β-arrestin 2 attenuates lipopolysaccharide-induced liver injury via inhibition of TLR4/NF-κB signaling pathway-mediated inflammation in mice

AIM: To study the role and the possible mechanism of β-arrestin 2 in lipopolysaccharide (LPS)-induced liver injury in vivo and in vitro. METHODS: Male β-arrestin 2(+/+) and β-arrestin 2(-/-) C57BL/6J mice were used for in vivo experiments, and the mouse macrophage cell line RAW264.7 was used for in vitro experiments. The animal model was established via intraperitoneal injection of LPS or physiological sodium chloride solution. Blood samples and liver tissues were collected to analyze liver injury and levels of pro-inflammatory cytokines. Cultured cell extracts were collected to analyze the production of pro-inflammatory cytokines and expression of key molecules involved in the TLR4/NF-κB signaling pathway. RESULTS: Compared with wild-type mice, the β-arrestin 2 knockout mice displayed more severe LPS-induced liver injury and significantly higher levels of pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and IL-10. Compared with the control group, pro-inflammatory cytokines (including IL-1β, IL-6, TNF-α, and IL-10) produced by RAW264.7 cells in the β-arrestin 2 siRNA group were significantly increased at 6 h after treatment with LPS. Further, key molecules involved in the TLR4/NF-κB signaling pathway, including phospho-IκBα and phosho-p65, were upregulated. CONCLUSION: β-arrestin 2 can protect liver tissue from LPS-induced injury via inhibition of TLR4/NF-κB signaling pathway-mediated inflammation.