Pregnancy

Matrix Metalloproteinase 9 (MMP9) Expression in Preeclamptic Decidua and MMP9 Induction by Tumor Necrosis Factor Alpha and Interleukin 1 Beta in Human First Trimester Decidual Cells

Abstract
Extravillous trophoblasts (EVTs) invade human decidua via sequential integrin-mediated binding and proteolysis of basement membrane (BM) proteins in the extracellular matrix (ECM). In preeclampsia, shallow EVT invasion impairs spiral artery and arteriole remodeling to reduce utero-placental blood flow. Excess decidual cell-expressed matrix metalloproteinase (MMP) 2 and 9 in response to preeclampsia-related interleukin 1 beta (IL1B) and tumor necrosis factor alpha (TNF) may inappropriately degrade these BM proteins and impede EVT invasion. This study found significantly higher immunohistochemical MMP9 levels in decidual cells and adjacent interstitial trophoblasts in placental sections of preeclamptic versus gestational-age matched control women. In contrast, immunostaining for MMP2 and Tissue Inhibitor of Matrix Metalloproteinases (TIMP1 and TIMP2) were similar in preeclamptic and control groups. First trimester decidual cells were incubated with estradiol (E2) or E2 + medroxyprogesterone acetate (MPA), ± TNF or IL1B. As measured by ELISA, both cytokines elicited concentration-dependent increases in secreted MMP9 levels that were unaffected by MPA. In contrast, secreted levels of MMP2, TIMP1 and TIMP2 were unchanged in all treatment groups. Substrate gel zymography and Western blotting confirmed that each cytokine increased secreted levels MMP9 but not MMP2. Similarly, quantitative RT-PCR found that TNF and IL1B enhanced MMP9, but not MMP2, mRNA levels. At the implantation site, inflammatory cytokine-enhanced MMP9 may promote preeclampsia by disrupting the decidual ECM to interfere with normal stepwise EVT invasion.

Key words: Pregnancy • Cytokines • Decidua • extracellular matrix • matrix metalloproteinase