Neuronal gene expression and function in the growth-stimulated R28 retinal precursor cell line

Purpose. Proliferative retinal progenitor cells that express neuronal characteristics are potentially useful for developmental studies and as experimental graft material. The continuously-growing R28 retinal cell line has been distributed to over 60 laboratories for a variety of studies, yet has not been fully characterized. In this study, we tested the hypothesis that the proliferative R28 retinal cell line contains subpopulations of cells that express neuronal mRNAs and proteins characteristic of CNS neurons. Methods. To this end, we sought to determine the potential retinal, neuronal, and growth-related characteristics of this retinal cell line through gene expression profiling, coupled with confirmatory immunocytochemistry and electrophysiology. Results. Despite expression of growth-stimulatory oncogenes and growth-promoting factors, subpopulations of R28 cells express abundant retinal and neuronal markers, as well as the functional capacity to respond to specific neurotransmitters such as dopamine, acetylcholine, serotonin, and glycine. Conclusion. Proliferative R28 cells retain functional neuronal properties that may prove useful in future studies of neuronal differentiation and development.