Silencing of microRNA-375 affects immune function in mice with liver failure by upregulating astrocyte elevated gene-1 through reducing apoptosis of Kupffer cells.

This study aims to investigate how microRNA-375 (miR-375) improves immune function by regulating liver macrophages (Kupffer cells) in mice with liver failure. Forty mice were divided into ConA-1h, ConA-3h, ConA-6h, and control groups, with 10 mice in each group. Mice models of liver failure were established by injecting concanavalin A (ConA) solution via the tail veins of mice, and then primary Kupffer cells were isolated and cultured. Reverse transcription quantitative polymerase chain reaction, Western blot analysis, and enzyme-linked immunosorbent assay were conducted to examine the expressions of miR-375, astrocyte elevated gene-1 (AEG-1), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and IL-1 beta in Kupffer cells of mice with liver failure as well as after silencing of miR-375. Flow cytometry was used to determine cell apoptosis. During the liver failure process, miR-375, IL-6, TNF-alpha, and IL-1 beta expressions were increased over time, while AEG-1 expression decreased over time in the control, ConA-1h, ConA-3h, and ConA-6h groups. Opposite alternations were observed after silencing of miR-375. Dual-luciferase reporter gene assay showed that AEG-1 was a target gene of miR-375. Flow cytometry determination showed that the ratio of apoptotic Kupffer cells decreased after silencing of miR-375. Overexpression of AEG-1 could rescue the suppression of IL-6, TNF-alpha, and IL-1 beta expressions in Kupffer cells after the short-term induction of ConA and further inhibit cell apoptosis. Our study provides evidence that miR-375 could regulate Kupffer cells to improve immune function in mice with liver failure.