NNS 2015 Program & Abstract Book

C7-24

ANTIBODY-MEDIATED AUTOIMMUNITY AFTER CERVI-

CAL SPINAL CORD INJURY: DISTINCT ROLES FOR IGG

AND IGM

Antigona Ulndreaj

1,2

, Apostolia Tzekou

, Andrea Mothe

, Charles

Tator

1–3

, Emina Torlakovic

, Michael Fehlings

1–3

University of Toronto, Institute of Medical Science, Toronto, Canada

Toronto Western Hospital, Krembil Neuroscience Center, Toronto,

Canada

University of Toronto, University of Toronto Spine Program, Tor-

onto, Canada

University of Toronto, Department of Laboratory Hematology, Tor-

onto, Canada

Generation of autoantibodies has emerged as an important component

in the pathophysiology of spinal cord injury (SCI) and was shown to

impair functional recovery in low thoracic SCI models. However, the

development of autoantibodies and their role in the outcome of cer-

vical SCI has not been described. The objective of this study was to

determine whether autoantibodies of the IgG and IgM class are gen-

erated after cervical SCI in a rat model of contusion/compression

injury. A C7/T1 clip injury was induced in Wistar rats, whereas sham

animals received only a laminectomy. Samples were collected at 2, 10

and 20 weeks post injury. Spinal cords and spleens were stained for

IgM and IgG antibodies. Levels of total antibodies in serum were

quantified with ELISA. Our results demonstrated increased binding of

IgG and IgM in the gracile fasciculus, at 2 weeks post injury. In

addition, IgG showed increased binding in the anterior white com-

missure. Importantly, we detected IgG

cells that were reminiscent of

antibody secreting cells (ASCs), suggesting intraspinal IgG synthesis.

Moreover, at 20 weeks, we detected high levels of IgG and IgG

ASCs in the dorsal horn of injured rats. Despite the chronic presence

of IgG in the spinal cord, systemic levels of IgG antibodies and

splenic IgG

ASCs declined after injury. Contrary, systemic IgM

immunity was pronounced as we detected higher levels of serum IgM

and higher IgM

ASCs in the spleen of injured rats. Overall, our data

indicate that IgG autoantibodies persist in the spinal cord, whereas

IgM antibodies persist peripherally in SCI animals. This work has

important implications for our understanding of the key immunolog-

ical changes after cervical SCI.

Keywords: Spinal cord injury, Autoimmunity, IgM, IgG immuno-

globulins

C7-25

EVALUATION OF POLYUNSATURATED FATTY ACID DE-

RIVED MEDIATORS OF INFLAMMATION TO AMELIO-

RATE PRIMARY BLAST WAVE INJURIES IN RATS

James DeMar

, Miya Hill, Donna Wilder, John Rosenberger, Meghan

Mccuistion, Joseph Long

Walter Reed Army Institute of Research, Center for Military Psy-

chiatry and Neuroscience Research, Silver Spring, USA

Blast injury is arguably the greatest current threat to Warfighters, and

is a leading cause of vision loss from non-penetrating trauma to the

eyes or brain, caused by the shock waves. In light of the terrible

disability loss of vision presents, there is an urgent need for new drug

therapies that can ameliorate neurodegeneration in the eyes (retina)

and brain as the result of blast wave exposure. Our hypothesis is that

metabolites of polyunsaturated fatty acids, known to be potent pro-

resolving mediators of inflammation, i.e., lipoxins, neuroprotectins,

and resolvins, will aid as drugs to promote healing of neurons critical

to visual function after blast injury. In a rat model of blast wave

exposure, we have used electroretinography (ERG), visual discrimi-

nation behavior, and histopathology to show, by 14 days post-blast,

visual dysfunction occurs along with underlying neurodegeneration of

the retinas and brain optic tracts. Blast injury was produced in an-

esthetized rats that were secured in a compressed air driven shock tube

and then exposed to a single blast over pressure wave (20 psi, 8 msec).

For therapeutic drug evaluations, rats received one of four com-

pounds, lipoxin A4, protectin DX, resolvin D1, and resolvin E1

12), which was intravenously administered immediately post-

insult and then every other day out to 14 days. Likewise, shams and

blasted controls were given saline. Retina and brain status were as-

sessed as found above. Surprisingly, our results suggest these drugs

provide slight, if any, neuroprotection towards the blasted rat’s visual

system. Failure of our approach may be due to ineffective drug de-

livery to neuronal injury sites from systemic dilution, transient half-

lives, and poor penetration of the blood brain retinal barriers. These

obstacles might be overcome using tissue targeted drug delivery

platforms, e.g., nanoparticles, which if successful will provide an

important therapeutic tool for blast injuries.

Keywords: Blast wave, Rat, Eye, Retina, Brain, Polyunsaturated

Fatty Acids

C7-26

ACUTE AND SUBACUTE MICRORNA MODULATION FOL-

LOWING PBBI

David Johnson

, Angela Boutte, Kara Schmid, Jitendra Dave, Frank

Tortella, Casandra Cartagena

Walter Reed Army Institute of Research, Psychiatry and Neu-

roscience, Silver Spring, USA

MicroRNAs (miRNAs) are small regulatory RNAs that have recently

been exploited as potential biomarkers for several diseases. These

RNAs regulate several physiological processes through translational

repression or degradation. In this study we investigated novel

miRNA changes in our severe penetrating ballistic-like brain injury

(PBBI) model. Briefly, this model produces a cavity disrupting 10%

of brain volume in injured rats, while a craniotomy is produced in

sham controls. Ipsilateral brain tissue and serum were collected (4h,

1d, 3d, 7d) post injury or post sham to examine miRNAs (n

10 per

group). Each animal was run as an independent single array. Our

reporting was limited to miRNAs with p value

0.05 and 1.2 fold

(20%) or greater change. At 4h, 4 miRNAs were downregulated and

19 miRNAs were upregulated. At 1d post PBBI 3 miRNAs were

attenuated and 4 miRNAs were significantly enhanced. At 3d post

injury, 5 miRNAs were decreased and 2 were increased. Seven days

post PBBI revealed 9 attenuated miRNAs and surprisingly over 30

were significantly enhanced. Of the miRNAs changed in tissue

8 miRNAs were changed across at least 2 time points including

miR-147b, miR-21#, miR- 223, miR-142-3p, miR-142-5p, miR-21,

miR-685, miR-34b-5p. These identified miRNAs will be utilized as

injury markers in the evaluation of prospective therapeutics. In se-

rum 5 miRNAs were decreased 4h, 6 miRNAs decreased and 1

miRNA increased at 1d, 2 miRNAs decreased and 8 were increased

at 3d, and 5 miRNAs were decreased and 2 miRNAs were increased

at 7d. Of the altered miRNAs in serum, 1 corresponded with changes

in tissue, miR-150. These altered serum miRNAs will be further

evaluated for their usefulness as clinically relevant prognostics or

theragnostics.

Keywords: microRNA, TBI, Array

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