Self-Renewing Trophoblast Organoids Recapitulate the Developmental Program of the Early Human Placenta

Area of Science:

• Reproductive Biology
• Developmental Biology
• Cell Biology

Background:

• Defective placentation causes pregnancy complications, including intrauterine growth restriction and preeclampsia.
• Human placental development studies are limited by the absence of self-renewing 3D in vitro models for trophoblast progenitor formation and differentiation.
• Existing models do not fully recapitulate the complex 3D structure and differentiation pathways of placental trophoblasts.

Purpose of the Study:

• To establish a self-renewing 3D organoid culture system from first-trimester human cytotrophoblasts (CTBs).
• To model the formation of trophoblast progenitor subtypes, including syncytiotrophoblast (STB) and invasive extravillous trophoblast (EVT).
• To provide a novel in vitro platform for studying human placental development and disease.

Main Methods:

• Purification of first-trimester human cytotrophoblasts (CTBs).
• Establishment and long-term culture of CTB organoids (CTB-ORGs) under defined conditions.
• Molecular analyses, including gene expression profiling, to assess stemness, proliferation, and differentiation markers.
• Induction of differentiation by manipulating self-renewal factors.

Main Results:

• CTB-ORGs demonstrated sustained self-renewal and proliferation, expressing key trophoblast stemness markers.
• Global gene expression profiles of CTB-ORGs closely resembled those of primary CTBs.
• CTB-ORGs spontaneously differentiated into STB and, upon withdrawal of self-renewal factors, generated EVT progenitors (NOTCH1+) and differentiated EVTs (HLA-G+).

Conclusions:

• Human CTB-organoids provide a robust and reproducible in vitro model for studying early placental development.
• This model recapitulates key aspects of trophoblast progenitor self-renewal and differentiation into STB and EVT lineages.
• The established CTB-organoid system offers a valuable platform for future research into placental diseases and developmental abnormalities.