Protein Nitration in Retinal Light Damage

光暴露后，哺乳动物视网膜由于光感受器细胞死亡而发生的形态和功能变化已被观察到。人们对光损伤的分子机制知之甚少，也不知道光暴露引起的蛋白质修饰。一氧化氮(NO)是体内硝化试剂的生物前体分子，被认为是介导光诱导的光感受器退化的分子。此外，初步的蛋白质组学研究表明，光照诱导蛋白质硝化并改变蛋白质的表达水平。这一提议的假设是，光暴露导致蛋白质硝化，从而改变蛋白质的功能，并介导光感受器细胞的死亡。蛋白质组学研究是为了评估强光暴露对大鼠视网膜蛋白硝化和表达的体内影响。其具体目的是：1)测定光诱导的大鼠视网膜一氧化氮合酶(NOS)的表达、NO的产生和硝基酪氨酸的形成；2)确定夜间暴露对整个视网膜和视杆外节硝化的蛋白质表达水平和蛋白质的变化；3)表征光暴露诱导的LEDGF的结构变化。结果将揭示硝化的蛋白质靶标和受光照射上调和下调的蛋白质。这一结果将有助于更好地理解与视网膜光损伤相关的机制。

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.