一般口演

一般口演9

2021/10/1　13:00～14:00　オンデマンド D会場 O9-1 新しいミトコンドリア品質管理機構としてのミトコンドリア細胞外放出について Alternative mitochondrial quality control mediated by extracellular release ^○池中建介, Choong Chi-Jin, Hideki Mochizuki Department of Neurology, Osaka University Graduate School of Medicine ^○Kensuke Ikenaka, Choong Chi-Jin, Hideki Mochizuki Department of Neurology, Osaka University Graduate School of Medicine [Objective] Recent studies have shown mitochondria can cross cell boundaries and be transferred between cells. While the phenomenon has been extensively reported, its detailed mechanism and the resulting biological consequences remain unsolved. In this study, we tried to see how mitochondrial release are regulated under stress conditions and how it relates to the mitophagy regulations. [Methods] We developed the monitoring and quantifying system of released mitochondria from cultured cells. We observed how released mitochondria change, quantitatively or qualitatively, under treatment with drugs inducing mitochondrial stress. We also observed whether defect in mitophagy can alternate the mitochondrial release. Finally, we evaluated the amount of mitochondrial protein in biosamples obtained from patients and model animals. [Results] Rotenone- and CCCP-induced mitochondrial quality impairment promotes the extracellular release of depolarized mitochondria. Overexpression of parkin gene suppresses the extracellular mitochondria release under basal and stress condition, whereas its knockdown exacerbates it. Sera of PRKN-deficient mice contain higher level of mitochondrial protein compared to that of wild-type mice. More importantly, fibroblasts and cerebrospinal fluid samples from Parkinson disease patients carrying loss-of-function PRKN mutations show increased extracellular mitochondria compared to control subjects [Conclusions] Our findings suggest that extracellular mitochondria release is a comparable yet distinct quality control pathway from conventional mitophagy.		2021/10/1　13:00～14:00　オンデマンド D会場 O9-2 細胞内・外Aβレベル制御機構としてのエクソソーム：カニクイザル脳における老年性変化 Exosome secretion affects intracellular/extracellular Aβ levels: aging alters intraneuronal localization of exosomes in cynomolgus monkey brains ^○木村展之¹, Shingo Koinuma^1,2, Nobuhiro Shimozawa³, Yasuhiro Yasutomi⁴ 1.国立長寿医療研究センター, 2.Laboratory of Experimental Animals, Research and Development Management Center, National Center for Geriatrics and Gerontology, 3.Division of Biosignaling, Research Institute for Biomedical Sciences, Tokyo University of Science, 4.Tsukuba Primate Research Center, National Institutes of Biomedical Innovation, Health and Nutrition ^○Nobuyuki Kimura¹, Shingo Koinuma^1,2, Nobuhiro Shimozawa³, Yasuhiro Yasutomi⁴ 1.Section of Cell Biology and Pathology, Department of Alzheimer's Disease Research, Center for Development of Advanced Medicine for Dementia,National Center for Geriatrics and Gerontology, 2.Laboratory of Experimental Animals, Research and Development Management Center, National Center for Geriatrics and Gerontology, 3.Division of Biosignaling, Research Institute for Biomedical Sciences, Tokyo University of Science, 4.Tsukuba Primate Research Center, National Institutes of Biomedical Innovation, Health and Nutrition In Alzheimer’s disease (AD) brain, intraneuronal accumulation of Aβ precedes extracellular Aβ depositions. It remains unclear what accounts for this transition from intracellular to extracellular depositions. We previously found that autophagy affects extracellular release of Aβ via exosome secretion. Hence, we investigated the relationship of exosome secretion with Aβ metabolism in this study. In Neuro2a cells, knockdown of TSG101, which mediates intraluminal membrane vesicle (ILV) formation, significantly decreased extracellular release of Aβ and induced intracellular accumulation of Aβ. Rab27 mediates the trafficking of multivesicular bodies (MVBs) towards plasma membrane to excrete ILVs as exosomes into extracellular spaces. Rab27 knockdown clearly decreased exosome secretion, resulting in the prominent reduction of extracellular Aβ levels. We performed additional biochemical analyses by using primary rat cortical neurons to determine whether intracellular/extracellular Aβ levels correlate with exosome secretion in neurons. We confirmed that Rm-induced upregulation of autophagy strongly reduced exosome secretion, resulting in the intracellular accumulation of Aβ. Finally, we investigated age-related changes of exosome by using cynomolgus monkey brains. Alix levels did not change, however, immunohistochemical analyses revealed that intraneuronal localization of Alix-immunoreactive granules significantly altered in aged monkey brains. Double immunohistochemical analyses confirmed that the exosome marker proteins overlap spatially with amyloid plaques. Although it is just a situational evidence, these findings suggest that exosome secretion may mediate the transition of Aβ pathology from intracellular accumulation to extracellular deposition.

2021/10/1　13:00～14:00　オンデマンド D会場 O9-3 ビフィズス菌の加熱殺菌体は慢性社会的敗北ストレスにより誘発されるうつ様行動及びインターロイキン1βの発現を抑制する Heat-sterilized Bifidobacterium breve prevents depression-like behavior and interleukin-1β expression in mice exposed to chronic social defeat stress ^○和生國澤¹, Aika Kosuge¹, Yumika Sugawara¹, Katsuki Shinohara¹, Tsubasa Iida¹, Bolati Wulaer^2,3, Tomoki Kawai¹, Hidetsugu Fujigaki³, Yasuko Yamamoto³, Kuniaki Saito^2,3,4, Toshaka Nabeshima^2,4, Akihiro Mouri^1,4 1.藤田医科大学大学院保健学研究科レギュラトリーサイエンス部門, 2.Advanced Diagnostic System Research Laboratory, Fujita Health University Graduate School of Health Science, 3.Department of Disease Control and Prevention, Fujita Health University Graduate School of Health Sciences, 4.Japanese Drug Organization of Appropriate Use and Research (J-DO) ^○Kazuo Kunisawa¹, Aika Kosuge¹, Yumika Sugawara¹, Katsuki Shinohara¹, Tsubasa Iida¹, Bolati Wulaer^2,3, Tomoki Kawai¹, Hidetsugu Fujigaki³, Yasuko Yamamoto³, Kuniaki Saito^2,3,4, Toshaka Nabeshima^2,4, Akihiro Mouri^1,4 1.Department of Regulatory Science for Evaluation & Development of Pharmaceuticals & Devices, Fujita Health University Graduate School of Health Sciences, 2.Advanced Diagnostic System Research Laboratory, Fujita Health University Graduate School of Health Science, 3.Department of Disease Control and Prevention, Fujita Health University Graduate School of Health Sciences, 4.Japanese Drug Organization of Appropriate Use and Research (J-DO) Major depressive disorder (MDD) is a common and serious psychiatric disease that involves brain inflammation. Bifidobacterium breve is commonly used as a probiotic and was shown to improve colitis and allergic diseases by suppressing the inflammatory response. Heat-sterilized B. breve has beneficial effects on inflammation. We hypothesize, therefore, that this probiotic might reduce depression symptoms. We tested this is a mouse model of social defeat stress. C57BL/6J mice exposed to chronic social defeat stress (CSDS) for five consecutive days developed a mild depression-like behavior characterized by a social interaction impairment. CSDS also altered the gut microbiota composition, such as increased abundance of Bacilli, Bacteroidia, Mollicutes, and Verrucomicrobiae classes and decreased Erysipelotrichi class. The prophylactic effect of heat-sterilized B. breve as a functional food ingredient was evaluated on the depression-like behavior in mice. The supplementation started two weeks before and lasted two weeks after the last exposure to CSDS. Two weeks after CSDS, the mice showed deficits in social interaction and increased levels of inflammatory cytokines, including interleukin-1β (IL-1β) in the prefrontal cortex (PFC) and hippocampus (HIP). Heat-sterilized B. breve supplementation significantly prevented social interaction impairment, suppressed IL-1β increase in the PFC and HIP, and modulated the alteration of the gut microbiota composition induced by CSDS. These findings suggest that heat-sterilized B. breve prevents depression-like behavior and IL-1β expression induced by CSDS through modulation of the gut microbiota composition in mice. Therefore, heat-sterilized B. breve used as an ingredient of functional food might prevent MDD.		2021/10/1　13:00～14:00　オンデマンド D会場 O9-4 A152T変異による、興奮性神経細胞培養における神経興奮性の上昇 The A152T tau mutation increases neuronal excitability in purely excitatory neuronal culture ^○前田純宏¹, Hirokazu Tanabe¹, Setsu Endo¹, Hideyuki Okano¹ 1.Department of Physiology, Keio University School of Medicine, 2.Fujifilm, 3.blank spot, 4.blank spot ^○Sumihiro Maeda¹, Hirokazu Tanabe¹, Setsu Endo¹, Hideyuki Okano¹ 1.Department of Physiology, Keio University School of Medicine, 2.Fujifilm, 3.blank spot, 4.blank spot The intraneuronal accumulation of aggregated tau protein is a pathological hallmark of various neurological diseases, including Alzheimer’s disease (AD). Recently, non-aggregated tau protein is supposed to regulate neuronal excitability under stressed conditions like seizures and ischemia. More than 40 tau gene mutations are known to induce familial neurodegenerative diseases, called frontotemporal dementia with Parkinsonism with chromosome 17 (FTDP-17), indicating that tau dysfunction can trigger neurodegeneration. In addition to the FTDP-17 mutations, a new mutation, A152T, is reported to increase the risk to develop AD and regulate neuronal excitability in mouse models. To examine the effects of tau gene mutations on neuronal excitability in human neurons, we introduced A152T or P301S mutation to a control induced pluripotent stem cells (iPSCs) derived from a healthy donor and conjugated a fluorescent protein to tau using genome editing technology. First, we differentiated the iPSCs to cortical neuronal cells including both excitatory and inhibitory neurons. However, we could not observe any difference on the neuronal excitability of those iPSC-derived neurons. Next, we differentiated these iPSCs only to excitatory neurons using a transcription factor, Ngn2, and neuronal microRNA, miR9/9*/124. Then, we found that the A152T mutation increases the neuronal excitability and the association of tau and Fyn, a regulator of neuronal excitability. These data indicated that the A152T tau gene mutation increases the neuronal excitability in the culture of only excitatory neurons, in which condition may mimic the stressed condition because of the lack of inhibitory neurons, while the mixed culture system masked the effects possibly through inhibitory inputs.