Peroxiredoxin 6 and Cataractogenesis

过氧化还原蛋白 6 和白内障发生

• 批准号: 7372897
• 负责人: DHIRENDRA P SINGH
• 金额: $ 37.13万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7372897
• 关键词: Actins; Age; Aging; Antioxidants; Apoptosis; Attenuated; Binding; Biological; Biological Assay; Biological Markers; Biological Models; Blindness; Calpain; Cataract; Cell Aging; Cell Survival; Cells; Combined Modality Therapy; Crystalline Lens; Data; Degenerative Disorder; Disease; Elements; Environment; Epithelial Cells; Etiology; Event; Exhibits; Eye diseases; Figs - dietary; Foundations; Functional disorder; Gene Expression; Genes; Genetic Transcription; Goals; Growth Factor; In Vitro; Knockout Mice; Lead; Letters; Measurement; Mediating; Membrane; Modeling; Molecular; Monitor; Mus; NF-kappa B; Nuclear Extract; Organ; Oxidation-Reduction; Oxidative Stress; Paraquat; Peroxidases; Phospholipase A2; Play; Process; Proteins; Rattus; Reactive Oxygen Species; Recombinants; Regulation; Reporting; Repression; Role; Signal Transduction; Site; Site-Directed Mutagenesis; Smooth Muscle Actin Staining Method; Stress; System; Techniques; Testing; Therapeutic; Therapeutic Uses; Time; Tissues; Transactivation; Transfection; age related; aged; antioxidant therapy; attenuation; base; cell age; cell injury; clinical application; feeding; in vivo; insight; interest; lens; normal aging; novel; peroxiredoxin; prevent; promoter; research study; sound

DESCRIPTION (provided by applicant): Recent evidence implicates that the oxidative stress plays a role in the etiology of Age-Related Cataract, and suggests that aged lens cells are prone to this damage due to reduced expression of antioxidants. Because ocular lens is constantly exposed to environmental stress, it continuously generates reactive oxygen species (ROS), if not removed, increased formation and local accumulation of ROS in the cellular microenvironment causes lens cell damage-by initiating wide-spectrum of deleterious signaling and if this situation prolongs may lead to cataractogenesis. Peroxiredoxin 6 (PRDX6), a 'moonlighting protein' with both GSH peroxidase and aiPLA2 (acidic Ca2+independent phospholipase A2) activities, is highly expressed in lens. Our studies have shown diminution of PRDX6 expression and higher intracellular ROS levels in lens cells during aging. Using targeted inactivation of Prdx6 gene in mice, we found that Prdx6-depleted lenses and/or lens epithelial cells (LECs) contain elevated levels of ROS and bio-activeTGF21; exhibit phenotypic changes with overmodulation of TGF21 inducible genes such as 1-SM-actin and 2ig-h3, and these genes are implicated in pathophysiology of cataractogenesis. We envisage a vicious feed-forward-process (ROS?? TGF?1??ROS = overmodulation of genes??) taking place within the local microenvironment of aging LECs or LECs facing oxidative stress, and therefore, we hypothesized that by blocking ROS mediated deleterious signaling should reduce progression of cataractogenesis, by interrupting the vicious cycle initiated by locally high levels of ROS and activated TGF21 within cellular microenvironment. We believe that these events are causally related, i.e., that the environmental stress and age-related reduction in PRDX6 in lens tissues leads to ROS-induced damage of membrane or cytosolic factors, as a consequence of this damage, cell homeostatic system fails. The over all goal of this proposal, therefore, is to unveil the roles of oxidative stress in pathophisiology of cataract formation and to show PRDX6 ability in treating/delaying cataractogenesis through three specific aims: 1) Understand the functional significance of PRDX6 and its regulatory role during oxidative stress and aging. 2) Assess the antioxidant potential of PRDX6 in protecting cells facing oxidative stress in vitro and in vivo using TAT-HA- PRDX6 to cargoing PRDX6 protein in Prdx6-/- depleted mice and mice with Paraquat-induced oxidative stress as well as Shumiya cataract rat (SCR), and assess whether cataract progression is slowed by PRDX6. 3) Investigate the regulatory mechanisms of PRDX6 in normal and aging LECs and cells under oxidative stress and define role(s) of downstream redox signaling in controlling its gene transcription. These studies should provide novel insights into the role of oxidative stress in cataract formation and will provide a foundation for rational use of antioxidant based therapeutics for treating or preventing/delaying cataractogenesis. A common disorder of the eye, Age-Related Cataract (ARC) is among the leading causes of blindness. Although evidence suggests a role for reactive oxygen species-driven oxidative stress in the progression and etiology of age-related degenerative diseases including ARC, the mechanism of oxidative stress-induced deleterious signaling, a cause of cellular damage that leads to the disease state, is not clear. Thus clinical application of antioxidant therapy or combination of therapies has been at best equivocal. Using eye lens as a model for age-associated disorders, we will unveil the underlying mechanism involved in the pathophysiology of tissues/organs during oxidative stress or aging. The proposed studies will provide a sound scientific basis for developing an antioxidant-based therapy or combination of therapies for preventing cataractogenesis and age-associated degenerative diseases in general.

描述（由申请人提供）：最近的证据表明，氧化应激在晶状体相关性白内障的病因学中起作用，并表明老化的透镜细胞由于抗氧化剂表达减少而易于发生这种损伤。由于眼透镜持续暴露于环境应激，其持续产生活性氧（ROS），如果不去除，ROS在细胞微环境中的增加的形成和局部积累通过启动广谱有害信号而导致透镜细胞损伤，并且如果这种情况恶化，可能导致白内障发生。过氧化物氧还蛋白6（Peroxiredoxin 6，PRDX 6）是一种具有GSH过氧化物酶和aiPLA 2（酸性钙离子非依赖性磷脂酶A2）活性的兼职蛋白，在透镜中高度表达。我们的研究表明，在老化过程中，透镜细胞中PRDX 6表达减少，细胞内ROS水平升高。利用Prdx 6基因的靶向失活，我们发现Prdx 6缺失的晶状体和/或透镜上皮细胞（LEC）含有升高水平的ROS和生物活性TGF 21;表现出表型变化，TGF 21诱导基因如1-SM-actin和2 ig-h3过度调节，并且这些基因与白内障发生的病理生理学有关。我们设想一个恶性前馈过程（ROS？？转化生长因子1？？ROS =基因的过度调节？？）在老化LEC或面临氧化应激的LEC的局部微环境中发生，因此，我们假设通过阻断ROS介导的有害信号传导，通过中断由细胞微环境中局部高水平的ROS和活化的TGF 21引发的恶性循环，可以减少白内障发生的进展。我们认为这些事件是有因果关系的，即，透镜组织中PRDX 6的环境应激和年龄相关的减少导致ROS诱导的膜或胞质因子的损伤，作为这种损伤的结果，细胞稳态系统失效。因此，本提案的总体目标是揭示氧化应激在白内障形成的病理生理学中的作用，并通过三个具体目标显示PRDX 6在治疗/延迟白内障发生中的能力：1）了解PRDX 6的功能意义及其在氧化应激和衰老期间的调节作用。2)使用TAT-HA-PRDX 6在体外和体内评估PRDX 6在保护面临氧化应激的细胞中的抗氧化潜力，以在Prdx 6-/-缺失小鼠和具有百草枯诱导的氧化应激的小鼠以及Shumiya白内障大鼠（SCR）中携带PRDX 6蛋白，并评估PRDX 6是否减缓白内障进展。3)研究PRDX 6在正常和老化LEC和氧化应激下的细胞中的调节机制，并确定下游氧化还原信号在控制其基因转录中的作用。这些研究将为氧化应激在白内障形成中的作用提供新的见解，并将为合理使用基于抗氧化剂的治疗方法治疗或预防/延迟白内障提供基础。眼相关性白内障（ARC）是一种常见的眼部疾病，是导致失明的主要原因之一。尽管有证据表明活性氧驱动的氧化应激在包括ARC在内的年龄相关退行性疾病的进展和病因学中发挥作用，但氧化应激诱导的有害信号传导机制（导致疾病状态的细胞损伤的原因）尚不清楚。因此，抗氧化治疗或联合治疗的临床应用充其量是模棱两可的。以眼透镜为模型研究年龄相关性疾病，我们将揭示氧化应激或衰老过程中组织/器官病理生理学的潜在机制。拟议的研究将为开发基于抗氧化剂的治疗或预防白内障和一般年龄相关退行性疾病的联合治疗提供可靠的科学基础。