Study of the expression and biological activity of matrix metalloproteases and serine proteases involved in the activation pathway of plasminogen at the mouse maternal-fetal interface

CORTINA ME; LITWIN S; MIRANDA S

CABA

Congreso; First French-Argentine Immunology Congress; 2010

SAI-Grupo Rioplatense de Citometría de Flujo-SAP(Inmunología pediatrica)

Repeated pregnancies increase the number of fetal cells in the maternal organism and also induce important changes in the LT subsets of thymus and bone marrow, previously reported by us. We have shown that multiparity status increases the invasive trophoblast tissue (ITT) at maternal-fetal interface in normal and abortive pregnancies. In order to study the local molecular mechanism, we previously detected an enhanced VEGF expression in ITT.  Besides its pro-angiogenic function, VEGF increases the expression of metaloproteases MMP2 and MMP-9 and activates serine proteases involved in the activation pathway of plasminogen (PAI- 1, PAI-2, tPA and uPA). Moreover, plasmin cleaves VEGF bound to extracellular matrix (ECM), activates MMPs and degrades ECM. In this work we studied these proteins in our mouse multiparity model.   CBA/J female mice were divided in three groups: Primiparous Young: 3.0±0.5 months old; Primiparous Old: 8.5±0.5 months old, both with a first pregnancy, and Multiparous Old: 8.5±0.5 months old with 4 pregnancies. Females were mated with BALB/c (normal crossbreeding) or DBA/2 males (abortion crossbreeding). We analyzed the placental expression of plasminogen by Western Blot (WB) and Immunohistochemistry (IHC) and observed a two fold increase in both MO groups compared to primiparous groups (p<0.001). Its expression was restricted to spongiotrophoblast tissue. The expression of PAI-1, PAI-2 and tPA was not modified by multiparity (WB-IHC). In agreement with the increase of plasminogen and VEGF, placental expression of MMP-9 and MMP-2 were increased (WB) only in the normal MO group (p<0.05). However, their activities, according to gelatin zymography studies, remained unchanged, indicating other local mechanisms of control. Multiparity upregulates the placental expression of plasminogen, suggesting that placenta represent a new place of extra-hepatic synthesis and its involvement in the trophoblast invasion process.