Cell differentiation/Stem Cells

Question 1

stem cell characteristic

Answer 1

self renewing, undiffernentaited, can be tot, pleura, multi, olive, or unipotent, can be undimmed for special functions

cancer-divide slowly, multiple drug resistance, umbridled growth possible

Question 2

adult vs embryonic stem cells?

Answer 2

adult

• need to be de-differentiated to induce pluripotent
• in partiuular regions, generally differentiated

embryoinic-ICM and pluripotent

Question 3

how are stem cells indentifiend, isolated, and maintained

Answer 3

isolated-cultured-irradiated mouse fibroblast-grotth/support

idetifed-antibodies to markers CD3R on HSCs-flourensnce

Maintained -LIF-blocks MAPK pathway-prevents differentiation

Question 4

stem cells in regen med

Answer 4

tissue repair

organ restoration

Question 5

cancer stem cells

Answer 5

self renewal-can result in relapse of cancer if not destroyed

Question 6

stem cell properties

Answer 6

unspecialized and can self renew

can be induced to differentiate into cells with special functions (differentiated cell)

Question 7

self renewel

Answer 7

assymetric division=stead state conditions-makes differentiated and undifferenteatid cells
-undif stays in niche

Symmetric divisoin=when stem cells must expand-during dev or during injury

Question 8

regulation of stem cell self renewel

Answer 8

cell intrinsic

• Tfs negatively rg expression of diffenrtiiton promoting genes
• dna binding protein (Ronin) supresses trx of differnation-inducing genes

cell extrinsic
-BMp and other stuff block MAPK pathway

Question 9

stem cell niche

Answer 9

Chemical and mechanical environemnt
-microenvironemnt

Tissue injury results in respecification of niche-cancer can cause over differentiation

Question 10

intesttinal crypty

Answer 10

1:1 ratio between stem and panted cells-need panted cells to divide

Question 11

Adult stem cells

Answer 11

Can self renew and differentiate if not differentiated

IPS stem cells-pluripotent stem cells artificially derived from a non-pluripotent

maintain and repair tissue which they find-not pluripotent

Question 12

Embryonic

Answer 12

Undifferniated from 5 day preimplantation embryo that is pluripotent

Question 13

cancer stem cells (2 types)

Answer 13

drive tumorigenesis and rise to differtitted progeny

Question 14

2 types of division

Answer 14

stochasttic-results in two stem cells or two daughter cells

Hierachical division-normal stem cell division

Question 15

differentated defintioon

Answer 15

acquired specialized structure and function

can be cancer of cells that look just like cells that should normally be three

Question 16

undifferentiated defintion

Answer 16

cell that has not yet acquired a special structure or function

-immature cancer is primitive and does not look like cells in tissue from which it arose

Question 17

dedifferentiation

Answer 17

process by which partially or terminally differentiated cell reverts to an earlier dev stage
-holy grail of stem cell research

Question 18

potency definition and 3 types +example

Answer 18

potential to differentiate

multi-access differentiate into number of cells that are related-hemopoeisis

oligopoent-can differentate into a few spefic ecells-lymphoid

unipotent-can only produce one type of cell-but have self renewal property-muscle cells
-differ from normal cells-self renewel

Question 19

totipotent vs pluripotent

Answer 19

totipotent-stem cells that are produced from fusion of egg and sperm
-give rise to embryonic and extra embryonic tissues

pluripotent-totipotent cells that can differentiate into cells from any of three germ layers-ectoderm, endoderm, or mesoderm

Question 20

zygote, embryo potency

Answer 20

zygote-totipotent

embryo-pluripotent (inner cell mass cells)

Question 21

two type of stem cells in bone marrow

Answer 21

hematopoetic (blood)and stomal (bone, carlidge, fat, connective tissue)

Question 22

Embryonic stem cells

Answer 22

aka ICM

obtained from 4-5 day old blastocyst

can be cultured in vitro under conditions preventing them from differentiating (need to stop them from differentiating)
-can be cultured to make a particular phenotype

Question 23

How are stem cells cultured in vitro

Answer 23

Plate ICM cells on layer of fibroblast feeder cells

• these bottom cells are inactivated (irradiated) and provide source of growth and attachment factors for ES cells
• produces ground substance and fibers of ECm

plate ICM cells onto tissue culture medium containing factors (LIF) that inhibit differentiation
-LIF binds to hetermdimer which activates JAK/STAT signaling-blocks MAPK pathway that would result in differentiation

Question 24

JAK/STAT and MAPK pathway and LIF

Answer 24

Lif binds to receptor that activates JAK/STAT which inhibits MAPK pathway-stops differentiation

Question 25

How to identify stem cells

Answer 25

use cell surface markers directed against specific membrane receptors on the stem cells

• or flow cytometry for HSC using common markers
  
  • analyize 10000s of cells, ells with fluorescent fingerprint-flicked into side tube

Question 26

Common markers for HSC

Answer 26

hemapoetic stem cell

CD34 and Ckit

Question 27

FACS

Answer 27

most common way to isolate stem cells

• flow cytometry
  
  • analyize 10000s of cells, cells with fluorescent fingerprint-flicked into side tube

Question 28

Diffeernation

Answer 28

process where cell becomes more specialized

differntation dramatically changes cells shape, size, etc.

changes are largely due to highly controlled mods in gene expresssion

Question 29

How to stimulate cells to differentiate 3

Answer 29

changing chemical comp of culture

alter surface of dish (mechanical comp)

modify cells by introducing genes

Question 30

How to maintain differentiated state (4 ways)

Answer 30

gene expression must be maintained

1. TF who se gene is activated can bind to enhancer of own gene
2. synthesize proteins to act on chromatin to leave gene accessible
3. single molecule-cell can make both the molecule and its receptor
4. Cells can interact with neighboring cells-stimulate each other to keep differentiated

Question 31

Regenerative medicine

Answer 31

Use stem cells to repair or replace damaged tissues

• replace damaged tissues and organs
  
  • figure out how

Question 32

mouse with human ear

Answer 32

nude mouse (no immune system)

• stem cells from embryonic
• probably hard to put back with human immune system

Question 33

Transplant stem cell-need these things

Answer 33

proliferate extensilvey and make sufficienct quantities of cells
differentiate into desired cell types
survive after transplant
function properly
avoid huryting recipient
generate tisseust aht will not be rejected

Question 34

how to get human pluripotent stem cells (5)

Answer 34

1. from morula stage f embryo
2. from ICM of blastocyst
3. from germ cells of fetus
4. from adult (only one without moral issues)
5. somatic cell nuclear transfer (creating ovum with donor nucleus)

Question 35

IPS (indueced plurpotent stem cells) + important things about this type of stem cell

Answer 35

start of as adult, repgrom back (using nuclear transfer/cell/fusiongenetic reprogramming)

• CAN BE PATEINT MATCHED
• need 4 out of many candicacn genes to revert it back

Question 36

challgenges to reprogramming

Answer 36

low effecny

genomic insertion

tumors

incomplete reprogrammng

Question 37

alternative approaches to reprogramming

Answer 37

chemicals, alternative vectors (plasmids instead of retrovirus), microRNAs, stimulus triggered acquisition of pluripotency (did not work…)

Question 38

iPS medical research

Answer 38

test drug on stem cells, create organs, repair tissues

Question 39

Cancer cell theories new vs old

Answer 39

old-all cells are equally tumorgeneic and cancer is prliferative (too many cells reproducing)

new-cancer stem cells-properties of normal stem cells especially self-renewal and multi potency

• upreulation is due to disruption in reg system mech in stem cell renewal
• cancer is a stem cell disorder-not proliferation

Question 40

CSCs imprtant facts (4)

Answer 40

likely causes relapses and metastasis

• self renewal strong-when attack, make more of stem cell during attack of differentiated cells
  
  • asymmetric division
• divide slowly-plenty of time to repair radio/chemo damage
• multiple drug resistance transporters on cell surface
  
  • remains in low frequency tho (i think this is good)
• unbridlged cell growth mutation-population that expressed genes from drug resistance and antiapop mechs will render chemo ineffective

Question 41

chemo attacks

Answer 41

bulk of cells-should try to attack cancer stem cells