Presented at UH Undergraduate Research Day 2015.

1. CONCLUSIONS
EXPERIMENTAL DESIGN
Survival Frequency Open Field Test
Adenosine Analog Reduces Mortality and Autistic-
like Comorbidities in Dravet Syndrome Model
L. Montier, C. Riffe, C. Upchurch, F. Gu, and J. Žiburkus
Department of Biology and Biochemistry, University of Houston, TX 77204
Dravet syndrome (DS) is a severe form of childhood-onset epilepsy. Affected
children experience recurrent seizures, lifelong social and cognitive
dysfunctions, and high mortality rates. According to 2011 studies, 24.3% of
DS patients meet the criteria for autism1 and 10.1% will suffer DS-related
deaths2. Mutations in the SCN1A gene, which codes for voltage-gated sodium
channels, account for up to 80% of DS cases. These channels play a key role
in a neuron’s ability to conduct electrical signals. Transgenic mice that
express a SCN1A gene mutation recapitulate many aspects of human DS. The
Ziburkus lab has shown promising results in acutely controlling seizures in a
DS mouse model through the use of adenosine A1 receptor agonist N6-
cyclopentyladenosine (CPA). We tested the ability of a 10-day CPA treatment
during early development to reduce mortality and to rescue dysfunctional
social, learning, and anxiety behavior. We observed a 51% decrease in
mortality, improved sociability, and restored hippocampal-based long-term
memory. This could be due to reduced seizure incidence during early
development. Because not all behavioral comorbidities were abated by the 10-
day treatment, the goal of our current study is to reduce hyperactivity and
anxiety and to fully restore normal social patterns by extending the treatment
to 20 days. Overall, the study is highly translational and if successful, could
lead to additional studies of adenosine in human DS patients.
Hypothesis: In addition to decreasing the adolescent seizures associated
with DS, chronic treatment with adenosine A1 receptor agonist CPA
during development will prevent cognitive and behavioral dysfunctions.
BACKGROUND
CPA treatment Open field 3-chamber
Fear
conditioning
10 wks9 wks8 wksP20/
P30
P11
Adenosine A1 receptor agonist N6-cyclopentyladenosine (CPA) (0.05mg/kg) was
injected intraperitoneally every 12 hours from P11 to P20 or from P11 to P30.
Timeline of adenosine treatment and behavioral tests.
0.00
0.20
0.40
0.60
0.80
1.00
0 2 4 6 8 10
Weeks
A. Untreated Mice
WT SCN1A +/-
0.00
0.20
0.40
0.60
0.80
1.00
0 2 4 6 8 10
Weeks
B. 10-day CPA Treated Mice
WT SCN1A +/-
0.00
0.20
0.40
0.60
0.80
1.00
0 1 2 3 4 5 6 7 8 9 10
Weeks
C. 20-day CPA Treated Mice
WT SCN1A+/-
TECHNIQUES and RESULTS
Adenosine
administration
during early age
reduces Dravet
syndrome-related
death. (A) At 10
weeks of age, only
12 out of 26, or 33%,
untreated SCN1A +/-
mice were alive. (B)
CPA treatment from
P11-P20 increased
survival of SCN1A +/-
mice to 26 out of 31,
or 84%, at 10 weeks
of age. (C) CPA
treatment from P11-
P30 increased
survival of SCN1A+/1
mice to 16 out of 27,
or 59%, at 10 weeks
of age.
(A) SCN1A+/- mice exhibit hyperactivity. (B) SCN1A+/- mice exhibit
increased anxiety. (C) Visual sample of mouse’s movement trajectories. Left:
movement of untreated WT. Right: movement of untreated SCN1a+/-.
Three-chamber Sociability Test
Empty
2
Stranger
Mouse #1
(M1)
Center
Subject
Mouse
B. Stranger #1
Stranger
Mouse #2
(M2)
Stranger
Mouse #1
(M1)
Center
Subject
Mouse
C. Stranger #2
Empty 2Empty 1 Center
Subject
Mouse
A. Control
(A) Mice do not show an intrinsic preference for any chamber. (B) Twenty day CPA treatment restores normal sociability in
SCN1A+/- mice. (C) CPA-treated WT mice do not prefer social novelty. SCN1A+/- mice do not prefer social novelty.
REFERENCES
ACKNOWLEDGEMENTS
A.
C.
B.
Contextual Fear Conditioning Test
Saline-treated SCN1A+/- mice exhibit reduced learning as
compared to WT mice. Ten day CPA treatment improves learning
in SCN1A +/- mice, but reduces learning in WT mice. Twenty day
CPA treatment does not significantly affect learning in either WT
or SCN1A +/- mice.
Subject mouse is placed in an enclosed chamber with a shock grid
floor. A 10 second, 0.7 mA foot shock is administered three times
at equal intervals during 7.5 minutes in the chamber. 24 hrs later,
the subject mouse is returned to the chamber for 7.5 minutes,
but is not exposed to a shock. Increased ‘freezing’ behavior
indicates long-term associative learning.
Assessment of locomotor activity and anxiety-like behavior. Subject
mouse is placed in center of arena, and its activity is recorded for ten
minutes. Anxiety-prone mice spend more time in the margin of the
arena rather than in the unprotected center area.3
1. Li BM, Liu XR, Yi YH, et al. Autism in Dravet syndrome: Prevalence, features, and relationship to the
clinical characteristics of epilepsy and mental retardation. Epilepsy & Behavior. 2011; 21: 291-295.
2. Sakauchi M, Oguni H, Kato I, et al. Retrospective multiinstitutional study of the prevalence of early
death in Dravet syndrome. Epilepsia. 2011; 52: 1144–1149.
3. Bailey KR, Crawley JN. Anxiety-Related Behaviors in Mice. In: Buccafusco JJ, ed. Methods of Behav.
Anal. in Neuro. 2nd ed. Boca Raton, FL: CRC Press; 2009. Chapter 5.
4. Woodgett JR, Kaidanovich-Beilin O, Lipina T, Vukobradovic I, Roder J. Assessment of Social
Interaction Behaviors. J Vis Exp. 2011; 48: 2473.
 Sub-chronic administration of CPA in early development increases survival frequency
in a mouse model of Dravet syndrome.
 CPA treatment from post-natal day 11-20 improves learning in SCN1A+/- mice, but
has a negative effect on WT mice. CPA treatment from post-natal day 11-30 does not
improve learning in Dravet mice.
 CPA treatment from post-natal day 11-30 restores normal sociability in Dravet mice.
 Adenosine administration at early age could possibly be used to treat intractable
forms of epilepsy and associated comorbidities. However, the most effective
treatment timeline remains unclear.
This research is supported by Dravet Syndrome Foundation (J.Ž.), University of Houston
SURF 2013, PURS 2014 (C.R.) and Biology of Behavior Institute (F.G. and L.M.) programs.
Institutional approvals
All of the experiments followed protocols approved by UH IACUC committee.
Propensity to spend time with the stranger mouse, as compared to time spent alone, indicates normal sociability. Propensity
to spend time with a previously unencountered mouse rather than with a familiar mouse indicates a preference for social
novelty.4