neurodegenerative diseases
What is a stem cell? Characterization of the iPS cell line
Stem cells are cells that can divide, but not They have the same characteristics as
every dividing cell in the body is a stem cell. embryonic stem cells. They have to be able to
Pluripotent stem cells can develop into all cell differentiate into all the germ layers, mesoderm,
types of our body, which is interesting for ectoderm, and endoderm. Another thing they
regenerative medicine. test is if the expression profile of the pluripotent
genes is the same, and they also do this to check
if the integrity of the DNA is still normal. During
reprogramming, viruses are added and could
cause stress/damage.
Totipotent stem cells are the cells that develop Discoveries
embryos and give rise to a whole fetus. J. Gurdon showed that the DNA of a mature cell
Pluripotent stem cells are cells that can still has all the information needed to develop all
differentiate into all the cell types in the body, cells in the frog by “cloning”.
which is useful for regenerative medicine.
Yamanaka discovered how intact mature cells in
Induced pluripotent stem cell technology mice could be reprogrammed to become
Induced pluripotent stem cells are pluripotent immature stem cells.
stem cells that have been manipulated to
function as embryotic cells again. This is also These discoveries have changed our view of
called nuclear reprogramming. The development and cellular specialization. We now
pluripotent stem cells are harvested from understand that the mature cell does not have to
blastocysts from embryonic cells and can be be confined forever to its specialized state.
grown in culture. One of these techniques to do
is called iPSC. Applications of iPSC technology
• Disease modelling
This technique was first discovered by • Drug development
Yamanaka lab, Kyoto in 2006. He proved that • Cell replacement therapy
he could reprogram pluripotent stem cells into
embryonic stem cell-like cells by using In vitro disease modelling
specialized factors. Viruses are used to iPSCs from a patient can be used to study the
introduce these factors to mice stem cells. genetics and development of a certain disease in
cell culture. Sometimes it is a change in one gene
that leads to a certain disease.
1) Postmortem tissue, a disadvantage is that you
study the end-stage of the disease
2) Animal models disadvantages: not human-
specific, drug testing is slow and no prediction of
efficacy.