Notch-dependent RBPJκ inhibits proliferation of human cytotrophoblasts and their differentiation into extravillous...

Area of Science:

• Reproductive biology
• Cell signaling
• Developmental biology

Background:

• Abnormal invasive trophoblast development is linked to pregnancy diseases like pre-eclampsia.
• Signaling pathways controlling trophoblast formation and differentiation are not fully understood.

Purpose of the Study:

• To investigate the role of the canonical Notch pathway and its transcription factor RBPJκ in regulating human trophoblast proliferation and differentiation.
• To elucidate the molecular mechanisms underlying trophoblast development in early pregnancy.

Main Methods:

• Immunofluorescence staining of first-trimester placental tissue to detect RBPJκ and MAML proteins.
• In vitro differentiation of primary cytotrophoblasts on fibronectin.
• Gene silencing of RBPJκ using siRNAs in villous explant cultures and primary trophoblasts.
• Analysis of cell proliferation (outgrowth, BrdU labeling), motility, and expression of differentiation markers (cyclin D1, integrin α1, ADAM12, T-cell factor 4).

Main Results:

• RBPJκ and MAML proteins are expressed in proliferative and differentiated trophoblasts.
• RBPJκ expression and Notch target gene HES1 levels decrease during in vitro trophoblast differentiation.
• RBPJκ silencing increases trophoblast proliferation and expression of differentiation markers, without affecting cell motility.
• Notch-dependent RBPJκ activity appears crucial for maintaining balanced trophoblast proliferation and differentiation.

Conclusions:

• Notch-dependent RBPJκ activity is essential for controlling trophoblast proliferation and differentiation rates in early human pregnancy.
• This pathway may prevent excessive trophoblast overgrowth and premature differentiation into extravillous trophoblasts (EVTs).
• Findings provide insights into the pathogenesis of pregnancy diseases linked to abnormal trophoblast development.