Schema of symptoms and signaling relationship between mother and placenta in preeclampsia. Aberrant AT1-mediated signaling in maternal vasculature and/or shallow invasion of trophoblasts makes the placenta hypoxic. In response, placental villous units produce sFlt1, sEng, and other proinflammatory cytokines that flow into maternal circulation, leading to systemic endothelial dysfunction. The increase of shear stress in fetoplacental site due to maternal hypertension further aggravates the whole system.