Abstract
Purpose :
Neovascular or wet age-related macular degeneration (nAMD) is a major cause of irreversible vision loss and impairment worldwide. While anti-VEGF therapies have shown great success in the clinic, some patients do not respond to conventional treatment. Gliosis plays key roles in many ocular diseases, but its role in the formation of choroidal neovascularization (CNV) remains poorly understood. We aim to investigate the role of glial c-Fos, a proto-oncogene, in the development of pathological CNV.
Methods :
The Cre/LoxP system was used to generate inducible glial specific c-Fos knockout mice (c-Fos cKO) by crossing c-Fos flox/flox mice with GlastCreER mice (JAX# 012586). The laser induced CNV mouse model was used as a preclinical model of nAMD. Tamoxifen was administered intraperitoneally to induce Cre driven recombination. An image-guided laser system (Micron IV, Phoenix) was used to generate laser-induced CNV. Image-guided optical coherence tomography (Micron IV, Phoenix) was performed to confirm rupture of Buch’s membrane for successful laser photocoagulation. Eyes were enucleated, fixed, and stained with endothelial cell marker isolectin B4. The retinal pigment epithelium-sclera-choroid complex was dissected and flat mounted for phenotypical analysis. Cryosections of the retina were collected to visualize c-Fos localization. CNV lesion size was quantified using Image J, and all statistical analyses were performed with GraphPad Prism (v8.0).
Results :
In the laser induced CNV mouse model, c-Fos expression was highly induced post-laser in the inner nuclear layer of the retina, where the cell bodies of Müller glia reside. Glial c-Fos knockout mice were successfully generated, and knockout efficacy and glial specificity were validated using immunohistochemistry. Glial c-Fos deficiency markedly reduced glial activation labeled by glial fibrillary acidic protein immunofluorescence. c-Fos cKO mice exhibited significantly smaller CNV lesion sizes (n=8, p<0.01) compared to floxed littermate controls.
Conclusions :
Our data suggests that glial c-Fos mediates pathological neovascularization in the laser induced CNV mouse model. Targeting glial c-Fos signaling may be a potential therapeutic for treating aberrant choroidal angiogenesis.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.