Wilson Disease: Intersecting DNA Methylation and Histone Acetylation Regulation of Gene Expression in a Mouse Model of Hepatic Copper Accumulation.

BACKGROUND & AIMS: The pathogenesis of Wilson disease (WD) involves hepatic and brain copper accumulation resulting from pathogenic variants affecting the ATP7B gene and downstream epigenetic and metabolic mechanisms. Prior methylome investigations in human WD liver and blood and in the Jackson Laboratory (Bar Harbor, ME) C3He-Atp7btx-j/J (tx-j) WD mouse model revealed an epigenetic signature of WD, including changes in histone deacetylase (HDAC) 5. We tested the hypothesis that histone acetylation is altered with respect to copper overload and aberrant DNA methylation in WD. METHODS: We investigated class IIa HDAC4 and HDAC5 and H3K9/H3K27 histone acetylation in tx-j mouse livers compared with C3HeB/FeJ (C3H) control in response to 3 treatments: 60% kcal fat diet, D-penicillamine (copper chelator), and choline (methyl group donor). Experiments with copper-loaded hepatoma G2 cells were conducted to validate in vivo studies. RESULTS: In 9-week tx-j mice, HDAC5 levels increased significantly after 8 days of a 60% kcal fat diet compared with chow. In 24-week tx-j mice, HDAC4/5 levels were reduced 5- to 10-fold compared with C3H, likely through mechanisms involving HDAC phosphorylation. HDAC4/5 levels were affected by disease progression and accompanied by increased acetylation. D-penicillamine and choline partially restored HDAC4/5 and H3K9ac/H3K27ac to C3H levels. Integrated RNA and chromatin immunoprecipitation sequencing analyses revealed genes regulating energy metabolism and cellular stress/development, which, in turn, were regulated by histone acetylation in tx-j mice compared with C3H mice, with Pparα and Pparγ among the most relevant targets. CONCLUSIONS: These results suggest dietary modulation of class IIa HDAC4/5, and subsequent H3K9/H3K27 acetylation/deacetylation can regulate gene expression in key metabolic pathways in the pathogenesis of WD.

Wilson disease, ABCC2 c.3972C > T polymorphism and primary liver cancers: suggestions from a familial cluster.

BACKGROUND: Polymorphisms in genes modulating xenobiotics metabolism, in particular the ABCC2 c.3972C > T single nucleotide polymorphism (SNP) at exon 28, have been suggested to increase primary liver cancer (PLC) risk. Conversely, the occurrence of PLCs in Wilson disease patients is a rare event, in contrast with the occurrence observed in other chronic liver diseases. Here we report the clinical case of five siblings carrying the ABCC2 c.3972C > T SNP; three of them were affected by Wilson disease and two brothers with Wilson disease also developed PLCs. METHODS: The presence of the ABCC2 c.3972C > T SNP was assessed by Sanger sequencing and the exposure of PLC risk factors by standardized questionnaires. RESULTS: Notably, PLCs occurred only in the two brothers with the ABCC2 c.3972C > T SNP and Wilson disease who resulted exposed to asbestos and cigarette smoking, but not in the other siblings with the ABCC2 c.3972C > T SNP, alone or in association with Wilson disease, not exposed to these carcinogens and/or to other known risk factors for PLCs. CONCLUSIONS: These findings suggest that ABCC2 c.3972C > T SNP and WD, also in association, may not represent a sufficient condition for PLC development, but that co-occurrence of further host/exogenous risk factors are needed to drive this process, reinforcing the notion that liver carcinogenesis is the result of a complex interplay between environmental and host genetic determinants. Due to the sporadic cases of this study and the paucity of data currently available in literature on this issue, future investigations in a larger population are needed to confirm our findings.

Implications of Manganese in Chronic Acquired Hepatocerebral Degeneration.

Neurological symptoms can be one of the over-riding symptoms in patients with liver cirrhosis. Patients can present with subtle changes in mood or neurological function due to hepatic encephalopathy (HE), to more severe presentations including stupor and coma. While HE, in its severe form, can be clinically easy to diagnose, more subtle forms may be more difficult to recognize. Other neurological diseases may indeed be overlooked in the context of cirrhosis or confuse the physician regarding the diagnosis. Chronic acquired hepatocerebral degeneration (CAHD) is an uncommon problem occurring in patients with cirrhosis characterised by a Parkinsonian-like neurological presentation with damage to the brain secondary to manganese (Mn) deposition. Here we describe a case of a patient with a neurological presentation of liver disease with a review of the current CAHD literature. In conclusion, CAHD is a rare condition occurring in liver cirrhosis that should always be considered in patients with neurological manifestations of chronic liver disease.

The Function of ATPase Copper Transporter ATP7B in Intestine.

BACKGROUND & AIMS: Wilson disease is a disorder of copper (Cu) misbalance caused by mutations in ATP7B. ATP7B is highly expressed in the liver-the major site of Cu accumulation in patients with Wilson disease. The intestine also expresses ATP7B, but little is known about the contribution of intestinal ATP7B to normal intestinal copper homeostasis or to Wilson disease manifestations. We characterized the role of ATP7B in mouse intestinal organoids and tissues. METHODS: We collected intestinal tissues from ATP7B-knockout (Atp7b-/-) and control mice, and established 3-dimensional enteroids. Immunohistochemistry and x-ray fluorescence were used to characterize the distribution of ATP7B and Cu in tissues. Electron microscopy, histologic analyses, and immunoblotting were used to determine the effects of ATP7B loss. Enteroids derived from control and ATP7B-knockout mice were incubated with excess Cu or with Cu-chelating reagents; effects on cell fat content and ATP7B levels and localization were determined by fluorescent confocal microscopy. RESULTS: ATP7B maintains a Cu gradient along the duodenal crypt-villus axis and buffers Cu levels in the cytosol of enterocytes. These functions are mediated by rapid Cu-dependent enlargement of ATP7B-containing vesicles and increased levels of ATP7B. Intestines of Atp7b-/- mice had reduced Cu storage pools in intestine, Cu depletion, accumulation of triglyceride-filled vesicles in enterocytes, mislocalization of apolipoprotein B, and loss of chylomicrons. In primary 3-dimensional enteroids, administration of excess Cu or Cu chelators impaired assembly of chylomicrons. CONCLUSIONS: ATP7B regulates vesicular storage of Cu in mouse intestine. ATP7B buffers Cu levels in enterocytes to maintain a range necessary for formation of chylomicrons. Misbalance of Cu and lipid in the intestine could account for gastrointestinal manifestations of Wilson disease.

Acquired hepatocerebral degeneration (AHD): a peculiar neurological impairment in advanced chronic liver disease.

We discuss the case of a rare and often unrecognized neurologic syndrome, called Acquired Hepatocerebral Degeneration (AHD), observed in patients with advanced liver disease and portosystemic shunts. The clinical manifestations can be very heterogeneous and in our case included a combination of cerebellar and extrapyramidal signs, arisen in a period of few days. Brain Magnetic Resonance Imaging (MRI) showed, in T1-weighted images, diffuse bilateral hyper intensities in basal ganglia and biemispheric brain and cerebellar cortices, resembling paramagnetic deposits. No other neurological impairments, like stroke, infection or neoplasia, were found. It was excluded an episode of acute hepatic encephalopathy. We also ruled out Wilsonian degeneration, iron overload and autoimmune encephalitis and we lastly found high manganese levels as the possible cause of the brain paramagnetic deposits. Even though either serum Mn determination or its accumulation in the brain are not specific for AHD, however the chronic and progressively worsening of the neurological manifestations advocated a degenerative condition, possibly AHD. We finally opted for the early restoration of liver function by OLT, and we observed complete clinical symptoms' resolution and partial MRI reversal after a follow up of 6 months.

Biological role of copper as an essential trace element in the human organism.

This paper presents an overview of the physiological properties of copper (Cu), an essential trace element playing an important role in the human metabolism, primarily as a cofactor of many metalloenzymes. The maintenance of Cu homeostasis is required for proper functioning of the human body. However, when the disturbance of Cu homeostasis occurs, strong pathological manifestations may develop. Wilsons disease and idiopathic toxicosis are examples of severe chronic liver diseases that are the results of genetic predisposition to the hepatic accumulation of copper. Conversely, congenital Menkes disease is manifested as serious Cus nutritional deficiency. Although Cu is necessary for many life processes, it is also a powerful weapon used since the ancient times against many microorganisms. Finally, the theories of Cu antimicrobial and antiviral mechanisms of action are summarized, including contemporary and potential future utilizations in medical and non-medical fields of human life. Key words: copper metalloenzymes copper toxicity copper deficiency copper-related diseases copper applications.

A Study of Extrapyramidal Manifestations Accompanying Decompensated Viral Hepatic Cirrhosis Patients.

BACKGROUND: Despite the high prevalence of viral hepatic cirrhosis all over the world, the characteristic motor features of related Parkinsonism (extrapyramidal manifestations) are not well described. The current study aimed to characterize such disorder in a sample of Egyptian patients with chronic viral liver disease (CLD), and their clinical correlates. METHODS: Ninety-six (96) patients with CLD were examined for the presence of extrapyramidal signs. Parkinsonism was assessed using the UPDRS-III scale and its sub scores. Ataxia and dystonia were also assessed by related scales. Patients with Parkinsonism were compared to other patients and correlations with clinical features of CLD were done. RESULTS: The clinical diagnosis of extrapyramidal manifestations was justified in 57 patients (59.4%) with predominant akinetic rigid syndrome (ARS) (87.7%). Bradykinesia and axial features were the most frequent signs (89.5% and 70.2%, respectively). 38.6% of patients had postural tremors, whereas only 3.5% had rest tremors. Gait and postural abnormalities were detected in 38.6% and 36.8% respectively. Parkinsonism was associated with advanced hepatic cirrhosis (p=0.02) and increased episodes of hepatic encephalopathy (HE) (p=0.006). Severity of parkinsonian features was correlated to patients' age, age of onset of CLD and rapid progression, while impaired speech and gait were rather correlated to a number of episodes of HE. CONCLUSION: Advanced viral cirrhosis is associated with high prevalence of parkinsonism that is characterized by symmetrical ARS with frequent axial features, postural tremor, gait and postural impairment. Severity of these signs is correlated to age, age of onset, rapid progression and frequency of HE.

Genetic and environmental modifiers of Wilson disease.

Wilson disease (WD) is characterized by remarkable variety in its phenotypic presentation. Patients with WD can present with hepatic, neurologic, and psychiatric symptoms combined in different and unpredictable ways. Importantly, no convincing phenotype-genotype correlation has ever been identified, opening the possibility that other genes, aside from ATPase copper-transporting beta (ATP7B), are involved in the pathogenesis of this condition. In addition, modifier genes, or genes that can affect the expression of other genes, may be involved. Clinical and basic science data indicate that environmental and dietary factors can potentially modify gene expression in WD and, consequently, its clinical presentation and course. In particular, previously studied genes include copper metabolism domain-containing 1 (COMMD1), antioxidant 1 copper chaperone (ATOX1), X-linked inhibitor of apoptosis (XIAP), apolipoprotein E (APOE), hemochromatosis (HFE), and 5,10-methylenetetrahydrofolate reductase (MTHFR). Dietary factors include iron and methyl group donors which could affect methionine metabolism and epigenetic mechanisms of gene expression regulation. Most of the work conducted in this field is in its initial stages but it has the potential to change the diagnosis and treatment of WD.

Pathogenesis of Wilson disease.

Wilson disease is an autosomal-recessive disorder originating from a genetic defect in the copper-transporting ATPase ATP7B that is required for biliary copper secretion and loading of ceruloplasmin with copper. Impaired ATP7B function in Wilson disease results in excessive accumulation of copper in liver, brain, and other tissues. Toxic copper deposits may induce oxidative stress, modify expression of genes, directly inhibit proteins, and impair mitochondrial function, leading to hepatic, neuropsychiatric, renal, musculoskeletal, and other symptoms. Hepatocyte dysfunction initially manifests as steatosis and later may progress to other hepatic phenotypes such as acute liver failure, hepatitis, and fibrosis. In the brain, copper accumulates in astrocytes, leading to impairment of the blood-brain barrier and consequent damage to neurons and oligodendrocytes. Basal ganglia and brainstem are the brain regions with highest susceptibility to copper toxicity and their lesions lead to various combinations of movement and psychiatric disorders. This chapter will give an overview of the essential requirement of copper for biologic processes and the molecular mechanisms employed by cells to maintain their copper levels in a proper range. We will specify the physiologic functions of ATP7B and the consequences of its dysfunction and summarize the current knowledge on the pathogenesis of liver and neuropsychiatric disease. Finally, we will describe the consequences of copper overload in Wilson disease in other tissues.

In Vivo Modeling of the Pathogenic Effect of Copper Transporter Mutations That Cause Menkes and Wilson Diseases, Motor Neuropathy, and Susceptibility to Alzheimer's Disease.

Copper is an essential biometal, and several inherited diseases are directly associated with a disruption to normal copper homeostasis. The best characterized are the copper deficiency and toxicity disorders Menkes and Wilson diseases caused by mutations in the p-type Cu-ATPase genes ATP7A and ATP7B, respectively. Missense mutations in the C-terminal portion of ATP7A have also been shown to cause distal motor neuropathy, whereas polymorphisms in ATP7B are associated with increased risk of Alzheimer's disease. We have generated a single, in vivo model for studying multiple pathogenic mutations in ATP7 proteins using Drosophila melanogaster, which has a single orthologue of ATP7A and ATP7B. Four pathogenic ATP7A mutations and two ATP7B mutations were introduced into a genomic ATP7 rescue construct containing an in-frame C-terminal GFP tag. Analysis of the wild type ATP7-GFP transgene confirmed that ATP7 is expressed at the basolateral membrane of larval midgut copper cells and that the transgene can rescue a normally early lethal ATP7 deletion allele to adulthood. Analysis of the gATP7-GFP transgenes containing pathogenic mutations showed that the function of ATP7 was affected, to varying degrees, by all six of the mutations investigated in this study. Of particular interest, the ATP7BK832R Alzheimer's disease susceptibility allele was found, for the first time, to be a loss of function allele. This in vivo system allows us to assess the severity of individual ATP7A/B mutations in an invariant genetic background and has the potential to be used to screen for therapeutic compounds able to restore function to faulty copper transport proteins.

Etiology of chronic liver diseases in the Northwest of Italy, 1998 through 2014.

AIM: To assess the etiology of chronic liver diseases (CLD) from 1998 to 2014 at the outpatient clinic of Gastroenterology of the main hospital in Northwest of Italy among those dedicated to hepatology. METHODS: A random sample of charts of patients referred to for increased liver enzymes between January 1998 and December 2006, and between January 2012 and December 2014 were reviewed. Etiology search included testing for hepatitis B virus (HBV), hepatitis C virus (HCV), autoimmune hepatitis, primary biliary cirrhosis, Wilson's disease and hereditary hemocromatosis. A risky alcohol consumption was also considered. Non-alcoholic fatty liver disease (NAFLD) was diagnosed in patients with histological and/or ultrasound evidence of steatosis/steatohepatitis, and without other causes of CLD. RESULTS: The number of patients included was 1163. Of them, 528 (45%) had positivity for HCV and 85 (7%) for HBV. Among the virus-free patients, 417 (36%) had metabolic disorders whereas the remaining had history of alcohol abuse, less prevalent causes of CLD or concomitant conditions. In comparison to 1998-2000 (41%), a reduction of HCV alone-related cases was detected during the periods 2001-2003 (35%, OR = 0.75, 95%CI: 0.53-1.06), 2004-2006 (33%, OR = 0.70, 95%CI: 0.50-0.97) and 2012-2014 (31%, OR = 0.64, 95%CI: 0.46-0.91). On the contrary, in comparison to 1998-2000 (31%), metabolic-alone disorders increased in the period 2004-2006 (39%, OR = 1.37, 95%CI: 0.99-1.91) and 2012-2014 (41%, OR = 1.53, 95%CI: 1.09-2.16). The other etiologies remained stable. The increase of incidence of metabolic-alone etiology during the period 2004-2006 and 2012-2014 tended to be higher in older patients (≥ 50 years) compared to younger (P = 0.058). CONCLUSION: In the Northwest of Italy, during this study period, the prevalence of HCV infection decreased notably whereas that of NAFLD increased.

A systems biology approach reveals new endoplasmic reticulum-associated targets for the correction of the ATP7B mutant causing Wilson disease.

Copper (Cu) is an important trace element required for the activity of essential enzymes. However, excess Cu compromises the redox balance in cells and tissues causing serious toxicity. The process of disposal of excess Cu from organisms relies on the activity of Cu-transporting ATPase ATP7B. ATP7B is mainly expressed in liver hepatocytes where it sequesters the potentially toxic metal and mediates its excretion into the bile. Mutations in the ATP7B gene cause Wilson disease (WD), which is characterized by the accumulation of toxic Cu in the liver due to the scarce expression of ATP7B as well as the failure of ATP7B mutants to pump Cu and/or traffic to the Cu-excretion sites. The most frequent ATP7B mutant, H1069Q, still presents a significant Cu-transporting activity, but undergoes retention within the endoplasmic reticulum (ER) where the mutant is rapidly degraded. Expression of this ATP7B mutant has been recently reported to activate the p38 and JNK stress kinase pathways, which, in turn, trigger quality control mechanisms leading to the arrest of ATP7B-H1069Q in the ER and to the acceleration of its degradation. However, the main molecular players operating in these p38/JNK-dependent ER quality control pathways remain to be discovered. By using a combination of RNAseq, bioinformatics and RNAi approaches, we found a cluster of ER quality control genes whose expression is controlled by p38 and JNK and is required for the efficient retention of the ATP7B-H1069Q mutant in the ER. Silencing these genes reduced the accumulation of the ATP7B mutant in the ER and facilitated the mutant sorting and export to the Golgi and post-Golgi copper excretion sites. In sum, our findings reveal the ER-associated genes that could be utilized for the correction of ATP7B mutants and, hence, for the normalization of Cu homeostasis in Wilson disease.

A lady with NASH and choreoathetosis.

We describe a case of acquired hepatocerebral degeneration (AHD) presenting with confusion and worsening memory problems since her discharge from the gastroenterology units. Cases of AHD are rare and are frequently confused with hepatic encephalopathy and Wilson's disease. There are no proven pharmacological therapies for AHD. Information regarding the effect of orthotopic liver transplant on AHD is limited and conflicting. Most patients eventually die from the systemic complications of cirrhotic liver failure including infection, hepatic coma and hepatocellular carcinoma.

Wilson disease and other neurodegenerations with metal accumulations.

Trace elements, such as iron, copper, manganese, and calcium, which are essential constituents necessary for cellular homeostasis, become toxic when present in excess quantities. In this article, we describe disorders arising from endogenous dysregulation of metal homeostasis leading to their tissue accumulation. Although subgroups of these diseases lead to regional brain metal accumulation, mostly in globus pallidus, which is susceptible to accumulate divalent metal ions, other subgroups cause systemic metal accumulation affecting the whole brain, liver, and other parenchymal organs. The latter group comprises Wilson disease, manganese transporter deficiency, and aceruloplasminemia and responds favorably to chelation treatment.

Biological consequences of zinc deficiency in the pathomechanisms of selected diseases.

From many points of view, zinc is one of the most important trace elements in biological systems. Many articles describe the well-known role of this metal in human physiology and pathophysiology, but in the related literature, there is a lack of current and reliable reviews of the role of zinc deficiency in many diseases. In this article, we describe the role of zinc deficiency in the oxidative stress control, immune response, proliferation, and pathogenesis and pathophysiology of selected diseases such as depression, cardiovascular diseases, diabetes mellitus, Alzheimer's disease, and Wilson's disease.