Scheiber, Ivo* Dotaz Zobrazit nápovědu
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.
- MeSH
- ATPasy transportující měď genetika fyziologie MeSH
- duševní poruchy etiologie MeSH
- hematoencefalická bariéra MeSH
- hepatolentikulární degenerace etiologie genetika metabolismus MeSH
- lidé MeSH
- měď metabolismus MeSH
- mozek metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Copper is an essential trace metal that is required for the catalysis of several important cellular enzymes. However, since an excess of copper can also harm cells due to its potential to catalyze the generation of toxic reactive oxygen species, transport of copper and the cellular copper content are tightly regulated. This chapter summarizes the current knowledge on the importance of copper for cellular processes and on the mechanisms involved in cellular copper uptake, storage and export. In addition, we will give an overview on disturbances of copper homeostasis that are characterized by copper overload or copper deficiency or have been connected with neurodegenerative disorders.
- MeSH
- iontový transport MeSH
- měď * škodlivé účinky nedostatek metabolismus MeSH
- neurodegenerativní nemoci * chemicky indukované metabolismus patologie MeSH
- reaktivní formy kyslíku metabolismus MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Copper is an important trace element that is required for essential enzymes. However, due to its redox activity, copper can also lead to the generation of toxic reactive oxygen species. Therefore, cellular uptake, storage as well as export of copper have to be tightly regulated in order to guarantee sufficient copper supply for the synthesis of copper-containing enzymes but also to prevent copper-induced oxidative stress. In brain, copper is of importance for normal development. In addition, both copper deficiency as well as excess of copper can seriously affect brain functions. Therefore, this organ possesses ample mechanisms to regulate its copper metabolism. In brain, astrocytes are considered as important regulators of copper homeostasis. Impairments of homeostatic mechanisms in brain copper metabolism have been associated with neurodegeneration in human disorders such as Menkes disease, Wilson's disease and Alzheimer's disease. This review article will summarize the biological functions of copper in the brain and will describe the current knowledge on the mechanisms involved in copper transport, storage and export of brain cells. The role of copper in diseases that have been connected with disturbances in brain copper homeostasis will also be discussed.
- MeSH
- astrocyty fyziologie MeSH
- homeostáza MeSH
- lidé MeSH
- měď metabolismus MeSH
- mozek fyziologie patofyziologie MeSH
- neurodegenerativní nemoci patofyziologie MeSH
- neurony fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Iron and copper are essential elements for practically all living organisms. Their metabolism is frequently interconnected, and while copper is relatively abundant in the ocean, iron is often a limiting factor for the growth of many marine microorganisms. In the present study, we aimed to elucidate the metabolisms of copper and iron and the connection of both in the marine picoalga Ostreococcus tauri. We show that O. tauri adjusts its copper economy in response to copper deficiency by downregulation of the expression of plastocyanin in favor of cytochrome c oxidase without significant changes in growth and physiology. Copper deprivation leads to increased expression of copper transporting ATPase and proteins involved in tetrapyrrole synthesis, most likely to ensure higher turnover of chlorophyll and/or heme. Elucidation of the effect of copper on the incorporation of iron into O. tauri proteins led us to identify the major iron uptake mediating protein, Ot-Fea1, whose expression and binding of iron is copper dependent. Based on our investigation of the incorporation of iron into Ot-Fea1 and ferritin, we hypothesize that O. tauri possesses another Fea1-independent iron uptake system.
- MeSH
- ATPasy transportující měď metabolismus MeSH
- Chlorophyta metabolismus MeSH
- chloroplasty metabolismus MeSH
- měď metabolismus MeSH
- plastocyanin metabolismus MeSH
- rostlinné proteiny metabolismus MeSH
- transferin metabolismus MeSH
- železo metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Low iron bioavailability is a common feature of ocean surface water and therefore micro-algae developed original strategies to optimize iron uptake and metabolism. The marine picoeukaryotic green alga Ostreococcus tauri is a very good model for studying physiological and genetic aspects of the adaptation of the green algal lineage to the marine environment: it has a very compact genome, is easy to culture in laboratory conditions, and can be genetically manipulated by efficient homologous recombination. In this study, we aimed at characterizing the mechanisms of iron assimilation in O. tauri by combining genetics and physiological tools. Specifically, we wanted to identify and functionally characterize groups of genes displaying tightly orchestrated temporal expression patterns following the exposure of cells to iron deprivation and day/night cycles, and to highlight unique features of iron metabolism in O. tauri, as compared to the freshwater model alga Chalamydomonas reinhardtii. RESULTS: We used RNA sequencing to investigated the transcriptional responses to iron limitation in O. tauri and found that most of the genes involved in iron uptake and metabolism in O. tauri are regulated by day/night cycles, regardless of iron status. O. tauri lacks the classical components of a reductive iron uptake system, and has no obvious iron regulon. Iron uptake appears to be copper-independent, but is regulated by zinc. Conversely, iron deprivation resulted in the transcriptional activation of numerous genes encoding zinc-containing regulation factors. Iron uptake is likely mediated by a ZIP-family protein (Ot-Irt1) and by a new Fea1-related protein (Ot-Fea1) containing duplicated Fea1 domains. The adaptation of cells to iron limitation involved an iron-sparing response tightly coordinated with diurnal cycles to optimize cell functions and synchronize these functions with the day/night redistribution of iron orchestrated by ferritin, and a stress response based on the induction of thioredoxin-like proteins, of peroxiredoxin and of tesmin-like methallothionein rather than ascorbate. We briefly surveyed the metabolic remodeling resulting from iron deprivation. CONCLUSIONS: The mechanisms of iron uptake and utilization by O. tauri differ fundamentally from those described in C. reinhardtii. We propose this species as a new model for investigation of iron metabolism in marine microalgae.
- MeSH
- biologická adaptace MeSH
- Chlorophyta klasifikace genetika metabolismus MeSH
- Eukaryota genetika metabolismus MeSH
- fotoperioda MeSH
- fylogeneze MeSH
- fytoplankton genetika metabolismus MeSH
- fyziologický stres MeSH
- homeostáza MeSH
- měď metabolismus MeSH
- oxidace-redukce MeSH
- regulace genové exprese účinky záření MeSH
- rostlinné proteiny genetika metabolismus MeSH
- shluková analýza MeSH
- signální transdukce MeSH
- sloučeniny železa metabolismus MeSH
- stanovení celkové genové exprese MeSH
- transkriptom MeSH
- vysoce účinné nukleotidové sekvenování MeSH
- železo metabolismus MeSH
- Publikační typ
- časopisecké články MeSH