TIN2-mediated reduction of mitophagy induces RPE senescence under high glucose

• Published in: Cellular signalling 2024-07, Vol.119, p.111188-111188, Article 111188
• Main Authors: Zhang, Shuchang, Chen, Shimei, Sun, Dandan, Li, Shenping, Sun, Jun, Gu, Qing, Liu, Peiyu, Wang, Xiaoqian, Zhu, Hong, Xu, Xun, Li, Huiming, Wei, Fang
• Format: Article
• Language: English
• Subjects: Animals; Cell Line; Cellular Senescence; Diabetic retinopathy; Diabetic Retinopathy - metabolism; Diabetic Retinopathy - pathology; Glucose - pharmacology; Humans; Male; Mice; Mice, Inbred C57BL; Mitochondria - metabolism; Mitophagy; Mitophagy - drug effects; mTOR; Oxidative Stress; Retinal Pigment Epithelium - metabolism; Senescence; Signal Transduction; Telomere-Binding Proteins - metabolism; TIN2; TOR Serine-Threonine Kinases - metabolism
• ISSN: 0898-6568; 1873-3913
• DOI: 10.1016/j.cellsig.2024.111188

The telomere-associated protein TIN2 localizes to both telomeres and mitochondria. Nevertheless, the impact of TIN2 on retinal pigment epithelial (RPE) cells in diabetic retinopathy (DR) remains unclear. This research aims to examine the role of TIN2 in the senescence of RPE and its potential as a therapeutic target. Western blotting and immunofluorescence staining were utilized to identify TIN2 expression and mitophagy. RT-qPCR was employed to identify senescent associated secretory phenotype (SASP) in ARPE-19 cells infected with TIN2 overexpression. To examine mitochondria and the cellular senescence of RPE, TEM, SA-β-gal staining, and cell cycle analysis were used. The impact of TIN2 was examined using OCT and immunohistochemistry in mice. DHE staining and ZO-1 immunofluorescence were applied to detect RPE oxidative stress and tight junctions. Our research revealed that increased mitochondria-localized TIN2 aggravated the cellular senescence of RPE cells both in vivo and in vitro under hyperglycemia. TIN2 overexpression stimulated the mTOR signaling pathway in ARPE-19 cells and exacerbated the inhibition of mitophagy levels under high glucose, which can be remedied through the mTOR inhibitor, rapamycin. Knockdown of TIN2 significantly reduced senescence and mitochondrial oxidative stress in ARPE-19 cells under high glucose and restored retinal thickness and RPE cell tight junctions in DR mice. Our study indicates that increased mitochondria-localized TIN2 induced cellular senescence in RPE via compromised mitophagy and activated mTOR signaling. These results propose that targeting TIN2 could potentially serve as a therapeutic strategy in the treatment of DR. •Hyperglycemia induced the expression of TIN2 in diabetic retinopathy model.•TIN2 is involved in RPE cell senescence and mitophagy under high glucose.•TIN2 regulates the mTOR signaling pathway.•Knockdown of TIN2 mitigates the senescence of RPE cells in diabetic mice.