血胆固醇水平异常升高孕妇HDL颗粒的功能变化及其通过HDL-氧化固醇抑制胎儿发育的胎盘机制

Other researchers and our team have studied that gestational hypercholesterolemia impaired the placental function and might be related to the fetal growth restriction，but the mechanisms are unclear. The present study hypothesized that the HDL subclasses and compositions were changed in hypercholesterolemic pregnant women and then the antioxidantive and antiinflammative function of HDL particals were impaired. So, pregnant women in early gestation were recruited and the birth cohort was established to confirm the risk of genstational hypercholesterolemia on fetal growth. And then HDL partical was separated from pregnant women by polyacrylamide gel electrophoresis, lipidomic and proteomic analyzing the composition, and the antioxidative ability were also measured in vitro. The HDL subclasses and distribution in normal and hypercholesterolemic pregnancy were studied by MRI. The relationship of HDL particals levels and birthweight were analyzed by multivariable linear regression and the OR value for fetal growth restriction was calculated by logistic regression. .The zebrafish were fed with control or high cholesterol diet, and the embyo were injected with HDL particals from FGR or hypercholesterolemic pregnant. The embryonic development, zygote division, the oxidative and inflamitive state and genes expression related to lipid transported were measured. Finally, HDL from hypercholesterolemic or FGR pregnant women and 27-hydroxycholesterol were used to treat cultured trophoblast cells, effects on the cell division, differentiation, and lipid metabolism were studied.

孕期血胆固醇水平异常升高（GHC）危害胎儿发育和子代健康，但机制不清，课题组前期研究表明HDL-C水平异常升高和胎盘功能紊乱可能是主要原因。本研究拟在已建立队列基础上扩大样本量，采用核磁共振仪分析孕妇血清HDL颗粒及其亚类的含量；密度梯度超离心分离HDL颗粒并检测其脂质组、蛋白组构成和抗氧化功能、气质联用色谱检测氧化固醇水平，研究GHC孕妇HDL颗粒的分布和功能变化及其与新生儿体重的关系及胎儿生长受限（FGR）发生的风险；分别用GHC和FGR孕妇的HDL颗粒和氧化固醇处理斑马鱼胚胎及人滋养层细胞，观察斑马鱼的存活率、畸形率、血管生成等，检测氧化应激、细胞生长和分化、IGF1R-PI3K/AKT信号通路等指标，同时检测GHC和FGR孕妇胎盘组织中上述指标及胎盘形态、血管密度等，确定HDL颗粒及氧化固醇对胎盘血管生成、胚胎发育和细胞分化的影响，揭示孕期血胆固醇水平异常升高抑制胎儿发育的机制。

孕期血胆固醇水平异常升高（Gestational high cholesterol, GHC）危害胎儿发育和子代健康，课题组前期研究表明HDL-c水平异常升高和胎盘功能紊乱可能是主要原因。采用密度梯度超离心法分离GHC孕妇的HDL颗粒，研究HDL颗粒的分布和功能变化及其与新生儿体重的关系。本研究通过人群研究发现孕早期血清HDL2-c水平新生儿出生体重负相关；尤其是孕早期HDL-c、HDL2-c水平及HDL2-c/HDL3-c比值增加降低LGA发生风险；孕24-28周和孕35-36周HDL-c水平与BW负相关，孕35-36周HDL-c水平升高增加SGA发生风险；孕期HDL-c变化趋势与新生儿体型较小相关。发现高胆固醇血症组孕妇血清中总胆固醇、总氧化固醇、27-OHC的水平显著高于对照组。额外人群研究发现，脂质代谢基因的遗传多态性对超生理高胆固醇血症(Maternal supraphysiologic hypercholesterolemia, MSPH)的发生风险具有显著贡献。孕期过高的HDL-c和PC(16：0/0：0)浓度被认为影响早孕期胎盘循环的可能生物标志物，同时我们在孕期母体生理性高胆固醇血症(Maternal physiological hypercholesterolemia, MPH)和MSPH受试者之间进行了巢式病例对照研究，研究母胎脂代谢基因遗传多态性与MSPH发病风险相关性以及孕早期母体血清和UV血清脂质组学的差异。动物研究发现，孕早期高TC孕妇来源的HDL抑制胚胎发育；HDL2是HDL抑制胚胎发育作用的关键亚组分，而HDL3干预的斑马鱼胚胎中这种抑制作用并不明显。我们用GHC孕妇血清的HDL颗粒和氧化固醇处理斑马鱼胚胎及人滋养层细胞，结果发现HDL颗粒及氧化固醇抑制胎盘血管生成、胚胎发育和细胞分化，揭示了孕期血胆固醇水平异常升高抑制胎儿发育的机制。我们给CD-1小鼠皮下注射27-OHC可抑制孕鼠胎盘和胎鼠的正常发育情况。最后通过细胞研究发现高胆固醇血症孕妇血清、高浓度HDL和oxHDL可能是通过调控MAPK1/3信号通路抑制BeWo细胞合体化，进而对胎盘功能和胎儿生长发育产生不利影响。同时研究发现细胞内源和外源的27-OHC可激活PI3K/AKT/mTOR信号通路抑制滋养细胞分化融合。