Page 135 - NNS 2014 Program & Abstract Book

D1-07
INTERACTIONS BETWEEN PIOGLITAZONE AND MITO-
NEET AMELIORATE MITOCHONDRIAL DYSFUNCTION
FOLLOWING TRAUMATIC BRAIN INJURY
Yonutas, H.M.1, Pandya, J.D.1, Sebastian, A.H.1, Geldenhuys, W.J.2,
Carroll, R.T.2, Sullivan, P.G.1
1University of Kentucky, Lexington, United States
2Northeastern Ohio University, Rootstown, United States
A major pursuit is currently underway for the discovery of novel
neuroprotective therapeutic agents to help those suffering from trau-
matic brain injury, TBI. Due to the complicated nature of TBI, the
most promising compounds target multiple mechanisms initiated
following injury such as neuroinflammation, ROS production and
mitochondrial dysfunction. Previous reports show that pioglitazone, a
known PPAR agonist, can alter neuroinflammation and decrease ROS
production. Additionally, pioglitazone has been found to increase
mitochondrial bioenergetics, cortical sparing and functional recovery
following TBI, which aligns with our theory that mitochondrial dys-
function is a pivotal link in the neuropathological sequelae of brain
injury. The positive effects seen with pioglitazone seem to be inde-
pendent of PPAR interaction and may be attributed to its binding
affinity with a novel mitochondrial protein called mitoNEET.
Therefore, we hypothesize that pioglitazone’s neuroprotective mech-
anism is dependent on interactions with mitoNEET. To test this hy-
pothesis we have used mitoNEET null mice and a novel mitoNEET
ligand called NL-1. Ex vivo dose response studies show that
pioglitazone can increase mitochondrial bioenergetics in isolated
mitochondria with and without Ca2 + insult. Next, wild-type and mi-
toNEET null mice (pioglitazone and NL-1 study) and Sprague Dawley
rats (NL-1 study) who were subjected to sham or severe controlled
cortical impact (CCI) TBI surgery. Results demonstrate that piogli-
tazone loses its ability to increase mitochondrial respiration and
provide neuroprotection in mitoNEET null mice and that treatment
with a specific mitoNEET ligand (NL-1) increases cortical sparing
and motor recovery following TBI. Therefore, we believe pioglita-
zone to be a novel mitochondrial targeting drug which is able to alter
mitochondria bioenergetics following TBI through interactions with
mitoNEET. Results from these studies will help to shed light on the
fundamental processes involved in TBI neuropathology and may
pinpoint potential novel interventions and targets for the treatment of
TBI.
Key words
controlled cortical impact, mitochondria, mitoNEET, pioglitazone,
traumatic brain injury
D1-08
EFFECT OF NNZ-2591 TREATMENT ON AXONAL AND SY-
NAPTIC PLASTICITY FOLLOWING PENETRATING BAL-
LISTIC-LIKE INJURY IN RATS
Deng-Bryant, Y., Caudle, K., Leung, L.Y., Winter, M., Yang, X.,
Cartagena, C., Boutte, A., Schmid, K., Shear, D.A., Tortella, F.C.
Walter Reed Army Institute of Research, Silver Spring, USA
NNZ-2591, a novel diketopiperazine, has shown therapeutic effects in
improving sensorimotor and cognitive outcome in rodent models of
neurodegenerative diseases. The current study examined the potential
role of NNZ-2591 in neuroplasticity following penetrating ballistic-
like injury (PBBI; 10% injury severity) in rats. Adult Sprague-Dawley
rats were randomly assigned into three groups: sham (craniotomy
only), PBBI + vehicle (i.e. H 2O), and PBBI + NNZ-2591. NNZ-2591
(or vehicle) was administered via oral gavage at 30 mg/kg at 30 min
post-injury and continued once daily thereafter for 7, 14 or 28 days.
At each treatment endpoint, rats were perfused and brains were pro-
cessed for histological analysis (n = 4-6/group/time-point). For de-
tection of axonal sprouting, immunohistochemical detection of
growth-associated protein-43 (GAP-43) was employed. Synaptogen-
esis was determined by immunohistochemistry for synaptophysin
(SYN). For histological quantification, the integrated density in the
hippocampal region was determined using NIH ImageJ software. In
the vehicle treatment group, PBBI significantly decreased GAP-43
expression in the ipsilateral hippocampus at 7 d, 14 d and 28 d post-
injury, and in the contralateral hippocampus at 7 d and 14 d post-
injury (p < 0.05 vs. sham). Significant reductions in SYN staining were
detected at 14 d and 28 d post-injury in the ipsilateral hippocampus
and at 14 d post-injury in the contralateral hippocampus in the
PBBI + vehicle group (p < 0.05 vs. sham). Continuous treatment with
NNZ-2591 showed no effect on injury-induced reductions in GAP-43
or SYN expression at 7 d or 14 d post-PBBI. However, at 28 d post-
injury, NNZ-2591 treatment attenuated PBBI-induced reductions in
both GAP-43 and SYN expression to levels that did not differ sig-
nificantly from sham controls, indicative of an intermediate treatment
effect. Overall, the histological analysis indicates that PBBI induced
significant reduction of axonal sprouting and synaptogenesis during
sub-acute to chronic phase after injury. Furthermore, the current re-
sults show a promising trend of NNZ-2591 in promoting neuroplas-
ticity and warrant further testing of this drug using extended treatment
durations in the PBBI model.
Key words
axonal sprouting, diketopiperazine, synaptogenesis
D1-09
EVALUATION OF COMBINED ADMINISTRATION OF
DEXTROMETHORPHAN AND SIMVASTATIN IN AN EX-
PERIMENTAL MODEL OF TRAUMATIC BRAIN INJURY
Shear, D.A.1, Caudle, K.L.1, Mountney, A.1, Deng-Bryant, Y.1,
Pedersen, R.1, Sun, J.1, Schmid, K.1, Lu, M.1, Tallarida, R.J.2,
Tortella, F.C.1
1Walter Reed Army Institute of Research, Silver Spring, MD
2Temple University School of Medicine, Philadelphia, PA
We recently completed comprehensive Phase I monotherapy dose-
response (D-R) testing of Dextromethorphan, Progesterone, Simvas-
tatin and Cyclosporine in a rat model of penetrating ballistic-like brain
injury (PBBI). Of the 4 drugs tested, Dextromethorphan (DM) showed
the most consistent D-R profile across motor parameters whereas
Simvastatin (SIM) showed the best D-R profile for improved cogni-
tive outcome. In this study, isobolographic analysis (based on the
concept of dose equivalence) was used to construct fixed-dose ratios
of each drug to determine whether combined treatment produce ad-
ditive or synergistic effects. Anesthetized rats received frontal PBBI
(10% injury severity). DM and SIM were tested in pairs at the fol-
lowing fixed-dose ratios: 1.65/0.0019 mg/kg, 3.3/0.0038 mg/kg, 6.59/
0.015 mg/kg or 13.19/0.150 mg/kg (DM/SIM, respectively). DM was
administered at 30 m, 2 h, 4 h, and 6 h post-PBBI and once/day for
3 consecutive days. SIM was administered at 30 m and 6 h post-PBBI
and once/day for 10 consecutive days. Motor and cognitive abilities
were assessed using the rotarod and Morris water maze (MWM). In
addition to being analyzed individually, the primary outcome metrics
were transformed into standardized z-scores and summed to yield a
A-103