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9 result(s) for "Marhenke, Silke"
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TNF-Receptor-1 inhibition reduces liver steatosis, hepatocellular injury and fibrosis in NAFLD mice
Non-alcoholic fatty liver disease (NAFLD) shows an increasing prevalence and is associated with the development of liver fibrosis and cirrhosis as the major risk factors of liver-related mortality in this disease. The therapeutic possibilities are limited and restricted to life style intervention, since specific drugs for NAFLD are unavailable so far. TNFα has been implicated as a major pathogenic driver of NAFLD. TNFα-mediated liver injury occurs mainly via TNF-receptor-1 (TNFR1) signaling, whereas TNFR2 mediates protective pathways. In this study, we analyzed the therapeutic effects of a novel antibody, which selectively inhibits TNFR1 while retaining protective TNFR2 signaling in a high-fat diet (HFD) mouse model of NAFLD. Mice were fed with HFD for 32 weeks and treated with anti-TNFR1-antibody or control-antibody for the last 8 weeks. We then investigated the mechanisms of TNFR1 inhibition on liver steatosis, inflammatory liver injury, insulin resistance and fibrosis. Compared to control-antibody treatment, TNFR1 inhibition significantly reduced liver steatosis and triglyceride content, which was accompanied by reduced expression and activation of the transcription factor SREBP1 and downstream target genes of lipogenesis. Furthermore, inhibition of TNFR1 resulted in reduced activation of the MAP kinase MKK7 and its downstream target JNK, which was associated with significant improvement of insulin resistance. Apoptotic liver injury, NAFLD activity and alanine aminotransferase (ALT) levels, as well as liver fibrosis significantly decreased by anti-TNFR1 compared to control-antibody treatment. Thus, our results suggest selective TNFR1 inhibition as a promising approach for NAFLD treatment.
The TNFR1 Antagonist Atrosimab Is Therapeutic in Mouse Models of Acute and Chronic Inflammation
Therapeutics that block tumor necrosis factor (TNF), and thus activation of TNF receptor 1 (TNFR1) and TNFR2, are clinically used to treat inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease and psoriasis. However, TNFR1 and TNFR2 work antithetically to balance immune responses involved in inflammatory diseases. In particular, TNFR1 promotes inflammation and tissue degeneration, whereas TNFR2 contributes to immune modulation and tissue regeneration. We, therefore, have developed the monovalent antagonistic anti-TNFR1 antibody derivative Atrosimab to selectively block TNFR1 signaling, while leaving TNFR2 signaling unaffected. Here, we describe that Atrosimab is highly stable at different storage temperatures and demonstrate its therapeutic efficacy in mouse models of acute and chronic inflammation, including experimental arthritis, non-alcoholic steatohepatitis (NASH) and experimental autoimmune encephalomyelitis (EAE). Our data support the hypothesis that it is sufficient to block TNFR1 signaling, while leaving immune modulatory and regenerative responses via TNFR2 intact, to induce therapeutic effects. Collectively, we demonstrate the therapeutic potential of the human TNFR1 antagonist Atrosimab for treatment of chronic inflammatory diseases.
Murine Liver Organoids as a Genetically Flexible System to Study Liver Cancer In Vivo and In Vitro
The rising incidence of cholangiocarcinoma (CCA) coupled with a low 5‐year survival rate that remains below 10% delineates the urgent need for more effective treatment strategies. Although several recent studies provided detailed information on the genetic landscape of this fatal malignancy, versatile model systems to functionally dissect the immediate clinical relevance of the identified genetic alterations are still missing. To enhance our understanding of CCA pathophysiology and facilitate rapid functional annotation of putative CCA driver and tumor maintenance genes, we developed a tractable murine CCA model by combining the cyclization recombination (Cre)‐lox system, RNA interference, and clustered regularly interspaced short palindromic repeats/CRISPR associated protein 9 (CRISPR/Cas9) technology with liver organoids, followed by subsequent transplantation into immunocompetent, syngeneic mice. Histologically, resulting tumors displayed cytokeratin 19–positive ductal structures surrounded by a desmoplastic stroma—hallmark features of human CCAs. Despite their initial biliary phenotype in vitro, organoids retained the plasticity to induce a broader differentiation spectrum of primary liver cancers following transplantation into recipient mice, depending on their genetic context. Thus, the organoid system combines the advantage of using nontransformed, premalignant cells to recapitulate liver tumorigenesis as a multistep process, with the advantage of a reproducible and expandable cell culture system that abrogates the need for recurrent isolations of primary cells. Conclusion: Genetically modified liver organoids are able to transform into histologically accurate CCAs. Depending on the oncogenic context, they are also able to give rise to liver cancers that show features of hepatocellular carcinomas. The model can be used to functionally explore candidate cancer genes of primary liver cancers in immunocompetent animals and evaluate novel treatment regimens. Genetically modified liver organoids are able to transform into histologically accurate cholangiocarcinomas. Depending on the oncogenic context, they are also able to give rise to liver cancers that show features of hepatocellular carcinomas. This organoid‐based model can be used to functionally explore candidate cancer genes of primary liver cancers in immunocompetent animals and evaluate novel treatment regimens.
Hepatocyte-specific S100a8 and S100a9 transgene expression in mice causes Cxcl1 induction and systemic neutrophil enrichment
Background Calprotectin consists of the Ca 2+ -binding proteins S100a8 and S100a9 that are induced in epithelial cells in response to tissue damage and infection. Both proteins are also secreted by activated innate immune cells and numerous studies demonstrate their crucial role in pathological conditions of acute and chronic inflammation. Results Here, we established a conditional mouse model with simultaneous S100a8 and S100a9 transgene expression in hepatocytes ( TgS100a8a9 hep ) under the control of doxycycline to unravel the role of epithelial-derived Calprotectin on tissue homeostasis and inflammation. TgS100a8a9 hep mice displayed a significant enrichment of neutrophils in peripheral blood and tissues with high blood content. Interestingly, Cxcl1 transcription was significantly induced in the liver of TgS100a8a9 hep mice and primary hepatocytes derived thereof as compared to Control mice, accompanied by an increase of Cxcl1 serum levels. However, expression of other chemokines with a known function in neutrophil mobilization from the bone marrow, e.g. Csf3 and Cxcl2, was not altered. Doxycycline treatment of TgS100a8a9 hep mice reduced Cxcl1 expression in the liver and resulted in normal numbers of neutrophils. Conclusion In summary, our data demonstrate for the first time that hepatocyte-specific S100a8 and S100a9 expression induces a systemic mobilization of neutrophils by a specific activation of Cxcl1 transcription in the liver.
Genetic variants in PNPLA3 and TM6SF2 predispose to the development of hepatocellular carcinoma in individuals with alcohol-related cirrhosis
ObjectivesVariants in patatin-like phospholipase domain-containing 3 (PNPLA3; rs738409), transmembrane 6 superfamily member 2 (TM6SF2; rs58542926), and membrane bound O-acyltransferase domain containing 7 (MBOAT7; rs641738) are risk factors for the development of alcohol-related cirrhosis. Within this population, PNPLA3 rs738409 is also an established risk factor for the development of hepatocellular carcinoma (HCC). The aim of this study was to explore possible risk associations of TM6SF2 rs58542926 and MBOAT7 rs641738 with HCC.MethodsRisk variants in PNPLA3, TM6SF2, and MBOAT7 were genotyped in 751 cases with alcohol-related cirrhosis and HCC and in 1165 controls with alcohol-related cirrhosis without HCC. Association with the risk of developing HCC was analyzed using multivariate logistic regression.ResultsThe development of HCC was independently associated with PNPLA3 rs738409 (ORadjusted 1.84 [95% CI 1.55-2.18], p = 1.85 × 10-12) and TM6SF2 rs58542926 (ORadjusted 1.66 [1.30-2.13], p = 5.13 × 10-05), using an additive model, and controlling the sex, age, body mass index, and type 2 diabetes mellitus; the risk associated with carriage of MBOAT7 rs641738 (ORadjusted 1.04 [0.88-1.24], p = 0.61) was not significant. The population-attributable fractions were 43.5% for PNPLA3 rs738409, 11.5% for TM6SF2 rs58542926, and 49.9% for the carriage of both the variants combined.ConclusionsCarriage of TM6SF2 rs58542926 is an additional risk factor for the development of HCC in people with alcohol-related cirrhosis. Carriage of both PNPLA3 rs738409 and TM6SF2 rs58542926 accounts for half of the attributable risk for HCC in this population. Genotyping will allow for more precise HCC risk-stratification of patients with alcohol-related cirrhosis, and genotype-guided screening algorithms would optimize patient care.
Dynamic YAP expression in the non-parenchymal liver cell compartment controls heterologous cell communication
Introduction The Hippo pathway and its transcriptional effectors yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are targets for cancer therapy. It is important to determine if the activation of one factor compensates for the inhibition of the other. Moreover, it is unknown if YAP/TAZ-directed perturbation affects cell–cell communication of non-malignant liver cells. Materials and Methods To investigate liver-specific phenotypes caused by YAP and TAZ inactivation, we generated mice with hepatocyte (HC) and biliary epithelial cell (BEC)-specific deletions for both factors (YAPKO, TAZKO and double knock-out (DKO)). Immunohistochemistry, single-cell sequencing, and proteomics were used to analyze liver tissues and serum. Results The loss of BECs, liver fibrosis, and necrosis characterized livers from YAPKO and DKO mice. This phenotype was weakened in DKO tissues compared to specimens from YAPKO animals. After depletion of YAP in HCs and BECs, YAP expression was induced in non-parenchymal cells (NPCs) in a cholestasis-independent manner. YAP positivity was detected in subgroups of Kupffer cells (KCs) and endothelial cells (ECs). The secretion of pro-inflammatory chemokines and cytokines such as C-X-C motif chemokine ligand 11 (CXCL11), fms-related receptor tyrosine kinase 3 ligand (FLT3L), and soluble intercellular adhesion molecule-1 (ICAM1) was increased in the serum of YAPKO animals. YAP activation in NPCs could contribute to inflammation via TEA domain transcription factor (TEAD)-dependent transcriptional regulation of secreted factors. Conclusion YAP inactivation in HCs and BECs causes liver damage, and concomitant TAZ deletion does not enhance but reduces this phenotype. Additionally, we present a new mechanism by which YAP contributes to cell–cell communication originating from NPCs.
Safety and efficacy of chemosaturation in patients with primary and secondary liver tumors
Background Chemosaturation with percutaneous hepatic perfusion (CS-PHP; hepatic CHEMOSAT ® delivery system; Delcath Systems Inc, USA) is a novel medical device, which delivers high doses of melphalan directly to the liver in patients with primary and secondary liver tumors while limiting systemic toxicity through hemofiltration of the hepatic venous blood. The aim of this study was to analyze the safety and efficacy of the second-generation CS-PHP after 54 treatments at Hannover Medical School, Germany. Methods Overall response rates (ORR) were assessed according to response evaluation criteria in solid tumors (RECIST1.1). Overall survival (OS), progression-free survival (PFS), and hepatic PFS (hPFS) were analyzed using the Kaplan–Meier estimation. Results 29 patients were treated with CS-PHP as last-line therapy up to five sessions. 19 patients had unresectable hepatic metastases from solid tumors [ocular melanoma (OM) n  = 11; colorectal carcinoma n  = 2; pancreatic adenocarcinoma n  = 2; periampular carcinoma n  = 2; breast and endometrial cancer each n  = 1] and 10 patients were diagnosed with hepatocellular or cholangiocarcinoma (HCC/CCA). ORR was 19.2%. Patients with OM had the highest ORR (33.3%). Similar to patients with OM, patients with hepatobiliary tumors had durable disease stabilization (40%). Median OS, PFS, and hPFS were 261, 117, and 135 days, respectively. Tumor volume negatively correlated with OS. Complications and toxicities included thrombocytopenia, cardiovascular events, ulcerous bleeding, and edema. Conclusion Second-generation CS-PHP seems to be effective and tolerable. Patient selection based on tumor volume and entity is of importance. Particularly, patients with OM and hepatobiliary tumors represent promising candidates for CS-PHP.
p21 promotes sustained liver regeneration and hepatocarcinogenesis in chronic cholestatic liver injury
Background and aims The cyclin-dependent kinase inhibitor p21 has been implicated as a tumour suppressor. Moreover, recent genetic studies suggest that p21 might be a potential therapeutic target to improve regeneration in chronic diseases. The aim of this study was to delineate the role of p21 in chronic liver injury and to specify its role in hepatocarcinogenesis in a mouse model of chronic cholestatic liver injury. Methods The degree of liver injury, regeneration and tumour formation was assessed in Mdr2−/− mice and compared with Mdr2/ p21−/− mice. Moreover, the role of p21 was evaluated in hepatoma cells in vitro and in human hepatocellular carcinoma (HCC). Results Mdr2−/− mice developed HCCs as a consequence of chronic inflammatory liver injury. In contrast, tumour development was profoundly delayed in Mdr2/ p21−/− mice. Delayed tumour development was accompanied by markedly impaired liver regeneration in Mdr2/ p21−/− mice. Moreover, the regenerative capacity of the Mdr2/ p21−/− livers in response to partial hepatectomy declined with age in these mice. Hepatocyte transplantation experiments revealed that impaired liver regeneration was due to intrinsic factors within the cells and changes in the Mdr2/ p21−/− microenvironment. In human HCCs, a subset of tumours expressed p21, which was associated with a significant shorter patient survival. Conclusions We provide experimental evidence that p21 is required for sustained liver regeneration and tumour development in chronic liver injury indicating that p21 needs to be tightly regulated in order to balance liver regeneration and cancer risk. Moreover, we identify p21 as a negative prognostic marker in human HCC.
Correction: Genetic Variants in PNPLA3 and TM6SF2 Predispose to the Development of Hepatocellular Carcinoma in Individuals With Alcohol-Related Cirrhosis
Author Pierre Deltenre, MD should appear in the author list in position 25, between Felix Braun and Thomas Berg. He should also have a PhD degree added to his name.