Abstract
Purpose :
Retinal ganglion cells (RGCs) are the sole projection neurons in the retina that are responsible for conveying visual electrophysiological signals generated by upstream retinal neural circuits to the visual center of the brain. Shootin1 is an actin filament activity regulatory protein that has been shown to play key roles in regulating neurite development and the migration of brain neurons. Our Immunofluorescence (IF) staining results showed that Shootin1 is specifically expressed in developing RGCs in the retina. However, the roles of Shootin1 in RGCs remain unknown. The purpose of this study was to investigate the function of Shootin1 in RGCs.
Methods :
IF was used to examine the expression patterns of Shootin1 during retinal development and in induced RGCs (iRGCs). CDSs or shRNAs were introduced into cultured cells via lentiviruses. IRGCs were induced from mouse embryonic fibroblasts by overexpressing Ascl1, Brn3b, and Islet1. ShRNAs were used to knock down Shootin1. IF was used to examine cell fate and neurite development. RNA-Seq was used to examine transcriptome changes.
Results :
Shootin1 exhibited a dynamic but specific expression pattern in developing RGCs in vivo and in iRGCs in vitro. Knockdown of Shootin1 impeded axonal development and decreased the reprogramming efficiency of iRGCs. Conversely, overexpressing Shootin1 promoted the neurite complexity of iRGCs. RNA-Seq analysis revealed significant changes in the transcriptome when Shootin1 was knocked down during iRGC reprogramming.
Conclusions :
Shootin1 is specifically expressed in developing RGCs in the retina. Using the iRGC as a model, we demonstrated that Shootin1 plays key roles in regulating RGC dendrite and axon development, possibly through regulating both actin dynamics and gene expression. This study helps to elucidate the molecular mechanisms governing RGC neurite development and may aid in etiology and therapeutic studies aimed at treating RGC-related diseases, such as glaucoma.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.