rich strands. Using deletion mutants, we determined the C-terminal DNA binding domain of p53 to be crucial for recognition of such non-B DNA structures. We also observed that p53 in vitro prefers binding to the Py-rich strand over the purine (Pu) rich strand in non-B DNA substrates formed by sequence derived from the first intron of the frataxin gene. The binding of p53 to this region was confirmed using chromatin immunoprecipitation in human Friedreich's ataxia fibroblast and adenocarcinoma cells. Altogether these observations provide further evidence that p53 binds to TNRs' non-B DNA structures.

• MeSH
• DNA chemie   metabolismus   MeSH
• expanze trinukleotidových repetic * MeSH
• exprese genu MeSH
• Friedreichova ataxie genetika   metabolismus   MeSH
• interakční proteinové domény a motivy MeSH
• konformace nukleové kyseliny * MeSH
• lidé MeSH
• nádorový supresorový protein p53 chemie   metabolismus   MeSH
• pyrimidiny MeSH
• rekombinantní proteiny MeSH
• trinukleotidové repetice * MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH