Project description:This work is part of the paper: Generation of a murine hepatic angiosarcoma cell line and reproducible mouse tumor model, Rothweiler S et al, Laboratory Investigation, 2014 (accepted) Hepatic Angiosarcoma (AS) is a rare and highly aggressive tumor of endothelial origin with dismal prognosis. Studies of the molecular biology of AS and treatment options are limited since animal models are rare. We have previously shown that inducible knockout of Notch1 in mice leads to spontaneous formation of hepatic AS. The aim of this study was to 1) establish and characterize a cell line derived from this murine AS, 2) to identify molecular pathways involved in the pathogenesis and potential therapeutic targets, and 3) to generate a tumor transplantation model. AS cells retained specific endothelial properties such as tube formation activity, as well as expression of CD31 and von Willebrand Factor. However, electron microscopy analysis revealed signs of dedifferentiation with loss of fenestrae and loss of contact inhibition. Microarray and pathway analysis showed substantial changes in gene expression and revealed activation of the Myc pathway. Exposing the AS cells to sorafenib reduced migration, filopodia dynamics, and cell proliferation but did not induce apoptosis. In addition, sorafenib suppressed ERK phosphorylation and expression of cyclin D2. Injection of AS cells into NOD/SCID mice resulted in formation of undifferentiated tumors confirming the tumorigenic potential of these cells. Conclusion: We established and characterized a murine model of spontaneous AS formation and hepatic AS cell lines as a useful in vitro tool. Our data demonstrate antitumor activity of sorafenib in AS cells with potent inhibition of migration, filopodia formation, and cell proliferation, which support further evaluation of sorafenib as a novel treatment strategy. In addition, AS cell transplantation provides a subcutaneous tumor model useful for in vivo preclinical drug testing. Mouse liver samples (Notch1 knockout and wild type control, 3 animals per group) and angiosarcoma cell lines (3 independently derived lines) were analyzed.
Project description:This work is part of the paper: Generation of a murine hepatic angiosarcoma cell line and reproducible mouse tumor model, Rothweiler S et al, Laboratory Investigation, 2014 Hepatic Angiosarcoma (AS) is a rare and highly aggressive tumor of endothelial origin with dismal prognosis. Studies of the molecular biology of AS and treatment options are limited since animal models are rare. We have previously shown that inducible knockout of Notch1 in mice leads to spontaneous formation of hepatic AS. The aim of this study was to 1) establish and characterize a cell line derived from this murine AS, 2) to identify molecular pathways involved in the pathogenesis and potential therapeutic targets, and 3) to generate a tumor transplantation model. AS cells retained specific endothelial properties such as tube formation activity, as well as expression of CD31 and von Willebrand Factor. However, electron microscopy analysis revealed signs of dedifferentiation with loss of fenestrae and loss of contact inhibition. Microarray and pathway analysis showed substantial changes in gene expression and revealed activation of the Myc pathway. Exposing the AS cells to sorafenib reduced migration, filopodia dynamics, and cell proliferation but did not induce apoptosis. In addition, sorafenib suppressed ERK phosphorylation and expression of cyclin D2. Injection of AS cells into NOD/SCID mice resulted in formation of undifferentiated tumors confirming the tumorigenic potential of these cells. Conclusion: We established and characterized a murine model of spontaneous AS formation and hepatic AS cell lines as a useful in vitro tool. Our data demonstrate antitumor activity of sorafenib in AS cells with potent inhibition of migration, filopodia formation, and cell proliferation, which support further evaluation of sorafenib as a novel treatment strategy. In addition, AS cell transplantation provides a subcutaneous tumor model useful for in vivo preclinical drug testing.
Project description:Liver transcriptome profiling of liver specific miR-122 knockout (miR-122loxP/loxP Alb-Cre) and control (miR-122loxP/loxP) male mice. Expression profile of several hundred mRNAs that include miR-122 targets were altered in miR-122 KO livers. Loss of miR-122 in the germ line resulted in significant changes in hepatic gene expression profile. Among the upregulated genes many are direct targets of miR-122 GSM517838-GSM517847: Liver transcriptome profiling of liver specific miR-122 knockout and control male mice. Total liver RNA from 8 week old five control and five liver-specific miR-122 knock out male mice (C57/BL6J background) GSM791601-GSM791604: Liver transcriptome profiling of germ-line miR-122 knockout and control male mice. Liver RNA from 5 week old control (floxed) and miR-122KO mice were analyzed by mouse whole transcriptome profiling.
Project description:We studied the molecular mechanisms of hepatocellular carcinoma (HCC) initiation and promotion using the Mdr2-knockout (Mdr2-KO) mice at pre-cancerous stages of liver disease. These mice lack the liver-specific P-glycoprotein responsible for phosphatidylcholine transport across the canalicular membrane. Portal inflammation ensues at an early age followed by the development of HCC between the ages of 12 and 15 months. Liver tissue samples of Mdr2-KO and control Mdr2-heterozygotes mice aged 3 and 12 months, were subjected to histological, biochemical and gene expression profiling analysis using Affymetrix Mouse Genome Array. Keywords: HCC, murine model, precancerous stages, chronic liver desease
Project description:Notch signaling regulates cell-fate decisions in several developmental processes and cell functions. However, a role for Notch in hepatic thrombopoietin (TPO) production remains unclear. We noted thrombocytopenia in mice with hepatic Notch1 deficiency, and so investigated TPO production and other features of platelets in these mice. We found that the liver ultrastructure and hepatocyte function were comparable between control mice and Notch1-deficient mice. However, the Notch1-deficient mice had significantly lower plasma TPO and hepatic TPO mRNA levels, concomitant with lower numbers of platelets and impaired megakaryocyte differentiation and maturation, which were rescued by addition of exogenous TPO. Additionally, JAK2/STAT3 phosphorylation was significantly inhibited in Notch1-deficient hepatocytes, consistent with the RNA-seq analysis. JAK2/STAT3 phosphorylation and TPO production was also impaired in cultured Notch1-deficient hepatocytes after treatment with desialylated platelets. Consistently, hepatocyte-specific Notch1 deletion inhibited JAK2/STAT3 phosphorylation and hepatic TPO production induced by administration of desialylated platelets in vivo. Interestingly, Notch1 deficiency downregulated the expression of HES5 but not HES1. Moreover, desialylated platelets promoted the binding of HES5 to JAK2/STAT3, leading to JAK2/STAT3 phosphorylation and pathway activation in hepatocytes. Hepatocyte Ashwell-Morell receptor (AMR) (asialoglycoprotein receptor 1, ASGR1) physically associates with Notch1 and inhibition of AMR impaired Notch1 signaling activation and hepatic TPO production. Furthermore, blockage of Dll4 on desialylated platelets inhibited hepatocyte Notch1 activation and HES5 expression, JAK2/STAT3 phosphorylation and subsequent TPO production. In conclusion, our study identifies a novel regulatory role of Notch1 in hepatic TPO production, indicating that it might be a target for modulating TPO level.
Project description:We have previously shown that total estrogen receptor alpha (ERalpha knockout (KO) mice exhibit hepatic insulin resistance. To investigate the contribution of hepatic ERalpha action for the observed phenotype, we established a liver-selective ERalphaKO mouse model, LERKO. We demonstrate that LERKO mice have efficient reduction of ERalpha selectively within the liver. However, LERKO and wild type control mice do not differ in body weight, and have a comparable hormone profile as well as insulin and glucose response, even when challenged with a high fat diet. Furthermore, LERKO mice display very minor changes in their hepatic transcript profile. Collectively, our findings indicate that hepatic ERalpha action may not be the initiating factor for the previously identified hepatic insulin resistance in ERalphaKO mice. We have previously shown that total estrogen receptor alpha (ERalpha knockout (KO) mice exhibit hepatic insulin resistance. To investigate the contribution of hepatic ERalpha action for the observed phenotype, we established a liver-selective ERalphaKO mouse model, LERKO. Using microarray analysis, we compared the hepatic transcriptional profile of LERKO vs control mice.
Project description:Hepatic organoids are a recent innovation in in vitro modelling. Initial studies suggest organoids better recapitulate the liver phenotype in vitro compared to pre-existing proliferative cell models. However, their propensity for drug metabolism and detoxification remains poorly characterised. A global proteomic profiling of undifferentiated and differentiated hepatic murine organoids and donor-matched livers was therefore performed to assess both their similarity to liver tissue and DMET expression. iTRAQ analysis revealed 4,405 proteins commonly detected across all sample types. Differentiation of organoids significantly increased the expression of multiple CYP450s, phase II enzymes, liver biomarkers and hepatic transporters. While the final phenotype of differentiated organoids is distinct from liver tissue, they contain multiple DMET proteins necessary for liver function and drug metabolism, such as CYP450 3A, GSTA and MDR1A. Hepatic organoids may therefore represent an attractive novel model for hepatotoxicity testing, although further experimentation, optimisation and characterisation is needed relative to pre-existing models to fully contextualise their use as a putative in vitro model of DILI.
Project description:Background and Aims: The activation of stimulator of interferon genes (STING) and NOD-like receptors protein 3 (NLRP3) inflammasomes-mediated pyroptosis signaling pathways represent two distinct central mechanisms in liver disease. However, the interconnection between these two pathways and the epigenetic regulation of the STING-NLRP3 axis in hepatocyte pyroptosis during liver fibrosis remain unknown and is the focus of this study. Approach and Results: Liver fibrosis was induced in Sting knockout, Gasdermin D (Gsdmd) knockout mice, and in mice with hepatocyte-specific Nlrp3 deletion. RNA-sequencing, metabolomics, epigenetic compound screening system, and chromatin immunoprecipitation were utilized. STING and NLRP3 inflammasome signaling pathways were activated in cirrhotic livers but were suppressed by Sting knockout. Sting knockout also ameliorated hepatic pyroptosis, inflammation, and fibrosis in the murine cirrhotic model. In vitro, STING induced pyroptosis in primary murine hepatocytes via activating the NLRP3 inflammasome. H3K4-specific histone methyltransferase WD repeat-containing protein 5 (WDR5) and DOT1-like histone H3K79 methyltransferase (DOT1L) were identified to regulate NLRP3 expression in STING-overexpressed AML12 hepatocytes. WDR5/DOT1L-mediated histone methylation enhanced interferon regulatory transcription factor 3 (IRF3) binding to the Nlrp3 promoter and promoted STING-induced Nlrp3 transcription in hepatocytes. The RNA-sequencing and metabolomics analysis in murine livers and primary hepatocytes showed that metabolic reprogramming might participate in NLRP3-mediated hepatocyte pyroptosis and liver fibrosis. Moreover, hepatocyte-specific Nlrp3 deletion and downstream Gsdmd knockout attenuated hepatic pyroptosis, inflammation, and fibrosis in murine cirrhotic models. Conclusions: This study describes a novel epigenetic mechanism by which the STING-WDR5/DOT1L/IRF3-NLRP3 signaling pathway enhances hepatocyte pyroptosis and hepatic inflammation in liver fibrosis.