Abstract
Purpose :
Inflammation and oxidative stress play an important role in retinal pigmented epithelium (RPE) degeneration in age-related macular degeneration. cGAS-driven innate immune response promotes inflammation through the activation of interferon-β (IFN-β) and interferon-stimulated genes (ISGs), activates DNA damage response (DDR) signaling, autophagy, and cellular senescence. Here, we hypothesized that cGAS plays a key role in mediating cellular responses to oxidative stress in the retina and RPE.
Methods :
All the experiments were carried out on 8-10 weeks old wild type (WT) and cGAS–/– C57BL/6J mice. To induce oxidative retinal damage, sodium iodate was injected intra-peritoneally (20mg/kg of body weight) into the experimental mice and PBS was injected in the control mice (n = 8 for each group). The RPE and retinal tissue were collected from the enucleated eyes. RNA was synthesized using RNeasy Mini Kit from Qiagen followed by cDNA synthesis with the help of QuantiTect Rev. Transcription Kit. Transcriptional changes were monitored by real-time PCR with SYBR green master mix on ABI QuantStudioTM 3 machine (Thermo Fisher Scientific, Inc., USA.
Results :
The inflammatory genes such as IFN-β, and ISG genes like Oas1A, Cxcl10, and Isg15 were found to be highly up-regulated in WT mice exposed to NaIO3 (vs. PBS), which were concomitantly reduced in cGAS–/– mice. Similarly, multiple DDR and senescence signature genes, Btg2, Fas, Rad9A, and Cdkn1a were induced by NaIO3 in a cGAS-dependent manner. Of note Ptgs2 (Cox2) was highly increased after NaIO3 treatment which drastically reduced in cGAS–/– mice compared to WT after NaIO3 treatment.
Conclusions :
Our study highlighted the involvement of the cGAS-STING pathway in inflammation and DDR during oxidative retinal damage induced by NaIO3 which further warrant a detailed mechanistic study.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.