RNA interference-mediated knockdown of Notch-1 inhibits migration and invasion, down-regulates matrix metalloproteinases and suppresses NF-κB signaling pathway in trophoblast cells

Preeclampsia is well known to present with reduced trophoblast invasion into the placental bed. Notch-1, a ligand-activated transmembrane receptor, has been reported to be down-regulated in preeclamptic human placentas. This study was conducted to explore the role of Notch-1 in the cell migration and invasion of a human trophoblast cell line, JEG3 cells. Short hairpin RNA (shRNA)-mediated RNA interference was performed to effectively suppress the endogenous expression of Notch-1 at both mRNA and protein levels in JEG3 cells. Results of wound healing and transwell assays showed that knockdown of Notch-1 reduced trophoblast cell migration and invasion. The protein expressions and activities of matrix metalloproteinase (MMP)-2 and MMP-9 were reduced in JEG3 cell when Notch-1 was decreased. Furthermore, the epithelial-cadherin (E-cadherin) expression increased in JEG3 cells when Notch-1 was inhibited, whereas its suppressor Snail decreased in these cells. Moreover, knockdown of Notch-1 also suppressed NF-κB signaling pathway by inhibiting the phosphorylation of nuclear factor kappa B (NF-κB p65) inhibitor (IκBα) and the subsequent nuclear translocation of NF-κB subunit p65 in JEG3 cells. In summary, we demonstrate that Notch-1 contributes to trophoblast cell migration and invasion and that it may be involved in the pathology of human preeclampsia.