3. Human Embryonic Stem Cells - Isolation, Regulation and Ethics

Question 1

What is a stem cell?

Answer 1

A single cell that can give rise to a progeny that differentiate into any of the specialized cells of embryonic or adult tissues. They are totipotent They can self renew

Question 2

Are stem cells totipotent?

Answer 2

Yes

Question 3

Are stem cells able to self renew?

Answer 3

Yes

Question 4

What is symmetrical division?

Answer 4

When stem cells divide and give rise to identical daughter cells

Question 5

What is asymmetrical division?

Answer 5

When stem cells differentiate into lineage-specific somatic (adult) cells

Question 6

What is the primary biological property of a stem cell?

Answer 6

It can self renew

Question 7

What are stem cell markers?

Answer 7

Stro-1

CD146

Alpha-smooth muscle actin

Oct 4 (Octamer- binding transcription factor 4)

Question 8

What is genomic imprinting?

Answer 8

Allows constant rounds of proliferation without differentiation

Epigenetic system that determine monoallelic expression of a subset of genes according to parent of origin

Question 9

What are the different types of stem cells?

Answer 9

Embryonic

Germinal

Nuclear Transfer Somatic Cell (NTSc)

Somatic progenitor cells / Adult Stem Cells

Induced pluripotent stem cells (iPS)

Question 10

Where do embryonic stem cells originate?

Answer 10

Pre-implantation blastocyst

Can proliferate indefinitely

Question 11

Where do germinal stem cells originate?

Answer 11

Early embryogenesis

Slightly restricted

Self renew

Removed from germ layer

Question 12

What are Nuclear transfer Somatic Cells?

Answer 12

Reprogrammed adult somatic cells

Somatic cell nucleus transferred to oocyte

Stimulated

Question 13

What are somatic progenitor cells / Adult stem cells?

Answer 13

Cells of a normal adult organ always replaced by progenitor cells or “transit - amplifying cells”

E.g. Bone marrow, MSCs etc

Question 14

What are Induced pluripotent stem cells (iPS)?

Answer 14

Reprogrammed adult somatic cells

Question 15

What are Embryoncal carcinoma cells?

Answer 15

Cells of teratocarcinomas derived from sponatneous gonadal tumours in 1970

Question 16

What are Embryonic germ cells?

Answer 16

Isolated from pluripotent cells of preimplantation embryos or primordial germ cells

Question 17

What are embryonic stem cells (hES)?

Answer 17

Derived from donated excess IVF embryos

Or

Pathogenetic activation of stem cells in inner cell mass

Question 18

What are trohpoblast stem cells?

Answer 18

Isolated from trophectoderm cell linage

Restricted potential

Question 19

From where are embryonic stem cells derived?

Answer 19

Inner cell mass of blastocyst (ICM)

They are pluripotent

Question 20

What does pluripotent mean?

Answer 20

A cell is capable of differentiating into any cell/lineage (ecto, meso and endoderm)

Question 21

What potency is the zygote?

Answer 21

Totipotent

Basically batman, can do anything

Question 22

What does stemness mean?

Answer 22

Essential characteristic of stem cells that distinguishs it from other cells

Self renewel

Multilineage potential

Question 23

What are stemness-related genes?

Answer 23

Genes acitvely involved in control of SC properties

Question 24

Why are adult stem cells sorta shit?

Answer 24

Some stemness genes are lost

Question 25

How were stemness genes first discovered?

Answer 25

Systematic transcipriptional profiling of mouse ESCs, compared to Neural SC and Haemopoetic SCs

Question 26

What controls the stem cell state?

Answer 26

Small number of "core" transcriptional factors

Question 27

What genes govern ESCs pluripotency?

Answer 27

Oct4 Sox2 Nanog

Question 28

What does Oct4 do?

Answer 28

Functions as heterodimer with Sox2

Question 29

What does Nanog do?

Answer 29

Promotes undifferentiated cell state Co-occupies sites in genome with Oct4 and Sox2

Question 30

What does reprogramming of a Somatic Cell by nueclear transfer etnail?

Answer 30

Adult Somatic Cells have their nucleus transferred to an oocyte

Question 31

How was the sheep dolly made?

Answer 31

Via SCNT Late 90s

Question 32

What is the process for SCNT cloning?

Answer 32

1. Cells from donor are grown 2. Revmoval of DNA from egg 3. Donor cell placed next to empty ovum, small current allows fusion 4. Ovum is tricked, thinking its been fertilized 5. Embryo implanted

Question 33

What other examples of cloning have there been?

Answer 33

Rhesus monkey "Tetra" Family of pigs Mira the Goat Copy cat Snuppy, south Korea

Question 34

Who discovered Induced Pluripotent Stem Cells?

Answer 34

Shinya Yamanaka (UofKJ) John. B Gurdon

Question 35

What are induced pluripotent stem cells (iPS)?

Answer 35

Reprogramming of fibroblasts into pluripotent ES-cell-like state

Question 36

What transcription factors are "forced" in iPS and what are these factors called?

Answer 36

They are called Yamanaka or SKOM factors Sox2 Klf4 Oct4 c-myc (transcriptional regulator)

Question 37

What do you want to convert a fibroblast to in regards to iPSCs?

Answer 37

An intermediate epithelial cell via MET

Question 38

How is EMT repressed in the reprogramming of iPSCs?

Answer 38

Stemness factors **Sox2/Oct4 -** supress snail **c-myc - **downregulates TGFB **Klf4** - induced expression of E-cadherin, decrease snail

Question 39

Some ethical issues associated with ES research?

Answer 39

Creation of life for destruction Concern over SCNT for cloning humans Concern over exploitation of women for eggs

Question 40

What body is stem cell research governed by in au?

Answer 40

NHMRC National Health and Medical Research Council

Question 41

What are the pros or potential useso of iPS?

Answer 41

Regenerative medicine Cloning Organi cloning

Question 42

What are some of the safety concerns associated with iPS?

Answer 42

Potential formation of teratomas on transplantation Tumorigenesis Aberrant reprogramming Immunorejection