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

Abstract 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‐α (TNF‐α), and IL‐1β 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‐α, and IL‐1β 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‐α, and IL‐1β 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.