Chemical Reprogramming of Fibroblasts into Functional Retinal Pigment Epithelium Cells

Restoring retinal pigment epithelium (RPE) cells is crucial for treating retinal degenerative (RD) diseases, with chemical reprogramming offering a transformative, scalable solution. However, identifying key compounds for generating functional RPE cells remains challenging. Here, we present a two-step chemical reprogramming strategy to convert fibroblasts into functional RPE (ciRPE) cells. Leveraging the Single-Cell Reprogramming Compound Finder (scRCF), which integrates transcriptomics-guided predictions with advanced screening, we identified compound cocktails that precisely and efficiently reprogram fibroblasts through an intermediate state into ciRPE cells. These ciRPE cells closely mimic the structure and function of native RPE cells, and upon transplantation into RD rats, they seamlessly integrate into host tissue, protect photoreceptors, and restore visual function. Omics and mechanistic analyses revealed that the identified compounds synergistically activate core transcription factors, including Ascl1 and Olig2, orchestrating the reprogramming process. This work provides a scalable platform for RPE cell generation, advancing cell replacement therapies for RD diseases.