Fig. 6. Kisspeptin-10 inhibits migration and gelatinolytic activity, but not proliferation of isolated first trimester human trophoblasts. (A) Microscopic image of the abluminal side of collagen I (Col I)- or fibronectin (FN)-coated membranes after 48 hours during which isolated FT trophoblasts (1x10⁵ per filter, week 6-9 of gestation) migrated across the membrane in the absence or presence of 0.5 µM Kp-10. (B) Bars on left: Addition of Kp-10 (0.5 µM, black bars) reduced the number of cells that migrated through the filter pores. Results are expressed as mean±s.e.m. (n=3 different trophoblast isolations) of cell migration relative to unstimulated cells set as 1 (white bars) (^*P<0.05 vs control). Bars on right: To assess cell proliferation, 7x10⁴ freshly isolated FT trophoblasts were plated on collagen I in the absence (white bar) or presence of Kp-10 (black bars) added at the time of seeding. Cell numbers were counted after 48 hours. Results are presented as cell number (mean±s.e.m.; n=3) expressed relative to control (=100%). Kp-10 did not affect FT trophoblast proliferation significantly. ns, not significant vs control. (C) Conditioned medium from isolated FT trophoblasts plated on collagen I for 24 or 48 hours was subjected to gelatin zymography. Proteolytic activity was noted for the 72-kDa collagenase corresponding to pro-MMP-2. Protein molceular weight markers are indicated on the right. (D) Addition of Kp-10 suppressed 72-kDa collagenase (MMP-2) activity (^*P<0.01 vs control).