Induced Pluripotent Stem Cells

Question 1

How many genes were discovered in the 1990s and thought to be crucial for stemness?

Answer 1

24

Question 2

How were these genes crucial for stemness discovered?

Answer 2

By comparing the genes expressed in ES cells to the genes expressed when these cells were induced to differentiate.

Question 3

Forceful expression of these genes (stemness) in embryonic fibroblasts (differentiated cells) lead to the discovery of…?

Answer 3

4 growth factors
Oct 3-4
Sox-2
C-Myc
Klf-4
Once induced in embryonic fibroblasts, they were sufficient to convert the cell into a PLURIPOTENT cell

Question 4

How do you make an induced pluripotent stem cell?

Answer 4

Take an embryonic fibroblast
Forcefully express the 24 genes crucial for stemness
Cell converts into a pluripotent cell

Question 5

What happens when a pluripotent stem cell in injected into a mouse?

Answer 5

TERATOMAS!

As there is not yet complete control of these cells

Question 6

What is the potentially therapeutic use of induced pluripotent stem cells

Answer 6

A fibroblast can be taken from the patient, de-differentiate it through forceful expression and re-differentiate it along the desired cell lineage needed - thus making cells for therapy whilst avoiding the issue of immunological barriers

Question 7

What are the issues with induced pluripotent stem cells for therapy?

Answer 7

• Extremely expensive

- Induce teratomas

Question 8

Why may protein therapy be preferable?

Answer 8

This would aim to induce the existing adult stem cells to divide and differentiate using signals. Would be cheaper, less ethical concerns