Metformin regulates the LIN28B‑mediated JNK/STAT3 signaling pathway through miR‑140‑3p in subretinal fibrosis

Zhijuan Hua; Wenchang Yang; Dongli Li; Yixin Cui; Lu Shen; Lingna Rao; Yuxiang Zheng; Qiying Zhang; Wenyi Zeng; Yi Gong; Ling Yuan

doi:10.3892/etm.2023.12227

Metformin regulates the LIN28B‑mediated JNK/STAT3 signaling pathway through miR‑140‑3p in subretinal fibrosis

Exp Ther Med. 2023 Sep 27;26(5):528. doi: 10.3892/etm.2023.12227. eCollection 2023 Nov.

Authors

Zhijuan Hua^{1

2}, Wenchang Yang¹, Dongli Li¹, Yixin Cui¹, Lu Shen¹, Lingna Rao¹, Yuxiang Zheng¹, Qiying Zhang¹, Wenyi Zeng¹, Yi Gong³, Ling Yuan¹

Affiliations

¹ Department of Ophthalmology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, P.R. China.
² Department of Pediatric Ophthalmology, The Affiliated Hospital of Yunnan University, Kunming, Yunnan 650021, P.R. China.
³ Department of Physiology, School of Basic Medical Sciences, Kunming Medical University, Kunming, Yunnan 650500, P.R. China.

Abstract

Subretinal fibrosis (SF) is an important cause of submacular neovascularization that leads to permanent vision loss, but has no effective clinical treatment. The present study examined the influence of metformin on SF, and investigated whether the mechanism involves the microRNA (miR)-140-3p/LIN28B/JNK/STAT3-mediated regulation of oxidative stress, angiogenesis and fibrosis-associated indicators. A mouse model of laser-induced SF was established. In addition, an ARPE-19 fibrotic cell model was established using TGF-β1. A Cell Counting Kit-8 assay was used to examine cell viability. Flow cytometry was used to measure reactive oxygen species levels, and western blotting was used to detect the levels of proteins associated with epithelial-mesenchymal transition (EMT), signaling and fibrosis. The levels of superoxide dismutase, malondialdehyde, glutathione-peroxidase and catalase were measured using kits. Scratch assays and Transwell assays were used to assess cell migration and invasion, respectively, and reverse transcription-quantitative PCR was used to determine the levels of miR-140-3p and LIN28B. Dual-luciferase assays were used to verify the targeting relationship between miR-140-3p and LIN28B, and coimmunoprecipitation was used to confirm the interaction between LIN28B and JNK. Masson staining and hematoxylin and eosin staining were used to examine collagenous fibers and the histopathology of eye tissue. In ARPE-19 cells induced by TGF-β1, metformin promoted miR-140-3p expression and inhibited LIN28B expression and JNK/STAT3 pathway activation, thereby inhibiting oxidative stress, EMT and fibrosis in ARPE-19 cells. The overexpression of LIN28B or treatment with the JNK/STAT3 agonist anisomycin partially reversed the inhibitory effect of metformin on oxidative stress and fibrosis in ARPE-19 cells. The dual-luciferase reporter assay and coimmunoprecipitation assay showed that miR-140-3p targeted the 3' untranslated region of LIN28B mRNA and inhibited LIN28B expression. LIN28B targeted and bound to JNK and regulated the JNK/STAT3 pathway. Therefore, it may be concluded that metformin can promote miR-140-3p expression, inhibit LIN28B and then inhibit the JNK/STAT3 pathway to alleviate SF.

Keywords: JNK/STAT3; LIN28B; metformin; miR-140-3p; subretinal fibrosis.

Grants and funding

Funding: The study was supported by The Applied Basic Research Foundation of the Department of Science, Technology of Yunnan Province, Yunnan, China (grant no. 202201AY070001-036), the National Natural Science Foundation Project (grant no. 82260207) and Scientific Research Fund of Education Department of Yunnan Province (grant no. 2023J0036).