The Mechanisms And Intervention Strategy Of Preeclampsia Induced By Glucocorticoid Exposure

Background:Preeclampsia(PE)is a pregnancy-specific disease characterized by hypertension,proteinuria and multiple system dysfunction,which is one of the important causes of morbidity and mortality in pregnant women and fetuses.Due to the unclear etiology and pathogenesis of PE,there are currently no effective preventive and therapeutic measures in clinical practice except for early termination of pregnancy.Glucocorticoid(GC)is elevated during pregnancy and plays an important role in the regulation of embryo implantation,pregnancy maintenance and fetal maturation.However,GC needs to be controlled at a certain level during pregnancy,high GC exposure can inhibit the miaratipn and invasion of placental trophoblast and is related to fetal growth restriction and PE.11β-hydroxy-steroid dehydrogenase type 2(11β-HSD2),a major GC metabolizing enzyme in the placenta,can convert active GC into inactive form,thereby preventing the placenta from being exposed to high GC.In addition,maternal exposure to high GC can reach the placenta due to stress or use of GC class drugs during pregnancy.Our previous studies have shown that abnormal placental GC metabolism and maternal high GC exposure can cause PE in pregnant rats,but the mechanism is unclear and intervention strategies need to be studied.Therefore,the two parts of this study aimed to investigate the mechanisms and intervention strategy of PE induced by high glucocorticoid exposure.Methods:In the first part of this study,we explored the molecular mechanism and intervention strategy of PE caused by abnormal placental GC metabolism using a pregnant rat model of PE induced by 11β-HSD2 inhibitor Carbenoxolone(CBX),hereafter referred to as CBX model.In the second part of this study,we explored the molecular mechanism and intervention strategy of PE caused by maternal high GC exposure using a pregnant rat model of PE induced by a synthetic GC dexamethasone(DEX),hereafter referred to as DEX model.We conducted transcriptomic and metabolomic testing and combined analysis of the two models and further experimental verification,and formulated intervention strategies to explore the efficacy and mechanism of PE induced by placental 11β-HSD2 dysfunction and maternal high glucocorticoid,respectively.Results:1.The mechanisms and intervention strategy of preeclampsia induced by placental 11β-HSD2 dysfunctionCombined transcriptome and metabolome analysis showed that mitochondrial oxidative phosphorylation(OXPHOS)and glutathione metabolism were the core changes in the placenta of CBX model.Further studies showed that OXPHOS complex I,III and IV were down-regulated in the placenta of CBX model,and the metabolome targeting central carbon metabolism confirmed the decreased metabolites such as pyruvate and citric acid.Mitochondrial function detection showed that the generation of reactive oxygen species(ROS)increased in the placenta of CBX model,while ATP and mitochondrial membrane potential(MMP)decreased.All of the above suggest that placental mitochondrial dysfunction occurs in the CBX model.Given that excess ROS is a central link in mitochondrial dysfunction,we subsequently investigated the effect of mito TEMPO,a mitochondrial-targeted antioxidant that scavenges mitochondrial ROS,on the CBX model.Results showed that mito TEMPO alleviated CBX-induced PE-like symptoms,pathological analysis of the placenta showed that spiral artery remodeling and placental vascular network were improved,and doppler ultrasound showed that mito TEMPO promoted uterine placental blood perfusion.Multiomics analysis showed that mito TEMPO improved OXPHOS and glutathione metabolism and reversed 11β-HSD2 downregulation in the placenta of CBX models.Mitochondrial dysfunction,decreased Mitochondrial DNA(mt DNA)content and downregulation of mitochondrial inner membrane fusion protein Opa1 in placenta of CBX model were reversed by mito TEMPO.Morever,we found that 11β-HSD2 dysfunction resulted in impaired migration and invasion,and caused mitochondrial dysfunction,decreased mt DNA and Opa1 in cultured human extravillous trophoblast(EVT)cells,all of which could be improved by mito TEMPO.Of note,the knockdown of Opa1 resulted in mitochondrial dysfunction and impaired migration and invasion function in EVT,and 11β-HSD2 dysfunction decreased transcriptional activity of Opa1.2.The mechanisms and intervention strategy of preeclampsia induced by maternal high glucocorticoid exposureOmics analysis revealed significant changes in placental mitochondrial OXPHOS and cytokine-cytokine receptor pathways in DEX model.Further studies showed that OXPHOS complex I,II,III and IV were down-regulated in the placenta of DEX model,mitochondrial dysfunction also occurred,manifested by increased ROS production and decreased ATP and MMP.We also studied the effect of mito TEMPO on the DEX model,subsequently.Results showed that mito TEMPO alleviated placental mitochondrial dysfunction in the DEX model,improved maternal spiral artery(SA)flow,alleviated maternal hypertension and renal injury,but did not improve fetal umbilical artery flow and fetal growth restriction and elevated circulating s Flt1 and s Eng.Multi-omics analysis and verification showed that mito TEMPO could improve cell response to oxidative stress and glutathione metabolism in placenta of DEX model,and reverse complex II and IV.However,it could not improve the changes of glucose transporter Slc2a3,glycolysis key enzyme Hk1,pentose phosphate pathway key enzyme TKT and their metabolites in the placenta of DEX model,nor could it reverse the increase of Il1,Tnf-α and prostaglandin E2 in circulation,and the decrease of growth factors such as Igf2 and Igf2 r.In cultured human EVT,we found that mito TEMPO could partially improve mitochondrial dysfunction,the reduction of OXPHOS complex I,II,IV and mt DNA content,and eventually restore the migration and invasion ability of EVT.Conclusion:(1)Placental mitochondrial dysfunction is a common change in the molecular mechanism of PE caused by abnormal placental GC metabolism and high maternal GC exposure,and is the core mechanism of placental GC metabolism abnormality leading to PE.(2)In PE induced by abnormal placental GC metabolism,mitochondrial dysfunction of the placenta leads to insufficient invasion of the placental trophoblast and helical artery remodeling,which subsequently leads to placental abnormalities and elevated levels of anti-angiogenic factors,leading to a series of PE-like symptoms.(3)In maternal PE induced by high GC exposure,placental mitochondrial dysfunction leads to inadequate invasion of the placental trophoblast and dysfunction of spiral artery remodeling,leading to maternal symptoms such as hypertension and kidney injury.Increased levels of antiangiogenic factors may be associated with placental inflammation,and fetal growth restriction may be caused by failure to reprogram placental glucose metabolism,as well as down-regulation of placental growth factors and placental inflammation.(4)Targeting mitochondrial ROS effectively alleviates PE induced by abnormal placental GC metabolism and alleviates maternal-like symptoms of PE induced by high maternal GC exposure,but does not improve fetal growth restriction.Therefore,more detailed classification and more precise treatment of PE are needed,so as to treat PE more effectively.