Immunosuppressant-free photosensitivity rescue of mnu-injured mice using human photoreceptor-like cells induced by rapid chemical reprogramming of fibroblasts as an intermediate stage

Abstract

Recent studies have revealed that photoreceptor-like cells derived from human induced pluripotent stem-cells (hiPSCs) were a potential approach for reversing lost vision. To make the hiPSC application in a clinical setting more accessible and efficient, we have developed a two-step method to differentiate an adequate number of chemically-induced photoreceptor-like cells (CiPCs) cells from hiPSCs in a shorter period (three weeks) through chemical reprogramming. The CiPCs were verified through cell morphology and flow cytometry methods for the expression of photoreceptor markers. The electrical signal detection of calcium, potassium, and sodium channels was performed with an in vitro model to determine the function of CiPCs. ERG recording was utilized for the in vivo evaluation. Photoreceptor markers, including recoverin and rhodopsin, were expressed in the CiPCs. Calcium, potassium, and sodium signals were detected in CiPCs. Clear ERG responses were observed in the retina of four out of six CiPCs transplanted mice (MNU-injured model), while none was observed in the control group. Moreover, classic symptoms of immune rejection were unobserved in the eyes of mice. Consequently, our hiPSC-derived photoreceptor-like cells successfully restored photosensitivity in photoreceptor-degenerated mice, indicating a potential clinical application for etiologically treating retinal degenerative diseases and restoring lost vision with less, or even no need for immunosuppressants.