Researchers have figured out how to "coax" human embryonic stem cells to organize themselves using a geometric approach.
About seven days after conception the clump of cells that will soon be a human start to specialize and take on characters that reflect their future. In the past researchers have studied this process in animals and tried to coax human embryonic stem cells by exposing them to chemical signals, but have never successfully replicated it in the lab, Rockefeller University reported.
Researchers at the University's Laboratory of Stem Cell Biology and Molecular Embryology successfully replicated the process using a geometric, as opposed to chemical, approach.
"Understanding what happens in this moment, when individual members of this mass of embryonic stem cells begin to specialize for the very first time and organize themselves into layers, will be a key to harnessing the promise of regenerative medicine," said Ali Brivanlou, Robert and Harriet Heilbrunn Professor and head of the Laboratory of Stem Cell Biology and Molecular Embryology at The Rockefeller University. "It brings us closer to the possibility of replacement organs grown in petri dishes and wounds that can be swiftly healed."
In the uterus these embryonic stem cells receive chemical cues from the tissue surrounding them, prompting them to form layers in a process called gastrulation. Cells In the center start to form ectoderm ("the brain and skin of the embryo") while others migrate outward to become mesoderm and endoderm, which turn into muscle and blood.
The research team confined human embryonic stem cells to circular glass plates treated to form "micropatterns" that that prevent these colonies from expanding at a certain capacity. When the chemical was introduced to trigger gastrulation the colonies started to form endoderm, mesoderm and ectoderm as they would under natural conditions.
"At the fundamental level, what we have developed is a new model to explore how human embryonic stem cells first differentiate into separate populations with a very reproducible spatial order just as in an embryo," postdoc Aryeh Warmflash said. "We can now follow individual cells in real time in order to find out what makes them specialize, and we can begin to ask questions about the underlying genetics of this process."
The findings could also help researchers get closer to creating "pure" populations of cells for use in medical procedures.
"These cells have a powerful intrinsic tendency to form patterns as they develop," Warmflash said. "Varying the geometry of the colonies may turn out to be an important tool that can be used to guide stem cells to form specific cell types or tissues."
The research was published the June 29th edition of Nature Methods.
