神経筋疾患・脱髄 Neuromuscler diseases/demyelination
O2-9-6-1 Protrudinが関与する遺伝性痙性対麻痺の病態メカニズム Etiology of hereditary spastic paraplegia in association with protrudin ○白根道子1 ○Michiko Shirane1 九大・生医研・分子医科学1 Dept. Mol. Cell. Biol., Med. Inst. Bioreg., Kyushu Univ.1 Protrudin is a membrane protein that is a key regulator of intra-neuronal transport. The gene encoding ZFYVE27 (SPG33), a synonym of human protrudin, was mutated (G191V) in patients of hereditary spastic paraplegia (HSP), also known as spastic paraplegias (SPGs). Mutations in the genes encoding for spastin (SPG4), atlastin-1 (SPG3A), or REEP1 (SPG31) account for up to 50% of the HSPs. These proteins form complex and are localized to the endoplasmic reticulum (ER) in the neurons. In addition, they harbor hydrophobic hairpin domains that promote high-curvature ER tubule formation as well as the ER network formation, suggesting the significance of ER network in HSP pathogenesis. We investigated whether protrudin also forms a complex with SPGs and regulates ER morphology. We adopted a proteomic approach to identify proteins that physically associate with protrudin. We generated transgenic mice expressing epitope tagged-protrudin that is controlled under prion promoter. Protrudin-complex was isolated from brain extracts of the transgenic mice. LC-MS/MS analysis of the complex revealed that protrudin interacts with HSP-related proteins such as atlastin-1, KIF5, Reticulon-1, -3, -4, and REEP5. The interaction was confirmed by a co-immunoprecipitation assay. We next investigated the membrane topology around hydrophobic segments of protrudin. The protease sensitivity mapping and maleimide-PEG-binding assays revealed that three hydrophobic segments of protrudin form a hairpin structure. These results suggest that protrudin forms complex with HSP-related proteins atlastin-1 and REEP5 and contributes to regulation of ER network. In addition, G191V mutant of protrudin was defective in the protein turnover and was sensitive to the ER stress. From these results, protrudin is a critical cause of hereditary spastic paraplegia.	O2-9-6-2 成体マウスの社会的経験依存性ミエリネーション誘導 Restoration of social experience-dependent myelination after demyelination in adult mice ○牧之段学1, 井川大輔1, 鳥塚通弘1, 山室和彦1, 竹田友彦1, 辰巳晃子2, 奥田洋明2, 森田昌子2, 和中明生2, 岸本年史1 ○Manabu Makinodan1, Daisuke Ikawa1, Michihiro Toritsuka1, Kazuhiko Yamamuro1, Tomohiko Takeda1, Kouko Tatsumi2, Hiroaki Okuda2, Shoko Morita2, Akio Wanaka2, Toshifumi Kishimoto1 奈良県立医科大学・医・精神医学1, 奈良県立医科大学・医・第2解剖学2 Psychiatry, Nara Medical University, Kashihara, Nara, Japan1, Anatomy and Neuroscience, Nara Medical University, Kashihara, Nara, Japan2 Social experience-dependent myelination in the medial prefrontal cortex of mice occurs only during a juvenile period "critical period" in which oligodendrocytes and myelin substantially develop. We hypothesized that if myelin disappears in adult mice, which means the brain seemingly becomes a juvenile one, social experience regains the potential to alter myelination. Intriguingly, social experience-dependent myelination reoccurred after drug-induced demyelination even in adult mice while not in intact adult brains with complete myelination. Since myelination consolidates neuronal circuits and reduces the plasticity, we also examined the effect of social experience on neuronal plasticity in the medial prefrontal cortex after the drug-induced demyelination as described above. Behavioral analyses revealed that medial prefrontal cortex-dependent behaviors were highly amenable to social experience after the demyelination, but not in intact brains in adulthood. These results suggest that social experience-dependent plasticity is possibly manipulated by diminishing myelin formation implying a new approach "reset and rewire of the brain" for the remedy of schizophrenia, mood disorders, developmental disorders and multiple sclerosis with abnormal myelination in adult.
O2-9-6-3 Exploring the role of cathepsin C and cystatin F in demyelinating diseases ○Wilaiwan Wisessmith1,2, Takahiro Shimizu2, Kenji F. Tanaka3, Kazuhiro Ikenaka1,2 Department of Physiological Sciences, SOKENDAI1, Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences2, Department of Neuropsychiatry, Keio University, Tokyo, Japan3 Cathepsin C (CatC) or dipeptidyl peptidase I is a cysteine protease, which activates several peptides and protein substrates that are related to immune inflammatory processes. We previously found that expression of CatC is upregulated in microglia in chronic demyelinated lesions. Additionally, expression of its inhibitor, cystatin F (CysF), is also induced during early phase of demyelination, but ceased its expression in chronic demyelinating stage (Hamilton et al., 2008, Ma et al., 2011). We choose two different models to study CatC and CysF role in different demyelination phases. We generated mouse lines to manipulate CatC or CysF expression by using Flexible Accelerated STOP Tetracycline Operator Knock-in (FAST) system (Tanaka K.F. et al., 2010). Homozygotes of CatSTOPtetO (CatCSTOP/STOP) or CysFSTOPteO (CysFSTOP/STOP) knock-in mouse showed no expression of CatC or CysF, which can be considered as CatC or CysF knockdown. We introduced PLP4e allele into CatCSTOP/STOP or CysFSTOP/STOP mice to examine their effects on chronic demyelination. In addition, we also used experimental autoimmune encephalomyelitis (MOG-EAE) model for study in acute demyelination phase. In chronic phase, CatCSTOP/STOP::PLP4e/- mouse at 8 months old have milder symptom when compared with PLP4e/- mouse. In acute phase, CatC showed early expression at 1 week after MOG immunization. CysFSTOP/STOP mouse showed more severe symptoms than that of wild type mouse in the MOG-EAE model.	O2-9-6-4 Relationship between mutation load, EEG and cognitive functioning in patients with mitochondrial disease ○Heather Moore1, Roger G. Whittaker1,2, Doug M. Turnbull1, Grainne S. Gorman1 Newcastle University1, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Department of Clinical Neurophysiology, Royal Victoria Infirmary, Newcastle upon Tyne, NE1 4LP, UK2 Introduction: Mitochondria produce energy and are essential for maintaining healthy cell functioning. Mitochondrial tRNA gene mutations lead to energy dysfunction and cause mitochondrial disease. Neurological dysfunction is a common feature of mitochondrial disease and the brain has high energy requirements, making it particularly vulnerable to mitochondrial dysfunction. Extensive research has examined EEG in patients with mitochondrial disease presenting with epilepsy. However, very little research has considered brain dysfunction in the absence of epilepsy, the effect of mitochondrial DNA (mtDNA) mutation load on brain dysfunction, or its effects on cognition. Aims: To explore the relationship between mtDNA mutation load, resting surface EEG, and cognitive functioning in patients with mitochondrial disease. Methods: Resting EEG was recorded in 12 patients with mitochondrial disease, harbouring either the m.3243A>G and m.8344A>G mitochondrial tRNA gene mutations. Data derived from all EEG surface leads was extracted from four frequency wavebands; alpha, theta, fast theta, and delta. Urinary epithelial cells were used to measure percentage of mtDNA mutation load. ACE-R was used to measure cognitive ability and to screen for cognitive impairment. Regression analyses were used to explore the relationship between mtDNA mutation load, EEG wavebands, and ACE-R total score. Results: There was no significant correlation between mtDNA mutation load and ACE-R total score. There was no significant linear relationship between alpha, theta, fast theta and delta waves and ACE-R total score. mtDNA mutation load accounted for 38-54% of the variance in theta, fast theta, and delta wave activity. There was no significant correlation with alpha wave activity. Conclusion: EEG frequency correlates with disease burden and future work to evaluate this association in larger numbers of patients with mitochondrial disease and its possible effect on cognitive performance are warranted.

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