Lecture 14: Stem Cells and Applications

Question 1

Stem Cell Characteristics

Answer 1

• not terminally differentiated, divide without limit, slow division
• give rise to 1 cell w/stem cell characteristics and 1 w/ability to differentiate

Question 2

Totipotency, Pluripotency, Multipotency

Answer 2

Toti: give rise to all cells of organism (embryonic and extraembryonic); up to 16 cells; in zygote

Pluri: give rise to all cells of embryo and adult tissue (embryonic stem cell); in blastocyst

Multi: give rise to different cells of given lineage (adult stem cells)

Question 3

Founder Stem Cells

Answer 3

• fixed number in each tissue programmed with fixed number of divisions
• short-range signal controlled
• define size of large final structures

Question 4

Transit Amplifying Cells

Answer 4

• cells that divide frequently
• transit from cell with stem cell characteristics to differentiated cell (leave basal layer for layers above)
• limited # of divisions: FINITE

Question 5

Divisional vs Environmental Asymmetry

Answer 5

Divisional - one cell w/stem cell characteristics and one with differentiating ability

Environmental - two identical cells w/one being altered by environment

Question 6

Embryonic Stem Cells and Tertomas

Answer 6

• from blastocyst, proliferate indefinitely, unrestricted development potential
• tertomas: ESC do not get proper signals, so they become a big tumor

Question 7

What transcription factors are essential for establishment and maintenance of pluripotent stem cells in embryo?

Answer 7

Nanog, Oct4, Sox2, FoxD3

Question 8

Induced Pluripotent Stem Cells

Answer 8

• transcriptions factors introduced to adult stem cells (Oct4, Nanog, Sox2, Lin28) to induce properties of ES cells
• generate patient specific iPS cells (potential to correct many incurable conditions)
• VERY high potential for teratoma formation

Question 9

Somatic Cell Nuclear Transfer

Answer 9

• somatic nucleus added to donor egg cell (custom made for patient)
• stimulate cell division and harvest inner cell mass from blastocyst (pluripotent)
• cultured pluripotent embryonic stem cells
• can be used for cloning

Question 10

SCNT in Disease Treatment challenges

Answer 10

• inefficient (may need 100s of oocytes)
• technically demanding, need to be available in many or all hospitals

Treatment of Type 1 Diabetes (generate new pancreatic stem cells for patients w/o)

Question 11

What are the 4 key regulatory proteins of ES cell character?

Answer 11

Oct3/4, Sox2, Myc, KIf4

• injection into fibroblast makes them become ES like cells

Question 12

Adult Stem Cell therapies

Answer 12

• neuro-regeneration (regenerate neuronal cells)

- differentiate in vitro/in vivo –> chondroycytes, myoblasts, osteoblasts, pancreatic B cells

Question 13

ES Cell therapies

Answer 13

• reliable, high reproducible results; establishes pluripotency
• good growth properties, solve rejection problems