Microglia activation in paraventricular nucleus of hypothalamus: A self-help strategy for fetus born to preeclamptic mother

Preeclampsia (PE) is a life-threatening pregnancy-specific disorder, characterized by new-onset hypertension after 20 weeks of gestation. It has been generally acknowledged that failure of uterine spiral arteries remodeling, imbalance of pro-angiogenic and anti-angiogenic substances are engaged in the early stage of PE. Nevertheless, the exact pathogenesis remains poorly understood. Recent evidence shows that microglial activation in the paraventricular nucleus of hypothalamus (PVN) is associated with neuroinflammation and enhanced sympathetic excitation, which contribute to the hypertensive status in many diseases with PE included. In our recent work, we sequenced fetus-derived exosomal microRNA (miRNA) profiles and found that 181 miRNAs were significantly downregulated in women with PE. Among these miRNAs, miR-216a-5p exhibited the most significant fold change and may regulate CCCTC-binding factor (ctcf), the pivotal molecule in microglia activation. In conclusion, we hypothesize that fetuses under compromised uteroplacental environment may release exosomal miRNAs, activate microglia in maternal PVN, enhance sympathetic excitation and result in elevated maternal blood pressure, which participate in the occurrence and development of PE, however, guarantee the adequate blood supply to fetuses themselves. More basic research regarding this hypothesis may open up a new direction for the study of the pathogenesis of PE and is expected to provide a new theoretical basis for early diagnosis and treatment of PE. One day, would the changes of specific miRNAs be discovered through portable device may help the early diagnosis of PE or be the marker of prognosis of worsened PE.