UCHL1通过去泛素化和稳定NRF2来抑制氧化应激诱导的视网膜血管内皮细胞铁死亡，从而减轻糖尿病视网膜病变。

Abstract

Diabetic retinopathy (DR) is characterized by progressive retinal microvascular injury, with oxidative stress and ferroptosis increasingly recognized as key pathogenic contributors. This study investigated whether ubiquitin C-terminal hydrolase L1 (UCHL1) regulates retinal endothelial ferroptosis through stabilization of nuclear factor erythroid 2-related factor 2 (NRF2). Analysis of the GSE102485 dataset identified UCHL1 as a downregulated deubiquitinating enzyme in DR. Streptozotocin-induced type 1 diabetic mice and high glucose (HG)-induced human retinal capillary endothelial cells (HRCECs) were used, together with UCHL1 inhibition/knockdown, AAV-mediated UCHL1 overexpression, and NRF2 knockdown. UCHL1 expression was reduced in diabetic retinas and HG-induced HRCECs, accompanied by ferroptosis activation, mitochondrial injury, and endothelial dysfunction. Pharmacological inhibition or siRNA-mediated depletion of UCHL1 intensified oxidative stress, Fe 2 ⁺ accumulation, lipid peroxidation, mitochondrial fragmentation, and cristae disruption, while impairing endothelial barrier integrity, migration, and tube formation. In vivo, LDN57444 aggravated retinal vascular leakage and fundus vascular abnormalities, whereas AAV-UCHL1 preserved retinal architecture and reduced vascular permeability. Mechanistically, co-immunoprecipitation and ubiquitination assays demonstrated that UCHL1 interacted with NRF2 and stabilized NRF2 by removing K48-linked polyubiquitin chains. Nuclear-cytoplasmic fractionation further showed that UCHL1 overexpression restored NRF2 abundance and increased nuclear NRF2 accumulation under HG conditions. Ferrostatin-1 rescued UCHL1 depletion-induced ferroptotic injury, whereas NRF2 knockdown abolished the protection conferred by UCHL1 overexpression. These findings highlight the UCHL1/NRF2 axis may represent a therapeutic target in DR.