Status of p53 in first-trimester cytotrophoblastic cells.

p53 has been called the cellular gatekeeper of the genome because it can induce cell-cycle arrest in G1, apoptosis or affect DNA replication in response to DNA damage. As p53 has been observed in first-trimester cytotrophoblastic cells (CTB), but its expression in normal cells is generally not detectable because of its short half-life, p53 could play an important role in cellular differentiation and/or in the control of the invasion of trophoblastic cells; therefore, p53 status was investigated in these cells. Using different antibodies recognizing different epitopes of p53 protein, abundant p53 expression was observed both in nuclear and in cytoplasmic compartments of first-trimester CTB.

Involvement of MAPK pathway in TNF-alpha-induced MMP-9 expression in human trophoblastic cells.

The aim of this article was to investigate the signalling pathways involved in metalloproteinase-9 (MMP-9) expression induced by tumour necrosis factor-alpha (TNF-alpha) in first-trimester trophoblastic cells. TNF-alpha-induced MMP-9 expression, secretion and activity were completely blocked by stress-activated protein kinase/jun kinase (SAPK/JNK) and Erk inhibitors (SP600 125 and U0126 respectively) but not by p38 mitogen-activated protein kinase (MAPK) inhibitors (SB203 580 and SB202 190). Stimulation of HIPEC 65 cells with TNF-alpha caused phosphorylation of JNK and extracellular signal-regulated kinase 1/2 (Erk1/2), with a peak after 20 min of treatment.

Effect of leukemia inhibitory factor on human cytotrophoblast differentiation along the invasive pathway.

Problem: Leukemia inhibitory factor (LIF) is a pleiotropic secreted cytokine that was shown to be essential for blastocyst implantation in mice. Since it is well documented that LIF is produced by the human endometrium, we wondered if this cytokine was capable of modulating the invasive behaviour of human cytotrophoblastic cells (CTB).

Methods: CTB were isolated and purified from first trimester abortions, separated or not into cells bearing a laminin or a fibronectin receptor (alpha 6 beta 4 or alpha 5 beta 1 respectively) using specific monoclonal antibodies and magnetic particles.

Gelatinase and oncofetal fibronectin secretion is dependent on integrin expression on human cytotrophoblasts.

Collagenolytic activity of cytotrophoblasts is stimulated by glycoproteins of the extracellular matrix and since this stimulation can possibly occur through integrins, we measured the gelatinolytic activity of villous and extravillous cytotrophoblasts according to the type of integrins expressed on these cells. Cytotrophoblasts were isolated from legal abortions, immunopurified with anti-CD45, separated according to their expression of histocompatibility-linked antigen (HLA)-G, alpha 6 or alpha 5 integrin subunits and cultured for 5 days on plastic or agarose. Fetal fibronectin, human chorionic gonadotrophin (HCG) and the gelatinolytic activity were measured in the culture supernatants.

Pregnancy-associated plasma protein-A (PAPP-A) inhibits thrombin-induced coagulation of plasma.

Concentrations of immunoreactive PAPP-A have been found significantly lower in the serum as compared to heparin or EDTA plasma from the same patients. After coagulation significant amounts of PAPP-A remain associated with the clot. Purified PAPP-A inhibits thrombin induced coagulation of plasma.