RETINAL EXPRESSION OF THE NF-KB INHIBITORY GENE M013 DECREASES THE RATE OF RETINAL DEGENERATION OF A GEOGRAPHIC ATROPHY MOUSE MODEL

Abstract

Purpose : Age-related macular degeneration (AMD) has been linked to inflammation and oxidative stress. We have previously demonstrated that retinal inhibition of caspase-1 with via AAV gene delivery can slow down retinal degeneration in a mouse model of geographic atrophy. This protection occurs at later stage of the mouse model. The M013 myxoma gene is known to inhibit ASC dependent activation of caspase-1 and the NF-kB nuclear translocation. Therefore, M013 not only blocks the activation of IL-1β and IL-18, but can also repress the transcription of multiple inflammatory genes. Here we provide evidence that retinal expression of the modified TatM013 can protect the retina of a geographic atrophy mouse model during early stages.

Methods : Mice of the Sod2^floxed:VMD2^Cre+ genotype were injected intravitreally with 10¹⁰ vector genome copies of AAV2quad(Y-F)+T491V vector delivering either sGFP or sGFP-TatM013v5 at 8 weeks of age. Mice were evaluated at 3, 6, and 9 months of age by spectral domain optical coherence tomography (SD-OCT) and electroretinography (ERG). Gliosis was detected by GFAP and Iba-1 immunofluorescence (IF). Cytokine and chemokine changes in the retina protein lysates was determined by multiplex ELISA. Changes in mRNA levels in the retina were quantified by RT-qPCR.

Results : Retinas treated with sGFP-TatM013 vector had statistically significantly higher a-, b-, and c-wave amplitudes when compared to sGFP treated eyes at the 3 and 6-months evaluations. SD-OCT evaluation demonstrated a protection of the outer segments in the sGFP-TatM013 when compared to sGFP treated eyes. Retinas expressing sGFP-TatM013 showed less GFAP and Iba-1 staining when compared to sGFP at 6 months of age. RT-qPCR studies demonstrated a significant decrease in multiple genes associated with M1 and M2 macrophages/microglia cells at 9 months of age. Finally, cytokines and chemokines were significantly altered including the neuroprotective leukemia inhibitory factor (LIF).

Conclusions : Retinal gene expression of TatM013 transiently protected the retina function of a mouse model of geographic atrophy. Treatment with TatM013 decreased gliosis, decreased the expression of inflammatory genes, and a transient increase in retinal LIF expression. Our studies suggest that targeting the NF-kB signaling locally within the retina could provide protection against AMD during early stages.

This is a 2020 ARVO Annual Meeting abstract.