Oculocutaneous albinism (OCA) is characterized by reduced melanin biosynthesis affecting the retina, thus impairing visual function. The disease pathology of OCA is poorly understood at the cellular level due to unavailability of suitable biological model systems. This study aimed to develop a disease-specific in vitro model for OCA type 1A, the most severe form caused by TYR (tyrosinase) gene mutations, using retinal pigment epithelium (RPE) differentiated from patient-derived human-induced pluripotent stem cells (hiPSCs). A comparative study between healthy and OCA1A RPE cells revealed that while healthy RPE cells exhibited timely onest of pigmentation during differentiation, OCA1A RPE cells failed to pigment even after an extended culture period. This observation was validated by ultrastructural studies using electron microscopy, hinting at melanosome-specific defects. Immunocytochemistry demonstrated abnormal expression patterns of melanogenesis-specific protein markers in OCA1A RPE cells, indicating reduced or absence of melanin synthesis. Next, a quantitative assay was performed to confirm the absence of melanin production in OCA1A RPE cells. Tyrosinase assay showed no activity in OCA1A compared with healthy RPE, suggesting non-functionality of TYR, further corroborated by western blot analysis showing complete absence of the protein. Gene expression by RNA sequencing of healthy and OCA1A RPE cells uncovered differential gene expression associated with lens development, visual perception, transmembrane transporter activity, and key signaling pathways. This disease-in-a-dish model of OCA1A provides an excellent platform to understand disease mechanism, identify potential therapeutic targets, and facilitate gene therapy or gene correction.

眼皮肤白化病 (OCA) 的特点是影响视网膜的黑色素生物合成减少，从而损害视觉功能。由于缺乏合适的生物模型系统，OCA 的疾病病理学在细胞水平上知之甚少。本研究旨在利用从患者来源的人诱导多能干细胞 (hiPSC) 分化而来的视网膜色素上皮 (RPE)，开发针对 1A 型 OCA（由TYR （酪氨酸酶）基因突变引起的最严重形式）的疾病特异性体外模型。 ）。健康和 OCA1A RPE 细胞之间的比较研究表明，虽然健康 RPE 细胞在分化过程中及时表现出色素沉着，但 OCA1A RPE 细胞即使在延长培养期后也无法色素沉着。这一观察结果通过电子显微镜的超微结构研究得到了验证，暗示了黑素体特异性的缺陷。免疫细胞化学显示 OCA1A RPE 细胞中黑色素生成特异性蛋白标记物的异常表达模式，表明黑色素合成减少或缺乏。接下来，进行定量测定以确认 OCA1A RPE 细胞不产生黑色素。与健康的 RPE 相比，酪氨酸酶测定显示 OCA1A 没有活性，表明TYR没有功能，蛋白质印迹分析进一步证实了该蛋白完全不存在。通过对健康和 OCA1A RPE 细胞进行 RNA 测序进行基因表达发现，与晶状体发育、视觉感知、跨膜转运蛋白活性和关键信号通路相关的差异基因表达。这种 OCA1A 的“培养皿中的疾病”模型为了解疾病机制、识别潜在的治疗靶点以及促进基因治疗或基因校正提供了一个极好的平台。