Transplantation of early human neural fate organoids to the chick embryo chorioallantoic membrane

FIORE, LUCIANO; HOLUBIEC, MARIANA; BIANCHELLI J; HALLBERG A; SPELZINI, GONZALO; SCICOLONE, GABRIEL; FALZONE, TOMÁS

Ciudad Autónoma de Buenos Aires

Congreso; SAN 2022 Meeting; 2022

Sociedad Argentina de Investigación en Neurociencias (SAN)

Human brain organoids are an emerging technique that allows us to recapitulate in vitro the early development of the human brain. Nevertheless, one of the big limitations of this model is the lack of vascularization which plays indispensable roles, not only in brain homeostasis but also in brain development. In addition to the delivery of oxygen and nutrients, accumulating evidence suggests that the vascular system of the brain regulates neural differentiation, migration, and circuit formation during development.The aim of this work is to develop vascularized human brain organoids using extraembryonic chicken endothelial cells in order to obtain a faster, better and more representative model of the human brain development in vitro.The chick embryo chorioallantoic membrane (CAM) is a rich vascularized extraembryonic membrane. Since the chick embryo is naturally immunodeficient, we transplanted early human neural fate organoids (neuroepithelium stage) into chicken embryos of 7 days of development (E7) WT chicken CAM. After 5 days of incubation (E12 chicken embryo) we opened the eggs, fixed the CAM and analyzed the engraftment organoids by immunohistochemistry and hematoxylin & eosin staining. We found that organoids got vascularized and proliferated next to the CAM vessels. We also observed cells expressing the neural marker Pax6, integrated and surrounded by allantoid derived chicken cells that expressed TBX5. These preliminary results allow us to conclude that the chicken CAM is a suitable environment to host human brain organoids and that CAM would support the engraftment of more developed brain organoids (cerebral tissues), and their growth therein could faithfully recapitulate most of the characteristics of the brain development process including: growth, angiogenesis and neural differentiation.