C5aR antagonist inhibits occurrence and progression of complement C5a induced inflammatory response of microglial cells through activating p38MAPK and ERK1/2 signaling pathway

Y. Liu, S.-Q. Xu, W.-J. Long, X.-Y. Zhang, H.-L. Lu

Department of Pediatrics, Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. lyan3022@outlook.com

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• Pharmacology

OBJECTIVE: To discuss the effect of complement C52 (C5a) and complement C5a receptor (C5aR) antagonists on inflammatory status of mouse microglial cells.

MATERIALS AND METHODS: Primary culture was performed on mouse microglial cells. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay was used to detect effect of C5a and C5aR antagonists on vitality of microglial cells. The effect of C5a and C5aR antagonists on mRNA expression of p38MAPK and ERK1/2 was determined using quantitative PCR (qPCR). Enzyme linked immunosorbent assay (ELISA) was used to measure expression of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in cells.

RESULTS: According to quantitative fluorescent PCR, relative expression of p38MAPK and ERK1/2 mRNA in C5a antagonist treatment group was significantly higher compared to normal group and C5a+C5aR antagonist treatment group (p<0.05). However, the relative expression of the C5a+C5aR antagonist treatment group was significantly lower compared to that of the normal group (p<0.05). Expression of Iba1, p-p38MAPK and p-ERK1/2 proteins in C5a antagonist treatment group was significantly higher than normal group, in C5a+C5aR antagonist treatment group was lower than C5a antagonist treatment group (p<0.05). There were significant differences for IL-6 and TNF-α levels among 5 groups (p<0.05). Expression of cytokines was the highest in 100 nM C5a antagonist treatments and lowest in normal group.

CONCLUSIONS: Complement C5a upregulated expression of inflammatory factors in mouse microglial cells, while C5aR antagonist inhibited occurrence and progression of inflammatory status. This was achieved by affecting transcriptional and translational processes of different factors in p38MAPK and ERK1/2 signaling pathway.

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