論文 - 柚崎　通介

The C-terminal juxtamembrane region of the δ2 glutamate receptors controls its export from the endoplasmic reticulum

'松田　信爾,　HANNEN ROSALIND,　松田　恵子,　山田　伸明,　TUBBS THOMAS, 柚﨑 通介'

European Journal of Neuroscience 19   1683-1690 2004年02月

研究論文（学術雑誌）, 共著, 査読有り

Specific assembly with NR3B subunit controls surface expression and calcium permeability of NMDA receptors.

'松田　恵子,　FLETCHER MATT,　紙谷　義孝,　柚﨑 通介'

Journal of Neuroscience  （ 23 ） 10064-10073 2003年

研究論文（学術雑誌）, 共著

Novel role of δ2-glutamate receptors in AMPA receptor trafficking and cerebellar learning

'平井　宏和, LAUNEY THOMAS, MIKAWA SUMIKO, TORASHIMA TAKASHI, YANAGIHARA DAI, KASAURA TSUYOSHI, MIYAMOTO AKIHIRO, 柚﨑 通介'

Nature Neuroscience  （ 6 ） 869-876 2003年

研究論文（学術雑誌）, 共著

A hot spot for hotfoot mutations in the gene encoding δ2 glutamate receptor.

'WANG YING,　松田　信爾,　DREWS VALERIE,　TORASHIMA TAKASHI,　MEISLER MIRIAM H.,　柚﨑 通介'

European Journal of Neuroscience  （ 17 ） 1581-1590 2003年

研究論文（学術雑誌）, 共著

New insights into the structure and function of glutamate receptors - The orphan receptor δ2 reveals its family’s secrets.

柚﨑 通介

The Keio Journal of Medicine  （ 52 ） 92-99 2003年

研究論文（学術雑誌）, 単著

記憶素子としてのグルタミン酸受容体

柚﨑 通介

Clinical Neuroscience  （ 21 ） 1471 2003年

研究論文（学術雑誌）, 単著

記憶はどのようにして形成されるか？−最近の話題

柚﨑 通介

慶應医学  （ 80 ） 131-139 2003年

研究論文（学術雑誌）, 単著

小脳の形成と機能における神経伝達物質受容体の役割-d2型グルタミン酸受容体を例として

柚﨑 通介

脳の科学  （ 25 ） 563-570 2003年

研究論文（学術雑誌）, 単著

Abundant extrasynaptic expression of α3β4-containing nicotinic acetylcholine receptors in the medial habenula–interpeduncular nucleus pathway in mice

Tsuzuki A., Yamasaki M., Konno K., Miyazaki T., Takei N., Tomita S., Yuzaki M., Watanabe M.

Scientific Reports 14 （ 1 ）  2024年12月

　概要を見る

Nicotinic acetylcholine receptors (nAChRs) in the medial habenula (MHb)–interpeduncular nucleus (IPN) pathway play critical roles in nicotine-related behaviors. This pathway is particularly enriched in nAChR α3 and β4 subunits, both of which are genetically linked to nicotine dependence. However, the cellular and subcellular expression of endogenous α3β4-containing nAChRs remains largely unknown because specific antibodies and appropriate detection methods were unavailable. Here, we successfully uncovered the expression of endogenous nAChRs containing α3 and β4 subunits in the MHb–IPN pathway using novel specific antibodies and a fixative glyoxal that enables simultaneous detection of synaptic and extrasynaptic molecules. Immunofluorescence and immunoelectron microscopy revealed that both subunits were predominantly localized to the extrasynaptic cell surface of somatodendritic and axonal compartments of MHb neurons but not at their synaptic junctions. Immunolabeling for α3 and β4 subunits disappeared in α5β4-knockout brains, which we used as negative controls. The enriched and diffuse extrasynaptic expression along the MHb–IPN pathway suggests that α3β4-containing nAChRs may enhance the excitability of MHb neurons and neurotransmitter release from their presynaptic terminals in the IPN. The revealed distribution pattern provides a molecular and anatomical basis for understanding the functional role of α3β4-containing nAChRs in the crucial pathway of nicotine dependence.

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Neuronal DSCAM regulates the peri-synaptic localization of GLAST in Bergmann glia for functional synapse formation

Dewa K.i., Arimura N., Kakegawa W., Itoh M., Adachi T., Miyashita S., Inoue Y.U., Hizawa K., Hori K., Honjoya N., Yagishita H., Taya S., Miyazaki T., Usui C., Tatsumoto S., Tsuzuki A., Uetake H., Sakai K., Yamakawa K., Sasaki T., Nagai J., Kawaguchi Y., Sone M., Inoue T., Go Y., Ichinohe N., Kaibuchi K., Watanabe M., Koizumi S., Yuzaki M., Hoshino M.

Nature Communications 15 （ 1 ）  2024年12月

　概要を見る

In the central nervous system, astrocytes enable appropriate synapse function through glutamate clearance from the synaptic cleft; however, it remains unclear how astrocytic glutamate transporters function at peri-synaptic contact. Here, we report that Down syndrome cell adhesion molecule (DSCAM) in Purkinje cells controls synapse formation and function in the developing cerebellum. Dscam-mutant mice show defects in CF synapse translocation as is observed in loss of function mutations in the astrocytic glutamate transporter GLAST expressed in Bergmann glia. These mice show impaired glutamate clearance and the delocalization of GLAST away from the cleft of parallel fibre (PF) synapse. GLAST complexes with the extracellular domain of DSCAM. Riluzole, as an activator of GLAST-mediated uptake, rescues the proximal impairment in CF synapse formation in Purkinje cell-selective Dscam-deficient mice. DSCAM is required for motor learning, but not gross motor coordination. In conclusion, the intercellular association of synaptic and astrocyte proteins is important for synapse formation and function in neural transmission.

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Lack of evidence for direct ligand-gated ion channel activity of GluD receptors

Itoh M., Piot L., Mony L., Paoletti P., Yuzaki M.

Proceedings of the National Academy of Sciences of the United States of America 121 （ 31 ）  2024年07月

ISSN  00278424

　概要を見る

Delta receptors (GluD1 and GluD2), members of the large ionotropic glutamate receptor (iGluR) family, play a central role in numerous neurodevelopmental and psychiatric disorders. The amino-terminal domain (ATD) of GluD orchestrates synapse formation and maturation processes through its interaction with the Cbln family of synaptic organizers and neurexin (Nrxn). The transsynaptic triad of Nrxn–Cbln–GluD also serves as a potent regulator of synaptic plasticity, at both excitatory and inhibitory synapses. Despite these recognized functions, there is still debate as to whether GluD functions as a "canonical" ion channel, similar to other iGluRs. A recent report proposes that the ATD of GluD2 imposes conformational constraints on channel activity; removal of this constraint by binding to Cbln1 and Nrxn, or removal of the ATD, reveals channel activity in GluD2 upon administration of glycine (Gly) and d-serine (d-Ser), two GluD ligands. We were able to reproduce currents when Gly or d-Ser was administered to clusters of heterologous human embryonic kidney 293 (HEK293) cells expressing Cbln1, GluD2 (or GluD1), and Nrxn. However, Gly or d-Ser, but also l-glutamate (l-Glu), evoked similar currents in naive (i.e., untransfected) HEK293 cells and in GluD2-null Purkinje neurons. Furthermore, no current was detected in isolated HEK293 cells expressing GluD2 lacking the ATD upon administration of Gly. Taken together, these results cast doubt on the previously proposed hypothesis that extracellular ligands directly gate wild-type GluD channels.

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Kainate receptors regulate synaptic integrity and plasticity by forming a complex with synaptic organizers in the cerebellum

Kakegawa W., Paternain A.V., Matsuda K., Aller M.I., Iida I., Miura E., Nozawa K., Yamasaki T., Sakimura K., Yuzaki M., Lerma J.

Cell Reports 43 （ 7 ）  2024年07月

　概要を見る

Kainate (KA)-type glutamate receptors (KARs) are implicated in various neuropsychiatric and neurological disorders through their ionotropic and metabotropic actions. However, compared to AMPA- and NMDA-type receptor functions, many aspects of KAR biology remain incompletely understood. Our study demonstrates an important role of KARs in organizing climbing fiber (CF)-Purkinje cell (PC) synapses and synaptic plasticity in the cerebellum, independently of their ion channel or metabotropic functions. The amino-terminal domain (ATD) of the GluK4 KAR subunit binds to C1ql1, provided by CFs, and associates with Bai3, an adhesion-type G protein-coupled receptor expressed in PC dendrites. Mice lacking GluK4 exhibit no KAR-mediated responses, reduced C1ql1 and Bai3 levels, and fewer CF-PC synapses, along with impaired long-term depression and oculomotor learning. Remarkably, introduction of the ATD of GluK4 significantly improves all these phenotypes. These findings demonstrate that KARs act as synaptic scaffolds, orchestrating synapses by forming a KAR-C1ql1-Bai3 complex in the cerebellum.

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The hidden face of GluD1 at inhibitory synapses

Itoh M., Yuzaki M.

Cell Research 34 （ 6 ） 405 - 406 2024年06月

ISSN  10010602

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Activity-driven synaptic translocation of LGI1 controls excitatory neurotransmission

Cuhadar U., Calzado-Reyes L., Pascual-Caro C., Aberra A.S., Ritzau-Jost A., Aggarwal A., Ibata K., Podgorski K., Yuzaki M., Geis C., Hallerman S., Hoppa M.B., de Juan-Sanz J.

Cell Reports 43 （ 5 ）  2024年05月

　概要を見る

The fine control of synaptic function requires robust trans-synaptic molecular interactions. However, it remains poorly understood how trans-synaptic bridges change to reflect the functional states of the synapse. Here, we develop optical tools to visualize in firing synapses the molecular behavior of two trans-synaptic proteins, LGI1 and ADAM23, and find that neuronal activity acutely rearranges their abundance at the synaptic cleft. Surprisingly, synaptic LGI1 is primarily not secreted, as described elsewhere, but exo- and endocytosed through its interaction with ADAM23. Activity-driven translocation of LGI1 facilitates the formation of trans-synaptic connections proportionally to the history of activity of the synapse, adjusting excitatory transmission to synaptic firing rates. Accordingly, we find that patient-derived autoantibodies against LGI1 reduce its surface fraction and cause increased glutamate release. Our findings suggest that LGI1 abundance at the synaptic cleft can be acutely remodeled and serves as a critical control point for synaptic function.

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Human-induced pluripotent stem cell-derived neural stem/progenitor cell ex vivo gene therapy with synaptic organizer CPTX for spinal cord injury

Saijo Y., Nagoshi N., Kawai M., Kitagawa T., Suematsu Y., Ozaki M., Shinozaki M., Kohyama J., Shibata S., Takeuchi K., Nakamura M., Yuzaki M., Okano H.

Stem Cell Reports 19 （ 3 ） 383 - 398 2024年03月

ISSN  22136711

　概要を見る

The transplantation of neural stem/progenitor cells (NS/PCs) derived from human induced pluripotent stem cells (hiPSCs) has shown promise in spinal cord injury (SCI) model animals. Establishing a functional synaptic connection between the transplanted and host neurons is crucial for motor function recovery. To boost therapeutic outcomes, we developed an ex vivo gene therapy aimed at promoting synapse formation by expressing the synthetic excitatory synapse organizer CPTX in hiPSC-NS/PCs. Using an immunocompromised transgenic rat model of SCI, we evaluated the effects of transplanting CPTX-expressing hiPSC-NS/PCs using histological and functional analyses. Our findings revealed a significant increase in excitatory synapse formation at the transplantation site. Retrograde monosynaptic tracing indicated extensive integration of transplanted neurons into the surrounding neuronal tracts facilitated by CPTX. Consequently, locomotion and spinal cord conduction significantly improved. Thus, ex vivo gene therapy targeting synapse formation holds promise for future clinical applications and offers potential benefits to individuals with SCI.

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Bioorthogonal chemical labeling of endogenous neurotransmitter receptors in living mouse brains

Nonaka H., Sakamoto S., Shiraiwa K., Ishikawa M., Tamura T., Okuno K., Kondo T., Kiyonaka S., Susaki E.A., Shimizu C., Ueda H.R., Kakegawa W., Arai I., Yuzaki M., Hamachi I.

Proceedings of the National Academy of Sciences of the United States of America 121 （ 6 ）  2024年

ISSN  00278424

　概要を見る

Neurotransmitter receptors are essential components of synapses for communication between neurons in the brain. Because the spatiotemporal expression profiles and dynamics of neurotransmitter receptors involved in many functions are delicately governed in the brain, in vivo research tools with high spatiotemporal resolution for receptors in intact brains are highly desirable. Covalent labeling by chemical reaction (chemical labeling) of proteins without genetic manipulation is now a powerful method for analyzing receptors in vitro. However, selective target receptor labeling in the brain has not yet been achieved. This study shows that ligand-directed alkoxyacylimidazole (LDAI) chemistry can be used to selectively tether synthetic probes to target endogenous receptors in living mouse brains. The reactive LDAI reagents with negative charges were found to diffuse well over the whole brain and could selectively label target endogenous receptors, including AMPAR, NMDAR, mGlu1, and GABAAR. This simple and robust labeling protocol was then used for various applications: three-dimensional spatial mapping of endogenous receptors in the brains of healthy and disease-model mice; multi-color receptor imaging; and pulse–chase analysis of the receptor dynamics in postnatal mouse brains. Here, results demonstrated that bioorthogonal receptor modification in living animal brains may provide innovative molecular tools that contribute to the in-depth understanding of complicated brain functions.

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Brain-Specific Angiogenesis Inhibitor 3 Is Expressed in the Cochlea and Is Necessary for Hearing Function in Mice

Saegusa C., Kakegawa W., Miura E., Aimi T., Mogi S., Harada T., Yamashita T., Yuzaki M., Fujioka M.

International Journal of Molecular Sciences 24 （ 23 ）  2023年12月

ISSN  16616596

　概要を見る

Mammalian auditory hair cells transduce sound-evoked traveling waves in the cochlea into nerve stimuli, which are essential for hearing function. Pillar cells located between the inner and outer hair cells are involved in the formation of the tunnel of Corti, which incorporates outer-hair-cell-driven fluid oscillation and basilar membrane movement, leading to the fine-tuned frequency-specific perception of sounds by the inner hair cells. However, the detailed molecular mechanism underlying the development and maintenance of pillar cells remains to be elucidated. In this study, we examined the expression and function of brain-specific angiogenesis inhibitor 3 (Bai3), an adhesion G-protein-coupled receptor, in the cochlea. We found that Bai3 was expressed in hair cells in neonatal mice and pillar cells in adult mice, and, interestingly, Bai3 knockout mice revealed the abnormal formation of pillar cells, with the elevation of the hearing threshold in a frequency-dependent manner. Furthermore, old Bai3 knockout mice showed the degeneration of hair cells and spiral ganglion neurons in the basal turn. The results suggest that Bai3 plays a crucial role in the development and/or maintenance of pillar cells, which, in turn, are necessary for normal hearing function. Our results may contribute to understanding the mechanisms of hearing loss in human patients.

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C1ql1-Bai3 signaling is necessary for climbing fiber synapse formation in mature Purkinje cells in coordination with neuronal activity

Aimi T., Matsuda K., Yuzaki M.

Molecular Brain 16 （ 1 ）  2023年12月

　概要を見る

Changes in neural activity induced by learning and novel environments have been reported to lead to the formation of new synapses in the adult brain. However, the underlying molecular mechanism is not well understood. Here, we show that Purkinje cells (PCs), which have established adult-type monosynaptic innervation by climbing fibers (CFs) after elimination of weak CFs during development, can be reinnervated by multiple CFs by increased expression of the synaptic organizer C1ql1 in CFs or Bai3, a receptor for C1ql1, in PCs. In the adult cerebellum, CFs are known to have transverse branches that run in a mediolateral direction without forming synapses with PCs. Electrophysiological, Ca2+-imaging and immunohistochemical studies showed that overexpression of C1ql1 or Bai3 caused these CF transverse branches to elongate and synapse on the distal dendrites of mature PCs. Mature PCs were also reinnervated by multiple CFs when the glutamate receptor GluD2, which is essential for the maintenance of synapses between granule cells and PCs, was deleted. Interestingly, the effect of GluD2 knockout was not observed in Bai3 knockout PCs. In addition, C1ql1 levels were significantly upregulated in CFs of GluD2 knockout mice, suggesting that endogenous, not overexpressed, C1ql1-Bai3 signaling could regulate the reinnervation of mature PCs by CFs. Furthermore, the effects of C1ql1 and Bai3 overexpression required neuronal activity in the PC and CF, respectively. C1ql1 immunoreactivity at CF-PC synapses was reduced when the neuronal activity of CFs was suppressed. These results suggest that C1ql1-Bai3 signaling may mediate CF synaptogenesis in mature PCs, potentially in concert with neuronal activity.

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Rab21 regulates caveolin-1-mediated endocytic trafficking to promote immature neurite pruning

Shikanai M., Ito S., Nishimura Y.V., Akagawa R., Fukuda M., Yuzaki M., Nabeshima Y.i., Kawauchi T.

EMBO Reports 24 （ 3 ）  2023年03月

ISSN  1469221X

　概要を見る

Transmembrane proteins are internalized by clathrin- and caveolin-dependent endocytosis. Both pathways converge on early endosomes and are thought to share the small GTPase Rab5 as common regulator. In contrast to this notion, we show here that the clathrin- and caveolin-mediated endocytic pathways are differentially regulated. Rab5 and Rab21 localize to distinct populations of early endosomes in cortical neurons and preferentially regulate clathrin- and caveolin-mediated pathways, respectively, suggesting heterogeneity in the early endosomes, rather than a converging point. Suppression of Rab21, but not Rab5, results in decreased plasma membrane localization and total protein levels of caveolin-1, which perturbs immature neurite pruning of cortical neurons, an in vivo-specific step of neuronal maturation. Taken together, our data indicate that clathrin- and caveolin-mediated endocytic pathways run in parallel in early endosomes, which show different molecular regulation and physiological function.

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Revisiting PFA-mediated tissue fixation chemistry: FixEL enables trapping of small molecules in the brain to visualize their distribution changes

Nonaka H., Mino T., Sakamoto S., Oh J.H., Watanabe Y., Ishikawa M., Tsushima A., Amaike K., Kiyonaka S., Tamura T., Radu Aricescu A., Kakegawa W., Miura E., Yuzaki M., Hamachi I.

Chem 9 （ 2 ） 523 - 540 2023年02月

ISSN  24519308

　概要を見る

Various small molecules have been used as functional probes for tissue imaging in medical diagnosis and pharmaceutical drugs for disease treatment. The spatial distribution, target selectivity, and diffusion/excretion kinetics of small molecules in structurally complicated specimens are critical for function. However, robust methods for precisely evaluating these parameters in the brain have been limited. Herein, we report a new method termed “fixation-driven chemical cross-linking of exogenous ligands (FixEL),” which traps and images exogenously administered molecules of interest (MOIs) in complex tissues. This method relies on protein-MOI interactions and chemical cross-linking of amine-tethered MOI with paraformaldehyde used for perfusion fixation. FixEL is used to obtain images of the distribution of the small molecules, which addresses selective/nonselective binding to proteins, time-dependent localization changes, and diffusion/retention kinetics of MOIs such as the scaffold of PET tracer derivatives or drug-like small molecules.

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