Pre-eclampsia (PE), which results from abnormal placentation, is a primary cause of maternal and neonatal morbidity and mortality. However, the causes of abnormal development of the placenta remain poorly understood. BHLHE40 is a transcriptional repressor in response to hypoxia. Bioinformatics analysis demonstrated that BHLHE40 negatively regulates miR-196a-5p expression, which may decrease miR-196a-5p to target SNX16. Since SNX16 exerts an inhibitory effect on cell migration, it may disrupt trophoblast cell migration in placentation. Therefore, the objective of this study was to explore a possible role of the BHLHE40/miR-196a-5p/SNX16 axis in PE pathogenesis. BHLHE40, miR-196a-5p and SNX16 mRNA and/or protein levels were detected in PE and normal placenta tissues. PE models in vitro and in vivo were constructed by culturing trophoblasts under hypoxia and reducing the uterine perfusion pressure in pregnant C57/BL6N mice, respectively. BHLHE40 and SNX16 were upregulated in PE placenta, while miR-196a-5p was downregulated. Knockdown of BHLHE40 reversed miR-196a-5p expression in trophoblasts under hypoxia, and upregulation of miR-196a-5p inhibited SNX16 expression. As indicated by ChIP assay, BHLHE40 bound to the promoter of the miR-196a-5p gene; luciferase reporter analysis showed that miR-196a-5p could bind to the 3ʹ-untranslated region of SNX16 mRNA. Knockdown of either BHLHE40 or SNX16, or an increase in miR-196a-5p, restored cell viability, migration, invasion and matrix metalloprotein (MMP)-2 and MMP-9 expression under hypoxia. BHLHE40 knockdown also alleviated PE symptoms in pregnant C57/BL6N mice. This study supports involvement of the BHLHE40/miR-196a-5p/SNX16 axis in PE pathogenesis; Proper adjustment of the BHLHE40/miR-196a-5p/SNX16 axis is able to attenuate PE symptoms.

中文翻译：

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BHLHE40 通过抑制 miR-196a-5p 的转录上调 SNX16，在先兆子痫中发挥病理作用。

先兆子痫 (PE) 由异常胎盘引起，是孕产妇和新生儿发病率和死亡率的主要原因。然而，胎盘异常发育的原因仍然知之甚少。BHLHE40 是一种响应缺氧的转录抑制因子。生物信息学分析表明，BHLHE40 负向调节 miR-196a-5p 的表达，这可能会降低 miR-196a-5p 对 SNX16 的靶向作用。由于 SNX16 对细胞迁移有抑制作用，它可能会破坏胎盘中滋养层细胞的迁移。因此，本研究的目的是探索 BHLHE40/miR-196a-5p/SNX16 轴在 PE 发病机制中的可能作用。在 PE 和正常胎盘组织中检测到 BHLHE40、miR-196a-5p 和 SNX16 mRNA 和/或蛋白质水平。体外和体内PE 模型分别通过在缺氧条件下培养滋养层细胞和降低怀孕 C57/BL6N 小鼠的子宫灌注压来构建。BHLHE40 和 SNX16 在 PE 胎盘中上调，而 miR-196a-5p 下调。BHLHE40 的敲低逆转了缺氧条件下滋养细胞中 miR-196a-5p 的表达，并且 miR-196a-5p 的上调抑制了 SNX16 的表达。ChIP 分析表明，BHLHE40 与 miR-196a-5p 基因的启动子结合；荧光素酶报告基因分析表明，miR-196a-5p 可以与SNX16的 3ʹ-非翻译区结合mRNA。BHLHE40 或 SNX16 的敲低，或 miR-196a-5p 的增加，在缺氧条件下恢复细胞活力、迁移、侵袭和基质金属蛋白 (MMP)-2 和 MMP-9 表达。BHLHE40 敲低还减轻了怀孕的 C57/BL6N 小鼠的 PE 症状。本研究支持 BHLHE40/miR-196a-5p/SNX16 轴参与 PE 发病机制；BHLHE40/miR-196a-5p/SNX16 轴的适当调整能够减轻 PE 症状。