Interphotoreceptor Retinoid-Binding Protein Protects Retinoids from Photodegradation
Interphotoreceptor Retinoid-Binding Protein Protects Retinoids from Photodegradation
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DOI：
10.1111/php.12416
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发表时间：
2015-03-01
影响因子：
3.3
通讯作者：
Tsin, Andrew T.
中科院分区：
文献类型：
--
作者：
Gonzalez-Fernandez, Federico;Betts-Obregon, Brandi;Tsin, Andrew T.
视黄醇在光下迅速降解成多种光产物。值得注意的是，视觉周期类视黄醇在光感受器、视网膜色素上皮和米勒神经胶质细胞之间交换时可以逃避光降解。在光感受器间基质内，全反式视黄醇、11-顺式视黄醇和视黄醛通过光感受器间视黄醇结合蛋白（IRBP）结合。除了在类视黄醇运输和靶向中的作用外，IRBP 是否还具有光保护功能？采用HPLC评价IRBP保护全反式和11-顺式视黄醇在白炽灯（0至8842Wcm(-2)）下免于光降解的能力；时间为0-60分钟，bIRBP：视黄醇摩尔比为1:1至1:5。 bIRBP 可以显着防止全反式和 11-顺式视黄醇的快速光降解。该效果在整个测试的光强度范围内都很显着，并且延伸至 bIRBP：视黄醇比例为 1:5。鉴于视网膜持续暴露在光线下以及外层视网膜的高氧化应激，我们的结果表明IRBP可能通过减少全反式和11-顺式视黄醇的光降解而在视觉周期中发挥重要的保护作用。 IRBP 的这种作用在视锥视觉周期的高通量条件下尤其重要。
Retinol degrades rapidly in light into a variety of photoproducts. It is remarkable that visual cycle retinoids can evade photodegradation as they are exchanged between the photoreceptors, retinal pigment epithelium and Muller glia. Within the interphotoreceptor matrix, all-trans retinol, 11-cis retinol and retinal are bound by interphotoreceptor retinoid-binding protein (IRBP). Apart from its role in retinoid trafficking and targeting, could IRBP have a photoprotective function? HPLC was used to evaluate the ability of IRBP to protect all-trans and 11-cis retinols from photodegradation when exposed to incandescent light (0 to 8842Wcm(-2)); time periods of 0-60min, and bIRBP: retinol molar ratios of 1:1 to 1:5. bIRBP afforded a significant prevention of both all-trans and 11-cis retinol to rapid photodegradation. The effect was significant over the entire light intensity range tested, and extended to the bIRBP: retinol ratio 1:5. In view of the continual exposure of the retina to light, and the high oxidative stress in the outer retina, our results suggest IRBP may have an important protective role in the visual cycle by reducing photodegradation of all-trans and 11-cis retinols. This role of IRBP is particularly relevant in the high flux conditions of the cone visual cycle.