BackgroundEnhancer RNAs (eRNAs) are a group of lncRNAs transcribed from enhancers, whose regulatory effects on gene expression are an emerging area of interest. However, the role of eRNAs in regulating trophoblast cells and unexplained recurrent pregnancy loss (URPL) remains elusive.MethodsWe profiled eRNAs in villi from URPL patients and matched controls by RNA-seq. Functions of URPL-related eRNAs were further investigated in vitro.ResultsWe identified lnc-SLC4A1-1, which was transcribed from an active enhancer marked with H3K27ac and H3K4me1 and so-called eRNA, highly expressed in URPL patients. Gain-of-function experiments indicated that lnc-SLC4A1-1 facilitated trophoblast cell migration and apoptosis. Mechanistically, as an eRNA, lnc-SLC4A1-1 was retained in the nuclei and recruited transcription factor NF-κB to bind to CXCL8, resulting in increased H3K27ac in the CXCL8 promoter and subsequent elevation of CXCL8 expression. Activation of CXCL8 exacerbated inflammatory reactions in trophoblast cells by inducing TNF-α and IL-1β, which could be blocked by an antagonist of lnc-SLC4A1-1.InterpretationThese findings indicate that an eRNA, lnc-SLC4A1-1, alters trophoblast function via activation of immune responses and by regulating the NF-κB/CXCL8 axis. Our study provides new insights in understanding lncRNA/eRNA function in pathological pregnancy, potentially informing on therapeutic strategies for URPL.FundNational Natural Science Foundation of China, Natural Science Foundation of Jiangsu Province, National Key Research and Development Program, the Priority Academic Program for the Development of Jiangsu Higher Education Institutions.

Mitochondria-related microRNAs (miRNAs) have recently emerged as key regulators of cell metabolism and can modulate mitochondrial fusion and division. In order to investigate the roles of mitochondria-related miRNAs played in obesity, we conducted comprehensive molecular analysis in vitro and in vivo. Based on high-fat-diet (HFD) induced obese mice, we found that hepatic mitochondrial function was markedly altered. Subsequently, we evaluated the expression levels of selected mitochondria-related miRNAs and found that miR-141-3p was up-regulated strikingly in HFD mice. To further verify the role of miR-141-3p in obesity, we carried out gain-and-loss-of-function study in human HepG2 cells. We found that miR-141-3p could modulate ATP production and induce oxidative stress. Through luciferase report gene assay, we identified that phosphatase and tensin homolog (PTEN) was a target of miR-141-3p. Inhibiting PTEN could alter the mitochondrial function, too. Our study suggested that mitochondria-related miR-141-3p induced mitochondrial dysfunction by inhibiting PTEN.

Background Aberrant DNA methylation is considered to be a potential cause of recurrent pregnancy loss (RPL), while potential mechanism has not yet been elucidated. Methods In order to uncover the contribution of the perturbation of DNA methylation in RPL, we performed genome-wide DNA methylation analysis combined with genome-wide gene expression in decidua tissue. Findings Totally, 539 differentially methylated regions (DMRs) were identified and significantly correlated with gene expressions. We observed that hypo-methylated DMR near CREB5 recruited transcription factors binding, such as P53 and SP1, and in turn upregulated CREB5. Compromised cell migration and apoptosis were observed in human CREB5 overexpression trophoblast cell lines, indicating dysfunctional trophoblast cells might contribute to RPL after hypo-methylation of CREB5 . In addition, overexpression of CREB5 altered cell cycle. Interpretation Our data highlights a role of CREB5 involved in the pathogenesis of RPL, and CREB5 maybe a potential diagnostic biomarker for RPL.

Long noncoding RNAs (lncRNAs) have been reported to be involved in various human diseases, and increasing studies have revealed that lncRNAs can play a vital role in preeclampsia (PE). In our study, lncRNA hypoxia-inducible factor 1 alpha (HIF1A) antisense RNA 2 (HIF1A-AS2) was found to be significantly downregulated in placenta tissues of PE patients by quantitative real-time PCR analysis. Moreover, Cell Counting Kit-8 (CCK-8) assays showed that downregulation of HIF1A-AS2 can impede cell proliferation of HTR-8/SVneo and JAR trophoblasts cells. Ectopic overexpression of HIF1A-AS2 can increase the function of trophoblasts cell migration and invasion in vitro . RNA-sequencing (RNA-seq), RNA immunoprecipitation (RIP), and chromatin immunoprecipitation (ChIP) experiments showed that HIF1A-AS2 can recruit lysine-specific demethylase 1 (LSD1) and epigenetically repress pleckstrin homology-like domain, family A, member 1 (PHLDA1) transcription in human trophoblasts cells. In summary, our findings suggest that downregulated HIF1A-AS2 may play a role in the pathogenesis and progression of PE, and has potential as a novel prognostic marker in PE.

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