Effects of Siglec-E on parthenolide inhibiting microglia M1 polarization and targeting MAPK/NF-κB pathway / 陆军军医大学学报

ABSTRACT

Objective To explore the impact of the sialic acid binding lectin-E(Siglec-E)on the inhibitory properties of parthenolide(PTL)against lipopolysaccharide(LPS)-induced M1 polarization of microglia(BV2).Methods ①Single cell sequencing data of Siglece related mouse brain tissue was obtained from Gene Expression Omnibus(GEO)database and divided into the WT group(n=3)and the Siglece-/-group(n=4).The microglia cells were screened,and the enrichment analysis was performed to analyze related differential genes and pathways.BV2 cells were constructed by the shRNA interference technique and were divided into NC-shRNA and Siglece-shRNA to detect the expression level of Siglec-E(Siglece).② NC-shRNA and Siglece-shRNA cells were respectively divided into the Control group,LPS group,PTL group and PTL+LPS group(n=3).The mRNA levels of markers of M1 polarization in microglia,iNOS,IL-1 β and IL-6,were detected by RT-qPCR.Siglecefl/fl and Cx3cr1cre mice were mated to obtain microglia-specific Siglece deletion(Siglecefl/fl×Cx3cr1cre)mice,and LPS-induced neuroinflammation model was established.③ Nine WT and Siglecefl/fl×Cx3cr1cre male mice were assigned to the Control group,LPS group and PTL+LPS group(n=3).RT-qPCR,immunofluorescence assay and Western blotting were used to verify the knock-out effect and polarization-related pathways,and to investigate the mechanism of Siglec-E affecting PTL inhibition of M1 polarization of microglia.Results Compared with the NC-shRNA group,the expression of Siglec-E in the Siglece-shRNA group was significantly decreased(P<0.01),indicating that the Siglec-E knock-down cell model was successfully established.With the stimulation of LPS,mRNA levels ofiNOS,IL-1 β and IL-6 were significantly up-regulated compared with the Control group both in shRNA cells and Siglece-shRNA cells(P<0.01).With the influence of PTL and LPS,the markers of M1 polarization in NC-shRNA cells mentioned before were significantly decreased(P<0.05),while for Siglice-shRNA cells,there were no significant changes in the markers of M1 polarization.PTL inhibited the phosphorylation of JNK and IκB protein(P<0.01)and the nuclear translocation of NF-κB in BV2 cells,down-regulated Siglec-E,and weakened the inhibitory effect.Compared with mice in the WT group,the expression of Siglec-E in microglia of Siglecefl/fl×Cx3cr1cre mice was decreased significantly(P<0.01),and the inhibitory effect of PTL on the phosphorylation of NF-κB in microglia of Siglecefl/fl×Cx3cr1cre mice was also decreased.Conclusion The absence of Siglec-E in microglia attenuates the inhibition of M1 polarization by the MAPK/NF-κB pathway targeted by PTL.