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Spontaneous preterm labor is an important complication in perinatology characterized by early onset myometrium contractions leading to labor at preterm. However, the exact mechanism that maintain uterine quiescence and promote increased uterine contractility during labor were incompletely defined. MicroRNAs is a class of short non-coding RNAs that regulate gene expression at the post-transcriptional level by binding the 3' untranslated region of target mRNAs and play an important role in biological process and cellular functions. We hypothesized we could find differentially expressed microRNAs in the myometrium of women in spontaneous preterm labor. Thus, a microarray analysis of miRNAs of preterm myometrium was performed. 18 out of the 2006 detected microRNAs were found to be significantly dysregulated in myometrium in labor verse not in labor at preterm. Biological validation by quantitative real-time polymerase chain reaction confirms us a consistence rate of 83.3% (5 out of 6) with microarray analysis. The target genes for validated microRNAs were predicted by three algorithms (PicTar, TargetScan, and miRanda). Most of the potential targets of the miRNAs were relevant to positive regulation of cardiac muscle hypertrophy, reduction of cytosolic calcium ion concentration and relaxation of cardiac muscle as well as prostate cancer, adherents junction, regulation of actin cytoskeleton and regulation and other factor-regulated calcium reabsorption. Our result illustrates a characteristic microRNA profile in myometrium tissues and provides a new understanding of the process involved in spontaneous preterm labor.

Transformation of the spiral arteries including the displacement of vascular endothelial cells by extravillous trophoblasts is an essential prerequisite to normal placentation. However, the activated endothelial cells resist the invasion of trophoblasts, which contributes to the pathologies of some pregnant disorders. Our previous studies have demonstrated that Cyclosporin A (CsA) promotes the migration and invasion of human first-trimester trophoblasts. In the present study, we further investigated whether CsA could promote the ability of trophoblasts to displace the activated human umbilical vein endothelial cell (HUVEC) monolayers and the possible molecular mechanisms. Human choriocarcinoma Jar cells were used as a model of invasive trophoblasts. CsA pretreated JAR cells (red) were added to HUVEC monolayers (green) activated with either necrotic JAR cells or tumor necrosis factor alpha (TNFα). The ability of JAR cells to displace HUVECs from the monolayers was examined by confocal microscopy. The effects of CsA on Titin and E-cadherin expression, matrix metalloproteinases (MMPs) activity and CXCL12 secretion of JAR cells were evaluated by western blot, gelatin zymography and enzyme-linked immunosorbent assay (ELISA), respectively. We found that CsA pretreatment increased the ability of JAR cells to displace activated HUVECs from the monolayers. However, the displacement was reduced by untreated JAR cells. Moreover, CsA pretreatment up-regulated Titin expression, down-regulated E-cadherin expression, improved MMP2 and MMP9 activity, and increased the CXCL12 secretion in JAR cells. These results indicate that CsA may improve the trophoblast invasion to activated HUVEC monolayers through different downstream targets, and ultimately, improve the transformation and remodeling of spiral arteries.

Previous studies showed that aberrant HLA-G expression in trophoblast cells plays important roles in trophoblast invasion; however, the mechanisms remain to be explored. In this study, we found that suppressed HLA-G expression could dramatically decrease the mRNA and protein expression levels of matrix metalloproteinase 2 and matrix metalloproteinase 9, and in the proteome assay, there were 3 identified proteins namely, prefoldin 1, eukaryotic translation elongation factor 2 and malate dehydrogenase 2, which were verified by Western blot and known to be associated with invasion, cell cycle and cell metabolism, respectively. Collectively, our study indicated a potential involvement of HLA-G in autocrine networks that may regulate prefoldin, MMPs and trophoblast invasion at the maternal-fetal interface in human pregnancy.