UNDERSTANDING THE ROLE OF RETINOL DEHYDROGENASES RDH11 AND RDH12 IN VISION

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 视黄醇脱氢酶RDH12基因被鉴定为Leber先天性黑色素沉着症的致病基因，Leber先天性黑色素沉着症是最早和最严重的遗传性视网膜营养不良。RDH12的生理作用尚不清楚。我们假设RDH12使光感受器在氧化应激过程中产生的有毒分子失活。我们还假设密切相关的酶RDH11具有相同的功能。强光诱导光感受器的氧化应激和脂质过氧化，导致有毒的4-羟基壬烯醛(4-HNE)的形成。4-HNE与蛋白质形成加合物，破坏重要的细胞功能。在强光照射下，加合物在感光器凋亡之前积聚在感光器中。RDH11和RDH12在体外被证明可以减少4-HNE，我们发现他们保护培养的细胞和光感受器免受4-HNE诱导的加合物的形成和凋亡。 以下具体目标将使我们能够进一步检验我们的假设。目的1：研究RDH11和RDH12在体外和小鼠视网膜中对4-HNE的催化活性。目的：确定RDH11和RDH12在体内是否对4-HNE蛋白加合物的形成和光感受器的凋亡具有保护作用。目的3：验证RDH11在小鼠视网膜中补偿RDH12的假说。如果我们成功地证明RDH11和RDH12的生理作用是使光感受器内节段的4-HNE解毒，这将对临床产生影响，因为它将为RDH12突变导致的进行性视力丧失患者的治疗提供一种策略。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The retinol dehydrogenase RDH12 was identified as a disease-causing gene for Leber Congenital Amaurosis, the earliest and most severe inherited retinal dystrophy. The physiological role of RDH12 is unknown. We hypothesize that RDH12 inactivates toxic molecules produced during oxidative stress in photoreceptors. We also hypothesize that the closely related enzyme, RDH11, has the same function. Bright light induces oxidative stress and lipid peroxidation in photoreceptors, leading to the formation of toxic 4-hydroxynonenal (4-HNE). 4-HNE forms adduct with proteins disrupting important cellular functions. Adducts accumulate in photoreceptors during bright light exposure prior to photoreceptor apoptosis. RDH11 and RDH12 were shown to reduce 4-HNE in vitro and we found evidences that they protect cultured cells and photoreceptors against 4-HNE-induced adduct formation and apoptosis. The following specific aims will allow us to further test our hypothesis. Aim 1: Characterize the catalytic activities of RDH11 and RDH12 towards 4-HNE in vitro and in mouse retina. Aim 2: Determine whether RDH11 and RDH12 are protective against the formation of 4-HNE-protein adducts and apoptosis of photoreceptors in vivo. Aim 3: Test the hypothesis that RDH11 compensates for RDH12 in the mouse retina. If we successfully demonstrate that the physiological role of RDH11 and RDH12 is to detoxify 4-HNE in photoreceptor inner segments, this will have a clinical impact because it will provide a strategy for the treatment of patients with a progressive loss of vision due to RDH12 mutations.