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17 Publications visible to you, out of a total of 17

Abstract (Expand)

The hepatic Na+-taurocholate cotransporting polypeptide NTCP/SLC10A1 is important for the uptake of bile salts and selected drugs. Its inhibition results in increased systemic bile salt concentrations.oncentrations. NTCP is also the entry receptor for the hepatitis B/D virus. We investigated interindividual hepatic SLC10A1/NTCP expression using various omics technologies. SLC10A1/NTCP mRNA expression/protein abundance was quantified in well-characterized 143 human livers by real-time PCR and LC-MS/MS-based targeted proteomics. Genome-wide SNP arrays and SLC10A1 next-generation sequencing were used for genomic analyses. SLC10A1 DNA methylation was assessed through MALDI-TOF MS. Transcriptomics and untargeted metabolomics (UHPLC-Q-TOF-MS) were correlated to identify NTCP-related metabolic pathways. SLC10A1 mRNA and NTCP protein levels varied 44-fold and 10.4-fold, respectively. Non-genetic factors (e.g., smoking, alcohol consumption) influenced significantly NTCP expression. Genetic variants in SLC10A1 or other genes do not explain expression variability which was validated in livers (n = 50) from The Cancer Genome Atlas. The identified two missense SLC10A1 variants did not impair transport function in transfectants. Specific CpG sites in SLC10A1 as well as single metabolic alterations and pathways (e.g., peroxisomal and bile acid synthesis) were significantly associated with expression. Inter-individual variability of NTCP expression is multifactorial with the contribution of clinical factors, DNA methylation, transcriptional regulation as well as hepatic metabolism, but not genetic variation.

Authors: Roman Tremmel, Anne T. Nies, Barbara A. C. van Eijck, Niklas Handin, Mathias Haag, Stefan Winter, Florian A. Büttner, Charlotte Kölz, Franziska Klein, Pascale Mazzola, Ute Hofmann, Kathrin Klein, Per Hoffmann, Markus M. Nöthen, Fabienne Z. Gaugaz, Per Artursson, Matthias Schwab, Elke Schaeffeler

Date Published: 1st Jul 2022

Publication Type: Journal

Abstract (Expand)

The Hedgehog signaling pathway regulates many processes during embryogenesis and the homeostasis of adult organs. Recent data suggest that central metabolic processes and signaling cascades in the liver are controlled by the Hedgehog pathway and that changes in hepatic Hedgehog activity also affect peripheral tissues, such as the reproductive organs in females. Here, we show that hepatocyte-specific deletion of the Hedgehog pathway is associated with the dramatic expansion of adipose tissue in mice, the overall phenotype of which does not correspond to the classical outcome of insulin resistance-associated diabetes type 2 obesity. Rather, we show that alterations in the Hedgehog signaling pathway in the liver lead to a metabolic phenotype that is resembling metabolically healthy obesity. Mechanistically, we identified an indirect influence on the hepatic secretion of the fibroblast growth factor 21, which is regulated by a series of signaling cascades that are directly transcriptionally linked to the activity of the Hedgehog transcription factor GLI1. The results of this study impressively show that the metabolic balance of the entire organism is maintained via the activity of morphogenic signaling pathways, such as the Hedgehog cascade. Obviously, several pathways are orchestrated to facilitate liver metabolic status to peripheral organs, such as adipose tissue.

Authors: F. Ott, C. Korner, K. Werner, M. Gericke, I. Liebscher, D. Lobsien, S. Radrezza, A. Shevchenko, U. Hofmann, J. Kratzsch, R. Gebhardt, T. Berg, M. Matz-Soja

Date Published: 18th May 2022

Publication Type: Journal

Abstract (Expand)

The Hedgehog signaling pathway regulates many processes during embryogenesis and the homeostasis of adult organs. Recent data suggest that central metabolic processes and signaling cascades in the livers in the liver are controlled by the Hedgehog pathway and that changes in hepatic Hedgehog activity also affect peripheral tissues, such as the reproductive organs in females. Here, we show that hepatocyte-specific deletion of the Hedgehog pathway is associated with the dramatic expansion of adipose tissue in mice, the overall phenotype of which does not correspond to the classical outcome of insulin resistance-associated diabetes type 2 obesity. Rather, we show that alterations in the Hedgehog signaling pathway in the liver lead to a metabolic phenotype that is resembling metabolically healthy obesity. Mechanistically, we identified an indirect influence on the hepatic secretion of the fibroblast growth factor 21, which is regulated by a series of signaling cascades that are directly transcriptionally linked to the activity of the Hedgehog transcription factor GLI1. The results of this study impressively show that the metabolic balance of the entire organism is maintained via the activity of morphogenic signaling pathways, such as the Hedgehog cascade. Obviously, several pathways are orchestrated to facilitate liver metabolic status to peripheral organs, such as adipose tissue.

Authors: Fritzi Ott, Christiane Körner, Kim Werner, Martin Gericke, Ines Liebscher, Donald Lobsien, Silvia Radrezza, Andrej Shevchenko, Ute Hofmann, Jürgen Kratzsch, Rolf Gebhardt, Thomas Berg, Madlen Matz-Soja

Date Published: 1st May 2022

Publication Type: Journal

Abstract (Expand)

Mouse models of non-alcoholic fatty liver disease (NAFLD) are required to define therapeutic targets, but detailed time-resolved studies to establish a sequence of events are lacking. Here, we fed malee, we fed male C57Bl/6N mice a Western or standard diet over 48 weeks. Multiscale time-resolved characterization was performed using RNA-seq, histopathology, immunohistochemistry, intravital imaging, and blood chemistry; the results were compared to human disease. Acetaminophen toxicity and ammonia metabolism were additionally analyzed as functional readouts. We identified a sequence of eight key events: formation of lipid droplets; inflammatory foci; lipogranulomas; zonal reorganization; cell death and replacement proliferation; ductular reaction; fibrogenesis; and hepatocellular cancer. Functional changes included resistance to acetaminophen and altered nitrogen metabolism. The transcriptomic landscape was characterized by two large clusters of monotonously increasing or decreasing genes, and a smaller number of ‘rest-and-jump genes’ that initially remained unaltered but became differentially expressed only at week 12 or later. Approximately 30% of the genes altered in human NAFLD are also altered in the present mouse model and an increasing overlap with genes altered in human HCC occurred at weeks 30–48. In conclusion, the observed sequence of events recapitulates many features of human disease and offers a basis for the identification of therapeutic targets.

Authors: Ahmed Ghallab, Maiju Myllys, Adrian Friebel, Julia Duda, Karolina Edlund, Emina Halilbasic, Mihael Vucur, Zaynab Hobloss, Lisa Brackhagen, Brigitte Begher-Tibbe, Reham Hassan, Michael Burke, Erhan Genc, Lynn Johann Frohwein, Ute Hofmann, Christian H. Holland, Daniela González, Magdalena Keller, Abdel-latif Seddek, Tahany Abbas, Elsayed S. I. Mohammed, Andreas Teufel, Timo Itzel, Sarah Metzler, Rosemarie Marchan, Cristina Cadenas, Carsten Watzl, Michael A. Nitsche, Franziska Kappenberg, Tom Luedde, Thomas Longerich, Jörg Rahnenführer, Stefan Hoehme, Michael Trauner, Jan G. Hengstler

Date Published: 1st Oct 2021

Publication Type: Journal

Abstract

Not specified

Authors: Christian H. Holland, Ricardo O. Ramirez Flores, Maiju Myllys, Reham Hassan, Karolina Edlund, Ute Hofmann, Rosemarie Marchan, Cristina Cadenas, Jörg Reinders, Stefan Hoehme, Abdel‐latif Seddek, Steven Dooley, Verena Keitel, Patricio Godoy, Brigitte Begher‐Tibbe, Christian Trautwein, Christian Rupp, Sebastian Mueller, Thomas Longerich, Jan G. Hengstler, Julio Saez‐Rodriguez, Ahmed Ghallab

Date Published: 28th Aug 2021

Publication Type: Journal

Abstract (Expand)

BACKGROUND: The extracellular signal-regulated kinase (ERK) pathway regulates cell growth, and is hyper-activated and associated with drug resistance in hepatocellular carcinoma (HCC). Metabolic pathways are profoundly dysregulated in HCC. Whether an altered metabolic state is linked to activated ERK pathway and drug response in HCC is unaddressed. METHODS: We deprived HCC cells of glutamine to induce metabolic alterations and performed various assays, including metabolomics (with (13)C-glucose isotope tracing), microarray analysis, and cell proliferation assays. Glutamine-deprived cells were also treated with kinase inhibitors (e.g. Sorafenib, Erlotinib, U0126 amongst other MEK inhibitors). We performed bioinformatics analysis and stratification of HCC tumour microarrays to determine upregulated ERK gene signatures in patients. FINDINGS: In a subset of HCC cells, the withdrawal of glutamine triggers a severe metabolic alteration and ERK phosphorylation (pERK). This is accompanied by resistance to the anti-proliferative effect of kinase inhibitors, despite pERK inhibition. High intracellular serine is a consistent feature of an altered metabolic state and contributes to pERK induction and the kinase inhibitor resistance. Blocking the ERK pathway facilitates cell proliferation by reprogramming metabolism, notably enhancing aerobic glycolysis. We have identified 24 highly expressed ERK gene signatures that their combined expression strongly indicates a dysregulated metabolic gene network in human HCC tissues. INTERPRETATION: A severely compromised metabolism lead to ERK pathway induction, and primes some HCC cells to pro-survival phenotypes upon ERK pathway blockade. Our findings offer novel insights for understanding, predicting and overcoming drug resistance in liver cancer patients. FUND: DFG, BMBF and Sino-German Cooperation Project.

Authors: Z. C. Nwosu, W. Pioronska, N. Battello, A. D. Zimmer, B. Dewidar, M. Han, S. Pereira, B. Blagojevic, D. Castven, V. Charlestin, P. Holenya, J. Lochead, C. De La Torre, N. Gretz, P. Sajjakulnukit, L. Zhang, M. H. Ward, J. U. Marquardt, M. P. di Magliano, C. A. Lyssiotis, J. Sleeman, S. Wolfl, M. P. Ebert, C. Meyer, U. Hofmann, S. Dooley

Date Published: 25th Apr 2020

Publication Type: Not specified

Abstract (Expand)

The Hedgehog (Hh) and Wnt/β-Catenin (Wnt) cascades are morphogen pathways whose pronounced influence on adult liver metabolism has been identified in recent years. How both pathways communicate and control liver metabolic functions are largely unknown. Detecting core components of Wnt and Hh signaling and mathematical modeling showed that both pathways in healthy liver act largely complementary to each other in the pericentral (Wnt) and the periportal zone (Hh) and communicate mainly by mutual repression. The Wnt/Hh module inversely controls the spatiotemporal operation of various liver metabolic pathways, as revealed by transcriptome, proteome, and metabolome analyses. Shifting the balance to Wnt (activation) or Hh (inhibition) causes pericentralization and periportalization of liver functions, respectively. Thus, homeostasis of the Wnt/Hh module is essential for maintaining proper liver metabolism and to avoid the development of certain metabolic diseases. With caution due to minor species-specific differences, these conclusions may hold for human liver as well.

Authors: Erik Kolbe, Susanne Aleithe, Christiane Rennert, Luise Spormann, Fritzi Ott, David Meierhofer, Robert Gajowski, Claus Stöpel, Stefan Hoehme, Michael Kücken, Lutz Brusch, Michael Seifert, Witigo von Schoenfels, Clemens Schafmayer, Mario Brosch, Ute Hofmann, Georg Damm, Daniel Seehofer, Jochen Hampe, Rolf Gebhardt, Madlen Matz-Soja

Date Published: 1st Dec 2019

Publication Type: Not specified

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