The Possible Mechanism Of Toll-like Receptor 9 In Preeclampsia

Objective:Preeclampsia(PE)is a common pregnancy-specific disorder characterized by elevated blood pressure and proteinuria.Activation of the maternal immune system and impaired placental angiogenesis are thought to contribute to the pathogenesis of PE.Toll-like receptor 9(TLR9)plays a role in innate immunity,defending the organism against infection.VEGFA(vascular endothelial growth factor A)is the most important proangiogenic factor;s FLT1(soluble vascular endothelial growth factor receptor 1)is an important antiangiogenic protein factor.The purpose of this study is to determine whether TLR9 inhibits angiogenesis by suppressing VEGFA and promoting s FLT1 expression at the maternal-fetal interface under conditions of PE.Methods:1.Patients and tissue collection:Human placental tissues were obtained from women with a normal pregnancy(N=28)or PE(N=22)who were delivered by elective cesarean section.Then we detected the placental levels of TLR9,VEGFA,s FLT1 and pro-inflammatory factors(IL-6,TNF-α,IP-10)in preeclamptic and normal women.2.In vivo experiment:We used TLR9 agonists ODN1826 to establish a PE-like mouse model and examined the blood pressure,proteinuria,fetal development,H&E staining of kidney and placenta in the mouse model.Mice received intraperitoneal injections of ODN1826 on E7.5,E9.5,and E11.5.And then we evaluated the regulation of VEGFA,s FLT1 and several pro-inflammatory factors(IL-6,TNF-α,IP-10)in the placentas of PE-like mouse model.3.In vitro experiment : We explored the regulation of VEGFA and s FLT1 in Cp G-ODN-stimulated cells and si-TLR9-transfected cells.And then we evaluated the effect of si-TLR9 on human trophoblast migration/invasion through transwell assay and wound healing assay.Results:1.Compared to normal women,preeclamptic women had markedly higher levels of TLR9,IL-6,TNF-α,and IP-10 in the placenta.2.Placental s FLT1 levels were upregulated and VEGFA levels were downregulated in women with PE.3.ODN1826 could used to established a PE-like mouse model;it induces hypertension,proteinuria,fetal growth restriction,fetal malformation,placental and kidney disorder in mouse.4.Compared to normal group,PE-like mouse model had higher levels of TLR9,NF-κB p65,IL-6,TNF-α,and IP-10 in the placenta.5.Placental s FLT1 levels were upregulated and VEGFA levels were downregulated in PE-like mouse model.6.ODN2006 treatment of HTR8/SVneo cells significantly increased TLR9 and NF-κB p65 expression in cells.7.VEGFA levels were decreased and s FLT1 levels were increased in ODN2006-treated HTR8/SVneo cells.8.VEGFA levels were increased and s FLT1 levels were decreased in the si-TLR9 group compared to the negative control group;silencing TLR9 promotes the migration and invasion of HTR-8/SVneo cells.Conclusions:1.The alterd expression of TLR9,s FLT1,VEGFA may play a role in the development of preeclampsia in human beings.2.ODN1826 could induce PE-like symptoms in pregnant mice.And ODN1826 could activate TLR9 signalling and induce upregulated s FLT1 levels,downregulated VEGFA levels in the placentas of PE-like mouse model.3.ODN2006 could activate TLR9 signalling and induce increased s FLT1 levels,decreased VEGFA levels in the HTR-8/SVneo cells.And TLR9 si RNA could upregulate VEGFA levels and downregulate s FLT1 levels in the HTR-8/SVneo cells.Silencing TLR9 promotes the migration and invasion of HTR-8/SVneo cells.4.TLR9 is profoundly capable of suppressing angiogenesis by differentially regulating the expression of VEGFA and s FLT1 at the feto-maternal interface,potentially contributing to the development of PE.