| 1. |
- Schneider, K. M., et al.
(författare)
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Imbalanced gut microbiota fuels hepatocellular carcinoma development by shaping the hepatic inflammatory microenvironment
- 2022
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide, and therapeutic options for advanced HCC are limited. Here, we observe that intestinal dysbiosis affects antitumor immune surveillance and drives liver disease progression towards cancer. Dysbiotic microbiota, as seen in Nlrp6(-/-) mice, induces a Toll-like receptor 4 dependent expansion of hepatic monocytic myeloid-derived suppressor cells (mMDSC) and suppression of T-cell abundance. This phenotype is transmissible via fecal microbiota transfer and reversible upon antibiotic treatment, pointing to the high plasticity of the tumor microenvironment. While loss of Akkermansia muciniphila correlates with mMDSC abundance, its reintroduction restores intestinal barrier function and strongly reduces liver inflammation and fibrosis. Cirrhosis patients display increased bacterial abundance in hepatic tissue, which induces pronounced transcriptional changes, including activation of fibro-inflammatory pathways as well as circuits mediating cancer immunosuppression. This study demonstrates that gut microbiota closely shapes the hepatic inflammatory microenvironment opening approaches for cancer prevention and therapy. Steatohepatitis is a chronic hepatic inflammation associated with increased risk of hepatocellular carcinoma progression. Here the authors show that intestinal dysbiosis in mice lacking the inflammasome sensor molecule NLRP6 aggravates steatohepatitis and accelerates liver cancer progression, a process that can be delayed by antibiotic treatment.
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| 2. |
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| 3. |
- Schneider, K. M., et al.
(författare)
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Gut microbiota depletion exacerbates cholestatic liver injury via loss of FXR signalling
- 2021
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Ingår i: Nature Metabolism. - : Springer Science and Business Media LLC. - 2522-5812. ; 3:9, s. 1228-1241
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Tidskriftsartikel (refereegranskat)abstract
- Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown aetiology for which there are no approved therapeutic options. Patients with PSC display changes in gut microbiota and in bile acid (BA) composition; however, the contribution of these alterations to disease pathogenesis remains controversial. Here we identify a role for microbiota-dependent changes in BA synthesis that modulates PSC pathophysiology. In a genetic mouse model of PSC, we show that loss of microbiota-mediated negative feedback control of BA synthesis results in increased hepatic BA concentrations, disruption of bile duct barrier function and, consequently, fatal liver injury. We further show that these changes are dependent on decreased BA signalling to the farnesoid X receptor, which modulates the activity of the rate-limiting enzyme in BA synthesis, CYP7A1. Moreover, patients with advanced stages of PSC show suppressed BA synthesis as measured by serum C4 levels, which is associated with poor disease prognosis. Our preclinical data highlight the microbiota-dependent dynamics of BA metabolism in cholestatic liver disease, which could be important for future therapies targeting BA and gut microbiome interactions, and identify C4 as a potential biomarker to functionally stratify patients with PSC and predict disease outcomes. Patients with primary sclerosing cholangitis (PSC), a chronic cholestatic liver disease, display changes in the gut microbiota and in bile acid composition. Schneider, Candels and colleagues identify a role for microbiota-dependent regulation of bile acid synthesis through farnesoid X receptor signalling, which is relevant for PSC disease progression.
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| 6. |
- Gui, W. F., et al.
(författare)
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Colitis ameliorates cholestatic liver disease via suppression of bile acid synthesis
- 2023
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Ingår i: Nature Communications. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by chronic inflammation and progressive fibrosis of the biliary tree. The majority of PSC patients suffer from concomitant inflammatory bowel disease (IBD), which has been suggested to promote disease development and progression. However, the molecular mechanisms by which intestinal inflammation may aggravate cholestatic liver disease remain incompletely understood. Here, we employ an IBD-PSC mouse model to investigate the impact of colitis on bile acid metabolism and cholestatic liver injury. Unexpectedly, intestinal inflammation and barrier impairment improve acute cholestatic liver injury and result in reduced liver fibrosis in a chronic colitis model. This phenotype is independent of colitis-induced alterations of microbial bile acid metabolism but mediated via hepatocellular NF-kappa B activation by lipopolysaccharide (LPS), which suppresses bile acid metabolism in-vitro and in-vivo. This study identifies a colitis-triggered protective circuit suppressing cholestatic liver disease and encourages multi-organ treatment strategies for PSC.
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| 7. |
- Fucho, Raquel, et al.
(författare)
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ASMase regulates autophagy and lysosomal membrane permeabilization and its inhibition prevents early stage non-alcoholic steatohepatitis
- 2014
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Ingår i: Journal of Hepatology. - : Elsevier. - 0168-8278 .- 1600-0641. ; 61:5, s. 1126-1134
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aims: Acid sphingomyelinase (ASMase) is activated in non-alcoholic steatohepatitis (NASH). However, the contribution of ASMase to NASH is poorly understood and limited to hepatic steatosis and glucose metabolism. Here we examined the role of ASMase in high fat diet (HFD)-induced NASH. Methods: Autophagy, endoplasmic reticulum (ER) stress and lysosomal membrane permeabilization (LMP) were determined in ASMase(-/-) mice fed a HFD. The impact of pharmacological ASMase inhibition on NASH was analyzed in wild type mice fed a HFD. Results: ASMase deficiency determined resistance to hepatic steatosis mediated by a HFD or methionine-choline deficient diet. ASMase(-/-) mice were resistant to HFD-induced hepatic ER stress, but sensitive to tunicamycin-mediated ER stress, indicating selectivity in the resistance of ASMase(-/-) mice to ER stress and steatosis. Autophagic flux, determined in the presence of rapamycin and/or chloroquine, was lower in primary mouse hepatocytes (PMH) from ASMase(-/-) mice and accompanied by increased p62 levels, suggesting autophagic impairment. Moreover, autophagy suppression by chloroquine and brefeldin A caused ER stress in PMH from ASMase(+/+) mice but not in ASMase(-/-) mice. ASMase(-/-) PMH exhibited increased lysosomal cholesterol loading, decreased LMP and apoptosis resistance induced by 0-methylserine dodecylamide hydrochloride or palmitic acid, effects that were reversed by decreasing cholesterol levels by oxysterol 25-hydroxycholesterol. In vivo pharmacological ASMase inhibition by amitriptyline, a widely used tricyclic antidepressant, protected wild type mice against HFD-induced hepatic steatosis, fibrosis, and liver damage, effects indicative of early-stage NASH, Conclusions: These findings underscore a critical role for ASMase in diet-induced NASH and suggest the potential of amitriptyline as a treatment for patients with NASH.
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| 11. |
- Braadland, P. R., et al.
(författare)
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Suppression of bile acid synthesis as a tipping point in the disease course of primary sclerosing cholangitis
- 2022
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Ingår i: Jhep Reports. - : Elsevier BV. - 2589-5559. ; 4:11
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Tidskriftsartikel (refereegranskat)abstract
- Background & Aims: Farnesoid X receptor (FXR) agonists and fibroblast growth factor 19 (FGF19) analogues suppress bile acid synthesis and are being investigated for their potential therapeutic efficacy in cholestatic liver diseases. We investigated whether bile acid synthesis associated with outcomes in 2 independent populations of people with primary sclerosing cholangitis (PSC) not receiving such therapy.Methods: Concentrations of individual bile acids and 7a-hydroxy-4-cholesten-3-one (C4) were measured in blood samples from 330 patients with PSC attending tertiary care hospitals in the discovery and validation cohorts and from 100 healthy donors. We used a predefined multivariable Cox proportional hazards model to evaluate the prognostic value of C4 to predict liver transplantation-free survival and evaluated its performance in the validation cohort. Results: The bile acid synthesis marker C4 was negatively associated with total bile acids. Patients with fully suppressed bile acid synthesis had strongly elevated total bile acids and short liver transplantation-free survival. In multivariable models, a 50% reduction in C4 corresponded to increased hazards for liver transplantation or death in both the discovery (adjusted hazard ratio [HR] = 1.24, 95% CI 1.06-1.43) and validation (adjusted HR = 1.23, 95% CI 1.03-1.47) cohorts. Adding C4 to established risk scores added value to predict future events, and predicted survival probabilities were well calibrated externally. There was no discernible impact of ursodeoxycholic acid treatment on bile acid synthesis.Conclusions: Bile acid accumulation-associated suppression of bile acid synthesis was apparent in patients with advanced PSC and associated with reduced transplantation-free survival. In a subset of the patients, bile acid synthesis was likely suppressed beyond a tipping point at which any further pharmacological suppression may be futile. Implications for patient stratification and inclusion criteria for clinical trials in PSC warrant further investigation.Lay summary: We show, by measuring the level of the metabolite C4 in the blood from patients with primary sclerosing cholangitis (PSC), that low production of bile acids in the liver predicts a more rapid progression to severe disease. Many people with PSC appear to have fully suppressed bile acid production, and both established and new drugs that aim to reduce bile acid production may therefore be futile for them. We propose C4 as a test to find those likely to respond to these treatments.(c) 2022 The Authors. Published by Elsevier B.V. on behalf of European Association for the Study of the Liver (EASL). This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 12. |
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| 13. |
- Gavin, Michael C., et al.
(författare)
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Toward a Mechanistic Understanding of Linguistic Diversity
- 2013
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Ingår i: BioScience. - : Oxford University Press (OUP). - 0006-3568 .- 1525-3244. ; 63:7, s. 524-535
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Tidskriftsartikel (refereegranskat)abstract
- Our species displays remarkable linguistic diversity. Although the uneven distribution of this diversity demands explanation, the drivers of these patterns have not been conclusively determined. We address this issue in two steps: First, we review previous empirical studies whose authors have suggested environmental, geographical, and sociocultural drivers of linguistic diversification. However, contradictory results and methodological variation make it difficult to draw general conclusions. Second, we outline a program for future research. We suggest that future analyses should account for interactions among causal factors, the lack of spatial and phylogenetic independence of the data, and transitory patterns. Recent analytical advances in biogeography and evolutionary biology, such as simulation modeling of diversity patterns, hold promise for testing four key mechanisms of language diversification proposed here: neutral change, population movement, contact, and selection. Future modeling approaches should also evaluate how the outcomes of these processes are influenced by demography, environmental heterogeneity, and time.
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| 14. |
- Haange, S. B., et al.
(författare)
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Ring Trial on Quantitative Assessment of Bile Acids Reveals a Method- and Analyte-Specific Accuracy and Reproducibility
- 2022
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Ingår i: Metabolites. - : MDPI AG. - 2218-1989. ; 12:7
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Tidskriftsartikel (refereegranskat)abstract
- Bile acids are a key mediator of the molecular microbiome-host interaction, and various mass spectrometry-based assays have been developed in the recent decade to quantify a wide range of bile acids. We compare existing methodologies to harmonize them. Methodology for absolute quantification of bile acids from six laboratories in Europe were compared for the quantification of the primary bile acids cholic acid (CA) and chenodeoxycholic acid (CDCA) and conjugated products glycocholic acid (GCA) and taurocholic acid (TCA). For the bacterially modified secondary bile acids, the quantification of deoxycholic acid (DCA) and lithocholic acid (LCA) was compared. For the murine bile acids, we used the primary muricholic acids (alpha-MCA and, beta-MCA) and the intestinally produced secondary bile acid muricholic (omega-MCA). The standards were spiked into methanol:water (1:1) mix as well as in human and murine serum at either low concentration range (150-3000 nM) or high concentration range (1500-40,000 nM). The precision was better for higher concentrations. Measurements for the hydrophobic unconjugated bile acids LCA and omega-MCA were the most challenging. The quality assessments were generally very similar, and the comprehensive analyses demonstrated that data from chosen locations can be used for comparisons between studies.
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| 15. |
- Liao, Lijun, et al.
(författare)
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Intestinal dysbiosis augments liver disease progression via NLRP3 in a murine model of primary sclerosing cholangitis.
- 2019
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Ingår i: Gut. - : BMJ. - 1468-3288 .- 0017-5749. ; 68:8, s. 1477-92
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Tidskriftsartikel (refereegranskat)abstract
- 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).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 52weeks, 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.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.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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| 16. |
- Sarmiento Nova, Silvia J., et al.
(författare)
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Response Surface Method strategies coupled with NLFEA for structural reliability analysis of prestressed bridges
- 2021
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Ingår i: IABSE Congress Ghent 2021. - Zurich, Switzerland : International Association for Bridge and Structural Engineering (IABSE). ; , s. 1813-1822
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Konferensbidrag (refereegranskat)abstract
- The Response Surface Method (RSM) has become an essential tool to solve structural reliability problems due to its accuracy, efficacy, and facility for coupling with Nonlinear Finite Element Analysis (NLFEA). In this paper, some strategies to improve the RSM efficacy without compromising its accuracy are tested. Initially, each strategy is implemented to assess the safety level of a highly nonlinear explicit limit state function. The strategy with the best results is then identified and used to carry out a reliability analysis of a prestressed concrete bridge, considering the nonlinear material behavior through NLFEA simulation. The calculated value of ? is compared with the target value established in Eurocode for ULS. The results showed how RSM can be a practical methodology and how the improvements presented can reduce the computational cost of a traditional RSM giving a good alternative to simulation methods such as Monte Carlo.
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| 17. |
- Su, H., et al.
(författare)
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Long-term hypercaloric diet exacerbates metabolic liver disease in PNPLA3 I148M animals
- 2023
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Ingår i: Liver International. - 1478-3223. ; 43:8, s. 1699-1713
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Tidskriftsartikel (refereegranskat)abstract
- Background & AimsNonalcoholic fatty liver disease (NAFLD) is a major health burden associated with the metabolic syndrome leading to liver fibrosis, cirrhosis and ultimately liver cancer. In humans, the PNPLA3 I148M polymorphism of the phospholipase patatin-like phospholipid domain containing protein 3 (PNPLA3) has a well-documented impact on metabolic liver disease. In this study, we used a mouse model mimicking the human PNPLA3 I148M polymorphism in a long-term high fat diet (HFD) experiment to better define its role for NAFLD progression. MethodsMale mice bearing wild-type Pnpla3 (Pnpla3(WT)), or the human polymorphism PNPLA3 I148M (Pnpla3(148M/M)) were subjected to HFD feeding for 24 and 52 weeks. Further analysis concerning basic phenotype, inflammation, proliferation and cell death, fibrosis and microbiota were performed in each time point. ResultsAfter 52 weeks HFD Pnpla3(148M/M) animals had more liver fibrosis, enhanced numbers of inflammatory cells as well as increased Kupffer cell activity. Increased hepatocyte cell turnover and ductular proliferation were evident in HFD Pnpla3(148M/M) livers. Microbiome diversity was decreased after HFD feeding, changes were influenced by HFD feeding (36%) and the PNPLA3 I148M genotype (12%). Pnpla3(148M/M) mice had more faecal bile acids. RNA-sequencing of liver tissue defined an HFD-associated signature, and a Pnpla3(148M/M) specific pattern, which suggests Kupffer cell and monocytes-derived macrophages as significant drivers of liver disease progression in Pnpla3(148M/M) animals. ConclusionWith long-term HFD feeding, mice with the PNPLA3 I148M genotype show exacerbated NAFLD. This finding is linked to PNPLA3 I148M-specific changes in microbiota composition and liver gene expression showing a stronger inflammatory response leading to enhanced liver fibrosis progression.
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