Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

modeeling disease > l13stemcells > Flashcards

l13stemcells Flashcards

1
Q

what is a pluripotent cell defined as?

A

a cell which can generate any cell of the body (including germ cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is a stem cell?

A

A cell which can self renew (in response to a particular signal), and can also differentiate to give rise to a variety of cell types (according to differentiation signals)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

are embryonic stem cells pluripotent?

A

yes - early embryonic stem cells are pluripotent but begin to lose pluripotentcy/differentiate during gastrulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the defining features of pluripotent stem cells?

A
  • expression of pluripotency factors (nanog, sox2, oct4)

- teratocarcinoma formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When does teratocarcinoma formation occur?

A

when pluripotent stem cells are grafted onto a mouse kidney- tumour forms containing all cell types

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the pluripotency factors?

A

Nanog, sox2, oct4

-these 3 transcription facotrs in combination define pluripotent SCs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

at what stage is the inner cell mass pluripotent?

A

E4.0 - inner cell mass contains PCs surrounded by trophectoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

why are (human) embryos difficult to study?

A
  • small number of cells
  • develop in utero
  • ethical issues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what critical signals maintain cells in a self renewing, undifferentiated state?

A

FGF2 and TGFb (human)

BMPs (mouse)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

how are pluripotent cells captured?

A
  • plate inner cell mass cells on layer of feeder cells (support ES cell growth - iradiated stromal cells)
  • once divided a couple of times-disaggregate ESCs and replate
  • get ES cells to permantly express reporter transgene e.g. GFP(so ES cells can be seen)
  • critical signals (TGFb and FGF2) added to maintain in proliferative state
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is a chimeric mouse?

A

A mouse composed of cells with two different genotypes

  • an individual derived from 2 different genotypes
    e. g. mouse ESCs can be reintroduced into normal blastocyst and contribute to normal development - can be followed as are GFP labelled
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how can adult somatic cells be reprogrammed to a pluripotent fate?

A
  • introduce pluripotency factors (sox2,nanog,oct4 and cmyc)
  • c-myc-proliferation
  • if cultured in right environment with right factors - can resemble pluripotent cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the two approaches to get in vitro differentiation?

A

1) 3D approach

2) 2D/adherent approach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

whats happens in the 3D approach to get in vitro differentiation (and give advantages and disadvantages)?

A
  • signals removed which keep cell in undifferentiated state
  • cells grown in aggregates/embryoid bodies
  • embryoid bodies contain many cell types
  • advantage - more accurate representation of invivo differentiation (cell-cell interactions)
  • disadvantage - difficult to observe and dissect
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how is Wnt signalling labelled in embryoid bodies?

A

Axin:Lacz (when Wnt signalling, axin is active-lacz expressed)

  • show wnt initiates formaiton of organoids/mini organs
  • heart cells from EBs can beat - showing functionality
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how can it be confirmed that a cell has differentiated into the correct target cell type?

A
  • is expression of the correct markers

- has functionality (e.g. heart cell - has cardiac AP/ can beat)

17
Q

what happens in the 2D/adherent approach to get in vitro differentiation (and give advantages and disadvantages)?

A
  • plate defined number of ESCs on right substrate/ECM
  • remove signals which keep ESCs in undifferentiated state
  • grow in defined medium with appropriate amounts of a signal

advantage- can test roles of specific signals
disadvantage - loss of cell/cell contact/communication which may occur in vivo

18
Q

what is an early mesodermal marker?

A

T(bra)

19
Q

what happens in microcephaly?

A
  • small brain
  • get seizures - neurological defects
  • autosomal recessive (CDKsrap2) gene)
20
Q

what was shown when a skin fibroblast was taken from a microcephaly patient?

A
  • skin fibroblast taken and intorduced to pluripotency factors - becomes pluripotent (iPS cell)
  • was shown that patient iPS cells produced smaller cerebral organoids on a dish with less neural progenitors
21
Q

what virus is associated with mucrocephaly?

A
  • Zika virus
  • when cells exposed to zika virus cerebral organoids were smaller
  • zika virus increased cell death (marked by cas 3 and labelled zika virus)
  • death of cells blocked by emricasan - prevented small organoids / microcephaly phenotype
22
Q

what is an embryonic stem cell?

A

a pluripotent stem cell which is derived from the inner cell mass of a blastocyst at an early stage - pre-implantation

23
Q

give some neural disease modelling problems

A
  • some diseases have multiple genetic causes
  • complex phenotypes
  • late onsets
  • lack of efficient differentiation protocals
24
Q

what has cell replacement been used to try to treat?

A

parkinsons (tremors, shaking, stiffness)

  • lack of dopinergic neurons in substantia nigra
  • TH- tyrosine hydroxylase - enzyme derived in dopinergic synthesis
  • hES cells derived from MDA neurons
  • transplant hES stem cells into a mouse - model of parkinsons- evidence for improved motor function
25
Q

give the challenges of cell replacement

A
  • immune reaction/tumour formation
  • positional identity
  • progenitors vs mature differentiated cells
  • is it replacement or in vivo regeneration

modeeling disease (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions