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这样的假设：视网膜是遗传性血色素沉着病（HHC）中铁过载和铁诱导的氧化损伤的靶组织，HHC是最常见的遗传性疾病，其特征是铁在全身器官中积聚。 HFE（参与铁 (FE) 稳态的组织相容性白细胞抗原 I 类蛋白）突变是一种编码参与铁稳态调节的细胞表面蛋白的基因，约 85% 的这种疾病（经典 HHC）病例是由 HFE 突变引起的。其余病例是由其他四个基因（血幼素、铁调素、转铁蛋白受体 2 和铁转运蛋白）突变引起的，这些基因也编码铁调节蛋白。血幼素 (HJV) 突变会导致幼年型 HHC，其中器官中发生铁积累过多的年龄比经典 HHC 年轻得多。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。我们首次证明所有五个 HHC 相关基因均在视网膜中表达：Hfe 仅在 RPE 中表达； RPE 和神经视网膜中的 Hjv； RPE、Muller 细胞和感光细胞中的铁调素和铁转运蛋白；以及遍布视网膜的转铁蛋白受体2。更重要的是，我们有证据表明经典 HHC 小鼠模型（Hfe-/- 小鼠）的视网膜存在年龄依赖性形态变化。此外，我们发现与野生型 RPE 细胞相比，Hfe-/- RPE 细胞表现出过度增殖表型。这些发现很新颖，表明铁状态与细胞增殖之间存在有趣的联系。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) 感染，RPE 和视网膜中 Hfe、Hjv 和铁调素的表达显着改变。这些有趣且重要的发现构成了拟议研究的基础。目标 1 是检验以下假设：HHC 与 RPE 和视网膜中的铁超载相关，并产生功能后果。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）。目标 2 是检验以下假设：删除 HFE 和 HJV 所产生的后果远远超出铁积累和相关氧化损伤的范围。这一特定目标下的研究将包括检查导致 Hfe-/- RPE 细胞过度增殖表型、Hjv-/- RPE 细胞中上皮-间质转化以及 BMP 信号传导破坏及其在 Hjv-/- 视网膜中的后果的分子事件。目标 3 是检验以下假设：CMV 和 HSV1 感染 RPE 和视网膜会通过调节铁调节基因的表达来破坏铁稳态。这将使用体外视网膜细胞原代培养物以及体内野生型和 HHC 小鼠模型进行研究。这些研究将为了解健康和疾病中维持视网膜铁稳态的分子机制以及视网膜与 HHC（白种人中最常见的遗传病）的关系提供重要的见解。 公共健康相关性：遗传性血色素沉着病 (HHC) 是最常见的遗传病，其特征是铁在各个全身器官中积累过多，但视网膜中的铁状态是否受到这种疾病的影响尚不清楚。然而，众所周知，视网膜中过多的铁积累会导致氧化损伤和视网膜变性。该项目提出的研究将利用 HHC 转基因小鼠模型研究与 HHC 相关的视网膜铁状态、结构和形态的变化及其功能后果，并评估巨细胞病毒和单纯疱疹病毒 1 感染期间 RPE 和视网膜中各种铁调节蛋白的参与情况。