Studying apoptosis in DT40 cells - Events

Studying apoptosis in DT40 cells - Events Studying apoptosis in DT40 cells - Events

14.07.2013 Views

Studying apoptosis in DT40 cells Sandrine Ruchaud Acridine Orange! Role of apoptosis in sculpting the mouse paw E12.5! E13.5! E14.5! gift of William Wood & Paul Martin! University College, London!

<strong>Study<strong>in</strong>g</strong> <strong>apoptosis</strong> <strong>in</strong> <strong>DT40</strong> <strong>cells</strong><br />

Sandr<strong>in</strong>e Ruchaud<br />

Acrid<strong>in</strong>e Orange!<br />

Role of <strong>apoptosis</strong> <strong>in</strong> sculpt<strong>in</strong>g the mouse paw<br />

E12.5! E13.5!<br />

E14.5!<br />

gift of William Wood & Paul Mart<strong>in</strong>!<br />

University College, London!


Normal nucleus Apoptotic nucleus<br />

Which prote<strong>in</strong>s are <strong>in</strong>volved<br />

<strong>in</strong> apoptotic execution?


Key players responsible for nuclear apoptotic execution<br />

Initiator<br />

Caspases<br />

(-8, -10, etc.)<br />

Effector<br />

execution phase<br />

Caspases<br />

(-3, -7<br />

-6)<br />

Active CAD<br />

CAD/ICAD<br />

PARP<br />

P ARP<br />

Caspase-6<br />

I<br />

CAD<br />

CAD<br />

Lam<strong>in</strong>s<br />

(Lam<strong>in</strong> A/C)


Caspase-6 gene target<strong>in</strong>g<br />

5ʼ!<br />

GgPro-caspase 6!<br />

Prodoma<strong>in</strong>!<br />

N!<br />

KpnI! XbaI!<br />

XbaI! ApaI!<br />

E1! E2! E3! E4! E5! E6! E7! E8!<br />

Knockout construct!<br />

Wild type allele!<br />

Targeted allele (puro)!<br />

Targeted allele (hisD)!<br />

Large subunit! Small subunit!<br />

Start! BamHI!<br />

Stop!<br />

resistance!<br />

3 kb! cassette!<br />

2.1 kb!<br />

BamHI!<br />

BamHI!<br />

7.7 kb!<br />

puromyc<strong>in</strong>!<br />

hisD!<br />

5.3 kb!<br />

BamHI!<br />

2.7 kb!<br />

ApaI!<br />

ApaI!<br />

ApaI!<br />

C!<br />

BamHI!<br />

BamHI!<br />

BamHI!<br />

BamHI!<br />

3ʼ!<br />

Probe!


Southern blot<br />

wt<br />

Casp6 (+/-) puro<br />

Casp6 (-/-) puro/hisD<br />

7.7 kb wt allele<br />

5.3 kb puro allele<br />

2.7 kb hisD allele<br />

Northern and western blot<br />

wt (+/-) (-/-)<br />

wt (+/-)<br />

(-/-)<br />

Casp-6 mRNA<br />

Casp-3 mRNA<br />

Casp-7 mRNA<br />

β-act<strong>in</strong> mRNA<br />

Pro Casp-6<br />

α-tubul<strong>in</strong><br />

⇒ what is the specific role of caspase-6 dur<strong>in</strong>g apoptotic execution?


Apoptosis <strong>in</strong> caspase 6 -/- <strong>cells</strong> proceeds normally<br />

Et (h)<br />

wt<br />

wt<br />

(-/-)<br />

(-/-)<br />

0 2 3 4 5 0 2 3 4 5<br />

M<br />

(kb)<br />

4.0<br />

3.0<br />

2.0<br />

1.6<br />

1.0<br />

0.5<br />

No lam<strong>in</strong> A/C expression <strong>in</strong> <strong>DT40</strong> <strong>cells</strong><br />

- Lam<strong>in</strong> A is the only known substrate cleaved only by<br />

caspase 6.<br />

- Lymphoid tissues have been shown not to express<br />

lam<strong>in</strong> A<br />

Lam<strong>in</strong> A<br />

Lam<strong>in</strong> C<br />

Chicken<br />

muscle<br />

<strong>DT40</strong><br />

HeLa<br />

Jurkat<br />

anti chicken lam<strong>in</strong> A<br />

Used an apoptotic cell free system<br />

on isolated Hela nuclei


Sequential events happen<strong>in</strong>g dur<strong>in</strong>g <strong>in</strong> vitro <strong>in</strong>duced <strong>apoptosis</strong> of<br />

isolated Hela nuclei<br />

DAPI sta<strong>in</strong>ed<br />

HeLa nuclei<br />

1 2 3 4 5<br />

6 7 8 9 10


Caspase-6 deficient apoptotic extracts block apoptotic chromat<strong>in</strong> condensation<br />

%! 100!<br />

75!<br />

50!<br />

25!<br />

0!<br />

Genotype!<br />

VEID!<br />

DAPI!<br />

Lam<strong>in</strong> A!<br />

Lam<strong>in</strong> C!<br />

α tubul<strong>in</strong>!<br />

Control extracts! Apoptotic extracts!<br />

wt! (-/-)! wt! (+/-)! (-/-)! (-/-)! wt!<br />

-! -! -! -! -! +! +!<br />

Control!<br />

Apoptotic!<br />

stages!<br />

MW!<br />

(kDa)!<br />

62! 62.5!<br />

47.5!<br />

Caspase-6 is required for completion of chromat<strong>in</strong> condensation and<br />

formation of apoptotic bodies <strong>in</strong> nuclei conta<strong>in</strong><strong>in</strong>g lam<strong>in</strong> A<br />

I!<br />

II!<br />

III!<br />

IV!


Is Lam<strong>in</strong>-A cleavage critical for nuclear apoptotic execution ?<br />

Lam<strong>in</strong> A expression<br />

No lam<strong>in</strong> A expression<br />

HeLa<br />

nuclei<br />

Jurkat<br />

nuclei<br />

Jurkat<br />

GFP-lam<strong>in</strong> A<br />

nuclei<br />

Lam<strong>in</strong> A is the critical substrate that,<br />

when present, must be cleaved by<br />

caspase-6 <strong>in</strong> order for nuclear <strong>apoptosis</strong><br />

to go to completion<br />

Control extracts Apoptotic extracts<br />

wt (-/-) wt (-/-)<br />

*<br />

DAPI<br />

GFP<br />

Merged


Caspase-7 gene target<strong>in</strong>g<br />

GgPro-caspase-7!<br />

Prodoma<strong>in</strong>!<br />

N!<br />

Large subunit! Small subunit!<br />

5ʼ!<br />

EcoRI! Ev! Ew!Ex! Ey! Ez!<br />

Start! Stop!<br />

Knockout construct!<br />

5ʼ arm!<br />

3 kb!<br />

resistance!<br />

cassette!<br />

3ʼ arm!<br />

2 kb!<br />

Wild type allele!<br />

Targeted allele !<br />

(HisD or BsR)!<br />

EcoRI!<br />

11 kb!<br />

4.3 kb!<br />

C!<br />

EcoRI! EcoRI!<br />

EcoRI!<br />

3ʼ!<br />

probe!<br />

EcoRI!<br />

⇒ what is the role of caspase-7 <strong>in</strong> <strong>apoptosis</strong>?<br />

11 kb!<br />

4.3 kb!<br />

Korfali N.


Caspase-7 –/– <strong>cells</strong> show an <strong>in</strong>creased resistance to <strong>apoptosis</strong><br />

Cell viability (% of control)!<br />

100!<br />

80!<br />

60!<br />

40!<br />

20!<br />

0!<br />

.1!<br />

WT!<br />

casp 7 +/- a!<br />

casp 7 +/- b !<br />

casp 7 --/- a!<br />

casp 7 -/- b !<br />

1!<br />

10! 100!<br />

Etoposide concentration (µM)!<br />

Cell viability (% of control)!<br />

100!<br />

80!<br />

60!<br />

40!<br />

20!<br />

0!<br />

.1!<br />

1!<br />

WT!<br />

casp 7 --/- !<br />

casp 7 -/- :casp-7:EGFP !<br />

10!<br />

Etoposide concentration (µM)!<br />

100!<br />

Korfali N.


Caspase-7 deficient <strong>cells</strong> show a delay <strong>in</strong> DNA fragmentation<br />

A!<br />

bp<br />

12.0!<br />

5.0!<br />

3.0!<br />

2.0!<br />

1.6!<br />

1.0!<br />

0.5!<br />

MW!<br />

WT!<br />

0 h! 2 h! 3 h!<br />

-/-!<br />

-/-!<br />

WT!<br />

-/-!<br />

-/-!<br />

WT!<br />

-/-!<br />

-/-!<br />

B!<br />

Tunel positive <strong>cells</strong> (% of total) !<br />

100!<br />

90!<br />

80!<br />

70!<br />

60!<br />

50!<br />

40!<br />

30!<br />

20!<br />

10!<br />

0!<br />

WT!<br />

casp7 -/- !<br />

casp7 --/- :casp-7:EGFP !<br />

0 1 2 3 4 5<br />

Time (hours)!<br />

Korfali N.


Caspase-7-deficient <strong>cells</strong><br />

show delayed loss of plasma<br />

membrane asymmetry dur<strong>in</strong>g<br />

apoptotic execution<br />

An emerg<strong>in</strong>g view of the role of<br />

Caspase-7 <strong>in</strong> <strong>apoptosis</strong>. Caspase-7<br />

may function closer to the apex of<br />

the Caspase cascade.<br />

Korfali N.<br />

A!<br />

B!<br />

Annex<strong>in</strong> V positive <strong>cells</strong> (% of total) !<br />

Annex<strong>in</strong> V positive <strong>cells</strong> (% of total) !<br />

80!<br />

70!<br />

60!<br />

50!<br />

40!<br />

30!<br />

20!<br />

10!<br />

0!<br />

35!<br />

30!<br />

25!<br />

20!<br />

15!<br />

10!<br />

5!<br />

0!<br />

WT!<br />

casp 7 -/- !<br />

casp 7 -/- :casp-7:EGFP !<br />

etoposide!<br />

0! 1! 2! 3! 4! 5! 6!<br />

Time (hours)!<br />

WT!<br />

casp 7 -/- !<br />

casp 7 -/- :casp-7:EGFP !<br />

staurospor<strong>in</strong>e!<br />

0! 1! 2! 3! 4! 5! 6! 7! 8! 9!<br />

Time (hours)!


CAD knockout strategy<br />

Samejima K


Inter-nucleosomal DNA cleavage is absent <strong>in</strong> CAD -/- <strong>cells</strong> and<br />

chromat<strong>in</strong> condensation is blocked at an early stage<br />

Samejima K


ICAD and CAD/ICAD double knockout strategy<br />

Ageichik A.


Inter-nucleosomal DNA cleavage is absent and chromat<strong>in</strong> condensation is<br />

blocked at early stages <strong>in</strong> both ICAD and CAD/ICAD double knockouts<br />

Ageichik A.


Nadia Korfali<br />

Alexander Ageichik<br />

Kumiko Samejima<br />

Bill Earnshaw


Caspase Activation Is Delayed <strong>in</strong> Caspase-7–/– Cells<br />

A! 3 h!<br />

B!<br />

LEHD-AFC cleavage!<br />

(pmol/m<strong>in</strong>/mg prtote<strong>in</strong>)<br />

0<br />

DEVD-AFC cleavage!<br />

(pmol/m<strong>in</strong>/mg<br />

prtote<strong>in</strong>)!<br />

VEID-AFC cleavage!<br />

(pmol/m<strong>in</strong>/mg<br />

prtote<strong>in</strong>)!<br />

0 h!<br />

2000<br />

1500<br />

1000<br />

500<br />

2000<br />

1500<br />

1000<br />

500<br />

0<br />

2000<br />

1500<br />

1000<br />

500<br />

Time (h) 0<br />

WT! casp-7<br />

-/- !<br />

6 h!<br />

0 h!<br />

3 h!<br />

6 h!<br />

0 3 6 0 3 6<br />

WT Caspase-7-/-<br />

zEK(bio)D-aomk !<br />

label<strong>in</strong>g!<br />

Biotenylated<br />

prote<strong>in</strong>s load<strong>in</strong>g<br />

control!<br />

C!<br />

D!<br />

LEHD-AFC cleavage!<br />

(pmol/m<strong>in</strong>/mg prtote<strong>in</strong>!<br />

DEVD-AFC cleavage)!<br />

(pmol/m<strong>in</strong>/mg prtote<strong>in</strong>!<br />

VEID-AFC cleavage!<br />

(pmol/m<strong>in</strong>/mg prtote<strong>in</strong>!<br />

0 h!<br />

0.5 h!<br />

1 h!<br />

2000<br />

1500<br />

1000<br />

500<br />

0<br />

2000<br />

1500<br />

1000<br />

500<br />

0<br />

2000<br />

1500<br />

1000<br />

500<br />

0<br />

Time (h)<br />

WT! casp-7<br />

-/- !<br />

0 h!<br />

0.5 h!<br />

1 h!<br />

0 0.51 0 0.5 1<br />

WT Caspase-7-/-<br />

zEK(bio)D-aomk !<br />

label<strong>in</strong>g!<br />

Biotenylated<br />

prote<strong>in</strong>s load<strong>in</strong>g<br />

control!

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