Abstract
Purpose :
cGAS-STING is a cytosolic DNA-sensing innate immunity pathway. Ours and other studies recently revealed that cGAS-STING contribute to retinal degeneration and age-related macular degeneration [1, 2]. Here, we aimed to investigate the activity of cGAS-STING in response to light damage (LD), and the retinal cell type(s) expressing cGAS-STING components.
Methods :
To induce LD, BALB/c mice (6-8 weeks, male) were exposed to 15000 lux white light for 2 h. Hematoxylin and eosin staining and immunofluorescence access retinal morphology and distribution of macrophages/microglia. RNA-sequencing (RNA-seq) determines gene transcription. Single cell RNA-seq analysis of published database [3] determines the expression of cGAS-STING components in retinal cells. Western blot assay measures retinal protein expression.
Results :
LD activated inflammatory responses, the top upregulated pathways include immune effector process, leukocyte activation and migration, cytokine signaling and innate immune response. Genes enriched in cytosolic DNA sensing and the type I interferon pathway were significantly upregulated. Sc RNA-seq demonstrated that STING, IRF3 and TBK1 were enriched in retinal microglia. In control retinas, STING-positive cells were mainly localized in the ganglion cell layer. After LD, there was an obvious increase in the STING signal in the retina. Remarkably, most microglia/macrophages infiltrating the photoreceptor layer showed positive STING staining.
Conclusions :
LD induces cGAS-STING signaling in mouse retina. Active microglia/macrophages showed increased STING expression after LD.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.