Upregulation of miRNA-26a Enhances the Apoptosis of Cerebral Neurons by Targeting EphA2 and Inhibiting the MAPK Pathway.

Neural tube defects (NTDs) constitute the second most common congenital malformation of the central nervous system. The pathogenesis of NTDs is not entirely clear. In recent years, microRNAs (miRNAs) have become a hot spot in genetic and developmental biology research. The present study aimed to explore the potential role of miRNA-26a in NTDs and the underlying pathogenesis thereof. First, we found significantly increased miRNA-26a expression in fetuses with NTDs (p < 0.0001), which significantly downregulated EphA2 and ERK1 mRNA and protein expression levels in fetuses with NTDs compared to normal controls (p < 0.01). In addition, a dual-luciferase reporter assay showed that miR-26a negatively regulated EphA2 by directly binding with the 3'-untranslated region of EphA2. Second, the upregulation of miRNA-26a expression increased caspase 3 and 9 protein expression levels (p < 0.01) and decreased EphA2 mRNA and protein expression levels (p < 0.01), as well as ERK1 and SRF protein expression levels (p < 0.01) in mouse neural stem cells (NE-4C) and human astroblastoma cells (U87MG). Furthermore, the upregulation of miRNA-26a inhibited cell proliferation and enhanced apoptosis of NE-4C and U87MG cells (p < 0.05). Similar results were observed with the MAPK inhibitor PD98059 (p < 0.01). These results suggest that miR-26a targets EphA2, modulates phosphorylation of the MAPK/ERK (MEK) pathway, regulates SRF, and participates in regulating nervous cell proliferation and apoptosis. Dysregulation of the aforementioned mechanism may be involved in the pathogenesis of NTDs.

Comparative proteome analysis of amniotic fluids and placentas from patients with idiopathic polyhydramnios.

INTRODUCTION: Idiopathic polyhydramnios (IPH) is an abnormal increase in amniotic fluid volume (AFV). This condition has unknown etiologies and is associated with various adverse pregnancy outcomes including maternal and fetal complication. This study aims to establish a comparative proteome profile for the human amniotic fluid (AF) of IPH and normal pregnancies and identify the responsible mediators and pathways that regulate AFV. METHODS: We first employed coupled isobaric tags for relative and absolute quantitation (iTRAQ) proteomics and bioinformatics analysis to examine the differentially expression proteins (DEPs) in the AF of IPH and normal pregnancies. Second, CUL5, HIP1, FSTL3, and LAMP2 proteins were selected for verification in amnion, chorion, and placental tissues by Western blot analysis. RESULTS: We identified 357 DEPs with 282 upregulated and 75 downregulated. Bioinformatics analysis revealed that cell, cellular process, and binding were the most enriched Gene Ontology terms. Amoebiasis, hematopoietic cell lineage, and NF-kappa B signaling pathway were the top significant pathways. In the verification procedure, FSTL3 protein had a highly significant expression in the amnion, chorion, and placentas of IPH and normal AFV groups (p < 0.05). DISCUSSION: Our results provide new insights into idiopathic polyhydramnios and offer fundamental points for future studies on AFV.