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BACKGROUND AND AIMS: Bile acids (BA) are vital regulators of metabolism. BAs are AQ6 secreted in the small intestine, reabsorbed, and transported back to the liver, where they can modulate metabolic functions. There is a paucity of data regarding the portal BA composition in humans. This study aimed to address this knowledge gap by investigating portal BA composition and the relation with peripheral and fecal BA dynamics in conjunction with the gut microbiome. APPROACH AND RESULTS: Thirty-three individuals from the BARIA cohort were included. Portal plasma, peripheral plasma, and feces were collected. BA and C4 levels were measured employing mass spectrometry. FGF19 was measured using ELISA. Gut microbiota composition was determined through metagenomics analysis on stool samples. Considerable diversity in the portal BA composition was observed. The majority (n = 26) of individuals had a 9-fold higher portal than peripheral BA concentration. In contrast, 8 individuals showed lower portal BA concentration compared with peripheral and had higher levels of unconjugated and secondary BA in this compartment, suggesting more distal origin. The altered portal BA profile was associated with altered gut microbiota composition. In particular, taxa within Bacteroides were reduced in abundance in the feces of these individuals. CONCLUSIONS: Characterization of the portal BA composition in relation to peripheral and fecal BA increased insight into the dynamics of BA metabolism in individuals with obesity. Peripheral BA composition was much more diverse due to microbial metabolism. About 24% of the portal samples was surprisingly low in total BA; the underlying mechanism requires further exploration.
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OBJECTIVE: Dietary fibres are essential for maintaining microbial diversity and the gut microbiota can modulate host physiology by metabolising the fibres. Here, we investigated whether the soluble dietary fibre oligofructose improves host metabolism by modulating bacterial transformation of secondary bile acids in mice fed western-style diet. DESIGN: To assess the impact of dietary fibre supplementation on bile acid transformation by gut bacteria, we fed conventional wild-type and TGR5 knockout mice western-style diet enriched or not with cellulose or oligofructose. In addition, we used germ-free mice and in vitro cultures to evaluate the activity of bacteria to transform bile acids in the caecal content of mice fed with western-style diet enriched with oligofructose. Finally, we treated wild-type and TGR5 knockout mice orally with hyodeoxycholic acid to assess its antidiabetic effects. RESULTS: We show that oligofructose sustains the production of 6α-hydroxylated bile acids from primary bile acids by gut bacteria when fed western-style diet. Mechanistically, we demonstrated that the effects of oligofructose on 6α-hydroxylated bile acids were microbiota dependent and specifically required functional TGR5 signalling to reduce body weight gain and improve glucose metabolism. Furthermore, we show that the 6α-hydroxylated bile acid hyodeoxycholic acid stimulates TGR5 signalling, in vitro and in vivo, and increases GLP-1R activity to improve host glucose metabolism. CONCLUSION: Modulation of the gut microbiota with oligofructose enriches bacteria involved in 6α-hydroxylated bile acid production and leads to TGR5-GLP1R axis activation to improve body weight and metabolism under western-style diet feeding in mice.
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Ácidos y Sales Biliares , Dieta Occidental , Fibras de la Dieta , Suplementos Dietéticos , Microbioma Gastrointestinal , Glucosa , Receptores Acoplados a Proteínas G , Animales , Ratones , Ácidos y Sales Biliares/metabolismo , Peso Corporal , Glucosa/metabolismo , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Fibras de la Dieta/administración & dosificaciónRESUMEN
Mice with deletion of Cyp2c70 have a human-like bile acid composition, display age- and sex-dependent signs of hepatobiliary disease and can be used as a model to study interactions between bile acids and the gut microbiota in cholestatic liver disease. In the present study, we rederived Cyp2c70-/- mice as germ-free (GF) and colonized them with a human or a mouse microbiota to investigate whether the presence of a microbiota can be protective in cholangiopathic liver disease associated with Cyp2c70-deficiency. GF Cyp2c70-/- mice showed reduced neonatal survival, liver fibrosis, and distinct cholangiocyte proliferation. Colonization of germ-free breeding pairs with a human or a mouse microbiota normalized neonatal survival of the offspring, and particularly colonization with mouse microbiota from a conventionally raised mouse improved the liver phenotype at 6-10 weeks of age. The improved liver phenotype in conventionalized (CD) Cyp2c70-/- mice was associated with increased levels of tauro-ursodeoxycholic acid (TUDCA) and UDCA, resulting in a more hydrophilic bile acid profile compared with GF and humanized Cyp2c70-/- mice. The hydrophobicity index of biliary bile acids of CD Cyp2c70-/- mice was associated with changes in gut microbiota, liver weight, liver transaminases, and liver fibrosis. Hence, our results indicate that neonatal survival of Cyp2c70-/- mice seems to depend on the establishment of a gut microbiota at birth, and the improved liver phenotype in CD Cyp2c70-/- mice may be mediated by a larger proportion of TUDCA/UDCA in the circulating bile acid pool and/or by the presence of specific bacteria.
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Ácidos y Sales Biliares , Microbioma Gastrointestinal , Hepatopatías , Animales , Femenino , Masculino , Ratones , Animales Recién Nacidos , Ácidos y Sales Biliares/metabolismo , Hepatopatías/metabolismo , Hepatopatías/mortalidad , Análisis de Supervivencia , Ratones NoqueadosRESUMEN
Intrahepatic cholestasis of pregnancy (ICP) is characterized by elevated maternal circulating bile acid levels and associated dyslipidemia. ICP leads to accumulation of bile acids in the fetal compartment, and the elevated bile acid concentrations are associated with an increased risk of adverse fetal outcomes. The farnesoid X receptor agonist obeticholic acid (OCA) is efficient in the treatment of cholestatic conditions such as primary biliary cholangitis. We hypothesized that OCA administration during hypercholanemic pregnancy will improve maternal and fetal bile acid and lipid profiles. Female C57BL/6J mice were fed either a normal chow diet, a 0.5% cholic acid (CA)-supplemented diet, a 0.03% OCA-supplemented diet, or a 0.5% CA + 0.03% OCA-supplemented diet for 1 wk before mating and throughout pregnancy until euthanization on day 18. The effects of CA and OCA feeding on maternal and fetal morphometry, bile acid and lipid levels, and cecal microbiota were investigated. OCA administration during gestation did not alter the maternal or fetal body weight or organ morphometry. OCA treatment during hypercholanemic pregnancy reduced bile acid levels in the fetal compartment. However, fetal dyslipidemia was not reversed, and OCA did not impact maternal bile acid levels or dyslipidemia. In conclusion, OCA administration during gestation had no apparent detrimental impact on maternal or fetal morphometry and improved fetal hypercholanemia. Because high serum bile acid concentrations in ICP are associated with increased rates of adverse fetal outcomes, further investigations into the potential use of OCA during cholestatic gestation are warranted.NEW & NOTEWORTHY We used a mouse model of gestational hypercholanemia to investigate the use of obeticholic acid (OCA), a potent FXR agonist, as a treatment for the hypercholanemia of intrahepatic cholestasis of pregnancy (ICP). The results demonstrate that OCA can improve the fetal bile acid profile. This is relevant not only to women with ICP but also for women who become pregnant while receiving OCA treatment for other conditions such as primary biliary cholangitis and nonalcoholic steatohepatitis.
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Ácidos y Sales Biliares/sangre , Ácido Quenodesoxicólico/análogos & derivados , Colestasis Intrahepática/tratamiento farmacológico , Complicaciones del Embarazo/tratamiento farmacológico , Animales , Ácidos y Sales Biliares/metabolismo , Ciego , Ácido Quenodesoxicólico/farmacología , Colesterol 7-alfa-Hidroxilasa/genética , Colesterol 7-alfa-Hidroxilasa/metabolismo , Dislipidemias/tratamiento farmacológico , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/metabolismo , Ratones , Ratones Endogámicos C57BL , Embarazo , ARN Ribosómico 16S , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismoRESUMEN
Pregnancy is associated with progressive hypercholanemia, hypercholesterolemia, and hypertriglyceridemia, which can result in metabolic disease in susceptible women. Gut signals modify hepatic homeostatic pathways, linking intestinal content to metabolic activity. We sought to identify whether enteric endocrine signals contribute to raised serum bile acids observed in human and murine pregnancies, by measuring fibroblast growth factor (FGF) 19/15 protein and mRNA levels, and 7α-hydroxy-4-cholesten-3-one. Terminal ileal farnesoid X receptor (FXR)-mediated gene expression and apical sodium bile acid transporter (ASBT) protein concentration were measured by qPCR and western blotting. Shotgun whole-genome sequencing and ultra-performance liquid chromatography tandem mass spectrometry were used to determine the cecal microbiome and metabonome. Targeted and untargeted pathway analyses were performed to predict the systemic effects of the altered metagenome and metabolite profiles. Dietary CA supplementation was used to determine whether the observed alterations could be overcome by intestinal bile acids functioning as FXR agonists. Human and murine pregnancy were associated with reduced intestinal FXR signaling, with lower FGF19/15 and resultant increased hepatic bile acid synthesis. Terminal ileal ASBT protein was reduced in murine pregnancy. Cecal bile acid conjugation was reduced in pregnancy because of elevated bile salt hydrolase-producing Bacteroidetes. CA supplementation induced intestinal FXR signaling, which was not abrogated by pregnancy, with strikingly similar changes to the microbiota and metabonome as identified in pregnancy. Conclusion: The altered intestinal microbiota of pregnancy enhance bile acid deconjugation, reducing ileal bile acid uptake and lowering FXR induction in enterocytes. This exacerbates the effects mediated by reduced bile acid uptake transporters in pregnancy. Thus, in pregnant women and mice, there is reduced FGF19/15-mediated hepatic repression of hepatic bile acid synthesis, resulting in hypercholanemia.
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Ácidos Cólicos/sangre , Microbioma Gastrointestinal , Reabsorción Intestinal , Embarazo/sangre , Receptores Citoplasmáticos y Nucleares/metabolismo , Amidohidrolasas/genética , Animales , Bacteroides/aislamiento & purificación , Ciego/efectos de los fármacos , Ciego/microbiología , Ácidos Cólicos/farmacología , Enterocitos/efectos de los fármacos , Femenino , Humanos , Ratones Endogámicos C57BL , Receptores Citoplasmáticos y Nucleares/agonistasRESUMEN
BACKGROUND: Bile acids (BAs) regulate hepatic lipid metabolism and inflammation. Bile salt export pump (BSEP) KO mice are metabolically preconditioned with a hydrophilic BA composition protecting them from cholestasis. We hypothesize that changes in hepatic BA profile and subsequent changes in BA signalling may critically determine the susceptibility to steatohepatitis. METHODS: Wild-type (WT) and BSEP KO mice were challenged with methionine choline-deficient (MCD) diet to induce steatohepatitis. Serum biochemistry, lipid profiling as well as intestinal lipid absorption were assessed. Markers of inflammation, fibrosis, lipid and BA metabolism were analysed. Hepatic and faecal BA profile as well as serum levels of the BA synthesis intermediate 7-hydroxy-4-cholesten-3-one (C4) were also investigated. RESULTS: Bile salt export pump KO MCD-fed mice developed less steatosis but more inflammation than WT mice. Intestinal neutral lipid levels were reduced in BSEP KO mice at baseline and under MCD conditions. Faecal non-esterified fatty acid concentrations at baseline and under MCD diet were markedly elevated in BSEP KO compared to WT mice. Serum liver enzymes and hepatic expression of inflammatory markers were increased in MCD-fed BSEP KO animals. PPARα protein levels were reduced in BSEP KO mice. Accordingly, PPARα downstream targets Fabp1 and Fatp5 were repressed, while NFκB subunits were increased in MCD-fed BSEP KO mice. Farnesoid X receptor (FXR) protein levels were reduced in MCD-fed BSEP KO vs WT mice. Hepatic BA profile revealed elevated levels of TßMCA, exerting FXR antagonistic action, while concentrations of TCA (FXR agonistic function) were reduced. CONCLUSION: Presence of hydroxylated BAs result in increased faecal FA excretion and reduced hepatic lipid accumulation. This aggravates development of MCD diet-induced hepatitis potentially by decreasing FXR and PPARα signalling.
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Hígado Graso , Metionina , Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP , Animales , Ácidos y Sales Biliares , Colina , Dieta , Proteínas de Unión a Ácidos Grasos , Inflamación , Hígado , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
OBJECTIVE: There is a striking association between human cholestatic liver disease (CLD) and inflammatory bowel disease. However, the functional implications for intestinal microbiota and inflammasome-mediated innate immune response in CLD remain elusive. Here we investigated the functional role of gut-liver crosstalk for CLD in the murine Mdr2 knockout (Mdr2-/-) model resembling human primary sclerosing cholangitis (PSC). DESIGN: Male Mdr2-/-, Mdr2-/- crossed with hepatocyte-specific deletion of caspase-8 (Mdr2-/- /Casp8∆hepa) and wild-type (WT) control mice were housed for 8 or 52 weeks, respectively, to characterise the impact of Mdr2 deletion on liver and gut including bile acid and microbiota profiling. To block caspase activation, a pan-caspase inhibitor (IDN-7314) was administered. Finally, the functional role of Mdr2-/- -associated intestinal dysbiosis was studied by microbiota transfer experiments. RESULTS: Mdr2-/- mice displayed an unfavourable intestinal microbiota signature and pronounced NLRP3 inflammasome activation within the gut-liver axis. Intestinal dysbiosis in Mdr2-/- mice prompted intestinal barrier dysfunction and increased bacterial translocation amplifying the hepatic NLRP3-mediated innate immune response. Transfer of Mdr2-/- microbiota into healthy WT control mice induced significant liver injury in recipient mice, highlighting the causal role of intestinal dysbiosis for disease progression. Strikingly, IDN-7314 dampened inflammasome activation, ameliorated liver injury, reversed serum bile acid profile and cholestasis-associated microbiota signature. CONCLUSIONS: MDR2-associated cholestasis triggers intestinal dysbiosis. In turn, translocation of endotoxin into the portal vein and subsequent NLRP3 inflammasome activation contribute to higher liver injury. This process does not essentially depend on caspase-8 in hepatocytes, but can be blocked by IDN-7314.
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Proteína con Dominio Pirina 3 de la Familia NLR/inmunología , Subfamilia B de Transportador de Casetes de Unión a ATP/genética , Animales , Conductos Biliares , Caspasa 8/genética , Inhibidores de Caspasas/farmacología , Colangitis Esclerosante/metabolismo , Progresión de la Enfermedad , Disbiosis , Microbioma Gastrointestinal/fisiología , Humanos , Inmunidad Innata/efectos de los fármacos , Inmunidad Innata/inmunología , Hígado/inmunología , Ratones , Ratones Noqueados , Miembro 4 de la Subfamilia B de Casete de Unión a ATPRESUMEN
Metabolism alters markedly with advancing gestation, characterized by progressive insulin resistance, dyslipidemia, and raised serum bile acids. The nuclear receptor farnesoid X receptor (FXR) has an integral role in bile acid homeostasis and modulates glucose and lipid metabolism. FXR is known to be functionally suppressed in pregnancy. The FXR agonist, obeticholic acid (OCA), improves insulin sensitivity in patients with type 2 diabetes with nonalcoholic fatty liver disease. We therefore hypothesized that OCA treatment during pregnancy could improve disease severity in a mouse model of gestational diabetes mellitus (GDM). C57BL/6J mice were fed a high-fat diet (HFD; 60% kcal from fat) for 4 wk before and throughout pregnancy to induce GDM. The impact of the diet supplemented with 0.03% OCA throughout pregnancy was studied. Pregnant HFD-fed mice displayed insulin resistance and dyslipidemia. OCA significantly reduced plasma cholesterol concentrations in nonpregnant and pregnant HFD-fed mice (by 22.4%, P < 0.05 and 36.4%, P < 0.001, respectively) and reduced the impact of pregnancy on insulin resistance but did not change glucose tolerance. In nonpregnant HFD-fed mice, OCA ameliorated weight gain, reduced mRNA expression of inflammatory markers in white adipose tissue, and reduced plasma glucagon-like peptide 1 concentrations (by 62.7%, P < 0.01). However, these effects were not evident in pregnant mice. OCA administration can normalize plasma cholesterol levels in a mouse model of GDM. However, the absence of several of the effects of OCA in pregnant mice indicates that the agonistic action of OCA is not sufficient to overcome many metabolic consequences of the pregnancy-associated reduction in FXR activity.
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Glucemia/efectos de los fármacos , Ácido Quenodesoxicólico/análogos & derivados , Diabetes Gestacional/tratamiento farmacológico , Dislipidemias/tratamiento farmacológico , Animales , Glucemia/metabolismo , Ácido Quenodesoxicólico/uso terapéutico , Diabetes Gestacional/metabolismo , Diabetes Gestacional/patología , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Dislipidemias/complicaciones , Dislipidemias/metabolismo , Femenino , Intolerancia a la Glucosa/etiología , Intolerancia a la Glucosa/metabolismo , Intolerancia a la Glucosa/patología , Resistencia a la Insulina , Metabolismo de los Lípidos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C57BL , Embarazo , Complicaciones del Embarazo/tratamiento farmacológico , Complicaciones del Embarazo/metabolismoRESUMEN
BACKGROUND & AIMS: The nuclear farnesoid X receptor (FXR) agonist obeticholic acid (OCA) has been developed for the treatment of liver diseases. We aimed to determine whether OCA treatment increases the risk of gallstone formation. METHODS: Twenty patients awaiting laparoscopic cholecystectomy were randomized to treatment with OCA (25â¯mg/day) or placebo for 3â¯weeks until the day before surgery. Serum bile acids (BAs), the BA synthesis marker C4 (7α-hydroxy-4-cholesten-3-one), and fibroblast growth factor 19 (FGF19) were measured before and after treatment. During surgery, biopsies from the liver and the whole bile-filled gallbladder were collected for analyses of gene expression, biliary lipids and FGF19. RESULTS: In serum, OCA increased FGF19 (from 95.0⯱â¯8.5 to 234.4⯱â¯35.6â¯ng/L) and decreased C4 (from 31.4⯱â¯22.8 to 2.8⯱â¯4.0â¯nmol/L) and endogenous BAs (from 1,312.2⯱â¯236.2 to 517.7⯱â¯178.9â¯nmol/L; all p <0.05). At surgery, BAs in gallbladder bile were lower in patients that received OCA than in controls (OCA, 77.9⯱â¯53.6â¯mmol/L; placebo, 196.4⯱â¯99.3â¯mmol/L; p <0.01), resulting in a higher cholesterol saturation index (OCA, 2.8⯱â¯1.1; placebo, 1.8⯱â¯0.8; p <0.05). In addition, hydrophobic OCA conjugates accounted for 13.6⯱â¯5.0% of gallbladder BAs after OCA treatment, resulting in a higher hydrophobicity index (OCA, 0.43⯱â¯0.09; placebo, 0.34⯱â¯0.07, p <0.05). Gallbladder FGF19 levels were 3-fold higher in OCA patients than in controls (OCA, 40.3⯱â¯16.5â¯ng/L; placebo, 13.5⯱â¯13.1â¯ng/ml; p <0.005). Gene expression analysis indicated that FGF19 mainly originated from the gallbladder epithelium. CONCLUSIONS: Our results show for the first time an enrichment of FGF19 in human bile after OCA treatment. In accordance with its murine homolog FGF15, FGF19 might trigger relaxation and filling of the gallbladder which, in combination with increased cholesterol saturation and BA hydrophobicity, would enhance the risk of gallstone development. LAY SUMMARY: Obeticholic acid increased human gallbladder cholesterol saturation and bile acid hydrophobicity, both decreasing cholesterol solubility in bile. Together with increased hepatobiliary levels of fibroblast growth factor 19, our findings suggest that pharmacological activation of the farnesoid X receptor increases the risk of gallstone formation. Clinical trial number: NCT01625026.
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Ácido Quenodesoxicólico/análogos & derivados , Cálculos Biliares/inducido químicamente , Cálculos Biliares/cirugía , Hepatopatías/tratamiento farmacológico , Receptores Citoplasmáticos y Nucleares/agonistas , Adulto , Ácidos y Sales Biliares/sangre , Ácidos y Sales Biliares/genética , Biopsia , Proteínas Portadoras/genética , Ácido Quenodesoxicólico/efectos adversos , Ácido Quenodesoxicólico/farmacología , Colestenonas/sangre , Método Doble Ciego , Femenino , Factores de Crecimiento de Fibroblastos/sangre , Vesícula Biliar/patología , Vesícula Biliar/cirugía , Cálculos Biliares/sangre , Expresión Génica , Humanos , Hígado/patología , Hepatopatías/sangre , Masculino , Persona de Mediana Edad , Resultado del TratamientoRESUMEN
BACKGROUND AND AIMS: Interruption of the enterohepatic circulation of bile acids (BAs) may protect against BA-mediated cholestatic liver and bile duct injury. BA sequestrants are established to treat cholestatic pruritus, but their impact on the underlying cholestasis is still unclear. We aimed to explore the therapeutic effects and mechanisms of the BA sequestrant colesevelam in a mouse model of sclerosing cholangitis. METHODS: Mdr2-/- mice received colesevelam for 8 weeks. Gene expression profiles of BA homeostasis, inflammation and fibrosis were explored in liver, intestine and colon. Hepatic and faecal BA profiles and gut microbiome were analysed. Glucagon-like peptide 1 (GLP-1) levels in portal blood were measured by ELISA. Furthermore, Mdr2-/- mice as well as wild-type 3,5-diethoxy-carbonyl-1,4-dihydrocollidine-fed mice were treated with GLP-1-receptor agonist exendin-4 for 2 weeks prior to analysis. RESULTS: Colesevelam reduced serum liver enzymes, BAs and expression of proinflammatory and profibrogenic markers. Faecal BA profiling revealed increased levels of secondary BAs after resin treatment, while hepatic and biliary BA composition showed a shift towards more hydrophilic BAs. Colonic GLP-1 secretion, portal venous GLP-1 levels and intestinal messenger RNA expression of gut hormone Proglucagon were increased, while ileal Fgf15 expression was abolished by colesevelam. Exendin-4 treatment increased bile duct mass without promoting a reactive cholangiocyte phenotype in mouse models of sclerosing cholangitis. Microbiota analysis showed an increase of the phylum δ-Proteobacteria after colesevelam treatment and a shift within the phyla Firmicutes from Clostridiales to Lactobacillus. CONCLUSION: Colesevelam increases faecal BA excretion and enhances BA conversion towards secondary BAs, thereby stimulating secretion of GLP-1 from enteroendocrine L-cells and attenuates liver and bile duct injury in Mdr2-/- mice.
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Anticolesterolemiantes/uso terapéutico , Conductos Biliares/efectos de los fármacos , Colangitis Esclerosante/tratamiento farmacológico , Clorhidrato de Colesevelam/uso terapéutico , Hígado/efectos de los fármacos , Animales , Colestasis/tratamiento farmacológico , Modelos Animales de Enfermedad , Péptido 1 Similar al Glucagón/efectos de los fármacos , Homeostasis/efectos de los fármacos , Ratones , Ratones Noqueados , Resultado del TratamientoRESUMEN
The gut microbiota influences the development and progression of metabolic diseases partly by metabolism of bile acids (BAs) and modified signaling through the farnesoid X receptor (FXR). In this study, we aimed to determine how the human gut microbiota metabolizes murine BAs and affects FXR signaling in colonized mice. We colonized germ-free mice with cecal content from a mouse donor or feces from a human donor and euthanized the mice after short-term (2 weeks) or long-term (15 weeks) colonization. We analyzed the gut microbiota and BA composition and expression of FXR target genes in ileum and liver. We found that cecal microbiota composition differed between mice colonized with mouse and human microbiota and was stable over time. Human and mouse microbiota reduced total BA levels similarly, but the humanized mice produced less secondary BAs. The human microbiota was able to reduce the levels of tauro-ß-muricholic acid and induce expression of FXR target genes Fgf15 and Shp in ileum after long-term colonization. We show that a human microbiota can change BA composition and induce FXR signaling in colonized mice, but the levels of secondary BAs produced are lower than in mice colonized with a mouse microbiota.
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Factores de Crecimiento de Fibroblastos/metabolismo , Microbioma Gastrointestinal/genética , Enfermedades Metabólicas/genética , Proteínas del Tejido Nervioso/genética , Proteínas de Unión al ARN/metabolismo , Animales , Ácidos y Sales Biliares/metabolismo , Heces/microbiología , Factores de Crecimiento de Fibroblastos/genética , Humanos , Íleon/metabolismo , Íleon/microbiología , Mucosa Intestinal/metabolismo , Intestinos/microbiología , Hígado/metabolismo , Hígado/microbiología , Enfermedades Metabólicas/metabolismo , Enfermedades Metabólicas/microbiología , Enfermedades Metabólicas/patología , Ratones , Proteínas del Tejido Nervioso/metabolismo , Proteínas de Unión al ARN/agonistas , Proteínas de Unión al ARN/antagonistas & inhibidores , Proteínas de Unión al ARN/genética , Ácido Taurocólico/análogos & derivados , Ácido Taurocólico/metabolismoRESUMEN
BACKGROUND & AIMS: Cholestasis is characterized by intrahepatic accumulation of potentially cytotoxic bile acids (BAs) subsequently leading to liver injury with disruption of hepatocellular integrity, inflammation, fibrosis and ultimately liver cirrhosis. Bile salt export pump (BSEP/ABCB11) is the main canalicular BA transporter and therefore the rate limiting step for hepatobiliary BA excretion. In this study we aimed to investigate the role of BSEP/ABCB11 in the development of acquired cholestatic liver and bile duct injury. METHODS: Wild-type (WT) and BSEP knockout (BSEP-/-) mice were subjected to common bile duct ligation (CBDL) or 3.5-diethoxycarbonyl-1.4-dihydrocollidine (DDC) feeding as models for cholestasis with biliary obstruction and bile duct injury. mRNA expression profile, serum biochemistry, liver histology, immunohistochemistry, hepatic hydroxyproline levels and BA composition as well as biliary pressure were assessed. RESULTS: BSEP-/- mice were protected against acquired cholestatic liver injury induced by 7days of CBDL or 4weeks of DDC feeding, as reflected by unchanged serum levels of liver transaminases, alkaline phosphatase and BAs. Notably, BSEP-/- mice were also protected from cholestasis-induced hepatic inflammation and biliary fibrosis. In line with induced BA detoxification/hydroxylation pathways in BSEP-/- mice, polyhydroxylated BAs were increased 4-fold after CBDL and 6-fold after DDC feeding in comparison with cholestatic WT mice. Finally, following CBDL, biliary pressure in WT mice increased up to 47mmH2O but remained below 11mmH2O in BSEP-/- mice. CONCLUSION: Metabolic preconditioning with subsequent changes in BA metabolism favors detoxification of potentially toxic BAs and thereby protects BSEP-/- mice from cholestatic liver and bile duct injury. LAY SUMMARY: Reduced hepatobiliary bile acid transport due to loss of BSEP function leads to increased hydroxylation of bile acids in the liver. Metabolic preconditioning with a hydrophilic bile pool protects the BSEP-/- mice from acquired cholestatic liver disease.
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Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP/metabolismo , Ácidos y Sales Biliares/metabolismo , Conductos Biliares , Colestasis Intrahepática/metabolismo , Hepatocitos/metabolismo , Ligadura/métodos , Oclusión Terapéutica/métodos , Animales , Canalículos Biliares , Conductos Biliares/fisiopatología , Conductos Biliares/cirugía , Colestasis Intrahepática/prevención & control , RatonesRESUMEN
BACKGROUND & AIMS: Severe cholestasis may cause cholemic nephropathy that can be modeled in common bile duct ligated (CBDL) mice. We aimed to explore the therapeutic efficacy and mechanisms of norursodeoxycholic acid (norUDCA) in cholemic nephropathy. METHODS: In 8-week CBDL mice fed with norUDCA (prior or post CBDL) or chow we evaluated serum urea levels, urine cytology and urinary neutrophil gelatinase associated lipocalin (uNGAL), kidney and liver tissue quantification of fibrosis by hydroxyproline content and gene chip expression looking at key genes of inflammation and fibrosis. Moreover, we comprehensively analysed bile acid profiles in liver, kidney, serum and urine samples. RESULTS: NorUDCA-fed CBDL mice had significantly lower serum urea and uNGAL levels and less severe cholemic nephropathy as demonstrated by normal urine cytology, significantly reduced tubulointerstitial nephritis, and renal fibrosis as compared to controls. NorUDCA underwent extensive metabolism to produce even more hydrophilic compounds that were significantly enriched in kidneys. CONCLUSION: NorUDCA ameliorates cholemic nephropathy due to the formation of highly hydrophilic metabolites enriched in kidney. Consequently, norUDCA may represent a medical treatment for cholemic nephropathy. LAY SUMMARY: The term cholemic nephropathy describes renal dysfunction together with characteristic morphological alterations of the kidney in obstructive cholestasis that can be mimicked by ligation of the common bile duct in mice. Feeding the hydrophilic bile acid norUDCA to bile duct ligated mice leads to a significant amelioration of the renal phenotype due to the formation of highly hydrophilic metabolites enriched in the kidney and may therefore represent a medical treatment for cholemic nephropathy.
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Colestasis/complicaciones , Enfermedades Renales/tratamiento farmacológico , Ácido Ursodesoxicólico/análogos & derivados , Animales , Ácidos y Sales Biliares/orina , Modelos Animales de Enfermedad , Fibrosis , Riñón/efectos de los fármacos , Riñón/metabolismo , Riñón/patología , Ligadura , Lipocalina 2/sangre , Masculino , Ratones , Ratones Endogámicos C57BL , Nefritis Intersticial/tratamiento farmacológico , Ácido Ursodesoxicólico/metabolismo , Ácido Ursodesoxicólico/uso terapéuticoRESUMEN
BACKGROUND: The gut microbiota has a substantial impact on health and disease. The human gut microbiota influences the development and progression of metabolic diseases; however, the underlying mechanisms are not fully understood. The nuclear farnesoid X receptor (FXR), which regulates bile acid homeostasis and glucose and lipid metabolism, is activated by primary human and murine bile acids, chenodeoxycholic acid and cholic acid, while rodent specific primary bile acids tauromuricholic acids antagonise FXR activation. The gut microbiota deconjugates and subsequently metabolises primary bile acids into secondary bile acids in the gut and thereby changes FXR activation and signalling. Key Message: Mouse models have been used to study the crosstalk between bile acids and the gut microbiota, but the substantial differences in bile acid composition between humans and mice need to be considered when interpreting data from such studies and for the development of so-called humanised mouse models. CONCLUSION: It is of special importance to elucidate how a human gut microbiota influences bile acid composition and FXR signalling in colonised mice.
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Ácidos y Sales Biliares/metabolismo , Microbioma Gastrointestinal , Receptores Citoplasmáticos y Nucleares/metabolismo , Transducción de Señal , Animales , Bacterias/metabolismo , Ácidos y Sales Biliares/biosíntesis , Ácidos y Sales Biliares/química , Humanos , Ratones , Modelos BiológicosRESUMEN
BACKGROUND AND AIMS: Approximately 95% of bile acids (BAs) excreted into bile are reabsorbed in the gut and circulate back to the liver for further biliary secretion. Therefore, pharmacological inhibition of the ileal apical sodium-dependent BA transporter (ASBT/SLC10A2) may protect against BA-mediated cholestatic liver and bile duct injury. METHODS: Eight week old Mdr2(-/-) (Abcb4(-/-)) mice (model of cholestatic liver injury and sclerosing cholangitis) received either a diet supplemented with A4250 (0.01% w/w) - a highly potent and selective ASBT inhibitor - or a chow diet. Liver injury was assessed biochemically and histologically after 4weeks of A4250 treatment. Expression profiles of genes involved in BA homeostasis, inflammation and fibrosis were assessed via RT-PCR from liver and ileum homogenates. Intestinal inflammation was assessed by RNA expression profiling and immunohistochemistry. Bile flow and composition, as well as biliary and fecal BA profiles were analyzed after 1week of ASBT inhibitor feeding. RESULTS: A4250 improved sclerosing cholangitis in Mdr2(-/-) mice and significantly reduced serum alanine aminotransferase, alkaline phosphatase and BAs levels, hepatic expression of pro-inflammatory (Tnf-α, Vcam1, Mcp-1) and pro-fibrogenic (Col1a1, Col1a2) genes and bile duct proliferation (mRNA and immunohistochemistry for cytokeratin 19 (CK19)). Furthermore, A4250 significantly reduced bile flow and biliary BA output, which correlated with reduced Bsep transcription, while Ntcp and Cyp7a1 were induced. Importantly A4250 significantly reduced biliary BA secretion but preserved HCO3(-) and biliary phospholipid secretion resulting in an increased HCO3(-)/BA and PL/BA ratio. In addition, A4250 profoundly increased fecal BA excretion without causing diarrhea and altered BA pool composition, resulting in diminished concentrations of primary BAs tauro-ß-muricholic acid and taurocholic acid. CONCLUSIONS: Pharmacological ASBT inhibition attenuates cholestatic liver and bile duct injury by reducing biliary BA concentrations in mice.
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Ácidos y Sales Biliares/metabolismo , Conductos Biliares/efectos de los fármacos , Colangitis Esclerosante/tratamiento farmacológico , Colestasis/tratamiento farmacológico , Absorción Intestinal , Hígado/efectos de los fármacos , Transportadores de Anión Orgánico Sodio-Dependiente/antagonistas & inhibidores , Simportadores/antagonistas & inhibidores , Animales , Conductos Biliares/lesiones , Conductos Biliares/patología , Colestasis/metabolismo , Vesícula Biliar/efectos de los fármacos , Hígado/patología , RatonesRESUMEN
BACKGROUND: Bariatric surgery is an effective treatment option for obesity and provides long-term weight loss and positive effects on metabolism, but the underlying mechanisms are poorly understood. Alterations in bile acid metabolism have been suggested as a potential contributing factor, but comprehensive studies in humans are lacking. METHODS: In this study, we analysed the postprandial responses of bile acids, C4 and FGF19 in plasma, and excretion of bile acids in faeces, before and after bariatric surgery in patients (n = 38; 74% females) with obesity with or without type 2 diabetes from the BARIA cohort. FINDINGS: We observed that total fasting plasma bile acid levels increased, and faecal excretion of bile acids decreased after surgery suggesting increased reabsorption of bile acids. Consistent with increased bile acid levels after surgery we observed increased postprandial levels of FGF19 and suppression of the bile acid synthesis marker C4, suggesting increased FXR activation in the gut. We also noted that a subset of bile acids had altered postprandial responses before and after surgery. Finally, fasting plasma levels of 6α-hydroxylated bile acids, which are TGR5 agonists and associated with improved glucose metabolism, were increased after surgery and one of them, HDCA, covaried with diabetes remission in an independent cohort. INTERPRETATION: Our findings provide new insights regarding bile acid kinetics and suggest that bariatric surgery in humans alters bile acid profiles leading to activation of FXR and TGR5, which may contribute to weight loss, improvements in glucose metabolism, and diabetes remission. FUNDING: Novo Nordisk Fonden, Leducq Foundation, Swedish Heart-Lung Foundation, Knut and Alice Wallenberg Foundation, the ALF-agreement, ZonMw.
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Cirugía Bariátrica , Ácidos y Sales Biliares , Diabetes Mellitus Tipo 2 , Factores de Crecimiento de Fibroblastos , Obesidad , Humanos , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/cirugía , Diabetes Mellitus Tipo 2/sangre , Ácidos y Sales Biliares/metabolismo , Ácidos y Sales Biliares/sangre , Cirugía Bariátrica/métodos , Femenino , Masculino , Obesidad/cirugía , Obesidad/metabolismo , Obesidad/sangre , Persona de Mediana Edad , Adulto , Factores de Crecimiento de Fibroblastos/sangre , Factores de Crecimiento de Fibroblastos/metabolismo , Periodo Posprandial , Biomarcadores , Heces/química , Cinética , AyunoRESUMEN
Alterations in gut microbiota composition are suggested to contribute to cardiometabolic diseases, in part by producing bioactive molecules. Some of the metabolites are produced by very low abundant bacterial taxa, which largely have been neglected due to limits of detection. However, the concentration of microbially produced metabolites from these taxa can still reach high levels and have substantial impact on host physiology. To explore this concept, we focused on the generation of secondary bile acids by 7α-dehydroxylating bacteria and demonstrated that addition of a very low abundant bacteria to a community can change the metabolic output dramatically. We show that Clostridium scindens converts cholic acid into the secondary bile acid deoxycholic acid (DCA) very efficiently even though the abundance of C. scindens is low, but still detectable by digital droplet PCR. We also show that colonization of germ-free female mice with a community containing C. scindens induces DCA production and affects host metabolism. Finally, we show that DCA correlates with impaired glucose metabolism and a worsened lipid profile in individuals with type 2 diabetes, which implies that this metabolic pathway may contribute to the development of cardiometabolic disease.
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Ácido Desoxicólico , Diabetes Mellitus Tipo 2 , Microbioma Gastrointestinal , Glucosa , Ácido Desoxicólico/metabolismo , Animales , Microbioma Gastrointestinal/fisiología , Femenino , Glucosa/metabolismo , Ratones , Humanos , Diabetes Mellitus Tipo 2/microbiología , Diabetes Mellitus Tipo 2/metabolismo , Ratones Endogámicos C57BL , Clostridium/metabolismo , Clostridium/genética , Ácido Cólico/metabolismo , MasculinoRESUMEN
RAS and RHO proteins, which contribute to tumorigenesis and metastasis, undergo posttranslational modification with an isoprenyl lipid by protein farnesyltransferase (FTase) or protein geranylgeranyltransferase-I (GGTase-I). Inhibitors of FTase and GGTase-I were developed to block RAS-induced malignancies, but their utility has been difficult to evaluate because of off-target effects, drug resistance, and toxicity. Moreover, the impact of FTase deficiency and combined FTase/GGTase-I deficiency has not been evaluated with genetic approaches. We found that inactivation of FTase eliminated farnesylation of HDJ2 and H-RAS, prevented H-RAS targeting to the plasma membrane, and blocked proliferation of primary and K-RAS(G12D)-expressing fibroblasts. FTase inactivation in mice with K-RAS-induced lung cancer reduced tumor growth and improved survival, similar to results obtained previously with inactivation of GGTase-I. Simultaneous inactivation of FTase and GGTase-I markedly reduced lung tumors and improved survival without apparent pulmonary toxicity. These data shed light on the biochemical and therapeutic importance of FTase and suggest that simultaneous inhibition of FTase and GGTase-I could be useful in cancer therapeutics.
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Transformación Celular Neoplásica/metabolismo , Dimetilaliltranstransferasa/metabolismo , Neoplasias Pulmonares/enzimología , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Transferasas Alquil y Aril/genética , Transferasas Alquil y Aril/metabolismo , Alelos , Animales , Proliferación Celular , Transformación Celular Neoplásica/genética , Dimetilaliltranstransferasa/deficiencia , Modelos Animales de Enfermedad , Regulación Enzimológica de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/terapia , Ratones , Ratones Noqueados , Mutación , Proteínas Proto-Oncogénicas p21(ras)/genéticaRESUMEN
Bile salt export pump (Bsep) (Abcb11)-/- mice are protected from acquired cholestatic injury due to metabolic preconditioning with a hydrophilic bile acid (BA) pool with formation of tetrahydroxylated bile acids (THBAs). We aimed to explore whether loss of Bsep and subsequent elevation of THBA levels may have immunomodulatory effects, thus improving liver injury in the multidrug resistance protein 2 (Mdr2) (Abcb4)-/- mouse. Cholestatic liver injury in Mdr2-/- Bsep-/- double knockout (DKO), Mdr2-/- , Bsep-/- , and wild-type mice was studied for comparison. Mdr2-/- mice were treated with a THBA (3α,6α,7α,12α-Tetrahydroxycholanoic acid). RNA/protein expression of inflammatory/fibrotic markers were investigated. Serum BA-profiling was assessed by ultra-performance liquid chromatography tandem mass spectrometry. Hepatic immune cell profile was quantified by flow cytometric analysis (FACS). In vitro, the THBA effect on chenodeoxycholic acid (CDCA)-induced inflammatory signaling in hepatocyte and cholangiocytes as well as lipopolysaccharide (LPS)/interferon-γ (IFN-γ)-induced macrophage activation was analyzed. In contrast to Mdr2-/- , DKO mice showed no features of sclerosing cholangitis. Sixty-seven percent of serum BAs in DKO mice were polyhydroxylated (mostly THBAs), whereas Mdr2-/- mice did not have these BAs. Compared with Mdr2-/- , DKO animals were protected from hepatic inflammation/fibrosis. THBA feeding in Mdr2-/- mice improved liver injury. FACS analysis in DKO and Mdr2-/- THBA-fed mice showed changes of the hepatic immune cell profile towards an anti-inflammatory pattern. Early growth response 1 (EGR1) protein expression was reduced in DKO and in Mdr2-/- THBA-fed mice compared with Mdr2-/- control mice. In vitro, THBA-reduced CDCA induced EGR1 protein and mRNA expression of inflammatory markers in hepatocytes and cholangiocytes. LPS/IFN-γ-induced macrophage activation was ameliorated by THBA. THBAs repress EGR1-related key pro-inflammatory pathways. Conclusion: THBA and their downstream targets may represent a potential treatment strategy for cholestatic liver diseases.
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Ácidos y Sales Biliares , Colangitis Esclerosante , Colestasis , Subfamilia B de Transportador de Casetes de Unión a ATP/genética , Animales , Ácidos y Sales Biliares/química , Ácidos y Sales Biliares/farmacología , Conductos Biliares/patología , Colangitis Esclerosante/genética , Colestasis/complicaciones , Colestasis/genética , Modelos Animales de Enfermedad , Inmunomodulación/efectos de los fármacos , Interferón gamma , Lipopolisacáridos/farmacología , Cirrosis Hepática/genética , Ratones , Ratones Noqueados , Miembro 4 de la Subfamilia B de Casete de Unión a ATPRESUMEN
Hyperactive RAS signaling is caused by mutations in RAS genes or a deficiency of the neurofibromatosis gene (NF1) and is common in myeloid malignancies. In mice, expression of oncogenic K-RAS or inactivation of Nf1 in hematopoietic cells results in myeloproliferative disorders (MPDs) that do not progress to acute myeloid leukemia (AML). Because NF1 is a RAS-GTPase-activating protein it has been proposed that NF1 deficiency is functionally equivalent to an oncogenic RAS. It is not clear, however, whether Nf1 deficiency would be redundant in K-RAS-induced MPD development or whether the 2 mutations would cooperate in leukemogenesis. Here, we show that the simultaneous inactivation of Nf1 and expression of K-RAS(G12D) in mouse hematopoietic cells results in AML that was fatal in primary mice within 4 weeks and transplantable to sublethally irradiated secondary recipients. The data point to a strong cooperation between Nf1 deficiency and oncogenic K-RAS.