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1.
Elife ; 102021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34617511

RESUMO

East Asians experience worse metabolic health outcomes compared to other ethnic groups at lower body mass indices; however, the potential role of the gut microbiota in contributing to these health disparities remains unknown. We conducted a multi-omic study of 46 lean and obese East Asian and White participants living in the San Francisco Bay Area, revealing marked differences between ethnic groups in bacterial richness and community structure. White individuals were enriched for the mucin-degrading Akkermansia muciniphila. East Asian subjects had increased levels of multiple bacterial phyla, fermentative pathways detected by metagenomics, and the short-chain fatty acid end-products acetate, propionate, and isobutyrate. Differences in the gut microbiota between the East Asian and White subjects could not be explained by dietary intake, were more pronounced in lean individuals, and were associated with current geographical location. Microbiome transplantations into germ-free mice demonstrated stable diet- and host genotype-independent differences between the gut microbiotas of East Asian and White individuals that differentially impact host body composition. Taken together, our findings add to the growing body of literature describing variation between ethnicities and provide a starting point for defining the mechanisms through which the microbiome may shape disparate health outcomes in East Asians.

3.
Annu Rev Anal Chem (Palo Alto Calif) ; 14(1): 467-487, 2021 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-34314226

RESUMO

High-resolution mass spectrometry (MS) has advanced the study of metabolism in living systems by allowing many metabolites to be measured in a single experiment. Although improvements in mass detector sensitivity have facilitated the detection of greater numbers of analytes, compound identification strategies, feature reduction software, and data sharing have not kept up with the influx of MS data. Here, we discuss the ongoing challenges with MS-based metabolomics, including de novo metabolite identification from mass spectra, differentiation of metabolites from environmental contamination, chromatographic separation of isomers, and incomplete MS databases. Because of their popularity and sensitive detection of small molecules, this review focuses on the challenges of liquid chromatography-mass spectrometry-based methods. We then highlight important instrumentational, experimental, and computational tools that have been created to address these challenges and how they have enabled the advancement of metabolomics research.

4.
Pediatr Obes ; : e12833, 2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34327846

RESUMO

BACKGROUND: Metabolomic analysis is commonly used to understand the biological underpinning of diseases such as obesity. However, our knowledge of gut metabolites related to weight outcomes in young children is currently limited. OBJECTIVES: To (1) explore the relationships between metabolites and child weight outcomes, (2) determine the potential effect of covariates (e.g., child's diet, maternal health/habits during pregnancy, etc.) in the relationship between metabolites and child weight outcomes, and (3) explore the relationship between selected gut metabolites and gut microbiota abundance. METHODS: Using 1 H-NMR, we quantified 30 metabolites from stool samples of 170 two-year-old children. To identify metabolites and covariates associated with children's weight outcomes (BMI [weight/height2 ], BMI z-score [BMI adjusted for age and sex], and growth index [weight/height]), we analysed the 1 H-NMR data, along with 20 covariates recorded on children and mothers, using LASSO and best subset selection regression techniques. Previously characterized microbiota community information from the same stool samples was used to determine associations between selected gut metabolites and gut microbiota. RESULTS: At age 2 years, stool butyrate concentration had a significant positive association with child BMI (p-value = 3.58 × 10-4 ), BMI z-score (p-value = 3.47 × 10-4 ), and growth index (p-value = 7.73 × 10-4 ). Covariates such as maternal smoking during pregnancy are important to consider. Butyrate concentration was positively associated with the abundance of the bacterial genus Faecalibacterium (p-value = 9.61 × 10-3 ). CONCLUSIONS: Stool butyrate concentration is positively associated with increased child weight outcomes and should be investigated further as a factor affecting childhood obesity.

5.
Toxicology ; 458: 152831, 2021 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-34097992

RESUMO

Aryl hydrocarbon receptor (AHR) activation via 2,3,7,8-tetrachlorodibenzofuran (TCDF) induces the accumulation of hepatic lipids. Here we report that AHR activation by TCDF (24  µg/kg body weight given orally for five days) induced significant elevation of hepatic lipids including ceramides in mice, was associated with increased expression of key ceramide biosynthetic genes, and increased activity of their respective enzymes. Results from chromatin immunoprecipitation (ChIP), electrophoretic mobility shift assay (EMSA) and cell-based reporter luciferase assays indicated that AHR directly activated the serine palmitoyltransferase long chain base subunit 2 (Sptlc2, encodes serine palmitoyltransferase 2 (SPT2)) gene whose product catalyzes the initial rate-limiting step in de novo sphingolipid biosynthesis. Hepatic ceramide accumulation was further confirmed by mass spectrometry-based lipidomics. Taken together, our results revealed that AHR activation results in the up-regulation of Sptlc2, leading to ceramide accumulation, thus promoting lipogenesis, which can induce hepatic lipid accumulation.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Ceramidas/biossíntese , Lipogênese/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Receptores de Hidrocarboneto Arílico/metabolismo , Ativação Metabólica/efeitos dos fármacos , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Benzofuranos/farmacologia , Ceramidas/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Lipidômica , Fígado/enzimologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores de Hidrocarboneto Arílico/genética , Serina C-Palmitoiltransferase/genética , Serina C-Palmitoiltransferase/metabolismo , Esfingomielina Fosfodiesterase/metabolismo , Triglicerídeos/metabolismo
6.
Nature ; 595(7866): 272-277, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34163067

RESUMO

Diet is a major factor that shapes the gut microbiome1, but the consequences of diet-induced changes in the microbiome for host pathophysiology remain poorly understood. We conducted a randomized human intervention study using a very-low-calorie diet (NCT01105143). Although metabolic health was improved, severe calorie restriction led to a decrease in bacterial abundance and restructuring of the gut microbiome. Transplantation of post-diet microbiota to mice decreased their body weight and adiposity relative to mice that received pre-diet microbiota. Weight loss was associated with impaired nutrient absorption and enrichment in Clostridioides difficile, which was consistent with a decrease in bile acids and was sufficient to replicate metabolic phenotypes in mice in a toxin-dependent manner. These results emphasize the importance of diet-microbiome interactions in modulating host energy balance and the need to understand the role of diet in the interplay between pathogenic and beneficial symbionts.


Assuntos
Bactérias/isolamento & purificação , Bactérias/metabolismo , Restrição Calórica , Dieta Redutora , Microbioma Gastrointestinal/fisiologia , Adiposidade , Animais , Bactérias/crescimento & desenvolvimento , Bactérias/patogenicidade , Toxinas Bacterianas/metabolismo , Ácidos e Sais Biliares/metabolismo , Peso Corporal , Clostridioides difficile/crescimento & desenvolvimento , Clostridioides difficile/isolamento & purificação , Clostridioides difficile/metabolismo , Metabolismo Energético , Humanos , Absorção Intestinal , Masculino , Camundongos , Nutrientes/metabolismo , Simbiose , Perda de Peso
7.
PLoS One ; 16(2): e0246161, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33600468

RESUMO

Ursodeoxycholic acid (commercially available as ursodiol) is a naturally occurring bile acid that is used to treat a variety of hepatic and gastrointestinal diseases. Ursodiol can modulate bile acid pools, which have the potential to alter the gut microbiota community structure. In turn, the gut microbial community can modulate bile acid pools, thus highlighting the interconnectedness of the gut microbiota-bile acid-host axis. Despite these interactions, it remains unclear if and how exogenously administered ursodiol shapes the gut microbial community structure and bile acid pool in conventional mice. This study aims to characterize how ursodiol alters the gastrointestinal ecosystem in conventional mice. C57BL/6J wildtype mice were given one of three doses of ursodiol (50, 150, or 450 mg/kg/day) by oral gavage for 21 days. Alterations in the gut microbiota and bile acids were examined including stool, ileal, and cecal content. Bile acids were also measured in serum. Significant weight loss was seen in mice treated with the low and high dose of ursodiol. Alterations in the microbial community structure and bile acid pool were seen in ileal and cecal content compared to pretreatment, and longitudinally in feces following the 21-day ursodiol treatment. In both ileal and cecal content, members of the Lachnospiraceae Family significantly contributed to the changes observed. This study is the first to provide a comprehensive view of how exogenously administered ursodiol shapes the healthy gastrointestinal ecosystem in conventional mice. Further studies to investigate how these changes in turn modify the host physiologic response are important.


Assuntos
Peso Corporal , Microbioma Gastrointestinal , Receptores Citoplasmáticos e Nucleares/metabolismo , Ácido Ursodesoxicólico/farmacologia , Animais , Peso Corporal/efeitos dos fármacos , Ceco/microbiologia , Fezes/microbiologia , Feminino , Microbioma Gastrointestinal/efeitos dos fármacos , Íleo/microbiologia , Masculino , Metaboloma/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Receptores Acoplados a Proteínas G/metabolismo , Ácido Ursodesoxicólico/administração & dosagem , Perda de Peso/efeitos dos fármacos
8.
J Biol Chem ; 296: 100410, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33581115

RESUMO

Trace element selenium (Se) is incorporated as the 21st amino acid, selenocysteine, into selenoproteins through tRNA[Ser]Sec. Selenoproteins act as gatekeepers of redox homeostasis and modulate immune function to effect anti-inflammation and resolution. However, mechanistic underpinnings involving metabolic reprogramming during inflammation and resolution remain poorly understood. Bacterial endotoxin lipopolysaccharide (LPS) activation of murine bone marrow-derived macrophages cultured in the presence or absence of Se (as selenite) was used to examine temporal changes in the proteome and metabolome by multiplexed tandem mass tag-quantitative proteomics, metabolomics, and machine-learning approaches. Kinetic deltagram and clustering analysis indicated that addition of Se led to extensive reprogramming of cellular metabolism upon stimulation with LPS enhancing the pentose phosphate pathway, tricarboxylic acid cycle, and oxidative phosphorylation, to aid in the phenotypic transition toward alternatively activated macrophages, synonymous with resolution of inflammation. Remodeling of metabolic pathways and consequent metabolic adaptation toward proresolving phenotypes began with Se treatment at 0 h and became most prominent around 8 h after LPS stimulation that included succinate dehydrogenase complex, pyruvate kinase, and sedoheptulokinase. Se-dependent modulation of these pathways predisposed bone marrow-derived macrophages to preferentially increase oxidative phosphorylation to efficiently regulate inflammation and its timely resolution. The use of macrophages lacking selenoproteins indicated that all three metabolic nodes were sensitive to selenoproteome expression. Furthermore, inhibition of succinate dehydrogenase complex with dimethylmalonate affected the proresolving effects of Se by increasing the resolution interval in a murine peritonitis model. In summary, our studies provide novel insights into the role of cellular Se via metabolic reprograming to facilitate anti-inflammation and proresolution.


Assuntos
Selênio/metabolismo , Selenoproteínas/metabolismo , Animais , Suscetibilidade a Doenças/metabolismo , Inflamação/metabolismo , Inflamação/fisiopatologia , Lipopolissacarídeos/metabolismo , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Peritonite/tratamento farmacológico , Peritonite/imunologia , Proteoma/metabolismo , Proteômica , Selênio/farmacologia , Selenoproteínas/genética , Selenoproteínas/fisiologia , Succinato Desidrogenase/metabolismo
9.
Cell Host Microbe ; 29(3): 362-377.e11, 2021 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-33440172

RESUMO

Immunomodulatory drugs can inhibit bacterial growth, yet their mechanism of action, spectrum, and clinical relevance remain unknown. Methotrexate (MTX), a first-line rheumatoid arthritis (RA) treatment, inhibits mammalian dihydrofolate reductase (DHFR), but whether it directly impacts gut bacteria is unclear. We show that MTX broadly alters the human gut microbiota. Drug sensitivity varied across strains, but the mechanism of action against DHFR appears conserved between mammalian and bacterial cells. RA patient microbiotas were sensitive to MTX, and changes in gut bacterial taxa and gene family abundance were distinct between responders and non-responders. Transplantation of post-treatment samples into germ-free mice given an inflammatory trigger led to reduced immune activation relative to pre-treatment controls, enabling identification of MTX-modulated bacterial taxa associated with intestinal and splenic immune cells. Thus, conservation in cellular pathways across domains of life can result in broad off-target drug effects on the human gut microbiota with consequences for immune function.


Assuntos
Bactérias/metabolismo , Microbioma Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/imunologia , Metotrexato/metabolismo , Metotrexato/farmacologia , Animais , Artrite Reumatoide/imunologia , Doenças Autoimunes , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Feminino , Microbioma Gastrointestinal/imunologia , Humanos , Metabolômica , Camundongos , Camundongos Endogâmicos C57BL , Filogenia , Purinas/metabolismo , Pirimidinas/metabolismo , RNA Ribossômico 16S/genética , Tetra-Hidrofolato Desidrogenase , Transcriptoma
10.
Obes Surg ; 31(2): 773-780, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32986170

RESUMO

BACKGROUND: Bile acids have been implicated in the mechanism by which Roux-en-Y gastric bypass (RYGB) can induce remission of type 2 diabetes (T2D). Our goal was to identify circulating proteins whose levels changed after RYGB when dysglycemic parameters normalized. MATERIALS AND METHODS: This was a retrospective study of 26 participants who underwent RYGB. Blood proteins were identified using two-dimensional electrophoresis and mass spectroscopy. Complement proteins were measured using immunoassays and bile acids measured using ultra-high-performance liquid chromatography and mass spectroscopy. RESULTS: A total of 7/452 blood proteins were found to change 2 days after RYGB. Complement component 3 (C3) was selected because of its regulation by bile acids and the glucoregulatory function of its proteolytically processed product C3adesArg or acylation-stimulating protein (ASP). The median (inter-quartile range/IQR) C3 level was 47.4 (34.5, 65.9) mg/dL before surgery decreasing to 40.9 (13.4, 64.1) mg/dL within 2 days after surgery (p = 0.0292). The median (IQR) ASP level increased from 2.8 (0.9, 7.3) nM before surgery to 8.0 (5.3, 14.1) nM within 2 days after surgery (p = 0.0016). ASP levels increased in 14/17 (82%) with T2D remission and in 6/6 with normoglycemia but decreased in 3/3 with persistent T2D. Of ten bile acids measured, the levels of ursodeoxycholic acid (UDCA) were significantly decreased after RYGB and the levels of taurodeoxycholic acid (TDCA) were significantly decreased with T2D remission. CONCLUSIONS: These data further support an association of C3 with glucose metabolism and implicate bile acids and ASP in the early remittive effects of RYGB on T2D.


Assuntos
Diabetes Mellitus Tipo 2 , Derivação Gástrica , Obesidade Mórbida , Acilação , Ácidos e Sais Biliares , Glicemia , Complemento C3 , Diabetes Mellitus Tipo 2/cirurgia , Humanos , Obesidade Mórbida/cirurgia , Estudos Retrospectivos
11.
Methods Mol Biol ; 2194: 291-300, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32926372

RESUMO

Bile acids are important end products of cholesterol metabolism, having been shown to serve as signaling molecules and intermediates between the host and the gut microbiota. Here we describe a robust and accurate method using ultrahigh-pressure liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) for the quantification of bile acids in stool/cecal and tissue samples.


Assuntos
Ácidos e Sais Biliares/análise , Cromatografia Líquida de Alta Pressão/métodos , Metabolômica/métodos , Espectrometria de Massas em Tandem/métodos , Ácidos e Sais Biliares/sangue , Fezes/química , Intestinos/química , Fígado/química
12.
Methods Mol Biol ; 2194: 301-313, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32926373

RESUMO

NMR spectroscopy has become one of the preferred analytical techniques for metabolomics studies due to its inherent nondestructive nature, ability to identify and quantify metabolites simultaneously in a complex mixture, minimal sample preparation requirement, and high degree of experimental reproducibility. NMR-based metabolomics studies involve the measurement and multivariate statistical analysis of metabolites present in biological samples such as biofluids, stool/feces, intestinal content, tissue, and cell extracts by high-resolution NMR spectroscopy-the goal then is to identify and quantify metabolites and evaluate changes of metabolite concentrations in response to some perturbation. Here we describe methodologies for NMR sample preparation of biofluids (serum, saliva, and urine) and stool/feces, intestinal content, and tissues for NMR experiments including extraction of polar metabolites and application of NMR in metabolomics studies. One dimensional (1D) 1H NMR experiments with different variations such as pre-saturation, relaxation-edited, and diffusion-edited are routinely acquired for profiling and metabolite identification and quantification. 2D homonuclear 1H-1H TOCSY and COSY, 2D J-resolved, and heteronuclear 1H-13C HSQC and HMBC are also performed to assist with metabolite identification and quantification. The NMR data are then subjected to targeted and/or untargeted multivariate statistical analysis for biomarker discovery, clinical diagnosis, toxicological studies, molecular phenotyping, and functional genomics.


Assuntos
Espectroscopia de Ressonância Magnética/métodos , Metabolômica/métodos , Manejo de Espécimes/métodos , Animais , Líquidos Corporais/química , Fezes/química , Humanos , Análise Multivariada , Reprodutibilidade dos Testes , Saliva/química , Soro/química , Urina/química
13.
Gut Microbes ; 12(1): 1-16, 2020 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-33295235

RESUMO

Emerging evidence supports that exposure to persistent organic pollutants (POPs) can impact the interaction between the gut microbiota and host. Recent efforts have characterized the relationship between gut microbiota and environment pollutants suggesting additional research is needed to understand potential new avenues for toxicity. Here, we systematically examined the direct effects of POPs including 2,3,7,8-tetrachlorodibenzofuran (TCDF), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and polychlorinated biphenyls (PCB-123 and PCB-156) on the microbiota using metatranscriptomics and NMR- and mass spectrometry-based metabolomics combined with flow cytometry and growth rate measurements (OD600). This study demonstrated that (1) POPs directly and rapidly affect isolated cecal bacterial global metabolism that is associated with significant decreases in microbial metabolic activity; (2) significant changes in cecal bacterial gene expression related to tricarboxylic acid (TCA) cycle as well as carbon metabolism, carbon fixation, pyruvate metabolism, and protein export were observed following most POP exposure; (3) six individual bacterial species show variation in lipid metabolism in response to POP exposure; and (4) PCB-153 (non-coplanar)has a greater impact on bacteria than PCB-126 (coplanar) at the metabolic and transcriptional levels. These data provide new insights into the direct role of POPs on gut microbiota and begins to establish possible microbial toxicity endpoints which may help to inform risk assessment.

14.
J Exp Biol ; 223(Pt 19)2020 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-33051361

RESUMO

Most research on the impact of the gut microbiome on animal nutrition is designed to identify the effects of single microbial taxa and single metabolites of microbial origin, without considering the potentially complex network of interactions among co-occurring microorganisms. Here, we investigated how different microbial associations and their fermentation products affect host nutrition, using Drosophila melanogaster colonized with three gut microorganisms (the bacteria Acetobacter fabarum and Lactobacillus brevis, and the yeast Hanseniaspora uvarum) in all seven possible combinations. Some microbial effects on host traits could be attributed to single taxa (e.g. yeast-mediated reduction of insect development time), while other effects were sex specific and driven by among-microbe interactions (e.g. male lipid content determined by interactions between the yeast and both bacteria). Parallel analysis of nutritional indices of microbe-free flies administered different microbial fermentation products (acetic acid, acetoin, ethanol and lactic acid) revealed a single consistent effect: that the lipid content of both male and female flies is reduced by acetic acid. This effect was recapitulated in male flies colonized with both yeast and A. fabarum, but not for any microbial treatment in females or males with other microbial complements. These data suggest that the effect of microbial fermentation products on host nutritional status is strongly context dependent, with respect to both the combination of associated microorganisms and host sex. Taken together, our findings demonstrate that among-microbe interactions can play a critically important role in determining the physiological outcome of host-microbiome interactions in Drosophila and, likely, in other animal hosts.


Assuntos
Acetobacter , Microbioma Gastrointestinal , Animais , Drosophila melanogaster , Feminino , Hanseniaspora , Masculino
15.
Artigo em Inglês | MEDLINE | ID: mdl-32882426

RESUMO

Nonalcoholic fatty liver disease is the leading cause of liver disease worldwide and can progress to nonalcoholic steatohepatitis (NASH) through physical inactivity and gut dysbiosis.1 Exercise training reverses gut dysbiosis in non-NASH persons with obesity and in NASH animal models.2,3 Consequently, we conducted a proof-of-concept study investigating the effect of exercise training on gut dysbiosis in NASH patients.

16.
Gut Microbes ; 12(1): 1-24, 2020 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-32783770

RESUMO

Commensal microbiota-dependent tryptophan catabolism within the gastrointestinal tract is known to exert profound effects upon host physiology, including the maintenance of epithelial barrier and immune function. A number of abundant microbiota-derived tryptophan metabolites exhibit activation potential for the aryl hydrocarbon receptor (AHR). Gene expression facilitated by AHR activation through the presence of dietary or microbiota-generated metabolites can influence gastrointestinal homeostasis and confer protection from intestinal challenges. Utilizing untargeted mass spectrometry-based metabolomics profiling, combined with AHR activity screening assays, we identify four previously unrecognized tryptophan metabolites, present in mouse cecal contents and human stool, with the capacity to activate AHR. Using GC/MS and LC/MS platforms, quantification of these novel AHR activators, along with previously established AHR-activating tryptophan metabolites, was achieved, providing a relative order of abundance. Using physiologically relevant concentrations and quantitative gene expression analyses, the relative efficacy of these tryptophan metabolites with regard to mouse or human AHR activation potential is examined. These data reveal indole, 2-oxindole, indole-3-acetic acid and kynurenic acid as the dominant AHR activators in mouse cecal contents and human stool from participants on a controlled diet. Here we provide the first documentation of the relative abundance and AHR activation potential of a panel of microbiota-derived tryptophan metabolites. Furthermore, these data reveal the human AHR to be more sensitive, at physiologically relevant concentrations, to tryptophan metabolite activation than mouse AHR. Additionally, correlation analyses indicate a relationship linking major tryptophan metabolite abundance with AHR activity, suggesting these cecal/fecal metabolites represent biomarkers of intestinal AHR activity.

17.
Metabolites ; 10(8)2020 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-32796650

RESUMO

Non-alcoholic steatohepatitis (NASH) represents the progressive sub-disease of non-alcoholic fatty liver disease that causes chronic liver injury initiated and sustained by steatosis and necroinflammation. The Ron receptor is a tyrosine kinase of the Met proto-oncogene family that potentially has a beneficial role in adipose and liver-specific inflammatory responses, as well as glucose and lipid metabolism. Since its discovery two decades ago, the Ron receptor has been extensively investigated for its differential roles on inflammation and cancer. Previously, we showed that Ron expression on tissue-resident macrophages limits inflammatory macrophage activation and promotes a repair phenotype, which can retard the progression of NASH in a diet-induced mouse model. However, the metabolic consequences of Ron activation have not previously been investigated. Here, we explored the effects of Ron receptor activation on major metabolic pathways that underlie the development and progression of NASH. Mice lacking apolipoprotein E (ApoE KO) and double knockout (DKO) mice that lack ApoE and Ron were maintained on a high-fat high-cholesterol diet for 18 weeks. We observed that, in DKO mice, the loss of ligand-dependent Ron signaling aggravated key pathological features in steatohepatitis, including steatosis, inflammation, oxidation stress, and hepatocyte damage. Transcriptional programs positively regulating fatty acid (FA) synthesis and uptake were upregulated in the absence of Ron receptor signaling, whereas lipid disposal pathways were downregulated. Consistent with the deregulation of lipid metabolism pathways, the DKO animals exhibited increased accumulation of FAs in the liver and decreased level of bile acids. Altogether, ligand-dependent Ron receptor activation provides protection from the deregulation of major metabolic pathways that initiate and aggravate non-alcoholic steatohepatitis.

18.
Physiol Genomics ; 52(8): 314-321, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32628083

RESUMO

Lipocalin 2 (Lcn2) is a multifunctional innate immune protein that limits microbial overgrowth. Our previous study demonstrated that the gut microbiota directly induces intestinal Lcn2 production, and Lcn2-deficient (Lcn2-/-) mice exhibit gut dysbiosis. Coincidentally, gut dysbiosis is associated with metabolic syndrome pathogenesis, and elevated Lcn2 levels has been considered a potential clinical biomarker of metabolic syndrome. Yet whether Lcn2 mitigates or exacerbates metabolic syndrome remains inconclusive. Our objective was to determine whether Lcn2 deficiency-induced compositional changes in gut microbiota contribute to gain in adiposity in aged mice. Utilizing Lcn2-/- mice and their wild-type (WT) littermates, we measured metabolic markers, including fasting blood glucose, serum lipids, fat pad weight, and insulin resistance at ages 3, 6, and 9 mo old. Relative to WT mice, aged Lcn2-/- mice exhibited a gain in adiposity associated with numerous features of metabolic syndrome, including insulin resistance and dyslipidemia. Surprisingly, supplementation with a high-fat diet did not further aggravate metabolic syndrome that spontaneously occurs in Lcn2-/- mice by 6 mo of age. Interestingly, chow-fed Lcn2-/- mice displayed marked differences in the bacterial abundance and metabolomic profile of the gut microbiota compared with WT mice. Overall, our results demonstrate that Lcn2 is essential to maintain metabolic and gut microbiotal homeostasis, where deficiency induces spontaneous delayed onset of metabolic syndrome.


Assuntos
Envelhecimento/metabolismo , Disbiose/complicações , Disbiose/metabolismo , Dislipidemias/complicações , Microbioma Gastrointestinal/genética , Lipocalina-2/deficiência , Síndrome Metabólica/complicações , Síndrome Metabólica/metabolismo , Tecido Adiposo , Adiposidade/genética , Animais , Glicemia/análise , Dieta Hiperlipídica , Modelos Animais de Doenças , Disbiose/sangue , Disbiose/microbiologia , Dislipidemias/sangue , Dislipidemias/microbiologia , Feminino , Microbioma Gastrointestinal/imunologia , Homeostase/genética , Lipocalina-2/genética , Masculino , Síndrome Metabólica/sangue , Síndrome Metabólica/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/metabolismo
19.
mBio ; 11(4)2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32665268

RESUMO

Beneficial microorganisms associated with animals derive their nutritional requirements entirely from the animal host, but the impact of these microorganisms on host metabolism is largely unknown. The focus of this study was the experimentally tractable tripartite symbiosis between the pea aphid Acyrthosiphon pisum, its obligate intracellular bacterial symbiont Buchnera, and the facultative bacterium Hamiltonella which is localized primarily to the aphid hemolymph (blood). Metabolome experiments on, first, multiple aphid genotypes that naturally bear or lack Hamiltonella and, second, one aphid genotype from which Hamiltonella was experimentally eliminated revealed no significant effects of Hamiltonella on aphid metabolite profiles, indicating that Hamiltonella does not cause major reconfiguration of host metabolism. However, the titer of just one metabolite, 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), displayed near-significant enrichment in Hamiltonella-positive aphids in both metabolome experiments. AICAR is a by-product of biosynthesis of the essential amino acid histidine in Buchnera and, hence, an index of histidine biosynthetic rates, suggesting that Buchnera-mediated histidine production is elevated in Hamiltonella-bearing aphids. Consistent with this prediction, aphids fed on [13C]histidine yielded a significantly elevated 12C/13C ratio of histidine in Hamiltonella-bearing aphids, indicative of increased (∼25%) histidine synthesized de novo by Buchnera However, in silico analysis predicted an increase of only 0.8% in Buchnera histidine synthesis in Hamiltonella-bearing aphids. We hypothesize that Hamiltonella imposes increased host demand for histidine, possibly for heightened immune-related functions. These results demonstrate that facultative bacteria can alter the dynamics of host metabolic interactions with co-occurring microorganisms, even when the overall metabolic homeostasis of the host is not substantially perturbed.IMPORTANCE Although microbial colonization of the internal tissues of animals generally causes septicemia and death, various animals are persistently associated with benign or beneficial microorganisms in their blood or internal organs. The metabolic consequences of these persistent associations for the animal host are largely unknown. Our research on the facultative bacterium Hamiltonella, localized primarily to the hemolymph of pea aphids, demonstrated that although Hamiltonella imposed no major reconfiguration of the aphid metabolome, it did alter the metabolic relations between the aphid and its obligate intracellular symbiont, Buchnera Specifically, Buchnera produced more histidine in Hamiltonella-positive aphids to support both Hamiltonella demand for histidine and Hamiltonella-induced increase in host demand. This study demonstrates how microorganisms associated with internal tissues of animals can influence specific aspects of metabolic interactions between the animal host and co-occurring microorganisms.

20.
Cell ; 181(6): 1263-1275.e16, 2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32437658

RESUMO

Very low-carbohydrate, high-fat ketogenic diets (KDs) induce a pronounced shift in metabolic fuel utilization that elevates circulating ketone bodies; however, the consequences of these compounds for host-microbiome interactions remain unknown. Here, we show that KDs alter the human and mouse gut microbiota in a manner distinct from high-fat diets (HFDs). Metagenomic and metabolomic analyses of stool samples from an 8-week inpatient study revealed marked shifts in gut microbial community structure and function during the KD. Gradient diet experiments in mice confirmed the unique impact of KDs relative to HFDs with a reproducible depletion of bifidobacteria. In vitro and in vivo experiments showed that ketone bodies selectively inhibited bifidobacterial growth. Finally, mono-colonizations and human microbiome transplantations into germ-free mice revealed that the KD-associated gut microbiota reduces the levels of intestinal pro-inflammatory Th17 cells. Together, these results highlight the importance of trans-kingdom chemical dialogs for mediating the host response to dietary interventions.


Assuntos
Microbioma Gastrointestinal/imunologia , Microbioma Gastrointestinal/fisiologia , Intestinos/imunologia , Intestinos/microbiologia , Células Th17/imunologia , Células Th17/fisiologia , Adolescente , Adulto , Animais , Dieta Hiperlipídica/métodos , Dieta Cetogênica/métodos , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microbiota/imunologia , Microbiota/fisiologia , Pessoa de Meia-Idade , Células Th17/microbiologia , Adulto Jovem
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