PDF(Pubmed)
Abstract：
Preeclampsia (PE) is a life-threatening pregnancy-specific complication with controversial mechanisms and no effective treatment except delivery is available. Currently, increasing researchers suggested that PE shares pathophysiologic features with protein misfolding/aggregation disorders, such as Alzheimer disease (AD). Evidences have proposed defective autophagy as a potential source of protein aggregation in PE. Endoplasmic reticulum-selective autophagy (ER-phagy) plays a critical role in clearing misfolded proteins and maintaining ER homeostasis. However, its roles in the molecular pathology of PE remain unclear. We found that lncRNA DUXAP8 was upregulated in preeclamptic placentae and significantly correlated with clinical indicators. DUXAP8 specifically binds to PCBP2 and inhibits its ubiquitination-mediated degradation, and decreased levels of PCBP2 reversed the activation effect of DUXAP8 overexpression on AKT/mTOR signaling pathway. Function experiments showed that DUXAP8 overexpression inhibited trophoblastic proliferation, migration, and invasion of HTR-8/SVneo and JAR cells. Moreover, pathological accumulation of swollen and lytic ER (endoplasmic reticulum) was observed in DUXAP8-overexpressed HTR8/SVneo cells and PE placental villus trophoblast cells, which suggesting that ER clearance ability is impaired. Further studies found that DUXAP8 overexpression impaired ER-phagy and caused protein aggregation medicated by reduced FAM134B and LC3II expression (key proteins involved in ER-phagy) via activating AKT/mTOR signaling pathway. The increased level of FAM134B significantly reversed the inhibitory effect of DUXAP8 overexpression on the proliferation, migration, and invasion of trophoblasts. In vivo, DUXAP8 overexpression through tail vein injection of adenovirus induced PE-like phenotypes in pregnant rats accompanied with activated AKT/mTOR signaling, decreased expression of FAM134B and LC3-II proteins and increased protein aggregation in placental tissues. Our study reveals the important role of lncRNA DUXAP8 in regulating trophoblast biological behaviors through FAM134B-mediated ER-phagy, providing a new theoretical basis for understanding the pathogenesis of PE.
摘要：
先兆子痫（PE）是一种威胁生命的妊娠特异性并发症，具有有争议的机制，除分娩外尚无有效的治疗方法。目前,越来越多的研究人员认为，PE与蛋白质错误折叠/聚集障碍具有共同的病理生理学特征，例如阿尔茨海默病(AD)。有证据表明，有缺陷的自噬是PE中蛋白质聚集的潜在来源。内质网选择性自噬（ER-phagy）在清除错误折叠的蛋白质和维持ER稳态中起关键作用。然而,其在PE的分子病理学中的作用尚不清楚。我们发现lncRNADUXAP8在先兆子痫胎盘中上调，并与临床指标显着相关。DUXAP8特异性结合PCBP2并抑制其泛素化介导的降解，PCBP2水平的降低逆转了DUXAP8过表达对AKT/mTOR信号通路的激活作用。功能实验表明,DUXAP8过表达抑制滋养细胞增殖,迁移,以及HTR-8/SVneo和JAR细胞的侵袭。此外，在DUXAP8过表达的HTR8/SVneo细胞和PE胎盘绒毛滋养层细胞中观察到肿胀和溶解ER（内质网）的病理积累，这表明ER清除能力受损。进一步的研究发现，DUXAP8过表达通过激活AKT/mTOR信号通路降低FAM134B和LC3II（参与ER-phagy的关键蛋白）表达，从而损害ER-phagy并引起蛋白聚集。FAM134B水平的升高显著逆转了DUXAP8过表达对细胞增殖的抑制作用,迁移,和滋养层的入侵。在体内,通过尾静脉注射DUXAP8过表达腺病毒在妊娠大鼠中诱导的PE样表型，并伴有激活的AKT/mTOR信号，胎盘组织中FAM134B和LC3-II蛋白表达降低，蛋白聚集增加。我们的研究揭示了lncRNADUXAP8在通过FAM134B介导的ER-吞噬调节滋养细胞生物学行为中的重要作用。为认识PE的发病机制提供了新的理论依据。
