Molecular Mechanisms Of Glaucoma

National Eye Institute

Investigators

Linked publications & trials

Abstract

Congruent to our study of the pathophysiology of glaucoma, we are also working on the development of its potential treatments. Retinal ganglion cell (RGC) loss is a hallmark of glaucoma and optic neuropathies. We previously demonstrated that intravitreal injection of human bone marrow-derived mesenchymal stem cells (BMSCs) or small extracellular vesicles secreted by BMSCs provided statistically significant RGC neuroprotection when compared to control samples. Our data also revealed that miRNAs play an important role in this observed RGC neuroprotection. We have continued the characterization of the miRNA profile of purified RGCs from healthy and diseased rat retina. Diseased retinas included 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. RGCs were purified from rat retina using microbeads conjugated to CD90.1/Thy1 and RNAs were sequenced using Next Generation Sequencing. Over 100 miRNAs were identified as significantly different between diseased retinas compared to healthy retinas. Considerable differences were seen in the miRNA expression of RGCs 7 days after ONC, whereas after 2 days, few changes were seen. The miRNA profiles of RGCs 7 days after ONC and 7 days after ocular hypertension were similar, but discrete miRNA differences were still seen. Candidate miRNAs showing different levels of expression after retinal injury were manipulated in RGC cultures using mimics/AntagomiRs. Of the five candidate miRNAs 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. Further testing of selected miRNAs in animal models and characterization of their targets in the retina are the next important steps in the search for new neuroprotective strategies. The US patent (US 11058729) describing exosomes and miRNAs as possible tools for glaucoma treatment was issued in 2021.