RESUMO
The gut microbiota has been found to play an important role in the progression of metabolic dysfunction-associated steatohepatitis (MASH), but the mechanisms have not been established. Here, by developing a click-chemistry-based enrichment strategy, we identified several microbial-derived bile acids, including the previously uncharacterized 3-succinylated cholic acid (3-sucCA), which is negatively correlated with liver damage in patients with liver-tissue-biopsy-proven metabolic dysfunction-associated fatty liver disease (MAFLD). By screening human bacterial isolates, we identified Bacteroides uniformis strains as effective producers of 3-sucCA both in vitro and in vivo. By activity-based protein purification and identification, we identified an enzyme annotated as ß-lactamase in B. uniformis responsible for 3-sucCA biosynthesis. Furthermore, we found that 3-sucCA is a lumen-restricted metabolite and alleviates MASH by promoting the growth of Akkermansia muciniphila. Together, our data offer new insights into the gut microbiota-liver axis that may be leveraged to augment the management of MASH.
Assuntos
Akkermansia , Bacteroides , Ácidos e Sais Biliares , Microbioma Gastrointestinal , Hepatopatia Gordurosa não Alcoólica , Simbiose , Animais , Humanos , Masculino , Camundongos , Akkermansia/metabolismo , Bacteroides/metabolismo , beta-Lactamases/metabolismo , Ácidos e Sais Biliares/metabolismo , Vias Biossintéticas/genética , Fígado Gorduroso/metabolismo , Fígado/metabolismo , Camundongos Endogâmicos C57BL , Verrucomicrobia/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/microbiologiaRESUMO
The repertoire of modifications to bile acids and related steroidal lipids by host and microbial metabolism remains incompletely characterized. To address this knowledge gap, we created a reusable resource of tandem mass spectrometry (MS/MS) spectra by filtering 1.2 billion publicly available MS/MS spectra for bile-acid-selective ion patterns. Thousands of modifications are distributed throughout animal and human bodies as well as microbial cultures. We employed this MS/MS library to identify polyamine bile amidates, prevalent in carnivores. They are present in humans, and their levels alter with a diet change from a Mediterranean to a typical American diet. This work highlights the existence of many more bile acid modifications than previously recognized and the value of leveraging public large-scale untargeted metabolomics data to discover metabolites. The availability of a modification-centric bile acid MS/MS library will inform future studies investigating bile acid roles in health and disease.
Assuntos
Ácidos e Sais Biliares , Microbioma Gastrointestinal , Metabolômica , Espectrometria de Massas em Tandem , Animais , Humanos , Ácidos e Sais Biliares/química , Metabolômica/métodos , Poliaminas , Espectrometria de Massas em Tandem/métodos , Bases de Dados de Compostos QuímicosRESUMO
Hepatocytes, the major metabolic hub of the body, execute functions that are human-specific, altered in human disease, and currently thought to be regulated through endocrine and cell-autonomous mechanisms. Here, we show that key metabolic functions of human hepatocytes are controlled by non-parenchymal cells (NPCs) in their microenvironment. We developed mice bearing human hepatic tissue composed of human hepatocytes and NPCs, including human immune, endothelial, and stellate cells. Humanized livers reproduce human liver architecture, perform vital human-specific metabolic/homeostatic processes, and model human pathologies, including fibrosis and non-alcoholic fatty liver disease (NAFLD). Leveraging species mismatch and lipidomics, we demonstrate that human NPCs control metabolic functions of human hepatocytes in a paracrine manner. Mechanistically, we uncover a species-specific interaction whereby WNT2 secreted by sinusoidal endothelial cells controls cholesterol uptake and bile acid conjugation in hepatocytes through receptor FZD5. These results reveal the essential microenvironmental regulation of hepatic metabolism and its human-specific aspects.
Assuntos
Células Endoteliais , Fígado , Animais , Humanos , Camundongos , Células Endoteliais/metabolismo , Hepatócitos/metabolismo , Células de Kupffer/metabolismo , Fígado/citologia , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Fibrose/metabolismoRESUMO
Hundreds of microbiota genes are associated with host biology/disease. Unraveling the causal contribution of a microbiota gene to host biology remains difficult because many are encoded by nonmodel gut commensals and not genetically targetable. A general approach to identify their gene transfer methodology and build their gene manipulation tools would enable mechanistic dissections of their impact on host physiology. We developed a pipeline that identifies the gene transfer methods for multiple nonmodel microbes spanning five phyla, and we demonstrated the utility of their genetic tools by modulating microbiome-derived short-chain fatty acids and bile acids in vitro and in the host. In a proof-of-principle study, by deleting a commensal gene for bile acid synthesis in a complex microbiome, we discovered an intriguing role of this gene in regulating colon inflammation. This technology will enable genetically engineering the nonmodel gut microbiome and facilitate mechanistic dissection of microbiota-host interactions.
Assuntos
Microbioma Gastrointestinal/genética , Genes Bacterianos , Animais , Ácidos e Sais Biliares/metabolismo , Sistemas CRISPR-Cas/genética , Clostridium/genética , Colite/induzido quimicamente , Colite/microbiologia , Colite/patologia , Sulfato de Dextrana , Resistência Microbiana a Medicamentos/genética , Feminino , Regulação Bacteriana da Expressão Gênica , Técnicas de Transferência de Genes , Vida Livre de Germes , Inflamação/patologia , Intestinos/patologia , Masculino , Metaboloma/genética , Metagenômica , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutagênese Insercional/genética , Mutação/genética , RNA Ribossômico 16S/genética , Transcrição GênicaRESUMO
Live bacterial therapeutics (LBTs) could reverse diseases by engrafting in the gut and providing persistent beneficial functions in the host. However, attempts to functionally manipulate the gut microbiome of conventionally raised (CR) hosts have been unsuccessful because engineered microbial organisms (i.e., chassis) have difficulty in colonizing the hostile luminal environment. In this proof-of-concept study, we use native bacteria as chassis for transgene delivery to impact CR host physiology. Native Escherichia coli bacteria isolated from the stool cultures of CR mice were modified to express functional genes. The reintroduction of these strains induces perpetual engraftment in the intestine. In addition, engineered native E. coli can induce functional changes that affect physiology of and reverse pathology in CR hosts months after administration. Thus, using native bacteria as chassis to "knock in" specific functions allows mechanistic studies of specific microbial activities in the microbiome of CR hosts and enables LBT with curative intent.
Assuntos
Microbioma Gastrointestinal , Microbiota , Animais , Bactérias/genética , Escherichia coli/genética , Microbioma Gastrointestinal/fisiologia , Camundongos , TransgenesRESUMO
The microbiota shields the host against infections in a process known as colonization resistance. How infections themselves shape this fundamental process remains largely unknown. Here, we show that gut microbiota from previously infected hosts display enhanced resistance to infection. This long-term functional remodeling is associated with altered bile acid metabolism leading to the expansion of taxa that utilize the sulfonic acid taurine. Notably, supplying exogenous taurine alone is sufficient to induce this alteration in microbiota function and enhance resistance. Mechanistically, taurine potentiates the microbiota's production of sulfide, an inhibitor of cellular respiration, which is key to host invasion by numerous pathogens. As such, pharmaceutical sequestration of sulfide perturbs the microbiota's composition and promotes pathogen invasion. Together, this work reveals a process by which the host, triggered by infection, can deploy taurine as a nutrient to nourish and train the microbiota, promoting its resistance to subsequent infection.
Assuntos
Microbioma Gastrointestinal , Interações Hospedeiro-Patógeno , Animais , Infecções Bacterianas/imunologia , Infecções Bacterianas/microbiologia , Contagem de Colônia Microbiana , Microbioma Gastrointestinal/efeitos dos fármacos , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Imunidade , Camundongos Endogâmicos C57BL , Sulfetos/metabolismo , Taurina/farmacologiaRESUMO
The gut microbiome is the resident microbial community of the gastrointestinal tract. This community is highly diverse, but how microbial diversity confers resistance or susceptibility to intestinal pathogens is poorly understood. Using transplantation of human microbiomes into several animal models of infection, we show that key microbiome species shape the chemical environment of the gut through the activity of the enzyme bile salt hydrolase. The activity of this enzyme reduced colonization by the major human diarrheal pathogen Vibrio cholerae by degrading the bile salt taurocholate that activates the expression of virulence genes. The absence of these functions and species permits increased infection loads on a personal microbiome-specific basis. These findings suggest new targets for individualized preventative strategies of V. cholerae infection through modulating the structure and function of the gut microbiome.
Assuntos
Cólera/metabolismo , Suscetibilidade a Doenças/microbiologia , Microbioma Gastrointestinal/fisiologia , Adulto , Animais , Ácidos e Sais Biliares , Cólera/microbiologia , Modelos Animais de Doenças , Transplante de Microbiota Fecal/métodos , Feminino , Interações Hospedeiro-Patógeno/fisiologia , Humanos , Hidrolases/análise , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microbiota , Ácido Taurocólico/metabolismo , Vibrio cholerae/patogenicidade , Vibrio cholerae/fisiologia , VirulênciaRESUMO
Chikungunya virus (CHIKV), an emerging alphavirus, has infected millions of people. However, the factors modulating disease outcome remain poorly understood. Here, we show in germ-free mice or in oral antibiotic-treated conventionally housed mice with depleted intestinal microbiomes that greater CHIKV infection and spread occurs within 1 day of virus inoculation. Alteration of the microbiome alters TLR7-MyD88 signaling in plasmacytoid dendritic cells (pDCs) and blunts systemic production of type I interferon (IFN). Consequently, circulating monocytes express fewer IFN-stimulated genes and become permissive for CHIKV infection. Reconstitution with a single bacterial species, Clostridium scindens, or its derived metabolite, the secondary bile acid deoxycholic acid, can restore pDC- and MyD88-dependent type I IFN responses to restrict systemic CHIKV infection and transmission back to vector mosquitoes. Thus, symbiotic intestinal bacteria modulate antiviral immunity and levels of circulating alphaviruses within hours of infection through a bile acid-pDC-IFN signaling axis, which affects viremia, dissemination, and potentially transmission.
Assuntos
Ácidos e Sais Biliares/metabolismo , Febre de Chikungunya/patologia , Microbioma Gastrointestinal , Interferon Tipo I/metabolismo , Animais , Antibacterianos/farmacologia , Febre de Chikungunya/imunologia , Febre de Chikungunya/veterinária , Vírus Chikungunya/genética , Vírus Chikungunya/isolamento & purificação , Clostridiales/fisiologia , Células Dendríticas/citologia , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Transplante de Microbiota Fecal , Microbioma Gastrointestinal/efeitos dos fármacos , Masculino , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Monócitos/citologia , Monócitos/imunologia , Monócitos/metabolismo , Fator 88 de Diferenciação Mieloide/deficiência , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/metabolismo , RNA Viral/sangue , Fator de Transcrição STAT1/deficiência , Transdução de Sinais , Receptor 7 Toll-Like/metabolismoRESUMO
The gut microbiome has been implicated in multiple human chronic gastrointestinal (GI) disorders. Determining its mechanistic role in disease has been difficult due to apparent disconnects between animal and human studies and lack of an integrated multi-omics view of disease-specific physiological changes. We integrated longitudinal multi-omics data from the gut microbiome, metabolome, host epigenome, and transcriptome in the context of irritable bowel syndrome (IBS) host physiology. We identified IBS subtype-specific and symptom-related variation in microbial composition and function. A subset of identified changes in microbial metabolites correspond to host physiological mechanisms that are relevant to IBS. By integrating multiple data layers, we identified purine metabolism as a novel host-microbial metabolic pathway in IBS with translational potential. Our study highlights the importance of longitudinal sampling and integrating complementary multi-omics data to identify functional mechanisms that can serve as therapeutic targets in a comprehensive treatment strategy for chronic GI diseases. VIDEO ABSTRACT.
Assuntos
Microbioma Gastrointestinal/genética , Regulação da Expressão Gênica/genética , Síndrome do Intestino Irritável/metabolismo , Metaboloma , Purinas/metabolismo , Transcriptoma/genética , Animais , Ácidos e Sais Biliares/metabolismo , Biópsia , Butiratos/metabolismo , Cromatografia Líquida , Estudos Transversais , Epigenômica , Fezes/microbiologia , Feminino , Microbioma Gastrointestinal/fisiologia , Regulação da Expressão Gênica/fisiologia , Interações entre Hospedeiro e Microrganismos/genética , Humanos , Hipoxantina/metabolismo , Síndrome do Intestino Irritável/genética , Síndrome do Intestino Irritável/microbiologia , Estudos Longitudinais , Masculino , Metaboloma/fisiologia , Camundongos , Estudos Observacionais como Assunto , Estudos Prospectivos , Software , Espectrometria de Massas em Tandem , Transcriptoma/fisiologiaRESUMO
Emerging evidence indicates a central role for the microbiome in immunity. However, causal evidence in humans is sparse. Here, we administered broad-spectrum antibiotics to healthy adults prior and subsequent to seasonal influenza vaccination. Despite a 10,000-fold reduction in gut bacterial load and long-lasting diminution in bacterial diversity, antibody responses were not significantly affected. However, in a second trial of subjects with low pre-existing antibody titers, there was significant impairment in H1N1-specific neutralization and binding IgG1 and IgA responses. In addition, in both studies antibiotics treatment resulted in (1) enhanced inflammatory signatures (including AP-1/NR4A expression), observed previously in the elderly, and increased dendritic cell activation; (2) divergent metabolic trajectories, with a 1,000-fold reduction in serum secondary bile acids, which was highly correlated with AP-1/NR4A signaling and inflammasome activation. Multi-omics integration revealed significant associations between bacterial species and metabolic phenotypes, highlighting a key role for the microbiome in modulating human immunity.
Assuntos
Antibacterianos/farmacologia , Anticorpos Antivirais/imunologia , Microbioma Gastrointestinal/fisiologia , Imunidade/efeitos dos fármacos , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Adolescente , Adulto , Formação de Anticorpos , Feminino , Microbioma Gastrointestinal/efeitos dos fármacos , Voluntários Saudáveis , Humanos , Imunogenicidade da Vacina/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Masculino , Adulto JovemRESUMO
Dietary soluble fibers are fermented by gut bacteria into short-chain fatty acids (SCFA), which are considered broadly health-promoting. Accordingly, consumption of such fibers ameliorates metabolic syndrome. However, incorporating soluble fiber inulin, but not insoluble fiber, into a compositionally defined diet, induced icteric hepatocellular carcinoma (HCC). Such HCC was microbiota-dependent and observed in multiple strains of dysbiotic mice but not in germ-free nor antibiotics-treated mice. Furthermore, consumption of an inulin-enriched high-fat diet induced both dysbiosis and HCC in wild-type (WT) mice. Inulin-induced HCC progressed via early onset of cholestasis, hepatocyte death, followed by neutrophilic inflammation in liver. Pharmacologic inhibition of fermentation or depletion of fermenting bacteria markedly reduced intestinal SCFA and prevented HCC. Intervening with cholestyramine to prevent reabsorption of bile acids also conferred protection against such HCC. Thus, its benefits notwithstanding, enrichment of foods with fermentable fiber should be approached with great caution as it may increase risk of HCC.
Assuntos
Carcinoma Hepatocelular/etiologia , Colestase/complicações , Fibras na Dieta/metabolismo , Disbiose/complicações , Fermentação , Microbioma Gastrointestinal , Neoplasias Hepáticas/etiologia , Animais , Carcinoma Hepatocelular/microbiologia , Linhagem Celular Tumoral , Colestase/microbiologia , Dieta Hiperlipídica/efeitos adversos , Disbiose/microbiologia , Inulina/efeitos adversos , Neoplasias Hepáticas/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Hepatitis B virus (HBV) infection affects 240 million people worldwide. A liver-specific bile acid transporter named the sodium taurocholate cotransporting polypeptide (NTCP) has been identified as the cellular receptor for HBV and its satellite, the hepatitis D virus (HDV). NTCP likely acts as a major determinant for the liver tropism and species specificity of HBV and HDV at the entry level. NTCP-mediated HBV entry interferes with bile acid transport in cell cultures and has been linked with alterations in bile acid and cholesterol metabolism in vivo. The human liver carcinoma cell line HepG2, complemented with NTCP, now provides a valuable platform for studying the basic biology of the viruses and developing treatments for HBV infection. This review summarizes critical findings regarding NTCP's role as a viral receptor for HBV and HDV and discusses important questions that remain unanswered.
Assuntos
Vírus da Hepatite B/metabolismo , Receptores de Superfície Celular/metabolismo , Animais , Proteínas de Transporte/metabolismo , Vírus Delta da Hepatite/metabolismo , Humanos , Glicoproteínas de Membrana/metabolismo , Transportadores de Ânions Orgânicos Dependentes de Sódio/metabolismo , Simportadores/metabolismoRESUMO
Deregulated cell proliferation is an established feature of cancer, and altered tumor metabolism has witnessed renewed interest over the past decade, including the study of how cancer cells rewire metabolic pathways to renew energy sources and "building blocks" that sustain cell division. Microenvironmental oxygen, glucose, and glutamine are regarded as principal nutrients fueling tumor growth. However, hostile tumor microenvironments render O2/nutrient supplies chronically insufficient for increased proliferation rates, forcing cancer cells to develop strategies for opportunistic modes of nutrient acquisition. Recent work shows that cancer cells overcome this nutrient scarcity by scavenging other substrates, such as proteins and lipids, or utilizing adaptive metabolic pathways. As such, reprogramming lipid metabolism plays important roles in providing energy, macromolecules for membrane synthesis, and lipid-mediated signaling during cancer progression. In this review, we highlight more recently appreciated roles for lipids, particularly cholesterol and its derivatives, in cancer cell metabolism within intrinsically harsh tumor microenvironments.
Assuntos
Proliferação de Células , Colesterol/metabolismo , Metabolismo Energético , Neoplasias/metabolismo , Animais , Microbioma Gastrointestinal , Humanos , Neoplasias/imunologia , Neoplasias/microbiologia , Neoplasias/patologia , Obesidade/metabolismo , Obesidade/patologia , Transdução de Sinais , Evasão Tumoral , Hipóxia Tumoral , Microambiente TumoralRESUMO
Despite decades of fiercely competitive research and colossal financial investments, the majority of patients with advanced solid cancers cannot be treated with curative intent. To improve this situation, conceptually novel treatment approaches are urgently needed. Cancer is increasingly appreciated as a systemic disease and numerous organismal factors are functionally linked to neoplastic growth, e.g. systemic metabolic dysregulation, chronic inflammation, intestinal dysbiosis and disrupted circadian rhythms. It is tempting to hypothesize that interventions targeting these processes could be of significant account for cancer patients. One important driver of tumor-supporting systemic derangements is inordinate consumption of simple and highly processed carbohydrates. This dietary pattern is causally linked to hyperinsulinemia, insulin resistance, chronic inflammation and intestinal dysbiosis, begging the pertinent question whether the adoption of dietary carbohydrate restriction can be beneficial for patients with cancer. This review summarizes the published data on the role of dietary carbohydrate restriction in the pathogenesis of Hepatocellular Carcinoma (HCC), the most frequent type of primary liver cancer. In addition to outlining the functional interplay between diet, the intestinal microbiome and immunity, the review underscores the importance of bile acids as interconnectors between the intestinal microbiota and immune cells.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carboidratos da Dieta , Disbiose , InflamaçãoRESUMO
Bile acids are the end products of cholesterol catabolism. Hepatic bile acid synthesis accounts for a major fraction of daily cholesterol turnover in humans. Biliary secretion of bile acids generates bile flow and facilitates biliary secretion of lipids, endogenous metabolites and xenobiotics. In intestine, bile acids facilitate the digestion and absorption of dietary lipids and fat-soluble vitamins. Through activation of nuclear receptors and G protein-coupled receptors and interaction with gut microbiome, bile acids critically regulate host metabolism and innate and adaptive immunity, and are involved in the pathogenesis of cholestasis, metabolic dysfunction-associated steatotic liver disease (MASLD), alcohol-associated liver disease (ALD), type-2 diabetes, and inflammatory bowel diseases (IBD). Bile acids and their derivatives have been developed as potential therapeutic agents for treating chronic metabolic and inflammatory liver diseases and gastrointestinal disorders. Significance Statement Bile acids facilitate biliary cholesterol solubilization and dietary lipid absorption, regulate host metabolism and immunity, and modulate gut microbiome. Targeting bile acid metabolism and signaling hold promise for treating metabolic and inflammatory diseases.
RESUMO
Hepatocyte organoids (HOs) generated in vitro are powerful tools for liver regeneration. However, previously reported HOs have mostly been fetal in nature with low expression levels of metabolic genes characteristic of adult liver functions, hampering their application in studies of metabolic regulation and therapeutic testing for liver disorders. Here, we report development of novel culture conditions that combine optimized levels of triiodothyronine (T3) with the removal of growth factors to enable successful generation of mature hepatocyte organoids (MHOs) of both mouse and human origin with metabolic functions characteristic of adult livers. We show that the MHOs can be used to study various metabolic functions including bile and urea production, zonal metabolic gene expression, and metabolic alterations in both alcoholic liver disease and non-alcoholic fatty liver disease, as well as hepatocyte proliferation, injury and cell fate changes. Notably, MHOs derived from human fetal hepatocytes also show improved hepatitis B virus infection. Therefore, these MHOs provide a powerful in vitro model for studies of human liver physiology and diseases. The human MHOs are potentially also a robust research tool for therapeutic development.
Assuntos
Hepatócitos , Fígado , Organoides , Hepatócitos/metabolismo , Hepatócitos/citologia , Organoides/metabolismo , Organoides/citologia , Humanos , Animais , Camundongos , Fígado/metabolismo , Fígado/citologia , Camundongos Endogâmicos C57BL , Diferenciação CelularRESUMO
CD4+ T cells are tightly regulated by microbiota in the intestine, but whether intestinal T cells interface with host-derived metabolites is less clear. Here, we show that CD4+ T effector (Teff) cells upregulated the xenobiotic transporter, Mdr1, in the ileum to maintain homeostasis in the presence of bile acids. Whereas wild-type Teff cells upregulated Mdr1 in the ileum, those lacking Mdr1 displayed mucosal dysfunction and induced Crohn's disease-like ileitis following transfer into Rag1-/- hosts. Mdr1 mitigated oxidative stress and enforced homeostasis in Teff cells exposed to conjugated bile acids (CBAs), a class of liver-derived emulsifying agents that actively circulate through the ileal mucosa. Blocking ileal CBA reabsorption in transferred Rag1-/- mice restored Mdr1-deficient Teff cell homeostasis and attenuated ileitis. Further, a subset of ileal Crohn's disease patients displayed MDR1 loss of function. Together, these results suggest that coordinated interaction between mucosal Teff cells and CBAs in the ileum regulate intestinal immune homeostasis.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/imunologia , Ácidos e Sais Biliares/imunologia , Linfócitos T CD4-Positivos/imunologia , Doença de Crohn/imunologia , Ileíte/imunologia , Mucosa Intestinal/imunologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/deficiência , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Acridinas/farmacologia , Adulto , Animais , Ácidos e Sais Biliares/metabolismo , Ácidos e Sais Biliares/farmacologia , Transporte Biológico , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/patologia , Doença de Crohn/genética , Doença de Crohn/patologia , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/imunologia , Homeostase/imunologia , Humanos , Ileíte/genética , Ileíte/patologia , Íleo/imunologia , Íleo/patologia , Imunidade nas Mucosas , Mucosa Intestinal/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Pessoa de Meia-Idade , Estresse Oxidativo , Transdução de Sinais , Tetra-Hidroisoquinolinas/farmacologiaRESUMO
Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide, ranking fourth in frequency. The relationship between metabolic reprogramming and immune infiltration has been identified as having a crucial impact on HCC progression. However, a deeper understanding of the interplay between the immune system and metabolism in the HCC microenvironment is required. In this study, we used a proteomic dataset to identify three immune subtypes (IM1-IM3) in HCC, each of which has distinctive clinical, immune, and metabolic characteristics. Among these subtypes, IM3 was found to have the poorest prognosis, with the highest levels of immune infiltration and T-cell exhaustion. Furthermore, IM3 showed elevated glycolysis and reduced bile acid metabolism, which was strongly correlated with CD8 T cell exhaustion and regulatory T cell accumulation. Our study presents the proteomic immune stratification of HCC, revealing the possible link between immune cells and reprogramming of HCC glycolysis and bile acid metabolism, which may be a viable therapeutic strategy to improve HCC immunotherapy.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Proteoma , Proteômica , Microambiente Tumoral , Ácidos e Sais BiliaresRESUMO
Intestinal bile acids play an essential role in the Clostridioides difficile lifecycle having been shown in vitro to modulate various aspects of pathogenesis, including spore germination, vegetative growth, and more recently the action of the primary virulence determinant, TcdB. Here, we investigated whether physiological levels of the total pool of intestinal bile acids in mice and humans protect against TcdB action. Small molecules extracted from the lumenal contents of the small intestine, cecum, colon, and feces were found to inhibit TcdB in accordance with the differential amounts of total bile acids in each compartment. Extracts from antibiotic-treated and germ-free mice, despite harboring dramatically altered bile acid profiles, unexpectedly also prevented TcdB-induced cell rounding to similar extents. We show that protection, however, is surmountable and can be overcome at higher doses of TcdB-typical to those seen during severe C. difficile infection-suggesting that the protective properties of intestinal bile acids are operant primarily under low to moderate toxin levels. Taken together, these findings demonstrate a role for intestinal bile acids in attenuating virulence, provide insights into asymptomatic carriage of toxigenic C. difficile, and inform strategies to manipulate bile acid levels for therapeutic benefit.
Assuntos
Toxinas Bacterianas , Clostridioides difficile , Infecções por Clostridium , Humanos , Camundongos , Animais , Ácidos e Sais Biliares , Infecções por Clostridium/patologia , Intestinos/patologia , Proteínas de BactériasRESUMO
Many animal and plant species synthesize toxic compounds as deterrent; thus, detection of these compounds is of vital importance to avoid their ingestion. Often, such compounds are recognized by taste 2 receptors that mediate bitter taste in humans. Until now, bitter taste receptors have only been found in bony vertebrates, where they occur as a large family already in coelacanth, a "living fossil" and the earliest-diverging extant lobe-finned fish. Here, we have revisited the evolutionary origin of taste 2 receptors (T2Rs) making use of a multitude of recently available cartilaginous fish genomes. We have identified a singular T2R in 12 cartilaginous fish species (9 sharks, 1 sawfish, and 2 skates), which represents a sister clade to all bony fish T2Rs. We have examined its ligands for two shark species, a catshark and a bamboo shark. The ligand repertoire of bamboo shark represents a subset of that of the catshark, with roughly similar thresholds. Amarogentin, one of the most bitter natural substances for humans, also elicited the highest signal amplitudes with both shark receptors. Other subsets of ligands are shared with basal bony fish T2Rs indicating an astonishing degree of functional conservation over nearly 500 mya of separate evolution. Both shark receptors respond to endogenous steroids as well as xenobiotic compounds, whereas separate receptors exist for xenobiotics both in early- and late-derived bony vertebrates (coelacanth, zebrafish, and human), consistent with the shark T2R reflecting the original ligand repertoire of the ancestral bitter taste receptor at the evolutionary origin of this family.