­­STAT3 combines with Rho-ROCK signaling pathway inhibitor, regulate axon growth of ganglion cells derived from retinal Müller cells

Abstract

BackgroundMüller differentiated RGCs have potential therapeutic value for glaucoma. However, axonal regeneration of differentiated RGCs has been a difficult problem. Studies have confirmed that STAT3 and Y27632 play essential roles in regulating neuronal axon regeneration. Whether STAT3 and Y27632 can induce the Müller differentiated RGCs axon regeneration is still unknown.MethodRetina Müller cells were isolated and purified from Day 21 SD rats’ retina and were differentiated into retinal stem cells. The stem cells were randomly divided into five groups (control group, AAV-STAT3 group, shSTAT3 group, Y27632 group and AAV-STAT3 + Y27632 group). The axon length in each group were measured by ImageJ. Immunofluorescence were used to label the RGCs. The mRNA level of pluripotent associated and differentiation-associated proteins was analysed by qRT-PCR. Stem cells in different groups were injected into mice model of glaucoma. Immunohistochemical, Immunohistochemistry and OCT were performed to access RGC layer thickness in glaucoma model. VEP was used to detect the optic nerve conduction function.ResultsIn this study, we found that overexpression of STAT3 could promote the growth of RGCs axons generated by Müller cell differentiation. Combined with Y27632, axonal regeneration was significantly longer than that of the STAT3 group. However, after STAT3 was knocked out, axonal regeneration significantly decreased or even stopped. The mRNA levels of Esrrb, Prdm14, Sox2, and Rex1 in Müller differentiated RGCs after overexpression STAT3 combined with Y27632 were significantly increased, while the mRNA levels of Nestin, Eomes, Mixl1 and Gata4 were significantly decreased. The mRNA levels of Socs3, Pten, Klf9, and Mdm4 were significantly decreased, while the mRNA levels of Dclk2, Armcx1, C-MYC, and Nrn1 were significantly increased. The mRNA levels of differentiation and pluripotency marker genes showed opposite results after STAT3 deletion. After injecting Müller differentiated RGCs intervened by STAT3 combined with Y27632 into the eyes of the glaucoma model mice, the axon length, OCT displayed RGC layer thickness and the electrophysiology indicated by VEP were superior to those of the glaucoma model group.ConclusionsThese findings suggested that STAT3 combined with Y27632 can significantly improve the axonal growth level of RGCs, and reveal the potential mechanism to induce pluripotency of RGCs.