bims-mideyd 2025-01-12 papers

Curr Mol Med. 2025 Jan 02.

SUMOylation Inhibitors Exert a Protective Effect on Oxidative Damage in Retinal Pigment Epithelial Cells Through the Keap1/Nrf2/ARE Signaling Pathway.

Yilei Liang, Xin Jia, Fangyuan Zheng, Yifan Wang, Yijia Fan, Haiyu Zhang, Ziyao Dang, Lifei Wang.

PURPOSE: To investigate the effect of the SUMOylation inhibitor TAK981 on hydrogen peroxide (H2O2)-induced oxidative damage in human retinal pigment epithelial cells (ARPE-19) and its regulatory mechanism.
METHODS: An oxidative damage model of ARPE-19 cells induced by H2O2 was established, and 1, 2, and 5 µM TAK981 solutions were administered for intervention respectively. Normal cells were used as the control group. The viability of the cells in each group was detected by the methyl thiazolyl tetrazolium (MTT) method. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) in each group of cells were detected by biochemical methods. The levels of IL-1β and TNF-α produced by each group of cells were detected by enzyme-linked immunosorbent assay (ELISA). The protein expression levels of Nrf2, HO-1, NQO-1, Keap1, and Sumo1 in each group of cells were detected by Western blotting. In addition, 2 µM TAK981 and 2 µM TAK981 combined with 10 µM ML385 (an Nrf2 inhibitor) were administered to H2O2-induced ARPE-19 cells, and the levels of SOD and MDA, IL-1β and TNF-αwere detected again.
RESULTS: The viability of the ARPE-19 cells decreased with increasing H2O2 concentration (F=19.158, P<0.001). H2O2 treatment at 350 µM was the concentration at which the cells essentially reached half inhibition (IC50), and the cell oxidative damage model was successfully established. After intervention with TAK981, cell survival increased significantly (F=0.098, P<0.001). The differences between the 2 µM and 5 µM TAK981 groups and the model group were statistically significant (all P<0.01). Compared with those in the normal group, the MDA content in the model group increased, the SOD activity decreased, and the release levels of IL-1β and TNF-α increased (all P<0.01). Compared with those in the model group, the MDA content in the TAK981 group decreased, the SOD activity increased, and the release levels of IL-1β and TNF-α decreased. The differences between the 2 µM and 5 µM TAK981 groups were statistically significant (P<0.05). Compared with those in the normal group, the protein expression levels of Nrf2, HO-1 and NQO-1 in the model group were greater, whereas the protein expression levels of Keap1 and Sumo1 were lower (all P<0.05). Compared with those in the model group, the protein expression levels of Nrf2, HO-1 and NQO-1 in the TAK981-treated group continued to increase, whereas the protein expression levels of Keap1 and Sumo1 continued to decrease. The differences in the 5 µM TAK981 group were statistically significant (P<0.05). In addition, after the combined intervention of TAK981 and ML385 on H2O2-induced cells, compared with the TAK981-only intervention on H2O2-induced cells, the cell viability increased, the MDA content increased, the SOD activity decreased, and the IL-1β and TNF-α release levels increased. The differences were statistically significant (P<0.05).
CONCLUSION: The SUMOylation inhibitor TAK981 activates the Keap1/Nrf2/ARE signaling pathway, enhances the activity of antioxidant enzymes, and reduces the production of oxidative stress products and inflammatory factors, thereby exerting a protective effect on H2O2-induced oxidative damage in ARPE-19 cells. Therefore, it is suggested that intervention in SUMO regulation can be used as a new therapeutic target in the AMD disease model, in order to delay the development of AMD by reducing the oxidative damage of RPE.

Keywords: Nrf2 signaling pathway; Oxidative stress.; Retinal pigment epithelial cells; SUMOylation; TAK981

DOI: https://doi.org/10.2174/0115665240350793241214050904

Exp Eye Res. 2025 Jan 06. pii: S0014-4835(25)00003-X. [Epub ahead of print]251 110232

Senescent retinal pigment epithelial cells promote angiogenesis in choroidal neovascularization via the TAK1/p38 MAPK pathway.

Yinhao Wang, Huiling Ma, Qianjie Yang, Kuangqi Chen, Hui Ye, Xinglin Wang, Jianhua Xia, Xiaodan Chen, Xiawei Wang, Ye Shen, Hongguang Cui.

Senescent retinal pigment epithelial cells play a key role in neovascular age-related macular degeneration (nAMD); however, the mechanisms underlying the angiogenic ability of these cells remain unclear. Herein, we investigated the effects of the senescent adult retinal pigment epithelial cell line-19 (ARPE-19) on wound healing, cell migration and survival, and tube formation abilities of human umbilical vein endothelial cells (HUVECs). Additionally, we used Brown Norway rats to establish a laser-induced choroidal neovascularization (CNV) model for further nAMD-related studies. We found that the wound healing, cell migration, and tube formation abilities of HUVECs were significantly enhanced following culture in conditioned media from senescent ARPE-19 cells; this was attributed to the activation of the transforming growth factor β-activated kinase 1 (TAK1)/p38 MAPK pathway. Consistently, we found that the TAK1 inhibitors 5Z-7-oxozeaenol and takinib reversed the effects of conditioned media from senescent ARPE-19 cells on the wound healing, migration, survival, and tube formation abilities of HUVECs. We further investigated the therapeutic effects of 5Z-7-oxozeaenol on the laser-induced CNV rat model. We found that TAK1 was activated in IB4+ areas in laser-induced CNV lesions; inhibiting the activity of TAK1 using 5Z-7-oxozeaenol significantly alleviated CNV lesion formation and fluorescein leakage in fundus fluorescein angiography and greatly improved a-waves, b-waves, and OP values, as recorded by electroretinography. Thus, senescent RPE cells may promote angiogenesis via the TAK1/p38 MAPK pathway. Further, inhibiting TAK1 expression alleviates pathological neovascularization and improves retinal function in a laser-induced CNV rat model, highlighting the therapeutic potential of this approach for treating nAMD.

Keywords: Neovascularization; Senescence; TAK1; nAMD

DOI: https://doi.org/10.1016/j.exer.2025.110232

Int J Mol Sci. 2024 Dec 20. pii: 13640. [Epub ahead of print]25(24):

IGF-1 Signaling Modulates Oxidative Metabolism and Stress Resistance in ARPE-19 Cells Through PKM2 Function.

Silvia Ravera, Alessandra Puddu, Nadia Bertola, Daniela Verzola, Elisa Russo, Davide Maggi, Isabella Panfoli.

The retinal pigment epithelium (RPE) contributes to retinal homeostasis, and its metabolic dysfunction is implied in the development of retinal degenerative disease. The isoform M2 of pyruvate kinase (PKM2) is a key factor in cell metabolism, and its function may be affected by insulin-like growth factor 1 (IGF-1). This study aims to investigate the effect of IGF-1 on PKM2 modulation of RPE cells and whether co-treatment with klotho may preserve it. ARPE-19 cells, an ex vivo model of human pigmented epithelium, were exposed to IGF-1. Then, we evaluated PKM2 expression, dimerization and subcellular localization, energy metabolism, and redox balance, and whether pre-treatment with Klotho may antagonize the effects of IGF-1. The results show that IGF-1 favors PKM2 dimerization, thus reducing the activity of PKM2 and leading to an altered cellular energy status coupled with reduced oxidative stress. In conclusion, PKM2 plays a pivotal role in the modulation of RPE metabolism and redox balance and could explain the mechanisms through which IGF-1 participates in the pathogenesis of some retinal diseases. Klotho may exert protective effects by mitigating the IGF-1 signal and its effect on mitochondrial function.

Keywords: Klotho; energy metabolism; insulin-like growth factor 1; isoform M2 of pyruvate kinase; redox balance; retinal pigment epithelium

DOI: https://doi.org/10.3390/ijms252413640

Int J Mol Sci. 2024 Dec 19. pii: 13624. [Epub ahead of print]25(24):

Quercetin Alleviates All-Trans-Retinal-Induced Photoreceptor Apoptosis and Retinal Degeneration by Inhibiting the ER Stress-Related PERK Signaling.

Bo Yang, Kunhuan Yang, Ruitong Xi, Jingmeng Chen, Yalin Wu.

All-trans-retinal (atRAL)-induced photoreceptor atrophy and retinal degeneration are hallmark features of dry age-related macular degeneration (AMD) and Stargardt disease type 1 (STGD1). The toxicity of atRAL is closely related to the generation of reactive oxygen species (ROS). Quercetin, a natural product, is known for its potent antioxidant properties; however, its effects in mitigating atRAL-mediated retinal damage remains unclear. This study investigated the protective effects of quercetin against atRAL-induced photoreceptor damage. Using atRAL-loaded 661W photoreceptor cells, we evaluated cell viability, ROS generation, and endoplasmic reticulum (ER) stress under quercetin treatment. Quercetin significantly restored the cell viability (to 70%) and reduced ROS generation in atRAL-treated 661W cells. Additionally, Western blot analysis demonstrated that quercetin mitigated protein kinase RNA-like ER kinase (PERK) signaling, preventing ER stress-induced apoptosis. Importantly, in Abca4-/-Rdh8-/- mice, an animal model of light-induced atRAL accumulation in the retina, quercetin treatment effectively alleviated light-exposed photoreceptor atrophy and retinal degeneration by attenuating PERK signaling. Thus, quercetin protected photoreceptor cells from atRAL-induced damage by inhibiting ROS generation and PERK signaling, which suggests its potential as a therapeutic agent for atRAL-related retinal degeneration.

Keywords: ER stress; all-trans-retinal; apoptosis; photoreceptor; quercetin

DOI: https://doi.org/10.3390/ijms252413624