Lecture 10 - Stem Cells

Question 1

What sorts of stem cells exist?

Answer 1

Adult stem cells
Embryonic stem cells
Personalised embryonic stem cells

Question 2

What are the two different ways that stem cells can divide?

Answer 2

They can either divide symetrically that results in two identical daughter cells.
Or they can divide asymetrically that results in one stem cell and one differentiated cell.

Question 3

What are the different types of stem cells potency and an example of each?

Answer 3

Totipotent cells - can differentiate into anything e.g. zygote cells
Pleuripotent cells - can differentiate into all cells of the embryo proper (not placenta) e.g. morula
Multipotent - can differentiate into a select group of cells from a single tissue e.g. haematopoetic stem cells
Monopotent - can differentiate into a single cell type e.g. skin basal cells

Question 4

How does the microenvironment interact with stem cells in the embryo and in adults?

Answer 4

In the embryo various niche factors act on the stem cells and cause changes in gene expression. This induces proliferation or differentiation.
In adults the microenvironment maintains cells in a quiescent state and then causes proliferation if there is an injury.

Question 5

What are the intrinsic and extrinsic regulators of the microenvironment?

Answer 5

Intrinsic factors: Growth factors and transcriptional regulators, less checkpoints allow cell cycle to occur quicker
Extrinsic factors: neighbouring growth factors from other cells

Question 6

How does the tissue repair ability change in older people?

Answer 6

It gets worse because there are less stem cells as you age.

Question 7

How is the embryonic stem cell state maintained?

Answer 7

Through pleuripotency factors such as Oct4 and Sox2.

Question 8

What are the challenges of the use of stem cells in regenerative medicine?

Answer 8

Safety issues with tumour formation

Need to overcome immune rejection or give patient specific stem cells.