bims-mideyd 2026-01-04 papers

Antioxidants (Basel). 2025 Nov 28. pii: 1434. [Epub ahead of print]14(12):

HDGF Protects Retinal Pigment Epithelium from Glyoxal-Induced Ferroptosis via SIRT1/PGC-1α/Nrf2 Pathway.

Heng-Dao Lin, Rong-Kung Tsai, Yao-Tseng Wen, Pei-Kang Liu.

Age-related macular degeneration (AMD) is driven in part by the accumulation of reactive metabolites like glyoxal (GO), which induces retinal pigment epithelium (RPE) degeneration. Here, we demonstrate that GO triggers ferroptosis in human ARPE-19 cells, as characterized by iron-dependent lipid peroxidation, glutathione depletion, and reactive oxygen species (ROS) accumulation. This ferroptotic cell death is coupled with profound mitochondrial dysfunction, featuring network fragmentation and the downregulation of the key regulators MFN2, PGC-1α, and SIRT1. We identify hepatoma-derived growth factor (HDGF) as a potent protector against GO-induced damage. HDGF operates through a dual mechanism: it activates the p38 MAPK/AKT and SIRT1/PGC-1α axes to restore mitochondrial biogenesis and homeostasis, while concurrently enhancing the glutathione/GPX4 antioxidant system to suppress ferroptosis. This cytoprotective action is mediated via the PGC-1α/Nrf2 pathway, which integrates the enhancement of antioxidant defenses with the preservation of mitochondrial integrity. Our findings establish HDGF as a novel therapeutic agent for AMD, uniquely capable of concurrently targeting the interconnected pathways of ferroptosis and mitochondrial dysfunction, thereby addressing a critical unmet need in retinal disease treatment.

Keywords: age-related macular degeneration (AMD); ferroptosis; glyoxal (GO); hepatoma-derived growth factor (HDGF); mitochondria function; reactive oxygen species (ROS)

DOI: https://doi.org/10.3390/antiox14121434

FASEB J. 2026 Jan 15. 40(1): e71387

Thalidomide Synergistically Regulates Cell Cycle and Endoplasmic Reticulum Stress to Alleviate RPE Oxidative Damage Through the E2F2-FBXO5 Pathway.

Jingya Zhu, Xinyue Yu, Chaojuan Wen, Youao Zhang, Xielan Kuang, Nan Sun, Shiyu Tang, Bing Xiao, Sainan Xiao, Xun Wang, Kaili Wu, Qingjiong Zhang, Huangxuan Shen.

Thalidomide, a glutamate derivative with teratogenicity, possesses anti-inflammatory, immunomodulatory, and anti-angiogenic properties that enable its use in treating refractory diseases unresponsive to conventional therapies. Dry age-related macular degeneration (AMD), characterized by retinal pigment epithelium (RPE) degeneration and lacking effective therapies, represents a significant unmet medical need. Our findings demonstrated that thalidomide significantly restores mitochondrial function, alleviates G2/M phase cell cycle arrest, and suppresses sustained endoplasmic reticulum (ER) stress in oxidatively injured RPE cells. Mechanistically, these effects are coordinated through E2F2 activation, which subsequently regulates FBXO5 expression. Moreover, thalidomide was able to ameliorate oxidative stress-induced retinal structural disorders and RPE degeneration, and improve visual function in mice. In summary, this study elucidates that thalidomide synergistically regulates cell cycle progression and endoplasmic reticulum homeostasis through the E2F2-FBXO5 signaling pathway, providing a new drug candidate and therapeutic target for the prevention and treatment of dry AMD.

Keywords: age‐related macular degeneration (AMD); cell cycle; endoplasmic reticulum stress; oxidative stress; thalidomide

DOI: https://doi.org/10.1096/fj.202502444R

Biomedicines. 2025 Dec 08. pii: 3004. [Epub ahead of print]13(12):

Proteasome and Ribosome Ubiquitination in Retinal Pigment Epithelial (RPE) Cells in Response to Oxidized Low-Density Lipoprotein (OxLDL).

Francesco Giorgianni, Sarka Beranova-Giorgianni.

Background/Objectives: Oxidative stress plays a significant role in the development and progression of age-related macular degeneration (AMD). Retinal pigment epithelium (RPE) cells are specialized multifunctional cells indispensable for the maintenance of vision. The dysfunction and death of RPE cells in the macula characterize the onset and development of AMD. Of the various toxic agents that impact the health of the RPE, particular focus has been given to various forms of lipoproteins and their cytotoxic derivatives normally present in the retina. Oxidized low-density lipoprotein (OxLDL), derived from LDL in a pro-oxidative environment, is found adjacent to RPE cells as part of drusen, extracellular deposits that are a hallmark feature of AMD. OxLDL is a potent inflammatory agent and it has been implicated in cardiovascular and neurodegenerative conditions. The cellular molecular mechanisms triggered by OxLDL are only partially understood. The focus of this study was to characterize changes in the proteome of RPE cells after exposure to OxLDL, with a focus on the characterization and quantification of ubiquitinated proteins. Methods: Identification and quantification were performed with a high-resolution LC-MS/MS-based proteomics workflow after immune-enrichment for ubiquitinated peptides. Results: In total, out of the more than 1000 RPE ubiquitinated peptides quantified, OxLDL treatment caused a significant increase in ubiquitinated peptides compared to LDL and untreated cells. Principal component analysis (PCA) of the differentially ubiquitinated proteins (265) reduced the data complexity in two main groups of variables (proteins). Conclusions: Gene ontology enrichment analysis of the grouped proteins with the highest loading contribution to principal component 1 (PC1) and principal component 2 (PC2) revealed significant ubiquitination changes upon OxLDL treatment in proteins of the ubiquitin-proteasome system (UPS) responsible for proteasome-mediated catabolic processes and in protein members of the cellular translation machinery.

Keywords: UPS; drusen; oxidative stress; oxidized LDL; proteasome; proteome; proteostasis; retinal pigment epithelium; ribosome; ubiquitin

DOI: https://doi.org/10.3390/biomedicines13123004

Cell Death Dis. 2025 Dec 31.

CRX is an intrinsic suppressor of epithelial‒mesenchymal transition in retinal pigment epithelial cells: a promising therapeutic avenue for subretinal fibrosis.

Dongli Li, Qingjian Ou, Furong Gao, Xi Wang, Lilin Zhu, Ye Zhou, Jing-Ying Xu, Caixia Jin, Juan Wang, Jieping Zhang, Jiao Li, Yanlong Bi, Lixia Lu, Guo-Tong Xu, Haibin Tian.

The epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells is one of the significant pathogenic mechanisms for the formation of subretinal fibrosis in age-related macular degeneration (AMD). Multiple signaling pathways that promote EMT have been well described, yet the endogenous signaling pathways that inhibit EMT within RPE cells remain largely elusive. In this study, we confirmed the expression of CRX in human RPE cells and human embryonic stem cell-derived RPE (ESC-RPE) cells. By employing sub-culture to disrupt intercellular connections and thereby inhibit the Hippo signaling pathway, combined with TGF-β1 treatment in vitro to mimic the microenvironment for the formation of subretinal fibrosis, it was revealed that Hippo/YAP1 and TGF-β1 synergistically promoted the nuclear translocation of β-catenin, and the latter bound to TCF7 to inhibit the expression of CRX. Overexpression of CRX was capable of suppressing the occurrence of EMT in ESC-RPE cells. CRX exerted its inhibitory effect on EMT partly by upregulating the expression of PPP2R2B. In the laser-induced choroidal neovascularization mouse model, the nuclear translocation of CRX took place in RPE cells, and overexpression of CRX played an inhibitory role in the formation of subretinal fibrosis. This study has identified CRX as an endogenous signaling molecule that inhibits EMT in RPE cells and has provided a new research target and treatment strategy for the treatment of wet AMD and the inhibition of subretinal fibrosis formation.

DOI: https://doi.org/10.1038/s41419-025-08352-y

Exp Eye Res. 2025 Dec 29. pii: S0014-4835(25)00590-1. [Epub ahead of print]264 110817

Assessing the barrier function of the retinal pigment epithelium in adult mice using transepithelial electrical resistance measurements and quantitative immunohistochemistry.

Chunxu Yuan, Shuo Yuan, Karin Dedek.

The retinal pigment epithelium (RPE) plays a crucial role in the homeostasis of the vertebrate retina as its tight junctions form the outer blood-retina barrier and regulate the movement of substances between the blood and the neural retina. However, the outer blood-retina barrier breaks down in many degenerative retinal diseases, likely due to oxidative stress. This leads to fluid accumulation and inflammation in the retina. As mouse models are important for studying degenerative retinal diseases, methods to assess the integrity of RPE tight junctions in the mouse are needed. In this study, we established a system to measure the transepithelial electrical resistance (TEER) in mouse RPE using an Ussing chamber. We validated the sensitivity of the TEER measurements by adding oxidative stress-related substances, such as lipopolysaccharide and interleukin-1β, to the apical chamber. We used the same substances, which are known to affect tight junction proteins, to study their effect on the morphological integrity of the hexagonal RPE array in a flat-mount preparation. Antibody stainings for zonula occludens-1, claudin-1, and connexin 43 revealed morphological aberrations with an increased number of abnormal intersections after incubation with interleukin-1β. To further quantify this effect, we devised a new method to measure the angular deviations from the hexagonal RPE cell array. In summary, our results show that TEER and quantitative immunohistochemistry effectively assess the barrier function in mouse RPE and allow analyzing mouse models for retinal degeneration in the future.

Keywords: Barrier function; Paracellular transport; RPE; Retina; Tight junctions; Transepithelial resistance

DOI: https://doi.org/10.1016/j.exer.2025.110817