Immunology and Pathophysiology, Otto Loewi Research Center for Vascular Biology, Immunology and Inflammation, Medical University of Graz, Austria.
Department of Obstetrics and Gynecology, Medical University of Graz, Austria.
Biochim Biophys Acta Mol Cell Biol Lipids. 2018 Sep;1863(9):968-979. doi: 10.1016/j.bbalip.2018.05.005. Epub 2018 May 18.
Gestational diabetes mellitus (GDM) is associated with excessive oxidative stress which may affect placental vascular function. Cholesterol homeostasis is crucial for maintaining fetoplacental endothelial function. We aimed to investigate whether and how GDM affects cholesterol metabolism in human fetoplacental endothelial cells (HPEC). HPEC were isolated from fetal term placental arterial vessels of GDM or control subjects. Cellular reactive oxygen species (ROS) were detected by HDCFDA fluorescent dye. Oxysterols were quantified by gas chromatography-mass spectrometry analysis. Genes and proteins involved in cholesterol homeostasis were detected by real-time PCR and immunoblotting, respectively. Cholesterol efflux was determined from [H]-cholesterol labeled HPEC and [C]-acetate was used as cholesterol precursor to measure cholesterol biosynthesis and esterification. We detected enhanced formation of ROS and of specific, ROS-derived oxysterols in HPEC isolated from GDM versus control pregnancies. ROS-generated oxysterols were simultaneously elevated in cord blood of GDM neonates. Liver-X receptor activation in control HPEC by synthetic agonist TO901319, 7-ketocholesterol, or 7β-hydroxycholesterol upregulated ATP-binding cassette transporters (ABC)A1 and ABCG1 expression, accompanied by increased cellular cholesterol efflux. Upregulation of ABCA1 and ABCG1 and increased cholesterol release to apoA-I and HDL (78 ± 17%, 40 ± 9%, respectively) were also observed in GDM versus control HPEC. The LXR antagonist GGPP reversed ABCA1 and ABCG1 upregulation and reduced the increased cholesterol efflux in GDM HPEC. Similar total cellular cholesterol levels were detected in control and GDM HPEC, while GDM enhanced cholesterol biosynthesis along with upregulated 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and sterol O-acyltransferase 1 (SOAT1) mRNA and protein levels. Our results suggest that in GDM cellular cholesterol homeostasis in the fetoplacental endothelium is modulated via LXR activation and helps to maintain its proper functionality.
妊娠期糖尿病（GDM）与过度的氧化应激有关，可能会影响胎盘血管功能。胆固醇稳态对于维持胎-胎盘内皮功能至关重要。我们旨在研究 GDM 是否以及如何影响人胎-胎盘内皮细胞（HPEC）中的胆固醇代谢。从 GDM 或对照受试者的胎儿足月胎盘动脉血管中分离 HPEC。通过 HDCFDA 荧光染料检测细胞活性氧（ROS）。通过气相色谱-质谱分析定量测定氧化固醇。通过实时 PCR 和免疫印迹分别检测参与胆固醇稳态的基因和蛋白质。从 [H]-胆固醇标记的 HPEC 中测定胆固醇外排，并使用 [C]-乙酸作为胆固醇前体来测量胆固醇生物合成和酯化。我们检测到来自 GDM 妊娠的 HPEC 中 ROS 和特定的 ROS 衍生的氧化固醇形成增强。ROS 生成的氧化固醇在 GDM 新生儿的脐血中同时升高。合成激动剂 TO901319、7-酮胆固醇或 7β-羟基胆固醇对对照 HPEC 中的肝 X 受体激活上调 ATP 结合盒转运蛋白（ABC）A1 和 ABCG1 表达，同时伴有细胞胆固醇外排增加。与对照 HPEC 相比，GDM 中的 ABCA1 和 ABCG1 上调以及胆固醇向 apoA-I 和 HDL 的释放增加（分别为 78±17%、40±9%）也观察到。LXR 拮抗剂 GGPP 逆转了 GDM HPEC 中的 ABCA1 和 ABCG1 上调并减少了增加的胆固醇外排。在对照和 GDM HPEC 中检测到相似的总细胞胆固醇水平，而 GDM 增强了胆固醇生物合成，同时上调了 3-羟基-3-甲基戊二酰辅酶 A 还原酶（HMGCR）和固醇 O-酰基转移酶 1（SOAT1）mRNA 和蛋白水平。我们的结果表明，在 GDM 中，胎-胎盘内皮细胞中的细胞胆固醇稳态通过 LXR 激活进行调节，有助于维持其适当的功能。
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