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

Defective placentation is the underlying cause of various pregnancy complications, such as severe intrauterine growth restriction and preeclampsia. However, studies on human placental development are hampered by the lack of a self-renewing in vitro model that would recapitulate formation of trophoblast progenitors and differentiated subtypes, syncytiotrophoblast (STB) and invasive extravillous trophoblast (EVT), in a 3D orientation. Hence, we established long-term expanding organoid cultures from purified first-trimester cytotrophoblasts (CTBs). Molecular analyses revealed that the CTB organoid cultures (CTB-ORGs) express markers of trophoblast stemness and proliferation and are highly similar to primary CTBs at the level of global gene expression. Whereas CTB-ORGs spontaneously generated STBs, withdrawal of factors for self-renewal induced trophoblast outgrowth, expressing the EVT progenitor marker NOTCH1, and provoked formation of adjacent, distally located HLA-G+ EVTs. In summary, we established human CTB-ORGs that grow and differentiate under defined culture conditions, allowing future human placental disease modeling. •Derivation of cytotrophoblast organoids from human placenta•Long-term expansion of trophoblast organoids in a chemically defined medium•Formation of the extravillous trophoblast lineage under defined culture conditions Failures in human placental development have been associated with severe pregnancy complications. However, due to the lack of a self-renewing model system, mimicking 3D in vivo growth and differentiation of placental trophoblast, the underlying mechanisms remain poorly understood. Herein, long-term expanding trophoblasts organoids were established that proliferate and differentiate under defined culture conditions allowing investigating normal and pathological placentation.