L22 - Stem Cells

Question 1

Functions of stem cells:

Purpose:

Microenvironment:

Answer 1

To renew and to differentiate.

Find treatments to diseases.
Find how cell division is controlled.
To see how development occurs.

Microenvironment around stem cells provides support and signals regulating self renewal and differentiation.

Question 2

Types of stem cells:

Answer 2

Totipotent - fertilised egg.

Pluripotent - blastocyst. Has inner cell mass. Is an embryonic stem cells. Gives rise to the three germ layers.

Multipotent - hematopoietic, neural and mesenchymal stem cells ~ adult tissue stem cells.
Hematopoietic cells make RBC.
Neural cells make cells of the NS.
Mesenchymal cells make cartilage and bone.

Question 3

Blastocyst:

Answer 3

Has trophoblast surrounding the inner cell mass where you find the embryonic stem cells.
Made after 5 days.

Can be grown on agar plate and differentiation can be regulated to make specific types.

Are pluripotent.

Question 4

Ways to ensure cultured cells are stem cells:

Answer 4

Inspect cells under a microscope to see if undifferentiated and healthy.

Isolate inner cell mass and place on irradiated MEFs. Cells will renew each time - will dissociate and will be replated.

Can use pluripotency markers such as Oct4, NANOG, SOX2.

Question 5

Stem cells controversy:

Answer 5

Can take embryonic stem cells from blastocysts but this destroys developing blastocyst. ~ basically we’re taking life 👍

Question 6

Tissue stem cells:

Answer 6

From cord blood and fetal blood.
Makes tissues during development.
Found in adult tissues where needed for repair and replacement.

Are multipotent.

Question 7

Two neurogenic regions in the brain:

Answer 7

Subventricular zone and subgranular zone

Question 8

Induced pluripotent stem cells:

Benefits:

Answer 8

Isolate hair root shaft cells and obtain keratinocytes. Add yamanaka factors (induces pluripotency - SOX2, OCT4, KLF4, cMYC).
Cells become pluripotent.

No ethical issues. Similar properties to embryonic stem cells.
Can create stem cells from patient. No need for embryo.

Used for transplantation, and drug discovery.
Umbilical cord stem cells can treat burns and leukaemia.
Limbal stem cells to treat cornea diseases.
Mesenchymal stem cells to treat bone and cartilage damage.