| 1. |
- Mardinoglu, Adil, 1982, et al.
(författare)
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Personal model-assisted identification of NAD(+) and glutathione metabolism as intervention target in NAFLD
- 2017
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Ingår i: Molecular Systems Biology. - : EMBO. - 1744-4292. ; 13:3
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Tidskriftsartikel (refereegranskat)abstract
- To elucidate the molecular mechanisms underlying non-alcoholic fatty liver disease (NAFLD), we recruited 86 subjects with varying degrees of hepatic steatosis (HS). We obtained experimental data on lipoprotein fluxes and used these individual measurements as personalized constraints of a hepatocyte genome-scale metabolic model to investigate metabolic differences in liver, taking into account its interactions with other tissues. Our systems level analysis predicted an altered demand for NAD(+) and glutathione (GSH) in subjects with high HS. Our analysis and metabolomic measurements showed that plasma levels of glycine, serine, and associated metabolites are negatively correlated with HS, suggesting that these GSH metabolism precursors might be limiting. Quantification of the hepatic expression levels of the associated enzymes further pointed to altered de novo GSH synthesis. To assess the effect of GSH and NAD(+) repletion on the development of NAFLD, we added precursors for GSH and NAD(+) biosynthesis to the Western diet and demonstrated that supplementation prevents HS in mice. In a proof-of-concept human study, we found improved liver function and decreased HS after supplementation with serine (a precursor to glycine) and hereby propose a strategy for NAFLD treatment.
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| 2. |
- Zhang, C., et al.
(författare)
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The acute effect of metabolic cofactor supplementation: a potential therapeutic strategy against non-alcoholic fatty liver disease
- 2020
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Ingår i: Molecular Systems Biology. - : EMBO. - 1744-4292. ; 16:4
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Tidskriftsartikel (refereegranskat)abstract
- The prevalence of non-alcoholic fatty liver disease (NAFLD) continues to increase dramatically, and there is no approved medication for its treatment. Recently, we predicted the underlying molecular mechanisms involved in the progression of NAFLD using network analysis and identified metabolic cofactors that might be beneficial as supplements to decrease human liver fat. Here, we first assessed the tolerability of the combined metabolic cofactors including l-serine, N-acetyl-l-cysteine (NAC), nicotinamide riboside (NR), and l-carnitine by performing a 7-day rat toxicology study. Second, we performed a human calibration study by supplementing combined metabolic cofactors and a control study to study the kinetics of these metabolites in the plasma of healthy subjects with and without supplementation. We measured clinical parameters and observed no immediate side effects. Next, we generated plasma metabolomics and inflammatory protein markers data to reveal the acute changes associated with the supplementation of the metabolic cofactors. We also integrated metabolomics data using personalized genome-scale metabolic modeling and observed that such supplementation significantly affects the global human lipid, amino acid, and antioxidant metabolism. Finally, we predicted blood concentrations of these compounds during daily long-term supplementation by generating an ordinary differential equation model and liver concentrations of serine by generating a pharmacokinetic model and finally adjusted the doses of individual metabolic cofactors for future human clinical trials.
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| 3. |
- 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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| 4. |
- Nuñez Durán, Esther, et al.
(författare)
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Protein kinase STK25 aggravates the severity of non-alcoholic fatty pancreas disease in mice
- 2017
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Ingår i: Journal of Endocrinology. - : Bioscientifica. - 0022-0795 .- 1479-6805. ; 234:1, s. 15-27
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Tidskriftsartikel (refereegranskat)abstract
- Characterising the molecular networks that negatively regulate pancreatic beta-cell function is essential for understanding the underlying pathogenesis and developing new treatment strategies for type 2 diabetes. We recently identified serine/threonine protein kinase 25 (STK25) as a critical regulator of ectopic fat storage, meta-inflammation, and fibrosis in liver and skeletal muscle. Here, we assessed the role of STK25 in control of progression of non-alcoholic fatty pancreas disease in the context of chronic exposure to dietary lipids in mice. We found that overexpression of STK25 in high-fat-fed transgenic mice aggravated diet-induced lipid storage in the pancreas compared with that of wild-type controls, which was accompanied by exacerbated pancreatic inflammatory cell infiltration, stellate cell activation, fibrosis and apoptosis. Pancreas of Stk25 transgenic mice also displayed a marked decrease in islet beta/alpha-cell ratio and alteration in the islet architecture with an increased presence of a-cells within the islet core, whereas islet size remained similar between genotypes. After a continued challenge with a high-fat diet, lower levels of fasting plasma insulin and C-peptide, and higher levels of plasma leptin, were detected in Stk25 transgenic vs wild-type mice. Furthermore, the glucose-stimulated insulin secretion was impaired in high-fat-fed Stk25 transgenic mice during glucose tolerance test, in spite of higher net change in blood glucose concentrations compared with wild-type controls, suggesting islet beta-cell dysfunction. In summary, this study unravels a role for STK25 in determining the susceptibility to diet-induced nonalcoholic fatty pancreas disease in mice in connection to obesity. Our findings highlight STK25 as a potential drug target for metabolic disease.
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| 5. |
- Cansby, Emmelie, 1984, et al.
(författare)
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Silencing of STE20-type kinase STK25 in human aortic endothelial and smooth muscle cells is atheroprotective
- 2022
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 5, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies highlight the importance of lipotoxic damage in aortic cells as the major pathogenetic contributor to atherosclerotic disease. Since the STE20-type kinase STK25 has been shown to exacerbate ectopic lipid storage and associated cell injury in several metabolic organs, we here investigate its role in the main cell types of vasculature. We depleted STK25 by small interfering RNA in human aortic endothelial and smooth muscle cells exposed to oleic acid and oxidized LDL. In both cell types, the silencing of STK25 reduces lipid accumulation and suppresses activation of inflammatory and fibrotic pathways as well as lowering oxidative and endoplasmic reticulum stress. Notably, in smooth muscle cells, STK25 inactivation hinders the shift from a contractile to a synthetic phenotype. Together, we provide several lines of evidence that antagonizing STK25 signaling in human aortic endothelial and smooth muscle cells is atheroprotective, highlighting this kinase as a new potential therapeutic target for atherosclerotic disease.
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| 6. |
- Caputo, Mara, et al.
(författare)
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Silencing of STE20-type kinase MST3 in mice with antisense oligonucleotide treatment ameliorates diet-induced nonalcoholic fatty liver disease
- 2021
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Ingår i: FASEB Journal. - 0892-6638. ; 35:5
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Tidskriftsartikel (refereegranskat)abstract
- Nonalcoholic fatty liver disease (NAFLD) is emerging as a leading cause of chronic liver disease worldwide. Despite intensive nonclinical and clinical research in this field, no specific pharmacological therapy is currently approved to treat NAFLD, which has been recognized as one of the major unmet medical needs of the 21st century. Our recent studies have identified STE20-type kinase MST3, which localizes to intracellular lipid droplets, as a critical regulator of ectopic fat accumulation in human hepatocytes. Here, we explored whether treatment with Mst3-targeting antisense oligonucleotides (ASOs) can promote hepatic lipid clearance and mitigate NAFLD progression in mice in the context of obesity. We found that administration of Mst3-targeting ASOs in mice effectively ameliorated the full spectrum of high-fat diet-induced NAFLD including liver steatosis, inflammation, fibrosis, and hepatocellular damage. Mechanistically, Mst3 ASOs suppressed lipogenic gene expression, as well as acetyl-CoA carboxylase (ACC) protein abundance, and substantially reduced lipotoxicity-mediated oxidative and endoplasmic reticulum stress in the livers of obese mice. Furthermore, we found that MST3 protein levels correlated positively with the severity of NAFLD in human liver biopsies. In summary, this study provides the first in vivo evidence that antagonizing MST3 signaling is sufficient to mitigate NAFLD progression in conditions of excess dietary fuels and warrants future investigations to assess whether MST3 inhibitors may provide a new strategy for the treatment of patients with NAFLD.
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| 7. |
- Caputo, Mara, et al.
(författare)
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STE20-type kinases MST3 and MST4 promote the progression of hepatocellular carcinoma: Evidence from human cell culture and expression profiling of liver biopsies
- 2023
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Ingår i: Faseb Journal. - 0892-6638. ; 37:8
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Tidskriftsartikel (refereegranskat)abstract
- Hepatocellular carcinoma (HCC) is one of the most fatal and fastest growing malignancies. Recently, nonalcoholic steatohepatitis (NASH), characterized by liver steatosis, inflammation, cell injury (hepatocyte ballooning), and different stages of fibrosis, has emerged as a major catalyst for HCC. Because the STE20-type kinases, MST3 and MST4, have been described as critical molecular regulators of NASH pathophysiology, we here focused on determining the relevance of these proteins in human HCC. By analyzing public datasets and in-house cohorts, we found that hepatic MST3 and MST4 expression was positively correlated with the incidence and severity of HCC. We also found that the silencing of both MST3 and MST4, but also either of them individually, markedly suppressed the tumorigenesis of human HCC cells including attenuated proliferation, migration, invasion, and epithelial-mesenchymal transition. Mechanistic investigations revealed lower activation of STAT3 signaling in MST3/MST4-deficient hepatocytes and identified GOLGA2 and STRIPAK complex as the binding partners of both MST3 and MST4. These findings reveal that MST3 and MST4 play a critical role in promoting the progression of HCC and suggest that targeting these kinases may provide a novel strategy for the treatment of liver cancer.
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| 8. |
- Caputo, Mara, et al.
(författare)
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STE20-Type Protein Kinase MST4 Controls NAFLD Progression by Regulating Lipid Droplet Dynamics and Metabolic Stress in Hepatocytes
- 2021
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Ingår i: Hepatology Communications. - : Ovid Technologies (Wolters Kluwer Health). - 2471-254X. ; 5:7, s. 1183-1200
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Tidskriftsartikel (refereegranskat)abstract
- Nonalcoholic fatty liver disease (NAFLD) has emerged as a leading cause of chronic liver disease worldwide, primarily because of the massive global increase in obesity. Despite intense research efforts in this field, the factors that govern the initiation and subsequent progression of NAFLD are poorly understood, which hampers the development of diagnostic tools and effective therapies in this area of high unmet medical need. Here we describe a regulator in molecular pathogenesis of NAFLD: STE20-type protein kinase MST4. We found that MST4 expression in human liver biopsies was positively correlated with the key features of NAFLD (i.e., hepatic steatosis, lobular inflammation, and hepatocellular ballooning). Furthermore, the silencing of MST4 attenuated lipid accumulation in human hepatocytes by stimulating beta-oxidation and triacylglycerol secretion, while inhibiting fatty acid influx and lipid synthesis. Conversely, overexpression of MST4 in human hepatocytes exacerbated fat deposition by suppressing mitochondrial fatty acid oxidation and triacylglycerol efflux, while enhancing lipogenesis. In parallel to these reciprocal alterations in lipid storage, we detected substantially decreased or aggravated oxidative/endoplasmic reticulum stress in human hepatocytes with reduced or increased MST4 levels, respectively. Interestingly, MST4 protein was predominantly associated with intracellular lipid droplets in both human and rodent hepatocytes. Conclusion: Together, our results suggest that hepatic lipid droplet-decorating protein MST4 is a critical regulatory node governing susceptibility to NAFLD and warrant future investigations to address the therapeutic potential of MST4 antagonism as a strategy to prevent or mitigate the development and aggravation of this disease.
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| 9. |
- Jungwirth, E., et al.
(författare)
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Meta-analysis and Consolidation of Farnesoid X Receptor Chromatin Immunoprecipitation Sequencing Data Across Different Species and Conditions
- 2021
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Ingår i: Hepatology Communications. - : Ovid Technologies (Wolters Kluwer Health). - 2471-254X. ; 5:10, s. 1721-1736
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Tidskriftsartikel (refereegranskat)abstract
- Farnesoid X receptor (FXR) is a nuclear receptor that controls gene regulation of different metabolic pathways and represents an upcoming drug target for various liver diseases. Several data sets on genome-wide FXR binding in different species and conditions exist. We have previously reported that these data sets are heterogeneous and do not cover the full spectrum of potential FXR binding sites. Here, we report the first meta-analysis of all publicly available FXR chromatin immunoprecipitation sequencing (ChIP-seq) data sets from mouse, rat, and human across different conditions using a newly generated analysis pipeline. All publicly available single data sets were biocurated in a standardized manner and compared on every relevant level from raw reads to affected functional pathways. Individual murine data sets were then virtually merged into a single unique "FXR binding atlas" spanning all potential binding sites across various conditions. Comparison of the single biocurated data sets showed that the overlap of FXR binding sites between different species is modest and ranges from 48% (mouse-human) to 55% (mouse-rat). Moreover, in vivo data among different species are more similar than human in vivo data compared to human in vitro data. The consolidated murine global FXR binding atlas virtually increases sequencing depth and allows recovering more and novel potential binding sites and signaling pathways that were missed in the individual data sets. The FXR binding atlas is publicly searchable (). Conclusion: Published single FXR ChIP-seq data sets and large-scale integrated omics data sets do not cover the full spectrum of FXR binding. Combining different individual data sets and creating an "FXR super-binding atlas" enhances understanding of FXR signaling capacities across different conditions. This is important when considering the potential wide spectrum for drugs targeting FXR in liver diseases.
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| 10. |
- Kumar Anand, Sumit, et al.
(författare)
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Inhibition of MAP4K4 signaling initiates metabolic reprogramming to protect hepatocytes from lipotoxic damage
- 2022
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Ingår i: Journal of Lipid Research. - : Elsevier BV. - 0022-2275. ; 63:7
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Tidskriftsartikel (refereegranskat)abstract
- The primary hepatic consequence of obesity is non-alcoholic fatty liver disease (NAFLD), affecting about 25% of the global adult population. Non-alcoholic steatohepatitis (NASH) is a severe form of NAFLD characterized by liver lipid accumulation, inflammation, and hepatocyte ballooning, with a different degree of hepatic fibrosis. In the light of rapidly increasing prevalence of NAFLD and NASH, there is an urgent need for improved understanding of the molecular pathogenesis of these diseases. The aim of this study was to decipher the possible role of STE20-type kinase MAP4K4 in the regulation of he-patocellular lipotoxicity and susceptibility to NAFLD. We found that MAP4K4 mRNA expression in human liver biopsies was positively correlated with key hallmarks of NAFLD (i.e., liver steatosis, lobular inflammation, hepatocellular ballooning, and fibrosis). We also found that the silencing of MAP4K4 suppressed lipid deposition in human he-patocytes by stimulating beta-oxidation and tri-acylglycerol secretion, while attenuating fatty acid influx and lipid synthesis. Furthermore, down -regulation of MAP4K4 markedly reduced the glycolysis rate and lowered incidences of oxidative/ endoplasmic reticulum stress. In parallel, we observed suppressed JNK and ERK and increased AKT phosphorylation in MAP4K4-deficient hep-atocytes. Together, these results provide the first experimental evidence supporting the potential involvement of STE20-type kinase MAP4K4 as a component of the hepatocellular lipotoxic milieu promoting NAFLD susceptibility.
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