Technische Universität Dresden, Center for Molecular and Cellular Bioengineering (CMCB), Center for Regenerative Therapies Dresden (CRTD), Fetscherstraße 105, 01307 Dresden, Germany.
Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany.
Stem Cell Reports. 2020 Dec 8;15(6):1347-1361. doi: 10.1016/j.stemcr.2020.10.013. Epub 2020 Nov 25.
Phagocytosis is a key function in various cells throughout the body. A deficiency in photoreceptor outer segment (POS) phagocytosis by the retinal pigment epithelium (RPE) causes vision loss in inherited retinal diseases and possibly age-related macular degeneration. To date, there are no effective therapies available aiming at recovering the lost phagocytosis function. Here, we developed a high-throughput screening assay based on RPE derived from human embryonic stem cells (hRPE) to reveal enhancers of POS phagocytosis. One of the hits, ramoplanin (RM), reproducibly enhanced POS phagocytosis and ensheathment in hRPE, and enhanced the expression of proteins known to regulate membrane dynamics and ensheathment in other cell systems. Additionally, RM rescued POS internalization defect in Mer receptor tyrosine kinase (MERTK) mutant hRPE, derived from retinitis pigmentosa patient induced pluripotent stem cells. Our platform, including a primary phenotypic screening phagocytosis assay together with orthogonal assays, establishes a basis for RPE-based therapy discovery aiming at a broad patient spectrum.
吞噬作用是全身各种细胞的关键功能。视网膜色素上皮（RPE）对光感受器外节（POS）的吞噬作用缺陷会导致遗传性视网膜疾病和可能的年龄相关性黄斑变性导致视力丧失。迄今为止，尚无有效的治疗方法可恢复丧失的吞噬功能。在这里，我们开发了一种基于人胚胎干细胞（hRPE）的 RPE 衍生的高通量筛选测定法，以揭示增强 POS 吞噬作用的增强子。其中一种命中药物是 ramoplanin（RM），它可重复地增强 hRPE 中的 POS 吞噬作用和包裹作用，并增强其他细胞系统中已知调节膜动力学和包裹作用的蛋白质的表达。此外，RM 可挽救源自色素性视网膜炎患者诱导多能干细胞的 Mer 受体酪氨酸激酶（MERTK）突变 hRPE 的 POS 内化缺陷。我们的平台包括一个基于原发性表型筛选吞噬作用测定法和正交测定法的平台，为针对广泛患者群体的基于 RPE 的治疗发现奠定了基础。
