Abstract:Aim To investigate the effects of platelet factor 4 (PF4) on the expression of Toll like receptors 2 (TLR2) in human umbilical vein endothelial cells-ECV304. Methods The effects of PF4 on the expression of TLR2 in ECV304 were determined by reverse-transcription polymerase chain reaction,Western Blotting and immunohistochemistry analysis. Results In comparison with blank group,the levels of TLR2 mRNA and protein upregulated (n=5,P><0.05) in time dependent manner in PF4 (100 μg/L) group,but it could not be inhibited by heparin. Using immunohistochemical staining and image analysis methods,the TLR2 expression in ECV304 in PF4 group was increased compared with blank group(0.060 399±0.020 998 vs 0.001 385±0.000 953,P><0.05). Conclusion PF4 promotes the expression of TLR2 mRNA and protein in human umbilical vein endothelial cells. The result of study is useful for platelet to play effect on innate immunity in chronic inflammatory such as atherosclerosis.

Abstract:Aim To investigate the effects of streptococcus mutans on the expression of toll-like receptor 2(TLR2),TLR4,interleukin-6(IL-6) and IL-8 in EAhy926 cells(the human endothelial hybridoma of human umbilical vein endothelial cells(HUVEC) and the human epithelial cell line A549,characterized by endothelial phenotype and biology). Methods EAhy926 cells were treated with Streptococcus mutans.The mRNA expression of TLR2,TLR4,IL-6 and IL-8 in EAhy926 cells was detected by reverse transcription polymerase chain reaction(RT-PCR).TLR2 and TLR4 were analyzed by flow cytometry.The production of IL-6 and IL-8 in the cultured supernatants was measured by biochemical method and ELISA respectively.TLR2 and TLR4 blocking assay was used to investigate the relationship between IL-6,IL-8 and TLR2,TLR4 mRNA expression. Results The expression of mRNA and protein for TLR2 and TLR4 in EAhy926 cells increased after stimulated by Streptococcus mutans,peaked the maximal level at 6 h(P><0.05),and then decreased.The expression of IL-6 and IL-8 mRNA was significantly induced when exposed to Streptococcus mutans,reaching the maximal level at 12 h,respectively(P><0.05).Meanwhile,Streptococcus mutans induced the production of IL-6 and IL-8 with peaking at 12 h(P><0.01).The mRNA expression of IL-6 and IL-8 in EAhy926 cells was significantly blocked by anti-human TLR2 and anti-TLR4. Conclusion Streptococcus mutans upregulated the expression of TLR2 and TLR4 and induced the production of inflammatory cytokines IL-6 and IL-8.The expression of TLR2 and TLR4 of EAhy926 cells may elicit a TLR2 and TLR4-mediated innate immune response and contribute to production of inflammatory cytokines IL-6 and IL-8.