miRNA Changes in Retinal Ganglion Cells after Optic Nerve Crush and Glaucomatous Damage

The purpose of this study was to characterize the miRNA profile of purified retinal ganglion cells (RGC) from healthy and diseased rat retina. Diseased retina includes those after a traumatic optic nerve crush (ONC), and after ocular hypertension/glaucoma. Rats were separated into four groups: healthy/intact, 7 days after laser-induced ocular hypertension, 2 days after traumatic ONC, and 7 days after ONC. RGC were purified from rat retina using microbeads conjugated to CD90.1/Thy1. RNA were sequenced using Next Generation Sequencing. Over 100 miRNA were identified that were significantly different in diseased retina compared to healthy retina. Considerable differences were seen in the miRNA expression of RGC 7 days after ONC, whereas after 2 days, few changes were seen. The miRNA profiles of RGC 7 days after ONC and 7 days after ocular hypertension were similar, but discrete miRNA differences were still seen. Candidate mRNA showing different levels of expression after retinal injury were manipulated in RGC cultures using mimics/AntagomiRs. Of the five candidate miRNA identified and subsequently tested for therapeutic efficacy, miR-194 inhibitor and miR-664-2 inhibitor elicited significant RGC neuroprotection, whereas miR-181a mimic and miR-181d-5p mimic elicited significant RGC neuritogenesis.