Preterm labor (PTL) is one of the obstetric complications, and is known to be associated with abnormal maternal inflammatory response and intrauterine inflammation and/or infection. However, the expression of specific miRNAs associated with PTL is not clear. In this study, we performed combination analysis of miRNA array and gene array, and then selected one miRNA (miR-373-3p) and its putative target genes (CD44 and RDX) that exhibited large expression differences in term and PTL placentas with or without inflammation. Using qRT-PCR and luciferase assays, we confirmed that miR-373-3p directly targeted CD44 and RDX. Overexpression of miR-373-3p reduced the migration and invasion of trophoblast cells, while inhibition of miR-373-3p restored the migration and invasion abilities of trophoblast cells. Finally, we validated the expression of miR-373-3p and its target genes in clinical patients' blood. miR-373-3p was increased in PTL patients' blood, and was the most expressed in PTL patients' blood with inflammation. In addition, by targeting the miR-373-3p, CD44 and RDX was decreased in PTL patients' blood, and their expression were the lowest in PTL patients' blood with inflammation. Taken together, these findings suggest that miR-373-3p and its target genes can be potential biomarkers for diagnosis of PTL.
Keywords: CD44; invasion; miR-373-3p; preterm labor; radixin; trophoblast cells.