Abstract
Purpose :
cGAS-STING pathway is a key cytosolic DNA sensor signaling in innate immunity. Activation of cGAS-STING has been previously detected in retinal pigment epithelium (RPE) of Geographic atrophy (GA) patients, potentially contributes to pathogenesis of AMD (1). We have recently shown that cGAS and STING are dose-dependently upregulated in RPE and retina of an experimental GA-like mouse model (2). In the current study, we are aimed to identify drugs that can inhibits cGAS-STING signaling and prevents oxidative stress-induced RPE and retina injury.
Methods :
X-ray irradiation (8 GY) was used to induce cytosolic DNA leakage in ARPE-19 cells. Immunofluorescence-based high-content analysis was used to screen an epigenetic library which contains 288 FDA-approved small molecules. Western blot and RT-PCR analysis confirmed the inhibitory effects of the identified molecules on cGAS and STING expression in ARPE and photoreceptor cell line 661W. Fundus photography, RPE flat mount and immunohistochemistry analysis determined the effects of the identified molecule on sodium iodate (SI) (35mg/kg)-induced RPE and retina degeneration.
Results :
X-ray irradiation lead to obvious DNA damage and accumulation of cytosolic DNA. Drug screening identified BET inhibitor JQ1 exerts significant suppressive effect on cytosolic DNA release (P <0.05). The RNA and proteins level of cGAS and STING were upregulated after irradiation or H2O2 treatment, whereas JQ1 treatment significantly represses such upregulation as well as the expression of downstream NFκB signaling (P <0.01). Application of JQ1 (50mg/kg) after SI injection alleviates oxidative stress-induced RPE and retina inflammation and degeneration.
Conclusions :
Together, we identified that JQ1 suppresses cGAS and STING expression in cells and in mouse retina and RPE upon oxidative stress. This study may provide new treatment strategy for GA.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.