Potential for miRNAs as Biomarkers and Therapeutic Targets in Preeclampsia

Impact of ferroptosis on preeclampsia: A review

Preeclampsia (PE) is usually associated with the accumulation of reactive oxygen species (ROS) resulting from heightened oxidative stress (OS). Ferroptosis is a unique type of lipid peroxidation-induced iron-dependent cell death distinct from traditional apoptosis, necroptosis, and pyroptosis and most likely contributes considerable to PE pathogenesis. At approximately 10-12 weeks of gestation, trophoblasts create an environment rich in oxygen and iron. In patients with PE, ferroptosis-related genes such as HIF1 and MAPK8 are downregulated, whereas PLIN2 is upregulated. Furthermore, miR-30b-5p overexpression inhibits solute carrier family 11 member 2, resulting in a decrease in glutathione levels and an increase in the labile iron pool. At the maternal-fetal interface, physiological hypoxia/reperfusion and excessive iron result in lipid peroxidation and ROS production. Owing to the high expression of Fpn and polyunsaturated fatty acid-containing phospholipid-related enzymes, including acyl-CoA synthetase long-chain family member 4, lysophosphatidylcholine acyl-transferase 3, and spermidine/spermine N1-acetyltransferase 1, trophoblasts become more susceptible to OS and ROS damage. In stage 1, the injured trophoblasts exhibit poor invasion and incomplete uterine spiral artery remodeling caused by ferroptosis, leading to placental ischemia and hypoxia. Subsequently, ferroptosis marked by OS occurs in stage 2, eventually causing PE. We aimed to explore the new therapeutic target of PE through OS in ferroptosis.

MiR-133b regulates oxidative stress injury of trophoblasts in preeclampsia by mediating the JAK2/STAT3 signaling pathway

Preeclampsia (PE) is a pregnancy-related syndrome. Aberrant placental microRNAs (miRNAs) expression might associate with PE, including miR-133b. However, its role in the pathogenesis of preeclampsia remains elusive. Therefore, this study explored the role of miR-133b in oxidative stress injury of trophoblasts in preeclampsia (PE) by mediating the JAK2/STAT3 signaling pathway. Placental tissues were collected from PE patients to detect the expression of miR-133b and JAK2/STAT3. Then, in vitro experiments were performed on human extravillous trophoblast-derived HTR-8/SVneo cells, which were divided into Normal, hypoxia/reoxygenation (H/R), H/R + miR-NC, H/R + miR-133b inhibitor, H/R + JAK2 siRNA and H/R + miR-133b inhibitor + JAK2 siRNA groups. Cell invasion and migration abilities were detected by Transwell and wound healing assays, while apoptosis was detected by flow cytometry. The intracellular oxidative stress levels were also measured. Furthermore, the expression of miR-133b and the JAK2/STAT3 pathway was determined by qRT-PCR and Western blotting. We found that miR-133b was up-regulated, with decreases in JAK2 and p-STAT3/STAT3 in placental tissues of PE patients. Additionally, HTR8/SVneo cells in the H/R group had decreased invasion and migration abilities with increased apoptotic rates and oxidative stress levels. Moreover, the expression of miR-133b was up-regulated with decreases in p-JAK2 and p-STAT3 in H/R-treated HTR8/SVneo cells. These indicators in the H/R + miR-133b inhibitor group were ameliorated in comparison with those in the H/R group but deteriorated in the H/R + JAK2 siRNA group. Moreover, JAK2 siRNA reversed the positive effect of the miR-133b inhibitor on the invasion and migration abilities of trophoblasts. In summary, inhibiting miR-133b may improve oxidative stress injury to promote the migration and invasion of trophoblasts and suppress apoptosis by activating the JAK2/STAT3 pathway.

Overexpression of let-7d explains down-regulated KDM3A and ENO2 in the pathogenesis of preeclampsia

Pre‐eclampsia (PE) is the leading cause of maternal death; however, the causative molecular basis remains largely unknown. Recent studies have revealed the important role microRNAs (miRNAs) play in PE. We aimed to explore the effects of let‐7d on trophoblast proliferation, migration, invasion and apoptosis in PE and its underlying mechanism. Placental tissues were collected from PE patients and healthy pregnant women, and it was found that let‐7d expression was increased, while KDM3A and ENO2 expression was decreased in PE tissues and cells. Bioinformatics analysis indicated the interaction among let‐7d, KDM3A and ENO2, confirmed by dual luciferase reporter gene assay; ChIP experiment identified methylated modification to ENO2 by KDM3A. With gain‐ and loss‐function method, silencing of let‐7d increased KDM3A expression and enhanced the binding between KDM3A and ENO2. Furthermore, overexpression of let‐7d suppressed cell proliferation, migration and invasion of trophoblasts, and induced apoptosis of trophoblasts, while these capacities were restored upon additional treatment of overexpressed ENO2. PE rat models were established to explore the effects of let‐7d and ENO2 on PE in vivo. The results established that the silencing of let‐7d alleviated the tissue injury and PE‐related symptoms when reducing urine protein, TUNEL‐positive cells and increasing ENO2, and KDM3A expression in rats. Cumulatively, let‐7d suppressed cell progression of trophoblasts, and induced apoptosis through the down‐regulation of KDM3A to promote ENO2 methylation, thereby promoting progression of PE. Such an epigenetic network of let‐7d, KDM3A and ENO2 in the pathogenesis of PE might provide novel insight into targeted therapy against this disorder.

Elevated microRNA-125b inhibits cytotrophoblast invasion and impairs endothelial cell function in preeclampsia

Preeclampsia (PE) is a life-threatening disorder of human pregnancy affecting 5-8% of all pregnancies. Currently, PE remains an elusive complicated and heterogenous medical condition with no early marker or symptoms is recognized for this serious pregnancy complications. Here, we profiled the plasma miRNA expression patterns associated with preeclampsia and found 16 miRNAs were deregulated (p < 0.01) in patients who later developed PE. Circulating hsa-miR-125b was aberrantly upregulated in early pregnancy and significantly reduced after delivery in preeclampsia. We then investigated the underlying molecular mechanisms between miR-125b and PE in vitro. We found that upregulated miR-125b can target KCNA1 to inhibit trophoblast invasion in human trophoblast cells. Moreover, overexpression of miR-125b in HUVECs impaired endothelial cell function through GPC1. The findings indicated that upregulated miR-125b leads to impaired placentation, and an increased risk of preeclampsia, Our studies provide novel insights into the underlying mechanisms on the association of miR-125b in early pregnancy and risk of PE, miR-125b might be a more specific predictive marker and a safe therapeutic target for treating patients with PE.

miR-30-5p-mediated ferroptosis of trophoblasts is implicated in the pathogenesis of preeclampsia

Oxidative stress is a major cause of adverse outcomes in preeclampsia (PE). Ferroptosis, i.e. programmed cell death from iron-dependent lipid peroxidation, likely mediates PE pathogenesis. We evaluated specific markers for ferroptosis in normal and PE placental tissues, using in vitro (trophoblasts) and in vivo (rat) models. Increase in malondialdehyde content and total Fe²⁺ along with reduced the glutathione content and glutathione peroxidase activity was observed in PE placenta. While the trophoblasts experienced death under hypoxia, inhibitors of ferroptosis, apoptosis, autophagy, and necrosis increased the cell viability. Microarrays, bioinformatic analysis, and luciferase reporter assay revealed that upregulation of miR-30b-5p in PE models plays a pivotal role in ferroptosis, by downregulating Cys2/glutamate antiporter and PAX3 and decreasing ferroportin 1 (an iron exporter) expression, resulting in decreased GSH and increased labile Fe²⁺. Inhibition of miR-30b-5p expression and supplementation with ferroptosis inhibitors attenuated the PE symptoms in rat models, making miR-30b-5p a potential therapeutic target for PE.