Publication highlights

Several models of cell fate lineages have been presented, some proposing a traditional straight path and others a more dynamic model, where cell fate remains more flexible. Researchers at the Crick combined a range of experimental techniques - single cell transcriptomics, quantitative live cell imaging and mathematical modelling - to track cell fate and determine which path is the right one. They found that there was no singular path, and these theories were not competing explanations but complementary snapshots of human development. The team also observed the influence of two important signalling molecules, Activin and BMP4, in determining which route cells would take between mesoderm or endoderm layers.

Researchers at the Francis Crick Institute have developed a new stem cell model of the mature human amniotic sac, which replicates development of the tissues supporting the embryo from two to four weeks after fertilisation. The new 3D model – called a post-gastrulation amnioid (PGA) – closely resembles the human amnion and other supportive tissues after gastrulation. The team developed PGAs by culturing human embryonic stem cells in a series of steps with just two chemical signals over 48 hours, after which the cells organised themselves into the inner and outer layers of the amnion. A sac-like structure formed by day 10 in over 90% of the PGAs, which expanded in size over 90 days. The researchers showed that a transcription factor called GATA3 is necessary to kick-start amnion development and that signals from the amnion can communicate with embryonic cells to stimulate growth. Finally, they believe PGAs could also provide an alternative source of amniotic membranes for medical procedures like cornea reconstruction.