Background:We have demonstrated that protein aggregation plays a pivotal role in the pathophysiology of preeclampsia and identified several aggregated proteins in the circulation of preeclampsia patients, the most prominent of which is the serum protein TTR (transthyretin). However, the mechanisms that underlie protein aggregation remain poorly addressed.Methods:We examined TTR aggregates in hypoxia/reoxygenation-exposed primary human trophoblasts (PHTs) and the preeclampsia placenta using complementary approaches, including a novel protein aggregate detection assay. Mechanistic analysis was performed in hypoxia/reoxygenation-exposed PHTs and Ttr transgenic mice overexpressing transgene-encoded wild-type human TTR or Ttr^−/− mice. High-resolution ultrasound analysis was used to measure placental blood flow in pregnant mice.Results:TTR aggregation was inducible in PHTs and the TCL-1 trophoblast cell line by endoplasmic reticulum stress inducers or autophagy-lysosomal disruptors. PHTs exposed to hypoxia/reoxygenation showed increased intracellular BiP (binding immunoglobulin protein), phosphorylated IRE1α (inositol-requiring enzyme-1α), PDI (protein disulfide isomerase), and Ero-1, all markers of the unfolded protein response, and the apoptosis mediator caspase-3. Blockade of IRE1α inhibited hypoxia/reoxygenation-induced upregulation of Ero-1 in PHTs. Excessive unfolded protein response activation was observed in the early-onset preeclampsia placenta. Importantly, pregnant human TTR mice displayed aggregated TTR in the junctional zone of the placenta and severe preeclampsia-like features. High-resolution ultrasound analysis revealed low blood flow in uterine and umbilical arteries in human TTR mice compared with control mice. However, Ttr^−/− mice did not show any pregnancy-associated abnormalities.Conclusions:These observations in the preeclampsia placenta, cultured trophoblasts, and Ttr transgenic mice indicate that TTR aggregation is an important causal contributor to preeclampsia pathophysiology.

中文翻译：

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来自人胎盘、内质网应激滋养层细胞和转基因小鼠的证据表明运甲状腺素蛋白病与先兆子痫有关

背景：我们已经证明蛋白质聚集在先兆子痫的病理生理学中起着关键作用，并鉴定了先兆子痫患者循环中的几种聚集蛋白，其中最突出的是血清蛋白TTR（甲状腺素运载蛋白）。然而，蛋白质聚集的机制仍然没有得到很好的解决。方法：我们使用补充方法（包括一种新型蛋白质聚集体检测测定法）检查了缺氧/复氧暴露的原代人滋养层细胞（PHT）和先兆子痫胎盘中的 TTR 聚集体。在缺氧/复氧暴露的 PHT 和过度表达转基因编码的野生型人类 TTR 或Ttr ^−/−小鼠的 Ttr 转基因小鼠中进行了机制分析。采用高分辨率超声分析测量妊娠小鼠胎盘血流量。结果：内质网应激诱导剂或自噬-溶酶体干扰剂可诱导 PHT 和 TCL-1 滋养层细胞系中 TTR 聚集。暴露于缺氧/复氧的 PHT 表现出细胞内 BiP（结合免疫球蛋白）、磷酸化 IRE1α（肌醇需要酶 1α）、PDI（蛋白质二硫键异构酶）和 Ero-1 的增加，所有这些都是未折叠蛋白反应的标志物，以及细胞凋亡介质 caspase-3。IRE1α 的阻断可抑制 PHT 中缺氧/复氧诱导的 Ero-1 上调。在早发性先兆子痫胎盘中观察到过度的未折叠蛋白反应激活。重要的是，怀孕的人类 TTR 小鼠在胎盘交界区表现出聚集的 TTR 和严重的先兆子痫样特征。高分辨率超声分析显示，与对照小鼠相比，人类 TTR 小鼠的子宫和脐动脉血流量较低。然而，Ttr ^−/−小鼠没有表现出任何与妊娠相关的异常。结论：在先兆子痫胎盘、培养的滋养层细胞和Ttr转基因小鼠中的这些观察结果表明，TTR聚集是先兆子痫病理生理学的重要因果因素。