CircRNA itchy E3 ubiquitin protein ligase improves mitochondrial dysfunction in sepsis-induced acute kidney injury by targeting microRNA-214-3p/ATP-binding cassette A1 axis

BACKGROUND: Circular RNAs (circRNAs) are promising biomarkers and therapeutic targets for acute kidney injury (AKI). In this study, we investigated the mechanism by which circRNA itchy E3 ubiquitin protein ligase (circ-ITCH) regulates sepsis-induced AKI. METHODS: A sepsis-induced AKI mouse model was created using LPS induction and circ-ITCH overexpression. Circ-ITCH levels were confirmed via RT-qPCR. Kidney tissue changes were examined through various stains and TUNEL. Enzyme-linked immunosorbent assay (ELISA) gauged oxidative stress and inflammation. Mitochondrial features were studied with electron microscopy. RT-qPCR and western blotting assessed mitochondrial function parameters. Using starBase, binding sites between circ-ITCH and miR-214-3p, as well as miR-214-3p and ABCA1, were predicted. Regulatory connections were proven by dual-luciferase assay, RT-qPCR, and western blotting. RESULTS: Circ-ITCH expression was downregulated in LPS-induced sepsis mice. Overexpression of circ-ITCH ameliorates indicators of renal function (serum creatinine [SCr], blood urea nitrogen [BUN], neutrophil gelatinase-associated lipocalin [NGAL], and kidney injury molecule-1 [Kim-1]), reduces renal cell apoptosis, mitigates oxidative stress markers (reactive oxygen species [ROS] and malondialdehyde [MDA]), and diminishes inflammatory markers (interleukin [IL]-1β, IL-6, and tumor necrosis factor [TNF-α]). Moreover, circ-ITCH overexpression alleviated mitochondrial damage and dysfunction. Furthermore, circ-ITCH acts as a sponge for miR-214-3p, thereby upregulating ABCA1 expression. In addition, the miR-214-3p inhibitor repressed oxidative stress, inflammation, and mitochondrial dysfunction, which was reversed by circ-ITCH knockdown. Further cellular analysis in HK-2 cells supported these findings, highlighting the protective role of circ-ITCH against sepsis-induced AKI, particularly through the miR-214-3p/ABCA1 axis. CONCLUSION: The novel circ-ITCH/miR-214-3p/ABCA1 pathway plays an essential role in the regulation of oxidative stress and mitochondrial dysfunction in sepsis-induced AKI.