Retinal Iron Homeostasis in Health and Disease

健康和疾病中的视网膜铁稳态

• 批准号: 7889446
• 负责人: VADIVEL GANAPATHY
• 金额: $ 38.2万
• 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/7889446
• 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; Histocompatibility; 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）：该项目的主要目的是验证视网膜是遗传性血色素沉着症（HHC）中铁超载和铁诱导氧化损伤的靶组织的假设，HHC是最常见的遗传性疾病，其特征是铁在全身器官中积累。HFE（参与铁（FE）稳态的组织相容性白细胞抗原i类蛋白）是一种参与铁稳态调节的细胞表面蛋白的基因编码，其突变可导致约85%的HHC病例（经典HHC）。其余的病例是由另外四个基因的突变引起的（血凝素、肝磷脂、转铁蛋白受体2和铁转运蛋白），这些基因也编码铁调节蛋白。血少年蛋白（HJV）突变引起少年型HHC，其中器官中铁的过量积累发生在比经典HHC年轻得多的年龄。令人惊讶的是，人们对视网膜是否受到这种疾病的影响知之甚少。我们首次发现所有五种hhc相关基因都在视网膜中表达：Hfe只在RPE中表达；Hjv在RPE和神经视网膜；RPE、Muller细胞和光感受器细胞中的hepcidin和铁转运蛋白；转铁蛋白受体2遍布视网膜。更重要的是，我们有证据表明经典HHC小鼠模型（Hfe-/-小鼠）视网膜的年龄依赖性形态学变化。此外，我们发现与野生型RPE细胞相比，Hfe-/- RPE细胞表现出超增殖表型。这些发现是新颖的，并指出了铁状态和细胞增殖之间的有趣联系。我们的研究还表明，由于巨细胞病毒（CMV）和单纯疱疹病毒-1 （HSV1）的感染，Hfe、Hjv和hepcidin在RPE和视网膜中的表达明显改变。这些有趣而重要的发现构成了拟议研究的基础。目的1是验证HHC与RPE和视网膜铁超载相关的假设，并对其功能产生影响。这将使用两种不同的小鼠模型进行测试，一种代表经典HHC （Hfe-/-小鼠），另一种代表幼年HHC （Hjv-/-小鼠）。目的2是验证HFE和HJV缺失的后果远远超出铁积累和相关氧化损伤的假设。在这一特定目标下的研究将包括检查导致Hfe-/- RPE细胞超增殖表型的分子事件，以及Hjv-/- RPE细胞从上皮到间质转化的分子事件，以及Hjv-/-视网膜中BMP信号的破坏及其后果。目的3是验证CMV和HSV1感染RPE和视网膜通过调节铁调控基因的表达来破坏铁稳态的假设。这将通过体外视网膜细胞原代培养和野生型和HHC小鼠体内模型进行研究。这些研究将为健康和疾病中视网膜铁稳态维持的分子机制，以及白种人中最普遍的遗传性疾病HHC中视网膜的参与提供重要的见解。