Mol. Anal. of Microdissected Cataractous Human Lenses

描述(由申请人提供)：蛋氨酸亚砜还原酶具有独特的能力，能够通过直接还原氧化的蛋氨酸残基来修复氧化应激损伤，并可能在晶状体老化和白内障形成中发挥关键作用。已经在人类晶状体中检测到MSRA活性，并且人类晶状体蛋白的氧化蛋氨酸含量随着年龄的增长而增加，在老年性白内障中，相对于透明的人类晶状体，其含量高达60%。这项提议将检验一种假设，即蛋氨酸亚砜还原酶保护晶状体免受氧化应激损伤，以及MSR水平和/或活性降低与晶状体蛋氨酸氧化增加、晶状体损伤和白内障有关。为了验证这一假设：(1)将建立人和小鼠晶状体中蛋氨酸亚砜还原酶的身份、水平、活性和亚细胞定位模式；(2)将确定蛋氨酸亚砜还原酶防御晶状体免受氧化应激的能力；以及(3)将在晶状体老化和老年性白内障中建立蛋氨酸亚砜还原酶活性与蛋氨酸氧化之间的关系。这些目标将通过从功能上测试体外和体内能力的综合方法来实现 该公司研究了用于保护晶状体免受氧化应激损伤的蛋氨酸亚砜还原酶的活性，并直接检测了实际人类晶状体和白内障中的蛋氨酸亚砜还原酶活性。这项工作的可行性得到了人类晶状体中三个独立的蛋氨酸亚砜还原酶基因的初步鉴定和空间特征的支持，并证明了这些基因中至少有一个称为MSRA，可以直接防御晶状体细胞免受氧化应激损伤。

DESCRIPTION (provided by applicant): Methionine sulfoxide reductases are unique in their ability to actually repair oxidative stress damage through the direct reduction of oxidized methionine residues and are likely to play key roles in lens aging and cataract formation. MsrA activity has been detected in the human lens, and the oxidized methionine content of human lens proteins increases with age reaching levels as high as 60% in age-related cataract relative to clear human lenses. This proposal will test the hypothesis that methionine sulfoxide reductases defend the lens against oxidative stress damage and that decreased Msr levels and/or activities are associated with increased oxidation of lens methionines, lens damage and cataract. To test this hypothesis: (1) The identities, levels, activities and sub-cellular localization patterns of methionine sulfoxide reductases of the human and mouse lens will be established; (2) The ability of methionine sulfoxide reductases to defend the lens against oxidative-stress will be determined; and (3) the relationship between methionine sulfoxide reductase activity and methionine oxidation will be established in lens aging and age-related cataract. These aims will be accomplished using an integrative approach that functionally tests the in vitro and in vivo ability of methionine sulfoxide reductases to defend the lens against oxidative stress damage and directly examines methionine sulfoxide reductase activities in actual human lenses and cataracts. The feasibility of this work is supported by the initial identification and spatial characterization of three separate methionine sulfoxide reductase genes in the human lens and the demonstration that at least one of these genes, called MsrA, can directly defend lens cells against oxidative stress damage.