bims-mideyd 2026-01-25 papers

Mol Biol Rep. 2026 Jan 20. 53(1): 309

Protective role of zingerone against high glucose-Induced retinal pigment epithelial cell damage through modulation of the TRPM2 channel pathway.

Esmanur Çiğ, Mahmut Yardımcı, Ramazan Çınar, Kenan Yıldızhan, Kenan Yıldızhan.

BACKGROUND: Diabetic retinopathy (DRP) is a leading cause of vision loss associated with chronic hyperglycemia-induced oxidative stress (OS), inflammation, and mitochondrial dysfunction in retinal pigment epithelium (RPE) cells. Zingerone (ZGN), a phenolic compound derived from Zingiber officinale, exhibits potent antioxidant and anti-inflammatory properties; however, its molecular targets in diabetic retinal damage remain unclear.
METHODS: This study investigated the protective effects of ZGN against high glucose (HG)-induced cytotoxicity in human ARPE-19 cells, focusing on the ROS/PARP-1/TRPM2 signaling pathway. The cells were exposed to HG (30 mM) and treated with ZGN (0-80 µM) for 24 h.
RESULTS: HG incubation significantly increased MDA, PARP-1, ROS, intracellular calcium ion ([Ca²⁺]i), and pro-inflammatory cytokines (IL-1β and TNF-α) in ARPE-19 cells, while decreasing GSH levels and cell viability. ZGN significantly restored OS, reduced cytokine release, [Ca²⁺]i, and preserved mitochondrial membrane potential. Western blot and fluorescence analyses showed that ZGN reduced TRPM2 protein expression and suppressed [Ca²⁺]i overload. Moreover, pharmacological inhibition of TRPM2 with 2-APB and of PARP-1 with DPQ enhanced the cytoprotective effects of ZGN, confirming that the ROS/PARP-1/TRPM2 axis mediates HG-induced oxidative damage.
CONCLUSIONS: These findings suggest that ZGN protects ARPE-19 cells by integrating OS with [Ca²⁺]i homeostasis, providing a mechanistic rationale for its potential therapeutic use in preventing OS-related retinal damage in DRP.

Keywords: ARPE-19 cell; Diabetic retinopathy; Oxidative stress; TRPM2 channel; Zingerone

DOI: https://doi.org/10.1007/s11033-026-11476-9

J Neurochem. 2026 Jan;170(1): e70358

Isoform-Specific Splicing of ANK2 by PTBP2 Orchestrates Retinal Pigment Epithelial-to-Neuron Fate Conversion.

Yun-Xi Ma, Yan-Ke Zhang, Jun Li, Bing-Lin Zhu.

Direct lineage reprogramming represents a promising strategy to convert somatic cells into neurons, offering regenerative potential. While transcription factor-based approaches have been extensively studied, the role of post-transcriptional regulation, particularly alternative splicing (AS), in neuronal fate acquisition remains poorly defined. Here, we demonstrate that the concurrent knockdown of the splicing regulator PTBP2 and the barrier protein p53 enhances the neuronal conversion of human retinal pigment epithelial (hRPE-19) cells when combined with ASCL1 and miR-9/9*-124 (AMnp). Transcriptomic and splicing analyzes reveal that PTBP2 depletion induces widespread AS changes, most notably promoting near-complete inclusion of exon 36 in the ANK2 gene, which encodes a key regulator of axon initial segment assembly. Functional and rescue assays confirm that loss of exon 36 significantly impairs neuronal induction, whereas re-expression restores neuronal conversion efficiency, establishing ANK2 isoform switching as a mechanistic requirement for reprogramming. Moreover, photoreceptor markers expression in AMnp-reprogrammed neurons suggests partial photoreceptor-like features potentially reflecting residual epigenetic memory, with chromatin remodeling potentially cooperating with splicing to influence subtype specification. These findings identify the PTBP2-ANK2 splicing axis as an isoform-specific molecular switch for RPE-to-neuron conversion, offering a strategy to enhance the precision and efficiency of neuronal reprogramming.

Keywords: ANK2; PTBP2; RPE cells; Transdifferentiation; alternative splicing

DOI: https://doi.org/10.1111/jnc.70358

Methods Mol Biol. 2026 Jan 23.

Differentiation of Retinal Pigment Epithelium (RPE) and Retinal Organoids from Human iPSCs.

Katy Linkens, Cécile Méjécase, Mariya Moosajee.

In recent decades, human-induced pluripotent stem cell (iPSC) technology has revolutionized in vitro disease modeling and personalized medicine, enabling the generation of patient-specific "disease-in-a-dish" systems across a wide range of tissues, including retinal pigment epithelium (RPE) and retinal organoids. Numerous protocols have been developed for iPSC-RPE and retinal organoid differentiation, typically involving prolonged culture durations, low overall efficiency, and reliance on multiple extrinsic signaling factors. Here we describe an RPE differentiation protocol over 6 weeks, incorporating three additional factors, followed by pigment isolation to isolate differentiated RPE cells for subsequent maturation. After 4 weeks of maturation, the resulting monolayer is well polarized, exhibiting hexagonal cobblestone morphology, expressing canonical RPE markers. We also describe an effective of retinal organoid differentiation protocol, using nicotinamide and a stepwise reduction of KnockOut™ Serum Replacement (KOSR) concentration over the first 9 days, that facilitates the initiation of retinal differentiation in challenging iPSC lines.

Keywords: Human-induced pluripotent stem cells; IRD; Inherited retinal diseases; RPE; Retinal organoids; Retinal pigment epithelium; iPSC

DOI: https://doi.org/10.1007/7651_2025_674

Hum Cell. 2026 Jan 21. 39(2): 37

Ethambutol induces optic neuropathy through SDHB-mediated ferroptosis in retinal ganglion cells via Smad4 pathway.

Qiushi Li, Wei Ge, Yifan Zhang, Qibin Xu, Junli Xu, Yu Zhang, Xingneng Guo, Wenyan Sheng, Liwei Zhu.

Ethambutol (EMB)-induced optic neuropathy (EON) is a clinical concern. Ferroptosis, involving iron and toxic reactive oxygen species (ROS), causes unique cell death, but its mechanism in EON is unclear. This study aims to explore the EON mechanisms. Wistar rats were used to establish an EON model by administering EMB at 50 mg/kg daily for 8 weeks. Retinal ganglion cells (RGC-5 cells) were used for in vitro experiments. Histological staining, MTT assays, flow cytometry, western blot analysis, dual-luciferase reporter assay, chromatin immunoprecipitation, and high-throughput sequencing were conducted to investigate cell death modes and molecular changes. EMB treatment leads to significant cell loss and structural damage in RGCs of EON model, predominantly through ferroptosis. We confirm increased ROS levels, downregulation of SLC7A11 and GPX4, and decreased glutathione (GSH) levels, upregulation of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) levels in EMB-treated RGC-5 cells. Furthermore, sequencing data reveal that in RGC-5 cells treated with EMB, the differentially expressed genes (DEGs) primarily exhibited alterations in biological functions associated with metabolism, stress response, and apoptotic regulation. Specifically, EMB inhibits the expression of succinate dehydrogenase enzyme B (SDHB), thereby disrupting antioxidant defenses and facilitating ferroptosis. Moreover, Smad4 has been pinpointed as a pivotal transcription factor in regulating SDHB expression. Notably, its interaction with the promoter region of SDHB is inhibited by EMB. This study provides compelling evidence for the involvement of ferroptosis in EON and highlights SDHB and Smad4 as potential therapeutic targets for mitigating this adverse effect.

Keywords: Ethambutol; Ferroptosis; Optic neuropathy; Retinal ganglion cells; SDHB

DOI: https://doi.org/10.1007/s13577-025-01342-4