Integrative Characterization of the R6/2 Mouse Brain Model of Huntington Disease Reveals Dysfunctional Neurotransmitter Metabolism

Huntington disease (HD) is a fatal neurodegenerative disease, where dysfunction and loss of striatal and cortical neurons are central to the pathogenesis of the disease. Here, we integrated quantitative studies to investigate the underlying mechanisms behind HD pathology in a systems-wide manner. To this end, we used state-of-the-art mass spectrometry (MS) to establish a spatial brain proteome from late-stage R6/2 mice and compared this to wild-type (WT) counterparts. From the quantitative analysis, we observed altered expression of proteins in pathways related to energy metabolism, synapse function, and neurotransmitter homeostasis. To support these findings, metabolic 13C labelling studies confirmed a compromised astrocytic regulation of glutamate-GABA-glutamine cycling resulting in impaired release of glutamine and GABA synthesis. In recent years increasing attention has been focused on the role of astrocytes in HD, and our data supports that therapeutic strategies to improve astrocytic glutamine metabolism may help ameliorate symptoms in HD.