Retinal Iron Homeostasis in Health and Disease

健康和疾病中的视网膜铁稳态

• 批准号: 8035342
• 负责人: VADIVEL GANAPATHY
• 金额: $ 35.55万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8035342
• 关键词: Acquired Immunodeficiency Syndrome; Acute Retinal Necrosis Syndrome; Address; Adolescent; Affect; Age; Age related macular degeneration; Animal Model; BMP2 gene; BMP4; BMP6 gene; Blindness; Blood-Retinal Barrier; Bone Morphogenetic Proteins; Brain; Cataract; Caucasians; Caucasoid Race; Cell Differentiation process; Cell Proliferation; Cell Surface Proteins; Cell physiology; Cells; Ceruloplasmin; Characteristics; Code; Complement Factor H; Cytomegalovirus; Cytomegalovirus Infections; Data; Dependence; Development; Disease; Down-Regulation; Drusen; E-Cadherin; Enzymes; Epithelial; Event; Exhibits; FarGo; Frequencies; Functional disorder; Gene Expression; Genes; Glaucoma; Goals; HLA Antigens; Health; Hereditary Disease; Hereditary hemochromatosis; Herpesvirus 1; Homeostasis; Human; In Vitro; Infection; Injury; Iron; Iron Metabolism Disorders; Iron Overload; Iron-Regulatory Proteins; Kidney; Laboratories; Link; Liver; Maintenance; Mediating; Molecular; Morphology; Muller' s cell; Mus; Mutate; Mutation; Neural Retina; Nutrient; Organ; Oxidative Stress; Pancreas; Pathogenesis; Pathology; Patients; Phenotype; Photoreceptors; Play; Proliferative Vitreoretinopathy; Proteins; RPE65 protein; Regulation; Regulator Genes; Reporting; Retina; Retinal; Retinal Degeneration; Retinal Diseases; Retinal Ganglion Cells; Retinitis; Role; Signal Transduction; Stem cells; Structure; Testing; Time; Tissues; Toxic effect; Transgenic Mice; Transplant Recipients; Up-Regulation; Virus; Virus Diseases; Wild Type Mouse; age related; base; design; epithelial to mesenchymal transition; ganglion cell; hepcidin; in vivo; insight; interest; metal transporting protein 1; mouse model; novel; oxidative damage; pluripotency; public health relevance; receptor; transcription factor; transferrin receptor 2

DESCRIPTION (provided by applicant): The primary goal of this project is to test the hypothesis that retina is a target tissue for iron overload and iron-induced oxidative damage in hereditary hemochromatosis (HHC), the most prevalent genetic disease characterized by iron accumulation in systemic organs. Mutations in HFE [Histocompatability leukocyte antigen class I-like protein involved in iron (FE) homeostasis], a gene coding for a cell surface protein involved in the regulation of iron homeostasis, are responsible for ~85% cases of this disease (classical HHC). The remaining cases arise from mutations in four other genes (hemojuvelin, hepcidin, transferrin receptor 2, and ferroportin), also coding for iron-regulatory proteins. Mutations in hemojuvelin (HJV) cause juvenile HHC in which excessive iron accumulation occurs in organs at a much younger age than in classical HHC. Surprisingly, little is known on whether retina is affected in this disease. We have shown for the first time that all five HHC-associated genes are expressed in the retina: Hfe exclusively in RPE; Hjv in RPE and neural retina; hepcidin and ferroportin in RPE, Muller cells, and photoreceptor cells; and transferrin receptor 2 throughout the retina. More importantly, we have evidence for age-dependent morphological changes in the retina in a mouse model of classical HHC (Hfe-/- mouse). In addition, we found that Hfe-/- RPE cells exhibit a hyperproliferative phenotype compared to wild type RPE cells. These findings are novel and point to an interesting link between iron status and cell proliferation. Our studies also show that the expression of Hfe, Hjv, and hepcidin is markedly altered in RPE and in retina as a result of infection with cytomegalovirus (CMV) and herpes simplex virus-1 (HSV1). These interesting and important findings form the basis for the proposed studies. Aim 1 is to test the hypothesis that HHC is associated with iron overload in RPE and retina with functional consequences. This will be tested using two different mouse models, one representing the classical HHC (Hfe-/- mouse) and the other representing the juvenile HHC (Hjv-/- mouse). Aim 2 is to test the hypothesis that deletion of HFE and HJV has consequences that go far beyond iron accumulation and associated oxidative damage. Studies under this specific aim will include examination of the molecular events responsible for the hyperproliferative phenotype of Hfe-/- RPE cells as well as for the epithelial-to-mesenchymal transition in Hjv-/- RPE cells and for the disruption of BMP signaling and its consequences in Hjv-/- retina. Aim 3 is to test the hypothesis that infection of RPE and retina with CMV and HSV1 disrupts iron homeostasis by modulating the expression of iron-regulatory genes. This will be investigated using primary cultures of retinal cells in vitro and with wild type and HHC mouse models in vivo. These studies will provide important insight into the molecular mechanisms involved in the maintenance of iron homeostasis in the retina in health and disease and on the involvement of the retina in HHC, the most prevalent genetic disease in Caucasians. PUBLIC HEALTH RELEVANCE: Hereditary hemochromatosis (HHC) is the most prevalent genetic disease characterized by excessive iron accumulation in various systemic organs, but whether the iron status in the retina is affected in this disease is not known. It is known however, that excessive iron accumulation in the retina causes oxidative damage and retinal degeneration. Studies proposed in this project will investigate the HHC-associated changes in the iron status, structure, and morphology of the retina and the functional consequences using transgenic mouse models of HHC, and assess the involvement of various iron-regulatory proteins in RPE and the retina during infection with cytomegalovirus and herpes simplex virus-1.

描述（由申请人提供）：该项目的主要目标是检验以下假设：视网膜是铁超载和铁诱导的遗传性血色素沉着症（HHC）的氧化损伤的靶组织，这是最普遍的遗传疾病，它是由全身器官中铁积累的最普遍的遗传疾病。 HFE的突变[组织性白细胞抗原I类样蛋白参与铁（Fe）稳态]，这是一种编码用于调节铁稳态调节的细胞表面蛋白的基因，负责该疾病的85％病例（经典HHC）。其余的病例来自其他四个基因（Hemojuvelin，hepcidin，转铁蛋白受体2和铁蛋白）的突变，也编码铁调节蛋白。血果林（HJV）的突变导致少年HHC，其中比经典HHC年龄要年轻得多的器官中发生过多的铁积累。令人惊讶的是，在这种疾病中是否受到视网膜的影响知之甚少。我们首次表明，所有五个HHC相关的基因均在视网膜中表达：HFE仅在RPE中。 RPE和神经视网膜中的HJV； RPE，穆勒细胞和感光细胞中的肝素和铁蛋白；整个视网膜中的转铁蛋白受体2。更重要的是，我们有证据表明在经典HHC的小鼠模型（HFE - / - 小鼠）中，视网膜中依赖年龄的形态变化。此外，我们发现与野生型RPE细胞相比，HFE - / - RPE细胞表现出高增殖表型。这些发现是新颖的，并指出了铁状态与细胞增殖之间的有趣联系。我们的研究还表明，HFE，HJV和肝素的表达在RPE和视网膜中因巨细胞病毒（CMV）（CMV）和疱疹Simplex Virus-1（HSV1）而受到显着改变。这些有趣而重要的发现构成了拟议研究的基础。目的1是测试HHC与RPE和视网膜中的铁超载相关的假设，并具有功能后果。这将使用两种不同的鼠标模型进行测试，一种代表经典HHC（HFE - / - 鼠标），另一个代表少年HHC（HJV - / - 鼠标）。目的2是测试HFE和HJV缺失的假设，其后果远远超出了铁的积累和相关的氧化损伤。在此特定目的下的研究将包括检查HFE - / - RPE细胞的高增殖表型的分子事件，以及HJV - / - RPE细胞中的上皮到间质转变以及BMP信号及其在HJV - /-RETINA中的影响。目的3是测试以下假设：RPE和视网膜用CMV和HSV1感染通过调节铁调节基因的表达来破坏铁稳态。这将在体外使用视网膜细胞的原代培养物以及体内的野生型和HHC小鼠模型进行研究。这些研究将为维持视网膜维持健康和疾病中的铁稳态以及视网膜在H​​HC中的参与而涉及的分子机制提供重要见解，这是高加索人最普遍的遗传疾病。 公共卫生相关性：遗传性血色素沉着症（HHC）是最普遍的遗传疾病，其特征是各种全身器官中铁积累过多，但是在这种疾病中，视网膜中的铁状态是否受到影响。然而，众所周知，视网膜中的铁积累过多会导致氧化损伤和视网膜变性。该项目中提出的研究将研究视网膜的铁状态，结构和形态的变化以及使用HHC的转基因小鼠模型的功能后果，并评估在RPE中的各种铁调节蛋白在RPE和视网膜中的参与，以及在感染过程中与大细胞病毒和疱疹Simplex Virus一起感染。