Construction and validation of a placental tissue microarray from specimens of well-documented preeclampsia patients

Immunohistochemical expression of BCL-2 in hydatidiform moles: a tissue microarray study

Background

Hydatidiform moles (HM) are members of gestational trophoblastic diseases (GTD) and, in some cases, might progress to gestational trophoblastic neoplasia (GTN). HMs are either partial (PHM) or complete (CHM). Some HMs are challenging in arriving at a precise histopathological diagnosis. This study aims to investigate the expression of BCL-2 by immunohistochemistry (IHC) in HMs as well as in normal trophoblastic tissues "products of conception (POC) and placentas" using Tissue MicroArray (TMA) technique.

Methods

TMAs were constructed using the archival material of 237 HMs (95 PHM and 142 CHM) and 202 control normal trophoblastic tissues; POC and unremarkable placentas. Sections were immunohistochemically stained using antibodies against BCL-2. The staining was assessed semi-quantatively (intensity and percentage of the positive cells) in different cellular components (trophoblasts and stromal cells).

Results

BCL-2 showed cytoplasmic expression in more than 95% of trophoblasts of PHM, CHM and controls. The staining showed a significant reduction of the intensity from controls (73.7%), PHMs (76.3%) to CHM (26.9%). There was a statistically significant difference between PHM and CHM in the intensity (p-value 0.0005) and the overall scores (p-value 0.0005), but not the percentage score (p-value > 0.05). No significant difference was observed in the positivity of the villous stromal cells between the different groups. All cellular components were visible using the TMA model of two spots/case (3 mm diameter, each) in more than 90% of cases.

Conclusions

Decreased BCL-2 expression in CHM compared to PHM and normal trophoblasts indicates increased apoptosis and uncontrolled trophoblastic proliferation. Construction of TMA in duplicates using cores of 3 mm diameter can overcome tissue heterogeneity of complex lesions.

Detection of mitochondrial coupling factor 6 in placental tissues from preeclamptic pregnancies and its influence on biological behavior of trophoblast cells

Increased levels of mitochondrial coupling factor 6 (CF6) are present in the peripheral blood of patients with preeclamptic pregnancies, and are particularly evident in cases of early-onset or severe preeclampsia. The present study examined the location and expression levels of CF6 in the placental tissue and its effect on the biological behavior of trophoblast cells. Placental tissue microarrays, including placental villous cytotrophoblast and extravillous cytotrophoblast microarrays, were used to detect the location and relative expression levels of CF6 in the placenta using immunohistochemistry. It was found that CF6 was expressed in both the normal and preeclamptic placenta, but its levels were higher in the preeclamptic tissues. In addition, the effects of the hypoxic environment on the biological behaviors of trophoblast cells were investigated in the JAR and JEG-3 cell lines. Following induction of hypoxia, the expression levels of CF6 were increased. Moreover, exogenous addition of human recombinant CF6 attenuated cell invasion, but exerted no effect on cell proliferation. At the molecular level, the expression levels of MMP-2 were decreased and were accompanied with a reduction in cell invasion following addition of exogenous CF6. In conclusion, the increased expression levels of CF6 and its effects in reducing the invasive abilities of trophoblast cells may be involved in the pathogenesis of severe preeclampsia.

HLA-G regulates the invasive properties of JEG-3 choriocarcinoma cells by controlling STAT3 activation

The expression of human leucocyte antigen-G (HLA-G) in trophoblasts plays a crucial role in successful embryonic implantation, and reduced HLA-G expression might contribute to adverse obstetric outcomes. In this study, we silenced HLA-G expression using RNA interference in JEG-3 cells, resulting in a notably attenuated invasion capacity of the cells in a Transwell assay; however, no alterations in cell proliferation or apoptosis were observed. The down-regulation of HLA-G dampened the activation of signal transducer and activator of transcription 3 (STAT3), whereas the up-regulation of HLA-G promoted STAT3 activation and invasion in JEG-3 cells treated with human galectin-1. Most importantly, interleukin-6 (IL-6), but not galectin-1, was shown to rescue invasion deficiency in a dose-dependent manner. Thus, we demonstrate that HLA-G is able to regulate JEG-3 cell invasion by influencing STAT3 activation, which may underlie the implantation defects accompanying HLA-G hypo-expression in pre-eclampsia.