student research day - Case Western Reserve University School of ...

Anthony C. Merlocco
CXCR4-eGFP mice in the cuprizone model: Characterization of CXCR4 positive cells in the adult mouse brain before
and during demyelination
Anthony C. Merlocco, Liping Liu, Lindsay Darnall, Dr. Richard M. Ransohoff
Neuroinflammation Research Center, Department of Neurosciences
Lerner Research Institute, Cleveland Clinic Foundation
Background–One key pathogenic attribute of multiple sclerosis is failure of
remyelination after CNS insult, which requires successful cellular signaling of
glial precursors for migration and proliferation. CXCR4 is a hemopoeitic
chemokine receptor shown to be involved in the neuropoeitic system with its sole
ligand, SDF1. Using transgenic CXCR4-eGFP mice we tested the hypotheses that
CXCR4 positive cells will expression stem cell markers and neurogenic markers
during demyelinating cuprizone treatment.
Methods and Results–Starting at a minimum of 8 weeks of age mice were fed ad
libitum 0.2% (w/w) cuprizone (Sigma-Aldrich Inc., St.Louis, MO) milled into
mouse chow for 1–5.5 weeks (CXCR4-eGFP::SDF1-mRFP1) or 1-6 weeks (wild
type C57BL/6) to induce chronic demyelination. Mice were anesthetized and
perfused transcardially and spinal cord and brain were rapidly dissected and
stored in 4% PFA at 4 o C. Scanning and confocal microscopy were used to image
tissues. During demyelination, CXCR4+ cell expression does not increase with
cuprizone but individual cells appear throughout the corpus callosum. CD45 cell
expression increases along corpus callosum, consistent with demyelination and
GFAP positive cell populations grossly expand in hippocampus, corpus callosum,
and ventricular zones. As well, CD133 expression is similar in double transgenic
and WT mice during curprizone treatment.
Conclusions– In CXCR4-eGFP postnatal mice, GFAP positive cell populations may
represent areas of active neurogenesis potentially as radial glial cells. During
demyelination, increased CXCR4+ cell expression occurs sparsely in the corpus
callosum and may represent neurogenesis or infiltrating peripheral blood
leucocytes. CXCR4 + /CD45 - cells increasing in the corpus callosum represent
microglia, neurons, or astrocytes. There are a several CXCR4 + /GFAP + cells
appearing in the corpus callosum at 2 weeks and 4.5 weeks of cuprisone
treatment which represent astrogliosis or neurogenesis. increases along corpus
callosum, consistent with demyelination and GFAP positive cell populations
grossly expand in hippocampus, corpus callosum, and ventricular zones.
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