Role of aquaporins in mammalian lens development,transparency and homeostasis

项目摘要 被称为水通道蛋白(AQPs)的跨膜水通道在维持 无血管的透明度、生物力学、屈光度梯度(环)和内稳态 哺乳动物的晶状体。为了获得营养和消除新陈代谢浪费，晶状体创造了一个 涉及水通道蛋白、离子和溶质转运体以及共转运体的微循环电流。突变 在纤维细胞特异性AQP0中，该基因的敲除(KO)导致晶状体白内障，而 正常情况下小鼠晶状体上皮细胞特异性AQP1未引起任何明显的缺陷 生理条件。然而，AQP1KO和AQP5KO小鼠的晶状体发生了渗透 高血糖应激条件下的肿胀和白内障。几种晶状体蛋白，如珠状 细丝蛋白(CP49和细丝蛋白)、晶体蛋白和连接蛋白与AQP0相互作用，可能是为了 调节其功能。这里的目标是阐明三个AQP的机制， AQP0、AQP1和AQP5在诱导和维持晶状体透明度、环和 在正常和有压力的情况下(如糖尿病)的动态平衡。我们的长期目标是 为预防和治疗白内障作出贡献。主要的假设是：水通道蛋白发挥作用 在晶状体微循环、生物力学、环和渗透调节中的关键作用，以及 它们的功能改变(S)会导致白内障。 具体目标是：1.探索完整的和递减的梯度的组合是否 AQP0末端裂解形式从皮质到细胞核的梯度增加，需要 在体内维持晶状体的透明度、生物力学和环状。2.测试两种水是否 渗透性和CTCA功能对于维持晶状体透明度、生物力学和 环，以及探讨AQP0在体外、体内和体外的分子机制 在晶状体纤维细胞之间施加CTCA。3.探讨AQP0、AQP1和AQP5的调控 在维持晶状体渗透调节和环的透明度、生物力学方面发挥重要作用 以及在正常和糖尿病高血糖应激条件下的动态平衡。目标将是 酌情使用结构-功能方法，并进行显微镜检查、细胞培养、 器官培养以及细胞学、生物力学、生化、生理学和分子生物学 在开发动物模型的同时进行生物实验。拟议的研究具有 有可能收集关于下列组织所发挥作用的机制的重要数据和关键信息 AQP在晶状体透明度和动态平衡中的作用。这一结果可能会为小说提供新的方向 治疗白内障和眼内其他水通道蛋白相关疾病的治疗策略， 如干眼、青光眼、视网膜脱离、黄斑变性和视网膜病变。

Project Summary Transmembrane water channels known as aquaporins (AQPs) play significant roles in maintaining transparency, biomechanics, refractive index gradient (RING) and homeostasis in the avascular mammalian lens. To get nourishment and eliminate metabolic wastes, the lens creates a microcirculatory current involving AQPs, ion- and solute transporters, and cotransporters. Mutations in fiber cell-specific AQP0, and knockout (KO) of the gene resulted in lens cataract whereas those of epithelial cell-specific AQP1 did not cause any obvious defects in mouse lens under normal physiological conditions. However, lenses of AQP1 KO and AQP5 KO mice developed osmotic swelling and cataract under hyperglycemic stress conditions. Several lens proteins such as beaded filament proteins (CP49 and filensin), crystallins and connexins interact with AQP0, possibly to modulate its functions. The goal here is to elucidate the mechanisms by which the three AQPs, AQP0, AQP1 and AQP5, play important roles to elicit and maintain lens transparency, RING and homeostasis under normal and stressful conditions (such as diabetes). Our long term objective is to contribute to the prevention and treatment of cataracts. The main hypothesis is: Aquaporins play critical roles in the lens microcirculation, biomechanics, RING and osmoregulation, and alterations in their function(s) lead to cataracts. The Specific Aims are to: 1. To explore whether a combination of a decreasing gradient of intact and an increasing gradient of end cleaved forms of AQP0, from the cortex to the nucleus, is required for maintaining lens transparency, biomechanics and RING in vivo. 2. To test whether both water permeability and CTCA functions are critical for maintaining lens transparency, biomechanics and RING, as well as, to explore in vitro, in vivo and ex vivo the molecular mechanism by which AQP0 exerts CTCA between the lens fiber cells. 3. To investigate if regulation of AQP0, AQP1 and AQP5 plays significant roles in maintaining lens osmoregulation and RING for transparency, biomechanics and homeostasis under normal and diabetic hyperglycemic stress conditions. The objectives will be pursued using structure-function approach, as appropriate, and performing microscopy, cell culture, organ culture as well as cytological, biomechanical, biochemical, physiological, and molecular biological experiments along with developing an animal model. The proposed studies have the potential to gather significant data and key information on the mechanistics of the roles played by AQPs in lens transparency and homeostasis. The results could offer new directions for novel therapeutic strategies for the treatment of cataracts and other aquaporin-related diseases in the eye, such as dry eye, glaucoma, retinal detachment, macular degeneration and retinopathy.