Glioma-associated Oncogene 2 Is Essential for Trophoblastic Fusion by Forming a Transcriptional Complex with Glial Cell Missing-a

Abstract

Cell-cell fusion of human villous trophoblasts, referred to as a process of syncytialization, acts as a prerequisite for the proper development and functional maintenance of the human placenta. Given the fact that the main components of the Hedgehog signaling pathway are expressed predominantly in the syncytial layer of human placental villi, in this study, we investigated the potential roles and underlying mechanisms of Hedgehog signaling in trophoblastic fusion. Activation of Hedgehog signaling by a variety of approaches robustly induced cell fusion and the expression of syncytial markers, whereas suppression of Hedgehog signaling significantly attenuated cell fusion and the expression of syncytial markers in both human primary cytotrophoblasts and trophoblast-like BeWo cells. Moreover, among glioma-associated oncogene (GLI) family transcriptional factors in Hedgehog signaling, knockdown of GLI2 but not GLI1 and GLI3 significantly attenuated Hedgehog-induced cell fusion, whereas overexpression of the GLI2 activator alone was sufficient to induce cell fusion. Finally, GLI2 not only stabilized glial cell missing-a, a pivotal transcriptional factor for trophoblastic syncytialization, but also formed a transcriptional heterodimer with glial cell missing-a to transactivate syncytin-1, a trophoblastic fusogen, and promote trophoblastic syncytialization. Taken together, this study uncovered a so far uncharacterized role of Hedgehog/GLI2 signaling in trophoblastic fusion, implicating that Hedgehog signaling, through GLI2, could be required for human placental development and pregnancy maintenance.

Up-regulation of 11β-Hydroxysteroid Dehydrogenase Type 2 Expression by Hedgehog Ligand Contributes to the Conversion of Cortisol Into Cortisone

“…Recently, we demonstrated the expression patterns of HH ligands and activity of the HH signaling pathway in both human and murine placentas, and further confirmed the versatile roles of HH signaling in placental development and functions including steroidogenesis, epithelialmesenchymal transition and syncytialization (2,(15)(16)(17). In the present study, we have revealed that activation of HH pathway promotes the conversion of active cortical to inactive cortisone through GLI2-mediated induction of 11␤-HSD2 expression in human tropoblasts.…”

“…As previously reported, 11␤-HSD2 expression is upregulated during the process of placental trophoblasts fusion, namely syncytialization, and HH/GLI2 is involved in directing syncytialization (15,21). To exclude the possibility that HH/GLI2-induced 11␤-HSD2 expression is resulted from the trophoblasts fusion, we knocked down GLI2 in human trophoblast-like choriocarcinoma JAR cells, which express 11␤-HSD2 but show a weak ability to fuse (22,23), and checked the 11␤-HSD2 mRNA and protein levels.…”

“…Immunostaining of a single cell also showed that treatment with SM increased the 11␤-HSD2 expression significantly as compare with that of CM ( Figure 4E). Previous study identified that placental trophoblasts fusion is dependent on the transcomplex formation of GLI2 and Glial Cell Missing-a (GCMa), and loss of either GLI2 or GCMa leads to the failure of trophoblasts fusion (15). To further confirm whether HH/GLI2-induced 11␤-HSD2 expression is independent of trophoblasts fusion, we knocked down either GLI2 or GCMa in combination with overexpression of GCMa and GLI2.…”

High expression of Sonic hedgehog in allergic airway epithelia contributes to goblet cell metaplasia

“…Immunofluorescence staining was performed as described previously. 49 The antibodies used were as follows: CCR3 (ab36827, Abcam), vimentin (sc26002, Santa Cruz Biotechnology), CC10 (sc365992, Santa Cruz Biotechnology), MUC5AC (ab3649, Abcam), SPDEF (ab197375, Abcam), FOXA2 (Santa Cruz Biotechnology), Alexa555 or Alexa488-conjugated secondary antibody (Invitrogen, Grand Island, NY). Semi-quantitative histomorphometry for PAS, immunohistochemistry and immunofluorescence staining was performed blindly in 10 different fields for each lung section by using Image-Pro Plus 6.0 software (Media Cybernetics, Silver Spring, MD) as previously described.…”

Dysfunction of Shh signaling impaired trophoblast motility and autophagy is involved in poor placentation of recurrent miscarriage

“…Our previous studies have indicated that Hh signaling was required for EMT process of human trophoblast cells, the pregnant maintenance, placental development [27,28,[51][52][53]. Thus, in the present study, we firstly investigated the expression of Shh signaling core members in health human placental villi, our results showed that the Shh/Ptch/Smo/Gli2/Gli3 signaling axis preferred to be activated in CTB layer, and Shh protein was decreased in villous tissue of recurrent miscarriage patients while compared to the healthy control.…”