RESUMEN
Although biosynthetic gene clusters (BGCs) have been discovered for hundreds of bacterial metabolites, our knowledge of their diversity remains limited. Here, we used a novel algorithm to systematically identify BGCs in the extensive extant microbial sequencing data. Network analysis of the predicted BGCs revealed large gene cluster families, the vast majority uncharacterized. We experimentally characterized the most prominent family, consisting of two subfamilies of hundreds of BGCs distributed throughout the Proteobacteria; their products are aryl polyenes, lipids with an aryl head group conjugated to a polyene tail. We identified a distant relationship to a third subfamily of aryl polyene BGCs, and together the three subfamilies represent the largest known family of biosynthetic gene clusters, with more than 1,000 members. Although these clusters are widely divergent in sequence, their small molecule products are remarkably conserved, indicating for the first time the important roles these compounds play in Gram-negative cell biology.
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Algoritmos , Bacterias/genética , Bacterias/metabolismo , Bacterias/química , Bacterias/clasificación , Mutación , Estrés Oxidativo , Filogenia , Metabolismo SecundarioRESUMEN
The molecular mechanisms by which dietary fruits and vegetables confer cardiometabolic benefits remain poorly understood. Historically, these beneficial properties have been attributed to the antioxidant activity of flavonoids. Here, we reveal that the host metabolic benefits associated with flavonoid consumption hinge, in part, on gut microbial metabolism. Specifically, we show that a single gut microbial flavonoid catabolite, 4-hydroxyphenylacetic acid (4-HPAA), is sufficient to reduce diet-induced cardiometabolic disease (CMD) burden in mice. The addition of flavonoids to a high fat diet heightened the levels of 4-HPAA within the portal plasma and attenuated obesity, and continuous delivery of 4-HPAA was sufficient to reverse hepatic steatosis. The antisteatotic effect was shown to be associated with the activation of AMP-activated protein kinase α (AMPKα). In a large survey of healthy human gut metagenomes, just over one percent contained homologs of all four characterized bacterial genes required to catabolize flavonols into 4-HPAA. Our results demonstrate the gut microbial contribution to the metabolic benefits associated with flavonoid consumption and underscore the rarity of this process in human gut microbial communities.
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Hígado Graso , Microbioma Gastrointestinal , Humanos , Ratones , Animales , Polifenoles/farmacología , Microbioma Gastrointestinal/fisiología , Hígado Graso/prevención & control , Obesidad/metabolismo , Dieta Alta en Grasa/efectos adversos , Flavonoides/farmacologíaRESUMEN
The gut microbiota produce specialized metabolites that are important for maintaining host health homeostasis. Hence, unstable production of these metabolites can contribute to diseases such as inflammatory bowel disease and colon cancer. While fecal transplantation or dietary modification approaches can be used to correct the gut microbial community's metabolic output, this Perspective focuses on the use of engineered bacteria. We highlight recent advances in bacterial synthetic biology approaches for the treatment of colorectal cancer and systemic tumors and discuss the functionality and biochemical properties of novel containment approaches using hydrogel-based and electronic devices. Synthetic circuitry refinement and incorporation of novel functional modules have enabled more targeted detection of colonic tumors and delivery of anticancer compounds inside the gastrointestinal (GI) tract, as well as the design of tumor-homing bacteria capable of recruiting infiltrating T cells. Engineering challenges in these applications include the stability of the genetic circuits, long-term engraftment of the chosen chassis, and containment of the synthetic microbes' activity to the diseased tissues. Hydrogels are well-suited to the encapsulationo of living organisms due to their matrix structure and tunable porosity. The matrix structure allows a dried hydrogel to collect and contain GI contents. Engineered bacteria that sense GI tract inflammation or tumors and release bioactive metabolites to the targeted area can be encapsulated. Electronic devices can be enabled with additional measuring and data processing capabilities. We expect that engineered devices will become more important in the containment and delivery of synthetic microbes for diagnostic and therapeutic applications.
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Neoplasias del Colon , Microbioma Gastrointestinal , Microbiota , Humanos , Bacterias/metabolismo , Hidrogeles/metabolismoRESUMEN
Cardiometabolic disease (CMD) is a leading cause of death worldwide and encompasses the inflammatory metabolic disorders of obesity, type 2 diabetes mellitus, nonalcoholic fatty liver disease, and cardiovascular disease. Flavonoids are polyphenolic plant metabolites that are abundantly present in fruits and vegetables and have biologically relevant protective effects in a number of cardiometabolic disorders. Several epidemiological studies underscored a negative association between dietary flavonoid consumption and the propensity to develop CMD. Recent studies elucidated the contribution of the gut microbiota in metabolizing dietary intake as it relates to CMD. Importantly, the biological efficacy of flavonoids in humans and animal models alike is linked to the gut microbial community. Herein, we discuss the opportunities and challenges of leveraging flavonoid intake as a potential strategy to prevent and treat CMD in a gut microbe-dependent manner, with special emphasis on flavonoid-derived microbial metabolites.
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Enfermedades Cardiovasculares , Diabetes Mellitus Tipo 2 , Microbioma Gastrointestinal , Enfermedades Metabólicas , Animales , Enfermedades Cardiovasculares/etiología , Enfermedades Cardiovasculares/prevención & control , Diabetes Mellitus Tipo 2/metabolismo , Flavonoides/farmacología , Flavonoides/uso terapéutico , HumanosRESUMEN
A mechanistic understanding of microbe-host interactions is critical to developing therapeutic strategies for targeted modulation of the host immune system. Different members of the gut symbiont species Lactobacillus reuteri modulate host health by, for example, reduction of intestinal inflammation. Previously, it was shown that L. reuteri activates the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that plays an important role in the mucosal immune system, by the production of tryptophan catabolites. Here, we identified a novel pathway by which L. reuteri activates AhR, which is independent of tryptophan metabolism. We screened a library of 36 L. reuteri strains and determined that R2lc and 2010, strains with a pigmented phenotype, are potent AhR activators. By whole-genome sequencing and comparative genomics, we identified genes unique to R2lc and 2010. Our analyses demonstrated that R2lc harbors two genetically distinct polyketide synthase (PKS) clusters, functionally unknown (fun) and pks, each carried by a multicopy plasmid. Inactivation of pks, but not fun, abolished the ability of R2lc to activate AhR. L. reuteri 2010 has a gene cluster homologous to the pks cluster in R2lc with an identical gene organization, which is also responsible for AhR activation. In conclusion, we identified a novel PKS pathway in L. reuteri R2lc and 2010 that is responsible for AhR activation.IMPORTANCE Temporary changes in the composition of the microbiota, for example, by oral administration of probiotics, can modulate the host immune system. However, the underlying mechanisms by which probiotics interact with the host are often unknown. Here, we show that Lactobacillus reuteri R2lc and 2010 harbor an orthologous PKS gene cluster that activates the aryl hydrocarbon receptor (AhR). AhR is a ligand-activated transcription factor that plays a key role in a variety of diseases, including amelioration of intestinal inflammation. Understanding the mechanism by which a bacterium modulates the immune system is critical for applying rational selection strategies for probiotic supplementation. Finally, heterologous and/or optimized expression of PKS is a logical next step toward the development of next-generation probiotics to prevent and treat disease.
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Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Limosilactobacillus reuteri/genética , Sintasas Poliquetidas/metabolismo , Receptores de Hidrocarburo de Aril/genética , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Línea Celular Tumoral , Microbioma Gastrointestinal , Limosilactobacillus reuteri/metabolismo , Ratones , Sintasas Poliquetidas/genética , Receptores de Hidrocarburo de Aril/metabolismo , SimbiosisRESUMEN
BACKGROUND: Recent advances in genome sequencing, combined with bioinformatic analysis, has led to the identification of numerous novel natural product gene clusters, particularly in actinomycetes of terrestrial and marine origin. Many of these gene clusters encode uncharacterised Type III polyketide synthases. To facilitate the study of these genes and their potentially novel products, we set out to construct an actinomycete expression host specifically designed for the heterologous expression of Type III PKS genes and their gene clusters. RESULTS: A derivative of Streptomyces coelicolor A3(2) designed for the expression of Type III polyketide synthase (PKS) genes was constructed from the previously engineered expression strain S. coelicolor M1152 [Δact Δred Δcpk Δcda rpoB(C1298T)] by removal of all three of the endogenous Type III PKS genes (gcs, srsA, rppA) by PCR targeting. The resulting septuple deletion mutant, M1317, proved to be an effective surrogate host for the expression of actinobacterial Type III PKS genes: expression of the reintroduced gcs gene from S. coelicolor and of the heterologous rppA gene from Streptomyces venezuelae under the control of the constitutive ermE* promoter resulted in copious production of germicidin and flaviolin, respectively. CONCLUSIONS: The newly constructed expression host S. coelicolor M1317 should be particularly useful for the discovery and analysis of new Type III polyketide metabolites.
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Familia de Multigenes , Sintasas Poliquetidas/genética , Streptomyces coelicolor/genética , Reactores Biológicos , Ingeniería Genética , Mutagénesis Sitio-Dirigida , Naftoquinonas/metabolismo , Organismos Modificados Genéticamente/metabolismo , Sintasas Poliquetidas/metabolismo , Pironas/metabolismo , Streptomyces coelicolor/metabolismoRESUMEN
Lantibiotic synthetases are remarkable biocatalysts generating conformationally constrained peptides with a variety of biological activities by repeatedly utilizing two simple posttranslational modification reactions: dehydration of Ser/Thr residues and intramolecular addition of Cys thiols to the resulting dehydro amino acids. Since previously reported lantibiotic synthetases show no apparent homology with any other known protein families, the molecular mechanisms and evolutionary origin of these enzymes are unknown. In this study, we present a novel class of lanthionine synthetases, termed LanL, that consist of three distinct catalytic domains and demonstrate in vitro enzyme activity of a family member from Streptomyces venezuelae. Analysis of individually expressed and purified domains shows that LanL enzymes install dehydroamino acids via phosphorylation of Ser/Thr residues by a protein kinase domain and subsequent elimination of the phosphate by a phosphoSer/Thr lyase domain. The latter has sequence homology with the phosphothreonine lyases found in various pathogenic bacteria that inactivate host mitogen activated protein kinases. A LanC-like cyclase domain then catalyzes the addition of Cys residues to the dehydro amino acids to form the characteristic thioether rings. We propose that LanL enzymes have evolved from stand-alone protein Ser/Thr kinases, phosphoSer/Thr lyases, and enzymes catalyzing thiol alkylation. We also demonstrate that the genes for all three pathways to lanthionine-containing peptides are widespread in Nature. Given the remarkable efficiency of formation of lanthionine-containing polycyclic peptides and the latter's high degree of specificity for their cognate cellular targets, it is perhaps not surprising that (at least) three distinct families of polypeptide sequences have evolved to access this structurally and functionally diverse class of compounds.
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Alanina/análogos & derivados , Proteínas Bacterianas , Bacteriocinas/metabolismo , Isoenzimas , Ligasas , Sulfuros/metabolismo , Alanina/química , Alanina/metabolismo , Secuencia de Aminoácidos , Bacterias/clasificación , Bacterias/enzimología , Bacterias/genética , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Bacteriocinas/química , Evolución Molecular , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Ligasas/química , Ligasas/genética , Ligasas/metabolismo , Datos de Secuencia Molecular , Estructura Molecular , Familia de Multigenes , Filogenia , Conformación Proteica , Procesamiento Proteico-Postraduccional , ARN Ribosómico 16S/genética , Alineación de Secuencia , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Streptomyces/enzimología , Streptomyces/genética , Sulfuros/químicaRESUMEN
Posttranslational modification of amino acids confers a range of structural features and activities on ribosomally synthesized peptides, many of which have potent antimicrobial or other biological activities. Cypemycin is an extensively modified linear peptide produced by Streptomyces sp. OH-4156 with potent in vitro activity against mouse leukemia cells. Cypemycin does not contain lanthionine bridges but exhibits some of the structural features of lantibiotics, notably dehydrated threonines (dehydrobutyrines) and a C-terminal S-[(Z)-2-aminovinyl]-D-cysteine. Consequently it was classified as a member of the lantibiotic family of posttranslationally modified peptides. Cypemycin also possesses two L-allo-isoleucine residues and an N-terminal N,N-dimethylalanine, both unique amino acid modifications. We identified and heterologously expressed the cypemycin biosynthetic gene cluster and performed a mutational analysis of each individual gene. We show that even the previously described modifications are carried out by unusual enzymes or via a modification pathway unrelated to lantibiotic biosynthesis. Bioinformatic analysis revealed the widespread occurrence of cypemycin-like gene clusters within the bacterial kingdom and in the Archaea. Cypemycin is the founding member of an unusual class of posttranslationally modified ribosomally synthesized peptides, the linaridins.
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Antibacterianos/biosíntesis , Proteínas Bacterianas/metabolismo , Bacteriocinas/biosíntesis , Genoma Bacteriano , Procesamiento Proteico-Postraduccional , Streptomyces/genética , Streptomyces/metabolismo , Secuencia de Aminoácidos , Antibacterianos/química , Proteínas Bacterianas/química , Bacteriocinas/química , Datos de Secuencia Molecular , Familia de Multigenes , Mutación , Péptidos/química , Péptidos/metabolismo , Streptomyces/químicaRESUMEN
Gut bacteria-driven production of trimethylamine (TMA) is strongly associated with cardiovascular disease. Borton et al. (mBio 14:e01511-23, 2023, https://doi.org/10.1128/mbio.01511-23) introduce the Methylated Amine Gene Inventory of Catabolism database (MAGICdb), comprehensively cataloging pathways involved in TMA metabolism. By integrating transcriptomics, proteomics, and metagenomic data, this work identifies key bacterial players in the process and can link gut microbial gene content to fecal TMA concentrations. This work shows that methylated amine metabolism is a keystone microbiome process carried out by a small proportion of the community. Proatherogenic pathways are more widely distributed among the gut microbiota, and new TMA-reducing genera were identified that might offer new potential for probiotic strategies or targeted microbiome interventions. Remarkably, MAGICdb's power to predict cardiovascular disease risk matches an approach using more traditional lipid risk factors. This open source will be a valuable tool for the community to link methylated amine metabolism to gut microbiome-related human health conditions.
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Bacterias/genética , Biología Computacional/normas , Hongos/genética , Familia de Multigenes , Plantas/genética , Biosíntesis de Proteínas , Alcaloides/biosíntesis , Bacterias/metabolismo , Bases de Datos Genéticas , Hongos/metabolismo , Marcadores Genéticos , Cooperación Internacional , Metagenoma , Biosíntesis de Péptidos Independientes de Ácidos Nucleicos , Péptidos/metabolismo , Plantas/metabolismo , Policétidos/metabolismo , Polisacáridos/biosíntesis , Terminología como Asunto , Terpenos/metabolismoRESUMEN
Accurate and reproducible analysis of murine small and large intestinal tissue is key for preclinical models involving intestinal pathology. Currently, there is no easily accessible, standardized method that allows researchers of different skill levels to consistently dissect intestines in a time-efficient manner. Here, we describe the design and use of the 3D-printed "Mouse Intestinal Slicing Tool" (MIST), which can be used to longitudinally dissect murine intestines for further analysis. We benchmarked the MIST against a commonly used procedure involving scissors to make a longitudinal cut along the intestines. Use of the MIST halved the time per mouse to prepare the intestines and outperformed alternative methods in smoothness of the cutting edge and overall reproducibility. By sharing the plans for printing the MIST, we hope to contribute a uniformly applicable method for saving time and increasing consistency in studies of the mouse gastrointestinal tract.
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Intestinos , Impresión Tridimensional , Animales , Ratones , Reproducibilidad de los ResultadosRESUMEN
The mammalian microbiome encodes numerous secondary metabolite biosynthetic gene clusters; yet, their role in microbe-microbe interactions is unclear. Here, we characterized two polyketide synthase gene clusters (fun and pks) in the gut symbiont Limosilactobacillus reuteri. The pks, but not the fun, cluster encodes antimicrobial activity. Forty-one of 51 L. reuteri strains tested are sensitive to Pks products; this finding was independent of strains' host origin. Sensitivity to Pks was also established in intraspecies competition experiments in gnotobiotic mice. Comparative genome analyses between Pks-resistant and -sensitive strains identified an acyltransferase gene (act) unique to Pks-resistant strains. Subsequent cell-wall analysis of wild-type and act mutant strains showed that Act acetylates cell-wall components, providing resistance to Pks-mediated killing. Additionally, pks mutants lost their competitive advantage, while act mutants lost their Pks resistance in in vivo competition assays. These findings provide insight into how closely related gut symbionts can compete and co-exist in the gastrointestinal tract.
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Familia de Multigenes , Sintasas Poliquetidas , Acetilación , Animales , Tracto Gastrointestinal/metabolismo , Vida Libre de Gérmenes , Mamíferos/genética , Ratones , Sintasas Poliquetidas/genética , Sintasas Poliquetidas/metabolismoRESUMEN
Epithelial ovarian cancer (EOC) is the leading cause of gynecologic cancer death. Despite initial responses to intervention, up to 80% of patient tumors recur and require additional treatment. Retrospective clinical analysis of patients with ovarian cancer indicates antibiotic use during chemotherapy treatment is associated with poor overall survival. Here, we assessed whether antibiotic (ABX) treatment would impact growth of EOC and sensitivity to cisplatin. Immunocompetent or immunocompromised mice were given untreated control or ABX-containing (metronidazole, ampicillin, vancomycin, and neomycin) water prior to intraperitoneal injection with EOC cells, and cisplatin therapy was administered biweekly until endpoint. Tumor-bearing ABX-treated mice exhibited accelerated tumor growth and resistance to cisplatin therapy compared with control treatment. ABX treatment led to reduced apoptosis, increased DNA damage repair, and enhanced angiogenesis in cisplatin-treated tumors, and tumors from ABX-treated mice contained a higher frequency of cisplatin-augmented cancer stem cells than control mice. Stool analysis indicated nonresistant gut microbial species were disrupted by ABX treatment. Cecal transplants of microbiota derived from control-treated mice was sufficient to ameliorate chemoresistance and prolong survival of ABX-treated mice, indicative of a gut-derived tumor suppressor. Metabolomics analyses identified circulating gut-derived metabolites that were altered by ABX treatment and restored by recolonization, providing candidate metabolites that mediate the cross-talk between the gut microbiome and ovarian cancer. Collectively, these findings indicate that an intact microbiome functions as a tumor suppressor in EOC, and perturbation of the gut microbiota with ABX treatment promotes tumor growth and suppresses cisplatin sensitivity. SIGNIFICANCE: Restoration of the gut microbiome, which is disrupted following antibiotic treatment, may help overcome platinum resistance in patients with epithelial ovarian cancer. See related commentary by Hawkins and Nephew, p. 4511.
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Microbioma Gastrointestinal , Neoplasias Ováricas , Humanos , Femenino , Ratones , Animales , Carcinoma Epitelial de Ovario/tratamiento farmacológico , Carcinoma Epitelial de Ovario/patología , Cisplatino/uso terapéutico , Estudios Retrospectivos , Recurrencia Local de Neoplasia/tratamiento farmacológico , Neoplasias Ováricas/patología , Antibacterianos/farmacologíaRESUMEN
Our recent identification and genetic analysis of the biosynthetic gene cluster for production of the ribosomally synthesized and posttranslationally modified peptide cypemycin revealed a new class of peptide natural products, the linaridins. Here we describe the identification and characterization of grisemycin, a linaridin produced by a previously unidentified gene cluster in Streptomyces griseus IFO 13350. Mass spectrometric analysis revealed that grisemycin possesses at least three of the modifications found in cypemycin, as well as an analogous leader peptidase cleavage site. Expression of putative grisemycin biosynthetic genes in a Streptomyces coelicolor A3(2) derivative, combined with deletion of the gene encoding the grisemycin precursor peptide, confirmed the identity of the grisemycin gene cluster. Both grisemycin and cypemycin depend on the transcriptional activator AdpA for wild-type levels of production.
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Proteínas Bacterianas/metabolismo , Vías Biosintéticas/genética , Regulación Bacteriana de la Expresión Génica , Streptomyces griseus/genética , Streptomyces griseus/metabolismo , Secuencia de Aminoácidos , Proteínas Bacterianas/química , Genes Bacterianos , Modelos Moleculares , Datos de Secuencia Molecular , Familia de Multigenes , Procesamiento Proteico-Postraduccional , Alineación de Secuencia , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
Aryl polyenes (APEs) are specialized polyunsaturated carboxylic acids that were identified in silico as the product of the most widespread family of bacterial biosynthetic gene clusters (BGCs). They are present in several Gram-negative host-associated bacteria, including multidrug-resistant human pathogens. Here, we characterize a biological function of APEs, focusing on the BGC from a uropathogenic Escherichia coli (UPEC) strain. We first perform a genetic deletion analysis to identify the essential genes required for APE biosynthesis. Next, we show that APEs function as fitness factors that increase protection from oxidative stress and contribute to biofilm formation. Together, our study highlights key steps in the APE biosynthesis pathway that can be explored as potential drug targets for complementary strategies to reduce fitness and prevent biofilm formation of multi-drug resistant pathogens.
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Biopelículas , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Genes Esenciales , Polienos/metabolismo , Biopelículas/crecimiento & desarrollo , Transporte Biológico , Vías Biosintéticas , Regulación Bacteriana de la Expresión Génica , Estructura Molecular , Mutación , Oxidación-Reducción , Fenotipo , Polienos/químicaRESUMEN
Gut microbe-derived metabolites influence human physiology and disease. However, establishing mechanistic links between gut microbial metabolites and disease pathogenesis in animal models remains challenging. The major route of absorption for microbe-derived small molecules is venous drainage via the portal vein to the liver. In the event of presystemic hepatic metabolism, the route of metabolite administration becomes critical. To our knowledge, we describe here a novel portal vein cannulation technique using a s.c. implanted osmotic pump to achieve continuous portal vein infusion in mice. We first administered the microbial metabolite trimethylamine (TMA) over 4 weeks, during which increased peripheral plasma levels of TMA and its host liver-derived cometabolite, trimethylamine-N-oxide, were observed when compared with a vehicle control. Next, 4-hydroxyphenylacetic acid (4-HPAA), a microbial metabolite that undergoes extensive presystemic hepatic metabolism, was administered intraportally to examine effects on hepatic gene expression. As expected, hepatic levels of 4-HPAA were elevated when compared with the control group while peripheral plasma 4-HPAA levels remained the same. Moreover, significant changes in the hepatic transcriptome were revealed by an unbiased RNA-Seq approach. Collectively, to our knowledge this work describes a novel method for administering gut microbe-derived metabolites via the portal vein, mimicking their physiologic delivery in vivo.
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Microbioma Gastrointestinal , Infusiones Intravenosas/métodos , Hígado/metabolismo , Metilaminas/administración & dosificación , Fenilacetatos/administración & dosificación , Vena Porta , Animales , Expresión Génica/efectos de los fármacos , Metilaminas/sangre , Metilaminas/metabolismo , Metilaminas/farmacología , Ratones , Fenilacetatos/sangre , Fenilacetatos/metabolismo , Fenilacetatos/farmacología , RNA-Seq , Transcriptoma/efectos de los fármacosRESUMEN
BACKGROUND: A major contributor to cardiometabolic disease is caloric excess, often a result of consuming low cost, high calorie fast food. Studies have demonstrated the pivotal role of gut microbes contributing to cardiovascular disease in a diet-dependent manner. Given the central contributions of diet and gut microbiota to cardiometabolic disease, we hypothesized that microbial metabolites originating after fast food consumption can elicit acute metabolic responses in the liver. METHODS: We gave conventionally raised mice or mice that had their microbiomes depleted with antibiotics a single oral gavage of a liquified fast food meal or liquified control rodent chow meal. After four hours, mice were sacrificed and we used untargeted metabolomics of portal and peripheral blood, 16S rRNA gene sequencing, targeted liver metabolomics, and host liver RNA sequencing to identify novel fast food-derived microbial metabolites and their acute effects on liver function. RESULTS: Several candidate microbial metabolites were enriched in portal blood upon fast food feeding, and were essentially absent in antibiotic-treated mice. Strikingly, at four hours post-gavage, fast food consumption resulted in rapid reorganization of the gut microbial community and drastically altered hepatic gene expression. Importantly, diet-driven reshaping of the microbiome and liver transcriptome was dependent on an intact microbial community and not observed in antibiotic ablated animals. CONCLUSIONS: Collectively, these data suggest a single fast food meal is sufficient to reshape the gut microbial community in mice, yielding a unique signature of food-derived microbial metabolites. Future studies are in progress to determine the contribution of select metabolites to cardiometabolic disease progression and the translational relevance of these animal studies.
RESUMEN
The composition of the skin microbiota varies widely among individuals when sampled at the same body site. A key question is which molecular factors determine strain-level variability within sub-ecosystems of the skin microbiota. Here, we used a genomics-guided approach to identify an antibacterial biosynthetic gene cluster in Cutibacterium acnes (formerly Propionibacterium acnes), a human skin commensal bacterium that is widely distributed across individuals and skin sites. Experimental characterization of this biosynthetic gene cluster resulted in identification of a new thiopeptide antibiotic, cutimycin. Analysis of individual human skin hair follicles revealed that cutimycin contributed to the ecology of the skin hair follicle microbiota and helped to reduce colonization of skin hair follicles by Staphylococcus species.
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Folículo Piloso , Microbiota , Antibacterianos/farmacología , Humanos , Propionibacterium acnes , PielRESUMEN
Sialic acid (N-acetylneuraminic acid (Neu5Ac)) is commonly found in the terminal location of colonic mucin glycans where it is a much-coveted nutrient for gut bacteria, including Ruminococcus gnavus. R. gnavus is part of the healthy gut microbiota in humans, but it is disproportionately represented in diseases. There is therefore a need to understand the molecular mechanisms that underpin the adaptation of R. gnavus to the gut. Previous in vitro research has demonstrated that the mucin-glycan-foraging strategy of R. gnavus is strain dependent and is associated with the expression of an intramolecular trans-sialidase, which releases 2,7-anhydro-Neu5Ac, rather than Neu5Ac, from mucins. Here, we unravelled the metabolism pathway of 2,7-anhydro-Neu5Ac in R. gnavus that is underpinned by the exquisite specificity of the sialic transporter for 2,7-anhydro-Neu5Ac and by the action of an oxidoreductase that converts 2,7-anhydro-Neu5Ac into Neu5Ac, which then becomes a substrate of a Neu5Ac-specific aldolase. Having generated an R. gnavus nan-cluster deletion mutant that lost the ability to grow on sialylated substrates, we showed that-in gnotobiotic mice colonized with R. gnavus wild-type (WT) and mutant strains-the fitness of the nan mutant was significantly impaired, with a reduced ability to colonize the mucus layer. Overall, we revealed a unique sialic acid pathway in bacteria that has important implications for the spatial adaptation of mucin-foraging gut symbionts in health and disease.
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Adaptación Fisiológica , Microbioma Gastrointestinal/fisiología , Moco/metabolismo , Ácido N-Acetilneuramínico/metabolismo , Ruminococcus/metabolismo , Animales , Clostridiales , Glicoproteínas , Humanos , Redes y Vías Metabólicas/genética , Redes y Vías Metabólicas/fisiología , Ratones , Ratones Endogámicos C57BL , Mucinas/metabolismo , Ácido N-Acetilneuramínico/análogos & derivados , Neuraminidasa , Oxo-Ácido-Liasas/metabolismo , Polisacáridos/metabolismo , Proteínas Recombinantes , Ruminococcus/enzimología , Ruminococcus/genéticaRESUMEN
The impact of antiseptics on the skin microbiota is poorly understood. SanMiguel et al. (2018) use a sequencing-based approach to compare treatment effects and find that they are dependent on interpersonal and body site-specific community differences. While treatment results in an immediate depletion of the skin microbiota, not all bacterial families are affected equally.