Hamp deletion disrupts hemoglobin synthesis by ferropotosis during zebrafish embryogenesis
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ABSTRACT:
ORGANISM(S): Danio rerio
PROVIDER: GSE260987 | GEO | 2026/03/30
REPOSITORIES: GEO
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Project description:Iron-related disorders are among the most prevalent diseases worldwide. Systemic iron homeostasis requires hepcidin (Hamp), a hepatic-derived hormone that controls iron mobilization through its molecular target, ferroportin (FPN), the only known mammalian iron exporter. Here, we took a transcriptomic approach to to compare the duodenal transcriptome during systemic iron demand to that of hepcidin-deficiency iron overload. Hampfl/fl (control) and AlbCreERT2;Hampfl/fl mice were placed on iron-replete and low-iron diets and were sacrificed two weeks following tamoxifen treatment. Duodenum RNA expression was compared across genotypes and across iron-replete and low iron diets.
2018-12-12 | E-MTAB-7329 | biostudies-arrayexpress
Project description:Inflammation influences iron balance in the whole organism. A common clinical manifestation of these changes is the anemia of chronic disease (ACD; also called anemia of inflammation). Inflammation reduces duodenal iron absorption and increases macrophage iron storage, resulting in low serum iron concentrations (hyposideremia). Despite the protection hyposideremia provides against proliferating microorganisms, this iron withholding reduces the iron available to developing red blood cells and eventually contributes to the development of anemia. Hepcidin antimicrobial peptide (Hamp) is a hepatic defensin-like peptide hormone that inhibits duodenal iron absorption and macrophage iron release. Hamp has antimicrobial activity and is part of the type II acute phase response. It is also thought to play a critical regulatory role in the sequestration of iron in the context of ACD. We report that mice with deficiencies in the hemochromatosis gene product, Hfe, mount a general inflammatory response, but lack appropriate Hamp expression and fail to develop hyposideremia. These data suggest a previously unidentified role for Hfe in innate immunity and ACD.
2004-03-15 | E-MEXP-95 | biostudies-arrayexpress
Project description:Homeostatic adaptation to systemic iron overload involves transcriptional induction of bone morphogenetic protein 6 (BMP6) in liver sinusoidal endothelial cells (LSECs). BMP6 is then secreted to activate signaling to the iron hormone hepcidin (Hamp) in neighboring hepatocytes. To explore the mechanism for iron sensing by LSECs, we generated TfrcTek-Cre mice with endothelial cell-specific ablation of transferrin receptor 1 (Tfr1). We also used wild type mice to characterize LSEC-specific molecular responses to iron by single cell transcriptomics. TfrcTek-Cre animals tend to have increased liver iron content compared to Tfrcfl/fl controls but do not exhibit blunted Bmp6 or Hamp mRNA expression. They respond to dietary iron challenges with Bmp6 and Hamp induction, yet sometimes to levels slightly lower relative to liver iron load. We noted that liver Bmp6 and Hamp mRNA levels significantly correlated with serum non-transferrin bound iron (NTBI) that emerged following dietary iron loading in both TfrcTek-Cre and Tfrcfl/fl mice. High dietary iron triggered more profound alterations in the LSEC transcriptome of Tfrcfl/fl mice compared to holo-transferrin injection. These culminated in robust induction of Bmp6 and other nuclear factor erythroid 2-related factor 2 (Nrf2) target genes, as well as Myc target genes involved in ribosomal biogenesis and protein synthesis. Taken together, our data suggest that during systemic iron overload, LSECs internalize NTBI, which promotes oxidative stress and thereby transcriptionally induces Bmp6 via Nrf2. The contribution of Tfr1 and transferrin-bound iron to Bmp6 induction is minimal.
2022-12-21 | GSE215324 | GEO
Project description:Hepcidin, a peptide hormone that decreases intestinal iron absorption and macrophage iron release, is a potential drug target for patients with iron overload syndromes because its levels are inappropriately low in these individuals. Endogenous stimulants of Hepcidin transcription include bone morphogenic protein 6 (BMP) and interleukin-6 (IL-6) via effects on Smad4 or Stat3, respectively. We conducted a small-scale chemical screen in zebrafish embryos to identify small molecules that modulate hepcidin expression. We found that treatment with the isoflavone genistein from 28−52 hours post-fertilization in zebrafish embryos enhanced Hepcidin transcript levels as assessed by whole mount in situ hybridization and quantitative realtime RT-PCR. Genistein’s stimulatory effect was conserved in human hepatocytes: genistein treatment of HepG2 cells increased both Hepcidin transcript levels and Hepcidin promoter activity. We found that genistein’s effect on Hepcidin expression did not depend on estrogen receptor signaling or increased cellular iron uptake, but was impaired by mutation of either the BMP response elements or the Stat3 binding site in the Hepcidin promoter. RNA-sequencing of transcripts from genistein-treated hepatocytes indicated that genistein upregulated 68% of the transcripts that were upregulated by BMP6, however genistein raised the levels of several transcripts involved in Stat3 signaling that were not upregulated by BMP6. Chromatin-immunoprecipitation and ELISA experiments revealed that genistein enhanced Stat3 binding to the Hepcidin promoter and increased phosphorylation of Stat3 in HepG2 cells. CONCLUSION: Genistein is the first small molecule experimental drug that stimulates Hepcidin expression in vivo and in vitro. These experiments demonstrate the feasibility of identifying and characterizing small molecules that increase Hepcidin expression. Genistein and other candidate molecules may subsequently be developed into new therapies for iron overload syndromes. RNA-seq of HepG2 cells treated with DMSO 1%, BMP6 50 ng/ml, or genistein 10 micromolar. The numbers of biological replicates were 3, 2, and 3.
2015-08-13 | E-GEOD-40069 | biostudies-arrayexpress
Project description:Hepcidin, a peptide hormone that decreases intestinal iron absorption and macrophage iron release, is a potential drug target for patients with iron overload syndromes because its levels are inappropriately low in these individuals. Endogenous stimulants of Hepcidin transcription include bone morphogenic protein 6 (BMP) and interleukin-6 (IL-6) via effects on Smad4 or Stat3, respectively. We conducted a small-scale chemical screen in zebrafish embryos to identify small molecules that modulate hepcidin expression. We found that treatment with the isoflavone genistein from 28−52 hours post-fertilization in zebrafish embryos enhanced Hepcidin transcript levels as assessed by whole mount in situ hybridization and quantitative realtime RT-PCR. Genistein’s stimulatory effect was conserved in human hepatocytes: genistein treatment of HepG2 cells increased both Hepcidin transcript levels and Hepcidin promoter activity. We found that genistein’s effect on Hepcidin expression did not depend on estrogen receptor signaling or increased cellular iron uptake, but was impaired by mutation of either the BMP response elements or the Stat3 binding site in the Hepcidin promoter. RNA-sequencing of transcripts from genistein-treated hepatocytes indicated that genistein upregulated 68% of the transcripts that were upregulated by BMP6, however genistein raised the levels of several transcripts involved in Stat3 signaling that were not upregulated by BMP6. Chromatin-immunoprecipitation and ELISA experiments revealed that genistein enhanced Stat3 binding to the Hepcidin promoter and increased phosphorylation of Stat3 in HepG2 cells. CONCLUSION: Genistein is the first small molecule experimental drug that stimulates Hepcidin expression in vivo and in vitro. These experiments demonstrate the feasibility of identifying and characterizing small molecules that increase Hepcidin expression. Genistein and other candidate molecules may subsequently be developed into new therapies for iron overload syndromes.
2015-08-13 | GSE40069 | GEO
Project description:Liver iron overload can induce hepatic expression of hepcidin and regulates iron metabolism. However, the mechanism of iron regulating iron metabolism remains known. Intracellular labile iron represents the nonferritin-bound, redox-active iron which is transitory and serves as a crossroad of cell iron metabolism. The role of intracellular labile iron played in iron metabolism has largely been elucidated. Here we show that intracellular labile iron of hepatocytes has dual function in iron metabolism. It can induce hepatocytes expressing hepcidin via ER stress induced transcription factors on the one hand, on the other hand stimulate BMP2 and BMP6 expression of liver sinusoidal endothelial cells (LSECs) though TNFα secreted by hepatocytes to further regulate iron metabolism. Blockade of TNFα could dysregulate the iron metabolism during iron overload. Our findings reveal the important role of intracellular labile iron in iron metabolism and represent a novel way to modulate iron metabolism during iron overload.
2023-05-03 | GSE186655 | GEO
Project description:Hemolysis of senescent erythrocytes occurs in the spleen, resulting in hemoglobin (Hb) release. Several diseases are associated with an increased risk of erythrocyte rupture. Iron recycling from Hb and Hb detoxification have been attributed to the sequestration of Hb-haptoglobin complexes by macrophages, however, other routes of Hb clearance might exist. We identified liver sinusoidal endothelial cells (LSECs) as the major cell type that sequesters Hb. Hb uptake involves macropinocytosis and is independent of haptoglobin and the Hb-haptoglobin receptor CD163. LSECs expressed heme oxygenase 1 and hepcidin-controlled ferroportin and were the most efficient cellular scavengers of Hb at doses below the haptoglobin binding capacity. Erythrocyte transfusion assays demonstrated that while splenic red pulp macrophages are efficient in erytrophagocytosis, liver Kupffer cells and LSECs are primarily involved in the clearance of erythrocyte ghosts and Hb, respectively. Using time-course injections of high doses of Hb in mice, we detected transient hepatic iron retention, early induction of Hmox1 specifically in LSECs, and elevation of ferroportin levels. This was associated with transcriptional activation of LSEC Bmp6, followed by hepcidin-mediated transient hypoferremia. Injection of Hb and iron-citrate elicited distinct transcriptional signatures in LSECs and the early Bmp6 induction was phenocopied by erythrocyte lysis upon phenylhydrazine. Collectively, we propose that LSECs provide a key mechanism for Hb clearance, a function that establishes the spleen-liver axis for physiological iron recycling from Hb and contributes to heme detoxification during hemolysis, coupled with the induction of the BMP6-hepcidin axis that restores homeostasis.
2025-08-01 | GSE240270 | GEO
Project description:High levels of hepcidin, the main regulator of systemic iron metabolism leads to various diseases. Targeting hepcidin and lowering its concentration is a possible form of intervention in order to treat these diseases. High turnover rate of hepcidin is a major drawback of therapies directly targeting this peptide. We developed two monoclonal antibodies (mAbs) ABT-207 and h5F9-AM8 which inhibit hemojuvelin also known as repulsive guidance molecule c (RGMc) and downregulate hepcidin. After a single application of these antibodies hepcidin expression in liver and its concentration in serum were reduced. Serum iron increased for several weeks. The RGMc antibodies show a pronounced dose response relationship in rats with h5F9-AM8 having an IC50 (UIBC) of ~80 fold higher than ABT-207. When hepcidin levels were downregulated iron deposition in the liver was visible histologically one week post application. The anitbody-mediated iron deposition was not associated with any toxicologically relevant effect at the doses and timepoints evaluate. Iron depositions seen after 14 weekly treatments with ABT-207 were partially reversible in rats and in cynomolgus monkeys. Due to their long-lasting effects and excellent safety profile, both RGMc-blocking antibodies ABT-207 and h5F9-AM8 are favorable clinical candidates for diseases characterized by high serum hepcidin levels like anemia of chronic disease.
2014-11-14 | GSE63200 | GEO
Project description:Tmprss6 is the master inhibitor of hepcidin and its inactivation causes iron refractory iron deficiency anemia both in human and in mice. Mice with iron deficiency anemia (IDA)-low hepcidin show a pro-inflammatory response that is blunted in iron deficienct-high hepcidin Tmprss6 null mice. We investigated the transcriptional response associated with chronic hepcidin overexpression by comparing whole genome transcription profiling of the liver of Tmprss6 KO mice and IDA animals, irrespective of iron deficiency.
2013-10-09 | GSE46287 | GEO
Project description:Tmprss6 is the master inhibitor of hepcidin and its inactivation causes iron refractory iron deficiency anemia both in human and in mice. Mice with iron deficiency anemia (IDA)-low hepcidin show a pro-inflammatory response that is blunted in iron deficienct-high hepcidin Tmprss6 null mice. We investigated the transcriptional response associated with chronic hepcidin overexpression by comparing whole genome transcription profiling of the liver of Tmprss6 KO mice and IDA animals, irrespective of iron deficiency. Total liver RNA obtained from Tmprss6 KO mice were compared to wild type (iron deficient) animals, under basal conditions and after LPS challenge
2013-10-09 | E-GEOD-46287 | biostudies-arrayexpress