MicroRNA221 is Involved in Human Placental Development by Targeting DDIT4.

Abstract

miR221 might have an important role in human embryo development. However, little is known about the function of miR221 in the human embryo. The aim of this study was to evaluate miR221 expression in human placental tissue, and to analyze the relationship between miR221 and target genes. The human placentas tissue samples were collected from healthy pregnant women who were willing to terminate their pregnancy. The total RNA isolation and microRNA reverse transcription quantification were performed by TaqMan microRNA assay and qRT-PCR. The results showed that miR221 expression was significantly higher in 55- to 71-day placenta (mean value=0.1049) than that in 38- to 54- day (the mean value=0.0133) (p<0.001). miR221 targeting genes, such as PIK3R1, CDKN1B, CDKN1C, DDIT4, and FOS, were detected in human placenta tissue, but only DDIT4 was significantly decreased with development (mean value: 0.0101 for 38∼54 days, 0.0021 for 55∼71 days, p<0.001). Further analysis showed that only DDIT4 was negatively correlated with miR221 expression (DDIT4: r=-0.396, p=0.033; PI3KR: r=0.322, p=0.089; CDKN1B: r=0.298, p=0.128; CDKN1C: r=0.198, p=0.304; FOS: r=0.171, p=0.347). These findings indicate that miR221 might play an important role in human placental development by precisely regulating the DDIT4 expression.