Publications

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68 Publications visible to you, out of a total of 68

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Authors: Silvia Colucci, Sandro Altamura, Oriana Marques, Anne Dropmann, Natalie K. Horvat, Katja Müdder, Seddik Hammad, Steven Dooley, Martina U. Muckenthaler

Date Published: 13th May 2021

Publication Type: Journal

Abstract (Expand)

Fibroblast growth factor 23 (FGF23), a hormone generally derived from bone, is important in phosphate and vitamin D homeostasis. In acute kidney injury (AKI) patients, high-circulating FGF23 levels are associated with disease progression and mortality. However, the organ and cell type of FGF23 production in AKI and the molecular mechanism of its excessive production are still unidentified. For insight, we investigated folic acid (FA)-induced AKI in mice. Interestingly, simultaneous with FGF23, orphan nuclear receptor ERR-γ expression is increased in the liver of FA-treated mice, and ectopic overexpression of ERR-γ was sufficient to induce hepatic FGF23 production. In patients and in mice, AKI is accompanied by up-regulated systemic IL-6, which was previously identified as an upstream regulator of ERR-γ expression in the liver. Administration of IL-6 neutralizing antibody to FA-treated mice or of recombinant IL-6 to healthy mice confirms IL-6 as an upstream regulator of hepatic ERR-γ-mediated FGF23 production. A significant (<i>P</i> &lt; 0.001) interconnection between high IL-6 and FGF23 levels as a predictor of AKI in patients that underwent cardiac surgery was also found, suggesting the clinical relevance of the finding. Finally, liver-specific depletion of ERR-γ or treatment with an inverse ERR-γ agonist decreased hepatic FGF23 expression and plasma FGF23 levels in mice with FA-induced AKI. Thus, inverse agonist of ERR-γ may represent a therapeutic strategy to reduce adverse plasma FGF23 levels in AKI.

Authors: Kamalakannan Radhakrishnan, Yong-Hoon Kim, Yoon Seok Jung, Don-Kyu Kim, Soon-Young Na, Daejin Lim, Dong Hun Kim, Jina Kim, Hyung-Seok Kim, Hyon E Choy, Sung Jin Cho, In-Kyu Lee, Şamil Ayvaz, Stefanie Nittka, Danilo Fliser, Stefan J Schunk, Thimoteus Speer, Steven Dooley, Chul-Ho Lee, Hueng-Sik Choi

Date Published: 20th Apr 2021

Publication Type: Journal

Abstract

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Authors: P Erdoesi, E Karatayli, F Lammert, S Dooley, S Hammad

Date Published: 2021

Publication Type: Proceedings

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Authors: Fatma El-Zahraa Ammar Mohamed, Seddik Hammad, Tu Vinh Luong, Bedair Dewidar, Rajai Al-Jehani, Nathan Davies, Steven Dooley, Rajiv Jalan

Date Published: 1st Aug 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

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Authors: Anne Dropmann, Steven Dooley, Bedair Dewidar, Seddik Hammad, Tatjana Dediulia, Julia Werle, Vanessa Hartwig, Shahrouz Ghafoory, Stefan Woelfl, Hanna Korhonen, Michel Janicot, Katja Wosikowski, Timo Itzel, Andreas Teufel, Detlef Schuppan, Ana Stojanovic, Adelheid Cerwenka, Stefanie Nittka, Albrecht Piiper, Timo Gaiser, Naiara Beraza, Malgorzata Milkiewicz, Piotr Milkiewicz, John G Brain, David E J Jones, Thomas S Weiss, Ulrich M Zanger, Matthias Ebert, Nadja M Meindl-Beinker

Date Published: 28th Jan 2020

Publication Type: Not specified

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Authors: Peter L. M. Jansen, Kai Breuhahn, Andreas Teufel, Steven Dooley

Date Published: 22nd Nov 2019

Publication Type: Not specified

Abstract (Expand)

Liver fibrosis is an advanced liver disease condition, which could progress to cirrhosis and hepatocellular carcinoma. To date, there is no direct approved antifibrotic therapy, and current treatment is mainly the removal of the causative factor. Transforming growth factor (TGF)-beta is a master profibrogenic cytokine and a promising target to treat fibrosis. However, TGF-beta has broad biological functions and its inhibition induces non-desirable side effects, which override therapeutic benefits. Therefore, understanding the pleiotropic effects of TGF-beta and its upstream and downstream regulatory mechanisms will help to design better TGF-beta based therapeutics. Here, we summarize recent discoveries and milestones on the TGF-beta signaling pathway related to liver fibrosis and hepatic stellate cell (HSC) activation, emphasizing research of the last five years. This comprises impact of TGF-beta on liver fibrogenesis related biological processes, such as senescence, metabolism, reactive oxygen species generation, epigenetics, circadian rhythm, epithelial mesenchymal transition, and endothelial-mesenchymal transition. We also describe the influence of the microenvironment on the response of HSC to TGF-beta. Finally, we discuss new approaches to target the TGF-beta pathway, name current clinical trials, and explain promises and drawbacks that deserve to be adequately addressed.

Authors: B. Dewidar, C. Meyer, S. Dooley, A. N. Meindl-Beinker

Date Published: 11th Nov 2019

Publication Type: Not specified

Abstract (Expand)

BACKGROUND & AIMS: Activation of transforming growth factor beta (TGFB) promotes liver fibrosis by activating hepatic stellate cells (HSCs), but the mechanism of TGFB activation are not clear. We investigated the role of extracellular matrix protein 1 (ECM1), which interacts with extracellular and structural proteins, in TGFB activation in livers of mice. METHODS: We performed studies with e C57BL/6J mice (controls), ECM1-knockout (ECM1-KO) mice, and mice with hepatocyte-specific knockout of EMC1 (ECM1Deltahep). ECM1 or soluble TGFB receptor 2 (TGFBR2) were expressed in livers of mice following injection of an adeno-associated virus vector. Liver fibrosis was induced by carbon tetrachloride (CCl4) administration. Livers were collected from mice and analyzed by histology, immunohistochemistry, in situ hybridization, and immunofluorescence analyses. Hepatocytes and HSCs were isolated from livers of mice and incubated with ECM1; production of cytokines and activation of reporter genes were quantified. Liver tissues from patients with viral or alcohol-induced hepatitis (with different stages of fibrosis) and individuals with healthy liver were analyzed by immunohistochemistry and in situ hybridization. RESULTS: ECM1-KO mice spontaneously developed liver fibrosis and died by 2 months of age without significant hepatocyte damage or inflammation. In liver tissues of mice, we found that ECM1 stabilized extracellular matrix-deposited TGFB in its inactive form by interacting with alphav integrins to prevent activation of HSCs. In liver tissues from patients and in mice with CCl4-induced liver fibrosis, we found an inverse correlation between level of ECM1 and severity of fibrosis. CCl4-induced liver fibrosis was accelerated in ECM1Deltahep mice compared with control mice. Hepatocytes produced the highest levels of ECM1 in livers of mice. Ectopic expression of ECM1 or soluble TGFBR2 in liver prevented fibrogenesis in ECM1-KO mice and prolonged their survival. Ectopic expression of ECM1 in liver also reduced the severity of CCl4-induced fibrosis in mice. CONCLUSIONS: ECM1, produced by hepatocytes, inhibits activation of TGFB and its activation of HSCs to prevent fibrogenesis in mouse liver. Strategies to increase levels of ECM1 in liver might be developed for treatment of fibrosis.

Authors: W. Fan, T. Liu, W. Chen, S. Hammad, T. Longerich, Y. Fu, N. Li, Y. He, C. Liu, Y. Zhang, Q. Lian, X. Zhao, C. Yan, L. Li, C. Yi, Z. Ling, L. Ma, X. Zhao, H. Xu, P. Wang, M. Cong, H. You, Z. Liu, Y. Wang, J. Chen, D. Li, L. Hui, S. Dooley, J. Hou, J. Jia, B. Sun

Date Published: 27th Jul 2019

Publication Type: Not specified

Abstract (Expand)

Liver inflammation and macrophage infiltration are critical steps in the progression of nonalcoholic fatty liver to the development of nonalcoholic steatohepatitis. Bone morphogenetic protein9 is a cytokine involved in the regulation of chemokines and lipogenesis. However, the function of bone morphogenetic protein9 in nonalcoholic steatohepatitis is still unknown. The present study hypothesized that bone morphogenetic protein9 may contribute to steatohepatitis in mice fed a methionine choline deficiency diet (MCD). C57BL/6 mice overexpressing bone morphogenetic protein9 and control mice were fed the MCD diet for 4 weeks. Liver tissue and serum samples were obtained for subsequent measurements. Bone morphogenetic protein9 overexpression exacerbated steatohepatitis in mice on the MCD diet, as indicated by liver histopathology, increased serum alanine aminotransferase activity, aspartate transaminase activity, hepatic inflammatory gene expression and M1 macrophage recruitment. Although bone morphogenetic protein9 overexpression did not affect the expression of profibrogenic genes, including Collagen I (alpha)1 or matrix metalloproteinase (MMP) 9, it did upregulate the expression of transforming growth factorbeta and plasminogen activator inhibitor 1, and downregulated the expression of MMP2. The above results indicate that bone morphogenetic protein9 exerts a proinflammatory role in MCD dietinduced nonalcoholic steatohepatitis.

Authors: Q. Li, B. Liu, K. Breitkopf-Heinlein, H. Weng, Q. Jiang, P. Dong, S. Dooley, K. Xu, H. Ding

Date Published: 20th Jul 2019

Publication Type: Not specified

Abstract (Expand)

OBJECTIVE: Although glial cell line-derived neurotrophic factor (GDNF) is a member of the transforming growth factor-beta superfamily, its function in liver fibrosis has rarely been studied. Here, we investigated the role of GDNF in hepatic stellate cell (HSC) activation and liver fibrosis in humans and mice. DESIGN: GDNF expression was examined in liver biopsies and sera from patients with liver fibrosis. The functional role of GDNF in liver fibrosis was examined in mice with adenoviral delivery of the GDNF gene, GDNF sgRNA CRISPR/Cas9 and the administration of GDNF-blocking antibodies. GDNF was examined on HSC activation using human and mouse primary HSCs. The binding of activin receptor-like kinase 5 (ALK5) to GDNF was determined using surface plasmon resonance (SPR), molecular docking, mutagenesis and co-immunoprecipitation. RESULTS: GDNF mRNA and protein levels are significantly upregulated in patients with stage F4 fibrosis. Serum GDNF content correlates positively with alpha-smooth muscle actin (alpha-SMA) and Col1A1 mRNA in human fibrotic livers. Mice with overexpressed GDNF display aggravated liver fibrosis, while mice with silenced GDNF expression or signalling inhibition by GDNF-blocking antibodies have reduced fibrosis and HSC activation. GDNF is confined mainly to HSCs and contributes to HSC activation through ALK5 at His(39) and Asp(76) and through downstream signalling via Smad2/3, but not through GDNF family receptor alpha-1 (GFRalpha1). GDNF, ALK5 and alpha-SMA colocalise in human and mouse HSCs, as demonstrated by confocal microscopy. CONCLUSIONS: GDNF promotes HSC activation and liver fibrosis through ALK5/Smad signalling. Inhibition of GDNF could be a novel therapeutic strategy to combat liver fibrosis.

Authors: L. Tao, W. Ma, L. Wu, M. Xu, Y. Yang, W. Zhang, W. Sha, H. Li, J. Xu, R. Feng, D. Xue, J. Zhang, S. Dooley, E. Seki, P. Liu, C. Liu

Date Published: 6th Jun 2019

Publication Type: Not specified

Abstract

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Authors: Ersin Karatayli, Rabea A. Hall, Susanne N. Weber, Steven Dooley, Frank Lammert

Date Published: 1st Feb 2019

Publication Type: Not specified

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Authors: S Hammad, JG Hengstler, S Dooley

Date Published: 2019

Publication Type: Not specified

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Authors: S Dooley, W Fan, S Hammad, K Gould, T Longerich, T Liu, W Chen, C Liu, J Hou, J Jia, B Sun

Date Published: 2019

Publication Type: Not specified

Abstract

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Authors: B Dewidar, A Dropmann, K Gould, V Hartwig, C Dormann, S Dooley, S Hammad

Date Published: 2019

Publication Type: Not specified

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