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385 Publications visible to you, out of a total of 385

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BACKGROUND AND AIMS: Little is known about genetic factors that affect development of alcohol-related cirrhosis. We performed a genome-wide association study (GWAS) of samples from the United Kingdom Biobank (UKB) to identify polymorphisms associated with risk of alcohol-related liver disease. METHODS: We performed a GWAS of 35,839 participants in the UKB with high intake of alcohol against markers of hepatic fibrosis (FIB-4, APRI, and Forns index scores) and hepatocellular injury (levels of aminotransferases). Loci identified in the discovery analysis were tested for their association with alcohol-related cirrhosis in 3 separate European cohorts (phase 1 validation cohort; n=2545). Variants associated with alcohol-related cirrhosis in the validation at a false discovery rate of less than 20% were then directly genotyped in 2 additional European validation cohorts (phase 2 validation, n=2068). RESULTS: In the GWAS of the discovery cohort, we identified 50 independent risk loci with genome-wide significance (P < 5 x 10(-8)). Nine of these loci were significantly associated with alcohol-related cirrhosis in the phase 1 validation cohort; 6 of these 9 loci were significantly associated with alcohol-related cirrhosis in phase 2 validation cohort, at a false discovery rate below 5%. The loci included variants in the mitochondrial amidoxime reducing component 1 gene (MARC1) and the heterogeneous nuclear ribonucleoprotein U like 1 gene (HNRNPUL1). After we adjusted for age, sex, body mass index, and type-2 diabetes in the phase 2 validation cohort, the minor A allele of MARC1:rs2642438 was associated with reduced risk of alcohol-related cirrhosis (adjusted odds ratio, 0.76; P=.0027); conversely, the minor C allele of HNRNPUL1:rs15052 was associated with an increased risk of alcohol-related cirrhosis (adjusted odds ratio, 1.30; P=.020). CONCLUSIONS: In a GWAS of samples from the UKB, we identified and validated (in 5 European cohorts) single-nucleotide polymorphisms that affect risk of alcohol-related cirrhosis in opposite directions: the minor A allele in MARC1:rs2642438 decreases risk, whereas the minor C allele in HNRNPUL1:rs15052 increases risk.

Authors: H. Innes, S. Buch, S. Hutchinson, I. N. Guha, J. R. Morling, E. Barnes, W. Irving, E. Forrest, V. Pedergnan, D. Goldberg, E. Aspinall, S. Barclay, P. Hayes, J. Dillon, H. D. Nischalke, P. Lutz, U. Spengler, J. Fischer, T. Berg, M. Brosch, F. Eyer, C. Datz, S. Mueller, T. Peccerella, P. Deltenre, A. Marot, M. Soyka, A. McQuillin, M. Y. Morgan, J. Hampe, F. Stickel

Date Published: 16th Jun 2020

Publication Type: Journal

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PK-DB is a database and web interface for pharmacokinetics data and information from clinical trials as well as pre-clinical research. PK-DB allows to curate pharmacokinetics data integrated with the corresponding meta-information. PK-DB is available at https://pk-db.com

Authors: Matthias König, Jan Grzegorzewski

Date Published: 1st Jun 2020

Publication Type: Misc

Abstract

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Authors: Stefan Hoehme, Rolf Gebhardt, JG Hengstler, D. Drasdo

Date Published: 18th May 2020

Publication Type: Misc

Abstract

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Authors: Adrian Friebel, Tim Johann, Dirk Drasdo, Stefan Hoehme

Date Published: 18th May 2020

Publication Type: Misc

Abstract

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Authors: Bjoern Goldenbogen, Stephan O. Adler, Oliver Bodeit, Judith AH Wodke, Aviv Korman, Lasse Bonn, Ximena Martinez de la Escalera, Johanna E L Haffner, Maria Krantz, Maxim Karnetzki, Ivo Maintz, Lisa Mallis, Rafael U Moran Torres, Hannah Prawitz, Patrick Segelitz, Martin Seeger, Rune Linding, Edda Klipp

Date Published: 6th May 2020

Publication Type: Unpublished

Abstract (Expand)

Lipid-based RNA nanocarriers have been recently accepted as a novel therapeutic option in humans, thus increasing the therapeutic options for patients. Tailored nanomedicines will enable to treat chronic liver disease (CLD) and end-stage liver cancer, disorders with high mortality and few treatment options. Here, we investigated the curative potential of gene therapy of a key molecule in CLD, the c-Jun N-terminal kinase-2 (Jnk2). Delivery to hepatocytes was achieved using a lipid-based clinically employable siRNA formulation that includes a cationic aminolipid to knockdown Jnk2 (named siJnk2). After assessing the therapeutic potential of siJnk2 treatment, non-invasive imaging demonstrated reduced apoptotic cell death and improved hepatocarcinogenesis was evidenced by improved liver parenchyma as well as ameliorated markers of hepatic damage, reduced fibrogenesis in 1-year-old mice. Strikingly, chronic siJnk2 treatment reduced premalignant nodules, indicative of tumor initiation. Furthermore, siJnk2 treatment led to a significant activation of the immune cell compartment. In conclusion, Jnk2 knockdown in hepatocytes ameliorated hepatitis, fibrogenesis, and initiation of hepatocellular carcinoma (HCC), and hence might be a suitable therapeutic option, to define novel molecular targets for precision medicine in CLD.

Authors: Marius Maximilian Woitok, Miguel Eugenio Zoubek, Dennis Doleschel, Matthias Bartneck, Mohamed Ramadan Mohamed, Fabian Kießling, Wiltrud Lederle, Christian Trautwein, Francisco Javier Cubero

Date Published: 1st May 2020

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)

How epithelial cells coordinate their polarity to form functional tissues is an open question in cell biology. Here, we characterize a unique type of polarity found in liver tissue, nematic cell polarity, which is different from vectorial cell polarity in simple, sheet-like epithelia. We propose a conceptual and algorithmic framework to characterize complex patterns of polarity proteins on the surface of a cell in terms of a multipole expansion. To rigorously quantify previously observed tissue-level patterns of nematic cell polarity (Morales-Navarette et al., eLife 8:e44860, 2019), we introduce the concept of co-orientational order parameters, which generalize the known biaxial order parameters of the theory of liquid crystals. Applying these concepts to three-dimensional reconstructions of single cells from high-resolution imaging data of mouse liver tissue, we show that the axes of nematic cell polarity of hepatocytes exhibit local coordination and are aligned with the biaxially anisotropic sinusoidal network for blood transport. Our study characterizes liver tissue as a biological example of a biaxial liquid crystal. The general methodology developed here could be applied to other tissues or in-vitro organoids.

Authors: Andre Scholich, Simon Syga, Hernan Morales-Navarrete, Fabian Segovia Miranda, Hidenori Nonaka, Kirstin Meyer, Walter de Back, Lutz Brusch, Yannis Kalaidzidis, Marino Zerial, Frank Julicher, Benjamin M. Friedrich

Date Published: 22nd Apr 2020

Publication Type: Not specified

Abstract (Expand)

BACKGROUND & AIMS: Zone-dependent differences in the expression of metabolic enzymes along the porto-central axis of the acinus are a long-known feature of liver metabolism. A prominent example is the preferential localization of the enzyme glutamine synthetase in pericentral hepatocytes, where it converts potentially toxic ammonia to the valuable amino acid glutamine. However, with the exception of a few key regulatory enzymes, a comprehensive and quantitative assessment of zonal differences in the abundance of metabolic enzymes and much more importantly, an estimation of the associated functional differences between portal and central hepatocytes is missing thus far. APPROACH & RESULTS: We addressed this problem by establishing a new method for the separation of periportal and pericentral hepatocytes that yields sufficiently pure fractions of both cell populations. Quantitative shotgun proteomics identified hundreds of differentially expressed enzymes in the two cell populations. We used zone-specific proteomics data for scaling of the maximal activities to generate portal and central instantiations of a comprehensive kinetic model of central hepatic metabolism (Hepatokin1). CONCLUSION: The model simulations revealed significant portal-to-central differences in almost all metabolic pathways involving carbohydrates, fatty acids, amino acids and detoxification.

Authors: N. Berndt, E. Kolbe, R. Gajowski, J. Eckstein, F. Ott, D. Meierhofer, H. G. Holzhutter, M. Matz-Soja

Date Published: 14th Apr 2020

Publication Type: Not specified

Abstract (Expand)

Protein modification with ISG15 (ISGylation) represents a major type I IFN-induced antimicrobial system. Common mechanisms of action and species-specific aspects of ISGylation, however, are still ill defined and controversial. We used a multiphasic coxsackievirus B3 (CV) infection model with a first wave resulting in hepatic injury of the liver, followed by a second wave culminating in cardiac damage. This study shows that ISGylation sets nonhematopoietic cells into a resistant state, being indispensable for CV control, which is accomplished by synergistic activity of ISG15 on antiviral IFIT1/3 proteins. Concurrent with altered energy demands, ISG15 also adapts liver metabolism during infection. Shotgun proteomics, in combination with metabolic network modeling, revealed that ISG15 increases the oxidative capacity and promotes gluconeogenesis in liver cells. Cells lacking the activity of the ISG15-specific protease USP18 exhibit increased resistance to clinically relevant CV strains, therefore suggesting that stabilizing ISGylation by inhibiting USP18 could be exploited for CV-associated human pathologies.

Authors: M. Kespohl, C. Bredow, K. Klingel, M. Voss, A. Paeschke, M. Zickler, W. Poller, Z. Kaya, J. Eckstein, H. Fechner, J. Spranger, M. Fahling, E. K. Wirth, L. Radoshevich, F. Thery, F. Impens, N. Berndt, K. P. Knobeloch, A. Beling

Date Published: 21st Mar 2020

Publication Type: Not specified

Abstract (Expand)

Maintenance of tissue extracellular matrix (ECM) and its biomechanical properties for tissue engineering is one of the substantial challenges in the field of decellularization and recellularization. Preservation of the organ-specific biomatrix is crucial for successful recellularization to support cell survival, proliferation, and functionality. However, understanding ECM properties with and without its inhabiting cells as well as the transition between the two states lacks appropriate test methods capable of quantifying bulk viscoelastic parameters in soft tissues. We used compact magnetic resonance elastography (MRE) with 400, 500, and 600 Hz driving frequency to investigate rat liver specimens for quantification of viscoelastic property changes resulting from decellularization. Tissue structures in native and decellularized livers were characterized by collagen and elastin quantification, histological analysis, and scanning electron microscopy. Decellularization did not affect the integrity of microanatomy and structural composition of liver ECM but was found to be associated with increases in the relative amounts of collagen by 83-fold (37.4 +/- 17.5 vs. 0.5 +/- 0.01 mug/mg, p = 0.0002) and elastin by approx. 3-fold (404.1 +/- 139.6 vs. 151.0 +/- 132.3 mug/mg, p = 0.0046). Decellularization reduced storage modulus by approx. 9-fold (from 4.9 +/- 0.8 kPa to 0.5 +/- 0.5 kPa, p < 0.0001) and loss modulus by approx. 7-fold (3.6 kPa to 0.5 kPa, p < 0.0001), indicating a marked loss of global tissue rigidity as well as a property shift from solid towards more fluid tissue behavior (p = 0.0097). Our results suggest that the rigidity of liver tissue is largely determined by cellular components, which are replaced by fluid-filled spaces when cells are removed. This leads to an overall increase in tissue fluidity and a viscous drag within the relatively sparse remaining ECM. Compact MRE is an excellent tool for quantifying the mechanical properties of decellularized biological tissue and a promising candidate for useful applications in tissue engineering.

Authors: H. Everwien, A. Ariza de Schellenberger, N. Haep, H. Tzschatzsch, J. Pratschke, I. M. Sauer, J. Braun, K. H. Hillebrandt, I. Sack

Date Published: 17th Mar 2020

Publication Type: Not specified

Abstract

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Authors: C. Lieven, M. E. Beber, B. G. Olivier, F. T. Bergmann, M. Ataman, P. Babaei, J. A. Bartell, L. M. Blank, S. Chauhan, K. Correia, C. Diener, A. Drager, B. E. Ebert, J. N. Edirisinghe, J. P. Faria, A. M. Feist, G. Fengos, R. M. T. Fleming, B. Garcia-Jimenez, V. Hatzimanikatis, W. van Helvoirt, C. S. Henry, H. Hermjakob, M. J. Herrgard, A. Kaafarani, H. U. Kim, Z. King, S. Klamt, E. Klipp, J. J. Koehorst, M. Konig, M. Lakshmanan, D. Y. Lee, S. Y. Lee, S. Lee, N. E. Lewis, F. Liu, H. Ma, D. Machado, R. Mahadevan, P. Maia, A. Mardinoglu, G. L. Medlock, J. M. Monk, J. Nielsen, L. K. Nielsen, J. Nogales, I. Nookaew, B. O. Palsson, J. A. Papin, K. R. Patil, M. Poolman, N. D. Price, O. Resendis-Antonio, A. Richelle, I. Rocha, B. J. Sanchez, P. J. Schaap, R. S. Malik Sheriff, S. Shoaie, N. Sonnenschein, B. Teusink, P. Vilaca, J. O. Vik, J. A. H. Wodke, J. C. Xavier, Q. Yuan, M. Zakhartsev, C. Zhang

Date Published: 4th Mar 2020

Publication Type: Journal

Abstract

sbmlutils is a collection of python utilities for working with SBML models implemented on top of libSBML and other libraries available from https://github.com/matthiaskoenig/sbmlutils

Author: Matthias König

Date Published: 1st Mar 2020

Publication Type: Misc

Abstract (Expand)

The mechanisms of organ size control remain poorly understood. A key question is how cells collectively sense the overall status of a tissue. We addressed this problem focusing on mouse liver regeneration. Using digital tissue reconstruction and quantitative image analysis, we found that the apical surface of hepatocytes forming the bile canalicular network expands concomitant with an increase in F-actin and phospho-myosin, to compensate an overload of bile acids. These changes are sensed by the Hippo transcriptional co-activator YAP, which localizes to apical F-actin-rich regions and translocates to the nucleus in dependence of the integrity of the actin cytoskeleton. This mechanism tolerates moderate bile acid fluctuations under tissue homeostasis, but activates YAP in response to sustained bile acid overload. Using an integrated biophysical-biochemical model of bile pressure and Hippo signaling, we explained this behavior by the existence of a mechano-sensory mechanism that activates YAP in a switch-like manner. We propose that the apical surface of hepatocytes acts as a self-regulatory mechano-sensory system that responds to critical levels of bile acids as readout of tissue status.

Authors: K. Meyer, H. Morales-Navarrete, S. Seifert, M. Wilsch-Braeuninger, U. Dahmen, E. M. Tanaka, L. Brusch, Y. Kalaidzidis, M. Zerial

Date Published: 25th Feb 2020

Publication Type: Journal

Abstract (Expand)

The mechanisms of organ size control remain poorly understood. A key question is how cells collectively sense the overall status of a tissue. We addressed this problem focusing on mouse liver regeneration. Using digital tissue reconstruction and quantitative image analysis, we found that the apical surface of hepatocytes forming the bile canalicular network expands concomitant with an increase in F‐actin and phospho‐myosin, to compensate an overload of bile acids. These changes are sensed by the Hippo transcriptional co‐activator YAP, which localizes to apical F‐actin‐rich regions and translocates to the nucleus in dependence of the integrity of the actin cytoskeleton. This mechanism tolerates moderate bile acid fluctuations under tissue homeostasis, but activates YAP in response to sustained bile acid overload. Using an integrated biophysical–biochemical model of bile pressure and Hippo signaling, we explained this behavior by the existence of a mechano‐sensory mechanism that activates YAP in a switch‐like manner. We propose that the apical surface of hepatocytes acts as a self‐regulatory mechano‐sensory system that responds to critical levels of bile acids as readout of tissue status.

Authors: Kirstin Meyer, Hernan Morales‐Navarrete, Sarah Seifert, Michaela Wilsch‐Braeuninger, Uta Dahmen, Elly M Tanaka, Lutz Brusch, Yannis Kalaidzidis, Marino Zerial

Date Published: 24th Feb 2020

Publication Type: Not specified

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