Protein Nitration in Retinal Light Damage

在哺乳动物视网膜光感受器细胞死亡的形态学和功能的变化已经被观察到在光暴露后。人们对光损伤的分子机制以及光照射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光感受器变性。此外，初步的蛋白质组学研究表明，光暴露诱导蛋白质硝化并改变蛋白质表达水平。这一提议的假设是，光暴露导致蛋白质硝化，改变蛋白质的功能和介导光感受器细胞死亡。通过蛋白质组学研究来评价强光照射对大鼠视网膜蛋白硝化和表达的体内影响。具体目的是：1)确定大鼠视网膜光诱导一氧化氮合酶（NOS）的表达、NO的产生和硝基酪氨酸的形成；2)确定大鼠全视网膜和杆外段夜间暴露蛋白表达水平和硝化蛋白的变化；3)表征光暴露诱导LEDGF的结构变化。结果将揭示蛋白质的硝化目标和蛋白质的上下调节光暴露。该结果将有助于更好地理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.