Tyrosine-Mutant AAV8 Delivery of Human MERTK Provides Long-Term Retinal Preservation in RCS Rats
Tyrosine-Mutant AAV8 Delivery of Human MERTK Provides Long-Term Retinal Preservation in RCS Rats
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DOI：
10.1167/iovs.11-8831
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发表时间：
2012-04-01
影响因子：
4.4
通讯作者：
Hauswirth, William W.
中科院分区：
文献类型：
--
作者：
Deng, Wen-Tao;Dinculescu, Astra;Hauswirth, William W.
目的. RCS大鼠中Mertk的缺乏导致RPE吞噬功能缺陷、视网膜下腔中外段（OS）碎片的积累以及随后的光感受器死亡。先前在RCS大鼠中利用Mertk基因替代疗法的研究为治疗这种形式的隐性视网膜色素变性（RP）提供了概念证明;然而，对视网膜功能的有益作用是短暂的。在本研究中，我们评估了使用酪氨酸突变型AAV 8衣壳递送MERTK转基因是否可以导致比先前证实的更稳健和更长期的治疗结果。在出生后第2天视网膜下施用表达由RPE选择性启动子驱动的人MERTK cDNA的AAV 8 Y 733 F载体。在治疗后4个月和8个月进行功能和形态学分析。视网膜血管和Muller细胞活化分别通过定量脱细胞毛细血管和胶质细胞酸性蛋白免疫染色进行分析。治疗眼的视网膜电图反应超过野生型水平的三分之一，即使在8个月时，注射区域的OS也保持良好。在治疗的眼睛中，至少8个月的治疗证明了RPE吞噬作用的拯救，视网膜血管变性的预防和Muller细胞活化的抑制。这项研究描述了一个更长，更强大的功能和形态救援比以前的研究。我们还首次证明了AAV 8突变体衣壳血清型载体具有用于RPE特异性基因递送的实质性治疗潜力。这些结果表明，酪氨酸突变型AAV 8载体有望用于治疗MERTK相关RP患者。（Invest Ophthalmol维斯科学。2012;53：1895-1904）DOI：10.1167/iovs.11-8831
PURPOSE. The absence of Mertk in RCS rats results in defective RPE phagocytosis, accumulation of outer segment (OS) debris in the subretinal space, and subsequent death of photoreceptors. Previous research utilizing Mertk gene replacement therapy in RCS rats provided proof of concept for treatment of this form of recessive retinitis pigmentosa (RP); however, the beneficial effects on retinal function were transient. In the present study, we evaluated whether delivery of a MERTK transgene using a tyrosine-mutant AAV8 capsid could lead to more robust and longer-term therapeutic outcomes than previously reported.METHODS. An AAV8 Y733F vector expressing a human MERTK cDNA driven by a RPE-selective promoter was administrated subretinally at postnatal day 2. Functional and morphological analyses were performed at 4 months and 8 months post-treatment. Retinal vasculature and Muller cell activation were analyzed by quantifying acellular capillaries and glial fibrillary acidic protein immunostaining, respectively.RESULTS. Electroretinographic responses from treated eyes were more than one-third of wild-type levels and OS were well preserved in the injection area even at 8 months. Rescue of RPE phagocytosis, prevention of retinal vasculature degeneration, and inhibition of Muller cell activation were demonstrated in the treated eyes for at least 8 months.CONCLUSIONS. This research describes a longer and much more robust functional and morphological rescue than previous studies. We also demonstrate for the first time that an AAV8 mutant capsid serotype vector has a substantial therapeutic potential for RPE-specific gene delivery. These results suggest that tyrosine-mutant AAV8 vectors hold promise for the treatment of individuals with MERTK-associated RP. (Invest Ophthalmol Vis Sci. 2012;53:1895-1904) DOI:10.1167/iovs.11-8831