シンポジウム（Symposium）

Symposium Singularity Brain Science – toward discovery of singularity in brain system by massive trans-scale imaging – シンポジウムシンギュラリティ脳科学　ー　大規模トランススケールイメージングを用いた脳システムにおける臨界点の探索へ　ー

7月26日（金）8:30～8:53　第4会場（朱鷺メッセ　3F　301） 2S04m-1 「シンギュラリティ生物学」とは何か？ Takeharu Nagai（永井健治）阪大産研 There exist critical moments, such as the "Big Bang" where "something out of nothing gets created" or in the future, when artificial intelligence might become greater than human intelligence. These points are called singularities. In the field of biological science, discontinuous critical phenomena are broadly seen, for example, the emergence of life from the primordial soup, or the evolution and outbreak of diseases. It has been indicated that only a small number of core elements (in the case of cell, we call it "singularity cell") are required to bring about discontinuous changes to an entire multi-component system. However, the mechanism-of-action that generates such singularity-involving phenomena is not yet certain. To look deeply into singularity cells, an imaging platform that will achieve both wide field-of-view high-resolution imaging and high-speed long-term imaging, and corresponding information analysis methods. This will enable us to be at the cutting edge of new scientific fields, where researchers could uncover the underlying mechanisms for the generation of singularity cells as well as their biological functions. In order to study the processes that singularity cells, considered as minority entities, bring criticality to an entire system (ex: an organ or whole body), it is necessary to measure, analyze, and examine such biological systems in a holistic spatial-temporal manner. In order to achieve this, an imaging technology enabling to capture macroscopic spatiotemporal dynamics with microscopic precision: not only the composite trees but also the whole forest. In addition, we will develop and integrate techniques to measure and control singularity cells from the stand point of optics and molecular engineering, construct a theoretical framework to identify singularity cells and to verify the causality based on information science, and unravel the biological significance of singularity cells by verifying causality which is elicited from individual biological models. By conducting this kind of circulative researches, we will create the research field "singularity biology", with reference to its universality.		7月26日（金）8:53～9:16　第4会場（朱鷺メッセ　3F　301） 2S04m-2 シンギュラリティ生物学による神経変性疾患へのアプローチ Hiroko Bannai（坂内博子）^1,2，Michio Hiroshima（廣島通夫）³，Akihiko Takashima（高島明彦）⁴ ¹慶應大医生理 ²JST ERATO ³理研 BDR ⁴学習院大理 Deposition of the Amyloid plaque composed of Amyloidβ (Aβ) proteins, Aggregated of Tau called " neurofiblliary tangle (NFT) " are two major pathology in AD brain, preceding brain atrophy and cognitive impairment. Recent studies point out that oligomers of Amyloid beta and Tau are more toxic than amyloid plaque and NFT. Other factors such as immune system, microbes, and virus have also been shown to contribute to the development of neuropathology and AD. Researchers have succeeded in building up several well-supported theories and convincing hypothesis today. However, it still remains impossible by any of current theories to fully explain the AD pathogenesis and progression that causes the massive neuronal death: there are still " missing links" within a complicated chain of events that lead to AD. Causal relationship between Aβ/Tau oligomer formation and cell toxicity is proven, but the molecular mechanism how these oligomers cause cell death, and is not fully understood. Aggregated Tau deposition begins starts in a few cells of the locus coeruleus (LC) in the brain stem, and progressively propagate into other brain regions as the AD progresses, and finally results in massive neuronal death in the cerebral cortex. This pathological Tau accumulation process is considered to be a singularity phenomenon that we propose, as it starts from small number of cells to bring about huge changes in the brain system. To answer the fundamental question that "When, where, and how oligomers spread to the entire brain? ", we propose to develop novel methodology for seamless understanding of Tau Pathology of AD. In this talk, we will present our strategy to develop long-term imaging technology to track the propagation of toxic Tau. We will also introduce single-molecule imaging approach that will contribute to understand the molecular mechanism of Tau pathology propagation.

7月26日（金）9:16～9:39　第4会場（朱鷺メッセ　3F　301） 2S04m-3 脳内のシンギュラリティ検出のための全脳高解像度イメージング Kaoru Seiriki（勢力薫）^1,2，Atsushi Kasai（笠井淳司）¹，Takanobu Nakazawa（中澤敬信）^1,3，Hitoshi Hashimoto（橋本均）^1,4,5,6 ¹大阪大院薬 ²大阪大国際共創大学院学位プログラム推進機構 ³大阪大歯 ⁴大阪大院連合小児発達子どものこころ ⁵大阪大データビリティフロンティア機構バイオサイエンス部門 ⁶大阪大先導的学際研究機構超次元ライフイメージング研究部門 Brain functions are regulated by highly interconnected individual neurons distributed throughout the whole brain. Therefore, whole-brain imaging and systems analyses of entire brains at subcellular resolution are prerequisites for the precise understanding of the mechanisms underlying brain function and dysfunction. However, it is still challenging due to the trade-offs between imaging speed and spatial resolution. To overcome this issue and to increase the imaging throughput, we have previously developed a high-speed and scalable whole-brain imaging system, FAST (block-FAce Serial microscopy Tomography) using spinning disk confocal microscopy. Currently, we have been applying FAST to unbiased and hypothesis-free approaches to identify cellular level alterations associated with behavioral regulation. Combination of genetic labeling approaches and FAST imaging allows mapping neuronal projection, neuronal activation and cell-type-specific distribution at single cell level throughout the whole brain. Using these approaches, we successfully identified the neurons that are activated in an experience-dependent manner, and currently, we are examining the functional roles of a subset of those neurons. The obtained whole-brain images can be quantified based on the number and morphology of the cells and converted into numerical data including spatial coordinates of cells, and subsequently these data are applicable to multivariate and machine learning analyses. Thus, the FAST whole-brain imaging will provide new opportunities for finding a singularity in the brain.		7月26日（金）9:39～10:02　第4会場（朱鷺メッセ　3F　301） 2S04m-4 シンギュラリティ脳科学のための挑戦的イメージング技術 Tomonobu Watanabe（渡邉朋信）理研BDR 先端バイオイメージング研究チーム People explore a rare event of single elements causing state transition of its assemblage in singularity biology. We has developed measurement technologies to help for ""singularity"" people based on optical microscopy. In this symposium, we'd like to introduce two different kinds of the technologies regarding neuroscience. The first one is a new structural analysis of second harmonic generation (SHG). SHG microscopy has been used to visualize fiber structures in living specimens including microtubules as a label-free modality. Since SHG arises from the electrical polarity in the material and the electrical polarity of the protein depends on its structure, the SHG signal contains structural information in the protein. Hence, the SHG microscopy can be a new tool of protein structural analysis of microtubules. Here we demonstrated that the polarization characteristics of SHG differ depending on the microtubule structure by actual measurement, and established a method to estimate effective angle (φ) of αβ tubulin dimer from the SHG polarization. Interestingly, when kinesin binds to microtubules, the value of φ exhibited sigmoid response to the concentration of the added kinesin, indicating that the kinesin biding allostarically induced the re-orientation of the dipole of αβ tubulin dimer in microtubules. Now, we are achieving to evaluate the nucleotide-dependent structure in a single microtubule fiber. The second one is a new microscope to observe deep sites in a brain. Observation depth of optical microscopes has been limited to several hundreds of μm due to low permeability of light in living samples. To overcome this fundamental problem, near infrared light (650-900 nm) has been used so far. However the signal to noise (S/N) ratio is often still inadequate for biology researchers. We are applying the second optical window region (2nd-NIR, 1000-1300 nm) for the deep-tissue imaging. The most advantage of use of the 2nd-NIR region is that there is almost no autofluorescence source in this region. This region has not been used for long time because of no useful dyes and cameras. We newly developed bioapplicable 2nd-NIR quantum dots and the InGaAs CCD camera specialized for bioimaging. The S/N ratio was improved 60-folds than the current NIR observation, and the optical depth achieved 4 mm. We expect that the 2nd-NIR microscopy is being an essential tool in neuroscience.

7月26日（金）10:22～10:25　第4会場（朱鷺メッセ　3F　301） 2S04m-5 Near-infrared upconversion optogenetics and nanoscopy Shuo Chen（Chen Shuo）^1,2，Xiaogang Liu（Liu Xiaogang）³，Thomas J McHugh（McHugh Thomas J）² ¹Hellen Wills Neuroscience Institute, University of California, Berkeley ²Lab. for Circuit and Behavioral Physiol., RIKEN CBS ³Department of Chemistry, National University of Singapore, Singapore Optogenetics, driven by the development of light-gated rhodopsins, has revolutionized the experimental interrogation of neural circuits and holds promise for next-generation treatment of neurological disorders. However, it is limited by the inability of visible light to penetrate deep inside brain tissue. Red-shifted variants of rhodopsins have been developed, but their action spectra still fall out of the near-infrared (NIR) optical window (650-1350 nm) where light has its maximal depth of penetration in brain tissue. We developed a novel nanotechnology-based approach for NIR optogenetics, where lanthanide-doped upconversion nanocrystals (UCNPs) were used to absorb tissue-penetrating 980 nm NIR and emit visible light for rhodopsin activation. Due to lanthanides' ladder-like electronic energy structure, the emission of UCNPs can be precisely tuned to a particular wavelength by control of energy transfer via selective lanthanide-ion doping. For instance, incorporation of Tm3+ into Yb3+ doped host lattices leads to blue emission (~470 nm) that matches the maximum absorption of channelrhodopsin-2 for neuronal activation, while the Yb3+/Er3+ couple emits green light (~540 nm) compatible with activation of halorhodopsin or archaerhodopsin for neuronal inhibition. We demonstrated that molecularly tailored UCNPs could serve as optogenetic actuators of transcranial NIR to functionally stimulate deep brain neurons in mice. Transcranial NIR UCNP-mediated optogenetics evoked dopamine release from genetically tagged neurons in the ventral tegmental area, induced brain oscillations via activation of inhibitory neurons in the medial septum, silenced seizure via inhibition of excitatory cells in the hippocampus, and triggered memory recall via excitation of a hippocampal engram. We further found that the UCNPs can be retrogradely transported along axons by dynein motor protiens. Taking advantage of UCNPs as nanoscopic probes, we achived quantitative in situ tracking of motor proteins in different depth planes with single-particle resolution. UCNP technology would open the door to less-invasive optical neuronal imaging and manipulation with the potential for remote therapy.