Project description:Inactivating mutations in the copper transporter Atp7b result in Wilson’s disease. The Atp7b-/- mouse develops hallmarks of Wilson’s disease. The activity of several nuclear receptors is decreased in Atp7b-/- mice, and nuclear receptors are critical for maintaining metabolic homeostasis. Therefore, we anticipated that Atp7b-/- mice would exhibit altered progression of diet-induced obesity, fatty liver, and insulin resistance. Following 10 weeks on a chow or Western-type diet (40% kcal fat), parameters of glucose and lipid homeostasis were measured. Hepatic metabolites were measured by LC-MS and correlated with transcriptomic data. Atp7b-/- mice fed a chow diet had lower fat mass and were more glucose tolerant than wild type (WT) littermate controls although body weights did not differ between genotypes. On Western diet, Atp7b-/- mice exhibited reduced adiposity and hepatic steatosis compared with WT controls. Atp7b-/- mice fed either diet were more insulin sensitive than WT controls; however, fasted Atp7b-/- mice exhibited hypoglycemia after administration of insulin, due to an impaired glucose counter-regulatory response, as evidenced by reduced hepatic glucose production. Coupling gene expression with metabolomic analyses, we observed striking changes in hepatic metabolic profiles in Atp7b-/- mice. In addition, the active phosphorylated form of AMP kinase was significantly increased in Atp7b-/- mice relative with WT controls. Alterations in hepatic metabolic profiles and nuclear receptor signaling were associated with improved glucose tolerance and insulin sensitivity, as well as impaired fasting glucose production in Atp7b-/- mice.
Project description:The goal of the study was find the gene expression of diverse signaling pathways altered in Atp7b-/- mice (murine WD) liver as compared to control mice and how LXR agonist treatment will improve/ameliorate WD phenotype in Atp7b-/- mice. Activation of LXR/RXR using synthetic LXR agonist ameliorates liver inflammation and fibrosis in murine WD by changing gene expression.
Project description:We report liver transcript profiling by RNA sequencing of Atp7b-/- and wild type mice at six weeks of age. Transcriptional network analysis of RNA-seq data reveals a highly interconnected network of transcriptional activators with over-representation of zinc-dependent and zinc-responsive transcription factors.
Project description:Purpose:Wilson's disease (WD) is a rare hereditary disorder due to ATP7B gene mutation, causing pathologic copper storage mainly in the liver and neurological systems. Hepatocyte transplantation showed therapeutic potential, however, this strategy is often hindered by a shortage of quality donor cells and by allogeneic immune rejection. Here we evaluate the function and efficacy of autologous reprogrammed, ATP7B gene-restored hepatocytes using a murine model of WD Mathods and Results: By reprogramming hepatocytes from ATP7B-/- mice with small molecules, sufficient liver progenitor cells (LPCs) are harvested. After lentivirus-mediated miniATP7B gene transfection and re-differentiation, functional LPC-ATP7B-Heps are developed. RNA-seq data show that compared with LPC-GFP-Heps with enrichment of genes mainly in pathways of oxidative stress and cell apoptosis, in LPC-ATP7B-Heps under high copper stress pathways for copper ion binding and cell proliferation are enriched. LPC-ATP7B-Heps transplantation into ATP7B-/- mice alleviates deposition of excess liver copper with its associated inflammation and fibrosis, comparable to those observed using normal primary hepatocytes at four months after transplantation. Conclusion: We establish the autologous reprogrammed, ATP7B gene restored LPC-ATP7B-Heps and further transplantation demonstrate alleviated copper accumulation in WD mice.
Project description:Wilson’s disease (WD) is a rare genetic disease caused by mutations in the ATP7B gene. These mutations impact the expression and/or function of the copper-transporting ATP7B protein, leading to massive toxic accumulation of copper in the liver and brain. Due to its low incidence and highly variable clinical presentations, WD is challenging to diagnose. Here, we explored the plasma proteome of the Atp7b-/- mouse, a genetic and phenotypic model of WD, to provide new insights into the pathogenic mechanisms of WD and discover potential biomarkers for WD diagnosis. A mass spectrometry (MS)-based proteomics workflow combining unbiased discovery analysis followed by targeted quantification was developed. Analysis of two independent groups of samples (discovery and validation cohorts) highlighted seven plasma proteins for which abundance was significantly modified (more than 2-fold) between Atp7b-/- mice and wild-type littermates. To assess the clinical significance and specificity of these seven proteins as potential biomarkers for WD, we adapted our targeted proteomics assay to allow the quantification of human orthologues in plasma from WD patients (treated with copper chelators), non-alcoholic steatohepatitis patients (disease-control group), and healthy donors. The plasma proteome changes observed in the Atp7b-/- mouse were not confirmed in treated WD patients, with the exception of alpha-1 antichymotrypsin, levels of which were decreased in WD patients compared to healthy individuals. Plasma ceruloplasmin was investigated in both the Atp7b-/- mouse model and human patients, and was found to be significantly decreased in the human form of WD only.
Project description:The H1069Q substitution in the liver-specific copper transporter ATP7B represents the major cause of Wilson disease. The mutated ATP7B undergoes rapid degradation in the endoplasmic reticulum (ER) and fails to reach copper excretion compartments thus causing severe copper toxicosis in patients. Modulating the ATP7B-H1069Q interactome was proposed as a rescue strategy but specific binding partners that might be targeted for mutant correction remain elusive. Here we try to identify a mutant-specific interactor for the pharmacological rescue of ATP7B-H1069Q.