Atoh7 promotes the differentiation of retinal stem cells derived from Muller cells into retinal ganglion cells by inhibiting Notch signaling

Introduction: Retinal Muller cells exhibit the characteristics of retinal progenitor cells, and differentiate into ganglion cells under certain conditions. However, the number of ganglion cells differentiated from retinal Muller cells falls far short of therapeutic needs. This study aimed to develop a novel protocol to promote the differentiation of retinal Muller cells into ganglion cells and explore the underlying signaling mechanisms. Methods: Muller cells were isolated and purified from rat retina and induced to dedifferentiate into retinal stem cells. Next the stem cells were transfected with lentivirus PGC-FU-GFP or lentivirus PGC-FU-Atoh7-GFP. In addition, the stem cells were transfected with Brn-3b siRNA or Isl-1 siRNA or treated with Notch inhibitor gamma-secretase inhibitor (GSI). Results: The proportion of ganglion cells differentiated from Atoh7-tranfected stem cells was significantly higher than that of controls. Knockdown of Brn-3b or Isl-1 inhibited, while GSI promoted, the differentiation into retinal ganglion cells. Atoh7 promoted the expression of Brn-3b and Isl-1 but inhibited the expression of Notch1. Conclusions: Atoh7 promotes the differentiation of Muller cells-derived retinal stem cells into retinal ganglion cells by inhibiting Notch signaling, thus opening up a new avenue for gene therapy and optic nerve regeneration in glaucoma.