neuroimmunology-2017-posters-accepted-abstracts

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Page 38
ISSN:2171-6625
September 18-19, 2017 | Dallas, USA
4th International Conference on
NEUROLOGY AND NEUROIMMUNOLOGY
Background: Astrocytes have long been established as
sentinels for infection. Glial activation has downstream
effects on the blood-brain barrier and neurons. However,
for many years, astrocyte activation following host infection
was essentially limited to “astrogliosis”, with the occasional
addition of hypertrophy or atrophy. More recently, it has
become possible to quantify the degree to which astrocytes
are activated, and to discern which parameters are important
for astrocyte function.
Methods: To determine how infectious agents alter
astrocyte activation, we “mined” the archives at Tulane
National Primate Research Center to find matched tissues
from macaques infected with SIV (the parental virus of HIV),
Chikungunya, Dengue and Brucella. Paraffin embedded
cortical tissues were cut at 6 µm thickness and stained for
GFAP and Toll-like receptor 2 for morphometric analyses
and innate immune activation, respectively. Morphometric
analyses were performed using Neurolucida software.
Routine measures included cell body area, total arbor, arbor
volume, number of dendrites, bifurcations, process endings
and modified Sholl analyses.
Results: Bacterial infection (with Brucella melitensis)
induced increases in all the parameters indicated above.
In contrast, lentiviral infection induced decreases in the
measured parameters, with the exception of cell body area
in white matter, although that only occurred in animals with
active encephalitis. Two closely associated flavi viruses,
Chikungunya and Dengue, produced very different effects on
the astrocytes. Whereas Dengue infection induced increases
in all the parameters in white matter, Chikungunya induced
decreases in bifurcations and tips, with increases in process
volume in grey matter. Only cell body area was increased in
white matter.
Discussion: Astrocytes respond rapidly to host infection.
While it is not hugely surprising that glia respond differently
to bacteria and viruses, what was surprising was that even
very closely associated viruses induce different responses
in astrocytes. We are currently generating software to
differentiate astrocytes based on morphometric data.
e:
Who will guard; the guards themselves?
Andrew G MacLean, Joseph Ramsey, Olivia Purcell, Kim M Lee and Kevin B Chiu
Tulane University, USA
J Neurol Neurosci, 8:5
DOI: 10.21767/2171-6625-C1-003