研究者詳細 - 岡野　栄之

論文 - 岡野　栄之

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Engraftment of Human Pluripotent Stem Cell-derived Progenitors in the Inner Ear of Prenatal Mice

Takeda H., Hosoya M., Fujioka M., Saegusa C., Saeki T., Miwa T., Okano H., Minoda R.

Scientific Reports （Scientific Reports） 8 （ 1 ） 2018年12月

© 2018 The Author(s). There is, at present, no curative treatment for genetic hearing loss. We have previously reported that transuterine gene transfer of wild type CONNEXIN30 (CX30) genes into otocysts in CX30-deleted mice could restore hearing. Cell transplantation therapy might be another therapeutic option, although it is still unknown whether stem cell-derived progenitor cells could migrate into mouse otocysts. Here, we show successful cell transplantation of progenitors of outer sulcus cell-like cells derived from human-derived induced pluripotent stem cells into mouse otocysts on embryonic day 11.5. The delivered cells engrafted more frequently in the non-sensory region in the inner ear of CX30-deleted mice than in wild type mice and survived for up to 1 week after transplantation. Some of the engrafted cells expressed CX30 proteins in the non-sensory region. This is the first report that demonstrates successful engraftment of exogenous cells in prenatal developing otocysts in mice. Future studies using this mouse otocystic injection model in vivo will provide further clues for developing treatment modalities for congenital hearing loss in humans.

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Assessing cortical plasticity after spinal cord injury by using resting-state functional magnetic resonance imaging in awake adult mice

Matsubayashi K., Nagoshi N., Komaki Y., Kojima K., Shinozaki M., Tsuji O., Iwanami A., Ishihara R., Takata N., Matsumoto M., Mimura M., Okano H., Nakamura M.

Scientific Reports （Scientific Reports） 8 （ 1 ） 2018年12月

© 2018, The Author(s). Neural connectivity has recently been shown to be altered after spinal cord injury (SCI) not only in the spinal cord but also in the brain. However, to date, no studies have analyzed the functional alterations after SCI in various areas of the cerebral cortex over time. To examine the plasticity of the neural connectivity in the brain after SCI, we performed resting-state functional magnetic resonance imaging (rs-fMRI) in awake adult mice pre- and post-SCI. After a complete thoracic SCI, the functional connectivity between the primary motor (MOp) and primary sensory (SSp) areas was significantly decreased during the chronic phase. In contrast, the connectivity between the MOp and motivation area was increased. Thus, impairments in sensory and motor connections after SCI led to a time-dependent compensatory upregulation of “motor functional motivation”. Moreover, the functional connectivity between the SSp and pain-related areas, such as the caudoputamen (CP) and the anterior cingulate area (ACA), was strengthened during the chronic phase, thus suggesting that rs-fMRI can indicate the presence of neuropathic pain after SCI. Therefore, rs-fMRI is a useful tool for revealing the pathological changes that occur in the brain after SCI.

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Single-cell trajectory analysis of human homogenous neurons carrying a rare RELN variant

Arioka Y., Shishido E., Kubo H., Kushima I., Yoshimi A., Kimura H., Ishizuka K., Aleksic B., Maeda T., Ishikawa M., Kuzumaki N., Okano H., Mori D., Ozaki N.

Translational Psychiatry （Translational Psychiatry） 8 （ 1 ） 2018年12月

© 2018 The Author(s). Reelin is a protein encoded by the RELN gene that controls neuronal migration in the developing brain. Human genetic studies suggest that rare RELN variants confer susceptibility to mental disorders such as schizophrenia. However, it remains unknown what effects rare RELN variants have on human neuronal cells. To this end, the analysis of human neuronal dynamics at the single-cell level is necessary. In this study, we generated human-induced pluripotent stem cells carrying a rare RELN variant (RELN-del) using targeted genome editing; cells were further differentiated into highly homogeneous dopaminergic neurons. Our results indicated that RELN-del triggered an impaired reelin signal and decreased the expression levels of genes relevant for cell movement in human neurons. Single-cell trajectory analysis revealed that control neurons possessed directional migration even in vitro, while RELN-del neurons demonstrated a wandering type of migration. We further confirmed these phenotypes in neurons derived from a patient carrying the congenital RELN-del. To our knowledge, this is the first report of the biological significance of a rare RELN variant in human neurons based on individual neuron dynamics. Collectively, our approach should be useful for studying reelin function and evaluating mental disorder susceptibility, focusing on individual human neuronal migration.

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The pathogenesis linked to coenzyme Q10 insufficiency in iPSC-derived neurons from patients with multiple-system atrophy

Nakamoto F., Okamoto S., Mitsui J., Sone T., Ishikawa M., Yamamoto Y., Kanegae Y., Nakatake Y., Imaizumi K., Ishiura H., Tsuji S., Okano H.

Scientific Reports （Scientific Reports） 8 （ 1 ） 2018年12月

© 2018, The Author(s). Multiple-system atrophy (MSA) is a neurodegenerative disease characterized by autonomic failure with various combinations of parkinsonism, cerebellar ataxia, and pyramidal dysfunction. We previously reported that functionally impaired variants of COQ2, which encodes an essential enzyme in the biosynthetic pathway of coenzyme Q10, are associated with MSA. Here, we report functional deficiencies in mitochondrial respiration and the antioxidative system in induced pluripotent stem cell (iPSC)-derived neurons from an MSA patient with compound heterozygous COQ2 mutations. The functional deficiencies were rescued by site-specific CRISPR/Cas9-mediated gene corrections. We also report an increase in apoptosis of iPSC-derived neurons from MSA patients. Coenzyme Q10 reduced apoptosis of neurons from the MSA patient with compound heterozygous COQ2 mutations. Our results reveal that cellular dysfunctions attributable to decreased coenzyme Q10 levels are related to neuronal death in MSA, particularly in patients with COQ2 variants, and may contribute to the development of therapy using coenzyme Q10 supplementation.

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Stem cells purified from human induced pluripotent stem cell-derived neural crest-like cells promote peripheral nerve regeneration

Kimura H., Ouchi T., Shibata S., Amemiya T., Nagoshi N., Nakagawa T., Matsumoto M., Okano H., Nakamura M., Sato K.

Scientific Reports （Scientific Reports） 8 （ 1 ） 2018年12月

© 2018 The Author(s). Strategies for therapeutic cell transplantation have been assessed for use in the treatment of massive peripheral nerve defects. To support safe and efficient cell transplantation, we have focused on the purification of cells using cell surface markers. Our group previously reported low-Affinity nerve growth factor receptor (LNGFR)-and thymocyte antigen-1 (THY-1)-positive neural crest-like cells (LT-NCLCs), generated from human induced pluripotent stem cells (hiPSCs). In the present study, we investigated the efficacy of transplantation of hiPSC-derived LT-NCLCs in a murine massive peripheral nerve defect model. Animals with a sciatic nerve defect were treated with a bridging silicone tube prefilled with LT-NCLCs or medium in the transplantation (TP) and negative control (NC) groups, respectively. The grafted LT-NCLCs survived and enhanced myelination and angiogenesis, as compared to the NC group. Behavioral analysis indicated that motor functional recovery in the TP group was superior to that in the NC group, and similar to that in the autograft (Auto) group. LT-NCLCs promoted axonal regrowth and remyelination by Schwann cells. Transplantation of LT-NCLCs is a promising approach for nerve regeneration treatment of massive peripheral nerve defects.

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T-type Calcium Channels Determine the Vulnerability of Dopaminergic Neurons to Mitochondrial Stress in Familial Parkinson Disease

Tabata Y., Imaizumi Y., Sugawara M., Andoh-Noda T., Banno S., Chai M., Sone T., Yamazaki K., Ito M., Tsukahara K., Saya H., Hattori N., Kohyama J., Okano H.

Stem Cell Reports （Stem Cell Reports） 11 （ 5 ） 1171 - 1184 2018年11月

ISSN 22136711

© 2018 The Author(s) Parkinson disease (PD) is a progressive neurological disease caused by selective degeneration of dopaminergic (DA) neurons in the substantia nigra. Although most cases of PD are sporadic cases, familial PD provides a versatile research model for basic mechanistic insights into the pathogenesis of PD. In this study, we generated DA neurons from PARK2 patient-specific, isogenic PARK2 null and PARK6 patient-specific induced pluripotent stem cells and found that these neurons exhibited more apoptosis and greater susceptibility to rotenone-induced mitochondrial stress. From phenotypic screening with an FDA-approved drug library, one voltage-gated calcium channel antagonist, benidipine, was found to suppress rotenone-induced apoptosis. Furthermore, we demonstrated the dysregulation of calcium homeostasis and increased susceptibility to rotenone-induced stress in PD, which is prevented by T-type calcium channel knockdown or antagonists. These findings suggest that calcium homeostasis in DA neurons might be a useful target for developing new drugs for PD patients. Our study demonstrate the dysregulation of calcium homeostasis and increased susceptibility to rotenone-induced stress in PD patient-derived DA neurons, which are further prevented by T-type calcium channel antagonists. These findings suggest that calcium homeostasis in DA neurons would be a useful target for developing new drugs for PD patients.

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The Amelioration of Pain-Related Behavior in Mice with Chronic Spinal Cord Injury Treated with Neural Stem/Progenitor Cell Transplantation Combined with Treadmill Training

Tashiro S., Nishimura S., Shinozaki M., Takano M., Konomi T., Tsuji O., Nagoshi N., Toyama Y., Liu M., Okano H., Nakamura M.

Journal of Neurotrauma （Journal of Neurotrauma） 35 （ 21 ） 2561 - 2571 2018年11月

ISSN 08977151

© Copyright 2018, Mary Ann Liebert, Inc., publishers 2018. Progress in regenerative medicine is realizing the possibility of neural regeneration and functional recovery in spinal cord injury (SCI). Recently, rehabilitation has attracted much attention with respect to the synergistic promotion of functional recovery in combination with neural stem/progenitor cell (NS/PC) transplantation, even in the chronic refractory phase of SCI. Nevertheless, sensory disturbance is one of the most prominent sequelae, even though the effects of combination or single therapies have been investigated mostly in the context of motor recovery. To determine how combination therapy with treadmill training (TMT) and NS/PC transplantation affects the manifestation of thermal allodynia and tactile hyperalgesia in chronic phase SCI, four groups of SCI mice were used to assess pain-related behavior and histological changes: combined transplantation and TMT therapy, transplantation only, TMT only, and control groups. Thermal allodynia and coarse touch-pressure hyperalgesia exhibited significant recovery in the combined therapy group in comparison with controls, whereas there were no significant differences with fine touch-pressure hyperalgesia and motor function. Further investigation revealed fewer fibers remaining in the posterior funiculus, which contained the tracts associated with the two modalities showing less recovery; that is, touch-pressure hyperalgesia and motor function. A significant correlation was only observed between these two modalities. Although no remarkable histological recovery was found within the lesion epicenter, changes indicating amelioration of pain were observed in the lumbar enlargement of the combination therapy group. Our results suggest that amelioration of thermal allodynia and tactile hyperalgesia can be brought about by the additive effect of NS/PC transplantation and TMT. The degree of recovery seems dependent on the distribution of damage.

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The Japan Monkey Centre Primates Brain Imaging Repository for comparative neuroscience: an archive of digital records including records for endangered species

Sakai T., Hata J., Ohta H., Shintaku Y., Kimura N., Ogawa Y., Sogabe K., Mori S., Okano H., Hamada Y., Shibata S., Okano H., Oishi K.

Primates （Primates） 59 （ 6 ） 553 - 570 2018年11月

ISSN 00328332

© 2018, The Author(s). Advances in magnetic resonance imaging (MRI) and computational analysis technology have enabled comparisons among various primate brains in a three-dimensional electronic format. Results from comparative studies provide information about common features across primates and species-specific features of neuroanatomy. Investigation of various species of non-human primates is important for understanding such features, but the majority of comparative MRI studies have been based on experimental primates, such as common marmoset, macaques, and chimpanzee. A major obstacle has been the lack of a database that includes non-experimental primates’ brain MRIs. To facilitate scientific discoveries in the field of comparative neuroanatomy and brain evolution, we launched a collaborative project to develop an open-resource repository of non-human primate brain images obtained using ex vivo MRI. As an initial open resource, here we release a collection of structural MRI and diffusion tensor images obtained from 12 species: pygmy marmoset, owl monkey, white-fronted capuchin, crab-eating macaque, Japanese macaque, bonnet macaque, toque macaque, Sykes’ monkey, red-tailed monkey, Schmidt’s guenon, de Brazza’s guenon, and lar gibbon. Sixteen postmortem brain samples from the 12 species, stored in the Japan Monkey Centre (JMC), were scanned using a 9.4-T MRI scanner and made available through the JMC collaborative research program (http://www.j-monkey.jp/BIR/index_e.html). The expected significant contributions of the JMC Primates Brain Imaging Repository include (1) resources for comparative neuroscience research, (2) preservation of various primate brains, including those of endangered species, in a permanent digital form, (3) resources with higher resolution for identifying neuroanatomical features, compared to previous MRI atlases, (4) resources for optimizing methods of scanning large fixed brains, and (5) references for veterinary neuroradiology. User-initiated research projects beyond these contributions are also anticipated.

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Versatile Roles of LKB1 Kinase Signaling in Neural Development and Homeostasis

Kuwako K., Okano H.

Frontiers in Molecular Neuroscience （Frontiers in Molecular Neuroscience） 11 2018年10月

ISSN 16625099

© 2018 Kuwako and Okano. Kinase signaling pathways orchestrate a majority of cellular structures and functions across species. Liver kinase B1 (LKB1, also known as STK11 or Par-4) is a ubiquitously expressed master serine/threonine kinase that plays crucial roles in numerous cellular events, such as polarity control, proliferation, differentiation and energy homeostasis, in many types of cells by activating downstream kinases of the AMP-activated protein kinase (AMPK) subfamily members. In contrast to the accumulating evidence for LKB1 functions in nonneuronal tissues, its functions in the nervous system have been relatively less understood until recently. In the brain, LKB1 initially emerged as a principal regulator of axon/dendrite polarity in forebrain neurons. Thereafter, recent investigations have rapidly uncovered diverse and essential functions of LKB1 in the developing and mature nervous system, such as migration, neurite morphogenesis, myelination and the maintenance of neural integrity, demonstrating that LKB1 is also a multifunctional master kinase in the nervous system. In this review article, we summarize the expanding knowledge about the functional aspects of LKB1 signaling in neural development and homeostasis.

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Modeling sporadic ALS in iPSC-derived motor neurons identifies a potential therapeutic agent

Fujimori K., Ishikawa M., Otomo A., Atsuta N., Nakamura R., Akiyama T., Hadano S., Aoki M., Saya H., Sobue G., Okano H.

Nature Medicine （Nature Medicine） 24 （ 10 ） 1579 - 1589 2018年10月

ISSN 10788956

© 2018, The Author(s). Amyotrophic lateral sclerosis (ALS) is a heterogeneous motor neuron disease for which no effective treatment is available, despite decades of research into SOD1-mutant familial ALS (FALS). The majority of ALS patients have no familial history, making the modeling of sporadic ALS (SALS) essential to the development of ALS therapeutics. However, as mutations underlying ALS pathogenesis have not yet been identified, it remains difficult to establish useful models of SALS. Using induced pluripotent stem cell (iPSC) technology to generate stem and differentiated cells retaining the patients’ full genetic information, we have established a large number of in vitro cellular models of SALS. These models showed phenotypic differences in their pattern of neuronal degeneration, types of abnormal protein aggregates, cell death mechanisms, and onset and progression of these phenotypes in vitro among cases. We therefore developed a system for case clustering capable of subdividing these heterogeneous SALS models by their in vitro characteristics. We further evaluated multiple-phenotype rescue of these subclassified SALS models using agents selected from non-SOD1 FALS models, and identified ropinirole as a potential therapeutic candidate. Integration of the datasets acquired in this study permitted the visualization of molecular pathologies shared across a wide range of SALS models.

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Quantitative temporal changes in DTI values coupled with histological properties in cuprizone-induced demyelination and remyelination

Yano R., Hata J., Abe Y., Seki F., Yoshida K., Komaki Y., Okano H., Tanaka K.

Neurochemistry International （Neurochemistry International） 119 151 - 158 2018年10月

ISSN 01970186

© 2017 Elsevier Ltd Diffusion tensor imaging (DTI) is widely used to evaluate microstructural variations in brain tissue. In particular, fractional anisotropy (FA), reflecting the magnitude and orientation of anisotropic water diffusion, allows us to detect pathological events in white matter. An ex vivo DTI study coupled with histological assessment is an efficient strategy to evaluate the myelination process, i.e. demyelination and remyelination. The relationship between DTI values and myelin content or the individual cellular components such as oligodendrocytes, microglia, and astrocytes during both processes of demyelination and remyelination are not well-understood. To address this issue, we employed a cuprizone-inducible demyelination mouse model. Demyelination can be induced in this model during cuprizone exposure and termination of cuprizone exposure induces remyelination. We fed the mice cuprizone-containing chow for 4 weeks and then normal chow for an additional 4 weeks. The ex vivo DTI was performed to evaluate the white matter profiles observed by FA, mean diffusivity (MD), and radial diffusivity (RD) at both demyelinating and remyelinating time points, and then we evaluated histological properties at the same time points. The results indicated a gradual FA decrease during the cuprizone treatment (0, 2, 3, 4 weeks). A lower peak was seen at 1 week after the normal chow was resumed, with recovery to baseline at 2 and 4 weeks. MD and RD showed an opposing pattern to that of FA. These DTI values were positively or negatively correlated with myelin content regardless of the status of the white matter. The RD value was more sensitive to myelination status than FA and MD. We have clarified the temporal changes in the DTI values coupled with histological properties over both the demyelination and remyelination processes.

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Control of directionality of chromatin folding for the inter- and intra-domain contacts at the Tfap2c-Bmp7 locus

Tsujimura T., Takase O., Yoshikawa M., Sano E., Hayashi M., Takato T., Toyoda A., Okano H., Hishikawa K.

Epigenetics and Chromatin （Epigenetics and Chromatin） 11 （ 1 ） 2018年09月

© 2018 The Author(s). Background: Contact domains of chromatin serve as a fundamental unit to regulate action of enhancers for target genes. Looping between a pair of CCCTC-binding factor (CTCF)-binding sites in convergent orientations underlies the formation of contact domains, while those in divergent orientations establish domain boundaries. However, every CTCF site is not necessarily engaged in loop or boundary structures, leaving functions of CTCF in varied genomic contexts still elusive. The locus containing Tfap2c and Bmp7 encompasses two contact domains separated by a region between the two genes, termed transition zone (TZ), characterized by two arrays of CTCF sites in divergent configuration. In this study, we created deletion and inversion alleles of these and other regions across the locus and investigated how they impinge on the conformation. Results: Deletion of the whole two CTCF arrays with the CRISPR/Cas9 system resulted in impairment of blocking of chromatin contacts by the TZ, as assessed by the circular chromatin conformation capture assay (4C-seq). Deletion and inversion of either of the two arrays similarly, but less pronouncedly, led to reduction in the blocking activity. Thus, the divergent configuration provides the TZ with the strong boundary activity. Uniquely, we show the TZ harbors a 50-kb region within one of the two arrays that contacts broadly with the both flanking intervals, regardless of the presence or orientation of the other CTCF array. Further, we show the boundary CTCF array has little impact on intra-domain folding; instead, locally associating CTCF sites greatly affect it. Conclusions: Our results show that the TZ not only separates the two domains, but also bears a wide interval that shows isotropic behavior of chromatin folding, indicating a potentially complex nature of actual boundaries in the genome. We also show that CTCF-binding sites inside a domain greatly contribute to the intra-domain folding of chromatin. Thus, the study reveals diverse and context-dependent roles of CTCF in organizing chromatin conformation at different levels.

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Responses to pup vocalizations in subordinate naked mole-rats are induced by estradiol ingested through coprophagy of queen’s feces

Watarai A., Arai N., Miyawaki S., Okano H., Miura K., Mogi K., Kikusui T.

Proceedings of the National Academy of Sciences of the United States of America （Proceedings of the National Academy of Sciences of the United States of America） 115 （ 37 ） 9264 - 9269 2018年09月

ISSN 00278424

© 2018 National Academy of Sciences. All Rights Reserved. Naked mole-rats form eusocial colonies consisting of a single breeding female (the queen), several breeding males, and sexually immature adults (subordinates). Subordinates are cooperative and provide alloparental care by huddling and retrieving pups to the nest. However, the physiological mechanism(s) underlying alloparental behavior of nonbreeders remains undetermined. Here, we examined the response of subordinates to pup voice and the fecal estradiol concentrations of subordinates during the three reproductive periods of the queen, including gestation, postpartum, and nonlactating. Subordinate response to pup voice was observed only during the queen’s postpartum and was preceded by an incremental rise in subordinates’ fecal estradiol concentrations during the queen’s gestation period, which coincided with physiological changes in the queen. We hypothesized that the increased estradiol in the queen’s feces was disseminated to subordinates through coprophagy, which stimulated subordinates’ responses to pup vocalizations. To test this hypothesis, we fed subordinates either fecal pellets from pregnant queens or pellets from nonpregnant queens amended with estradiol for 9 days and examined their response to recorded pup voice. In both treatments, the subordinates exhibited a constant level of response to pup voice during the feeding period but became more responsive 4 days after the feeding period. Thus, we believe that we have identified a previously unknown system of communication in naked mole-rats, in which a hormone released by one individual controls the behavior of another individual and influences the level of responsiveness among subordinate adults to pup vocal signals, thereby contributing to the alloparental pup care by subordinates.

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The LKB1-SIK Pathway Controls Dendrite Self-Avoidance in Purkinje Cells

Kuwako K., Okano H.

Cell Reports （Cell Reports） 24 （ 11 ） 2808 - 2818.e4 2018年09月

© 2018 The Author(s) Strictly controlled dendrite patterning underlies precise neural connection. Dendrite self-avoidance is a crucial system preventing self-crossing and clumping of dendrites. Although many cell-surface molecules that regulate self-avoidance have been identified, the signaling pathway that orchestrates it remains poorly understood, particularly in mammals. Here, we demonstrate that the LKB1-SIK kinase pathway plays a pivotal role in the self-avoidance of Purkinje cell (PC) dendrites by ensuring dendritic localization of Robo2, a regulator of self-avoidance. LKB1 is activated in developing PCs, and PC-specific deletion of LKB1 severely disrupts the self-avoidance of PC dendrites without affecting gross morphology. SIK1 and SIK2, downstream kinases of LKB1, mediate LKB1-dependent dendrite self-avoidance. Furthermore, loss of LKB1 leads to significantly decreased Robo2 levels in the dendrite but not in the cell body. Finally, restoration of dendritic Robo2 level via overexpression largely rescues the self-avoidance defect in LKB1-deficient PCs. These findings reveal an LKB1-pathway-mediated developmental program that establishes dendrite self-avoidance. Kuwako and Okano show that the LKB1-SIK axis is essential for establishing dendrite self-avoidance in Purkinje cells by ensuring an appropriate level of dendritic Robo2. This study reveals a pivotal role for the LKB1 kinase pathway in the developmental program orchestrating the spatial configuration of dendrites in mammalian brain.

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LOTUS Inhibits Neuronal Apoptosis and Promotes Tract Regeneration in Contusive Spinal Cord Injury Model Mice

Ito S., Nagoshi N., Tsuji O., Shibata S., Shinozaki M., Kawabata S., Kojima K., Yasutake K., Hirokawa T., Matsumoto M., Takei K., Nakamura M., Okano H.

eNeuro （eNeuro） 5 （ 5 ） 2018年09月

Nogo receptor-1 (NgR1) signaling is involved in the limitation of axonal regeneration following spinal cord injury (SCI) through collapsing the growth cone and inhibiting neurite outgrowth. Lateral olfactory tract usher substance (LOTUS), a NgR antagonist, suppresses these pathological conditions. A previous report demonstrated the positive effects of LOTUS expression on motor function through raphespinal tract regeneration using pan-neuronally LOTUS-overexpressing transgenic mice. However, this report used a hemi-section model, which does not represent the majority of clinical SCI cases, and lacked a detailed histological analysis of other descending tracts. To determine the true therapeutic effects of LOTUS, we used a more clinically relevant contusive SCI model in female transgenic mice. Definitive tracing analyses revealed that LOTUS promoted the extensive regeneration of the reticulospinal tract across the lesion site and suppressed axonal dieback of corticospinal tract (CST). A significant increase in raphespinal tract fibers was seen from the subacute to the chronic phase after the injury, strongly suggesting that LOTUS promoted translesional elongation of this tract. Furthermore, histological analyses revealed that LOTUS had a neuroprotective effect on the injured spinal cord through suppressing cellular apoptosis during the acute phase. These neuroprotective and regenerative effects contributed to significant motor functional recovery and restoration of the motor evoked potential (MEP). Therefore, LOTUS application could prove beneficial in the treatment of SCI by promoting axonal regeneration of some descending fibers, reducing axonal dieback of CST fibers and encouraging motor function recovery.

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Optogenetic astrocyte activation evokes BOLD fMRI response with oxygen consumption without neuronal activity modulation

Takata N., Sugiura Y., Yoshida K., Koizumi M., Hiroshi N., Honda K., Yano R., Komaki Y., Matsui K., Suematsu M., Mimura M., Okano H., Tanaka K.

GLIA （GLIA） 66 （ 9 ） 2013 - 2023 2018年09月

ISSN 08941491

© 2018 Wiley Periodicals, Inc. Functional magnetic resonance imaging (fMRI) based on the blood oxygenation level-dependent (BOLD) signal has been used to infer sites of neuronal activation in the brain. A recent study demonstrated, however, unexpected BOLD signal generation without neuronal excitation, which led us to hypothesize the presence of another cellular source for BOLD signal generation. Collective assessment of optogenetic activation of astrocytes or neurons, fMRI in awake mice, electrophysiological measurements, and histochemical detection of neuronal activation, coherently suggested astrocytes as another cellular source. Unexpectedly, astrocyte-evoked BOLD signal accompanied oxygen consumption without modulation of neuronal activity. Imaging mass spectrometry of brain sections identified synthesis of acetyl-carnitine via oxidative glucose metabolism at the site of astrocyte-, but not neuron-evoked BOLD signal. Our data provide causal evidence that astrocytic activation alone is able to evoke BOLD signal response, which may lead to reconsideration of current interpretation of BOLD signal as a marker of neuronal activation.

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Calcium Transient Dynamics of Neural Ensembles in the Primary Motor Cortex of Naturally Behaving Monkeys

Kondo T., Saito R., Otaka M., Yoshino-Saito K., Yamanaka A., Yamamori T., Watakabe A., Mizukami H., Schnitzer M., Tanaka K., Ushiba J., Okano H.

Cell Reports （Cell Reports） 24 （ 8 ） 2191 - 2195.e4 2018年08月

© 2018 The Authors To understand brain circuits of cognitive behaviors under natural conditions, we developed techniques for imaging neuronal activities from large neuronal populations in the deep layer cortex of the naturally behaving common marmoset. Animals retrieved food pellets or climbed ladders as a miniature fluorescence microscope monitored hundreds of calcium indicator-expressing cortical neurons in the right primary motor cortex. This technique, which can be adapted to other brain regions, can deepen our understanding of brain circuits by facilitating longitudinal population analyses of neuronal representation associated with cognitive naturalistic behaviors and their pathophysiological processes. Kondo et al. demonstrate calcium imaging from neuronal populations using a miniature fluorescence microscope in naturally behaving non-human primates (NHPs), common marmosets. This technique marks an advance beyond methods that use fixed head positioning, which limits the study of complex, self-determined behaviors such as social interactions or fear and anxiety.

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Establishment of a human induced stem cell line (FUi002-A) from Dravet syndrome patient carrying heterozygous R1525X mutation in SCN1A gene

Tanaka Y., Higurashi N., Shirasu N., Yasunaga S., Moreira K., Okano H., Hirose S.

Stem Cell Research （Stem Cell Research） 31 11 - 15 2018年08月

ISSN 18735061

© 2018 The Authors De novo mutations in SCN1A are the most common cause of Dravet syndrome (DS), an infantile-onset epileptic encephalopathy. In this study, human induced pluripotent stem cell (hiPSC) line FUi002-A was generated from skin fibroblasts obtained from a clinically diagnosed 26-year-old male DS patient with the R1525X variant of the SCN1A gene. Skin fibroblasts were reprogrammed using OriP/EBNA-1 based episomal plasmids expressing reprogramming factors expressing OCT4, SOX2, KLF-4, L-MYC, LIN28, and p53 shRNA. The transgene-free FUi002-A showed pluripotency, three germ layer differentiation capacity in vitro, and a normal karyotype. The resulting hiPSCs were heterozygous for the mutation in the SCN1A gene.

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HER2 heterogeneity is associated with poor survival in HER2-positive breast cancer

Hosonaga M., Arima Y., Sampetrean O., Komura D., Koya I., Sasaki T., Sato E., Okano H., Kudoh J., Ishikawa S., Saya H., Ishikawa T.

International Journal of Molecular Sciences （International Journal of Molecular Sciences） 19 （ 8 ） 2018年08月

ISSN 16616596

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. Intratumoral human epidermal growth factor receptor 2 (HER2) heterogeneity has been reported in 16–36% of HER2-positive breast cancer and its clinical impact is under discussion. We examined the biological effects of HER2-heterogeneity on mouse models and analyzed metastatic brains by RNA sequence analysis. A metastatic mouse model was developed using 231-Luc (triple negative cells) and 2 HER2-positive cell lines, namely, HER2-60 and HER2-90 which showed heterogeneous and monotonous HER2 expressions, respectively. Metastatic lesions developed in 3 weeks in all the mice injected with HER2-60 cells, and in 69% of the mice injected with HER2-90 and 87.5% of the mice injected with 231-Luc. The median survival days of mice injected with 231-Luc, HER2-60, and HER2-90 cells were 29 (n = 24), 24 (n = 22) and 30 (n = 13) days, respectively. RNA sequence analysis showed that CASP-1 and its related genes were significantly downregulated in metastatic brain tumors with HER2-60 cells. The low expression of caspase-1 could be a new prognostic biomarker for early relapse in HER2-positive breast cancer.

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Recurrent Spindle Cell Carcinoma Shows Features of Mesenchymal Stem Cells

Ouchi T., Morikawa S., Shibata S., Takahashi M., Yoshikawa M., Soma T., Miyashita H., Muraoka W., Kameyama K., Kawana H., Arima Y., Saya H., Okano H., Nakagawa T., Asoda S.

Journal of Dental Research （Journal of Dental Research） 97 （ 7 ） 779 - 786 2018年07月

ISSN 00220345

© 2018, International & American Associations for Dental Research. This study investigated a case of spindle cell carcinoma (SpCC) in tongue pathological lesions. The patient experienced a local recurrence and distant metastasis after surgical intervention. Although standard chemotherapy was administered, a granulomatous mass continued to develop. This aggressive growth led to survival of the tumor. Secondary debulking surgery was performed to improve the patient’s quality of life at the request of the patient. Using a tissue sample derived from the secondary debulking surgery, we performed an analysis of the tumor’s cell surface antigens, differentiation potential, metastatic ability, and inhibition potential by anticancer reagents. In vitro analysis revealed that the cell population grown under adherent culture conditions expressed the mesenchymal stem cell (MSC) markers CD73, CD90, and CD105. The cell line established from this SpCC contained colony-forming unit fibroblasts (CFU-Fs) and exhibited multipotent differentiation into several mesenchymal lineages, including bone, cartilage, and fat. The SpCC cells also displayed vigorous mobilization. These characteristics suggested that they had the differentiation potential of mesenchymal cells, especially MSCs, rather than that of epithelial cells. The surgical specimen analyzed in this study resisted the molecular target reagent cetuximab, which is an epidermal growth factor receptor inhibitor. This clinical insight revealed that chemotherapy-resistant SpCC cells have different characteristics compared to most other cancer cells, which are sensitive to cetuximab. Our cell death assay revealed that SpCC cell death was induced by the anticancer drug imatinib, which is known to inhibit protein tyrosine kinase activity of ABL, platelet-derived growth factor receptor α (PDGFRα), and KIT. Here, we report recurrent SpCC with characteristics of MSCs and potential for treatment with imatinib.

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岡野 栄之

論文 - 岡野 栄之

岡野　栄之

論文 - 岡野　栄之