Mol. Anal. of Microdissected Cataractous Human Lenses

描述（由申请人提供）：蛋氨酸亚砜还原酶通过直接还原氧化蛋氨酸残基修复氧化应激损伤的能力是独一无二的，并且可能在晶状体老化和白内障形成中发挥关键作用。在人的晶状体中检测到MsrA活性，并且人的晶状体蛋白的氧化蛋氨酸含量随着年龄的增长而增加，在与年龄相关的白内障中，与清澈的人的晶状体相比，氧化蛋氨酸含量高达60%。这一提议将验证蛋氨酸亚砜还原酶保护晶状体免受氧化应激损伤的假设，以及Msr水平和/或活性的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)建立人和小鼠晶状体中蛋氨酸亚砜还原酶的特征、水平、活性和亚细胞定位模式；(2)蛋氨酸亚砜还原酶保护晶状体免受氧化应激的能力将被确定；(3)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的关系。这些目标将通过对体外和体内能力进行功能测试的综合方法来实现

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.