RNA interference-mediated silencing of laminin receptor 1 (LR1) suppresses migration and invasion and down-regulates matrix metalloproteinase (MMP)-2 and MMP-9 in trophoblast cells: implication in the pathogenesis of preeclampsia

Shallow trophoblast invasion is a common pathological feature of preeclampsia. The 67 kDa laminin receptor 1 (LR1) is a laminin-binding protein that has been reported to be down-regulated in preeclamptic placentas. The aim of the present study was to determine the functional role of LR1 in the migration and invasion of the trophoblast cell line, JEG3 cells. RNA interference mediated by plasmid expressing LR1 short hairpin RNA (shRNA) was utilized to knockdown LR1 expression in JEG3 cells. We found that the mRNA and protein expression levels of LR1 were significantly reduced in LR1-specific shRNA transfected cells compared with the untransfected and control shRNA transfected cells. The wound healing and Transwell invasion assays demonstrated that LR1 knockdown remarkably suppressed the migration and invasion potential of JEG3 cells. The gelatin zymography assay showed that LR1 knockdown greatly reduced matrix metalloproteinase (MMP)-2 and MMP-9 activities in the culture supernatants. Western blot analysis showed that LR1 shRNA significantly decreased expression levels of MMP-2, MMP-9 and phospho-extracellular signal-regulated kinase, but increased expression levels of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in comparison to the control vector-transfected cells. In conclusion, our data support an important role for LR1 in regulating trophoblast invasion and migration, and suggest a possible pathological mechanism of preeclampsia.