GuaLou GuiZhi decoction represses LPS-induced BV2 activation via miR-155 induced inflammatory signals

Abstract

Inflammatory response that occur post-ischemia is a serious problem in the treatment of ischemic brain disease. MicroRNA-155 is a brain-specific or brain-enriched miRNA, which mediates inflammatory reactions in cerebral ischemic tissue by regulating inflammatory signal and the expression level of SOCS1. The present study was aimed to assess the effect of GuaLou GuiZhi Decoction (GLGZD) on miR-155 expression in activated microglia following inflammation and further explore the role of GLGZD on expression of the inflammation-related gene. BV2 cells were used to simulated by LPS to make the inflammatory model. Expression level of miR-155 was detected by Real-Time PCR. BV2 cells after simulated by LPS were then transfected with miR-155 mimic and its negative controls. Cytokines release were measured by corresponding purchased ELISA kits, respectively. Then target protein expression of miR-155 were detected by western blotting assay. After miRNA over expression transfections, expressions of inflammationrelated factors, SOCS-1 and SAMD in BV2 cells after activation were measured by Western blot assay. Results showed that in BV2 cells after simulated by LPS, miR-155 was upregulated. The elevated miR-155 expression enhanced the inflammatory cytokine release. miR-155 directly target and negatively regulated SOCS-1 and SMAD-1 expression. Over expression of SOCS-1 and SMAD reduced inflammatory action that was enhanced by miR-155 mimic transfection. miR155 was positively related with activation of NF-κB signal pathways via SOCS-1 and SMAD. In conclusion, GuaLou GuiZhi Decoction (GLGZD) might exert its anti-inflammatory action by inhibiting the expression of miR-155, indicating that miR-155 may be used as a treatment target in clinical treatment with GuaLou GuiZhi Decoction (GLGZD) in ischemic brain.