FIGURE 5.

miR-377 and let-7a negatively regulate trophoblast proliferation. Pre-miR precursors for miR-377, let-7a, and miR-145 or a pre-miR control (PreC) were transfected into first trimester placental explants (n = 6). The level of miR expression, quantified by qPCR, was significantly increased 24 h post-transfection (A–C). Cytotrophoblast proliferation, determined by counting the number of Ki67-positive cytotrophoblasts (D and E) or BrdU-positive cytotrophoblasts (F) in relation to total cytotrophoblast at 48 h post-transfection was reduced following overexpression of miR-377 and let-7a but not miR-145. D, arrows indicate cytotrophoblasts (CT) and syncytiotrophoblast (ST). One-way analysis of variance with planned contrasts was used to assess differences between sample groups; p < 0.05 was considered significant. Scale bars, 50 μm.