Role and mechanism of vimentin in neonatal meningitis induced by group B streptococcus / 中国生物制品学杂志

ABSTRACT

@#Objective To evaluate the role of vimentin(Vim)in neonatal meningitis induced by group B streptococcus(GBS)and explore its molecular mechanism,so as to provide experimental basis for the prevention and treatment of GBS neonatal meningitis. Methods Human brain microvascular endothelial cells(HBMECs)were used as the cell model,the Vim knockdown strain was constructed by transfection of Vim small interfering RNA(siRNA)sequence into HBMECs,and NC siRNA group transfected with negative control sequence was set at the same time. The inhibitory effect of Vim was detected by Western blot and immunofluorescence assay. After 48 h of transfection,the cells were infected with GBS at a MOI of 100,and adhesion and invasion tests were performed 2 h and 3 h after infection,respectively. After 3 h of infection,the effect of Vim inhibition on NF-κB p65 nuclear translocation in HBMECs was measured by Western blot and immunofluorescence assay,and the effect of Vim inhibition on ERK pathway activation related proteins and inflammatory factors in HBMECs was detected by Western blot. Results Compared with the control group,the Vim protein level and fluorescence intensity in HBMECs of Vim siRNA group significantly decreased(t = 3. 242 and 71. 51,P < 0. 05 and < 0. 001,respectively). Compared with NC siRNA + GBS group,the adhesion rate and invasion rate of Vim siRNA + GBS group decreased significantly(t = 9. 949 and 30. 050,respectively,each P < 0. 001);the phosphorylated p65 level decreased significantly(t = 2. 824,P < 0. 05),the nuclear translocation of p65 protein was inhibited,and the intensity of green fluorescence in nucleus decreased significantly;the levels of TNF-α,IL-6 and phosphorylated ERK1/2 proteins were significantly inhibited(t = 4. 000,6. 367 and 3. 872,respectively,each P < 0. 05). Conclusion Inhibition of Vim can reduce the adhesion and invasion of GBS to HBMECs,inhibit the activation of NF-κB and ERK signaling pathway and the production of downstream inflammatory factors,thus reducing the damage of GBS to HBMECs.