Jul 2026· Biochimica et biophysica acta. Molecular cell research· Vol 1873, pp.
120197
· 0 citations· 38 references
Medicine
TL;DR
A posttranscriptional regulation of FTH1 by RSL1D1 is unveiled and the implication of RSL1D1/FTH1 in cellular senescence and ferroptosis in diabetic retinopathy in DR is uncovered.
Abstract
Ribosomal L1 domain-containing protein 1 (RSL1D1) is an RNA-binding protein that relates to senescence. Nevertheless, the mechanism of RSL1D1 in modulating senescence and ferroptosis in diabetic retinopathy (DR) remains undefined. The DR mice were developed by intraperitoneal injection of STZ, and AAV targeting RPE was used for gene intervention. ARPE-19 cells were infected using oe-RSL1D1 and sh-FTH1 lentivirus before 30 mM high glucose (HG) exposure. Cell damage was assessed by measuring the expression of senescence and ferroptosis markers in ARPE-19 cells, along with oxidative stress indicators and Fe2+ levels. RSL1D1 and FTH1 expression were significantly reduced in the retinal pigment epithelium (RPE) layer of diabetic mice and HG-induced ARPE-19 cells. Downregulation of RSL1D1 led to RPE cell senescence and dysregulated iron homeostasis-induced ferroptosis. HG treatment reduced the interaction between RSL1D1 protein and FTH1 mRNA in ARPE-19 cells, while RSL1D1 overexpression enhanced this interaction, thereby stabilizing FTH1 mRNA expression. The alleviating effects of RSL1D1 overexpression on retinal pigment epithelium cell senescence and ferroptosis in vitro and in vivo were compromised by FTH1 knockdown. Overall, this study unveils a posttranscriptional regulation of FTH1 by RSL1D1 and uncovers the implication of RSL1D1/FTH1 in cellular senescence and ferroptosis in DR.
Abstract Diabetic retinopathy (DR) is the main cause of vision loss, with retinal pigment epithelial (RPE) cell dysfunction as a key contributor. Ferroptosis is implicated in RPE injury under hyperglycemia; however, its upstream regulatory mechanisms remain unclear. High glucose (HG)‐induced human RPE ARPE‐19 cells and a diabetic mouse model were used. Ferroptosis was assessed through biochemical assays, Western blot, fluorescence probes, and histological staining. Protein interactions and transcriptional regulation were examined using Co‐IP, glutathione S‐transferase pull‐down, ChIP, and luciferase reporter assays. Immunofluorescence staining was used as key indicator expression in retinal tissues. Nuclear receptor 4A1 (NR4A1) expression was upregulated under HG‐induced ARPE‐19 cells. NR4A1 knockdown alleviated HG‐induced iron accumulation, lipid peroxidation, and ferroptosis marker changes. Mechanistically, SMAD‐specific E3 ubiquitin protein ligase 2 (SMURF2) interacted with NR4A1 and promoted its ubiquitination and degradation. Forkhead box O6 (FOXO6) was upregulated by HG and repressed SMURF2 transcription. SMURF2 overexpression mitigated HG‐induced ARPE‐19 ferroptosis and retinal injury in DR mice, an effect reversed by NR4A1 co‐overexpression. SMURF2 knockdown reversed the effect of FOXO6 knockdown on HG‐induced ferroptosis in ARPE‐19 cells and retinal injury in DR mice. The FOXO6–SMURF2–NR4A1 axis critically regulates ferroptosis in RPE cells during DR.
Qiao Chen, Bo Su, Ke Xu et al.· Journal of cell communicatio...· 0 citations
The cKIAA1462/miR-183-5p/HMGB1 axis plays a critical role in diabetic RPE injury by dual regulation of autophagy and pyroptosis by targeting this pathway may offer a novel therapeutic strategy for early diabetic retinopathy.
Lufei Wang, Jia’nan Xie, Longfei Yang et al.· Journal of Translational Med...· 0 citations
PURPOSE
To investigate the role of Frizzled-7 (FZD7) in diabetic retinopathy (DR) and elucidate the molecular mechanism by which FZD7 regulates ferroptosis during disease progression.
METHODS
Core DR-associated genes were identified through integrated bioinformatic analyses and validated by RT-qPCR. Gain- and loss-of-function experiments were performed in high glucose (HG)-treated ARPE-19 cells to investigate the role of the β-catenin/DHODH-FSP1 pathway in FZD7-mediated ferroptosis. In vivo, a streptozotocin-induced DR mouse model was used to assess the effects of pharmacological FZD7 inhibition on retinal ferroptotic injury and pathological changes.
RESULTS
Bioinformatic screening identified four hub genes associated with DR, among which FZD7 was significantly upregulated and further validated in HG-treated ARPE-19 cells. Mechanistically, FZD7 promoted ferroptosis through β-catenin-dependent suppression of the ferroptosis-defense proteins DHODH and FSP1, leading to iron accumulation, oxidative stress, lipid peroxidation, and mitochondrial dysfunction. Conversely, FZD7 silencing restored DHODH and FSP1 expression, attenuated ferroptotic injury, and preserved mitochondrial integrity. Consistent with these findings, pharmacological inhibition of FZD7 in DR mice alleviated retinal ferroptosis, reduced oxidative damage, and improved retinal ultrastructural abnormalities.
CONCLUSIONS
FZD7 drives ferroptotic retinal injury in DR through β-catenin-dependent suppression of the DHODH/FSP1 ferroptosis-defense pathway. Inhibition of FZD7 restores endogenous anti-ferroptotic mechanisms and confers retinal protection, establishing FZD7 as a previously unrecognized therapeutic target for diabetic retinopathy.
Jiaojiao Jiang, Liu Zheng, L. Wang et al.· Journal of Pharmacological S...· 0 citations
Background Age‐related macular degeneration (AMD) is a common degenerative eye disease that eventually leads to irreversible vision loss. CircRNAs have received increasing attention for their regulatory role in AMD. In this study, whole transcriptome sequencing identified differentially expressed circRNA (circMETTL3) in AMD. Previous studies have unlocked the potential mechanism of circMETTL3 in cancer, but its role in AMD has not been studied. Methods ARPE‐19 cells treated with H2O2 were used as the AMD cell model. The senescence, oxidative stress, and DNA damage of ARPE‐19 cells were determined by SA‐β‐gal staining, DCFH‐DA staining, and IF assay. The levels of RPE‐specific markers or mRNA levels were assessed using western blot assay. The potential mechanism of circMETTL3 was investigated by luciferase reporting assay and RIP assay. Results CircMETTL3 was revealed to decrease in AMD cell models. The addition of circMETTL3 decreased SA‐β‐gal staining and ROS production and facilitated cell viability in H2O2‐treated ARPE‐19 cells. Moreover, γH2AX and KRT18 levels were suppressed, and TJP1, BEST1, and CTNNB1 protein levels were increased by circMETTL3 addition. In addition, circMETTL3 could bind to and negatively regulate miR‐100. Overexpression of miR‐100 exacerbated senescence, oxidative stress, and DNA damage in H2O2‐treated ARPE‐19 cells, which reversed the effects of circMETTL3. Furthermore, BMPR2 was targeted by miR‐100. Overexpression of BMPR2 inhibited H2O2‐induced cell damage in ARPE‐19 cells, which reversed the effects of miR‐100. Conclusions In sum, these findings demonstrated that the circMETTL3/miR‐100/BMPR2 axis plays a vital regulatory role in AMD development.
Xiangyang Xin, Xin Zhao, Feng Ling et al.· Journal of Ophthalmology· 0 citations
Diabetic retinopathy (DR), one of the most prevalent microvascular complications of diabetes, is a vision-threatening ocular disease. Although ferroptosis has been implicated in DR development, research on its underlying mechanisms and targeted therapeutics remains limited. Procyanidins, a class of polyphenolic compounds, exhibit robust anti-inflammatory properties and regulatory effects on various pathological processes. Herein, we investigated the potential role of the RNA-binding protein human antigen R (HuR) in mediating ferroptosis during DR progression, as well as the protective effects of Procyanidin C1 (PC1). Streptozotocin-induced diabetic mice and high-glucose-exposed BV2 microglial cells (BV2s) were treated with PC1 to evaluate oxidative stress and the expression of ferroptosis markers. The interaction between HuR and ACSL4 was characterized using ribonucleoprotein (RNP) immunoprecipitation (IP) and mRNA stability assays. Our results demonstrated that PC1 significantly alleviated oxidative stress and ferroptosis in both diabetic mice and high-glucose-treated BV2s. Mechanistically, post-transcriptional regulation by HuR via stabilizing Acsl4 mRNA contributes to the acceleration of ferroptosis during DR progression. Ultimately, PC1 suppresses DR advancement by targeting the HuR-ACSL4 signaling axis, highlighting its potential as a therapeutic intervention.
Qun Liu, Song-Min Wang, Tao Jiao et al.· Experimental Eye Research· 0 citations
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, Fe2⁺ 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.
Sanhua Xu, Jun Huang, Yicang Wang et al.· Biochemical Pharmacology· 0 citations