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81 Publications visible to you, out of a total of 81

Abstract

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Authors: Dilay Lai, Feng Teng, Seddik Hammad, Julia Werle, Thorsten Maas, Andreas Teufel, Martina U. Muckenthaler, Steven Dooley, Maja Vujić Spasić

Date Published: 1st Feb 2018

Publication Type: Not specified

Abstract (Expand)

Caveolin-1 (CAV1) is a crucial regulator of lipid accumulation and metabolism. Previous studies have shown that global Cav1 deficiency affects lipid metabolism and hepatic steatosis. We aimed to analyze the consequences of hepatocyte-specific Cav1 knockout under healthy conditions and upon non-alcoholic fatty liver disease (NAFLD) development. Male and female hepatocyte-specific Cav1 knockout (HepCAV1ko) mice were fed a methionine/choline (MCD) deficient diet for 4 weeks. MCD feeding caused severe hepatic steatosis and slight fibrosis. In addition, liver function parameters, i.e., ALT, AST, and GLDH, were elevated, while cholesterol and glucose level were reduced upon MCD feeding. These differences were not affected by hepatocyte-specific Cav1 knockout. Microarray analysis showed strong differences in gene expression profiles of livers from HepCAV1ko mice compared those of global Cav1 knockout animals. Pathway enrichment analysis identified that metabolic alterations were sex-dimorphically regulated by hepatocyte-specific CAV1. In male HepCAV1ko mice, metabolic pathways were suppressed in NAFLD, whereas in female knockout mice induced. Moreover, gender-specific transcription profiles were modulated in healthy animals. In conclusion, our results demonstrate that hepatocyte-specific Cav1 knockout significantly altered gene profiles, did not affect liver steatosis and fibrosis in NAFLD and that gender had severe impact on gene expression patterns in healthy and diseased hepatocyte-specific Cav1 knockout mice.

Authors: M. Han, W. Pioronska, S. Wang, Z. C. Nwosu, C. Sticht, S. Wang, Y. Gao, M. P. Ebert, S. Dooley, C. Meyer

Date Published: 6th Feb 2020

Publication Type: Journal

Abstract (Expand)

Background & Aims Inflammation in chronic liver diseases induces oxidative stress and thus may contribute to progression of liver injury, fibrosis, and carcinogenesis. The KEAP1/NRF2 axis is a major regulator of cellular redox balance. In the present study, we investigated whether the KEAP1/NRF2 system is involved in liver disease progression in human and mice. Methods The clinical relevance of oxidative stress was investigated in a well-characterized cohort of NAFLD patients (n=63) by liver RNA sequencing and correlated with histological and clinical parameters. For functional analysis hepatocyte-specific NEMO knock-out (NEMO Δhepa) mice were crossed with hepatocyte-specific KEAP1 knock-out (KEAP1 Δhepa) mice. Results Immunohistochemical analysis of human liver sections showed increased oxidative stress and high NRF2 expression in patients with chronic liver disease. RNA sequencing of liver samples in a human pediatric NAFLD cohort revealed a significant increase of NRF2 activation correlating with the grade of inflammation, but not with the grade of steatosis, which could be confirmed in a second adult NASH cohort. In mice, microarray analysis revealed that KEAP1 deletion induces NRF2 target genes involved in glutathione metabolism and xenobiotic stress (e.g., Nqo1). Furthermore, deficiency of one of the most important antioxidants, glutathione (GSH), in NEMO Δhepa livers was rescued after deleting KEAP1. As a consequence, NEMO Δhepa/KEAP1 Δhepa livers showed reduced apoptosis compared to NEMO Δhepa livers as well as a dramatic downregulation of genes involved in cell cycle regulation and DNA replication. Consequently, NEMO Δhepa/KEAP1 Δhepa compared to NEMO Δhepa livers displayed decreased fibrogenesis, lower tumor incidence, reduced tumor number, and decreased tumor size. Conclusions NRF2 activation in NASH patients correlates with the grade of inflammation, but not steatosis. Functional analysis in mice demonstrated that NRF2 activation in chronic liver disease is protective by ameliorating fibrogenesis, initiation and progression of hepatocellular carcinogenesis.

Authors: Antje Mohs, Tobias Otto, Kai Markus Schneider, Mona Peltzer, Mark Boekschoten, Christian H. Holland, Christian A. Hudert, Laura Kalveram, Susanna Wiegand, Julio Saez-Rodriguez, Thomas Longerich, Jan G. Hengstler, Christian Trautwein

Date Published: 1st Oct 2020

Publication Type: Journal

Abstract

Not specified

Authors: T Feng, J Dzieran, X Yuan, A Dropmann, T Maass, A Teufel, S Marhenke, T Gaiser, F Rückert, I Kleiter, S Kanzler, M P Ebert, A Vogel, P ten Dijke, S Dooley, N M Meindl-Beinker

Date Published: 2017

Publication Type: Not specified

Abstract (Expand)

Background: Macrophages play an important role in maintaining liver homeostasis and regeneration. However, it is not clear to what extent the different macrophage populations of the liver differ in terms of their activation state and which other liver cell populations may play a role in regulating the same. Methods: Reverse transcription PCR, flow cytometry, transcriptome, proteome, secretome, single cell analysis, and immunohistochemical methods were used to study changes in gene expression as well as the activation state of macrophages in vitro and in vivo under homeostatic conditions and after partial hepatectomy. Results: We show that F4/80+/CD11bhi/CD14hi macrophages of the liver are recruited in a C-C motif chemokine receptor (CCR2)–dependent manner and exhibit an activation state that differs substantially from that of the other liver macrophage populations, which can be distinguished on the basis of CD11b and CD14 expressions. Thereby, primary hepatocytes are capable of creating an environment in vitro that elicits the same specific activation state in bone marrow–derived macrophages as observed in F4/80+/CD11bhi/CD14hi liver macrophages in vivo. Subsequent analyses, including studies in mice with a myeloid cell–specific deletion of the TGF-β type II receptor, suggest that the availability of activated TGF-β and its downregulation by a hepatocyte-conditioned milieu are critical. Reduction of TGF-βRII-mediated signal transduction in myeloid cells leads to upregulation of IL-6, IL-10, and SIGLEC1 expression, a hallmark of the activation state of F4/80+/CD11bhi/CD14hi macrophages, and enhances liver regeneration. Conclusions: The availability of activated TGF-β determines the activation state of specific macrophage populations in the liver, and the observed rapid transient activation of TGF-β may represent an important regulatory mechanism in the early phase of liver regeneration in this context.

Authors: Stephanie D. Wolf, Christian Ehlting, Sophia Müller-Dott, Gereon Poschmann, Patrick Petzsch, Tobias Lautwein, Sai Wang, Barbara Helm, Marcel Schilling, Julio Saez-Rodriguez, Mihael Vucur, Kai Stühler, Karl Köhrer, Frank Tacke, Steven Dooley, Ursula Klingmüller, Tom Luedde, Johannes G. Bode

Date Published: 2023

Publication Type: Journal

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