Tissue bioengineering/ iPS cells

Question 1

List three types of stem cell

Answer 1

Embryonic
Adult
Induced pluripotent

Question 2

What is potency?

Answer 2

A measure of how many types of specialised cell a stem cell can make

Question 3

What is meant by pluripotent?

Answer 3

Can make all types of specialised cells in the body

Embryonic stem cells are pluripotent

Question 4

What is meant by multipotent?

Answer 4

Can make multiple types of specialised cells but not all types
Adult stem cells

Question 5

What is an embryonic stem cell taken from?

Answer 5

The inner cell mass
This is surrounded by the trophoectoderm
Taken from the blastocyst of around 50 to 100 cells

Question 6

Give the properties of a stem cell

Answer 6

Self renew indefinitely
Divide rarely
High potencty
Rare

Question 7

Give the properties of a progenitor

Answer 7

Transient amplifying cell
Comminted progenitors will not renew
Multipotent
Divide rapidly

Question 8

What is a stem cell niche?

Answer 8

A microenviroment around stem cells which provides support and signals regulating self renewal and differentiation

Question 9

A haematopoietic stem cell divides in to what?

Answer 9

NK cells
T cells
B cells
Platelets
Erythrocytes
Macrophages
Neutrophils
Eosinophils
Basophils

Question 10

Where are HSCs isolated from?

Answer 10

The bone marrow

Question 11

Give types of cells that could arise from a neural stem cell

Answer 11

Neuron
Interneuron
Oligodendrocytes
Type 2 astrocytes
Type 1 astrocytes

Question 12

Which type of cells may derive from a gut stem cell?

Answer 12

Paneth cells
Goblet cells
Endocrine cells
Columnar cells

Question 13

Who discovered that mature cells can be reprogrammed?

Answer 13

John B Gurdon

Shinya Yamanaka

Question 14

Describe the experiment performed by John B Gurdon which provided evidence that cells can become reprogrammed

Answer 14

1) He eliminated the nucleus of a frog egg and replaced it with the nucleus from a specialised egg in a tadpole
2) The modified egg developed in to a normal tadpole
3) Subsequent nuclear transfer experiments have generated cloned mammals

Question 15

What did Yamanaka do?

Answer 15

Identified a cocktail of 4 transcription factors that can induce pluripotency

Question 16

What are the advantages of iPS cells?

Answer 16

No need for an embryo

Can get individual specific pluripotent cells

Question 17

Give the steps in generating iPS Cells from adult fibroblast cells

Answer 17

1) Cells taken from the normal mouse engineered to allow selection of iPS cell
2) Gene delivery selection and growth in culture
3) iPS cells injected in to the blastocyst
4) Implant in to to a surrogate mother
5) Mate chimeric mouse offspring with normal mouse
6) iPS derived mouse is produced

Question 18

What are the clinical advantages of iPS cells?

Answer 18

Ability to differentiate in to many cell types
Vastly renewable
Easily accessible
Individual specific ie personalised or non immunogenic

Question 19

Give obstacles in therapeutic application of iPS cells

Answer 19

1) Use of harmful oncogenes as part of the reprogramming factors
2) Use of viral vectors for gene delivery carries a risk of mutagenesis
3) Low efficiency as well as slow kinetics of reprogramming
4) Lack of robust and reliable differentiation protocols for human iPS cells