MicroRNA expression profiles and networks in placentas complicated with selective intrauterine growth restriction

The microRNA (miRNA) profiles of placentas complicated with selective intrauterine growth restriction (sIUGR) are unknown. In the present study, the sIUGR-associated placental miRNA expression was investigated using microarray and confirmatory reverse transcriptase-quantitative polymerase chain reaction studies. Placenta samples around the individual insertion region for each umbilical cord were collected from monochorionic twins complicated with (n=17) or without sIUGR (control, n=16). miRNA profile analysis was performed on two sIUGR cases and one control using an Affymetrix microRNA 4.0 Array system. A total of 14 miRNAs were identified to be specifically differentially expressed (7 upregulated and 7 downregulated) among larger twins of sIUGR cases compared with smaller twins of sIUGR cases. The target genes of the identified miRNAs participate in organ size, cell differentiation, cell proliferation and migration. In addition, according to the miRNA-pathway network analysis, key miRNAs and pathways (transforming growth factor-β, mitogen-activated protein kinase and Wnt) were identified to be associated with the pathogenesis of sIUGR. To the best of our knowledge, the results of the current study have provided the most complete miRNA profiles and the most detailed miRNA regulatory networks of placental tissues complicated with sIUGR.