RNA-Seq Analysis of Neuronal Gene Expression Changes in Rat Müller Glia-Derived rMC-1 Cells Under Treatment with Compounds Promoting Photoreceptor Differentiation

Background: The principal glial cells of the retina, Müller glia, play a central role in retinal regeneration in teleost fish and have recently attracted attention as potential sources of neuronal regeneration in mammals. Objectives: In this study, we examined whether SV40-immortalized rat Müller glia could be directed toward neuronal differentiation using a non-genetic approach with defined culture conditions. Methods: Comprehensive transcriptomic profiling by RNA sequencing indicated that changes in culture medium alone could induce transcriptional reprogramming toward a neuronal lineage. Results: Specifically, expression of Müller glia-related genes decreased, while a subset of photoreceptor-related transcription factors and specific genes showed altered expression, suggesting early-stage induction toward a photoreceptor-like fate. This finding suggests that even immortalized cells may exhibit activation of neuronal genes through non-genetic culture interventions. Gene set enrichment analysis further revealed upregulation of pathways related to the synaptic vesicle cycle, metabolic activation, oxidative stress defense, and lysosomal function, consistent with initiation of neuronal differentiation. Conversely, pathways associated with cell cycle regulation and stemness signaling were downregulated, reflecting a transition from a proliferative to a differentiation-prone state. Collectively, these results provide preliminary molecular markers for early neuronal induction and potential targets for chemical screening. Conclusions: Importantly, this strategy enables neuronal-like differentiation of Müller glia without genetic manipulation, offering a safe and cost-effective platform. Overall, our findings may support the development of in vitro models for retinal neuroregeneration and facilitate research toward regenerative therapies for retinal disorders.