The human microbiota is a complex ecosystem that colonizes body surfaces and interacts with host organ systems, especially the immune system. Since the composition of this ecosystem depends on a variety of internal and external factors, each individual harbors a unique set of microbes. These differences in microbiota composition make individuals either more or less susceptible to various diseases, including cancer. Specific microbes are associated with cancer etiology and pathogenesis and several mechanisms of how they drive the typical hallmarks of cancer were recently identified. Although most microbes reside in the distal gut, they can influence cancer initiation and progression in distant tissues, as well as modulate the outcomes of established cancer therapies. Here, we describe the mechanisms by which microbes influence carcinogenesis and discuss their current and potential future applications in cancer diagnostics and management.

• Klíčová slova
• Fecal microbiota transplantation, Gut microbiota, Hallmarks of cancer, Tumor microenvironment,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The present study investigated whether neonatal exposure to the proinflammatory endotoxin lipopolysaccharide (LPS) followed by an antibiotic (ATB)-induced dysbiosis in early adulthood could induce neurodevelopmental disorders-like behavioral changes in adult male rats. Combining these two stressors resulted in decreased weight gain, but no significant behavioral abnormalities were observed. LPS treatment resulted in adult rats' hypoactivity and induced anxiety-like behavior in the social recognition paradigm, but these behavioral changes were not exacerbated by ATB-induced gut dysbiosis. ATB treatment seriously disrupted the gut bacterial community, but dysbiosis did not affect locomotor activity, social recognition, and acoustic reactivity in adult rats. Fecal bacterial community analyses showed no differences between the LPS challenge exposed/unexposed rats, while the effect of ATB administration was decisive regardless of prior LPS exposure. ATB treatment resulted in significantly decreased bacterial diversity, suppression of Clostridiales and Bacteroidales, and increases in Lactobacillales, Enterobacteriales, and Burkholderiales. The persistent effect of LPS on some aspects of behavior suggests a long-term effect of early toxin exposure that was not observed in ATB-treated animals. However, an anti-inflammatory protective effect of ATB cannot be assumed because of the increased abundance of pro-inflammatory, potentially pathogenic bacteria (Proteus, Suttrella) and the elimination of the bacterial families Ruminococcaceae and Lachnospiraceae, which are generally considered beneficial for gut health.

• Klíčová slova
• Antibiotics, Behavior, Lipopolysaccharide, Microbiome, Rats,
• Publikační typ
• časopisecké články MeSH

Xenobiotic receptors, such as the pregnane X receptor, regulate multiple host physiologic pathways including xenobiotic metabolism, certain aspects of cellular metabolism, and innate immunity. These ligand-dependent nuclear factors regulate gene expression via genomic recognition of specific promoters and transcriptional activation of the gene. Natural or endogenous ligands are not commonly associated with this class of receptors; however, since these receptors are expressed in a cell-type specific manner in the liver and intestines, there has been significant recent effort to characterize microbially derived metabolites as ligands for these receptors. In general, these metabolites are thought to be weak micromolar affinity ligands. This journal anniversary minireview focuses on recent efforts to derive potentially nontoxic microbial metabolite chemical mimics that could one day be developed as drugs combating xenobiotic receptor-modifying pathophysiology. The review will include our perspective on the field and recommend certain directions for future research. SIGNIFICANCE STATEMENT: Xenobiotic receptors (XRs) regulate host drug metabolism, cellular metabolism, and immunity. Their presence in host intestines allows them to function not only as xenosensors but also as a response to the complex metabolic environment present in the intestines. Specifically, this review focuses on describing microbial metabolite-XR interactions and the translation of these findings toward discovery of novel chemical mimics as potential drugs of the future for diseases such as inflammatory bowel disease.

• MeSH
• ligandy MeSH
• steroidní receptory * metabolismus   MeSH
• střeva MeSH
• transportní proteiny MeSH
• xenobiotika metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• ligandy MeSH
• steroidní receptory * MeSH
• transportní proteiny MeSH
• xenobiotika MeSH

Aryl hydrocarbon receptor (AHR) plays pivotal roles in intestinal physiology and pathophysiology. Intestinal AHR is activated by numerous dietary, endogenous, and microbial ligands. Whereas the effects of individual compounds on AHR are mostly known, the effects of real physiological mixtures occurring in the intestine have not been studied. Using reporter gene assays and RT-PCR, we evaluated the combinatorial effects (3520 combinations) of 11 microbial catabolites of tryptophan (MICTs) on AHR. We robustly (n = 30) determined the potencies and relative efficacies of single MICTs. Synergistic effects of MICT binary mixtures were observed between low- or medium-efficacy agonists, in particular for combinations of indole-3-propionate and indole-3-lactate. Combinations comprising highly efficacious agonists such as indole-3-pyruvate displayed rather antagonist effects, caused by saturation of the assay response. These synergistic effects were confirmed by RT-PCR as CYP1A1 mRNA expression. We also tested mimic multicomponent and binary mixtures of MICTs, prepared based on the metabolomic analyses of human feces and colonoscopy aspirates, respectively. In this case, AHR responsiveness did not correlate with type of diet or health status, and the indole concentrations in the mixtures were determinative of gross AHR activity. Future systematic research on the synergistic activation of AHR by microbial metabolites and other ligands is needed.

• Klíčová slova
• aryl hydrocarbon receptor, indole derivatives, microbiome, mimic mixtures, tryptophan metabolites,
• MeSH
• cytochrom P-450 CYP1A1 genetika   metabolismus   MeSH
• indoly metabolismus   farmakologie   MeSH
• lidé MeSH
• ligandy MeSH
• messenger RNA metabolismus   MeSH
• propionáty MeSH
• pyruváty MeSH
• receptory aromatických uhlovodíků * metabolismus   MeSH
• střeva MeSH
• tryptofan * metabolismus   farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cytochrom P-450 CYP1A1 MeSH
• indoly MeSH
• ligandy MeSH
• messenger RNA MeSH
• propionáty MeSH
• pyruváty MeSH
• receptory aromatických uhlovodíků * MeSH
• tryptofan * MeSH

Gastrointestinal microbes respond to biochemical metabolites that coordinate their behaviors. Here, we demonstrate that bacterial indole functions as a multifactorial mitigator of Klebsiella grimontii and Klebsiella oxytoca pathogenicity. These closely related microbes produce the enterotoxins tilimycin and tilivalline; cytotoxin-producing strains are the causative agent of antibiotic-associated hemorrhagic colitis and have been associated with necrotizing enterocolitis of premature infants. We demonstrate that carbohydrates induce cytotoxin synthesis while concurrently repressing indole biosynthesis. Conversely, indole represses cytotoxin production. In both cases, the alterations stemmed from differential transcription of npsA and npsB, key genes involved in tilimycin biosynthesis. Indole also enhances conversion of tilimycin to tilivalline, an indole analog with reduced cytotoxicity. In this context, we established that tilivalline, but not tilimycin, is a strong agonist of pregnane X receptor (PXR), a master regulator of xenobiotic detoxification and intestinal inflammation. Tilivalline binding upregulated PXR-responsive detoxifying genes and inhibited tubulin-directed toxicity. Bacterial indole, therefore, acts in a multifunctional manner to mitigate cytotoxicity by Klebsiella spp.: suppression of toxin production, enhanced conversion of tilimycin to tilivalline, and activation of PXR. IMPORTANCE The human gut harbors a complex community of microbes, including several species and strains that could be commensals or pathogens depending on context. The specific environmental conditions under which a resident microbe changes its relationship with a host and adopts pathogenic behaviors, in many cases, remain poorly understood. Here, we describe a novel communication network involving the regulation of K. grimontii and K. oxytoca enterotoxicity. Bacterial indole was identified as a central modulator of these colitogenic microbes by suppressing bacterial toxin (tilimycin) synthesis and converting tilimycin to tilivalline while simultaneously activating a host receptor, PXR, as a means of mitigating tissue cytotoxicity. On the other hand, fermentable carbohydrates were found to inhibit indole biosynthesis and enhance toxin production. This integrated network involving microbial, host, and metabolic factors provides a contextual framework to better understand K. oxytoca complex pathogenicity.

• Klíčová slova
• Klebsiella oxytoca complex, cytotoxin, indole, intestinal inflammation, pregnane X receptor,
• MeSH
• cytotoxiny metabolismus   MeSH
• enterotoxiny metabolismus   MeSH
• indoly metabolismus   MeSH
• infekce bakteriemi rodu Klebsiella * mikrobiologie   MeSH
• Klebsiella oxytoca genetika   metabolismus   MeSH
• lidé MeSH
• novorozenec MeSH
• pseudomembranózní enterokolitida * mikrobiologie   MeSH
• Check Tag
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• cytotoxiny MeSH
• enterotoxiny MeSH
• indoly MeSH

Recent advancement in manipulation techniques of gut microbiota either ex vivo or in situ has broadened its plausible applicability for treating various diseases including cardiovascular disease. Several reports suggested that altering gut microbiota composition is an effective way to deal with issues associated with managing cardiovascular diseases. However, actual translation of gut microbiota manipulation-based techniques into cardiovascular-therapeutic approach is still questionable. This review summarized the evidence on challenges, opportunities, recent development, and future prospects of gut microbiota manipulation for targeting cardiovascular diseases. Initially, issues associated with current cardiovascular diseases treatment strategy, association of gut microbiota with cardiovascular disease, and its influence on cardiovascular drugs were discussed, followed by applicability of gut microbiota manipulation as a cardiovascular disease intervention strategy along with its challenges and future prospects. Despite the fact that the gut microbiota is rugged, interventions like probiotics, prebiotics, synbiotics, fecal microbiota transplantation, fecal virome transplantation, antibiotics, diet changes, and exercises could manipulate it. Advanced techniques like administration of engineered bacteriophages and bacteria could also be employed. Intensive exploration revealed that if sufficiently controlled approach and proper monitoring were applied, gut microbiota could provide a compelling answer for cardiovascular therapy.

• MeSH
• fekální transplantace MeSH
• kardiovaskulární nemoci * terapie   MeSH
• lidé MeSH
• prebiotika MeSH
• probiotika * MeSH
• střevní mikroflóra * MeSH
• synbiotika * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• prebiotika MeSH

National screening programs use dried blood specimens to detect metabolic disorders or aberrant protein functions that are not clinically evident in the neonatal period. Similarly, gut microbiota metabolites and immunological acute-phase proteins may reveal latent immune aberrations. Microbial metabolites interact with xenobiotic receptors (i.e., aryl hydrocarbon and pregnane-X) to maintain gastrointestinal tissue health, supported by acute-phase proteins, functioning as sensors of microbial immunomodulation and homeostasis. The delivery (vaginal or cesarean section) shapes the microbial colonization, which substantially modulates both the immune system's response and mucosal homeostasis. This study profiled microbial metabolites of the kynurenine and tryptophan pathway and acute-phase proteins in 134 neonatal dried blood specimens. We newly established neonatal blood levels of microbial xenobiotic receptors ligands (i.e., indole-3-aldehyde, indole-3-butyric acid, and indole-3-acetamide) on the second day of life. Furthermore, we observed diverse microbial metabolic profiles in neonates born vaginally and via cesarean section, potentially due to microbial immunomodulatory influence. In summary, these findings suggest the supportive role of human gut microbiota in developing and maintaining immune system homeostasis.

• Klíčová slova
• acute-phase proteins, dried blood specimens, human gut microbiota, immunomodulation, tryptophan and kynurenine metabolism,
• Publikační typ
• časopisecké články MeSH

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.

• Klíčová slova
• GPR81, SCFA, colorectal cancer, functional food, intestinal metabolome, microbiome,
• 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
• Názvy látek
• beta-glukany MeSH
• butyráty MeSH
• kyselina mléčná MeSH
• kyseliny mastné těkavé MeSH
• prebiotika MeSH
• sulfan MeSH

The development of non-genotoxic therapies that activate wild-type p53 in tumors is of great interest since the discovery of p53 as a tumor suppressor. Here we report the identification of over 100 small-molecules activating p53 in cells. We elucidate the mechanism of action of a chiral tetrahydroindazole (HZ00), and through target deconvolution, we deduce that its active enantiomer (R)-HZ00, inhibits dihydroorotate dehydrogenase (DHODH). The chiral specificity of HZ05, a more potent analog, is revealed by the crystal structure of the (R)-HZ05/DHODH complex. Twelve other DHODH inhibitor chemotypes are detailed among the p53 activators, which identifies DHODH as a frequent target for structurally diverse compounds. We observe that HZ compounds accumulate cancer cells in S-phase, increase p53 synthesis, and synergize with an inhibitor of p53 degradation to reduce tumor growth in vivo. We, therefore, propose a strategy to promote cancer cell killing by p53 instead of its reversible cell cycle arresting effect.

• MeSH
• antitumorózní látky farmakologie   MeSH
• buněčný cyklus účinky léků   MeSH
• dihydroorotátdehydrogenasa MeSH
• indazoly farmakologie   MeSH
• inhibitory enzymů farmakologie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 genetika   metabolismus   MeSH
• nádory farmakoterapie   enzymologie   genetika   metabolismus   MeSH
• oxidoreduktasy působící na CH-CH vazby antagonisté a inhibitory   chemie   genetika   metabolismus   MeSH
• proliferace buněk účinky léků   MeSH
• proteolýza účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• antitumorózní látky MeSH
• dihydroorotátdehydrogenasa MeSH
• indazoly MeSH
• inhibitory enzymů MeSH
• nádorový supresorový protein p53 MeSH
• oxidoreduktasy působící na CH-CH vazby MeSH