From Single Stem Cells to an In Vitro Model of the Post-implantation Human Embryo: A Step-by-Step Guide.

Area of Science:

• Developmental Biology
• Stem Cell Biology
• 3D Embryo Modeling

Background:

• Investigating early human embryonic development is challenging due to ethical and technical limitations.
• Three-dimensional (3D) modeling using human pluripotent stem cells (hPSCs) offers a promising avenue for studying post-implantation embryos.
• Existing models may not fully capture the complexity of both embryonic and extra-embryonic lineage development.

Purpose of the Study:

• To detail the generation of a novel 3D stem cell-based embryo model, the human extra-embryoid (hEE).
• To demonstrate the model's capacity to recapitulate key spatiotemporal events of peri-gastrulation development.
• To provide a robust protocol for in vitro generation and culture of hEEs.

Main Methods:

• Utilized human pluripotent stem cells (hPSCs) to construct the 3D human extra-embryoid (hEE) model.
• Established culture techniques for maintaining hPSC morphology and promoting differentiation.
• Developed troubleshooting strategies for efficient and robust hEE generation.

Main Results:

• Successfully generated the human extra-embryoid (hEE), a 3D stem cell model of early human development.
• The hEE model efficiently captures key events of peri-gastrulation, including the formation and co-development of embryonic and extra-embryonic lineages.
• High efficiency and robustness of the model were observed across different genetic backgrounds.

Conclusions:

• The human extra-embryoid (hEE) model represents a significant advancement in studying post-implantation human embryonic development in vitro.
• This model provides a powerful tool for investigating the complex processes of lineage specification and development during early human embryogenesis.
• The detailed protocol facilitates the widespread adoption and application of hEEs in developmental biology research.