Tilianin Reduces Apoptosis via the ERK/EGR1/BCL2L1 Pathway in Ischemia/Reperfusion-Induced Acute Kidney Injury Mice

Zengying Liu; Chen Guan; Chenyu Li; Ningxin Zhang; Chengyu Yang; Lingyu Xu; Bin Zhou; Long Zhao; Hong Luan; Xiaofei Man; Yan Xu

doi:10.3389/fphar.2022.862584

Tilianin Reduces Apoptosis via the ERK/EGR1/BCL2L1 Pathway in Ischemia/Reperfusion-Induced Acute Kidney Injury Mice

Front Pharmacol. 2022 Jun 3:13:862584. doi: 10.3389/fphar.2022.862584. eCollection 2022.

Authors

Zengying Liu¹, Chen Guan¹, Chenyu Li^{1

2}, Ningxin Zhang¹, Chengyu Yang¹, Lingyu Xu¹, Bin Zhou¹, Long Zhao¹, Hong Luan¹, Xiaofei Man¹, Yan Xu¹

Affiliations

¹ Department of Nephrology, the Affiliated Hospital of Qingdao University, Qingdao, China.
² Medizinische Klinik und Poliklinik IV, Klinikum der Universität, LMU München, München, Germany.

Abstract

Background: Acute kidney injury (AKI) is a common syndrome impacting about 13.3 million patients per year. Tilianin has been reported to alleviate myocardial ischemia/reperfusion (I/R) injury, while its effect on AKI is unknown; thus, this study aimed to explore if tilianin protects I/R-induced AKI and the underlying mechanisms. Methods: The microarray dataset GSE52004 was downloaded from GEO DataSets (Gene Expression Omnibus). Differential expression analysis and gene-set enrichment analysis (GSEA) were performed by R software to identify apoptosis pathway-related genes. Then, RcisTarget was applied to identify the transcription factor (TF) related to apoptosis. The STRING database was used to construct a protein-protein interaction (PPI) network. Cytoscape software visualized PPI networks, and hub TFs were selected via cytoHubba. AutoDock was used for molecular docking of tilianin and hub gene-encoded proteins. The expression levels of hub genes were assayed and visualized by quantitative real-time PCR, Western blotting, and immunohistochemistry by establishing I/R-induced AKI mouse models. Results: Bioinformatics analysis showed that 34 genes, including FOS, ATF4, and Gadd45g, were involved in the apoptosis pathway. In total, seven hub TFs might play important roles in tilianin-regulating apoptosis pathways. In in vivo, tilianin improved kidney function and reduced the number of TUNEL-positive renal tubular epithelial cells (RTECs) after I/R-induced AKI. Tilianin reduced the activation of the ERK pathway and then downregulated the expression of EGR1. This further ameliorated the expression of anti-apoptotic genes such as BCL2L1 and BCL2, reduced pro-apoptotic genes such as BAD, BAX, and caspase-3, and reduced the release of cytochrome c. Conclusion: Tilianin reduced apoptosis after I/R-induced AKI by the ERK/EGR1/BCL2L1 pathway. Our findings provided novel insights for the first time into the protective effect and underlying molecular mechanisms of tilianin on I/R-induced AKI.

Keywords: EGR1; ERK; acute kidney injury; apoptosis; ischemia–reperfusion injury; tilianin.