MMP-9 activation mediated by E2 modulates occludin.

(A) Immunoblot of occludin down-regulation by G1, reversed by ONO-4817 (ONO). Protein expression relative to GAPDH was quantitated in a SyngeneG:box (right). (B) Immunoblot of full-length and truncated forms of occludin in Huh7.5 cells treated with G1 and ONO-4817 and the percentage of occludin forms were calculated relative to GAPDH protein levels (values below each band). (C) Schematic representation of occludin (504 amino acids). (D) Immunoblot of pro-MMP-9 (92 KDa) and active MMP-9 (~64 KDa) in Huh7.5 cell membranes and conditioned media (extracellular) following E2 treatment. (E) Immunoblot of MMP-9 in supernatant (extracellular) after siRNA transfection and E2 treatment (0, 1, 100, 10,000 nM). Cleaved occludin (38 KDa) is shown and GAPDH is shown as a gel loading control.