NMNAT2 Is Downregulated in Glaucomatous RGCs and RGC-Specific Gene Therapy with NMNAT2 Overexpression Rescues Glaucomatous Neurodegeneration and Visual Function

ABSTRACT: The lack of neuroprotective treatments for retinal ganglion cells (RGCs) and optic nerve (ON) is a central challenge for glaucoma management. Emerging evidence suggests that redox factor NAD+ decline is a hallmark of aging and neurodegenerative diseases including glaucoma. Supplementation with NAD+ precursors and overexpression of the nicotinamide mononucleotide adenylyltransferase (NMNAT), the key enzyme involved in the NAD+ biosynthetic process, have significant neuroprotection effect on glaucoma. Among the three NMNAT isoforms, only NMNAT2 is enriched in neurons, especially in axons, however, its role in glaucoma is not well studied. Here we present the expression levels of the enzymes that involved in NAD+ metabolism in both naïve and glaucomatous mouse RGCs. Intriguingly, NMNAT2 is the dominant form of NMNATs in RGCs and only its mRNA level, but not NMNAT1 or NMNAT3, is significant decreased in glaucomatous RGCs. We then demonstrated proof-of-principal gene therapy strategy of restoring RGC-specific NMNAT2 and NAD+ levels by AAV2-mediated RGC-specific promoter mSncg-driven long half-life NMNAT2 mutant. This gene therapy strategy is further tested in two optic neuropathy models, traumatic ON crush model and ocular hypertension glaucoma model. RGC-specific NMNAT2 overexpression significantly promotes RGC somata and axons survival and preserves visual function in both models. Our studies suggest that the weaking of NMNAT2 expression in glaucomatous RGCs contributes to detrimental NAD+ decline and that modulating RGC intrinsic NMNAT2 level by AAV2-mSncg vector is a potent gene therapy for glaucomatous neuroprotection.

ORGANISM(S): Mus musculus

PROVIDER: GSE182483 | GEO | 2021/08/22

REPOSITORIES: GEO