Inhibition of lncRNA PVT1 alleviates calcium oxalate crystal-induced renal injury and inflammation through the miR-23b-3p/CCL7 axis

BACKGROUND: Long non-coding RNAs (lncRNAs) contribute to kidney stone pathogenesis, especially through functioning as competitive endogenous RNAs (ceRNAs). Previously, the differentially expressed lncRNAs and mRNAs were identified in patients with calcium oxalate (CaOx) nephrolithiasis, and the lncRNA PVT1/miR-23b-3p/CCL7 ceRNA network was identified. Our study aimed to validate the function of this ceRNA network in cellular model of CaOx nephrolithiasis. METHODS: HK-2 cells were were treated with CaOx monohydrate (COM) crystals to establish an in vitro model of CaOx-induced renal tubular epithelial cell injury. Cell viability, LDH release, apoptosis, oxidative stress, inflammation, and renal tubular epithelial injury were assessed using CCK-8 assay, LDH assay, flow cytometry, oxidative stress-related biochemical assays, ELISA, and western blotting. The interactions among PVT1, miR-23b-3p, and CCL7 were investigated using bioinformatics prediction, dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays. RESULTS: Our results showed that CaOx treatment increased PVT1 and CCL7 expression but decreased miR-23b-3p expression in human proximal tubular epithelial (HK-2) cells. PVT1 directly bound to miR-23b-3p and upregulated CCL7 expression. PVT1 knockdown or miR-23b-3p overexpression alleviated CaOx-induced HK-2 cell injury and apoptosis, oxidative stress, and inflammation. MiR-23b-3p downregulation or CCL7 overexpression antagonised the suppression of PVT1 silencing on CaOx-induced HK-2 cell injury and apoptosis, oxidative stress, and inflammation. CONCLUSION: Collectively, PVT1 knockdown ameliorates CaOx-mediated renal cell damage through the miR-23b-3p/CCL7 axis. Our finding might provide novel targets for treating kidney stones.