Department of Ophthalmology, College of Medicine, University of Florida, 1600 SW Archer Road, 32610, Gainesville, FL, USA,
Adv Exp Med Biol. 2014;801:711-8. doi: 10.1007/978-1-4614-3209-8_89.
The rd6 mouse is a natural model of an RPE-based (retinal pigment epithelium) autosomal recessive retinitis pigmentosa (RP) caused by mutations in the Mfrp (membrane-type frizzled related protein) gene. Previously, we showed that subretinal delivery of the wild-type mouse Mfrp mediated by a tyrosine-capsid mutant scAAV8 (Y733F) vector prevented photoreceptor cell death, and rescued retinal function as assessed by electroretinography. In this study, we describe the effect of gene therapy on the retinal structure and function in rd6 mice using a quadruple (Y272, 444, 500, 730F) tyrosine-capsid mutant scAAV2 viral vector delivered subretinally at postnatal day 14 (P14). We show that therapy is effective at slowing the photoreceptor degeneration, and in preventing the characteristic accumulation of abnormal phagocytic cells in the subretinal space. MFRP expression as driven by the ubiquitous chicken β-actin (smCBA) promoter in treated rd6 mice was found predominantly in the RPE apical membrane and the entire length of its microvilli, as well as in the photoreceptor inner segments, suggesting a potential interaction with actin filaments. In spite of preserving retinal morphology, the effects of gene therapy on retinal function were minimal, suggesting that the scAAV8 (Y733F) vector may be more efficient for the treatment of RP caused by Mfrp mutations.
rd6 小鼠是一种由 Mfrp（膜型卷曲相关蛋白）基因突变引起的 RPE 型（视网膜色素上皮）常染色体隐性视网膜色素变性（RP）的天然模型。此前，我们发现通过酪氨酸衣壳突变 scAAV8（Y733F）载体进行的野生型小鼠 Mfrp 的视网膜下递送可防止光感受器细胞死亡，并通过视网膜电图评估来挽救视网膜功能。在这项研究中，我们使用在出生后第 14 天（P14）进行视网膜下递送的四重（Y272、444、500、730F）酪氨酸衣壳突变 scAAV2 病毒载体描述了基因治疗对 rd6 小鼠视网膜结构和功能的影响。我们表明，该疗法可有效减缓光感受器变性，并防止异常吞噬细胞在视网膜下空间的特征性积累。在治疗后的 rd6 小鼠中，由普遍存在的鸡β-肌动蛋白（smCBA）启动子驱动的 MFRP 表达主要在 RPE 顶膜及其微绒毛的全长以及光感受器内节中发现，表明与肌动蛋白丝可能存在潜在相互作用。尽管保留了视网膜形态，但基因治疗对视网膜功能的影响很小，这表明 scAAV8（Y733F）载体可能更适合治疗由 Mfrp 突变引起的 RP。
