Relaxin Induces Matrix Metalloproteinase‐9 through Activation of Nuclear Factor Kappa B in Human THP‐1 Cells

Matrix metalloproteinase (MMP) and relaxin are important for tissue remodeling and wound repair. Macrophages populate wound sites and secrete MMPs. Nuclear factor kappa B (NF-kappaB) is linked to MMP gene regulation. Thus, a monocyte/macrophage cell line, THP-1, was used to study the mechanism of relaxin's action on MMPs. Relaxin increased MMP-9 protein and activity in THP-1 cell-conditioned media, with no significant change in MMP-2 activity. NF-kappaB DNA binding activity was elevated in response to relaxin, and supershift assay showed activation of both NF-kappaB subunits p50 and p65. Relaxin also reduced NF-kappaB inhibitor protein, IkappaB-alpha. In conclusion, these data suggest that relaxin-induced MMP-9 expression in THP-1 cells involves NF-kappaB activation.