HAL Id: hal-02331616
https://hal-normandie-univ.archives-ouvertes.fr/hal-02331616
Submitted on 24 Oct 2019
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D-serine is involved in the β-amyloid-related pathophysiology in Alzheimer’s disease
E Ploux, L. Gorisse, I Radzishevsky, H Wolosker, T Freret, J-M Billard
To cite this version:
E Ploux, L. Gorisse, I Radzishevsky, H Wolosker, T Freret, et al.. D-serine is involved in theβ-amyloid- related pathophysiology in Alzheimer’s disease. 14eme Colloque de la Société des Neurosciences, May 2019, Marseille, France. �hal-02331616�
0 0,2 0,4 0,6 0,8 1 1,2 1,4
300 400 500
WT (n=15) 5xFAD (n=17) 5xFAD/SR-‐/-‐ (n10)
fEPSP/PFV ra+o
S+mulus intensity (μA)
A
0 50 100 150 200 250 300 350 400 450
WT 5xFAD 5xFAD/SR-‐/-‐
nmol/gr Tissue
D-‐serine level 12 month-‐old
0 50 100 150 200 250 300 350 400 450
WT 5xFAD 5xFAD/SR-‐/-‐
nmol/gr Tissue
D-‐serine level 3-‐4 month-‐old
75 100 125 150 175 200 225 250 275 300
-15 0 15 30 45 60
WT (n=11) 5xFAD (n=17) 5xFAD/SR-/- (n=9)
fEPSP slope (% of baseline)
Time (min)
3-‐4 month-‐old
75 100 125 150 175 200 225 250 275 300 325 350
-15
WT (n=11) 5xFAD (n=13)
5xFAD/SR-‐/-‐ (n=11)
10-‐12 month-‐old
fEPSP slope (% of baseline)
Time (min)
0 15 30 45 60
#
Extracellular recording in CA1 stratum radiatum hippocampal slices from either 3-‐4 or 10-‐12 month-‐old mice (aEer electrical sFmulaFon of Schaffer collaterals)
• High frequency (HFS)-‐induced long-‐term potenLaLon (LTP):
-‐ TesFng sFmulaFon (average of 3 sFmulaFons at 0,1 Hz) for 15min baseline and then resumed for 60 min aEer condiFoning
-‐ CondiFoning : 1 electrical train of sFmulaFon at 100 Hz for 1 sec
• Isolated NMDAr-‐mediated fEPSPs (field Excitatory PostSynapLc PotenLals):
-‐ PresynapFc Fiber Volley (PFV) and field Excitatory PostsynapFc PotenFals (fEPSPs) were recorded and fEPSP/PFV raFo were calculated for Input/Output curves
-‐ Recording were performed (low magnesium supplemented medium with the non-‐NMDAr antagonist NBQX, 10µM) either before and 15 min aVer addiLon of D-‐serine (100 µM)
D-‐SERINE IS INVOLVED IN THE β-‐AMYLOID-‐RELATED PATHOPHYSIOLOGY IN ALZHEIMER’S DISEASE
1 Ploux E., Gorisse-‐Hussonnois L., 2 Radzishevsky I., 2 Wolosker H., 1 Freret T., 1 Billard J-‐M.
1 Normandie Univ, UNICAEN, INSERM, COMETE, GIP CYCERON, 14000 Caen, France
2 Department of biochemistry, Technion, Israel InsItute of Technology, Haifa, Israel
AcFvaFon of N-‐methyl-‐D-‐aspartate subtype of glutamate receptors (NMDAr), key regulators of funcFonal brain plasFcity and memory process, requires the binding of the co-‐agonist D-‐serine. The homeostasis of these receptors are affected by soluble oligomers of the beta-‐amyloid pepLde (Aßo) in Alzheimer´s disease (AD). Aßo toxic effects possibly pass through mechanisms involving D-‐serine since Aßo sFmulate in vitro the producFon of the co-‐agonist.
However, the actual in vivo contribuFon of D-‐serine in the funcFonal NMDAr-‐related deregulaFons mediated by Aßo is sFll unknown.
Spontaneous alternaFon test
-‐ 12 month-‐old mice were tested for working memory performances
-‐ Mice were let free to explore Y-‐
maze for 8-‐min and successive entry of the 3 arms of the maze was considered as an alternaFon
-‐ The percentage of alternaLon was calculated as follows: NB of alternaFons / (total NB of arms visited – 2) x 100
Hippocampal phenotype of the experimental groups
5xFAD and 5xFAD/SR-‐/-‐ display similar hippocampal level of Aßo
(only traces were observed in WT mice, used as negaIve control)
5xFAD/SR-‐/-‐ mice at both ages show markedly reduced hippocampal level of D-‐serine
(either compared to WT mice or 5xFAD)
Func+onal plas+city (HFS-‐induced LTP)
SR deleFon (5xFAD/SR-‐/-‐) reverses LTP deficits displayed in 5xFAD mice, both in 3-‐4 and 10-‐12 month-‐old animals
NMDAr ac+va+on (isolated synap+c poten+als)
No genotype difference of NMDAr acFvaFon is observed in basal condiFons (A)
Only WT and 5xFAD/SR-‐/-‐ mice show significant D-‐serine-‐induced increase in NMDAr acFvaFon (B)
Our results show that deleLon of serine racemase prevents, at least parLally, memory-‐related behavioral deficits observed in mice with prominent features of amyloïdogenesis. Besides, impairment of NMDAr-‐
dependent funcLonal plasLcity, indicated a significant contribuLon of D-‐serine in NMDAr-‐dependent β-‐
amyloid related pathophysiology of AD.
1 1
2
Working memory
SR deleLon (5xFAD/SR
-‐/-‐)
reverses working memory deficits displayed by 5xFAD
SR deleFon (5xFAD/SR-‐/-‐) parFally reverses reference memory deficits displayed by 5xFAD mice aEer a second spaFal learning
Spa+al learning, Flexibility, Reference memory
Contact :
eva.ploux@unicaen.fr
5xFAD and 5xFAD/SR-‐/-‐ mice display reduced spaFal
learning performances (compared to WT mice) 5xFAD mice display flexibility deficits (compared to WT mice), fully reversed in 5xFAD/SR-‐/-‐ mice
Learning Relearning
Probe-‐test1 Probe-‐test2
Unaltered reference memory in 5xFAD and 5xFAD/SR-‐/-‐ mice
Morris Water Maze
-‐ 12 month-‐old mice were trained to learn locaFon of hidden plaporm (through disFnct visual cues)
-‐ Learning (spaIal learning performance) and relearning (flexibility) session: 4 trials/day during 5 days (60 sec inter-‐trial interval)
-‐ Probe tests (spaFal reference memory performance): performed 48 aEer last trial of (respecFvely, learning and relearning session). Plaporm was removed and mice were free to explore the maze during 60 sec
Phenotype characterizaLon
• Hippocampal Aβ42 levels 3-‐4 months old mice (n=4 to 6 per group)
• Hippocampal D-‐serine levels 3-‐4 and 12 month old mice (n=6 for all groups)
Behavioral characterizaLon
5xFAD/SR
-‐/-‐?
♂
3
In this study, we wonder if D-‐serine contributes in vivo to NMDAr deregulaFons mediated by Aßo. Behavioral analysis combined to extracellular electrophysiological recordings at hippocampal synapses is conducted in the 5xFAD transgenic mice model of amyloïdogenesis displaying marked increase in Aßo rates. They are compared to 5xFAD animals in which the homozygous gene of the serine racemase (SR) that
synthesizes D-‐serine, has been jointly invalidated. B
fEPSP/PFV ra+o
0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6
WT 5xFAD 5xFAD/SR-‐/-‐
+ D-‐serine
+ D-‐serine + D-‐serine
0 100 200 300 400 500 600 700 800 900
Day 1 Day 2 Day 3 Day 4 Day 5
Swimming distance (cm)
WT 5xFAD 5xFAD/SR-‐/-‐
N=19
* ***
***
# # #
# # #
N=22 N=19
0 100 200 300 400 500 600 700 800 900
Day 7 Day 8 Day 9 Day 10 Day 11
Swimming distance (cm)
WT 5xFAD 5xFAD/SR-‐/-‐
# # #
* ***
***
N=19 N=18
N=22 WT
5xFAD -/-
5xFAD/SR 40
45 50 55 60 65
% Alternation
$ $
N=18 N=18 N=21
Electrophysiology
Mean + sem ; ANOVA repeated measures * p< 0.05 ; *** p< 0.001 ; ### p< 0.001
Mean + sem ; Univariate t-‐test : $ p<0.05 vs 50%
Mean + sem
ANOVA one-‐way No group effect Univariate t-‐test : $ p<0.05 vs 25%
KO Serine Racemase (SR-‐/-‐)
D-‐Serine L-‐Serine
2 3
# #
# #
N=19 N=19 N=22 N=19 N=19 N=22 N=19 N=18 N=22 N=19 N=18 N=22
#
Mean + sem
ANOVA one-‐way # p<0.05
Mean + sem
ANOVA one-‐way No group effect Mean + sem
ANOVA repeated measures # # p<0.01 Mean + sem
ANOVA one-‐way * p<0.05 Mean + sem
ANOVA one-‐way ** p<0,01
Univariate t-‐test : $ p<0.05 vs 25%
Mean + sem
ANOVA one-‐way * p<0.05
Mean + sem ; ANOVA repeated measures * p< 0.05 ; *** p< 0.001 ; ### p< 0.001
3-‐4 month-‐old 3-‐4 month-‐old
*** *** ***
Mean + sem
ANOVA one-‐way *** p<0.001 vs WT
WT
(C57Bl/6)
5xFAD
Ca²+
LTP
Memory process
D-‐serine
Glutamate
+
Morphology
NMDA Receptor
ää D-‐serine ?
Ca²+
LTP
Memory process Impaired
ää
Glutamate
Neurodegenerescence NMDAR
deregulaLon
Aβ oligomers
