Data_Sheet_1_Mutant PRPF8 Causes Widespread Splicing Changes in Spliceosome Components in Retinitis Pigmentosa Patient iPSC-Derived RPE Cells.zip

Retinitis pigmentosa (RP) is a rare, progressive disease that affects photoreceptors and retinal pigment epithelial (RPE) cells with blindness as a final outcome. Despite high medical and social impact, there is currently no therapeutic options to slow down the progression of or cure the disease. The development of effective therapies was largely hindered by high genetic heterogeneity, inaccessible disease tissue, and unfaithful model organisms. The fact that components of ubiquitously expressed splicing factors lead to the retina-specific disease is an additional intriguing question. Herein, we sought to correlate the retinal cell-type-specific disease phenotype with the splicing profile shown by a patient with autosomal recessive RP, caused by a mutation in pre-mRNA splicing factor 8 (PRPF8). In order to get insight into the role of PRPF8 in homeostasis and disease, we capitalize on the ability to generate patient-specific RPE cells and reveal differentially expressed genes unique to RPE cells. We found that spliceosomal complex and ribosomal functions are crucial in determining cell-type specificity through differential expression and alternative splicing (AS) and that PRPF8 mutation causes global changes in splice site selection and exon inclusion that particularly affect genes involved in these cellular functions. This finding corroborates the hypothesis that retinal tissue identity is conferred by a specific splicing program and identifies retinal AS events as a framework toward the design of novel therapeutic opportunities.

色素性视网膜炎（Retinitis pigmentosa, RP）是一种罕见的进行性疾病，可累及光感受器细胞（photoreceptors）与视网膜色素上皮（retinal pigment epithelial, RPE）细胞，最终以失明作为转归。尽管该疾病对医疗与社会造成了极高的影响，但目前尚无能够延缓疾病进展或治愈该病的治疗方案。有效疗法的开发长期受限于三大瓶颈：极高的遗传异质性、难以获取的病变组织，以及无法忠实模拟人类疾病的模式生物。此外，广泛表达的剪接因子组分却引发视网膜特异性疾病这一现象，更是一个引人深思的科学问题。本研究旨在将视网膜细胞类型特异性疾病表型，与一例由前mRNA剪接因子8（pre-mRNA splicing factor 8, PRPF8）突变引发的常染色体隐性RP患者的剪接谱进行关联分析。为深入解析PRPF8在细胞稳态与疾病发生中的作用，我们借助诱导患者特异性RPE细胞的技术手段，鉴定出RPE细胞特有的差异表达基因。研究发现，剪接体复合物与核糖体功能通过差异表达及可变剪接（alternative splicing, AS）决定细胞类型特异性，而PRPF8突变会引发剪接位点选择与外显子保留的全局改变，尤其会影响上述两类细胞功能相关的基因。本研究结果佐证了视网膜组织特性由特定剪接程序赋予这一假说，并将视网膜AS事件作为开发新型治疗策略的潜在框架。