Jag1K295*/+ as a mouse model for Alagille syndrome
ABSTRACT: A new mouse mutant was identified at the Munich ENU mutagenesis project due to hyperactivity, head tossing, and circling behaviour. Neurological and gross morphological phenotyping of these mutant mice revealed impairment of the vestibular system. Using whole genome exome sequencing and a custom-made variant calling pipeline, we identified the causative mutation as an A->T substitution on the chromosome 2 at the position 128 in the exon 6 of jagged 1 (Jag1) gene. This introduces a premature termination codon at the position 883 of the cDNA. In humans, mutations in the JAG1 gene are associated with Alagille syndrome (ALGS1 ), a multisystem developmental disorder mainly affecting small bile ducts in the liver, but also heart, skeleton, and eyes, and occasionally also kidney or inner ears. Further examination of the Jag1K295*/+ mutant mouse line disclosed multiorgan deficiencies, such as cardiac liver congestion, bile duct hypoplasia, mild nephropathy, subvalvular hypertrophy of the right ventricle, and mild growth retardation. No skeletal abnormalities could be detected. In summary, we report a novel mouse model for Alagille syndrome, Jag1K295*/+, which resembles most of the features of the mild form of Alagille syndrome observed in patients. Total RNA obtained from liver of 4 male heterozygous Jag1K295*/+ and 4 male wildtype mice
Project description:Members of the HMGN protein family bind to nucleosomes and affect chromatin structure and functions as transcription, replication and DNA repair as well as epigenetic modifications. Overexpression of Hmgn1 may be linked to the etiology of Down syndrome while underexpression may be linked to some leukemias. Hmgn3 is highly expressed in eye and in brain and might influence behavioral phenotype. For Hmgn5 effects on transcription levels e.g. in liver are suggested. Total RNA obtained from four homozygote mutant and wildtype male mice were compared.
Project description:The function of the SMC5-6 complex is less clear, but it has an important role in a variety of different DNA repair processes and in resolving recombination structures. Interestingly mutation at a highly conserved residue (Ser994) in the ATP hydrolysis motif in the SMC6 C-terminal domain, resulted in mice with a mild phenotype. Total RNA obtained from homozygote 4 male mutant mice was compared to 2-4 wild type or 2 heterozygote controls.
Project description:PRDM family members encode for progeins functionally associated with the control of cell proliferation, differentiation as well as apoptosis action in cell and tissue-specific menner. As important factors in maintenance and differentiation of human and mouse ES cells several PRDM family members were identified. Prdm11 has and outsider position within the PRDM family due to the lack of zinc-finger domains. However, a zic-finger binding motive i present and likely assue the function of protein-protein interactionl. Prdm11 was described as a candidate for tumor suppresser. However, the function of this gene is still unknown. Our study give evidence a new functional association of Prdm11 in allergic disease and asthma. Total RNA obtained from 1/2 lung of 4 female mice of each analysed group (widltype, wildtype challenged, mutant, mutant challenged)
Project description:PPARδ is emerging as a key metabolic regulator with pleiotropic actions on various tissues including fat, skeletal muscle and liver. The aim of our study was to assess the effect of either the well-validated PPARδ agonist GW501516, or a novel PPARδ agonist KD3010 in mouse models of liver fibrosis. KD3010, but not GW501516, treated mice had markedly less liver injury induced by carbon tetrachloride (CCl4) injections. Deposition of extracellular matrix proteins was lower in the KD3010 group as compared to the vehicle or GW501516 treated group. Interestingly, profibrogenic CTGF was significantly induced by GW501516, but not KD3010, following CCl4 treatment. The hepatoprotective and antifibrotic effect of KD3010 was confirmed in a model of cholestasis-induced liver injury and fibrosis using bile duct ligation for three weeks. Hepatocytes were identified as targets for PPARδ agonist, and primary hepatocytes treated with KD3010 showed decreased serum starvation or CCl4-induced cell death, while GW501516 treated hepatocytes were not protected. KD3010 treatment of hepatocytes decreased reactive oxygen species (ROS) production after CCl4 exposure. In conclusion, our data demonstrate that a novel PPARδ agonist has hepatoprotective and antifibrotic effects in animal models of liver fibrosis. Given the oral availability and the favorable pharmacologic profile of KD3010, ligand activation of PPARδ represents an attractive and promising target for patients with chronic liver diseases. Total RNA was extracted from primary mouse hepatocytes treated with DMSO or PPARd agonists (KD3010, GW1516)
Project description:Chronic hepatitis B, C and D virus (HBV, HCV, HDV) infections are leading causes of liver disease and cancer worldwide. Although these viruses differ markedly in their life cycle and genomic organization, they exclusively infect hepatocytes. Recently, the sodium taurocholate cotransporting polypeptide (NTCP) was identified as the first functional receptor for HBV and HDV. Here, we report that NTCP also facilitates HCV entry into human hepatocytes, by augmenting the bile acid-mediated repression of IFN-stimulated genes (ISGs), including IFITM2 and IFITM3, to increase the susceptibility of cells to HCV entry. Furthermore, an HBV-derived preS1 peptide, known to bind NTCP and to inhibit bile acid uptake and HBV infection, inhibits HCV entry by enhancing the expression of ISGs. Our study highlights NTCP as a novel player linking bile acid metabolism to the interferon response in hepatocytes and establishes a role for NTCP in the entry process of multiple hepatotropic viruses, via distinct mechanisms. Collectively, these findings enhance our understanding of hepatitis virus-host interactions and suggest NTCP as an attractive antiviral target for HBV/HCV co-infection. Transcriptome profiling by DNA microarray of Huh7.5.1 cells transduced to express NTCP.
Project description:Within a mutatgenesis screen, we identified the new recessive mouse mutant KTA48 with a kinky tail, white spots on coat and with small eyes. Aim of the actual study was the molecular characterization of the mutant and the functional consequences of the mutation. We mapped the mutation to mouse chromosome 12 within a critical interval of 2.4 Mb between the markers D12Mit171 and D12Mit270; sequence analysis of Pxdn revealed a T->A mutation at position 3816 (T3816A) resulting in a premature stop codon (Cys1272X) in teh perosidasin domain. Histological analysis revealed variable, but severe defects in teh eye including all major ocular tissues (cornea, lens and retina). These findings demonstrate severe clinical findings of a recessive mutation affecting peroxidasin. Total RNA obtained from homozygote embryos E12.5 and wildtype embryos E12.5, each sample include 4 eyes of two embryos
Project description:Background & Aims: Rapid induction of beta-PDGF receptor (beta-PDGFR) is a core feature of hepatic stellate cell activation, the hallmark of liver fibrogenesis. However, biological consequences of the induction are not well characterized. We aimed to determine the involvement of beta-PDGFR-mediated molecular pathway activation on hepatic stellate cells in liver injury, fibrogenesis, and carcinogenesis in vivo. Methods: Loss and constitutive activation of beta-PDGFR were assessed in mouse models with either a stellate cell-specific beta-PDGFR knockout or the expression of an autoactivating mutation respectively. Liver injury and fibrosis were induced in two mechanistically distinct models: carbontetrachloride (CCl4) treatment and ligation of the common bile duct. Hepatocarcinogenesis with underlying liver injury/fibrosis was assessed by a single dose of diethylnitrosamine (DEN) followed by repeated injections of CCl4. Genome-wide expression profiling was performed isolated stellate cells from these models to determine deregulated pathways. Results: Depletion of beta-PDGFR in hepatic stellate cells led to decreased histological liver injury, serum transaminases, collagen alpha 1(I) and alpha smooth muscle actin expression, and collagen deposition. Stellate cell proliferation was significantly reduced after acute hepatic injury in vivo. In contrast, autoactivation of beta-PDGFR in stellate cells accelerated liver fibrosis, most prominently after 6 weeks of CCl4 induced injury. There was no difference in development of DEN-induced pre-neoplastic loci according to the status of beta-PDGFR. Conclusions: Depletion of beta-PDGFR in hepatic stellate cells attenuated the development of liver injury, fibrosis, and stellate cell proliferation in multiple animal models, whereas the constitutive activation of beta-PDGFR enhanced fibrosis. However, manipulation of beta-PDGFR alone did not reduce development of dysplastic nodules. These findings indicate that titration of receptor beta-PDGFR expression on stellate cells parallels fibrosis and injury, but may not impact the development of hepatic neoplasia alone. Hepatic stellate cells were isolated from liver of beta-PDGFR-wild-type or knockout mice, and treated with beta-PDGF ligand or vehicle control.
Project description:Gene-expression profiles of rat liver cirrhosis induced by diethylnitrosamine and the effect of erlotinib on liver fibrogenesis and liver cancer development Hepatocellular carcinoma (HCC) is the sixth most common solid tumor worldwide and the third leading cause of cancer-related death. Given the lack of successful treatment options, chemoprevention in high-risk patients has been proposed as an alternative strategy. Mounting evidence supports a role for epidermal growth factor (EGF) during chronic liver disease and hepatocellular transformation. We address the hypothesis that blocking the EGF-EGF receptor (EGFR) pathway may be an effective strategy for inhibiting fibrogenesis and hepatocarcinogenesis. A rat model of diethylnitrosamine (DEN)-induced cirrhosis was used to examine the effects of erlotinib on underlying chronic liver disease and HCC formation. The DEN-induced rat model closely resembles disease progression in humans both pathologically and molecularly. Erlotinib significantly prevented the development of HCC tumor nodules in a dose-dependent fashion. Further, erlotinib inhibited the activation of hepatic stellate cells and prevented fibrogenesis. Erlotinib also reduced hepatotoxicity and improved liver function. Finally, a gene expression signature predictive of poor survival in human cirrhosis patients was reversed in response to erlotinib. Our data demonstrate for the first time that EGFR inhibition prevents liver fibrogenesis. Further, our results suggest that erlotinib is a potentially effective HCC chemoprevention strategy through inhibition of cirrhosis progression which can be monitored at the molecular level. Keywords: Cirrhotic liver, Expression array, Illumina, Signatures, Outcome prediction Animals received humane care according to the criteria outlined in the “Guide for the Care and Use of Laboratory Animals” of the National Academy of Sciences. All animals were maintained in accordance with the institutional guidelines of the Massachusetts General Hospital Subcommittee on Research Animal Care. Male Wistar rats received weekly IP injections of diethylnitrosamine (DEN) at 50 mg/kg, 100mg/kg, or vehicle control (PBS) for 18 weeks. A subset of rats received either daily (5X a week) IP injections of 2 mg/kg erlotinib or vehicle control during weeks 13 - 18. In a separate study, the erlotinib dose was lowered to 0.5 mg/kg. The vehicle groups from the two studies were not significantly different so they were combined together for analysis. Rats were weighed at the end of each week. Animals were sacrificed at 9, 13 and 19 weeks after a one-week washout period to eliminate acute effects of DEN. At the time of sacrifice, the non-tumor liver tissues were collected in RNase-free tubes and snap-frozen in liquid nitrogen. Frozen tissues were stored at -80°C until RNA extraction.
Project description:Cytochrome c oxidase (COX) is a 13-subunit enzyme that is a key complex of the oxidative phosphorylation system of the mitochondria, which generates the vast majority of the energy of the cell.COX subunit IV is the largest nuclear-encode subunit with important regulatory functions concerning energy metabolism. COX4-2 has been knocked out. Our study indicated strong expression of Cox4-2 in lung and therefore we test this mutant line under OVA-challenge conditions expecting a new asthma mouse model. Total RNA obtained from 1/2 lung of 4 female mice of each analysed group (widltype, wildtype challenged, mutant, mutant challenged)
Project description:Tmprss6 is the master inhibitor of hepcidin and its inactivation causes iron refractory iron deficiency anemia both in human and in mice. Mice with iron deficiency anemia (IDA)-low hepcidin show a pro-inflammatory response that is blunted in iron deficienct-high hepcidin Tmprss6 null mice. We investigated the transcriptional response associated with chronic hepcidin overexpression by comparing whole genome transcription profiling of the liver of Tmprss6 KO mice and IDA animals, irrespective of iron deficiency. Total liver RNA obtained from Tmprss6 KO mice were compared to wild type (iron deficient) animals, under basal conditions and after LPS challenge