Protein Nitration in Retinal Light Damage

已经观察到光暴露后哺乳动物视网膜中感光细胞死亡的形态和功能变化。关于光损伤的分子机制以及由光暴露引起的蛋白质修饰知之甚少。一氧化氮（NO）是体内硝化剂的生物前体分子，被认为介导光诱导的感光细胞变性。此外，初步的蛋白质组学研究表明，光暴露诱导蛋白质硝化和改变蛋白质表达水平。该提议的假设是，光暴露导致蛋白质硝化，从而改变蛋白质的功能并介导感光细胞死亡。表达蛋白质组学研究以评估强光暴露对大鼠视网膜蛋白质硝化和表达的体内效应。具体目标是：1）测定大鼠视网膜中光诱导的一氧化氮合酶（NOS）表达、NO产生和硝基酪氨酸形成，2）鉴定整个大鼠视网膜和视杆外段中蛋白质表达水平和通过夜间暴露被硝化的蛋白质的变化，和3）表征光暴露诱导的LEDGF的结构变化。结果将揭示硝化作用的蛋白质靶点和受光照调节的蛋白质。这些结果将有助于更好地了解视网膜光损伤的相关机制。

Morphological and functional changes in the mammalian retina to photoreceptor cell death have been observed following light exposure. Little is known about the molecular mechanism of light damage nor about protein modifications caused by light exposure. Nitric oxide (NO), which is biological precursor molecule for nitrating agents in vivo has been suggested to mediate light-induced photoreceptor degeneration. In addition, preliminary proteomic studies suggest that light exposure induces protein nitration and changes protein expression levels. The hypothesis of this proposal is that light exposure causes protein nitration that alter the function of the protein and mediate photoreceptor cell death. Proteomic studies are expressed to evaluate the in vivo effect of intense light exposure on rat retinal protein nitration and expression. The specific aims are: 1) Determine light-induced nitric oxide synthase (NOS) expression, NO production and nitrotyrosine formation in rat retina, 2) Identify changes in protein expression levels and proteins which are nitrated by night exposure in whole rat retina and rod outer segments, and 3) Characterize structural changes in LEDGF induced by light exposure. Results will reveal protein targets of nitration and proteins up and down regulated by light exposure. The results will lead to a better understanding of the mechanisms associated with retinal light damage.