Longitudinal MRI and 1H-MRS study of SCA7 mouse forebrain reveals progressive multiregional atrophy and early brain metabolite changes indicating early neuronal and glial dysfunction - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue PLoS ONE Année : 2024

Longitudinal MRI and 1H-MRS study of SCA7 mouse forebrain reveals progressive multiregional atrophy and early brain metabolite changes indicating early neuronal and glial dysfunction

Jean-Baptiste Pérot
Anna Niewiadomska-Cimicka
  • Fonction : Auteur
Emmanuel Brouillet
  • Fonction : Auteur
Yvon Trottier
  • Fonction : Auteur

Résumé

SpinoCerebellar Ataxia type 7 (SCA7) is an inherited disorder caused by CAG triplet repeats encoding polyglutamine expansion in the ATXN7 protein, which is part of the transcriptional coactivator complex SAGA. The mutation primarily causes neurodegeneration in the cerebellum and retina, as well as several forebrain structures. The SCA7 140Q/5Q knock-in mouse model recapitulates key disease features, including loss of vision and motor performance. To characterize the temporal progression of brain degeneration of this model, we performed a longitudinal study spanning from early to late symptomatic stages using high-resolution magnetic resonance imaging (MRI) and in vivo 1 H-magnetic resonance spectroscopy ( 1 H-MRS). Compared to wild-type mouse littermates, MRI analysis of SCA7 mice shows progressive atrophy of defined brain structures, with the striatum, thalamus and cortex being the first and most severely affected. The volume loss of these structures coincided with increased motor impairments in SCA7 mice, suggesting an alteration of the sensory-motor network, as observed in SCA7 patients. MRI also reveals atrophy of the hippocampus and anterior commissure at mid-symptomatic stage and the midbrain and brain stem at late stage. 1 H-MRS of hippocampus, a brain region previously shown to be dysfunctional in patients, reveals early and progressive metabolic alterations in SCA7 mice. Interestingly, abnormal glutamine accumulation precedes the hippocampal atrophy and the reduction in myo-inositol and total N-acetyl-aspartate concentrations, two markers of glial and neuronal damage, respectively. Together, our results indicate that non-cerebellar alterations and glial and neuronal metabolic impairments may play a crucial role in the development of SCA7 mouse pathology, particularly at early stages of the disease. Degenerative features of forebrain structures in SCA7 mice correspond to current observations made in patients. Our study thus provides potential biomarkers that could be used for the evaluation of future therapeutic trials using the SCA7 140Q/5Q model.
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Dates et versions

hal-04400325 , version 1 (17-01-2024)

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Jean-Baptiste Pérot, Anna Niewiadomska-Cimicka, Emmanuel Brouillet, Yvon Trottier, Julien Flament. Longitudinal MRI and 1H-MRS study of SCA7 mouse forebrain reveals progressive multiregional atrophy and early brain metabolite changes indicating early neuronal and glial dysfunction. PLoS ONE, 2024, 19 (1), pp.e0296790. ⟨10.1371/journal.pone.0296790⟩. ⟨hal-04400325⟩
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