NNS 2015 Abstract Book

with phospholipid analyses against internal standards and protein sam-

ples undergoing isobaric tagging for relative and absolute quantitation

(iTRAQ). Using Ingenuity Pathway Analysis software, datasets of signif-

icantly modulated proteins were mapped onto known molecular relation-

ships to determine the functional significance of the observed changes.

Results:

In our CCI model our data identify significant changes in the

expression of many proteins in the mouse hippocampus and cortex at

24 hrs, 1 month and 3 months after TBI, including proteins with signifi-

cantly different modulation in APOE3 compared to APOE4 mice. APOE-

dependent lipidomic changes are also evident in our r-mTBI model.

Conclusions:

In our different mouse models of TBI our datasets

clearly demonstrate APOE dependent responses to injury that may

represent targets for therapeutic intervention.

Keywords: lipidomics, proteomics, mild TBI, APOE

S05-03

NEUROPROTECTIVE AND ANTI-INFLAMMATORY THERA-

PIES FOR CNS INJURY BASED UPON APOLIPOPROTEIN-E

Michael Vitek

Duke Univ. Med. Ctr. and Cognosci, Inc., Neurology, Durham, USA

Humans are the only species to express multiple isoforms of apolipo-

protein-E. While best known as a risk factor for Alzheimer’s Disease,

APOE4 is also a risk factor for worse outcomes following Traumatic Brain

Injury (TBI). Compared with apoE2 and apoE3, the apoE4 protein is a

very poor anti-inflammatory/neuroprotective/neurotrophic agent. We

found that COG112/COG1410, small peptide mimetics of holo-apoE2/3

were potent anti-inflammatory agents in BV2-microglial cultures and

primary macrophage cultures from mice with different APOE back-

grounds. In collaboration with Laskowitz, Hoane, or James, we found

COG1410 to be neuroprotective in closed head injury, controlled cortical

impact and intracranial hemorrhage models in rodents. In collaboration

with Colton, we also found reduced inflammation, reduced amyloid and

neurofibrillary tangle pathologies, and reduced neuronal loss in the CVN

model of Alzheimer’s upon COG1410 treatment. In each model, behav-

ioral outcomes were significantly improved in COG1410 treated animals

versus their control counterparts. In addition to being active when ad-

ministered 2 hours after trauma, COG1410 also efficiently crossed the

blood brain barrier, even in naı¨ve animals. As a Protein Phosphatase 2A

activating drug or PAD, COG1410 displays a novel mechanism of action

that supports its anti-inflammatory activity and portions of its neuropro-

tective activity. These and other data support the concept that APOE4/

apoE4 is associated with loss of a neuroprotective function in TBI and AD.

Keywords: apolipoprotein-E, trauma, Alzheimer, Protein Phos-

phatase 2A

S06 Genetic Dissection of Locomotor Circuitry

S06-01

CONDITIONAL SILENCING OF PROPRIOSPINAL NEU-

RONS: HOPPING TO A NEW TUNE

David Magnuson

1,2

, Amanda Pocratsky

, Scott Whittemore

1,2

University of Louisville, Neurological Surgery, Louisville, USA

University of Louisville, Anatomical Sciences and Neurobiology,

Louisville, USA

Locomotor function in the intact animal, and recovery after injury is de-

pendent on spinal cord central pattern generating (CPG) circuitry that

produces the flexor/extensor, right/left, hindlimb/forelimb alternating pat-

tern of stereotypic stepping. Long propriospinal neurons that interconnect

the two spinal enlargements have been well-defined anatomically, and are

presumed to participate in locomotor activity, however, their role in CPG

activity remains a mystery. We are investigating the functional contribu-

tions of long ascending propriospinal neurons (LAPNs) in the spinal cord

using a conditional two viral vector system that allows specific neuron

populations to be silenced based solely on their anatomy. Targeted neurons

reversibly express enhanced tetanus neurotoxin (eTeNT) which proteolyt-

ically cleaves vesicle-associated membrane protein 2, and prevents exo-

cytosis of synaptic

vesicles.We

have targeted LAPNs with cell bodies at L2

and terminals at C6. Bilateral injections of HiRet-TRE-EGFP.eTeNT at C6

and tetracycline-responsive AAV2-CMV-rtTAV16 at L2 were performed

to doubly-infect LAPNs followed by defined periods of

ad libitum

doxy-

cycline (DOX, 15mg/ml in drinking water) to induce eTeNT expression.

Conditional silencing of the L2-C6 LAPNs induced a symmetrical,

rabbit-like gait resulting from the disruption of right/left alternation of both

forelimbs and hindlimbs, where both girdles moved in near synchrony.

Hopping was characterized by a significant increase in hip height dis-

placement, however there were no overt changes in the flexor/extensor

(intralimb) coordination. The phenotype was robust, reversible and re-

peatable and occurred in all animals silenced. Approximately 25–30% of

steps showed a disrupted right-left phase relationship during silencing. In-

terestingly, hindlimb alternation during swimming, a bipedal mode of lo-

comotion, was not disrupted by silencing the LAPNs. These results suggest

that L2-C6 LAPNs are critical components of the CPG circuitry mediating

right/left alternation in the intact animal. These data further suggest that

current models of locomotor circuitry need to include a half-center re-

sponsible for left/right control independent of rhythmgeneration. Supported

by GM103507, NS089324, and KSCHIRT 13-14 (DSKM, SRW).

Keywords: spinal cord, central pattern generator, propriospinal

neuron, conditional silencing, locomotion and gait

S06-02

TAKING A STEP TOWARDS MOTOR FUNCTIONAL RE-

COVERY AFTER SPINAL CORD INJURY: GENETICALLY

DEFINING SPINAL MICROCIRCUITS

Robert Brownstone

Dalhousie University, Surgery (Neurosurgery), Halifax, Canada

Neural circuitry that produces the basic rhythm and pattern of locomotion

is situated in the spinal cord. Following spinal cord injury, locomotor

training can lead to significant improvement in gait. The mechanisms

underlying this neural plasticity are unknown. In this talk, I will discuss

how genetic techniques have provided a window through which to study

spinal motor circuits and their plasticity. I will first discuss spinal regu-

lation of hand grasp, and then spinal control of walking, outlining a circuit

important for recovery of function after injury. Understanding mecha-

nisms of spinal plasticity is important for the further development of

strategies aimed at improving motor function following spinal cord injury.

Keywords: locomotion, neural plasticity, grasp, microcircuits

S06-03

MUSCLE SPINDLE FEEDBACK DIRECTS LOCOMOTOR

RECOVERY AND CIRCUIT REORGANIZATION AFTER

SPINAL CORD INJURY

Aya Takeoka

1,2

, Isabel Vollenweider

, Gregoire Courtine

, Silvia

Arber

1,2

Friedrich Miescher Institute for Biomedical Research, Neurobiology,

Basel, Switzerland

Biozentrum, University of Basel, Cell Biology, Basel, Switzerland

Ecole Polytechnique Fe´de´rale de Lausanne, Brain Mind Institute and

Centre for Neuroprosthetics, Lausanne, Switzerland

Spinal cord injuries alter motor function by disconnecting neural cir-

cuits above and below the lesion, rendering sensory inputs a primary

A-140