Fig. 2.

miR-200b/429 are up-regulated and ZEB1 and ZEB2 are down-regulated in two models of preterm labor. Diagram of RU486 treatment (A) or LPS treatment (B) to induce preterm labor. Animals were injected with a single s.c. injection of RU486 (200 μg) or intraamniotic injections of 1.5 μg of LPS into each sac at 15.5 dpc. IL, laboring myometrium; NIL, nonlaboring control. Mice were considered in labor on birth of one pup. miR-200b/429 are significantly up-regulated in RU486-induced (C) and LPS-induced (D) preterm labor. mmu, Mus musculus. ZEB1 and ZEB2 mRNA levels in the same tissue samples as in C and D are decreased with RU486-induced (E) or LPS-induced (F) preterm labor. Expression of each miRNA/mRNA was determined by qRT-PCR, normalized to U6/GAPDH, and expressed as the fold change over vehicle-treated controls. Mean ± SEM values are shown (Student’s t test, *P < 0.05, **P < 0.01; n = 7 per group). Experiments were repeated twice with similar results. ZEB1 protein expression in nuclear extracts of murine myometrium is decreased in association with RU486-induced (G) or LPS-induced (H) preterm labor. β-actin was used as a loading control. Densitometry analysis of blots comparing uterine nuclear extracts from RU486- and LPS-treated mice with vehicle-injected controls revealed a significant reduction in ZEB1 protein with preterm labor (Student’s t test, *P < 0.05; n = 7 mice per group).