記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

DOI： 10.1111/jnc.15217

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その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/jnc.15217

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.neuroscience.2020.06.004

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1084/jem.20171285

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Medical Association of Nippon Medical School  

Background: Photoreceptors differentiated from somatic cells are a useful tool for transplantation and drug screening. We previously showed that photosensitive cells are differentiated from human fibroblasts by direct reprogramming. In induced pluripotent stem (iPS) cells or embryonic stem (ES) cells, the properties of differentiated cells differ among the source of cell lines. However, whether or not the properties of the photosensitive cells produced by direct reprogramming are controlled by the origin of the cell line remains unknown. Methods: We compared the morphological and physiological properties of photosensitive cells induced by two fibroblast cell lines. Results: The differentiated cells had larger somas and more primary processes than the non-infected cells in both cell lines. The degree of morphological change was statistically different between the two cell lines. In addition, physiological responses to light differed between the two cell lines. An outward current (photoreceptor-like response) was observed in both cell lines, while an inward current (intrinsically photosensitive retinal ganglion cell-like response) was observed only in one cell line under light stimulation. Conclusions: These results suggest that photosensitive cells produced from different cell lines by direct reprogramming might express different phenotypes.

DOI： 10.1272/jnms.2018_85-17

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Society for Neuroscience  

Hilar mossy cells (HMCs) in the hippocampus receive glutamatergic input from dentate granule cells (DGCs) via mossy fibers (MFs) and back-projections from CA3 pyramidal neuron collateral axons. Many fundamental features of these excitatory synapses have not been characterized in detail despite their potential relevance to hippocampal cognitive processing and epilepsy-induced adaptations in circuit excitability. In this study, we compared preand postsynaptic parameters between MF and CA3 inputs to HMCs in young and adult mice of either sex and determined the relative contributions of the respective excitatory inputs during in vitro and in vivo models of hippocampal hyperexcitability. The two types of excitatory synapses both exhibited a modest degree of short-term plasticity, with MF inputs to HMCs exhibiting lower paired-pulse (PP) and frequency facilitation than was described previously for MF–CA3 pyramidal cell synapses. MF–HMC synapses exhibited unitary excitatory synaptic currents (EPSCs) of larger amplitude, contained postsynaptic kainate receptors, and had a lower NMDA/AMPA receptor ratio compared to CA3–HMC synapses. Pharmacological induction of hippocampal hyperexcitability in vitro transformed the abundant but relatively weak CA3–HMC connections to very large amplitude spontaneous bursts of compound EPSCs (cEPSCs) in young mice (∽P20) and, to a lesser degree, in adult mice (∽P70). CA3–HMC cEPSCs were also observed in slices prepared from mice with spontaneous seizures several weeks after intrahippocampal kainate injection. Strong excitation of HMCs during synchronous CA3 activity represents an avenue of significant excitatory network generation back to DGCs and might be important in generating epileptic networks.

DOI： 10.1523/ENEURO.0364-17.2017

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER PHYSIOLOGICAL SOC  

Choline uptake into the presynaptic terminal of cholinergic neurons is mediated by the high-affinity choline transporter and is essential for acetylcholine synthesis. In a previous study, we reported that P2X(2) purinoceptors are selectively expressed in OFF-cholinergic amacrine cells of the mouse retina. Under specific conditions, P2X(2) purinoceptors acquire permeability to large cations, such as N-methyl-D-glucamine, and therefore potentially could act as a noncanonical pathway for choline entry into neurons. We tested this hypothesis in OFF-cholinergic amacrine cells of the mouse retina. ATP-induced choline currents were observed in OFF-cholinergic amacrine cells, but not in ON-cholinergic amacrine cells, in mouse retinal slice preparations. High-affinity choline transporters are expressed at higher levels in ON-cholinergic amacrine cells than in OFF-cholinergic amacrine cells. In dissociated preparations of cholinergic amacrine cells, ATP-activated cation currents arose from permeation of extracellular choline. We also examined the pharmacological properties of choline currents. Pharmacologically, alpha,beta-methylene ATP did not produce a cation current, whereas ATP gamma S and benzoyl-benzoyl-ATP (BzATP) activated choline currents. However, the amplitude of the choline current activated by BzATP was very small. The choline current activated by ATP was strongly inhibited by pyridoxalphosphate-6-azophenyl- 2', 4'-sulfonic acid. Accordingly, P2X(2) purinoceptors expressed in HEK-293T cells were permeable to choline and similarly functioned as a choline uptake pathway. Our physiological and pharmacological findings support the hypothesis that P2 purinoceptors, including P2X(2) purinoceptors, function as a novel choline transport pathway and may provide a new regulatory mechanism for cholinergic signaling transmission at synapses in OFF-cholinergic amacrine cells of the mouse retina.
NEW & NOTEWORTHY Choline transport across the membrane is exerted by both the high-affinity and low-affinity choline transporters. We found that choline can permeate P2 purinergic receptors, including P2X(2) purinoceptors, in cholinergic neurons of the retina. Our findings show the presence of a novel choline transport pathway in cholinergic neurons. Our findings also indicate that the permeability of P2X(2) purinergic receptors to choline observed in the heterologous expression system may have a physiological relevance in vivo.

DOI： 10.1152/jn.00506.2016

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER IRELAND LTD  

ATP activates P2X receptors and acts as a neurotransmitter in the nervous system. We have previously reported that P2X receptors modulate the firing rate of retinal ganglion cells. Since many subtypes of P2X receptors are distributed in the mouse retina, it is likely that the modulatory effects of P2X receptor mediated signaling can occur at multiple synaptic levels in the retina. In this study, we investigated whether P2X receptors expressed between the photoreceptor layer and the inner nuclear layer in the mouse retina were physiologically functional, by electroretinography (ERG). In the combined rod-cone ERG and the scotopic ERG, intravitreal injection of PPADS, an antagonist of P2X receptors, had no effects on the amplitude of the a-wave, but decreased the amplitude of the b-wave. In the photopic ERG, intravitreal injection of PPADS significantly decreased the amplitude of both the a-wave and the b-wave. In ex vivo recordings, a decrease in the b-wave amplitude was observed at 20 mu M PPADS, confirming that the inhibition of the b-wave by intravitreal injection of PPADS is due to the inhibition of P2X receptors. Our findings suggest that P2X receptor-mediated signaling has a physiological effect in both the rod and the cone pathways in postreceptoral processing. (c) 2016 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

DOI： 10.1016/j.neures.2016.09.012

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：COMPANY OF BIOLOGISTS LTD  

Direct reprogramming is a promising, simple and low-cost approach to generate target cells from somatic cells without using induced pluripotent stem cells. Recently, peripheral blood mononuclear cells (PBMCs) have attracted considerable attention as a somatic cell source for reprogramming. As a cell source, PBMCs have an advantage over dermal fibroblasts with respect to the ease of collecting tissues. Based on our studies involving generation of photosensitive photoreceptor cells from human iris cells and human dermal fibroblasts by transduction of photoreceptor-related transcription factors via retrovirus vectors, we transduced these transcription factors into PBMCs via Sendai virus vectors. We found that retinal disease-related genes were efficiently detected in CRX-transduced cells, most of which are crucial to photoreceptor functions. In functional studies, a light-induced inward current was detected in some CRX-transduced cells. Moreover, by modification of the culture conditions including additional transduction of RAX1 and NEUROD1, we found a greater variety of retinal disease-related genes than that observed in CRX-transduced PBMCs. These data suggest that CRX acts as a master control gene for reprogramming PBMCs into photoreceptor-like cells and that our induced photoreceptor-like cells might contribute to individualized drug screening and disease modeling of inherited retinal degeneration.

DOI： 10.1242/bio.016477

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記述言語：日本語   出版者・発行元：(NPO)日本肺癌学会  

ISSN : 0386-9628, eISSN : 1348-9992, 医中誌Web ID : 2016155365

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PUBLIC LIBRARY SCIENCE  

Molecular target therapy for cancer is characterized by unique adverse effects that are not usually observed with cytotoxic chemotherapy. For example, the anaplastic lymphoma kinase (ALK)-tyrosine kinase inhibitor crizotinib causes characteristic visual disturbances, whereas such effects are rare when another ALK-tyrosine kinase inhibitor, alectinib, is used. To elucidate the mechanism responsible for these visual disturbances, the responses to light exhibited by retinal ganglion cells treated with these agents were evaluated using a C57BL6 mouse ex vivo model. Both crizotinib and alectinib changed the firing rate of ON and OFF type retinal ganglion cells. However, the ratio of alectinib-affected cells (15.7%) was significantly lower than that of crizotinib-affected cells (38.6%). Furthermore, these drugs changed the response properties to light stimuli of retinal ganglion cells in some of the affected cells, i.e., OFF cells responded to both ON and OFF stimuli, etc. Finally, the expressions of ALK (a target receptor of both crizotinib and alectinib) and of MET and ROS1 (additional target receptors of crizotinib) were observed at the mRNA level in the retina. Our findings suggest that these drugs might target retinal ganglion cells and that the potency of the drug actions on the light responses of retinal ganglion cells might be responsible for the difference in the frequencies of visual disturbances observed between patients treated with crizotinib and those treated with alectinib. The present experimental system might be useful for screening new molecular target agents prior to their use in clinical trials.

DOI： 10.1371/journal.pone.0135521

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

Direction selectivity in the retina has been studied as a model of dendritic computation of neural circuits. Starburst amacrine cells (SACs) have been examined as a model system of dendritic computation as they play a pivotal role in the formation of direction selectivity. Because the difference of anatomical location inside the retina made ON-SACs an easier target to record, the biophysical properties of ON-SACs have been used to predict those of OFF-SACs. In this study, we systematically compared the responses of ON-and OFF-SACs to the two principal neurotransmitters, glycine and glutamate. We found that responses to glycine were significantly larger in ON-SACs than in OFF-SACs. In contrast, ON-and OFF-SACs responded similarly to glutamate. The amplitude of glycine responses in ON-SACs increased after eye opening and the largest amplitude was observed at postnatal day 28. On the other hand, no increase in the amplitude of glycine responses in OFF-SACs was observed until postnatal day 28. Glycine-evoked currents were inhibited by the application of strychnine. Glutamate-evoked currents were mimicked by the application of AMPA or kainite, and responses to N-methyl-D-aspartate were observed in the absence of Mg2+ block. Glutamate-evoked currents produced an increase in the frequency of GABAergic inhibitory postsynaptic currents. Our results suggest that signal processing in ON-SACs cannot be directly used to understand the properties of OFF-SACs. Therefore fully defining the physiological properties of OFF-SACs will be critical to understanding and modelling direction selectivity in the retina.

DOI： 10.1113/jphysiol.2014.271148

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY  

Redirecting differentiation of somatic cells by over-expression of transcription factors is a promising approach for regenerative medicine, elucidation of pathogenesis and development of new therapies. We have previously defined a transcription factor combination, that is, CRX, RAX and NEUROD, that can generate photosensitive photoreceptor cells from human iris cells. Here, we show that human dermal fibroblasts are differentiated to photoreceptor cells by the same transcription factor combination as human iris cells. Transduction of a combination of the CRX, RAX and NEUROD genes up-regulated expression of the photoreceptor-specific genes, recoverin, blue opsin and PDE6C, in all three strains of human dermal fibroblasts that were tested. Additional OTX2 gene transduction increased up-regulation of the photoreceptor-specific genes blue opsin, recoverin, S-antigen, CNGB3 and PDE6C. Global gene expression data by microarray analysis further showed that photoreceptor-related functional genes were significantly increased in induced photoreceptor cells. Functional analysis, that is, patch-clamp recordings, clearly revealed that induced photoreceptor cells from fibroblasts responded to light. Both the NRL gene and the NR2E3 gene were endogenously up-regulated in induced photoreceptor cells, implying that exogenous CRX, RAX, OTX2 and NEUROD, but not NRL, are sufficient to generate rod photoreceptor cells.

DOI： 10.1111/gtc.12127

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担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：The Medical Association of Nippon Medical School  

DOI： 10.1272/manms.10.4

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その他リンク： http://search.jamas.or.jp/link/ui/2014159020

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER  

There is increasing evidence that ATP acts on purinergic receptors and mediates synaptic transmission in the retina. In a previous study, we raised the possibility that P2X-purinoceptors, presumably P2X(2)-purinoceptors in OFF-cholinergic amacrine cells, play a key role in the formation of OFF pathway-specific modulation. In this study, we examined whether the P2Y(1)-purinoceptors can function in cholinergic amacrine cells in the mouse retina since cholinergic amacrine cells in the rat retina express P2Y(1)-purinoceptors. P2Y(1)-purinoceptors were shown to be expressed in dendrites of both ON- and OFF-cholinergic amacrine cells in adults. At postnatal day 7, there was immunoreactivity for P2Y(1)-purinoceptors in the soma of cholinergic amacrine cells. At postnatal day 14, weak immunoreactivity for P2Y(1)-purinoceptors was detected in the dendrites but not in the soma of cholinergic amacrine cells. At postnatal day 21, strong immunoreactivity for P2Y(1)-purinoceptors was detected in dendrites of cholinergic amacrine cells. The expression pattern of P2Y(1)-purinoceptors was not affected by visual experience. We concluded that P2Y(1)-purinoceptors are not involved in the OFF-pathway-specific signal transmission in cholinergic amacrine cells of the mouse retina.

DOI： 10.1007/s10735-013-9525-4

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SOC NEUROSCIENCE  

"How is information decoded in the brain?" is one of the most difficult and important questions in neuroscience. We have developed a general framework for investigating to what extent the decoding process in the brain can be simplified. First, we hierarchically constructed simplified probabilistic models of neural responses that ignore more than Kth-order correlations using the maximum entropy principle. We then computed how much information is lost when information is decoded using these simplified probabilistic models (i.e., "mismatched decoders"). To evaluate the information obtained by mismatched decoders, we introduced an information theoretic quantity, I-star, which was derived by extending the mutual information in terms of communication rate across a channel. We showed that I-star provides consistent results with the minimum mean-square error as well as the mutual information, and demonstrated that a previously proposed measure quantifying the importance of correlations in decoding substantially deviates from I-star when many cells are analyzed. We then applied this proposed framework to spike data for vertebrate retina using short natural scene movies of 100 ms duration as a set of stimuli and computing the information contained in neural activities. Although significant correlations were observed in population activities of ganglion cells, information loss was negligibly small even if all orders of correlation were ignored in decoding. We also found that, if we inappropriately assumed stationarity for long durations in the information analysis of dynamically changing stimuli, such as natural scene movies, correlations appear to carry a large proportion of total information regardless of their actual importance.

DOI： 10.1523/JNEUROSCI.4360-09.2010

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PUBLIC LIBRARY SCIENCE  

The reasons for using natural stimuli to study sensory function are quickly mounting, as recent studies have revealed important differences in neural responses to natural and artificial stimuli. However, natural stimuli typically contain strong correlations and are spherically asymmetric (i.e. stimulus intensities are not symmetrically distributed around the mean), and these statistical complexities can bias receptive field (RF) estimates when standard techniques such as spike-triggered averaging or reverse correlation are used. While a number of approaches have been developed to explicitly correct the bias due to stimulus correlations, there is no complementary technique to correct the bias due to stimulus asymmetries. Here, we develop a method for RF estimation that corrects reverse correlation RF estimates for the spherical asymmetries present in natural stimuli. Using simulated neural responses, we demonstrate how stimulus asymmetries can bias reverse-correlation RF estimates (even for uncorrelated stimuli) and illustrate how this bias can be removed by explicit correction. We demonstrate the utility of the asymmetry correction method under experimental conditions by estimating RFs from the responses of retinal ganglion cells to natural stimuli and using these RFs to predict responses to novel stimuli.

DOI： 10.1371/journal.pone.0003060

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

Adenosine trisphosphate (ATP) activates purinoceptors and acts as a neurotransmitter in the nervous system. In the retina, we previously reported that the immunohistochemical distribution of the subset of P2-purinoceptors differs between the ON and OFF pathways. Here, we investigated whether ATP activates P2-purinoceptors and modulates the physiological function of the mouse retina. We also examined if signal processing by P2-purinoceptors is pathway specific. Results showed that ATP activated both ON- and OFF-cholinergic amacrine cells. However, responses in OFF-cholinergic amacrine cells were greater than those in ON-cholinergic amacrine cells. Pharmacological studies in OFF-cholinergic amacrine cells showed that the response of OFF-cholinergic amacrine cells is mediated P2X(2)-purinoceptors. Further, ATP increased gamma-aminobutyric acid (GABA)ergic inhibitory postsynaptic currents (IPSCs) in OFF- but not ON-cholinergic amacrine cells. The increase in GABAergic IPSCs was mediated by P2-purinoceptors. P2-purinoceptor-mediated signals suppressed OFF ganglion cells but activated ON ganglion cells. Our findings indicate that ATP physiologically modulates signal processing of the ON and OFF pathways in a pathway-specific manner through P2-purinoceptors.

DOI： 10.1111/j.1460-9568.2008.06317.x

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出版者・発行元：Curran Associates, Inc.  

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その他リンク： http://dblp.uni-trier.de/db/conf/nips/nips2008.html#conf/nips/OizumiIIHO08

担当区分：筆頭著者   記述言語：日本語  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

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担当区分：筆頭著者   記述言語：英語  

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担当区分：筆頭著者   記述言語：英語  

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担当区分：筆頭著者   記述言語：英語  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

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記述言語：英語   会議種別：ポスター発表  

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記述言語：英語   会議種別：シンポジウム・ワークショップ パネル（公募）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：英語   会議種別：シンポジウム・ワークショップ パネル（指名）  

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記述言語：英語   会議種別：シンポジウム・ワークショップ パネル（公募）  

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会議種別：口頭発表（招待・特別）  

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記述言語：英語   会議種別：ポスター発表  

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記述言語：英語   会議種別：シンポジウム・ワークショップ パネル（公募）  

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記述言語：英語   会議種別：ポスター発表  

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記述言語：英語   会議種別：ポスター発表  

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記述言語：英語   会議種別：ポスター発表  

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