Double-Stranded RNA Induces Retinal Pigment Epithelium Cell Degeneration and Inflammation.

Area of Science:

• Ophthalmology
• Immunology
• Molecular Biology

Background:

• Retinal pigment epithelium (RPE) inflammation is linked to age-related macular degeneration (AMD).
• RIG-I signaling, initiated by double-stranded RNA (dsRNA), drives type I interferon responses.
• dsRNA accumulation is observed in AMD tissues, particularly at the geographic atrophy (GA) stage.

Purpose of the Study:

• To investigate the role of RIG-I signaling in RPE inflammation in response to dsRNA.
• To determine if dsRNA accumulation is a driver of AMD pathogenesis.
• To establish a murine model for studying dsRNA-induced RPE and photoreceptor degeneration.

Main Methods:

• shRNA knockdown to assess RIG-I's role in interferon response in iPS-RPE cells.
• Analysis of human AMD tissues for dsRNA accumulation.
• Subretinal challenge of a murine model with synthetic dsRNA (3p-hpRNA).

Main Results:

• RIG-I is crucial for initiating interferon responses to both synthetic dsRNA and Alu elements in iPS-RPE.
• Human AMD tissues show increased dsRNA, correlating with GA stage.
• Murine model confirmed dsRNA accumulation triggers type I interferon response, RPE degeneration, and photoreceptor loss.
• Synthetic dsRNA induced acute RPE response and significant leukocyte migration.

Conclusions:

• RIG-I signaling is vital for regulating subretinal inflammation.
• dsRNA accumulation is implicated as a key factor in the pathogenesis of AMD.
• The developed murine model effectively replicates key aspects of AMD pathology.