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Authors: Yoon Seok Jung, Kamalakannan Radhakrishnan, Seddik Hammad, Sebastian Müller, Johannes Müller, Jung-Ran Noh, Jina kim, In-Kyu Lee, Sung Jin Cho, Don-Kyu Kim, Yong-Hoon Kim, Chul-Ho Lee, Steven Dooley, Hueng-Sik Choi

Date Published: 1st Mar 2024

Publication Type: Journal

Abstract (Expand)

Prerequisite for a successful proteomics experiment is a high-quality lysis of the sample of interest, resulting in a large number of identified proteins as well as a high coverage of protein sequences. Therefore, the choice of suitable lysis conditions is crucial. Many buffers were previously employed in proteomics studies, yet a comprehensive comparison of lysate preparation conditions was so far missing. In this study, we compared the efficiency of four commonly used lysis buffers, containing the agents NP40, SDS, urea or GdnHCl, in four different types of biological samples (suspension and adherent cell lines, primary mouse cells and mouse liver tissue). After liquid chromatography-mass spectrometry (LC-MS) measurement and MaxQuant analysis, we compared chromatograms, intensities, number of identified proteins and the localization of the identified proteins. Overall, SDS emerged as the most reliable reagent, ensuring stable performance and reproducibility across diverse samples. Furthermore, our data advocated for a dual-sample lysis approach, including that the resulting pellet is lysed again after the initial lysis with a urea lysis buffer and subsequently both lysates are combined for a single LC-MS run to maximize the proteome coverage. However, none of the investigated lysis buffers proved to be superior in every category, indicating that the lysis buffer of choice depends on the proteins of interest and on the biological question. Further, we demonstrated with our systematic studies the establishment of conditions that allows to perform global proteomics and affinity purification-based interactome characterization from the same lysate. In sum our results provide guidance for the best-suited lysis buffer for mass spectrometry-based proteomics depending on the question of interest.

Authors: Barbara Helm, Pauline Hansen, Li Lai, Luisa Schwarzmüller, Simone M. Clas, Annika Richter, Max Ruwolt, Fan Liu, Dario Frey, Lorenza A. D’Alessandro, Wolf-Dieter Lehmann, Marcel Schilling, Dominic Helm, Dorothea Fiedler, Ursula Klingmüller

Date Published: 21st Feb 2024

Publication Type: Journal

Abstract (Expand)

Objective In healthy livers, latent transforming growth factor-β (LTGF-β) is stored in the extracellular matrix and kept quiescent by extracellular matrix protein 1 (ECM1). Upon damage, ECM1 isage, ECM1 is downregulated in hepatocytes, facilitating LTGF-β activation and hepatic fibrosis. This study investigates the underlying molecular mechanisms by which ECM1 expression in the liver is controlled under patho-physiological conditions. Design In silico promoter analysis was used to predict pathways that regulate Ecm1 transcription. Functional assays were performed in AML12 cells, mouse and human primary hepatocytes (MPHs, HPHs), and in liver tissue of mice and patients. Results In healthy liver, EGF/Egfr signaling maintains Ecm1 expression through phosphorylation of Stat1 at S727, which promotes its binding to the Ecm1 gene promoter to enhance gene transcription. During liver inflammation, accumulated IFNγ interferes with EGF signaling by downregulating Egfr expression and by disrupting EGF/Egfr/Stat1-mediated Ecm1 promoter binding. Mechanistically, IFNγ induces Stat1 phosphorylation at position Y701, which is competing with the ability of p-Stat1 S727 to bind to the Ecm1 gene promoter. Additionally, IFNγ induces Nrf2 nuclear translocation and repressive binding to the Ecm1 gene promoter, thus further reducing Ecm1 expression. Importantly, patients suffering from liver cirrhosis who lack nuclear NRF2 expression consistently maintain higher levels of ECM1, inferring a better prognosis. Conclusion ECM1 expression in healthy livers is controlled by EGF/EGFR/STAT1 signaling. Upon liver injury, ECM1 expression is repressed by accumulating IFNγ/NRF2, leading to increased LTGF-β activation and the onset of hepatic fibrosis.

Authors: Yujia Li, Frederik Link, Weiguo Fan, Zeribe C. Nwosu, Weronika Pioronska, Kerry Gould, Christoph Meyer, Ye Yao, Seddik Hammad, Rilu Feng, Hui Liu, Chen Shao, Bing Sun, Huiguo Ding, Roman Liebe, Matthias P. A. Ebert, Hong-Lei Weng, Peter ten Dijke, Steven Dooley, Sai Wang

Date Published: 19th Feb 2024

Publication Type: Journal

Abstract (Expand)

Abstract Transforming growth factor (TGF)‐β and toll‐like receptors (TLRs) have been shown to independently modulate the proliferation of hepatocellular carcinoma (HCC). Since a direct cross‐talk between (HCC). Since a direct cross‐talk between these two signalling pathways in HCC has not been clearly described before, we aimed here to explore the possibility of such interaction. A human HCC tissue array ( n  = 20 vs. four control samples), human HCC samples ( n  = 10) and steatohepatitis‐driven murine HCC samples (control, NASH and HCC; n  = 6/group) were immunostained for TGFβR1, pSMAD2, TRAF6, IRAK1 and PCNA. The results were confirmed by immunoblotting. Effects of constant activation of the SMAD pathway by constitutive expression of ALK5 or knockdown of mediators of TLR signalling, IRAK1 and MyD88, on HCC proliferation, were investigated in the HCC cell line (HUH‐7) after treatment with TGFβ1 cytokine or TGFβR1 kinase inhibitor (LY2157299) using PCNA and MTS assay. TGFβR1 expression is decreased in human and murine HCC and associated with downregulated pSMAD2, but increased IRAK1, TRAF6 and PCNA staining. TGFβR1 kinase inhibition abolished the cytostatic effects of TGFβ1 and led to the induction of IRAK1, pIRAK1 and elevated mRNA levels of TLR‐9. Overexpression of ALK5 and knockdown of MyD88 or IRAK1 augmented the cytostatic effects of TGFβ1 on HUH‐7. In another epithelial HCC cell line, that is, HepG2, TGFβR1 kinase inhibitor similarly elevated cellular proliferation. There is a balance between the canonical SMAD‐driven tumour‐suppressing arm and the non‐canonical tumour‐promoting arm of TGFβ signalling. Disruption of this balance, by inhibition of the canonical pathway, induces HCC proliferation through TLR signalling.

Authors: Fatma El Zahraa Ammar Mohamed, Bedair Dewidar, Tao Lin, Matthias P. Ebert, Steven Dooley, Nadja M. Meindl‐Beinker, Seddik Hammad

Date Published: 8th Feb 2024

Publication Type: Journal

Abstract (Expand)

Abstract The extracellular environment regulates the structures and functions of cells, from the molecular to the tissue level. However, the underlying mechanisms influencing the organization andncing the organization and adaptation of cancer in three‐dimensional (3D) environments are not yet fully understood. In this study, the influence of the viscosity of the environment is investigated on the mechanical adaptability of human hepatoma cell (HepG2) spheroids in vitro, using 3D microcapsule reactors formed with droplet‐based microfluidics. To mimic the environment with different mechanical properties, HepG2 cells are encapsulated in alginate core–shell reservoirs (i.e., microcapsules) with different core viscosities tuned by incorporating carboxymethylcellulose. The significant changes in cell and spheroid distribution, proliferation, and cytoskeleton are observed and quantified. Importantly, changes in the expression and distribution of F‐actin and keratin 8 indicate the relation between spheroid stiffness and viscosity of the surrounding medium. The increase of F‐actin levels in the viscous medium can indicate an enhanced ability of tumor cells to traverse dense tissue. These results demonstrate the ability of cancer cells to dynamically adapt to the changes in extracellular viscosity, which is an important physical cue regulating tumor development, and thus of relevance in cancer biology.

Authors: Xuan Peng, Željko Janićijević, Sandy Lemm, Sandra Hauser, Michael Knobel, Jens Pietzsch, Michael Bachmann, Larysa Baraban

Date Published: 25th Jan 2024

Publication Type: Journal

Abstract (Expand)

Abstract Chronic liver diseases are worldwide on the rise. Due to the rapidly increasing incidence, in particular in Western countries, metabolic dysfunction-associated steatotic liver disease (MASLD)otic liver disease (MASLD) is gaining importance as the disease can develop into hepatocellular carcinoma. Lipid accumulation in hepatocytes has been identified as the characteristic structural change in MASLD development, but molecular mechanisms responsible for disease progression remained unresolved. Here, we uncover in primary hepatocytes from a preclinical model fed with a Western diet (WD) an increased basal MET phosphorylation and a strong downregulation of the PI3K-AKT pathway. Dynamic pathway modeling of hepatocyte growth factor (HGF) signal transduction combined with global proteomics identifies that an elevated basal MET phosphorylation rate is the main driver of altered signaling leading to increased proliferation of WD-hepatocytes. Model-adaptation to patient-derived hepatocytes reveal patient-specific variability in basal MET phosphorylation, which correlates with patient outcome after liver surgery. Thus, dysregulated basal MET phosphorylation could be an indicator for the health status of the liver and thereby inform on the risk of a patient to suffer from liver failure after surgery.

Authors: Sebastian Burbano de Lara, Svenja Kemmer, Ina Biermayer, Svenja Feiler, Artyom Vlasov, Lorenza A D’Alessandro, Barbara Helm, Christina Mölders, Yannik Dieter, Ahmed Ghallab, Jan G Hengstler, Christiane Körner, Madlen Matz-Soja, Christina Götz, Georg Damm, Katrin Hoffmann, Daniel Seehofer, Thomas Berg, Marcel Schilling, Jens Timmer, Ursula Klingmüller

Date Published: 12th Jan 2024

Publication Type: Journal

Abstract

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Authors: Frederik Link, Yujia Li, Jieling Zhao, Stefan Munker, Weiguo Fan, Zeribe Nwosu, Ye Yao, Seddik Hammad, Roman Liebe, Peter ten Dijke, Honglei Weng, Matthias Ebert, Drik Drasdo, Steven Dooley, Sai Wang

Date Published: 2024

Publication Type: Journal

Abstract

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Authors: Sai Wang, Frederik Link, Mei Han, Roohi Chaudhary, Anastasia Asimakopoulos, Roman Liebe, Ye Yao, Seddik Hammad, Anne Dropmann, Marinela Krizanac, Matthias Ebert, Ralf Weiskirchen, Yoav I. Henis, Marcelo Ehrlich, Steven Dooley

Date Published: 2024

Publication Type: InProceedings

Abstract

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Authors: Sai Wang, Frederik Link, Mei Han, Roohi Chaudhary, Anastasia Asimakopoulos, Roman Liebe, Ye Yao, Seddik Hammad, Anne Dropmann, Marinela Krizanac, Claudia Rubie, Laura Kim Feiner, Matthias Glanemann, Matthias P.A. Ebert, Ralf Weiskirchen, Yoav I. Henis, Marcelo Ehrlich, Steven Dooley

Date Published: 2024

Publication Type: Journal

Abstract (Expand)

Abstract Objective Extracellular Matrix Protein 1 ( Ecm1 ) knockout results in latent transforming growth factor-β1 (LTGF-β1) activation and hepatic fibrosis with rapid mortality in mice. In chronicctor-β1 (LTGF-β1) activation and hepatic fibrosis with rapid mortality in mice. In chronic liver disease (CLD), ECM1 is gradually lost with increasing CLD severity. We investigated the underlying mechanism and its impact on CLD progression. Design RNAseq was performed to analyze gene expression in the liver. Functional assays were performed using hepatic stellate cells (HSCs), WT and Ecm1 -KO mice, and liver tissue. Computer modeling was used to verify experimental findings. Results RNAseq shows that expression of thrombospondins (TSPs), ADAMTS proteases, and matrix metalloproteinases (MMPs) increases along with TGF-β1 target, pro-fibrotic genes in liver tissue of Ecm1 -KO mice. In LX-2 or primary human HSCs, ECM1 prevented TSP-1-, ADAMTS1-, and MMP-2/9-mediated LTGF-β1 activation. I n vitro interaction assays demonstrated that ECM1 inhibited LTGF-β1 activation through interacting with TSP-1 and ADAMTS1 via their respective, intrinsic KRFK or KTFR amino acid sequences, while also blunting MMP-2/9 proteolytic activity. In mice, AAV8-mediated ECM1 overexpression attenuated KRFK-induced LTGF-β1 activation and fibrosis, while KTFR reversed Ecm1 -KO-induced liver injury. Furthermore, a correlation between decreasing ECM1 and increasing protease expression and LTGF-β1 activation was found in CLD patients. A computational model validated the impact of restoring ECM1 on reducing LTGF-β1 activation, HSC activation, and collagen deposition in the liver. Conclusion Our findings underscore the hepatoprotective effect of ECM1, which inhibits protease-mediated LTGF-β1 activation, suggesting that preventing its decrease or restoring ECM1 function in the liver could serve as a novel and safer than direct TGF-β1-directed therapies in CLD. One sentence summary ECM1 loss fails to prevent TSP/ADAMTS/MMP-mediated LTGF-β1 activation, leading to liver fibrosis progression.

Authors: Frederik Link, Yujia Li, Jieling Zhao, Stefan Munker, Weiguo Fan, Zeribe Nwosu, Ye Yao, Seddik Hammad, Roman Liebe, Hui Liu, Chen Shao, Bing Sun, Natalie J. Török, Huiguo Ding, Matthias P. A. Ebert, Hong-Lei Weng, Peter ten Dijke, Dirk Drasdo, Steven Dooley, Sai Wang

Date Published: 12th Dec 2023

Publication Type: Journal

Abstract (Expand)

Abstract Type I interferons (IFNs) play a central role not only in innate immunity against viral infection, but also in the antitumour response, e.g. through a direct impact on cell proliferation.act on cell proliferation. Particularly for cancer arising in the context of chronic inflammation, constant exposure to IFNs may constitute a strong selective pressure during tumour evolution. Expansion of neoplastic subclones resistant to the antiproliferative effects of IFNs may contribute to immunoediting of tumours, leading to more aggressive disease. Experimental evidence for this development of IFN-insensitivity has been scarce and its molecular mechanism is unclear. In this study we demonstrate that six weeks exposure of cells to IFN-β in vitro reduces their sensitivity to its antiproliferative effects, and that this phenotype was stable for up to four weeks. Furthermore, we observed substantial differences in cellular sensitivity to growth inhibition by IFN-β in a panel of ten different liver cancer cell lines, most prominently in a pair of highly dedifferentiated cell lines, and least in cells from well-differentiated tumours. In both, long-term IFN selection and in dedifferentiated tumour cell lines, we found IFNAR2 expression to be substantially reduced, suggesting the receptor complex to be a sensitive target amenable to immunoediting. Beyond new insights into possible molecular processes in tumour evolution, these findings might prove valuable for the development of biomarkers allowing to stratify tumours for their sensitivity to IFN treatment in the context of patient tailored therapies.

Authors: Felix Hiebinger, Aiste Kudulyte, Huanting Chi, Sebastian Burbano De Lara, Doroteja Ilic, Barbara Helm, Hendrik Welsch, Viet Loan Dao Thi, Ursula Klingmüller, Marco Binder

Date Published: 1st Dec 2023

Publication Type: Journal

Abstract (Expand)

Hepatitis C virus (HCV) infection can lead to hepatic fibrosis. The advent of direct-acting antivirals (DAAs) has substantially improved sustained virological response (SVR) rates. In this context, this context, kidney transplant recipients (KTRs) are of particular interest due to their higher HCV infection rates and uncertain renal excretion and bioavailability of DAAs. We investigated liver stiffness after DAA treatment in 15 HCV-infected KTRs using ultrasound shear wave elastography (SWE) in comparison with magnetic resonance elastography (MRE). KTRs were treated with DAAs (daclatasvir and sofosbuvir) for three months and underwent SWE at baseline, end of therapy (EOT), and 3 (EOT+3) and 12 months (EOT+12) after EOT. Fourteen patients achieved SVR12. Shear wave speed (SWS)—as a surrogate parameter for tissue stiffness—was substantially lower at all three post-therapeutic timepoints compared with baseline (EOT: −0.42 m/s, p < 0.01; CI = −0.75–−0.09, EOT+3: −0.43 m/s, p < 0.01; CI = −0.75–−0.11, and EOT+12: −0.52 m/s, p < 0.001; CI = −0.84–−0.19), suggesting liver regeneration after viral eradication and end of inflammation. Baseline SWS correlated positively with histopathological fibrosis scores (r = 0.48; CI = −0.11–0.85). Longitudinal results correlated moderately with APRI (r = 0.41; CI = 0.12–0.64) but not with FIB-4 scores (r = 0.12; CI = −0.19–0.41). Although higher on average, SWE-derived measurements correlated strongly with MRE (r = 0.64). In conclusion, SWE is suitable for non-invasive therapy monitoring in KTRs with HCV infection.

Authors: Salma Almutawakel, Fabian Halleck, Michael Dürr, Ulrike Grittner, Eva Schrezenmeier, Klemens Budde, Christian E. Althoff, Bernd Hamm, Ingolf Sack, Thomas Fischer, Stephan R. Marticorena Garcia

Date Published: 1st Dec 2023

Publication Type: Journal

Abstract (Expand)

Abstract Gene regulation plays a critical role in the cellular processes that underlie human health and disease. The regulatory relationship between transcription factors (TFs), key regulators of genes), key regulators of gene expression, and their target genes, the so called TF regulons, can be coupled with computational algorithms to estimate the activity of TFs. However, to interpret these findings accurately, regulons of high reliability and coverage are needed. In this study, we present and evaluate a collection of regulons created using the CollecTRI meta-resource containing signed TF–gene interactions for 1186 TFs. In this context, we introduce a workflow to integrate information from multiple resources and assign the sign of regulation to TF–gene interactions that could be applied to other comprehensive knowledge bases. We find that the signed CollecTRI-derived regulons outperform other public collections of regulatory interactions in accurately inferring changes in TF activities in perturbation experiments. Furthermore, we showcase the value of the regulons by examining TF activity profiles in three different cancer types and exploring TF activities at the level of single-cells. Overall, the CollecTRI-derived TF regulons enable the accurate and comprehensive estimation of TF activities and thereby help to interpret transcriptomics data.

Authors: Sophia Müller-Dott, Eirini Tsirvouli, Miguel Vazquez, Ricardo O Ramirez Flores, Pau Badia-i-Mompel, Robin Fallegger, Dénes Türei, Astrid Lægreid, Julio Saez-Rodriguez

Date Published: 10th Nov 2023

Publication Type: Journal

Abstract (Expand)

MOTIVATION: Biological tissues are dynamic and highly organized. Multi-scale models are helpful tools to analyse and understand the processes determining tissue dynamics. These models usually depend on parameters that need to be inferred from experimental data to achieve a quantitative understanding, to predict the response to perturbations, and to evaluate competing hypotheses. However, even advanced inference approaches such as approximate Bayesian computation (ABC) are difficult to apply due to the computational complexity of the simulation of multi-scale models. Thus, there is a need for a scalable pipeline for modeling, simulating, and parameterizing multi-scale models of multi-cellular processes. RESULTS: Here, we present FitMultiCell, a computationally efficient and user-friendly open-source pipeline that can handle the full workflow of modeling, simulating, and parameterizing for multi-scale models of multi-cellular processes. The pipeline is modular and integrates the modeling and simulation tool Morpheus and the statistical inference tool pyABC. The easy integration of high-performance infrastructure allows to scale to computationally expensive problems. The introduction of a novel standard for the formulation of parameter inference problems for multi-scale models additionally ensures reproducibility and reusability. By applying the pipeline to multiple biological problems, we demonstrate its broad applicability, which will benefit in particular image-based systems biology. AVAILABILITY AND IMPLEMENTATION: FitMultiCell is available open-source at https://gitlab.com/fitmulticell/fit.

Authors: E. Alamoudi, Y. Schalte, R. Muller, J. Starruss, N. Bundgaard, F. Graw, L. Brusch, J. Hasenauer

Date Published: 1st Nov 2023

Publication Type: Journal

Abstract (Expand)

Loss of hepatocyte nuclear factor 4α (HNF4α) expression is frequently observed in end-stage liver disease and associated with loss of vital liver functions, thus increasjng mortality. Loss of HNF4α expression is mediated by inflammatory cytokines, such as transforming growth factor (TGF)-β. However, details of how HNF4α is suppressed are largely unknown to date. This study reports that TGF-β does not directly inhibit HNF4α but contributes to its transcriptional regulation by SMAD2/3 recruiting acetyltransferase CREB-binding protein/p300 to the HNF4α promoter. The recruitment of CREB-binding protein/p300 is indispensable for CCAAT/enhancer-binding protein α (C/EBPα) binding, another essential requirement for constitutive HNF4α expression in hepatocytes. Consistent with the in vitro observation, 67 of 98 patients with hepatic HNF4α express both phospho-SMAD2 and C/EBPα, whereas 22 patients without HNF4α expression lack either phospho-SMAD2 or C/EBPα. In contrast to the observed induction of HNF4α, SMAD2/3 inhibits C/EBPα transcription. Therefore, long-term TGF-β incubation results in C/EBPα depletion, which abrogates HNF4α expression. Intriguingly, SMAD2/3 inhibitory binding to the C/EBPα promoter is abolished by insulin. Two-thirds of patients without C/EBPα lack membrane glucose transporter type 2 expression in hepatocytes, indicating insulin resistance. Taken together, hepatic insulin sensitivity is essential for hepatic HNF4α expression in the condition of inflammation.

Authors: Rilu Feng, Chenhao Tong, Tao Lin, Hui Liu, Chen Shao, Yujia Li, Carsten Sticht, Kejia Kan, Xiaofeng Li, Rui Liu, Sai Wang, Shanshan Wang, Stefan Munker, Hanno Niess, Christoph Meyer, Roman Liebe, Matthias P. Ebert, Steven Dooley, Hua Wang, Huiguo Ding, Hong-Lei Weng

Date Published: 1st Oct 2023

Publication Type: Journal

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