Tuesday, July 04, 2023

New Model Provides Unprecedented Window Into Human Embryonic Development

Amazing stuff!

"Two to three weeks after conception, an embryo faces a critical point in its development. In the stage known as gastrulation, the transformation of embryonic cells into specialized cells begins. ... Studying this process in the human-specific context has posed significant challenges to biologists, but new research offers an unprecedented window into this point in time in human development. ...
A groundbreaking model that includes both embryonic and extraembryonic components will allow researchers to study how these two parts interact around gastrulation stages—providing a unique look at the molecular and cellular processes that occur, and offering potential new insights into why pregnancies can fail as well as the origins of congenital disorders. ...
The ethical questions are profound, including whether these models have the potential to develop into human beings. ... the principal investigator of the study, emphasizes that they do not. ...
The majority of previous embryo models of developmental stages around gastrulation were single-tissue models that only contained the embryonic component. ...
While researchers have learned a great deal from embryos of other species such as mice, the lack of accessibility to human embryos has left significant knowledge gaps about our development. ..."

From the abstract:
"Investigating human development is a significant scientific challenge due to the technical and ethical limitations of working with embryonic samples. In the face of these difficulties, stem cells have provided an alternative to experimentally model inaccessible stages of human development in vitro. Here, we show that human pluripotent stem cells can be triggered to self-organise into three-dimensional structures that recapitulate some key spatiotemporal events of early human post-implantation embryonic development. Importantly, our system reproducibly captures spontaneous differentiation and co-development of embryonic epiblast and extra-embryonic hypoblast-like lineages, establishes key signalling hubs with secreted modulators, and can undergo symmetry breaking-like events. Single-cell transcriptomics confirms differentiation into diverse cell states of the peri-gastrulating human embryo without establishing placental cell types, including signatures of post-implantation epiblast, amniotic ectoderm, primitive streak, mesoderm, early extra-embryonic endoderm, as well as initial yolk sac induction. Collectively, our system captures key features of human embryonic development spanning from Carnegie-stage16 (CS) 4 to CS7, offering a reproducible, tractable, and scalable experimental platform to understand the basic cellular and molecular mechanisms that underlie human development, including new opportunities to dissect congenital pathologies with high throughput."

New Model Provides Unprecedented Window Into Human Embryonic Development < Yale School of Medicine




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