Sharma Tasneem P, Wiley Luke A, Whitmore S Scott, Anfinson Kristin R, Cranston Cathryn M, Oppedal Douglas J, Daggett Heather T, Mullins Robert F, Tucker Budd A, Stone Edwin M
Stephen A Wynn Institute for Vision Research, Department of Ophthalmology and Visual Science, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
Stem Cell Res. 2017 May;21:58-70. doi: 10.1016/j.scr.2017.03.005. Epub 2017 Mar 18.
Retinitis pigmentosa (RP) is a heterogeneous group of monogenic disorders characterized by progressive death of the light-sensing photoreceptor cells of the outer neural retina. We recently identified novel hypomorphic mutations in the tRNA Nucleotidyl Transferase, CCA-Adding 1 (TRNT1) gene that cause early-onset RP. To model this disease in vitro, we generated patient-specific iPSCs and iPSC-derived retinal organoids from dermal fibroblasts of patients with molecularly confirmed TRNT1-associated RP. Pluripotency was confirmed using rt-PCR, immunocytochemistry, and a TaqMan Scorecard Assay. Mutations in TRNT1 caused reduced levels of full-length TRNT1 protein and expression of a truncated smaller protein in both patient-specific iPSCs and iPSC-derived retinal organoids. Patient-specific iPSCs and iPSC-derived retinal organoids exhibited a deficit in autophagy, as evidenced by aberrant accumulation of LC3-II and elevated levels of oxidative stress. Autologous stem cell-based disease modeling will provide a platform for testing multiple avenues of treatment in patients suffering from TRNT1-associated RP.
视网膜色素变性（RP）是一组异质性单基因疾病，其特征是外神经视网膜的光感受光感受器细胞进行性死亡。我们最近在tRNA核苷酸转移酶、CCA添加1（TRNT1）基因中发现了新的低表达突变，这些突变会导致早发性RP。为了在体外模拟这种疾病，我们从分子确诊的TRNT1相关RP患者的皮肤成纤维细胞中生成了患者特异性诱导多能干细胞（iPSC）和iPSC来源的视网膜类器官。使用逆转录聚合酶链反应（rt-PCR）、免疫细胞化学和TaqMan计分卡检测法确认了多能性。TRNT1突变导致患者特异性iPSC和iPSC来源的视网膜类器官中全长TRNT1蛋白水平降低，并表达一种截短的较小蛋白。患者特异性iPSC和iPSC来源的视网膜类器官表现出自噬缺陷，这可通过LC3-II的异常积累和氧化应激水平升高得到证明。基于自体干细胞的疾病建模将为测试TRNT1相关RP患者的多种治疗途径提供一个平台。
