Effects of Listeria monocytogenes LIPI-4 on the expression of inflammasome in brain and brain microvascular endothelial cells
ObjectiveTo explore the effect of Listeria monocytogenes Pathogenicity island 4(LIPI-4)on the expression of inflamma-some in brain microvascular endothelial cells.Methods Mice were intraperitoneally injected with bacteria Lm928 and Lm928ΔLIPI-4.The content of Evans blue(EB)in brain tissue was detected by methylphthalamide ultraviolet spectrophotometry,the level of Myelin basic protein(MBP)in serum was detected by ELISA,and the expression of NLRP3,AIM2,NLRC4,inflammatory factors IL-1β,IL-18,etc.in brain tissue was detected by qRT-PCR.qRT-PCR,Western Blot,and ELISA were used to detect the inflammasome re-lated molecules and inflammatory factors expression of human brain microvascular endothelial cells(HCMEC/D3)infected by Lm928、Lm928ΔLIPI-4 and CLm928ΔLIPI-4.Results After 36 h of infection with Lm928,EB content in the mouse brain significantly in-creased.After 72 h of infection with Lm928,the serum MBP content was significantly higher than that of the Lm928ΔLIPI-4 group(P<0.01).The qRT-PCR results showed that the mRNA expression levels of NLRC4 and IL-1β in the Lm928 group were significant-ly higher than those in the Lm928ΔLIPI-4 group(P<0.05).In infected HCMEC/D3 cells,the mRNA expression levels of NLRP3 and IL-1β in the Lm928 group were significantly higher than those in the Lm928ΔΔLIPI-4 group(P<0.01);The Western blot re-sults showed that the protein expression levels of NLRP3 and NLRC4 in the Lm928 group were significantly higher than those in the Lm928ΔLIPI-4 group(P<0.01);The secretion of IL-1β in the HCMEC/D3 supernatant of the Lm928 group was significantly higher than that of the Lm928ΔLIPI-4 group(P<0.01).Conclusion Listeria monocytogenes LIPI-4 participates in the NLRP3/NLRC4/IL-1β pathway,activates inflammasomes to participate in inflammatory responses,damages brain tissue and brain microvascular endotheli-al cells,and destroys the blood-brain barrier.
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