cGAS-STING Pathway Mediates Retinal Pigmental Epithelial Dysfunction in Diabetic Retinopathy

Area of Science:

• Ophthalmology
• Immunology
• Cell Biology

Background:

• Diabetic retinopathy (DR) is a leading cause of vision loss, with current treatments being ineffective for some patients.
• The retinal pigment epithelium (RPE) is crucial for neural retina protection and its dysfunction is implicated in DR.
• Mitochondrial damage and associated pathways are increasingly recognized as contributors to DR pathogenesis.

Purpose of the Study:

• To investigate the role of double-stranded DNA (dsDNA) and the cyclic GMP-AMP synthase (cGAS)-STING pathway in DR.
• To determine if mitochondrial damage in RPE cells triggers cGAS-STING pathway activation.
• To evaluate the therapeutic potential of STING inhibition in DR.

Main Methods:

• Quantified dsDNA levels in aqueous humor of DR patients and controls.
• Utilized fundus autofluorescence to assess RPE dysfunction.
• Employed in vivo and in vitro DR models to study RPE cells, mitochondrial damage, and cGAS-STING pathway activation.
• Administered pharmacological STING inhibitors in vitro and in vivo.

Main Results:

• DR patients exhibited elevated aqueous humor dsDNA levels and signs of early RPE dysfunction.
• DR models showed mitochondrial damage, dsDNA leakage in RPE, and retinal cGAS-STING pathway activation.
• STING inhibition reduced dsDNA accumulation, improved mitochondrial health, and decreased inflammation in vitro.
• In vivo STING inhibition ameliorated RPE dysfunction and retinal vascular abnormalities.

Conclusions:

• The cGAS-STING pathway plays a significant role in the pathogenesis of diabetic retinopathy.
• Mitochondrial dysfunction in RPE cells activates the cGAS-STING pathway, driving RPE disruption and vascular instability.
• Inhibiting the STING pathway presents a promising therapeutic strategy for managing DR and preventing vision loss.