NOTCH3 signalling controls human trophoblast stem cell expansion and differentiation

Area of Science:

• Developmental Biology
• Reproductive Biology
• Cell Biology

Background:

• Placental growth and differentiation failures are linked to severe pregnancy complications like pre-eclampsia.
• The molecular mechanisms governing trophoblast development are not fully understood.

Purpose of the Study:

• To investigate the role of NOTCH3 signaling in human placental development.
• To elucidate the regulatory mechanisms controlling trophoblast stem cell (TSC) proliferation and differentiation.

Main Methods:

• Utilized human trophoblast stem cells (TSCs), trophoblast organoids (TB-ORGs), and primary cytotrophoblasts (CTBs).
• Employed doxycycline-inducible expression of dominant-negative MAML1.
• Analyzed NOTCH3 receptor and NOTCH3 intracellular domain (NOTCH3-ICD) interactions with MAML1.
• Assessed effects of NOTCH3 signaling inhibition and overexpression on cell behavior and gene expression.

Main Results:

• NOTCH3 receptor is expressed in proliferative cytotrophoblast progenitors (CTBs).
• Active NOTCH3 signaling, via NOTCH3-ICD and MAML1 interaction, promotes trophoblast progenitor self-renewal.
• Inhibition of NOTCH3 signaling reduced TB-ORG growth, while NOTCH3-ICD overexpression promoted CTB and TSC proliferation.
• Disruption of MAML1 function led to syncytiotrophoblast differentiation but suppressed progenitor expansion.

Conclusions:

• Canonical NOTCH3 signaling is essential for human placental expansion by promoting cytotrophoblast progenitor self-renewal.
• NOTCH3 signaling acts as a key regulator in maintaining trophoblast stemness and proliferation.
• Understanding NOTCH3's role offers insights into preventing pregnancy disorders linked to placental insufficiency.