Stem Cells

Question 1

Pluripotent
Totipotent
Multipotent

Answer 1

Pluripotent: Have the potential to generate all cell types from germ layers

Totipotent: Have the potential to generate all cell types including extraembryonic

Multipotent: the potential to generate cells from a specific lineage

Question 2

What does it mean to say that Adult Stem Cells have limited potential?

Answer 2

They can only renew tissue from which they were derived.

However, it is looking like they might be able to trans-differentiate (renew other tissue types)

Question 3

Explain adult stem cell niche

Answer 3

microenvironment in which stem cells are found, which interacts with stem cells to regulate stem cell fate.

Question 4

What is lineage tracing?

Answer 4

(Only within last 8-10 yrs)
Lineage tracing = find and follow stem cells.

Know that stem cells turn over slowly. In old days, could label DNA with tracer. Stem cell will retain label, progeny will lose the label. Look for label retention.

It was thought that stem cell in intestinal epithelia was the +4 cell.

Question 5

What is the true intestinal stem cell

Answer 5

CBC (crypt based columnar) cells

Question 6

what are iPS cells?

Answer 6

induced pluripotent cells

Found by Yamanaka (nobel prize)

Way to reprogram cells back to a pluripotent state

Question 7

What are the 4 reprogramming factors for iPS?

Answer 7

1. Oct 3/4
2. Sox2
3. c-Myc
4. KIf4

Question 8

How do iPS cells overcome complications of allogenic BM transplants?

Answer 8

No immune rejection

Source of rejuvenated adult stem cells that were previously exhausted by attempts to repair blistered tissues

Question 9

Plasticity

Answer 9

1.

Question 10

Therapeutic potential wrt genetics?

Answer 10

Can genetically “fix” stem cells to eliminate the skin disease. Grow up the stem cells and put them back in.

Question 11

Obstacles for iPS

Answer 11

1. Discovered with viral vectors… how to get away from them?
2. Safe and efficient methods for homologous recombination (ie crispr cas9 system)
3. Differentiate iPS cells that are fixed into specific cell lineage. Currently possible into an ectodermal lineage

Question 12

How big of a patch of skin do you need to repair burns with skin stem cells?

Answer 12

the size of a postage stamp

Question 13

Where do corneal stem cells reside?

Answer 13

In the limbus (between cornea and conjuctiva)

Question 14

Role of stem cells in initiation/maintenance of cancer

Answer 14

stem cells are likely targets of carcinogens = only cells to permanently reside in epithelial tissue.

cancer stem cells can repopulate tumor and cause patients to relapse.