Stimulation of c-Kit+ Retinal Progenitor Cells by Stem Cell Factor Confers Protection Against Retinal Degeneration
Abstract Background c-Kit/CD117, expressed in a series of tissue-specific progenitor cells, plays an important role in tissue regeneration and tissue homeostasis. We previously demonstrated that organoid-derived c-Kit+ retinal progenitor cells can facilitate the restoration of degenerated retina. Meanwhile, we have identified a population of endogenous c-Kit+ cells in retinas of adult mouse. However, the exact role of these cells in retinal degeneration remains unclear. Methods Retinal degeneration was induced by intravitreal injection of N-methyl-D-aspartate (NMDA). Two days post NMDA challenge, intravitreal injection of stem cell factor (SCF) was performed. Distribution and abundance of c-Kit+ cells and other retinal cells were evaluated by immunochemistry. Retinal function of treated mice was tested via flash electroretinogram (fERG) and the light/dark transition test. Possible regulatory pathways were evaluated by RNA sequencing. Results NMDA challenge increased the total number of c-Kit+ cells in the retinal ganglion cell layer (GCL), while slightly deregulated the protein level of SCF, which is mainly expressed in Müller cells. Both fERG and light/dark transition tests showed that intravitreal injection of SCF effectively improve the visual function of NMDA-treated mice. Consistently, the activation of microglia in injured retina has also been inhibited after SCF treatment. Mechanistically, SCF administration not only prevent the loss of retinal ganglion cells (RGCs), but also maintained the function of RGCs as quantified by fERG. Further, we performed transcriptome sequencing analysis of the retinal cells isolated from SCF-treated mice and the parallel control. Gene Ontology analysis showed that SCF-induced transcriptome changes were closely correlated with eye development-related pathways. Crystallins and several protective factors such as Pitx3 were significantly upregulated by SCF treatment. Conclusions Our results revealed the role of c-Kit+ cells in the protection of RGCs in NMDA-treated mice, via inhibiting the loss of RGCs. Administration of SCF can act as a potent strategy for treating retinal degeneration-related diseases.
