MIT Human Stem Cell Lab Director Maya Mitalipova on signaling pathways, mouse blastocysts, and totipotency
What is the difference between mouse stem cells and human stem cells? What are the challenges of maintaining human stem cells? PhD in Genetics and Embryology Maya Mitalipova elaborates on the current problems in the field of stem cell research.
Embryonic cells have been known for nearly 30 years, first embryonic stem cells were derived in mouse, and it was done in 1981 by two groups of researchers Evans and Kaufman and Gail R. Martin. They derived it from mouse embryos. Usually, in mammalian system, embryonic stem cells are derived from pre-implantation embryos which consist the name of the stage of the embryos, blastocyst.
Blastocyst is a spherical cell, the embryo that has about a hundred and twenty cells. And then there is a cell called inner cell mass, from which actually the whole embryo develops. Before implantation this inner cell mass can be extracted from mouse or any other mammalian blastocyst. You can actually derive them and maintain them in culture. The whole process is quite technically challenging, and especially it was challenging for other mammalian species. I think, it was quite revolutionized, the biology itself, because by using embryonic stem cells the biologists could answer lots of genetic questions.
Embryonic stem cells in a mouse were derived 30 years ago, and it’s been used as a mouse model of human diseases, mostly. So, embryonic stem cells since they were derived in culture can make indefinite cell numbers in vitro. They can change in in vitro culture, and changes can be genetic. They can acquire chromosomal abnormalities, point mutations. There are two types of embryonic stem cells. For example there are embryonic carcinoma cells, these are the first that were actually derived by the scientist. Peter Andrews in the UK had been characterized these cell very detailed. Embryonic carcinoma cells compared to embryonic stem cells — it comes from the embryo. But the difference between them is that embryonic carcinoma cells are actually derived from embryonic tumors.