Metallothionein 3 regulates cuproptosis in rat retinal ischemia-reperfusion injury via the Atox1–ATP7a axis

Abstract

Retinal ischemia–reperfusion injury (RIRI) is a major pathologic process leading to visual impairment and even blindness. Its pathogenesis is complex, and effective targeted therapeutic approaches remain limited. Cuproptosis, a recently identified form of regulated cell death, has not been fully characterized in the context of RIRI. This study aimed to investigate whether metallothionein 3 (MT3) influences the pathogenesis of RIRI by regulating the antioxidant 1–copper-transporting adenosine triphosphatase alpha (Atox1–ATP7a) axis, thereby modulating cuproptosis. Using transcriptomic sequencing and bioinformatic analysis, combined with a rat RIRI model, R28 cell culture, recombinant MT3 protein rescue experiments, and complementary molecular biologic assays, this study provided evidence that cuproptosis occurs in retinal ganglion cells (RGCs) following RIRI. Moreover, MT3 expression was markedly downregulated in retinal Müller cells. This downregulation was associated with impaired function of the Atox1–ATP7a copper transport axis, decreased copper ion efflux, and enhanced cuproptosis-related injury in Müller cells, ultimately exacerbating retinal damage. This study explains the in-depth mechanisms by which MT3 regulates cuproptosis through the Atox1–ATP7a axis in RIRI. These findings suggest that MT3 may serve as a promising novel therapeutic target for the treatment of RIRI.