bims-mideyd 2026-02-08 papers

Arch Pharm Res. 2026 Feb 02.

PF protects retinal pigment epithelial cells from oxidative injury by enhancing mitophagy through a CUL3-dependent AMPK/ULK1 pathway.

Xi Chen, Wei Shi, Yujie Zhu, Kai Li, Ying Xia, Hao Wu, Tianming Hu, Chengyao Qin, Wei Wei.

Mitophagy dysfunction is a critical contributor to retinal pigment epithelial (RPE) cell damage during the progression of retinal degenerative diseases, including age-related macular degeneration (AMD). In this study, we investigated the effects of paeoniflorin (PF) on mitophagy in RPE cells, with a particular focus on the CUL3/LKB1/AMPK/ULK1 signaling pathway. ARPE-19 cells were treated with different concentrations of PF to evaluate cytotoxicity, and its protective effects were further examined in H₂O₂-induced oxidative stress models in vitro and in sodium iodate (NaIO₃)-induced RPE injury models in vivo. Protein levels of CUL3, apoptosis-related factors, mitophagy markers, and components of the LKB1/AMPK/ULK1 pathway were assessed by western blotting, and mitophagy was visualized using MitoTracker labeling. Cycloheximide (CHX) and coimmunoprecipitation (Co-IP) assays were performed to analyze the interaction between CUL3 and LKB1. PF treatment enhanced mitophagy in H₂O₂-stimulated ARPE-19 cells, whereas Parkin knockdown markedly attenuated this effect. In oxidatively damaged cells, PF promoted AMPK and ULK1 phosphorylation, increased mitophagy-associated protein expression, and alleviated mitochondrial dysfunction; these protective effects were abolished by pharmacological inhibition of AMPK or ULK1. In addition, CUL3 overexpression significantly attenuated PF-induced mitophagy activation and reduced PF-associated phosphorylation of LKB1, AMPK, and ULK1. Mechanistically, PF downregulated CUL3 expression, while CUL3 promoted the ubiquitination and degradation of LKB1. Silencing CUL3 induced mitophagy in H₂O₂-treated cells, whereas concurrent knockdown of CUL3 and LKB1 abolished this effect. In vivo, PF mitigated RPE cell loss, enhanced mitophagy, and activated the CUL3/LKB1/AMPK/ULK1 signaling pathway in the retinal tissues of NaIO₃-induced mice. Collectively, these findings indicate that PF protects against RPE injury in an NaIO₃-induced AMD-like model by downregulating CUL3 expression and activating LKB1/AMPK/ULK1-mediated mitophagy.

Keywords: ARPE-19 cells; Age-related macular degeneration (AMD); CUL3; LKB1/AMPK/ULK1; Paeoniflorin (PF); Retinal pigment epithelial (RPE)

DOI: https://doi.org/10.1007/s12272-026-01597-x

J Biochem Mol Toxicol. 2026 Feb;40(2): e70723

Irigenin Modulates BL-Induced Pyroptosis in Retinal Pigment Epithelial Cells Through p38 MAPK and NFκB Pathways.

I-Li Su, Kun-Lin Yeh, Chien-Ying Lee, Sheng-Chien Lin, Chen-Yu Chiang, Chun-Jung Chen, Wen-Ying Chen, Ching-Chi Tseng, Yin-Che Lu, Yu-Hsiang Kuan.

Age-related macular degeneration (AMD), a primary cause of vision loss among older adults, is strongly associated with inflammatory processes. The current study aimed to elucidate the protective effects of irigenin, an isoflavonoid recognized for its anti-inflammatory, antioxidative, antiapoptotic, and anticancer activities, against blue light (BL)-induced damage in N-retinyl-N-retinylidene ethanolamine (A2E)-laden human adult retinal pigment epithelial (A2E-laden ARPE-19) cells. Pretreatment with irigenin markedly mitigated BL-induced cytotoxicity and preserved epithelial barrier function in a concentration-dependent manner. Moreover, irigenin significantly inhibited the expression of proinflammatory cytokines and activation of the nod-like receptor pyrin domain-containing 3 (NLRP3) inflammasome, as evidenced by decreased expression of NLRP3, ASC, and both full-length and cleaved forms of gasdermin D (GSDMD), along with reduced caspase-1 activity. Further mechanistic analyses indicated that irigenin effectively suppressed the activation of the nuclear factor kappa B (NFκB) signaling pathway, as evidenced by phosphorylation of NFκB and inhibitor of NFκB (IκB)α, and both activation and translocation of NFκB, along with reduced phosphorylation of p38 mitogen-activated protein kinase (MAPK). These findings underscore the potential of irigenin to ameliorate BL-induced retinal pigment epithelial cell damage via modulation of inflammation and pyroptosis pathways, suggesting its therapeutic value for preventing AMD.

Keywords: A2E; BL; Irigenin; inflammation; pyroptosis; retinal pigment epithelial cell

DOI: https://doi.org/10.1002/jbt.70723

Biochim Biophys Acta Mol Cell Res. 2026 Jan 28. pii: S0167-4889(26)00017-0. [Epub ahead of print]1873(3): 120121

Shielding retinal pigment epithelium cells from high glucose-induced oxidative stress: the protective effect of phospholipase D (PLD) pathway inhibition.

María S Echevarría, Paula E Tenconi, Vicente Bermúdez, Jorgelina M Calandria, Nicolas G Bazan, Melina V Mateos.

The retinal pigment epithelium (RPE) performs key roles in preserving retinal integrity and must continuously manage oxidative stress (OS). We previously demonstrated that the canonical phospholipase D isoforms, PLD1 and PLD2, mediate the RPE inflammatory response triggered by inflammatory injury. This study explores the mechanisms of modulation of OS mediated by PLD inhibition in RPE cells exposed to high glucose (HG) levels. ARPE-19, D407 and the novel human RPE cell line ABC were cultured under HG (33 mM) or normal glucose (NG, 5.5 mM) conditions. To inhibit PLD1, PLD2, and NADPH oxidase (NOX), VU0359595 (PLD1i), VU0285655-1 (PLD2i), and diphenyleneiodonium chloride (DPI) were used, respectively. HG exposure significantly increased reactive oxygen species (ROS) levels and reduced mitochondrial membrane potential (MMP) in ARPE-19 and D407 cells. These effects were prevented by PLD1i and PLD2i in an Nrf-2 and cyclooxygenase-2 -independent manner. In ARPE-19 cells, DPI prevented OS induced by HG as well as the stress triggered by the combination of phosphatidic acid + diacylglycerol, bioactive lipids generated through the PLD pathway-. Similarly, HG elevated ROS levels in ABC cells, and this increase was prevented by PLD1i and DPI. RNAseq analysis showed differential expression of NOX family members (NOX1,2 and 4 and DUOX1 and 2) in ARPE-19 and ABC cells. Our results demonstrate that PLDs inhibition prevent HG-induced OS in RPE cells, possibly by reducing NOX activity. The PLD pathway constitutes a novel pharmacological target to simultaneously mitigate OS and the inflammatory response, two hallmarks of retinal degenerative diseases.

Keywords: Inflammation; NADPH oxidase; Oxidative stress; Phospholipase D; Retinal pigment epithelium

DOI: https://doi.org/10.1016/j.bbamcr.2026.120121

FEBS Open Bio. 2026 Feb 06.

Dapagliflozin prevents methylglyoxal-induced retinal cell death in ARPE-19 cells.

Naina Trivedi, Zainab Quraishi, Shima Khezri Azizi Far, Madaleine Ward, Aidan Conway, Reem Abdulredha, Eman Mshari, Yousif A Shamsaldeen.

Diabetic macular oedema (DMO) is a sight-threatening complication of diabetes. Current research suggests methylglyoxal (MGO), an advanced glycation end product (AGE) and reactive oxygen species (ROS) precursor produced in states of chronic hyperglycaemia, may contribute to retinal damage in DMO. Dapagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, has shown antioxidant and anti-inflammatory properties in human brain neuronal cells. However, its protective effects in retinal cells remain unclear. This study investigates the potential protective role of current antidiabetics against MGO-induced cytotoxicity in human retinal pigment epithelial cells (ARPE-19), focussing on the NLRP3 and caspase-1 pathway. ARPE-19 cells were studied through four conditions: Control (untreated), MGO (1 nm and 1 mm), cotreatment of MGO (1 mm) with dapagliflozin (10 μm) to investigate cytotoxicity and cell viability through lactate dehydrogenase (LDH) and [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assays, respectively. Cells were further investigated using confocal microscopy to assess the presence and activation of NLRP3 and caspase-1 enzyme. MGO (1 mm) caused significant cytotoxicity by approximately 60%, which was reduced to 33% by dapagliflozin (10 μm), providing a significant level of protection to cells against MGO-induced cytotoxicity, in addition to a significant increase in cell viability from 60% to 83%, and reduction in NLRP3-independent caspase-1 activation and/or expression, associated with increased nuclear staining intensity reflecting potential nuclear condensation and pyroptosis. This study suggests dapagliflozin protects ARPE-19 cells from MGO-induced oxidative stress and inflammasome through reducing caspase-1 activation, underscoring its potential as a therapeutic approach for retinal inflammation and vascular dysfunction in DMO, which requires further clinical investigations.

Keywords: SGLT2 inhibitors; dapagliflozin; diabetes; diabetic macular oedema; inflammasome; retinopathy

DOI: https://doi.org/10.1002/2211-5463.70191