environmental heat stress induces epigenetic inheritance
TRANSCRIPT
Environmental Heat Stress Induces Epigenetic Inheritance of Robustness in Artemia Model
Parisa Norouzitallab, Kartik Baruah, Gilbert Van Stappen, Karel De
Schamphelaere, Patrick Sorgeloos & Peter Bossier
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Crustacean aquaculture
Highly demanded High market value
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Finding solution
Finding solution to the problem of the disease is a primery goal
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Parental manipulation to improve phenotypes in progenies
F0 manipulation
Selection Epigenetics
Intense pressure Across generations Long period of time
Major loss of the miss-fit Labor intensive
Mild pressure One generation
Short period of time Minor loss of miss-fit
Labor intensive
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DNA molecule can record the environment
Epigenetic is the study of heritable changes in gene expression and function that cannot be explained by
changes in DNA sequence
HERITABLE REVERSIBLE
Stressed
mom
Anxious
daughter
Anxious
granddaughter
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Constraints for using shrimp as model organism
Long culture period of approximately 1 year for one generation
Labour intensive
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Selection of the model organism
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Short generation time – 3 generations in about 6 months
Genome is sequenced
Easy and cheap to maintain and manipulate
Produce large numbers of offspring
Artemia as model organism for our studies
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Parthenogenesis
NO MALE
Clonal population
Bisexual
Wild population maternal/paternal
heredity
Artemia as model organism for epigenetic studies
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F1 F2 F3 or more
Cyst (dormant egg) production – Common garden experiments
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F1 F2 F3 or more
Common garden experiments – axenic /gnotobiotic
Chemical removal of the embryo outer shells Sodium hydroxide hypochlorite solution
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Abiotic stressor and transgenerational inheritance of robustness
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No
n-l
eth
al
he
at s
ho
ck
Induction of heat shock protein 70 (HSP70)
Baruah et al. (2012). Aquaculture. 334-337:152-58
Protection against subsequent stressors abiotic - lethal heat shock biotic - pathogenic Vibrio campbellii
Background information
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Heat shock protein (HSP) 70 against abiotic stressors
Induced after exposure
to stressors
Synthesized constitutively in the cells
(heat shock cognate 70)
Role in house keeping Danger signal
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(clonal population)
Parthenogenetic Artemia
TF1 CF1
TF2 CF2
TF3 CF3
I S O
T H E R M I C
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Common garden test - verifying stress resistance phenotypes
42°C for 15 min
Or
Vibrio campbellii 107 cells/ml
Or
Zinc
20 instar II nauplii in 6 replicates
F1 F2 F3
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Thermo-tolerance test
*** ***
*** *** *** *** *** ***
0
0,2
0,4
0,6
0,8
1
0 3 6 9 12 15 18 21 24 27
Pro
po
rtio
n o
f th
e s
urv
ive
d a
nim
als
Time (h)
TF1
CF1
*** ***
*** ***
*** *** *** ***
** **
0
0,2
0,4
0,6
0,8
1
0 3 6 9 12 15 18 21 24 27
Pro
po
rtio
n o
f th
e s
urv
ive
d a
nim
als
Time (h)
TF2
CF2
*
* *
* * * *
0
0,2
0,4
0,6
0,8
1
0 3 6 9 12 15 18 21 24 27
Pro
po
rtio
n o
f th
e s
urv
ive
d a
nim
als
Time (h)
TF3
CF3
TF1 > CF1 TF2 > CF2
TF3 > CF3
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***
***
0
0,2
0,4
0,6
0,8
1
0 12 24 36 48
Pro
po
rtio
n o
f th
e s
uvi
ved
an
imal
s
Time (h)
TF1 CF1
***
***
0
0,2
0,4
0,6
0,8
1
0 12 24 36 48
Pro
po
rtio
n o
f th
e s
urv
ive
d a
nim
als
Time (h)
TF2 CF2
**
***
0
0,2
0,4
0,6
0,8
1
0 12 24 36 48
Pro
po
rtio
n o
f th
e s
uvi
ved
an
imal
s
Time (h)
TF3 CF3
TF1 > CF1 TF2 > CF2
TF3 > CF3
V. campbellii resistance
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Zn in O (P) and F3 generation
LC50 = 13.4 (6.6 - 15.7) mg/l
Heat shock (F3)
Non-heat shock (O)
Non-heat shock (F3)
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Phenotypic trait - HSP70 production
TP CP TF1 CF1 TF2 CF2 TF3 CF3
0
100
200
300
400
500
T-F0 C-F0 T-F1 C-F1 T-F2 C-F2 T-F3 C-F3
Hsp
70
(n
g/µ
g o
f p
rote
in)
Treatment
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Histone acetylation
Transcriptionally active
Transcriptionally repressed
HAT HDAC
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*
*
*
0
1
2
3
4
5
6
7
T-F0 C-F0 T-F1 C-F1 T-F2 C-F2 T-F3 C-F3
His
ton
e H
3 a
cety
lati
on
(n
g/µ
g o
f h
isto
ne
)
Treatment
Epigenetic mark - histone H3 acetylation
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TP CP TF1 CF1 TF2 CF2 TF3 CF3
0
0,3
0,6
0,9
1,2
1,5
T-F0 C-F0 T-F1 C-F1 T-F2 C-F2 T-F3 C-F3
His
ton
e H
4 t
ota
l ace
tyla
tio
n
(ng
/µg
of
his
ton
e)
Treatment
Epigenetic mark - histone H4 acetylation
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DNA methylation
Addition of methyl group to 5´ cytosine on CpG sites
Reduced chance of transcription
Silenced gene
DNA methylation
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*
*
0
0,1
0,2
0,3
0,4
0,5
T-F0 C-F0 T-F1 C-F1 T-F2 C-F2 T-F3 C-F3
%m
dc/
dG
Generations
Epigenetic mark – global DNA methylation
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Environmental heat stress on parental generation induces epigenetic inheritance of
resistance against disease, lethal heat shock and Zn
These transgenerational epigenetic inheritence of traits were associated with
production of HSP70 and sustained hyper-acetylation of histones H3 and H4
Abiotic environmental stimuli in parental generation can result in
transgenerational modification of phenotypes
Conclusions
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Future perspectives
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Thank you Acknowledgement
Promoter Prof. Dr. ir. Peter Bossier Funding BOF PhD Grant, UGent Belspo, AquaStress Project
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Cu in Wild population
LC50 = 0.18 (0.15 - 0.26) mg/l
LC50 = 0.26 (0.18 - 0.3) mg/l
Heat shock (W)
Non-heat shock (W)
axenic
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Zn in Wild population
LC50 = 10.6 (6.6 - 15.7) mg/l
LC50 = 4.6 (4.3 - 7.6) mg/l
Heat shock (W)
Non-heat shock (W)
axenic