Chronic myeloid leukemia (CML) is a malignant hematopoietic disorder distinguished by the presence of a BCR‑ABL1 fused oncogene with constitutive kinase activity. Targeted CML therapy by specific tyrosine kinase inhibitors (TKIs) leads to a marked improvement in the survival of the patients and their quality of life. However, the development of resistance to TKIs remains a critical issue for a subset of patients. The most common cause of resistance are numerous point mutations in the BCR‑ABL1 gene, followed by less common mutations and multiple mutation-independent mechanisms. Recently, exosomes, which are extracellular vesicles excreted from normal and tumor cells, have been associated with drug resistance and cancer progression. The aim of the present study was to characterize the exosomes released by imatinib‑resistant K562 (K562IR) cells. The K562IR‑derived exosomes were internalized by imatinib‑sensitive K562 cells, which thereby increased their survival in the presence of 2 µM imatinib. The exosomal cargo was subsequently analyzed to identify resistance‑associated markers using a deep label‑free quantification proteomic analysis. There were >3,000 exosomal proteins identified of which, 35 were found to be differentially expressed. From this, a total of 3, namely the membrane proteins, interferon‑induced transmembrane protein 3, CD146 and CD36, were markedly upregulated in the exosomes derived from the K562IR cells, and exhibited surface localization. The upregulation of these proteins was verified in the K562IR exosomes, and also in the K562IR cells. Using flow cytometric analysis, it was possible to further demonstrate the potential of CD146 as a cell surface marker associated with imatinib resistance in K562 cells. Taken together, these results suggested that exosomes and their respective candidate surface proteins could be potential diagnostic markers of TKI drug resistance in CML therapy.

• MeSH
• antigen CD146 metabolismus   MeSH
• antigeny CD36 metabolismus   MeSH
• apoptóza účinky léků   MeSH
• bcr-abl fúzní proteiny antagonisté a inhibitory   genetika   MeSH
• buňky K562 MeSH
• chemorezistence MeSH
• chronická myeloidní leukemie farmakoterapie   genetika   patologie   MeSH
• exozómy účinky léků   metabolismus   MeSH
• imatinib mesylát farmakologie   terapeutické užití   MeSH
• inhibitory proteinkinas farmakologie   terapeutické užití   MeSH
• lidé MeSH
• membránové proteiny metabolismus   MeSH
• nádorové buněčné linie MeSH
• proteiny vázající RNA metabolismus   MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články 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: Up to 50% of patients with chronic heart failure (HF) have systemic iron deficiency, which contributes to symptoms and poor prognosis. Myocardial iron deficiency (MID) in HF patients has been recently documented, but its causes and consequences are unknown. The goal of our study was to address these questions in a well-defined rat HF model induced by volume overload due to aorto-caval fistula. METHODS: Modulation of dietary iron content in a rat model of HF has been used to address how iron status affects cardiac iron levels, heart structure and function, and how the presence of HF affects cardiac expression of hepcidin and other iron-related genes. RESULTS: MID developed in the rat model of heart failure. Iron supplementation did not normalize the myocardial iron content; however, it improved survival of HF animals compared to animals fed diet with normal iron content. We observed marked upregulation of hepcidin mRNA expression in HF animals, which was not associated with systemic or cardiac iron levels but strongly correlated with markers and parameters of heart injury. Identical iron-independent pattern was observed for expression of several iron-related genes. CONCLUSIONS: MID is not caused by defective iron absorption or decreased systemic iron levels, but rather by intrinsic myocardial iron deregulation. Altered cardiac expression of hepcidin and other iron-related genes is driven by iron-independent stimuli in the failing heart. GENERAL SIGNIFICANCE: Understanding of the causes and consequences of MID is critical for finding strategies how to improve cardiac iron stores and in HF patients.

• MeSH
• aplikace orální MeSH
• deficit železa MeSH
• dietní železo aplikace a dávkování   MeSH
• hepcidiny metabolismus   MeSH
• homeostáza MeSH
• krysa rodu rattus MeSH
• modely nemocí na zvířatech * MeSH
• myokard chemie   metabolismus   MeSH
• potkani Sprague-Dawley MeSH
• srdeční selhání metabolismus   MeSH
• železo metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Iron is an essential biogenic element for both prokaryotic and eukaryotic cells. In humans iron is present in hundreds of different metalloproteins. The peptide hormone hepcidin serves as a master regulator of iron homeostasis on the level of single cells and whole organism - by altering cell surface expression of cellular iron exporter - protein ferroportin. Altered levels of extracellular hepcidin lead to pathological conditions such as hemochromatosis and iron loading or, on the other side, iron restrictive anemias. Therapeutic modulation of hepcidin is a new and promising approach to treatment of these conditions. In this review, a summary of the current knowledge of hepcidin function, regulation and pathological involvements are provided, followed by a section covering the therapeutic potential of hepcidin and the current strategies how to modulate its levels and biological functions for therapeutic purposes.

• MeSH
• hepcidiny farmakologie   terapeutické užití   MeSH
• homeostáza účinky léků   MeSH
• lidé MeSH
• proteiny přenášející kationty metabolismus   MeSH
• železo metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Hepcidin regulates iron metabolism by down-regulating ferroportin-1 (Fpn1). We demonstrated that hepcidin is complexed to the blood transport protein, α2-macroglobulin (α2M) (Peslova, G., Petrak, J., Kuzelova, K., Hrdy, I., Halada, P., Kuchel, P. W., Soe-Lin, S., Ponka, P., Sutak, R., Becker, E., Huang, M. L., Suryo Rahmanto, Y., Richardson, D. R., and Vyoral, D. (2009) Blood 113, 6225-6236). However, nothing is known about the mechanism of hepcidin binding to α2M or the effects of the α2M·hepcidin complex in vivo. We show that decreased Fpn1 expression can be mediated by hepcidin bound to native α2M and also, for the first time, hepcidin bound to methylamine-activated α2M (α2M-MA). Passage of high molecular weight α2M·hepcidin or α2M-MA·hepcidin complexes (≈725 kDa) through a Sephadex G-25 size exclusion column retained their ability to decrease Fpn1 expression. Further studies using ultrafiltration indicated that hepcidin binding to α2M and α2M-MA was labile, resulting in some release from the protein, and this may explain its urinary excretion. To determine whether α2M-MA·hepcidin is delivered to cells via the α2M receptor (Lrp1), we assessed α2M uptake and Fpn1 expression in Lrp1(-/-) and Lrp1(+/+) cells. Interestingly, α2M·hepcidin or α2M-MA·hepcidin demonstrated similar activities at decreasing Fpn1 expression in Lrp1(-/-) and Lrp1(+/+) cells, indicating that Lrp1 is not essential for Fpn1 regulation. In vivo, hepcidin bound to α2M or α2M-MA did not affect plasma clearance of α2M/α2M-MA. However, serum iron levels were reduced to a significantly greater extent in mice treated with α2M·hepcidin or α2M-MA·hepcidin relative to unbound hepcidin. This effect could be mediated by the ability of α2M or α2M-MA to retard kidney filtration of bound hepcidin, increasing its half-life. A model is proposed that suggests that unlike proteases, which are irreversibly bound to activated α2M, hepcidin remains labile and available to down-regulate Fpn1.

• MeSH
• alfa-makroglobuliny genetika   metabolismus   MeSH
• biologické modely * MeSH
• buněčné linie MeSH
• hepcidiny krev   genetika   MeSH
• LDL-receptory genetika   metabolismus   MeSH
• lidé MeSH
• multiproteinové komplexy krev   genetika   MeSH
• myši knockoutované MeSH
• myši MeSH
• nádorové supresorové proteiny genetika   metabolismus   MeSH
• protein 1 související s LDL-receptory genetika   metabolismus   MeSH
• proteiny přenášející kationty biosyntéza   genetika   MeSH
• regulace genové exprese fyziologie   MeSH
• železo krev   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The peptide hormone hepcidin functions as a negative regulator of intestinal Fe absorption and Fe recycling. Since its discovery as a systemic negative regulator of Fe metabolism, hepcidin has attracted enormous interest as a potential drug for the treatment and/or prevention of several forms of Fe overload. We therefore tested whether multiple doses of intraperitoneally administered synthetic renatured hepcidin can prevent hepatic Fe loading in mice concurrently fed an Fe-rich diet, and whether the same treatment affects hepatic Fe stores in mice fed a normal diet. Cohorts of male mice were fed either a normal defined diet (180 parts per million Fe) or an Fe-rich diet (the same diet supplemented with 2 % carbonyl iron for 2 weeks). Concurrently, half of the animals in each diet group received 100 μg of renatured hepcidin intraperitoneally every 12 h, for the same 2-week period. The second half of the animals received PBS only. The renatured synthetic hepcidin demonstrated biological activity by significantly decreasing transferrin saturation, which lasted for up to 24 h after a single hepcidin dose. However, the 14 d intraperitoneal hepcidin therapy did not prevent hepatic Fe overload in mice fed the Fe-rich diet, nor did it affect hepatic Fe stores in mice fed the normal diet. Both hepcidin agonists and antagonists are expected to have broad therapeutic potential. The absence of an effect of biologically active hepcidin on hepatic Fe loading shows the need for thorough future studies on the hepcidin regulation of Fe absorption and tissue distribution.

• MeSH
• dieta MeSH
• dietní železo aplikace a dávkování   MeSH
• injekce intraperitoneální MeSH
• kationické antimikrobiální peptidy aplikace a dávkování   terapeutické užití   MeSH
• krmivo pro zvířata MeSH
• lékové postižení jater prevence a kontrola   MeSH
• myši MeSH
• přetížení železem prevence a kontrola   MeSH
• transferin MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Železo je nezastupitelný biogenní prvek, jako katalytická součást mnoha metaloproteinů se uplatňuje téměř ve všech biochemických drahách, je však také schopno iniciovat tvorbu škodlivých volných radikálů. Tento přehledový článek shrnuje nové poznatky o mechanizmech, regulacích a poruchách absorpce a transportu železa.

Iron is an indispensable element. As a catalytical center in many Fe metalloproteins it participates in almost all biochemical pathways. This element, however is able to initiate the generation of toxic free radicals. This review article summarizes the available knowledge on the mechanisms, regulations and disorders of iron absorption, transport and storage.

• Klíčová slova
• hepcidin,
• MeSH
• anemie z nedostatku železa etiologie   patofyziologie   MeSH
• ferritiny fyziologie   metabolismus   MeSH
• hemoproteiny fyziologie   metabolismus   MeSH
• kationické antimikrobiální peptidy metabolismus   MeSH
• lidé MeSH
• poruchy metabolismu železa * etiologie   patofyziologie   MeSH
• přetížení železem etiologie   patofyziologie   MeSH
• proteiny obsahující železo a síru fyziologie   krev   metabolismus   MeSH
• proteiny regulující obsah železa MeSH
• proteiny vázající železo fyziologie   metabolismus   MeSH
• transferin fyziologie   metabolismus   MeSH
• železo * chemie   krev   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH
• přehledy MeSH

Myotonic dystrophy kinase-related Cdc42-binding kinase alpha (MRCKalpha, formally known as CDC42BPA) is a serine/threonine kinase that can regulate actin/myosin assembly and activity. Recently, it has been shown that it possesses a functional iron responsive element (IRE) in the 3'-untranslated region (UTR) of its mRNA, suggesting that it may be involved in iron metabolism. Here we report that MRCKalpha protein expression is also regulated by iron levels; MRCKalpha colocalizes with transferrin (Tf)-loaded transferrin receptors (TfR), and attenuation of MRCKalpha expression by a short hairpin RNA silencing construct leads to a significant decrease in Tf-mediated iron uptake. Our results thus indicate that MRCKalpha takes part in Tf-iron uptake, probably via regulation of Tf-TfR endocytosis/endosome trafficking that is dependent on the cellular cytoskeleton. Regulation of the MRCKalpha activity by intracellular iron levels could thus represent another molecular feedback mechanism cells could use to finely tune iron uptake to actual needs.

• MeSH
• endocytóza MeSH
• endozomy enzymologie   MeSH
• HeLa buňky MeSH
• lidé MeSH
• malá interferující RNA genetika   MeSH
• protein-serin-threoninkinasy genetika   metabolismus   MeSH
• receptory transferinu metabolismus   MeSH
• RNA interference MeSH
• transferin metabolismus   MeSH
• železo metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Hepcidin is a major regulator of iron metabolism. Hepcidin-based therapeutics/diagnostics could play roles in hematology in the future, and thus, hepcidin transport is crucial to understand. In this study, we identify alpha2-macroglobulin (alpha2-M) as the specific hepcidin-binding molecule in blood. Interaction of 125I-hepcidin with alpha2-M was identified using fractionation of plasma proteins followed by native gradient polyacrylamide gel electrophoresis and mass spectrometry. Hepcidin binding to nonactivated alpha2-M displays high affinity (Kd 177 +/- 27 nM), whereas hepcidin binding to albumin was nonspecific and displayed nonsaturable kinetics. Surprisingly, the interaction of hepcidin with activated alpha2-M exhibited a classical sigmoidal binding curve demonstrating cooperative binding of 4 high-affinity (Kd 0.3 microM) hepcidin-binding sites. This property probably enables efficient sequestration of hepcidin and its subsequent release or inactivation that may be important for its effector functions. Because alpha2-M rapidly targets ligands to cells via receptor-mediated endocytosis, the binding of hepcidin to alpha2-M may influence its functions. In fact, the alpha2-M-hepcidin complex decreased ferroportin expression in J774 cells more effectively than hepcidin alone. The demonstration that alpha2-M is the hepcidin transporter could lead to better understanding of hepcidin physiology, methods for its sensitive measurement and the development of novel drugs for the treatment of iron-related diseases.

• MeSH
• 2D gelová elektroforéza MeSH
• alfa-makroglobuliny metabolismus   MeSH
• gelová chromatografie MeSH
• kationické antimikrobiální peptidy metabolismus   MeSH
• kultivované buňky MeSH
• lidé MeSH
• makrofágy cytologie   metabolismus   MeSH
• monocyty cytologie   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• proteiny přenášející kationty metabolismus   MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• vazba proteinů MeSH
• western blotting MeSH
• železo metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

After reading many 2-DE-based articles featuring lists of the differentially expressed proteins, one starts experiencing a disturbing deja vu. The same proteins seem to predominate regardless of the experiment, tissue or species. To quantify the occurrence of individual differentially expressed proteins in 2-DE experiment reports, we compiled the identities of differentially expressed proteins identified in human, mouse, and rat tissues published in three recent volumes of Proteomics and calculated the appearance of the most predominant proteins in the dataset. The most frequently identified protein is a highly abundant glycolytic enzyme enolase 1, differentially expressed in nearly every third experiment on both human and rodent tissues. Heat-shock protein 27 (HSP27) and heat-shock protein 60 (HSP60) were differentially expressed in about 30 percent of human and rodent samples, respectively. Considering protein families as units, keratins and peroxiredoxins are the most frequently identified molecules, with at least one member of the group being differentially expressed in about 40 percent of all experiments. We suggest that the frequent identification of these proteins must be considered in the interpretation of any 2-DE studies. We consider if these commonly observed changes represent common cellular stress responses or are a reflection of the technical limitations of 2-DE.

• MeSH
• 2D gelová elektroforéza MeSH
• financování organizované MeSH
• fosfopyruváthydratasa biosyntéza   MeSH
• genetická transkripce MeSH
• glyceraldehyd-3-fosfátdehydrogenasa (fosforylační) metabolismus   MeSH
• krysa rodu rattus MeSH
• lidé MeSH
• multigenová rodina MeSH
• myši MeSH
• nádorové proteiny biosyntéza   MeSH
• peroxiredoxiny metabolismus   MeSH
• proteiny tepelného šoku HSP27 MeSH
• proteiny teplotního šoku biosyntéza   MeSH
• proteomika metody   MeSH
• regulace genové exprese MeSH
• stanovení celkové genové exprese MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• myši MeSH
• zvířata MeSH