Mowat Freya M, Occelli Laurence M, Bartoe Joshua T, Gervais Kristen J, Bruewer Ashlee R, Querubin Janice, Dinculescu Astra, Boye Sanford L, Hauswirth William W, Petersen-Jones Simon M
Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State UniversityEast Lansing, MI, United States.
Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State UniversityRaleigh, NC, United States.
Front Neurosci. 2017 Jun 20;11:342. doi: 10.3389/fnins.2017.00342. eCollection 2017.
Despite mutations in the rod phosphodiesterase 6-alpha () gene being well-recognized as a cause of human retinitis pigmentosa, no definitive treatments have been developed to treat this blinding disease. We performed a trial of retinal gene augmentation in the mutant dog using delivery by capsid-mutant adeno-associated virus serotype 8, previously shown to have a rapid onset of transgene expression in the canine retina. Subretinal injections were performed in 10 dogs at 29-44 days of age, and electroretinography and vision testing were performed to assess functional outcome. Retinal structure was assessed using color fundus photography, spectral domain optical coherence tomography, and histology. Immunohistochemistry was performed to examine transgene expression and expression of other retinal genes. Treatment resulted in improvement in dim light vision and evidence of rod function on electroretinographic examination. Photoreceptor layer thickness in the treated area was preserved compared with the contralateral control vector treated or uninjected eye. Improved rod and cone photoreceptor survival, rhodopsin localization, cyclic GMP levels and bipolar cell dendrite distribution was observed in treated areas. Some adverse effects including foci of retinal separation, foci of retinal degeneration and rosette formation were identified in both and control vector injected regions. This is the first description of successful gene augmentation for Pde6a retinitis pigmentosa in a large animal model. Further studies will be necessary to optimize visual outcomes and minimize complications before translation to human studies.
尽管视杆磷酸二酯酶6-α（Pde6a）基因突变被公认为是人类视网膜色素变性的病因，但尚未开发出明确的治疗方法来治疗这种致盲疾病。我们在Pde6a突变犬中进行了一项视网膜基因增强试验，使用衣壳突变腺相关病毒血清型8进行递送，先前已证明其在犬视网膜中具有快速的转基因表达。在10只29至44日龄的犬中进行了视网膜下注射，并进行了视网膜电图和视力测试以评估功能结果。使用彩色眼底照相、光谱域光学相干断层扫描和组织学评估视网膜结构。进行免疫组织化学以检查转基因表达和其他视网膜基因的表达。治疗导致暗光视力改善以及视网膜电图检查显示视杆功能的证据。与对侧对照载体处理或未注射的眼睛相比，治疗区域的感光层厚度得以保留。在治疗区域观察到视杆和视锥感光细胞存活率提高、视紫红质定位、环磷酸鸟苷水平和双极细胞树突分布改善。在Pde6a和对照载体注射区域均发现了一些不良反应，包括视网膜分离灶、视网膜变性灶和玫瑰花结形成。这是在大型动物模型中首次成功描述针对Pde6a视网膜色素变性的基因增强。在转化为人体研究之前，需要进一步研究以优化视觉结果并将并发症降至最低。
