Week 7 Holy- Stem Cells

Question 1

What are the two major kinds of naturally occurring stem cells?

Answer 1

• Embryonic
  
  • cells isolated from inner cell mass or epiblast of blastocysts
  • pluripotent
  • controversial
• Adult
  
  • mesenchymal stem cells (multipotent)
    
    • bone, cartilage, muscle, and fat

Question 2

Where do pluripotent or multipoptent Embryonal Carcinoma Cells come from?

Answer 2

Teratocarcinoma

(germ cell tumor)

Question 3

What are malignant stem cells?

Answer 3

Pluripotent or Multipotent stem cells from embryonal carcinomas (ECs) or teratomas.

Question 4

How do embryonal carcinomas (ECs) and teratomas form?

Answer 4

germ cell epigenetic reprogramming gone wrong

can be benign or malignant

Question 5

What are the two examples of experimentally inducing differentiated cells to become pluripotent stem cells as discussed in class?

Answer 5

• iPS
  
  • induced pluripotent stem cell
  • transcription factors + pluripotentcy inducers + differentiated cell = re-differentiation
• SCNT
  
  • Somatic Cell Nuclear Transfer
  • nucleus from differentiated cell → enucleated oocyte = reprogramming to pluripotent state
  • used for reproductive or therapeutic cloning

Question 6

What is the most recent alternative regenerative medical approach that does not require stem cells at all?

Answer 6

Direct reprogramming/conversion

• essentially transdifferentiation of one differentiated cell type into another
• no reverting back to potent stem cell state
  
  • fibroblast → neurons
  • fibroblast → cardiac muscle cells

Question 7

What are some of the risk factors of stem cell therapy?

Answer 7

• rejection of cells
• lack of efficacy
• toxicity
• tumor formation
• unwanted immune responses
• transmission of adventitious agents

Question 8

What form of stem cell therapy has been prevalent in clinics for some time?

Answer 8

Bone marrow transplants.

(promote blood cell production)

Question 9

What adult stem cell is the most mitotically active?

Answer 9

Progenitor cell

Question 10

What mechanism ensures the maintenance of stem cell genomic health?

Answer 10

“immortal strand hypothesis”

specifically segregate template strands into one daughter cell that self re-news

Question 11

What type of stem cell type poses the least adverse effects in stem cell therapy?

Answer 11

Mesenchymal stem cells.