光感受器细胞移植是目前晚期视网膜退行性疾病治疗的重要研究方向。然而，如何获得大量可供移植的人源视锥细胞成为目前的技术瓶颈之一，其主要原因在于：视锥细胞命运选择的分子机制尚不清楚阻碍了干细胞定向分化的策略制定。在前期研究中，我们运用单细胞转录谱测序技术对人胚胎干细胞来源的3D视网膜中视锥细胞分化轨迹进行了重建，并在差异基因中首次发现TGF-β通路在视锥细胞命运选择和成熟中的时序性变化过程。由此我们提出了“TGF-β负向调控因子BAMBI促进视锥细胞的命运选择；此后在视锥细胞的成熟过程中TGF-β通路起到正向调控的作用”的科学假说。本申请将在前期研究的基础上进一步完善对光感受器细胞谱系发育的研究，探讨BAMBI以及TGF-β通路对视锥细胞命运选择和成熟的影响及下游调控机制，基于调控TGF-β通路制定及优化视锥细胞定向分化方案，为光感受器细胞移植的临床转化和应用奠定基础。

Photoreceptor transplantation is of the most important research topics in the treatment of late-stage retinal degenerative disease. However, how to obtain the clinical-grade amount of human cone photoreceptors remains to be one of the technical obstacles. It is largely attributed to the unknown molecular mechanism of cone development which hampers the study of stem cell differentiation to cone. In our study, we have deconstructed the roadmap of human embryonic stem cell (hESC)-derived cone differentiation in a single-cell resolution. In the previous result, we found for the first time the stage-specific regulation of TGF-β signaling in the fate bifurcation and maturation of cone. Accordingly, the hypothesis is proposed: TGF-β negative regulator BAMBI promotes the fate decision of cone from photoreceptor precursor, while the enhancement of TGF-β signaling facilitates the maturation of cone in the later stage. Based on the single-cell RNA sequencing, we will further study the lineage specification of photoreceptor. The effect and downstream mechanism of BAMBI and TGF-β signaling in the fate bias and maturation of cone will be investigated. The strategical establishment of hESC-derived cone differentiation according to the manipulation of TGF-β signaling will provide the foundation for the clinical application of photoreceptor replacement therapy.