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1.
铁是人体必需的微量元素,是血红蛋白、肌红蛋白及多种酶的重要组成成分,广泛地参与氧气输运、氧化还原反应、细胞增殖与分化、基因表达调控等基本生命过程。机体铁稳态对生命体新陈代谢的平衡起着至关重要的作用。铁稳态依赖铁吸收、转运和储存、再循环利用等代谢过程共同调节。铁调素(Hepcidin)是铁代谢调节中最关键的调节分子,成熟的铁调素是一个由25个氨基酸组成的功能性小肽类激素,可以通过调节小肠上皮细胞和巨噬细胞表面的相关铁转运蛋白来调控机体内铁的储存和利用。铁调素同时受到机体铁水平的反馈,免疫应答和红细胞生成等因素的共同调节。许多铁代谢疾病、炎症和各种原因引起的贫血与铁调素的异常表达相关。因此,对于铁调素的检测不但可以反映机体的铁代谢状况,结合其他临床指标还能够辅助诊断和有针对性地检测相关疾病的治疗效果。  相似文献   

2.
单核巨噬细胞铁代谢相关蛋白的表达调控   总被引:2,自引:0,他引:2  
人类机体的铁代谢表现为受限制的对外界铁的吸收和有效的机体内的铁的再循环利用,单核巨噬细胞系统通过吞噬衰老的红细胞,储存和释放铁,在机体铁的循环再利用方面起到了重要的作用。因此,单核巨噬细胞系统对整个机体铁稳态的维持非常重要。近年来,随着转铁蛋白受体1(transferrin receptor1,TfR1)、铁蛋白(ferritin,Fn)、二价金属离子转运蛋白1(divalent metal transporter1,DMT1)、膜铁转运蛋白1(ferroportin1,FPN1),以及铁调素(hepcidin)等在单核巨噬细胞系统中功能和调控机制研究的不断深入,日益加深了人们对单核巨噬细胞系统的铁代谢过程和调控机制的了解。该文综述了铁水平、NO以及炎症等因素对单核巨噬细胞系统TfR1、Fn、DMT1、FPN1、hepcidin等蛋白表达的调控及其机制研究的最新进展。  相似文献   

3.
铁调素(hepcidin)是由肝脏分泌的一种肽类激素,它通过改变细胞膜上ferroportin的水平而调节全身铁代谢。Ferroportin是唯一已知的哺乳动物中的铁外排通道,它表达在小肠细胞的基底外侧膜和巨噬细胞的质膜上。铁调素结合ferroportin导致其在溶酶体内降解,从而减少铁从饮食的吸收和巨噬细胞铁的释放。Hemojuvelin(HJV)是一种glycosylphosphatidylinositol(GPI)相连的膜蛋白,它作为骨形态发生蛋白(BMP)的共受体可以激活肝细胞Smad信号通路和铁调素表达。除了表达在细胞膜上,hemojuvelin还可以被切割并分泌到胞外,形成可溶性蛋白。由furin切割产生的可溶性HJV可以选择性地结合到BMP配体,抑制内源性BMP诱导的铁调素表达。TMPRSS6也被认为可以切割细胞膜上HJV并影响铁调素的表达。最近的研究表明,HJV还可能参与脂肪组织对铁代谢的调控。综述了近期对细胞膜HJV和可溶性HJV如何调节铁调素的表达与铁代谢的研究结果,并对这一研究领域需要填补的空白进行了初步探讨。  相似文献   

4.
铁是生物体必需的微量元素。铁缺乏和铁过载均会导致铁代谢紊乱相关疾病,因此有关机体铁水平稳态的调节机制已成为了目前铁代谢领域的研究热点。小肠吸收细胞是调节肠铁吸收、肠铁释放,以及维持机体铁稳态的重要部位。最新的研究表明,铁从小肠吸收细胞基底端释放入血液循环,主要是由膜铁转运蛋白(ferroportin1,Fp1)介导,并在膜铁转运辅助蛋白(haphaestin,Hp)和铜蓝蛋白(ceruloplasmin,Cp)的参与下完成。其中Fp1在小肠铁释放过程中起着至关重要的作用。本文重点阐述铁释放相关蛋白Fp1的作用机制及其调节机制,并详细介绍Fp1基因突变导致的铁代谢相关疾病方面的最新研究讲展。  相似文献   

5.
铁代谢与铁调素hepcidin   总被引:10,自引:0,他引:10  
Fu LJ  Duan XL  Qian ZM 《生理科学进展》2005,36(3):233-236
铁是机体必需的营养元素。然而,铁过载则导致细胞的损伤。由于生物体缺少排泄铁的机制,因而,肠铁吸收的调控便成为维持机体铁稳态的关键。新近研究发现hepcidin对机体铁稳态的调节起着至关重要的作用,被人们称为铁调节激素。Hepcidin主要在肝细胞中合成,之后分泌至血液将体内铁需要的信号传至小肠,调控肠铁的吸收。这一过程主要通过调节小肠铁转运相关蛋白的表达而实现。任何影响hepcidin表达的因素都可能破坏体内的铁平衡,造成铁代谢相关疾病。  相似文献   

6.
用荧光定量PCR法检测鼠RAW264.7巨噬细胞感染与未感染鼠伤寒沙门菌后18种铁穗态相关基因的表达,评估宿主与病原体相互作用中铁稳态效应。研究显示,活的鼠伤寒沙门菌感染巨噬细胞1 h后可以诱导转铁蛋白受体表达,引起细胞内动态铁池相关基因的mRNA水平上长。基因表达分析显示,沙门菌通过诱导铁氧还原酶(Steap3)、铁膜转运蛋白(Dmt1)、铁调节因子Tfr2/Hfe以及铁调节蛋白(Irp1和Irp2)的表达主动吸收铁,而经铁转运蛋白(Fpn1)的铁外流并无明显改变。沙门菌在感染后1h积极地驱动了转铁蛋白介导的铁吸收程序。  相似文献   

7.
王贺阳  李敏 《生命科学》2012,(8):767-774
铁调素(Hepcidin)是由肝细胞分泌的维持人体系统性铁平衡的核心因子,其通过改变细胞膜铁转运蛋白(ferroportin,Fpn)的表达量以调控肠黏膜细胞和巨噬细胞内铁的转出水平,从而决定机体循环铁水平并影响肝脏等主要储铁脏器的铁负荷程度。根据近年来的研究发现,影响Hepcidin表达的主要因素可以归纳为两个方面:一是机体本身对铁的需求,而由于铁本身又是Hb(hemoglobin,血红蛋白)的合成原料以及携氧成份,因此还应包括机体对Hb合成和缺氧的反应,介导因子主要包括携铁转铁蛋白(holo—transferrin,holo—Tf)、促红细胞生成素(erythropoietin,EPO)和缺氧诱导因子-1(hypoxia.inducible factor1,HIF.1);另一则是源于疾病病理过程中相关致病因素、细胞因子、激素等非铁调控因子的改变对其表达调控机制产生的影响,并通过扰乱机体铁稳态加速疾病的发展或加重病情。随着研究资料的积累,糖尿病、部分心血管疾病、酒精性或非酒精性脂肪肝等慢性疾病存在铁过负荷已是不争的事实,多种hepcidin非铁调控因子在代谢紊乱型铁过负荷综合征(sysmetabolic iron overload syndrome)发生过程中的作用受到了广泛重视。对一些常见疾病中引起hepcidin表达变化异常和铁代谢紊乱的非铁因子及其作用机制的研究进展进行综述。  相似文献   

8.
机体铁稳态的维持对正常生理功能至关重要。铁调素和铁调素调节蛋白在维持铁稳态中发挥重要作用。近来,丝氨酸蛋白酶基质-2在铁稳态中的作用越来越受到重视。此外,肥胖与铁缺乏的发生密切相关。一方面,肥胖人群脂肪组织高水平分泌白介素-6(interleukin-6, IL-6)、肿瘤坏死因子-α(tumor necrosis factor-α, TNF-α)以及瘦素等脂肪因子,这些脂肪因子能够调节铁调素和铁调素调节蛋白表达;另一方面,肥胖个体脂肪组织也可直接表达铁调素与铁调素调节蛋白。运动作为一种非侵入性干预手段在调节肥胖与铁缺乏中可能发挥重要作用。本文将对近年来文献进行整理,以期能够为铁稳态维持以及肥胖与铁缺乏的机制提供一些新的视角。  相似文献   

9.
氧和铁这两种元素对生命活动十分重要. 低氧诱导因子(hypoxia-inducible factors, HIFs)作为转录因子,参与一系列靶基因的表达调控以适应低氧. 铁参与 DNA合成、氧气运输、代谢反应等多种细胞活动,过量游离铁会通过Haber-Weiss或 Fenton反应产生毒性自由基. 细胞通过与铁吸收、存储和利用有关的多种铁代谢相 关蛋白之间的协同作用来维持铁稳态. 与铁稳态相关的一些基因是HIFs的靶基因或 者间接受低氧调控,包括转铁蛋白、转铁蛋白受体、二价金属转运体1、铁调素、膜 铁转运蛋白、血浆铜蓝蛋白、铁蛋白等,而胞内铁浓度的改变能影响HIFs的表达. 本文就低氧与铁代谢相关蛋白的关系,尤其是低氧对铁代谢相关蛋白的调节作一综 述.  相似文献   

10.
最近的研究证实,肾小管细胞具有能力表达包括转铁蛋白受体1(transferrin receptor-1,TfR1)、二价金属离子转运蛋白1(divalent metal transporter-1,DMT1)、膜铁转运蛋白1(ferroportin-1,FPN1)、铁调节蛋白(iron regulatory protein,IRP)和铁调素(hepcidin,Hepc)在内的几乎所有铁代谢蛋白.这些蛋白质的存在以及相关研究显示肾脏可能具有排出多余铁的功能,因此对体铁平衡起有十分重要的作用.  相似文献   

11.
红细胞合成是人类和其他脊椎动物最耗铁的生理过程,对机体铁稳态具有重要调节作用。Erythroferrone(ERFE)是红细胞系来源的调节铁调素的主要激素。当机体存在应激性红细胞合成时,ERFE合成增加,铁调素表达受抑,可促进机体铁吸收和储铁动员,满足红细胞合成对铁的需求,但在无效红细胞生成疾病中,通过此作用也导致了铁过载的发生。ERFE抑制肝细胞合成铁调素的作用机制尚不清楚,但至少部分地依赖BMP/SMAD信号通路。ERFE对铁代谢障碍性疾病和红细胞生成紊乱性贫血有重要的诊断及治疗价值。  相似文献   

12.
Intestinal epithelial cells and reticuloendothelial macrophages are, respectively, involved in diet iron absorption and heme iron recycling from senescent erythrocytes, two critical processes of iron homeostasis. These cells appear to use the same transporter, ferroportin (Slc40a1), to export iron. The aim of this study was to compare the localization, expression, and regulation of ferroportin in both duodenal and macrophage cells. Using a high-affinity purified polyclonal antibody, we analyzed the localization and expression of ferroportin protein in the spleen, liver, and duodenum isolated from normal mice as well as from well-characterized mouse models of altered iron homeostasis. Ferroportin was found to be predominantly expressed in enterocytes of the duodenum, in splenic macrophages, and in liver Kupffer cells. Interestingly, the protein species detected in these cells migrated differently on SDS-PAGE. These differences in apparent molecular masses were partly explained by posttranslational complex N-linked glycosylations. In addition, in enterocytes, the transporter was mostly expressed at the basolateral membrane, whereas in bone marrow-derived macrophages, ferroportin was found predominantly localized in the intracellular vesicular compartment. However, some microdomains positive for ferroportin were also detected at the plasma membrane of macrophages. Despite these differences, we observed a parallel upregulation of ferroportin expression in tissue macrophages and enterocytes in response to iron-restricted erythropoiesis, suggesting that iron homeostasis is likely maintained through coordinate expression of the iron exporter in both intestinal and phagocytic cells. Our data also confirm a predominant regulation of ferroportin through systemic regulator(s) likely including hepcidin.  相似文献   

13.
Iron loading inhibits ferroportin1 expression in PC12 cells   总被引:1,自引:0,他引:1  
  相似文献   

14.

Iron is an essential trace element involved in oxidation–reduction reactions, oxygen transport and storage, and energy metabolism. Iron in excess can be toxic for cells, since iron produces reactive oxygen species and is important for survival of pathogenic microbes. There is a fine-tuning in the regulation of serum iron levels, determined by intestinal absorption, macrophage iron recycling, and mobilization of hepatocyte stores versus iron utilization, primarily by erythroid cells in the bone marrow. Hepcidin is the major regulatory hormone of systemic iron homeostasis and is upregulated during inflammation. Hepcidin metabolism is altered in chronic kidney disease. Ferroportin is an iron export protein and mediates iron release into the circulation from duodenal enterocytes, splenic reticuloendothelial macrophages, and hepatocytes. Systemic iron homeostasis is controlled by the hepcidin–ferroportin axis at the sites of iron entry into the circulation. Hepcidin binds to ferroportin, induces its internalization and intracellular degradation, and thus inhibits iron absorption from enterocytes, and iron release from macrophages and hepatocytes. Recent data suggest that hepcidin, by slowing or preventing the mobilization of iron from macrophages, may promote atherosclerosis and may be associated with increased cardiovascular disease risk. This article reviews the current data regarding the molecular and cellular pathways of systemic and autocrine hepcidin production and seeks the answer to the question whether changes in hepcidin translate into clinical outcomes of all-cause and cardiovascular mortality, and cardiovascular and renal end-points.

  相似文献   

15.
Iron metabolism in mammals requires a complex and tightly regulated molecular network. The classical view of iron metabolism has been challenged over the past ten years by the discovery of several new proteins, mostly Fe (II) iron transporters, enzymes with ferro-oxydase (hephaestin or ceruloplasmin) or ferri-reductase (Dcytb) activity or regulatory proteins like HFE and hepcidin. Furthermore, a new transferrin receptor has been identified, mostly expressed in the liver, and the ability of the megalin-cubilin complex to internalise the urinary Fe (III)-transferrin complex in renal tubular cells has been highlighted. Intestinal iron absorption by mature duodenal enterocytes requires Fe (III) iron reduction by Dcytb and Fe (II) iron transport through apical membranes by the iron transporter Nramp2/DMT1. This is followed by iron transfer to the baso-lateral side, export by ferroportin and oxidation into Fe (III) by hephaestin prior to binding to plasma transferrin. Macrophages play also an important role in iron delivery to plasma transferrin through phagocytosis of senescent red blood cell, heme catabolism and recycling of iron. Iron egress from macrophages is probably also mediated by ferroportin and patients with heterozygous ferroportin mutations develop progressive iron overload in liver macrophages. Iron homeostasis at the level of the organism is based on a tight control of intestinal iron absorption and efficient recycling of iron by macrophages. Signalling between iron stores in the liver and both duodenal enterocytes and macrophages is mediated by hepcidin, a circulating peptide synthesized by the liver and secreted into the plasma. Hepcidin expression is stimulated in response to iron overload or inflammation, and down regulated by anemia and hypoxia. Hepcidin deficiency leads to iron overload and hepcidin overexpression to anemia. Hepcidin synthesis in response to iron overload seems to be controlled by the HFE molecule. Patients with hereditary hemochromatosis due to HFE mutation have impaired hepcidin synthesis and forced expression of an hepcidin transgene in HFE deficient mice prevents iron overload. These results open new therapeutic perspectives, especially with the possibility to use hepcidin or antagonists for the treatment of iron overload disorders.  相似文献   

16.
The severity of liver disease and its presentation is thought to be influenced by many host factors. Prominent among these factors is the level of iron in the body. The liver plays an important role in coordinating the regulation of iron homeostasis and is involved in regulating the level of iron absorption in the duodenum and iron recycling by the macrophages. Iron homeostasis is disturbed by several metabolic and genetic disorders, including various forms of hereditary hemochromatosis. This review will focus on liver disease and how it is affected by disordered iron homeostasis, as observed in hereditary hemochromatosis and due to HFE mutations. The types of liver disease covered herein are chronic hepatitis C virus (HCV) infection, alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), end-stage liver disease, hepatocellular carcinoma (HCC) and porphyria cutanea tarda (PCT).  相似文献   

17.
Ferroportin (FPN), the only iron exporter identified to date, participates in iron release from enterocytes and macrophages, regulating its absorption and recycling. We used a murine model of experimental hemolytic anemia to study adaptive changes in the localization of FPN in duodenum, liver, and spleen. FPN was assessed by IHC in healthy and anemic mice using rabbit anti-mouse FPN polyclonal antibodies. Goat-labeled polymer-horseradish peroxidase anti-rabbit Envision+System (DAB) was used as secondary antibody. Tissue iron was studied by Prussian blue iron staining. Anemia evolution and erythropoietic recovery was assessed using conventional hematological tests. Healthy mice showed mainly supranuclear expression of FPN in enterocytes and a weak basolateral expression, whereas in anemic mice, the expression was detected mainly at the basolateral membrane (days 4 and 5). Red pulp macrophages of healthy mice showed FPN-hemosiderin colocalization. In the liver of healthy mice, FPN was mainly cytoplasmic, whereas in anemic mice, it was redistributed to the cell membrane. Our findings clearly show that anemia induces adaptive changes in FPN expression, contributing to anemia restoration by increasing available iron. FPN expression in the membrane is the main pathway of iron release. Our data indicate that iron homeostasis in vivo is maintained through the coordinated expression of this iron exporter in both intestinal and phagocytic cells. (J Histochem Cytochem 57:9–16, 2009)  相似文献   

18.
Iron imports. IV. Hepcidin and regulation of body iron metabolism   总被引:1,自引:0,他引:1  
Hepcidin, a small peptide synthesized in the liver, controls extracellular iron by regulating its intestinal absorption, placental transport, recycling by macrophages, and release from stores. Hepcidin inhibits the cellular efflux of iron by binding to and inducing the degradation of ferroportin, the sole iron exporter in iron-transporting cells. In turn, hepcidin synthesis is increased by iron loading and decreased by anemia and hypoxia. Hepcidin is markedly induced during inflammation, trapping iron in macrophages, decreasing plasma iron concentrations, and contributing to the anemia of inflammation. Hepcidin deficiency due to the dysregulation of its synthesis causes most known forms of hemochromatosis.  相似文献   

19.

Background  

Macrophages are involved in a number of key physiological processes and complex responses such as inflammatory, immunological, infectious diseases and iron homeostasis. These cells are specialised for iron storage and recycling from senescent erythrocytes so they play a central role in the fine tuning of iron balancing and distribution. The comprehension of the many physiological responses of macrophages implies the study of the related molecular events. To this regard, proteomic analysis, is one of the most powerful tools for the elucidation of the molecular mechanisms, in terms of changes in protein expression levels.  相似文献   

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