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  1. Article ; Online: CREB-H is a stress-regulator of hepcidin gene expression during early postnatal development.

    Vecchi, Chiara / Montosi, Giuliana / Garuti, Cinzia / Canali, Susanna / Sabelli, Manuela / Bergamini, Elisa / Ricci, Andrea / Buzzetti, Elena / Corradini, Elena / Pietrangelo, Antonello

    Journal of molecular medicine (Berlin, Germany)

    2023  Volume 101, Issue 9, Page(s) 1113–1124

    Abstract: Hepcidin, the hepatic iron hormone, is the central regulator of iron homeostasis. Cyclic AMP-Responsive Element-Binding protein 3-like 3 (CREB3L3/CREB-H) is a liver homeostatic regulator of essential nutrients (i.e. glucose and lipids) and has been ... ...

    Abstract Hepcidin, the hepatic iron hormone, is the central regulator of iron homeostasis. Cyclic AMP-Responsive Element-Binding protein 3-like 3 (CREB3L3/CREB-H) is a liver homeostatic regulator of essential nutrients (i.e. glucose and lipids) and has been previously involved in hepcidin response to pathologic stress signals. Here, we asked whether CREB-H has also a physiologic role in iron homeostasis through hepcidin. To this end, we analyzed hepcidin gene expression and regulation in the liver of wild type and Creb3l3 knockout mice during early postnatal development, as a model of "physiologic" stressful condition. The effect of iron challenge in vivo and BMP6 stimulation in vitro have been also addressed. In addition, we investigated the BMP signaling pathway and hepcidin promoter activity following CREB3L3 silencing and hepcidin promoter mutation in HepG2 cells. Creb3l3 knockout suckling and young-adult mice showed a prominent serum and hepatic iron accumulation, respectively, due to impaired hepcidin mRNA expression which progressively returned to normal level in adult mice. Interestingly, upon iron challenge, while the upstream BMP/SMAD signaling pathway controlling hepcidin was equally responsive in both strains, hepcidin gene expression was impaired in knockout mice and more iron accumulated in the liver. Accordingly, hepcidin gene response to BMP6 was blunted in primary CREB-H knockout hepatocytes and in HepG2 cells transfected with CREB-H siRNA or carrying a hepcidin promoter mutated in the CREB-H binding site. In conclusion, CREB-H has a role in maintaining the homeostatic balance of iron traffic through hepcidin during the critical postnatal period and in response to iron challenge. KEY MESSAGES: CREB-H KO mice develop liver iron overload shortly after weaning that normalizes in adulthood. CHEB-H is involved in hepcidin gene response to oral iron in vivo. CREB-H loss hampers hepcidin promoter response to BMP6. CREB-H is a key stress-sensor controlling hepcidin gene transcription in physiologic and pathophysiologic states.
    MeSH term(s) Mice ; Animals ; Hepcidins ; Liver/metabolism ; Iron/metabolism ; Bone Morphogenetic Protein 6/genetics ; Bone Morphogenetic Protein 6/metabolism ; Mice, Knockout ; Gene Expression ; Cyclic AMP Response Element-Binding Protein/metabolism
    Chemical Substances Hepcidins ; Iron (E1UOL152H7) ; Bone Morphogenetic Protein 6 ; Creb3l3 protein, mouse ; Cyclic AMP Response Element-Binding Protein
    Language English
    Publishing date 2023-07-26
    Publishing country Germany
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1223802-8
    ISSN 1432-1440 ; 0946-2716
    ISSN (online) 1432-1440
    ISSN 0946-2716
    DOI 10.1007/s00109-023-02344-1
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: A small molecule redistributes iron in ferroportin-deficient mice and patient-derived primary macrophages.

    Ekaputri, Stella / Choi, Eun-Kyung / Sabelli, Manuela / Aring, Luisa / Green, Kelsie J / Chang, JuOae / Bao, Kai / Choi, Hak Soo / Iwase, Shigeki / Kim, Jonghan / Corradini, Elena / Pietrangelo, Antonello / Burke, Martin D / Seo, Young Ah

    Proceedings of the National Academy of Sciences of the United States of America

    2022  Volume 119, Issue 26, Page(s) e2121400119

    Abstract: Deficiencies of the transmembrane iron-transporting protein ferroportin (FPN1) cause the iron misdistribution that underlies ferroportin disease, anemia of inflammation, and several other human diseases and conditions. A small molecule natural product, ... ...

    Abstract Deficiencies of the transmembrane iron-transporting protein ferroportin (FPN1) cause the iron misdistribution that underlies ferroportin disease, anemia of inflammation, and several other human diseases and conditions. A small molecule natural product, hinokitiol, was recently shown to serve as a surrogate transmembrane iron transporter that can restore hemoglobinization in zebrafish deficient in other iron transporting proteins and can increase gut iron absorption in FPN1-deficient flatiron mice. However, whether hinokitiol can restore normal iron physiology in FPN1-deficient animals or primary cells from patients and the mechanisms underlying such targeted activities remain unknown. Here, we show that hinokitiol redistributes iron from the liver to red blood cells in flatiron mice, thereby increasing hemoglobin and hematocrit. Mechanistic studies confirm that hinokitiol functions as a surrogate transmembrane iron transporter to release iron trapped within liver macrophages, that hinokitiol-Fe complexes transfer iron to transferrin, and that the resulting transferrin-Fe complexes drive red blood cell maturation in a transferrin-receptor-dependent manner. We also show in FPN1-deficient primary macrophages derived from patients with ferroportin disease that hinokitiol moves labile iron from inside to outside cells and decreases intracellular ferritin levels. The mobilization of nonlabile iron is accompanied by reductions in intracellular ferritin, consistent with the activation of regulated ferritin proteolysis. These findings collectively provide foundational support for the translation of small molecule iron transporters into therapies for human diseases caused by iron misdistribution.
    MeSH term(s) Animals ; Cation Transport Proteins/deficiency ; Ferritins/metabolism ; Humans ; Iron/metabolism ; Macrophages/metabolism ; Mice ; Monoterpenes/metabolism ; Transferrin/metabolism ; Tropolone/analogs & derivatives ; Tropolone/metabolism ; Zebrafish/metabolism
    Chemical Substances Cation Transport Proteins ; Monoterpenes ; Transferrin ; metal transporting protein 1 ; Tropolone (7L6DL16P1T) ; Ferritins (9007-73-2) ; Iron (E1UOL152H7) ; beta-thujaplicin (U5335D6EBI)
    Language English
    Publishing date 2022-06-22
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 209104-5
    ISSN 1091-6490 ; 0027-8424
    ISSN (online) 1091-6490
    ISSN 0027-8424
    DOI 10.1073/pnas.2121400119
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Human macrophage ferroportin biology and the basis for the ferroportin disease.

    Sabelli, Manuela / Montosi, Giuliana / Garuti, Cinzia / Caleffi, Angela / Oliveto, Stefania / Biffo, Stefano / Pietrangelo, Antonello

    Hepatology (Baltimore, Md.)

    2017  Volume 65, Issue 5, Page(s) 1512–1525

    Abstract: Ferroportin (FPN1) is the sole iron exporter in mammals, but its cell-specific function and regulation are still elusive. This study examined FPN1 expression in human macrophages, the cells that are primarily responsible on a daily basis for plasma iron ... ...

    Abstract Ferroportin (FPN1) is the sole iron exporter in mammals, but its cell-specific function and regulation are still elusive. This study examined FPN1 expression in human macrophages, the cells that are primarily responsible on a daily basis for plasma iron turnover and are central in the pathogenesis of ferroportin disease (FD), the disease attributed to lack-of-function FPN1 mutations. We characterized FPN1 protein expression and traffic by confocal microscopy, western blotting, gel filtration, and immunoprecipitation studies in macrophages from control blood donors (donor) and patients with either FPN1 p.A77D, p.G80S, and p.Val162del lack-of-function or p.A69T gain-of-function mutations. We found that in normal macrophages, FPN1 cycles in the early endocytic compartment does not multimerize and is promptly degraded by hepcidin (Hepc), its physiological inhibitor, within 3-6 hours. In FD macrophages, endogenous FPN1 showed a similar localization, except for greater accumulation in lysosomes. However, in contrast with previous studies using overexpressed mutant protein in cell lines, FPN1 could still reach the cell surface and be normally internalized and degraded upon exposure to Hepc. However, when FD macrophages were exposed to large amounts of heme iron, in contrast to donor and p.A69T macrophages, FPN1 could no longer reach the cell surface, leading to intracellular iron retention.
    Conclusion: FPN1 cycles as a monomer within the endocytic/plasma membrane compartment and responds to its physiological inhibitor, Hepc, in both control and FD cells. However, in FD, FPN1 fails to reach the cell surface when cells undergo high iron turnover. Our findings provide a basis for the FD characterized by a preserved iron transfer in the enterocytes (i.e., cells with low iron turnover) and iron retention in cells exposed to high iron flux, such as liver and spleen macrophages. (Hepatology 2017;65:1512-1525).
    MeSH term(s) Animals ; Case-Control Studies ; Cation Transport Proteins/deficiency ; Hep G2 Cells ; Hepcidins/metabolism ; Humans ; Iron/metabolism ; Macrophages/metabolism ; Mice
    Chemical Substances Cation Transport Proteins ; HAMP protein, human ; Hepcidins ; metal transporting protein 1 ; Iron (E1UOL152H7)
    Language English
    Publishing date 2017-03-22
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 604603-4
    ISSN 1527-3350 ; 0270-9139
    ISSN (online) 1527-3350
    ISSN 0270-9139
    DOI 10.1002/hep.29007
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Gluconeogenic signals regulate iron homeostasis via hepcidin in mice.

    Vecchi, Chiara / Montosi, Giuliana / Garuti, Cinzia / Corradini, Elena / Sabelli, Manuela / Canali, Susanna / Pietrangelo, Antonello

    Gastroenterology

    2013  Volume 146, Issue 4, Page(s) 1060–1069

    Abstract: Background & aims: Hepatic gluconeogenesis provides fuel during starvation, and is abnormally induced in obese individuals or those with diabetes. Common metabolic disorders associated with active gluconeogenesis and insulin resistance (obesity, ... ...

    Abstract Background & aims: Hepatic gluconeogenesis provides fuel during starvation, and is abnormally induced in obese individuals or those with diabetes. Common metabolic disorders associated with active gluconeogenesis and insulin resistance (obesity, metabolic syndrome, diabetes, and nonalcoholic fatty liver disease) have been associated with alterations in iron homeostasis that disrupt insulin sensitivity and promote disease progression. We investigated whether gluconeogenic signals directly control Hepcidin, an important regulator of iron homeostasis, in starving mice (a model of persistently activated gluconeogenesis and insulin resistance).
    Methods: We investigated hepatic regulation of Hepcidin expression in C57BL/6Crl, 129S2/SvPas, BALB/c, and Creb3l3-/- null mice. Mice were fed a standard, iron-balanced chow diet or an iron-deficient diet for 9 days before death, or for 7 days before a 24- to 48-hour starvation period; liver and spleen tissues then were collected and analyzed by quantitative reverse-transcription polymerase chain reaction and immunoblot analyses. Serum levels of iron, hemoglobin, Hepcidin, and glucose also were measured. We analyzed human hepatoma (HepG2) cells and mouse primary hepatocytes to study transcriptional control of Hamp (the gene that encodes Hepcidin) in response to gluconeogenic stimuli using small interfering RNA, luciferase promoter, and chromatin immunoprecipitation analyses.
    Results: Starvation led to increased transcription of the gene that encodes phosphoenolpyruvate carboxykinase 1 (a protein involved in gluconeogenesis) in livers of mice, increased levels of Hepcidin, and degradation of Ferroportin, compared with nonstarved mice. These changes resulted in hypoferremia and iron retention in liver tissue. Livers of starved mice also had increased levels of Ppargc1a mRNA and Creb3l3 mRNA, which encode a transcriptional co-activator involved in energy metabolism and a liver-specific transcription factor, respectively. Glucagon and a cyclic adenosine monophosphate analog increased promoter activity and transcription of Hamp in cultured liver cells; levels of Hamp were reduced after administration of small interfering RNAs against Ppargc1a and Creb3l3. PPARGC1A and CREB3L3 bound the Hamp promoter to activate its transcription in response to a cyclic adenosine monophosphate analog. Creb3l3-/- mice did not up-regulate Hamp or become hypoferremic during starvation.
    Conclusions: We identified a link between glucose and iron homeostasis, showing that Hepcidin is a gluconeogenic sensor in mice during starvation. This response is involved in hepatic metabolic adaptation to increased energy demands; it preserves tissue iron for vital activities during food withdrawal, but can cause excessive iron retention and hypoferremia in disorders with persistently activated gluconeogenesis and insulin resistance.
    MeSH term(s) Animals ; Binding Sites ; Blood Glucose/metabolism ; Cation Transport Proteins/metabolism ; Cyclic AMP Response Element-Binding Protein/deficiency ; Cyclic AMP Response Element-Binding Protein/genetics ; Disease Models, Animal ; Gluconeogenesis ; Hemoglobins/metabolism ; Hep G2 Cells ; Hepatocytes/metabolism ; Hepcidins/blood ; Homeostasis ; Humans ; Insulin Resistance ; Iron/blood ; Liver/metabolism ; Male ; Mice ; Mice, 129 Strain ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Mice, Knockout ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; Phosphoenolpyruvate Carboxykinase (GTP)/genetics ; Phosphoenolpyruvate Carboxykinase (GTP)/metabolism ; Promoter Regions, Genetic ; RNA Interference ; Signal Transduction ; Spleen/metabolism ; Starvation/blood ; Starvation/genetics ; Time Factors ; Transcription Factors/genetics ; Transcription Factors/metabolism ; Transcription, Genetic ; Transfection ; Up-Regulation
    Chemical Substances Blood Glucose ; Cation Transport Proteins ; Creb3l3 protein, mouse ; Cyclic AMP Response Element-Binding Protein ; Hamp protein, mouse ; Hemoglobins ; Hepcidins ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; Ppargc1a protein, mouse ; Transcription Factors ; metal transporting protein 1 ; Iron (E1UOL152H7) ; Phosphoenolpyruvate Carboxykinase (GTP) (EC 4.1.1.32)
    Language English
    Publishing date 2013-12-17
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 80112-4
    ISSN 1528-0012 ; 0016-5085
    ISSN (online) 1528-0012
    ISSN 0016-5085
    DOI 10.1053/j.gastro.2013.12.016
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Ferroportin is a monomer in vivo in mice.

    Pignatti, Elisa / Mascheroni, Laura / Sabelli, Manuela / Barelli, Samuele / Biffo, Stefano / Pietrangelo, Antonello

    Blood cells, molecules & diseases

    2005  Volume 36, Issue 1, Page(s) 26–32

    Abstract: Ferroportin (FPN) is the main iron export protein in mammals. The actual structure of FPN in vivo and the pathogenesis of ferroportin-related disease are unknown. We aimed at studying the structure and biochemical properties of FPN in mouse tissues that ... ...

    Abstract Ferroportin (FPN) is the main iron export protein in mammals. The actual structure of FPN in vivo and the pathogenesis of ferroportin-related disease are unknown. We aimed at studying the structure and biochemical properties of FPN in mouse tissues that are key for iron homeostasis during various iron manipulations in vivo. We performed glycosylation and oligomerization studies in spleen and liver extracts from mice fed a standard, iron-deprived or iron-enriched diet for 5 months. Purification by affinity chromatography and sucrose gradient show that FPN is not part of a large multiprotein complex. Dietary manipulations did not affect the monomeric status of the native or denatured protein. The glycosylation studies showed that ferroportin is digested by peptide: N-glycosidase F but not by endoglycosidase H. The same results were obtained using protein extracts from iron-deficient or iron-loaded mice. In conclusion, our studies indicate that mouse FPN, regardless of the tissue iron status, is glycosylated but not enriched in mannose residues, and that exists mainly in monomeric form. The latter finding may have important implications for understanding the pathogenesis of the disease due to ferroportin mutations.
    MeSH term(s) Animals ; Cation Transport Proteins/chemistry ; Cation Transport Proteins/isolation & purification ; Cation Transport Proteins/metabolism ; Glycoside Hydrolases/chemistry ; Glycosylation ; Iron Overload/metabolism ; Iron Overload/pathology ; Liver/metabolism ; Liver/pathology ; Male ; Mice ; Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase/chemistry ; Protein Processing, Post-Translational ; Spleen/metabolism ; Spleen/pathology
    Chemical Substances Cation Transport Proteins ; metal transporting protein 1 ; Glycoside Hydrolases (EC 3.2.1.-) ; Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase (EC 3.5.1.52)
    Language English
    Publishing date 2005-12-27
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1237083-6
    ISSN 1096-0961 ; 1079-9796
    ISSN (online) 1096-0961
    ISSN 1079-9796
    DOI 10.1016/j.bcmd.2005.11.001
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Hepcidin expression does not rescue the iron-poor phenotype of Kupffer cells in Hfe-null mice after liver transplantation.

    Garuti, Cinzia / Tian, Yinghua / Montosi, Giuliana / Sabelli, Manuela / Corradini, Elena / Graf, Rolf / Ventura, Paolo / Vegetti, Alberto / Clavien, Pierre-Alain / Pietrangelo, Antonello

    Gastroenterology

    2010  Volume 139, Issue 1, Page(s) 315–22.e1

    Abstract: Background & aims: Hemochromatosis is a common hereditary disease caused by mutations in HFE and characterized by increased absorption of iron in the intestine. However, the intestine does not appear to be the site of mutant HFE activity in the disease; ...

    Abstract Background & aims: Hemochromatosis is a common hereditary disease caused by mutations in HFE and characterized by increased absorption of iron in the intestine. However, the intestine does not appear to be the site of mutant HFE activity in the disease; we investigated the role of the liver-the source of the iron regulatory hormone hepcidin-in pathogenesis in mice.
    Methods: We exchanged livers between Hfe wild-type (+/+) and Hfe null (-/-) mice by orthotopic liver transplantation (OLT) and assessed histopathology, serum and tissue iron parameters, and hepatic hepcidin messenger RNA expression.
    Results: At 6-8 months after OLT, Hfe(-/-) mice that received Hfe(-/-) livers maintained the hemochromatosis phenotype: iron accumulation in hepatocytes but not Kupffer cells (KC), increased transferrin levels, and low levels of iron in the spleen. Hfe(+/+) mice that received Hfe(-/-) livers had increased levels of iron in serum and liver and low levels of iron in spleen. However, they did not develop the iron-poor KCs that characterize hemochromatosis: KCs appeared iron rich, although hepatic hepcidin expression was low. Transplantation of Hfe(+/+) livers into Hfe(-/-) mice prevented hepatic iron accumulation but did not return spleen and plasma levels of iron to normal; KCs still appeared to be iron poor, despite normal hepcidin expression.
    Conclusions: In Hfe(-/-) mice, transplantation of livers from Hfe(+/+) mice reversed the iron-loading phenotype associated with hemochromatosis (regardless of Hfe expression in intestine). However, KCs still had low levels of iron that were not affected by hepatic hepcidin expression. These findings indicate an independent, iron-modifying effect of HFE in KCs.
    MeSH term(s) Animals ; Antimicrobial Cationic Peptides/physiology ; Hemochromatosis Protein ; Hepcidins ; Histocompatibility Antigens Class I/physiology ; Iron/metabolism ; Kupffer Cells/physiology ; Liver/metabolism ; Liver Transplantation ; Macrophages/physiology ; Male ; Membrane Proteins/physiology ; Mice ; Phenotype
    Chemical Substances Antimicrobial Cationic Peptides ; Hamp1 protein, mouse ; Hemochromatosis Protein ; Hepcidins ; Hfe protein, mouse ; Histocompatibility Antigens Class I ; Membrane Proteins ; Iron (E1UOL152H7)
    Language English
    Publishing date 2010-07
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 80112-4
    ISSN 1528-0012 ; 0016-5085
    ISSN (online) 1528-0012
    ISSN 0016-5085
    DOI 10.1053/j.gastro.2010.03.043
    Database MEDical Literature Analysis and Retrieval System OnLINE

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