Project description:Smith-Lemli-Opitz Syndrome (SLOS) is a developmental disorder caused by autosomal recessive mutations in the Dhcr7 gene. SLOS patients present clinically with multiple dysmorphologies, neurological, behavioral and cognitive defects, and demonstrate impaired cholesterol biosynthesis resulting in markedly elevated 7-DHC in all bodily tissues and fluids. Previous rodent models of SLOS suffered from neonatal mortality or variation in the biochemical phenotype over time. We generated a viable murine model bearing a conditional flosed allele of the Dhcr7 gene, and validated it by generating a mice with liver-specific deletion of Dhcr7 by breeding with a strain expressing Cre recombinase driven by an albumin promoter . These mice demonstrated elevated circulatory and liver 7-DHC levels, but phenotypic characterization of the knockout mice revealed no significant changes in viability, fertility, growth curves, liver architecture, hepatic triglyceride secretion, and parameters of systemic glucose homeostasis. Investigation in to changes in the liver transcriptome were investigated withe RNAseq, and identified enrichment in various pathways, including steroid hormone biosynthesis and various cell signaling and metabolism pathways. Most notably missing from the list are the genes related to cholesterol biosynthesis. Generation of this Dhcr7 conditional knockout model will allow for better studies into the post natal effects of blocking cholesterol biosynthesis, accumulation of 7-DHC, and the role of DHCR7 in specific tissues.
Project description:Growth hormone signaling in hepatocytes is fundamentally important. Disruptions in this pathway have led to fatty liver and other metabolic abnormalities. Growth hormone signals through the JAK2/STAT5 pathway. Mice with hepatocyte specific deletion of STAT5 were previously shown to develop fatty liver. Our aim in this study was to determine the effect of deleting JAK2 in hepatocytes on liver gene expression. To do so, we generated animals with hepatocyte specific deletion of JAK2.
Project description:Growth hormone signaling in hepatocytes is fundamentally important. Disruptions in this pathway have led to fatty liver and other metabolic abnormalities. Growth hormone signals through the JAK2/STAT5 pathway. Mice with hepatocyte specific deletion of STAT5 were previously shown to develop fatty liver. Our aim in this study was to determine the effect of deleting JAK2 in hepatocytes on liver gene expression. To do so, we generated animals with hepatocyte specific deletion of JAK2. Hepatocyte-specific JAK2-deficient mice (JAK2L) were generated by mating floxed JAK2 mice (in a mixed (C57Bl/6:129Sv) background) to mice carrying an Alb promoter-regulated Cre transgene on a 100% C57Bl/6 background purchased from the Jackson Labs. Livers were harvested from 8 week old animals for RNA extraction and hybridization.
Project description:Modification of RNAs with N6-methadenosine (m6A) has gained attention in recent years as a general mechanism of gene regulation. In the liver, m6A and its associated machinery has been studied as a potential biomarker of disease and cancer, with impacts on metabolism, cell cycle regulation, and pro-cancer state signaling. In vivo studies have begun to explore the effects of m6A in the liver, but differences in outcome of deletion of m6A writers Mettl3 and Mettl14 have not been thoroughly described or explained. Similarly, in vivo studies of the effects of m6A readers such as Ythdf1 and Ythdf2 have not been extended to characterize impacts of dysregulation of these reader proteins in the liver. To understand Mettl14 function, as well as Ythdf1 and Ythdf2, we developed mouse models and found a Mettl14 deletion specific phenotype of progressive liver injury characterized by nuclear heterotypia, with studies highlighting changes in mRNA splicing, processing and export leading to increases in mRNA surveillance and recycling.
Project description:The effect of liver specific deletion of the insulin receptor substrate-1 (Irs1) and/or Irs2 upon gene expression in the fasted and fed liver of mice; and the effect of liver specific Foxo1 deletion in the Irs1 and Irs2 knockout liver during fasting and feeding.
Project description:RNA-sequencing analysis of liver gene expression after combinatorial liver-specific deletion of tumor suppressor genes in a mouse fatty liver disease and liver cancer model. Gene expression was determined at 16 weeks of age, before onset of liver tumor formation. Aim was to study how loss of atypical E2F transcription repressors affected gene expression in Pten-mutant livers.
Project description:Purpose: Next-generation sequencing (NGS) has revolutionized systems-based analysis of cellular pathways. The goals of this study are to reveal dynamics of liver tumourigenesis in different mouse model and identify some key regulators that control HCC initiation or progression. We also try to define a index based on transcriptome of samples to quantify tumor development stage. Methods: mRNA profiles of wild-type (WT), hepatocyte-specific shp2 deletion (Shp2−/−) mice (SKO), hepatocyte-specific pten deletion (Pten−/−) mice (PKO), and hepatocyte-specific shp2 and pten deletion mice (DKO) were generated by deep sequencing. The sequence reads that passed quality filters were mapped to Mouse genome using STAR, and mRNA profiles were obtained using cuffdiff. Results: quanlity control of mRNA profiles showed that the data captured key features of phenotypes. Significantly changed genes, pathways, biolgocial processes, ligand and receptor, epigenetic regulators et al of SKO, PKO, DKO mice at differnet age were obtaiend. Temporal gene expression patterns during liver tumorigenesis in SKO, PKO and DKO mice were obtained. Conclusions: Our study represents the first detailed analysis of temporal transcriptomes during liver tumourigenesis, with biologic replicates, generated by RNA-seq technology. The optimized data analysis workflows reported here should provide a framework for comprehensive investigations of expression profiles.
Project description:Genetic loss of the enzyme 3ß-hydroxysterol-∆24 reductase (DHCR24) results in Desmosterolosis (MIM #602398), a rare disease that presents with multiple congenital anomalies. Earlier studies to create a Dhcr24 global knockout mouse have failed as the pups died within 24 h of birth from lethal dermopathy. We generated a conditional knockout mouse model (Dhcr24flx/flx) and validated it by creating a liver-specific knockout Dhcr24flx/flx, Alb-Cre mouse using a mouse expressing cre recombinase driven by the albumin promoter. Despite increased circulatory and liver desmosterol due to loss of cholesterol synthesis in the liver, these mice demonstrated no marked changes in growth, fertility, hepatic architecture, lipoprotein secretion, etc. RNA-Seq analysis of the female mouse liver revealed no notable perturbations in pathways participating in cholesterol biosynthesis.