Abstract
Purpose :
Pathological proliferative angiogenesis causes irreversible blindness in vascular eye diseases such as retinopathy of prematurity (ROP). Inflammatory mediators are known key regulators in retinopathy and inflammation is often thought to come from infiltrating inflammatory cells, but we recently found that photoreceptors also can signal for blood vessel growth through inflammatory signals via c-Fos in a mouse model of retinal angiogenesis. However, the underlying molecular and cellular mechanisms of photoreceptor control in ROP via c-Fos remain to be determined.
Methods :
Photoreceptor specific c-Fos knockout mice (c-Fos cKO) wss generated by crossing c-Fos flox/flox mice with rod photoreceptor specific Rhodopsin improved Cre mice (Rho-iCre). The oxygen induced retinopathy (OIR) mouse model was generated as a ROP preclinical mouse model. RNA Isolation, real-time PCR, western blot and immunohistochemistry were used to analyze gene expression and protein localization. Confocal imaging, fundus fluorescein angiography and HE staining were used to identify phenotypes. Adeno associated virus (AAV) was used to modulate gene expression. CUT&Tag sequencing was used to examine the targets of c-Fos. GraphPad Prism (v8.0) was used for statistical analysis.
Results :
c-Fos expression was significantly induced and robustly activated in OIR retinas including photoreceptor layer at postnatal (P) 13. c-Fos deficiency in rod photoreceptors significantly reduced NV by 30% (p=0.007, n=16-26) without influencing VO (p=0.33) compared to littermate floxed controls. Pharmacologic treatment with c-Fos (AP-1) inhibitor (SR11302) and photoreceptor specific AAV shRNA subretinal delivery targeting c-Fos significantly suppressed retinal neovascularization in OIR model. CUT&Tag sequencing data showed that over 200 genes potentially bind to c-Fos at P14 only in retina with OIR not in normal control. In contrast, there were over 150 genes potentially bind to c-Fos at P14 only under normal condition but not in OIR condition.
Conclusions :
These data suggest that c-Fos in photoreceptors mediates neovascularization through modulating photoreceptor-released inflammatory proteins in OIR retinas. Targeting c-Fos protected against neovascularization and may be a potential therapeutic for treating retinal angiogenesis.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.