xCT/Slc7a11 deletion accelerates motor recovery and improves histological outcomes following cervical spinal contusion in mice
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1
Université de Namur, Belgium
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2
Vrije Universiteit Brussel, Belgium
xCT protein is the specific subunit of System xc-, a multi-proteic complex importing cystine into cell while releasing extracellular glutamate. Although xCT protein expression is detected in brain glial cells, its expression in the spinal cord and during spinal cord disorders remain elusive. The aim of this study is to characterize the contribution of xCT to functional and histological outcomes following SCI, using wild-type mice (xCT+/+) and genetically-invalidated mice (xCT-/-). In situ hybridization allowed to detect xCT mRNA in astrocyte subpopulations and in meningeal fibroblasts in the normal spinal cord. During the early phase of spinal cord injury, xCT mRNA could also be detected in microglial cells and overall mRNA levels were upregulated, peaking at 4 days post-injury. While both injured xCT+/+ and xCT-/- mice recovered partly their motor functions, xCT-/- mice recovered muscular grip strength as well as pre-SCI weight substantially faster than xCT+/+ mice. Histology of injured spinal cords revealed increased number of motor neurons in xCT-/- mice at multiple distances around lesion epicenter. As xCT has been demonstrated as a regulator of microglial function (Mesci et al., Brain, 2015), we assessed markers of microglial activation. At 2 weeks post-SCI, the number of type A Iba1+ cells was unexpectedly much higher in contused xCT-/- than in xCT+/+ spinal cords. Analysis of M1/M2 polarization showed that contused xCT-/- spinal cords contained higher mRNA levels of Ym1 and IGF-1 (M2) while lower levels of NOX2 and TNF-a (M1). Additionally, the number of astrocytes and oligodendrocytes were unchanged between the two injured groups. This study suggests that, following SCI trauma, an early xCT upregulation (if confirmed at the protein level) exacerbates microglia-driven inflammation and influences motor neuron survival.
Keywords:
spinal cord injury (SCI),
Slc7a11/xCT,
System xc-,
Microglia polarization,
astrocyte
Conference:
Belgian Brain Congress 2018 — Belgian Brain Council, LIEGE, Belgium, 19 Oct - 19 Oct, 2018.
Presentation Type:
e-posters
Topic:
NOVEL STRATEGIES FOR NEUROLOGICAL AND MENTAL DISORDERS: SCIENTIFIC BASIS AND VALUE FOR PATIENT-CENTERED CARE
Citation:
Sprimont
L,
Gilloteaux
J,
Bouchat
J,
Massie
A and
Nicaise
C
(2019). xCT/Slc7a11 deletion accelerates motor recovery and improves histological outcomes following cervical spinal contusion in mice.
Front. Neurosci.
Conference Abstract:
Belgian Brain Congress 2018 — Belgian Brain Council.
doi: 10.3389/conf.fnins.2018.95.00035
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Received:
09 Aug 2018;
Published Online:
17 Jan 2019.
*
Correspondence:
Prof. Charles Nicaise, Université de Namur, Namur, Belgium, 5000, Belgium, charles.nicaise@unamur.be