Giant axonal neuropathy (GAN) is an early-onset neurological disorder caused by mutations in the GAN

Proinflammatory mononuclear phagocytes (MPs) play a crucial role in the progression of multiple sclerosis (MS) and other neurodegenerative diseases. Despite advances in neuroimaging, there are currently limited available methods enabling noninvasive detection of MPs in vivo. Interestingly, upon activation and subsequent differentiation toward a proinflammatory phenotype MPs undergo metabolic reprogramming that results in increased glycolysis and production of lactate. Hyperpolarized (HP) 13 C magnetic resonance spectroscopic imaging (MRSI) is a clinically translatable imaging method that allows noninvasive monitoring of metabolic pathways in real time. This method has proven highly useful to monitor the Warburg effect in cancer, through MR detection of increased HP [1-13 C]pyruvate-tolactate conversion. However, to date, this method has never been applied to the study of neuroinflammation. Here, we questioned the potential of 13 C MRSI of HP [1-13 C]pyruvate to monitor the presence of neuroinflammatory lesions in vivo in the cuprizone mouse model of MS. First, we demonstrated that 13 C MRSI could detect a significant increase in HP [1-13 C]pyruvate-to-lactate conversion, which was associated with a high density of proinflammatory MPs. We further demonstrated that the increase in HP [1-13 C]lactate was likely mediated by pyruvate dehydrogenase kinase 1 up-regulation in activated MPs, resulting in regional pyruvate dehydrogenase inhibition. Altogether, our results demonstrate a potential for 13 C MRSI of HP [1-13 C]pyruvate as a neuroimaging method for assessment of inflammatory lesions. This approach could prove useful not only in MS but also in other neurological diseases presenting inflammatory components.hyperpolarized 13 C MR spectroscopy | multiple sclerosis | neuroinflammation | metabolism | macrophages M ultiple sclerosis (MS) is a multifaceted disorder of the CNS and is one of the most common causes of neurological disability in young adults (1, 2). Cortical and white-matter demyelination occurs early in MS pathogenesis and has been associated with disease progression and subsequent cognitive impairment (3). In the vast majority of cases, demyelinating lesions present a high inflammatory component, with elevated density of activated microglia/macrophages (mononuclear phagocytes, MPs) (4-6). Importantly, evidence suggests that proinflammatory MPs are one of the most abundant sources of reactive oxygen species (7), which mediate demyelination and axonal injury (8). Due to their central role in MS pathogenesis, noninvasive imaging of proinflammatory MPs would be of high importance for monitoring progression and response to antiinflammatory therapeutic approaches.Several recent studies have demonstrated that, upon activation and differentiation toward a proinflammatory phenotype, MPs undergo metabolic reprogramming toward enhanced glucose uptake and increased glycolysis (9-14). As for the Warburg effect observed in cancer cells, this augmented glycolysis takes place under aerobic conditions and results in the...

Many neurodegenerative disorders, including Parkinson’s, Alzheimer’s, and amyotrophic lateral sclerosis, are well known to involve the accumulation of disease-specific proteins. Less well known are the accumulations of another set of proteins, neuronal intermediate filaments (NFs), which have been observed in these diseases for decades. NFs belong to the family of cytoskeletal intermediate filament proteins (IFs) that give cells their shape; they determine axonal caliber, which controls signal conduction; and they regulate the transport of synaptic vesicles and modulate synaptic plasticity by binding to neurotransmitter receptors. In the last two decades, a number of rare disorders caused by mutations in genes that encode NFs or regulate their metabolism have been discovered. These less prevalent disorders are providing novel insights into the role of NF aggregation in the more common neurological disorders.

Histone deacetylases (HDACs) represent emerging therapeutic targets in the context of neurodegeneration. Indeed, pharmacologic inhibition of HDACs activity in the nervous system has shown beneficial effects in several preclinical models of neurological disorders. However, the translation of such therapeutic approach to clinics has been only marginally successful, mainly due to our still limited knowledge about HDACs physiological role particularly in neurons. Here, we review the potential benefits along with the risks of targeting HDACs in light of what we currently know about HDAC activity in the brain.

Dystonia is a movement disorder characterized by involuntary and repetitive co-contractions of agonist and antagonist muscles. Dystonia 6 (DYT6) is an autosomal dominant dystonia caused by loss-of-function mutations in the zinc finger transcription factor THAP1. We have generated Thap1 knockout mice with a view to understanding its transcriptional role. While germ-line deletion of Thap1 is embryonic lethal, mice lacking one Thap1 allele-which in principle should recapitulate the haploinsufficiency of the human syndrome-do not show a discernable phenotype. This is because mice show autoregulation of Thap1 mRNA levels with upregulation at the non-affected locus. We then deleted Thap1 in glial and neuronal precursors using a nestin-conditional approach. Although these mice do not exhibit dystonia, they show pronounced locomotor deficits ref lecting derangements in the cerebellar and basal ganglia circuitry. These behavioral features are associated with alterations in the expression of genes involved in nervous system development, synaptic transmission, cytoskeleton, gliosis and dopamine signaling that link DYT6 to other primary and secondary dystonic syndromes.