Hepcidin deficiency leads to iron overload by increased dietary iron uptake and iron release from storage cells. The most frequent mutation in Hfe leads to reduced hepcidin expression and thereby causes iron overload. Recent findings suggested that HFE activates hepcidin expression predominantly via the BMP type I receptor ALK3. Here, we investigated whether HFE exclusively utilizes ALK3 or other signaling mechanisms also. We generated mice with double deficiency of Hfe and hepatocyte-specific Alk3 and compared the iron overload phenotypes of these double knockout mice to single hepatocyte-specific Alk3 deficient or Hfe knockout mice. Double Hfe-/-/hepatic Alk3fl/fl;Alb-Cre knockouts develop a similar iron overload phenotype compared to single hepatocyte-specific Alk3 deficient mice hallmarked by serum iron levels, tissue iron content and hepcidin levels of similar grades. HFE protein levels were increased in Alk3fl/fl;Alb-Cre mice compared to Alk3fl/fl mice, which was caused by iron overload - and not by Alk3 deficiency. The data provide evidence by genetic means that 1. HFE exclusively uses the BMP type I receptor ALK3 to induce hepcidin expression and 2. HFE protein expression is induced by iron overload, which further emphasizes the iron sensing function of HFE.

• MeSH
• hepcidiny * genetika   MeSH
• histokompatibilita - antigeny třídy I genetika   MeSH
• játra metabolismus   MeSH
• myši knockoutované MeSH
• myši MeSH
• přetížení železem * genetika   MeSH
• protein hemochromatózy genetika   MeSH
• receptory morfogenetických kostních proteinů typu I MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: Sideroblastic anemia represents a heterogeneous group of inherited or acquired diseases with disrupted erythroblast iron utilization, ineffective erythropoiesis, and variable systemic iron overload. In a cohort of 421 patients with multisystem mitochondrial diseases, refractory anemia was found in 8 children. RESULTS: Five children had sideroblastic anemia with increased numbers of ring sideroblasts >15%. Two of the children had a fatal course of MLASA1 syndrome (mitochondrial myopathy, lactic acidosis, and sideroblastic anemia [SA]) due to a homozygous, 6-kb deletion in the PUS1 gene, part of the six-member family of pseudouridine synthases (pseudouridylases). Large homozygous deletions represent a novel cause of presumed PUS1-loss-of-function phenotype. The other three children with SA had Pearson syndrome (PS) due to mtDNA deletions of 4 to 8 kb; two of these children showed early onset of PS and died due to repeated sepsis; the other child had later onset of PS and survived as the hematological parameters normalized and the disease transitioned to Kearns-Sayre syndrome. In addition, anemia without ring sideroblasts was found in three other patients with mitochondrial disorders, including two children with later onset of PS and one child with failure to thrive, microcephaly, developmental delay, hypertrophic cardiomyopathy, and renal tubular acidosis due to the heterozygous mutations c.610A>G (p.Asn204Asp) and c.674C>T (p.Pro225Leu) in the COX10 gene encoding the cytochrome c oxidase assembly factor. CONCLUSIONS: Sideroblastic anemia was found in fewer than 1.2% of patients with multisystem mitochondrial disease, and it was usually associated with an unfavorable prognosis.

• MeSH
• acyl-CoA-dehydrogenasa s dlouhým řetězcem nedostatek   genetika   metabolismus   MeSH
• dítě MeSH
• lidé MeSH
• mitochondriální nemoci * genetika   metabolismus   patologie   MeSH
• nemoci svalů * genetika   metabolismus   patologie   MeSH
• předškolní dítě MeSH
• přetížení železem * genetika   metabolismus   patologie   MeSH
• sideroblastická anemie * genetika   metabolismus   patologie   MeSH
• syndrom MELAS * genetika   metabolismus   MeSH
• vrozené poruchy metabolismu tuků * genetika   metabolismus   patologie   MeSH
• vrozené syndromy selhání kostní dřeně MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Pyruvate kinase (PK) deficiency is an iron-loading anaemia characterized by chronic haemolysis, ineffective erythropoiesis and a requirement for blood transfusion in most cases. We studied 11 patients from 10 unrelated families and found nine different disease-causing PKLR mutations. Two of these mutations - the point mutation c.878A>T (p.Asp293Val) and the frameshift deletion c.1553delG (p.(Arg518Leufs*12)) - have not been previously described in the literature. This frameshift deletion was associated with an unusually severe phenotype involving neonatal hyperferritinaemia that is not typical of PK deficiency. No disease-causing mutations in genes associated with haemochromatosis could be found. Inappropriately low levels of hepcidin with respect to iron loading were detected in all PK-deficient patients with increased ferritin, confirming the predominant effect of accelerated erythropoiesis on hepcidin production. Although the levels of a putative hepcidin suppressor, growth differentiation factor-15, were increased in PK-deficient patients, no negative correlation with hepcidin was found. This result indicates the existence of another as-yet unidentified erythroid regulator of hepcidin synthesis in PK deficiency.

• MeSH
• dítě MeSH
• dospělí MeSH
• erytropoéza MeSH
• ferritin krev   MeSH
• hemolytická nesférocytická kongenitální anemie krev   genetika   MeSH
• hepcidiny biosyntéza   krev   MeSH
• kojenec MeSH
• krevní transfuze MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• molekulární sekvence - údaje MeSH
• mutace * MeSH
• mutační analýza DNA MeSH
• novorozenec MeSH
• potransfuzní reakce MeSH
• předškolní dítě MeSH
• přetížení železem genetika   MeSH
• pyruvátkinasa krev   nedostatek   genetika   MeSH
• sekvence aminokyselin MeSH
• sekvenční analýza DNA MeSH
• vrozené poruchy metabolismu pyruvátu krev   genetika   MeSH
• železo krev   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• exom * MeSH
• fenotyp * MeSH
• geny vázané na chromozom X * MeSH
• lidé MeSH
• mozek metabolismus   MeSH
• mutace * MeSH
• přetížení železem genetika   MeSH
• transportní proteiny genetika   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• komentáře MeSH

The aim of the study was to identify the prevalence of HFE gene mutations in Czech patients with chronic liver diseases and the influence of the mutations on iron status. The presence of HFE gene mutations (C282Y, H63D, and S65C) analyzed by the PCR-RFLP method, presence of cirrhosis, and serum iron indices were compared among 454 patients with different chronic liver diseases (51 with chronic hepatitis B, 122 with chronic hepatitis C, 218 with alcoholic liver disease, and 63 patients with hemochromatosis). Chronic liver diseases patients other than hemochromatics did not have an increased frequency of HFE gene mutations compared to controls. Although 33.3% of patients with hepatitis B, 43% of patients with hepatitis C, and 73.2% of patients with alcoholic liver disease had elevated transferrin saturation or serum ferritin levels, the presence of HFE gene mutations was not significantly associated with iron overload in these patients. Additionally, patients with cirrhosis did not have frequencies of HFE mutations different from those without cirrhosis. This study emphasizes the importance, not only of C282Y, but also of the H63D homozygous genetic constellation in Czech hemochromatosis patients. Our findings show that increased iron indices are common in chronic liver diseases but {\it HFE} mutations do not play an important role in the pathogenesis of chronic hepatitis B, chronic hepatitis C, and alcoholic liver disease.

• MeSH
• alkoholické nemoci jater genetika   MeSH
• chronická hepatitida B genetika   MeSH
• chronická hepatitida C genetika   MeSH
• chronická nemoc MeSH
• dospělí MeSH
• ferritin krev   MeSH
• frekvence genu MeSH
• hemochromatóza genetika   MeSH
• histokompatibilita - antigeny třídy I genetika   MeSH
• homozygot MeSH
• jaterní cirhóza genetika   MeSH
• lidé středního věku MeSH
• lidé MeSH
• membránové proteiny genetika   MeSH
• mladý dospělý MeSH
• mutace MeSH
• nemoci jater genetika   MeSH
• polymerázová řetězová reakce MeSH
• polymorfismus délky restrikčních fragmentů MeSH
• přetížení železem genetika   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• transferin metabolismus   MeSH
• železo krev   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

INTRODUCTION: Hemojuvelin (Hjv) is a key component of the signaling cascade that regulates liver hepcidin (Hamp) expression. The purpose of this study was to determine Hjv protein levels in mice and rats subjected to iron overload and iron deficiency. METHODS: C57BL/6 mice were injected with iron (200 mg/kg); iron deficiency was induced by feeding of an iron-deficient diet, or by repeated phlebotomies. Erythropoietin (EPO)-treated mice were administered recombinant EPO at 50 U/mouse. Wistar rats were injected with iron (1200 mg/kg), or fed an iron-deficient diet. Hjv protein was determined by immunoblotting, liver samples from Hjv-/- mice were used as negative controls. Mouse plasma Hjv content was determined by a commercial ELISA kit. RESULTS: Liver crude membrane fraction from both mice and rats displayed a major Hjv-specific band at 35 kDa, and a weaker band of 20 kDa. In mice, the intensity of these bands was not changed following iron injection, repeated bleeding, low iron diet or EPO administration. No change in liver crude membrane Hjv protein was observed in iron-treated or iron-deficient rats. ELISA assay for mouse plasma Hjv did not show significant difference between Hjv+/+ and Hjv-/- mice. Liver Hamp mRNA, Bmp6 mRNA and Id1 mRNA displayed the expected response to iron overload and iron deficiency. EPO treatment decreased Id1 mRNA, suggesting possible participation of the bone morphogenetic protein pathway in EPO-mediated downregulation of Hamp mRNA. DISCUSSION: Since no differences between Hjv protein levels were found following various experimental manipulations of body iron status, the results indicate that, in vivo, substantial changes in Hamp mRNA can occur without noticeable changes of membrane hemojuvelin content. Therefore, modulation of hemojuvelin protein content apparently does not represent the limiting step in the control of Hamp gene expression.

• MeSH
• deficit železa MeSH
• dietní železo metabolismus   MeSH
• erythropoetin farmakologie   MeSH
• játra účinky léků   metabolismus   MeSH
• kostní morfogenetické proteiny genetika   metabolismus   MeSH
• krysa rodu rattus MeSH
• membránové proteiny genetika   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• potkani Wistar MeSH
• přetížení železem genetika   metabolismus   MeSH
• signální transdukce účinky léků   genetika   MeSH
• železo metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: Iron overload and hepatitis C virus (HCV) infection are independent factors which are thought to play a role in the pathogenesis of porphyria cutanea tarda (PCT). OBJECTIVES: To determine the prevalence of the HFE gene mutations p.Cys282Tyr (C282Y), p.His63Asp (H63D) and p.Ser65Cys (S65C), the p.Tyr250X (Y250X) mutation of the TFR2 gene, and HCV infection in patients with PCT in the Czech population, and to make comparison of the iron status among the respective genotypes. METHODS: Iron metabolism indices, results of mutational analysis and serological markers of HCV infection were examined in 63 patients with PCT. RESULTS: The HFE gene mutations were detected in 70% of patients with PCT compared with 35% in the control group (P < 0.001). Mean serum ferritin levels were increased in all genotypes, the highest being in homozygotes for the p.Cys282Tyr mutation. HCV infection was detected in only 8% of patients with PCT. CONCLUSIONS: There was a very high prevalence of the p.Cys282Tyr and p.His63Asp mutations observed in patients with PCT accompanied by mild degrees of iron overload, which was genotype dependent.

• MeSH
• biologické markery krev   MeSH
• chronická hepatitida C komplikace   MeSH
• dospělí MeSH
• ferritin analýza   MeSH
• financování organizované MeSH
• genetická predispozice k nemoci MeSH
• genotyp MeSH
• Hepacivirus MeSH
• histokompatibilita - antigeny třídy I MeSH
• homozygot MeSH
• lidé středního věku MeSH
• lidé MeSH
• membránové proteiny genetika   MeSH
• mutace MeSH
• mutační analýza DNA MeSH
• porphyria cutanea tarda genetika   virologie   MeSH
• přetížení železem genetika   komplikace   MeSH
• prevalence MeSH
• rozdělení chí kvadrát MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Geografické názvy
• Česká republika MeSH

Hereditary hemochromatosis type I is an autosomal-recessive iron overload disease associated with a mutation in HFE gene. The most common mutation, C282Y, disrupts the disulfide bond necessary for the association of HFE with beta-2-microglobulin and abrogates cell surface HFE expression. HFE-deficient mice develop iron overload indicating a central role of the protein in the pathogenesis of hereditary hemochromatosis type I. However, despite significant effort, the role of the HFE protein in iron metabolism is still unknown. To shed a light on the molecular mechanism of HFE-related hemochromatosis we studied protein expression changes elicited by HFE-deficiency in the liver which is the organ critical for the regulation of iron metabolism. We undertook a proteomic study comparing protein expression in the liver of HFE deficient mice with control animals. We compared HFE-deficient animals with control animals with identical iron levels obtained by dietary treatment to identify changes specific to HFE deficiency rather than iron loading. We found 11 proteins that were differentially expressed in the HFE-deficient liver using two-dimensional electrophoresis and mass spectrometry identification. Of particular interest were urinary proteins 1, 2 and 6, glutathione-S-transferase P1, selenium binding protein 2, sarcosine dehydrogenase and thioredoxin-like protein 2. Our data suggest possible involvement of lipocalins, TNF-alpha signaling and PPAR alpha regulatory pathway in the pathogenesis of hereditary hemochromatosis and suggest future targeted research addressing the roles of the identified candidate genes in the molecular mechanism of hereditary hemochromatosis.

• MeSH
• 2D gelová elektroforéza MeSH
• exprese genu MeSH
• financování organizované MeSH
• hemochromatóza genetika   metabolismus   patologie   MeSH
• histokompatibilita - antigeny třídy I fyziologie   genetika   MeSH
• játra metabolismus   MeSH
• membránové proteiny fyziologie   genetika   nedostatek   MeSH
• messenger RNA genetika   metabolismus   MeSH
• molekulární sekvence - údaje MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• polymerázová řetězová reakce MeSH
• přetížení železem genetika   metabolismus   patologie   MeSH
• proteom genetika   metabolismus   MeSH
• proteomika metody   MeSH
• sekvence aminokyselin MeSH
• spektrofotometrie atomová MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• železo metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH

Divalent metal transporter 1 (DMT1) is a transmembrane protein crucial for duodenal iron absorption and erythroid iron transport. DMT1 function has been elucidated largely in studies of the mk mouse and the Belgrade rat, which have an identical single nucleotide mutation of this gene that affects protein processing, stability, and function. These animals exhibit hypochromic microcytic anemia due to impaired intestinal iron absorption, and defective iron utilization in red cell precursors. We report here the first human mutation of DMT1 identified in a female with severe hypochromic microcytic anemia and iron overload. This homozygous mutation in the ultimate nucleotide of exon 12 codes for a conservative E399D amino acid substitution; however, its pre-dominant effect is preferential skipping of exon 12 during processing of pre-messenger RNA (mRNA). The lack of full-length mRNA would predict deficient iron absorption in the intestine and deficient iron utilization in erythroid precursors; however, unlike the animal models of DMT1 mutation, the patient is iron overloaded. This does not appear to be due to up-regulation of total DMT1 mRNA. DMT1 protein is easily detectable by immunoblotting in the patient's duodenum, but it is unclear whether the protein is properly processed or targeted.

• MeSH
• biopsie MeSH
• exony genetika   MeSH
• hepatocyty patologie   MeSH
• hypochromní anemie genetika   komplikace   patologie   MeSH
• játra patologie   MeSH
• jednonukleotidový polymorfismus genetika   MeSH
• krysa rodu rattus MeSH
• Kupfferovy buňky patologie   MeSH
• lidé MeSH
• messenger RNA genetika   MeSH
• modely nemocí na zvířatech MeSH
• mutace MeSH
• myši MeSH
• přetížení železem genetika   komplikace   patologie   MeSH
• transkripční faktory MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH