Dr. Naomi Moris and Professor Alfonso Martinez Arias at the University of Cambridge, along with colleagues across several research institutes in Europe, developed a protocol titled “Generating Human Gastruloids from Human Embryonic Stem Cells.” They posted it on the Protocol Exchange as an independent research object associated with a manuscript submitted and ultimately published in the journal Nature: “An in vitro model of early anteroposterior organization during human development.”
In general, their research focuses on gastrulation, a process in embryonic development that governs the shape of an embryo two to three weeks after an egg is fertilized. Before this point, the embryo is a tiny mass of cells. These cells begin to arrange themselves into a characteristic shape as the embryo undergoes gastrulation, where three layers of cells develop that go on to form internal organs, muscle, bone, neural tissue, and skin.
Studying the process of human gastrulation has been a challenge, partly because it is technically difficult to observe or manipulate human embryos inside or outside the human body. As a consequence, researchers have been unable to uncover some of the biological mysteries behind gastrulation.
Moris, Martinez Arias and colleagues developed a step-by-step protocol describing a process for successfully generating human gastruloids from human embryonic stem cells (ESCs) for use in a lab setting.
“Traditional stem cell cultures rely on flat plastic dishes and are often directed to differentiate into a single lineage or cell type,” said Moris. “This is vastly different to the embryo, which is a three-dimensional structure in which cells closely interact with one another and differentiate to all the lineages of the body.”
Their protocol provides a new way for researchers to view gastrulation: literally from multiple angles.
“This protocol is unique and important in that it is the first description of three-dimensional gastruloids produced from human ESCs. As such, various features of embryo development that are human-specific could be modeled using this system,” said Moris.
Moris and Martinez Arias say the protocol is directly useful to developmental biologists. And because their model makes use of human ESCs, a key element of the embryo’s development, it is useful to a broad range of stem cell biologists, who often have difficulty accessing embryonic material.
“Our in vitro model can be used to answer a number of interesting research questions, such as how symmetry is broken in early embryos, how multiple lineages emerge and are coordinated during differentiation, and how spatial and temporal patterns are organized, amongst others,” said Moris. “The advantage of the system being derived from human ESCs means it has potential relevance towards more applied questions, such as the role of genetic mutations or environmental perturbations on early human development.”
Moris and Martinez Arias made their protocol accessible through the Protocol Exchange, part of the Nature Portfolio, to enable more research on human embryonic development and to ensure the scientific community had a protocol that is easily accessible and reproducible.
“Making this protocol freely available allows any researcher to reproduce our experiments and use the system we developed towards their own research aims,” said Martinez Arias. “This means we can be open in sharing our observations, others can easily access our latest methods, and the field as a whole can try to work towards greater reproducibility across labs trying to answer a host of questions related to early embryonic development – whether using cell biology, imaging, molecular or transcriptomic techniques, comparative analysis, clonal populations, or any other approach.”
In June 2020, their article and associated protocol were concurrently published in Nature and the Protocol Exchange. So far, the article has logged more than 21,000 accesses and 34 citations; and the protocol, which has its own DOI, independently logged one citation and nearly 1,300 page views.
Moris and Martinez Arias hope that broad use of the protocol will ultimately lead to its improvement. As subsequent versions of the protocol are developed and uploaded to the Protocol Exchange, they will be made instantly available to the scientific community.
“We are hopeful that advances can be made to the throughput or efficiency of our protocol, as well as to adapt it to other human cell lines or to promote further cell type differentiation,” said Moris. As we continue to explore the potential of the system, we will be referencing the original protocol as well as improving it to expand the potential of the model.”