Ferroxidases in RPE iron transport

RPE 铁转运中的铁氧化酶

• 批准号: 6931023
• 负责人: JOSHUA L DUNAIEF
• 金额: $ 31.7万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6931023
• 关键词: Adenoviridae; angiogenesis; biological models; confocal scanning microscopy; ferroxidase; gene induction /repression; gene targeting; genetically modified animals; immunoelectron microscopy; in situ hybridization; ion transport; iron; laboratory mouse; model design /development; protein localization; retina degeneration; retinal pigment epithelium; transfection /expression vector; vascular endothelial growth factors

DESCRIPTION (provided by applicant): Iron is necessary in the retina for oxidative phosphorylation, membrane biogenesis and many other metabolic processes, but can also produce oxidative stress if improperly regulated, leading to cell death. Iron plays a significant role in retinal degeneration, as follows: 1) Iron toxicity causes retinal degeneration following direct entry of iron into the eye carried by an intraocular foreign body 2) Iron has been implicated in the RCS rats' retinal degeneration, in which the mechanism of iron overload is indirect. 3) Human AMD retinas have more iron than age-matched controls, suggesting that iron overload may play a role in AMD pathogenesis. 4) Inherited defects in iron metabolism result in retinal degeneration in Friedreich's ataxia, pantothenate kinase associated neuropathy, and aceruloplasminemia. The focus of the current proposal is to understand the functions in ocular iron homeostasis of the ferroxidases ceruloplasmin (Cp) and its homologue hephaestin (Heph). In Aim 1, the retinal localization of Cp and Heph will be assessed. In Aim 2, an RPE-specific Heph knockout will be generated. This will determine whether RPE Heph expression is necessary for RPE iron homeostasis. It should also provide a mouse model of retinal degeneration that like our Cp-/-Heph-/- mice, has subretinal neovascularization, but unlike Cp-/-Heph-/- mice, has a normal lifespan. In addition it will provide reagents for generating RPE-specific knockouts for the eye research community. In Aim 3, the retinal degeneration in Cp-/-Heph-/- and Cp-/-RPE-specific Heph-/- mice will be characterized. Both oxidative stress and mechanisms of neovascularization will be studied. In Aim 4 an RPE in vitro system will be used to determine whether Cp and Heph mediate RPE iron import or export, and assess the polarity of transport. These studies are important because: 1) The mechanism of retinal degeneration in aceruloplasminemia is not known. 2) The retinal functions of Cp and Heph are not known. 3) Our preliminary studies show that Cp-/-Heph-/- mice will provide a model for several features of AMD, including subretinal neovascularization. 4) These mice will provide a model of neurodegeneration caused by age-dependent increases in iron levels, which recent reports suggest may contribute to the pathogenesis of Alzheimer's and Parkinson's diseases and AMD. 5) These mice will provide the opportunity to test iron chelators and antioxidants as potential treatments/preventions for those age-related diseases.

描述（由申请人提供）：在视网膜中必须进行铁，以用于氧化磷酸化，膜生物发生和许多其他代谢过程，但如果受到不当调节，也可能产生氧化应激，从而导致细胞死亡。铁在视网膜变性中起着重要作用，如下：1）铁毒性导致铁毒性直接进入由眼内异物携带的眼睛后的视网膜变性。 3）人类AMD视网膜的铁比年龄匹配的对照更多，这表明铁超负荷可能在AMD发病机理中起作用。 4）铁代谢中的遗传缺陷导致弗里德里希共济失调，泛素激酶相关的神经病和促脂蛋白血症的视网膜变性。当前建议的重点是了解铁氧化酶Ceruloplasmin（CP）的眼铁稳态及其同源性hephaestin（HEPH）的功能。在AIM 1中，将评估CP和HEPH的视网膜定位。在AIM 2中，将产生特定于RPE的HEPH淘汰赛。这将确定RPE HEPH表达是否需要RPE铁稳态。它还应该提供视网膜变性的小鼠模型，与我们的CP - / - HEPH - / - 小鼠一样，具有视网膜下新生血管形成，但与CP - / - HEPH - / - 小鼠不同，其寿命正常。此外，它将为眼睛研究界生成RPE特异性淘汰的试剂。在AIM 3中，将表征CP - / - HEP-/ - 和CP - / - rPE特异性HEPH - / - 小鼠的视网膜变性。将研究氧化应激和新血管形成的机制。在AIM 4中，RPE体外系统将用于确定CP和HEPH是否介导了RPE铁的进口或出口，并评估运输的极性。这些研究很重要，因为：1）尚不清楚腺泡性血症视网膜变性的机理。 2）CP和HEPH的视网膜功能尚不清楚。 3）我们的初步研究表明，cp - / - heph - / - 小鼠将为AMD的多种特征（包括视网膜下新生血管化）提供模型。 4）这些小鼠将提供由铁水平依赖年龄增加引起的神经变性的模型，最近的报道可能有助于阿尔茨海默氏症和帕金森氏病和AMD的发病机理。 5）这些小鼠将为铁螯合剂和抗氧化剂作为对年龄相关疾病的潜在疗法/预防措施提供机会。