Inhibition of oxidative stress-induced epithelial-mesenchymal transition in retinal pigment epithelial cells of age-related macular degeneration model by suppressing ERK activation

Ya-Chi Yang; Yueh Chien; Aliaksandr A Yarmishyn; Lee-Yieng Lim; Hao-Yu Tsai; Wen-Chuan Kuo; Ping-Hsing Tsai; Sheng-Hsien Yang; Shao-I Hong; Shih-Jen Chen; De-Kuang Hwang; Yi-Ping Yang; Shih-Hwa Chiou

doi:10.1016/j.jare.2023.06.004

Inhibition of oxidative stress-induced epithelial-mesenchymal transition in retinal pigment epithelial cells of age-related macular degeneration model by suppressing ERK activation

J Adv Res. 2023 Jun 15:S2090-1232(23)00167-4. doi: 10.1016/j.jare.2023.06.004. Online ahead of print.

Authors

Affiliations

¹ Department of Medical Research, Taipei Veterans General Hospital, Taipei 112201, Taiwan; College of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan.
² Department of Medical Research, Taipei Veterans General Hospital, Taipei 112201, Taiwan.
³ Department of Medical Research, Taipei Veterans General Hospital, Taipei 112201, Taiwan; Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan.
⁴ Institute of Biophotonics, College of Biomedical Science and Engineering, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan.
⁵ Department of Medical Research, Taipei Veterans General Hospital, Taipei 112201, Taiwan; College of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan; Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan.
⁶ College of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan; Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112201, Taiwan.
⁷ Department of Medical Research, Taipei Veterans General Hospital, Taipei 112201, Taiwan; College of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan; Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan. Electronic address: molly0103@gmail.com.
⁸ Department of Medical Research, Taipei Veterans General Hospital, Taipei 112201, Taiwan; College of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan; Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan; Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112201, Taiwan; Genomic Research Center, Academia Sinica, Taipei 115024, Taiwan. Electronic address: shchiou@vghtpe.gov.tw.

PMID: 37328058
DOI: 10.1016/j.jare.2023.06.004

Abstract

Introduction: Epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells is related to the pathogenesis of various retinopathies including age-related macular degeneration (AMD). Oxidative stress is the major factor that induces degeneration of RPE cells associated with the etiology of AMD.

Objectives: Sodium iodate (NaIO₃) generates intracellular reactive oxygen species (ROS) and is widely used to establish a model of AMD due to the selective induction of retinal degeneration. This study was performed to clarify the effects of multiple NaIO₃-stimulated signaling pathways on EMT in RPE cells.

Methods: The EMT characteristics in NaIO₃-treated human ARPE-19 cells and RPE cells of the mouse eyes were analyzed. Multiple oxidative stress-induced modulators were investigated and the effects of pre-treatment with Ca²⁺ chelator, extracellular signal-related kinase (ERK) inhibitor, or epidermal growth factor receptor (EGFR) inhibitor on NaIO₃-induced EMT were determined. The efficacy of post-treatment with ERK inhibitor on the regulation of NaIO₃-induced signaling pathways was dissected and its role in retinal thickness and morphology was evaluated by using histological cross-sections and spectral domain optical coherence tomography.

Results: We found that NaIO₃ induced EMT in ARPE-19 cells and in RPE cells of the mouse eyes. The intracellular ROS, Ca²⁺, endoplasmic reticulum (ER) stress marker, phospho-ERK, and phospho-EGFR were increased in NaIO₃-stimulated cells. Our results showed that pre-treatment with Ca²⁺ chelator, ERK inhibitor, or EGFR inhibitor decreased NaIO₃-induced EMT, interestingly, the inhibition of ERK displayed the most prominent effect. Furthermore, post-treatment with FR180204, a specific ERK inhibitor, reduced intracellular ROS and Ca²⁺ levels, downregulated phospho-EGFR and ER stress marker, attenuated EMT of RPE cells, and prevented structural disorder of the retina induced by NaIO₃.

Conclusions: ERK is a crucial regulator of multiple NaIO₃-induced signaling pathways that coordinate EMT program in RPE cells. Inhibition of ERK may be a potential therapeutic strategy for the treatment of AMD.

Keywords: Calcium signaling; Epithelial growth factor receptor; Extracellular signal-regulated kinase; FR180204; Reactive oxygen species; Retinopathy.