Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, 695 Charles Young Drive South, Los Angeles, CA 90095, USA.
Stem Cell Reports. 2019 Oct 8;13(4):747-760. doi: 10.1016/j.stemcr.2019.08.012. Epub 2019 Sep 19.
The development of the mammalian retina is a complicated process involving the generation of distinct types of neurons from retinal progenitor cells (RPCs) in a spatiotemporal-specific manner. The progression of RPCs during retinogenesis includes RPC proliferation, cell-fate commitment, and specific neuronal differentiation. In this study, by performing single-cell RNA sequencing of cells isolated from human embryonic stem cell (hESC)-derived 3D retinal organoids, we successfully deconstructed the temporal progression of RPCs during early human retinogenesis. We identified two distinctive subtypes of RPCs with unique molecular profiles, namely multipotent RPCs and neurogenic RPCs. We found that genes related to the Notch and Wnt signaling pathways, as well as chromatin remodeling, were dynamically regulated during RPC commitment. Interestingly, our analysis identified that CCND1, a G-phase cell-cycle regulator, was coexpressed with ASCL1 in a cell-cycle-independent manner. Temporally controlled overexpression of CCND1 in retinal organoids demonstrated a role for CCND1 in promoting early retinal neurogenesis. Together, our results revealed critical pathways and novel genes in early retinogenesis of humans.
哺乳动物视网膜的发育是一个复杂的过程，涉及到视网膜祖细胞（RPCs）以时空特异性的方式产生不同类型的神经元。在视网膜发生过程中，RPC 的进展包括 RPC 的增殖、细胞命运的决定和特定的神经元分化。在这项研究中，通过对源自人胚胎干细胞（hESC）的 3D 视网膜类器官的细胞进行单细胞 RNA 测序，我们成功地对人类早期视网膜发生过程中 RPC 的时间进展进行了重构。我们鉴定出两种具有独特分子特征的独特 RPC 亚型，即多能性 RPC 和神经发生性 RPC。我们发现，与 Notch 和 Wnt 信号通路以及染色质重塑相关的基因在 RPC 决定过程中是动态调节的。有趣的是，我们的分析表明，细胞周期 G1 期调控因子 CCND1 以细胞周期非依赖性的方式与 ASCL1 共表达。在视网膜类器官中，对 CCND1 进行时间控制的过表达显示 CCND1 在促进早期视网膜神经发生中的作用。总之，我们的研究结果揭示了人类早期视网膜发生中的关键途径和新基因。
