Researchers in Japan and the U.S. were able to create 3D blastocyst-like structures from stem cells, which could be used to improve research in the fields of embryogenesis and fertility.
Published in the journal Stem Cell Reports, researchers from RIKEN Center for Biosystems Dynamics Research and Gladstone Institute, found the structure they were able to generate from the stem cells very closely resemble actual blastocysts which are structures formed in the early development of a mammal. It has an inner cell mass which eventually forms into the embryo. The outer layer of the blastocyst is referred to as trophoblast. The researchers also discovered the blastocysts can induce proper changes in the uterus once they were implanted in pseudo-pregnant mice.
Scientists discovered structure while conducting other research
Upon being fertilized, an egg divides as it goes through different stages. The cells in the two-cell stage can become any type of cell. Following even more cell divisions the embryo converts into a blastocyst that's implanted in the womb where it grows into a fetus.
For years, scientists haven't been able to covert cells into totipotent, the two-cell phase. Cody Kime of Gladstone and Kiichiro Tomoda from RIKEN had done previous work on converting mouse cells to a pre-implanted stage and during that research discovered structures that look like early embryo blastocysts. Since it wasn't the researcher primary focus they could have easily discarded the finding and moved on. But instead, they opted to dig further into what they discovered, cumulating into the new research.
The structures can make proper changes to the uterus of the mice
"Perhaps our most important finding was that natural molecules found in the early mouse embryo can reprogram cultured cells to become surprisingly similar in function to early embryos," Kime said in the report, noting that after seven days of being converted the process produced between 5 and 30 self assembles blastocyst structures. The scientists found the cells had the gene expression that is found in two-cell embryos. The created structures included many of the genes related to blastocysts but at a lower than natural level which indicated the technique doesn't reproduce the cells exactly. But when transplanted in the womb of pseudo pregnant mice the structures made the changes to the uterus needed implantation.
"Totipotency is the highest order of cell potency: one totipotent cell can form the placenta and the body...everything," says Kime. "If our system can be improved to fully reach that state we will be able to improve basic research in the fields of embryogenesis and fertility, as well as basic and clinical research in regenerative medicine."