114. Toll-like receptor 9 agonist suppresses angiogenesis by differentially regulating VEGFA and sFLT1 in preeclampsia

Abstract

Introduction 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; sFLT1 (soluble vascular endothelial growth factor receptor 1) is an important antiangiogenic protein factor. Objective To determine whether TLR9 inhibits angiogenesis at the feto-maternal interface under conditions of preeclampsia. Methods 1. Patients: We detected the placental levels of TLR9, VEGFA and sFLT1 in preeclamptic and normal women. 2. In vivo experiment: We used TLR9 agonists ODN1826 to establish a PE-like mouse model. And then we evaluated the regulation of VEGFA and sFLT1 in the placentas of PE-like mouse model. 3. In vitro experiment: We explored the regulation of VEGFA and sFLT1 in ODN2006-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. Placental TLR9 and sFLT1 levels were upregulated while VEGFA levels were downregulated in women with PE. 2. ODN1826 could induce PE-like symptoms in pregnant mice. And ODN1826 could activate TLR9 signalling and induce upregulated sFLT1 levels, downregulated VEGFA levels in the placentas of PE-like mouse model. 3. ODN2006 could activate TLR9 signalling and induce increased sFLT1 levels, decreased VEGFA levels in the HTR-8/SVneo cells. And TLR9 siRNA could upregulate VEGFA levels and downregulate sFLT1 levels in the HTR-8/SVneo cells. Silencing TLR9 promotes the migration and invasion of HTR-8/SVneo cells. Discussion TLR9 is profoundly capable of suppressing angiogenesis by differentially regulating the expression of VEGFA and sFLT1 at the feto-maternal interface, potentially contributing to the development of PE.