DDX58 variant triggers IFN‐β‐induced autophagy in trabecular meshwork and influences intraocular pressure

Abstract

Singleton–Merten syndrome (SMS) is a rare immunogenetic disorder affecting multiple systems, characterized by dental dysplasia, aortic calcification, glaucoma, skeletal abnormalities, and psoriasis. Glaucoma, a key feature of both classical and atypical SMS, remains poorly understood in terms of its molecular mechanism caused by DDX58 mutation. This study presented a novel DDX58 variant (c.1649A>C [p.Asp550Ala]) in a family with childhood glaucoma. Functional analysis showed that DDX58 variant caused an increase in IFN‐stimulated gene expression and high IFN‐β‐based type‐I IFN. As the trabecular meshwork (TM) is responsible for controlling intraocular pressure (IOP), we examine the effect of IFN‐β on TM cells. Our study is the first to demonstrate that IFN‐β significantly reduced TM cell viability and function by activating autophagy. In addition, anterior chamber injection of IFN‐β remarkably increased IOP level in mice, which can be attenuated by treatments with autophagy inhibitor chloroquine. To uncover the specific mechanism underlying IFN‐β‐induced autophagy in TM cells, we performed microarray analysis in IFN‐β‐treated and DDX58 p.Asp550Ala TM cells. It showed that RSAD2 is necessary for IFN‐β‐induced autophagy. Knockdown of RSAD2 by siRNA significantly decreased autophagy flux induced by IFN‐β. Our findings suggest that DDX58 mutation leads to the overproduction of IFN‐β, which elevates IOP by modulating autophagy through RSAD2 in TM cells.