A mutation in the TMPRSS6 gene, encoding a transmembrane serine protease that suppresses hepcidin production, in familial iron deficiency anemia refractory to oral iron.

Background Hepcidin plays a key role in body iron metabolism by preventing the release of iron from macrophages and intestinal cells. Defective hepcidin synthesis causes iron loading, while overproduction results in defective reticuloendothelial iron release and iron absorption. Design and Methods We studied a Sardinian family in which microcytic anemia due to defective iron absorption and utilization is inherited as a recessive character. Five members showed iron deficiency anemia that was not responsive to oral iron and only partially responsive to parenteral iron administration. To investigate the involvement of known genes implicated in iron metabolism we carried out linkage analysis with microsatellite markers mapping close to these genes. Afterwards, a genome-wide search was performed. Results No linkage was found between the phenotype of the patients and several known human genes involved in iron metabolism ( DMT1, TF, TFRC, ZIRTL, HAMP, HJV ). Genome-wide scanning by microsatellites and single nucleotide polymorphisms showed a multipoint LOD score of 5.6 on chromosome 22q12.3–13.1, where the matriptase-2 (also known as transmembrane protease, serine 6 or TMPRSS6 ) gene is located. Its murine counterpart ( Tmprss6 ) has recently been found to be an essential component of a pathway that detects iron deficiency and suppresses hepcidin production. Sequencing analysis of TMPRSS6 revealed a homozygous causal mutation, predicting a splicing error and a truncated TMPRSS6 protein in affected members. Homozygous subjects had inappropriately elevated levels of serum and urinary hepcidin. Conclusions The findings of this study suggest that the observed TMPRSS6 mutation leads to overproduction of hepcidin and, in turn, to defective iron absorption and utilization. More generally, they confirm in humans the inhibitory effect of matriptase-2 on hepcidin synthesis already demonstrated in mice

CIJEPLJENJE HIBRIDNOG LUBINA: RAST, IMUNOLOŠKA REAKCIJA I EKSPRESIJA GENA

Hybrid striped bass (42.6+4.9 g wet wt; 139.3+6.1 mm length), were randomly stocked into one of 6 tanks (n=6 tank-1) of a custom designed, recirculating life support system (RLSS). Water quality was as follows: DO2 (6.50.6 mg l-1), pH (7.70.5), TAN (0.06-1.31 mg l-1), nitrite (0.06-0.60 mg l-1) and nitrate (2.0-32.1 mg l-1), salinity 5 ppt, temperature 28±1 oC. A 12:12 photophase:scotophase was used, with a 30 min. dusk-dawn dimming of lights. Fish were fed at 4% body wt d-1 as two separate feedings (08.00 and 16.00 h). Dietary crude protein and lipid levels were 40% and 10% respectively. Tanks were randomly paired and fish either left untreated, vaccinated, or sham injected. The vaccine employed was an experimental formalin killed Streptococcus iniae oil-in-water adjuvanted bacterin. Fish were weighed and measured bimonthly for 8 wk with group weights being employed to adjust feeding rates. At trial termination, all animals were weighed and measured, and their condition factor (CF) and feed conversion ratios (FCR) calculated. Visceral somatic (VSI) and hepatosomatic (HSI) indices and intraperitoneal fat (IPF) and muscle ratios (MR) were also assessed. Blood was taken from anaesthetized fish and hematocrit recorded. Blood was allowed to clot overnight at 5 oC after which serum protein levels were recorded and lysozyme activity measured. Livers were prepared for microarray evaluation using standard techniques using a Danio rerio genechip to assess global changes in gene expression. No differences were observed with respect to final weights, lengths, CF, FCR, or HSI although differences (P 0.05). Time-course of changes in serum lysozyme activity described an initial reduction in lysozyme activity followed by a rebounding in activity which peaked 25 days post-treatments. Evaluation of lysozyme activity among time-points revealed differences (P < 0.05) between 11 and 25 days post-vaccination. Examination of the hepatic microarray datasets revealed only four immune-discrete genes that were impacted 53-days following vaccination when compared against control fish. These included the up-regulated TCIRG1, or T-cell immune regulator 1 (P < 0.0467) and IL20RA, or interleukin 20 receptor alpha (P < 0.0433), and down-regulated cytokine inducible kinase, plk3 (P < 0.01) and mouse immune responsive protein, IRG1 (P < 0.01).Hibridni lubini (42,6+4,9 g mokre težine; 139,3+6,1 mm dužine) su nasumce stavljeni u jedan od 6 spremnika (n=6 spremnik-1) s recirkulirajućim sustavom za održavanje života (RLSS) izrađenim po mjeri. Kvaliteta vode je bila sljedeća: DO2 (6,50,6 mg l-1), pH (7,70,5), TAN (0,06-1,31 mg l-1), nitrit (0,06-0,60 mg l-1) i nitrat (2,0-32,1 mg l-1), salinitet 5 ppt, temperatura 28±1oC. 12:12 fotofaza:skotofaza je korištena s 30-minutnim zatamnjivanjem svjetala u zoru i sumrak. Ribe su hranjene s udjelom od 4% tjelesne težine d-1 u dva odvojena hranjenja (u 08.00 i 16.00 sati). Razina hranidbenog sirovog proteina i lipida je bila 40%, odnosno 10%. Spremnici su bili nasumce spajani te je riba bila netretirana, cijepljena ili cijepljena placebo injekcijom. Cjepivo koje je korišteno je eksperimentalni bakterin s adjuvansom „ulje u vodi“ vrste Streptococcus iniae usmrćene formalinom. Riba je vagana i mjerena dvaput mjesečno tijekom 8 tjedana, a težinske grupe su se koristile za prilagođavanje količine hrane. Po završetku testiranja, sve ribe su vagane i mjerene te je izračunat njihov faktor kondicije (CF) i odnos promjene hranjenja (FCR). Visceralno somatski (VSI) i hepatosomatski (HSI) indeksi te intraperitonealna masnoća (IPF) i mišićni odnos (MR) su također procijenjeni. Anesteziranoj ribi se vadila krv i zabilježen je hematokrit. Dopušteno je da se tijekom noći krv zgruša na 5oC nakon čega je zabilježena razina serumskih proteina i izmjerena aktivnost lizozima. Jetra su pripremljena za procjenu mikroniza koristeći se standardnim tehnikama pomoću genskog čipa Danio rerio kako bi procijenili globalne promjene u ekspresiji gena. Nije primijećena nikakva razlika u konačnoj težini, dužini, CF-u, FCR-u ili HSI-u iako su razlike (P 0,05). Promjene u aktivnosti serumskog lizozima tijekom vremena ukazuju na početno smanjenje aktivnosti lizozima, nakon čega slijedi preokret u aktivnosti koji doseže svoj vrhunac 25 dana nakon tretmana. Procjena aktivnosti lizozima u vremenskim razmacima otkrila je razlike (P < 0,05) od 11 do 25 dana nakon cijepljenja. Ispitivanjem zbira podataka hepatičkog mikroniza otkrivena su samo četiri imuno-diskretna gena na koje je cjepivo djelovalo nakon 53 dana, u usporedbi s kontroliranom skupinom. Oni uključuju \u27up-regulirani\u27 TCIRG1, ili imunološki regulator T-cell 1 (P < 0,0467) i IL20RA, ili interleukin 20 receptor alfa (P < 0,0433), te \u27down-reguliranu\u27 kinazu koja inducira citokin, plk3 (P < 0,01) i protein s imunološkom reakcijom kod miševa, IRG1 (P < 0,01)

Highly Elevated Serum Hepcidin in Patients with Acute Myeloid Leukemia prior to and after Allogeneic Hematopoietic Cell Transplantation: Does This Protect from Excessive Parenchymal Iron Loading?

Hepcidin is upregulated by inflammation and iron. Inherited (HFE genotype) and treatment-related factors (blood units (BU), Iron overload) affecting hepcidin (measured by C-ELISA) were studied in 42 consecutive patients with AML prior to and after allogeneic hematopoietic cell transplantation (HCT). Results. Elevated serum ferritin pre- and post-HCT was present in all patients. Median hepcidin pre- and post-HCT of 358 and 398 ng/mL, respectively, were elevated compared to controls (median 52 ng/mL) (P<.0001). Liver and renal function, prior chemotherapies, and conditioning had no impact on hepcidin. Despite higher total BU after HCT compared to pretransplantation (P<.0005), pre- and posttransplant ferritin and hepcidin were similar. BU influenced ferritin (P=.001) and hepcidin (P=.001). No correlation of pre- or posttransplant hepcidin with pretransplant ferritin was found. HFE genotype did not influence hepcidin. Conclusions. Hepcidin is elevated in AML patients pre- and post-HCT due to transfusional iron-loading suggesting that hepcidin synthesis remains intact despite chemotherapy and HCT

Iron Homeostasis during Cystic Fibrosis Pulmonary Exacerbation

BACKGROUND: Hypoferremia is a marker of disease severity in cystic fibrosis (CF). The effect of systemic antibiotics on iron homeostasis during CF pulmonary exacerbation (CFPE) is unknown. Our central hypotheses were that, by the completion of treatment, serum iron would increase, serum concentrations of interleukin-6 (IL-6) and hepcidin-25, two mediators of hypoferremia, would decrease, and sputum iron would decrease. METHODS: Blood and sputum samples were collected from 12 subjects with moderate-to-severe CF (median percentage-predicted forced expiratory volume in 1 second (FEV(1) %) = 29%; median weight = 56 kg) within 24 hours of starting and completing a course of systemic antibiotics. RESULTS: After treatment, subjects showed median FEV(1) % and body weight improvements of 4.5% and 2.0 kg, respectively (p \u3c 0.05). Median serum iron rose by 2.4 μmol/L (p \u3c 0.05), but 75% of patients remained hypoferremic. Median serum IL-6 and hepcidin-25 levels fell by 12.1 pg/mL and 37.5 ng/mL, respectively (p \u3c 0.05). Median serum erythropoietin (EPO) and hemoglobin levels were unaffected by treatment. We observed a trend toward lower sputum iron content after treatment. CONCLUSIONS: Hypoferremia is a salient characteristic of CFPE that improves with waning inflammation. Despite antibiotic treatment, many patients remain hypoferremic and anemic because of ineffective erythropoiesis

Urine hepcidin has additive value in ruling out cardiopulmonary bypass-associated acute kidney injury: an observational cohort study

This study was supported by grants from the German Heart Foundation (Deutsche Stiftung für Herzforschung) and from the Else Kröner-Fresenius-Stiftung, Germany

Increased hepcidin in transferrin-treated thalassemic mice correlates with increased liver BMP2 expression and decreased hepatocyte ERK activation

Iron overload results in significant morbidity and mortality in \u3b2-thalassemic patients. Insufficient hepcidin is implicated in parenchymal iron overload in \u3b2-thalassemia and approaches to increase hepcidin have therapeutic potential. We have previously shown that exogenous apo-transferrin markedly ameliorates ineffective erythropoiesis and increases hepcidin expression in Hbbth1/th1 (thalassemic) mice. We utilize in vivo and in vitro systems to investigate effects of exogenous apo-transferrin on Smad and ERK1/2 signaling, pathways that participate in hepcidin regulation. Our results demonstrate that apo-transferrin increases hepcidin expression in vivo despite decreased circulating and parenchymal iron concentrations and unchanged liver Bmp6 mRNA expression in thalassemic mice. Hepatocytes from apo-transferrin treated mice demonstrate decreased ERK1/2 pathway and increased serum BMP2 concentration and hepatocyte BMP2 expression. Furthermore, hepatocyte ERK1/2 phosphorylation is enhanced by neutralizing anti-BMP2/4 antibodies and suppressed by BMP2 in vitro, resulting in converse effects on hepcidin expression, and hepatocytes treated with MEK/ERK1/2 inhibitor U0126 in combination with BMP2 exhibit a more than additive increase in hepcidin expression. Lastly, bone marrow erythroferrone expression is normalized in apo-transferrin treated thalassemic mice but increased in apo-transferrin injected wild type mice. These findings suggest that increased hepcidin expression after exogenous apo-transferrin is in part independent of erythroferrone and support a model in which apo-transferrin treatment in thalassemic mice increases BMP2 expression in the liver and other organs, decreases hepatocellular ERK1/2 activation, and increases nuclear Smad to increase hepcidin expression

Phylogenetic relationships of dasyuromorphian marsupials revisited

We reassessed the phylogenetic relationships of dasyuromorphians using a large molecular database comprising previously published and new sequences for both nuclear (nDNA) and mitochondrial (mtDNA) genes from the numbat (Myrmecobius fasciatus), most living species of Dasyuridae, and the recently extinct marsupial wolf, Thylacinus cynocephalus. Our molecular tree suggests that Thylacinidae is sister to Myrmecobiidae + Dasyuridae. We show robust support for the dasyurid intrafamilial classification proposed by Krajewski & Westerman as well as for placement of most dasyurid genera, which suggests substantial homoplasy amongst craniodental characters presently used to generate morphology-based taxonomies. Molecular dating with relaxed molecular clocks suggests that dasyuromorphian cladogenesis began in the Eocene, and that all three dasyuromorphian families originated prior to the end of this epoch. Radiation within Thylacinidae and Dasyuridae had occurred by the middle to late Oligocene, consistent with recognition of primitive thylacinids (e.g. Badjcinus turnbulli) in the later Oligocene and of putative dasyurids (e.g. Barinya wangala) by the early Miocene. We propose that all four extant dasyurid tribes were in existence by the early Miocene and that most modern dasyurid genera/species were established before the later Miocene. This is in marked contrast to the popularly accepted advocation of their origins in the latest Miocene–early Pliocene

Highly Elevated Serum Hepcidin in Patients with Acute Myeloid Leukemia prior to and after Allogeneic Hematopoietic Cell Transplantation: Does This Protect from Excessive Parenchymal Iron Loading?

Hepcidin is upregulated by inflammation and iron. Inherited (HFE genotype) and treatment-related factors (blood units (BU), Iron overload) affecting hepcidin (measured by C-ELISA) were studied in 42 consecutive patients with AML prior to and after allogeneic hematopoietic cell transplantation (HCT). Results. Elevated serum ferritin pre-and post-HCT was present in all patients. Median hepcidin pre-and post-HCT of 358 and 398 ng/mL, respectively, were elevated compared to controls (median 52 ng/mL) (P &lt; .0001). Liver and renal function, prior chemotherapies, and conditioning had no impact on hepcidin. Despite higher total BU after HCT compared to pretransplantation (P &lt; .0005), pre-and posttransplant ferritin and hepcidin were similar. BU influenced ferritin (P = .001) and hepcidin (P = .001). No correlation of pre-or posttransplant hepcidin with pretransplant ferritin was found. HFE genotype did not influence hepcidin. Conclusions. Hepcidin is elevated in AML patients pre-and post-HCT due to transfusional iron-loading suggesting that hepcidin synthesis remains intact despite chemotherapy and HCT