公募シンポジウム

公募シンポジウム長時間計測が拓く新たな脳機能・病態研究

7月8日（土）　13:50-15:50　Room C 3SY④-1 タウのダイナミクスから読み解く神経の生理と病理 Physiology and pathology of neurons as deciphered from the dynamics of Tau 坂内　博子早稲田大学　理工学術院 Hiroko Bannai FSE, Waseda Univ. Tauopathy is a neurological disorder caused by tau degeneration as exemplified by Alzheimer's disease. In such patients, tau proteins are denatured by excessive phosphorylation to form cytotoxic oligomers, which leads to the formation of pathological tau fiber formation. In vitro experiments have shown that tau is a protein capable of liquid-liquid phase separation (LLPS), and tau oligomerization and tau seed formation have been shown to occur in droplets of tau LLPS. However, the mechanism and timing of the formation of toxic tau oligomers and tau seeds in cells remain unclear. The difficulty in studying tau is that the time spent forming tau seeds and tau aggregates (decades in humans and months in model mice) is much longer than the time scales typically used for live cell imaging (milliseconds to days), and it is impossible to predict when and where tau oligomers and tau seeds are produced in the cell. Here, we present an optogenetic tool that can induce a specific form of tau. Using the cells expressing this optogenetic tool, we showed that tau LLPS, aggresomes, and tau seeds were induced by irradiating them with light under various conditions. By using this optogenetic tool to induce tau oligomers and tau seeds in cells at targeted times, it will be possible to elucidate the detailed process of tau aggregation in living cells, which was previously possible only in vitro.		7月8日（土）　13:50-15:50　Room C 3SY④-2 シナプス可塑性における“短時間-長時間”シグナル変換機構 Conversion mechanisms from short-term to long-term signaling in synaptic plasticity 村越　秀治生理学研究所 Hideji Murakoshi National Institute for Physiological Sciences Synaptic plasticity is considered to be the neural basis of long-lasting memory. Increased spine volume and molecular remodeling are crucial for synaptic plasticity, referred to as structural long-term potentiation (sLTP). In recent decades, there has been speculation about the necessity of long-term Ca²⁺/Calmodulin-dependent kinase II (CaMKII) activation for sLTP, but no definitive conclusion has been reached yet. To better understand CaMKII activity and function, we have developed a genetically encoded, light-inducible CaMKII inhibitor (paAIP2) that can regulate CaMKII activity with high temporal resolution. By combining paAIP2 with the 2-photon glutamate uncaging method, which has been demonstrated to induce sLTP in hippocampal neurons, we found that a brief activation period (~ 1 min) of CaMKII is sufficient for sLTP induction. Additionally, we have recently developed a genetically encoded photoactivatable CaMKII and found that the activation of CaMKII within the dendritic spine alone is enough to induce synaptic plasticity. Furthermore, using 2-photon fluorescence lifetime imaging microscopy, we revealed that short-term CaMKII activation converts into long-term Cdc42 activation and sLTP. Here, we will also present our recent attempts to develop novel fluorescent probes to elucidate the mechanism of signal conversion from short-term to long-term.

7月8日（土）　13:50-15:50　Room C 3SY④-3 新規ナノ薄膜を活用したマウス脳の長期的かつ広視野in vivo二光子イメージング In vivo long-term imaging of a mouse brain through a large cranial window utilizing PEO-CYTOP nanosheet 高橋　泰伽^1,2,3,11, 張　宏^4,5, 揚妻　正和^6,7, 鍋倉　淳一^3,6, 大友　康平^1,2,8, 岡村　陽介^4,9,10, 根本　知己^1,2,3 1. 生命創成探究センターバイオフォトニクス研究グループ, 2. 生理学研究所バイオフォトニクス研究部門, 3. 総合研究大学院大学, 4. 東海大学マイクロ･ナノ研究開発センター, 5. 天津大学化工学院, 6. 生理学研究所生体恒常性発達研究部門, 7. 量子生命科学研究所量子再生医工学研究チーム, 8. 順天堂大学大学院医学研究科, 9. 東海大学工学部応用化学科, 10. 東海大学大学院工学研究科, 11. 東京理科大学先進工学部機能デザイン工学科 Taiga Takahashi^1,2,3,11, Hong Zhang^4,5, Masakazu Agetsuma^6,7, Junichi Nabekura^3,6, Kohei Otomo^1,2,8, Okamura Yosuke^4,9,10, Tomomi Nemoto^1,2,3 1. Biophotonics Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 2. Division of Biophotonics, National Institute for Physiological Sciences, National Institutes of Natural Sciences,, 3. School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), 4. Micro/Nano Technology Center, Tokai University, 5. School of Chemical Engineering and Technology, Tianjin University, 6. Division of Homeostatic Development, National Institute for Physiological Sciences, National Institutes of Natural Sciences, 7. Quantum Regenerative and Biomedical Engineering Team, Institute for Quantum Life Science, 8. Department of Biochemistry and Systems Biomedicine, Graduate School of Medicine, Juntendo University, 9. Department of Applied Chemistry, School of Engineering, Tokai University, 10. Course of Applied Science, Graduate School of Engineering, Tokai University, 11. Department of Medical and Robotic Engineering Design, Faculty of Advanced Engineering, Tokyo University of Science Large-scale in vivo two-photon imaging of living animal brains is an important tool for elucidating brain function based on the coordination of multiple brain regions. To achieve two-photon imaging of living mouse brains, the open skull method has been employed for making a cranial window by replacing a portion of the mouse skull with a glass coverslip. This method can realize long-term imaging at a high resolution; however, the size of cranial windows is typically restricted to ~5 mm in diameter to avoid the pressure on the brain tissue by a flat glass coverslip. Recently, we proposed a large cranial window utilizing PEO-CYTOP nanosheet as a flexible sealing material of a cranial window for in vivo two-photon imaging [Takahashi et al. iScience, 2020]. PEO-CYTOP nanosheet is ~130 nm thickness and has a hydrophilized adhesive surface, which suppressed bleeding on the surface. More recently, we modified the PEO-CYTOP nanosheet-based method to make a large cranial window (over 9 mm in diameter) suitable for long-term imaging in awake mice. This method produced cranial windows that conformed to the curved surface of the cerebral cortex and cerebellum, suppressed inflammation and motion artifacts in an awake mouse, and maintained transparency over 5 months. Moreover, we demonstrated in vivo multi-scale imaging of neuronal structures and Ca²⁺ activity at high resolution.		7月8日（土）　13:50-15:50　Room C 3SY④-4 長期シナプス可塑的変化に必要な新規ドパミン放出機構 Long-term memory formation requires on-demand dopamine release in Drosophila 上野　耕平, 齊藤　実（公財）東京都医学総合研究所 Kohei Ueno, Minoru Saitoe Tokyo Metropolitan Institute of Medical Science Dopamine (DA) is a critical neurotransmitter for memory formation. Recent studies suggest that DA release is regulated by dopaminergic neurons (DANs) and surrounding cells. However, the mechanisms are still unclear. In Drosophila, aversive olfactory memory is formed by the association of odor and shock through DA signaling in the mushroom body (MB), which is the core of olfactory memory in insects. To examine the DA release, we stimulated odor and shock input pathways in an isolated brain. The data suggested that when odor and shock inputs coincidentally activate MB, the activated MB neurons induce local DA release from nearby DAN terminals. We named this local DA release mechanism "on-demand release" and identified that it requires CO generation by the heme oxygenase (HO) in the MB and ryanodine receptors (RyRs) in the DANs. To address whether on-demand DA release also occurs during aversive olfactory conditioning, we performed in vivo functional imaging of DA release under the confocal microscope. We found on-demand DA release on the α3 domain of the MB lobe upon coincident odor and shock presentation. The α3 domain is crucial for long-term memory (LTM). Significantly, the knockdown of either HO in the MBs or RyR in α3 projecting DANs impaired the LTM. Our long-term assay suggests that the on-demand DA release also functions in living flies and is required for LTM formation.

7月8日（土）　13:50-15:50　Room C 3SY④-5 環境光を取込む長期記憶のロバストネス Robustness of long-term memory by environmental light 坂井　貴臣東京都立大学　理学部　生命科学 Takaomi Sakai Dept. of Biological Sciences, Tokyo Metropolitan Univ., Tokyo, Japan The newly acquired memory is consolidated under specific circumstances to form stable long-term memory (LTM). Once consolidated, LTM is maintained in the cranial nervous system for an extended period. Although the mechanisms of LTM maintenance are still poorly understood, recent memory research reveals that the mechanisms of LTM maintenance differ from those of memory consolidation. In our previous study, we have identified many genes essential for LTM in Drosophila. In addition, we have found that memory is maintained for a long time in flies kept under light-dark cycles after learning, whereas it is not maintained in flies kept under constant darkness after learning. Unlike LTM maintenance, however, memory consolidation was light-independent. The LTM consolidation requires the expression of new proteins in a learning-dependent manner. In particular, the transcription factor CREB, conserved in many animal species, is known as a transcription factor regulating LTM consolidation. Interestingly, we have identified that CREB activation in the fly memory center (mushroom body, MB) is critical for LTM maintenance, and CREB transcriptional activity in the MB is also light-dependent. To elucidate the mechanism of LTM robustness, further study will need to clarify the functional differences between light-dependent and light-independent transcription by CREB.