論文 - 田中　謙二

Microfluctuations in Capillary Lumens Independent of Pericyte Lining Density in the Anesthetized Mouse Cortex

Suzuki H., Murata J., Unekawa M., Kanno I., Izawa Y., Tomita Y., Tanaka K.F., Nakahara J., Masamoto K.

Microcirculation 31 （ 8 ） e12885 2024年11月

ISSN  10739688

　概要を見る

Objective: This study aimed to examine the spatiotemporal coherence of capillary lumen fluctuations in relation to spatial variations in the pericyte lining in the cortex of anesthetized mice. Methods: Two-photon microscopic angiography data (previously published) were reanalyzed, and spatial variations in capillary diameter fluctuations at rest and in capillary lining with vascular mural cells were measured along capillary centerlines. Results: Relatively large diameters of the capillaries (5.5 μm) coincided with a dense pericyte lining, while small capillaries (4.3 μm) had a sparse pericyte lining. Temporal variations had a frequency of about 0.1 Hz with an amplitude of 0.5 μm, which were negatively correlated with pericyte lining density. Spatial frequency analysis further revealed a common pattern of spatial variations in capillary diameter and pericyte lining, but temporal variations differed. The temporal variations in capillary lumens were locally distinct from those in neighboring locations, suggesting intrinsic fluctuations independent of the pericyte lining. Conclusions: Capillary lumens in the brain exhibit slow microfluctuations that are independent of pericyte lining. These microfluctuations could affect the distribution of flowing blood cells and may be important for homogenizing their distribution in capillary networks.

• Access to Document (DOI)

Temporal and Potential Predictive Relationships between Sleep Spindle Density and Spike-and-Wave Discharges

Abdelaal M.S., Kato T., Natsubori A., Tanaka K.F.

Eneuro 11 （ 9 ）  2024年09月

　概要を見る

Spike-and-wave discharges (SWDs) and sleep spindles are characteristic electroencephalographic (EEG) hallmarks of absence seizures and nonrapid eye movement sleep, respectively. They are commonly generated by the cortico–thalamo–cortical network including the thalamic reticular nucleus (TRN). It has been reported that SWD development is accompanied by a decrease in sleep spindle density in absence seizure patients and animal models. However, whether the decrease in sleep spindle density precedes, coincides with, or follows, the SWD development remains unknown. To clarify this, we exploited Pvalb-tetracycline transactivator (tTA)::tetO-ArchT (PV-ArchT) double-transgenic mouse, which can induce an absence seizure phenotype in a time-controllable manner by expressing ArchT in PV neurons of the TRN. In these mice, EEG recordings demonstrated that a decrease in sleep spindle density occurred 1 week before the onset of typical SWDs, with the expression of ArchT. To confirm such temporal relationship observed in these genetic model mice, we used a gamma-butyrolactone (GBL) pharmacological model of SWDs. Prior to GBL administration, we administered caffeine to wild-type mice for 3 consecutive days to induce a decrease in sleep spindle density. We then administered low-dose GBL, which cannot induce SWDs in normally conditioned mice but led to the occurrence of SWDs in caffeine-conditioned mice. These findings indicate a temporal relationship in which the decrease in sleep spindle density consistently precedes SWD development. Furthermore, the decrease in sleep spindle activity may have a role in facilitating the development of SWDs. Our findings suggest that sleep spindle reductions could serve as early indicators of seizure susceptibility.

• Access to Document (DOI)

A rapidly progressive multiple system atrophy-cerebellar variant model presenting marked glial reactions with inflammation and spreading of α-synuclein oligomers and phosphorylated α-synuclein aggregates.

Yamaguchi H, Nishimura Y, Matsuse D, Sekiya H, Masaki K, Tanaka T, Saiga T, Harada M, Kira YI, Dickson DW, Fujishima K, Matsuo E, Tanaka KF, Yamasaki R, Isobe N, Kira JI

Brain, behavior, and immunity 121   122 - 141 2024年07月

ISSN  0889-1591

• Access to Document (DOI)

Glutamatergic signaling from melanin-concentrating hormone-producing neurons: A requirement for memory regulation, but not for metabolism control.

Pham XT, Abe Y, Mukai Y, Ono D, Tanaka KF, Ohmura Y, Wake H, Yamanaka A

PNAS nexus 3 （ 7 ） pgae275 2024年07月

• Access to Document (DOI)

Neurogenesis-independent mechanisms of MRI-detectable hippocampal volume increase following electroconvulsive stimulation.

Abe Y, Yokoyama K, Kato T, Yagishita S, Tanaka KF, Takamiya A

Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology 49 （ 8 ） 1236 - 1245 2024年07月

ISSN  0893-133X

• Access to Document (DOI)

Optogenetic activation of dorsal raphe serotonin neurons induces brain-wide activation.

Hamada HT, Abe Y, Takata N, Taira M, Tanaka KF, Doya K

Nature communications 15 （ 1 ） 4152 2024年05月

• Access to Document (DOI)

Brain-derived neurotrophic factor from microglia regulates neuronal development in the medial prefrontal cortex and its associated social behavior.

Komori T, Okamura K, Ikehara M, Yamamuro K, Endo N, Okumura K, Yamauchi T, Ikawa D, Ouji-Sageshima N, Toritsuka M, Takada R, Kayashima Y, Ishida R, Mori Y, Kamikawa K, Noriyama Y, Nishi Y, Ito T, Saito Y, Nishi M, Kishimoto T, Tanaka KF, Hiroi N, Makinodan M

Molecular psychiatry 29 （ 5 ） 1338 - 1349 2024年05月

ISSN  1359-4184

• Access to Document (DOI)

Neurobiological mechanisms of electroconvulsive therapy for depression: Insights into hippocampal volumetric increases from clinical and preclinical studies.

Abe Y, Erchinger VJ, Ousdal OT, Oltedal L, Tanaka KF, Takamiya A

Journal of neurochemistry 2024年01月

ISSN  0022-3042

• Access to Document (DOI)

船員健診における肝機能障害の研究

齊藤 忠範, 高木 重人, 庄田 昌隆, 櫻井 裕, 上妻 達也, 田内 潤, 笹子 佳門, 田中 謙二, 一矢 有一

海上医学研究 （(一財)船員保険会）   （ 52 ） 1 - 25 2024年01月

ISSN  0453-1000

　概要を見る

男性船員の健診受診者2636例を対象に肝機能障害の実態と要因について検討した。その結果、肝機能障害は全体で63.4%(1670例)と高頻度に認められ、うち非アルコール性脂肪性肝疾患(NAFLD)が53.1%(887/1670例)、アルコール性肝障害(ALD)が43.5%(727/1670例)と大部分を占めていた。NAFLDとALDの要因は過体重・肥満、過剰飲酒であり、また、高血圧や耐糖能異常などの生活習慣病も高頻度に認めることが明らかになった。

The differential effect of optogenetic serotonergic manipulation on sustained motor actions and waiting for future rewards in mice

Taira M., Miyazaki K.W., Miyazaki K., Chen J., Okitsu-Sakurayama S., Chaudhary A., Nishio M., Miyake T., Yamanaka A., Tanaka K.F., Doya K.

Frontiers in Neuroscience 18   1433061 2024年

ISSN  16624548

　概要を見る

Serotonin is an essential neuromodulator that affects behavioral and cognitive functions. Previous studies have shown that activation of serotonergic neurons in the dorsal raphe nucleus (DRN) promotes patience to wait for future rewards. However, it is still unclear whether serotonergic neurons also regulate persistence to act for future rewards. Here we used optogenetic activation and inhibition of DRN serotonergic neurons to examine their effects on sustained motor actions for future rewards. We trained mice to perform waiting and repeated lever-pressing tasks with variable reward delays and tested effects of optogenetic activation and inhibition of DRN serotonergic neurons on task performance. Interestingly, in the lever-pressing task, mice tolerated longer delays as they repeatedly pressed a lever than in the waiting task, suggesting that lever-pressing actions may not simply be costly, but may also be subjectively rewarding. Optogenetic activation of DRN serotonergic neurons prolonged waiting duration in the waiting task, consistent with previous studies. However, its effect on lever presses was nuanced, and was detected only by focusing on the period before premature reward check and by subtracting the trends within and across sessions using generalized linear model. While optogenetic inhibition decreased waiting, it did not affect lever pressing time or numbers. These results revealed that the necessity of motor actions may increase motivation for delayed rewards and that DRN serotonergic neurons more significantly promote waiting rather than persistent motor actions for future rewards.

• Access to Document (DOI)

Metabolites for monitoring symptoms and predicting remission in patients with depression who received electroconvulsive therapy: a pilot study

Uchida T., Sugiura Y., Sugiyama E., Maeda R., Tanaka K.F., Suematsu M., Mimura M., Uchida H.

Scientific Reports （Scientific Reports）  13 （ 1 ） 13218 2023年12月

　概要を見る

The lack of biomarkers to monitor and predict the efficacy of electroconvulsive therapy (ECT) has hindered its optimal use. To establish metabolomic markers for monitoring and predicting the treatment efficacy of ECT, we comprehensively evaluated metabolite levels in patients with major depressive disorder (MDD) by performing targeted and non-targeted metabolomic analyses using plasma samples before and after the first, third, and final ECT sessions, and 3–7 days after the final session. We compared the plasma metabolomes of age- and sex-matched healthy controls (HCs). Thirteen hospitalized patients with MDD and their corresponding HCs were included in this study. We observed that patients with MDD exhibited lower levels of amino acids, including gamma-aminobutyric acid (GABA), and metabolites involved in tryptophan metabolism and the kynurenine pathway, and higher levels of cortisol at baseline. Furthermore, we investigated the relationship between metabolite levels and depression severity across seven measurement timepoints along with one correlation analysis and found that amino acids, including GABA and tryptophan catabolites, were significantly correlated with the severity of depression. Despite the exploratory nature of this study due to the limited sample size necessitating further validation, our findings suggest that the blood metabolic profile has potential as a biomarker for ECT.

• Access to Document (DOI)

Prostaglandin E<inf>2</inf> Induces Long-Lasting Inhibition of Noradrenergic Neurons in the Locus Coeruleus and Moderates the Behavioral Response to Stressors

Mukai Y., Okubo T.S., Lazarus M., Ono D., Tanaka K.F., Yamanaka A.

Journal of Neuroscience （Journal of Neuroscience）  43 （ 47 ） 7982 - 7999 2023年11月

ISSN  02706474

　概要を見る

Neuronal activity is modulated not only by inputs from other neurons but also by various factors, such as bioactive substances. Noradrenergic (NA) neurons in the locus coeruleus (LC-NA neurons) are involved in diverse physiological functions, including sleep/wakefulness and stress responses. Previous studies have identified various substances and receptors that modulate LC-NA neuronal activity through techniques including electrophysiology, calcium imaging, and single-cell RNA sequencing. However, many substances with unknown physiological significance have been overlooked. Here, we established an efficient screening method for identifying substances that modulate LC-NA neuronal activity through intracellular calcium ([Ca21]i) imaging using brain slices. Using both sexes of mice, we screened 53 bioactive substances, and identified five novel substances: gastrin-releasing peptide, neuromedin U, and angiotensin II, which increase [Ca21]i, and pancreatic polypeptide and prostaglandin D2, which decrease [Ca21]i. Among them, neuromedin U induced the greatest response in female mice. In terms of the duration of [Ca21]i change, we focused on prostaglandin E2 (PGE2), since it induces a long-lasting decrease in [Ca21]i via the EP3 receptor. Conditional knock-out of the receptor in LC-NA neurons resulted in increased depression-like behavior, prolonged wakefulness in the dark period, and increased [Ca21]i after stress exposure. Our results demonstrate the effectiveness of our screening method for identifying substances that modulate a specific neuronal population in an unbiased manner and suggest that stress-induced prostaglandin E2 can suppress LC-NA neuronal activity to moderate the behavioral response to stressors. Our screening method will contribute to uncovering previously unknown physiological functions of uncharacterized bioactive substances in specific neuronal populations.

• Access to Document (DOI)

Shared GABA transmission pathology in dopamine agonist- and antagonist-induced dyskinesia

Abe Y., Yagishita S., Sano H., Sugiura Y., Dantsuji M., Suzuki T., Mochizuki A., Yoshimaru D., Hata J., Matsumoto M., Taira S., Takeuchi H., Okano H., Ohno N., Suematsu M., Inoue T., Nambu A., Watanabe M., Tanaka K.F.

Cell Reports Medicine （Cell Reports Medicine）  4 （ 10 ） 101208 2023年10月

　概要を見る

Dyskinesia is involuntary movement caused by long-term medication with dopamine-related agents: the dopamine agonist 3,4-dihydroxy-L-phenylalanine (L-DOPA) to treat Parkinson's disease (L-DOPA-induced dyskinesia [LID]) or dopamine antagonists to treat schizophrenia (tardive dyskinesia [TD]). However, it remains unknown why distinct types of medications for distinct neuropsychiatric disorders induce similar involuntary movements. Here, we search for a shared structural footprint using magnetic resonance imaging-based macroscopic screening and super-resolution microscopy-based microscopic identification. We identify the enlarged axon terminals of striatal medium spiny neurons in LID and TD model mice. Striatal overexpression of the vesicular gamma-aminobutyric acid transporter (VGAT) is necessary and sufficient for modeling these structural changes; VGAT levels gate the functional and behavioral alterations in dyskinesia models. Our findings indicate that lowered type 2 dopamine receptor signaling with repetitive dopamine fluctuations is a common cause of VGAT overexpression and late-onset dyskinesia formation and that reducing dopamine fluctuation rescues dyskinesia pathology via VGAT downregulation.

• Access to Document (DOI)

Starburst amacrine cells amplify optogenetic visual restoration through gap junctions.

Katada Y, Kunimi H, Serizawa N, Lee D, Kobayashi K, Negishi K, Okano H, Tanaka KF, Tsubota K, Kurihara T

Molecular therapy. Methods & clinical development （Molecular Therapy Methods and Clinical Development）  30   1 - 13 2023年09月

ISSN  2329-0501

　概要を見る

Ectopic induction of optogenetic actuators, such as channelrhodopsin, is a promising approach to restoring vision in the degenerating retina. However, the cell type-specific response of ectopic photoreception has not been well understood. There are limits to obtaining efficient gene expression in a specifically targeted cell population by a transgenic approach. In the present study, we established a murine model with high efficiency of gene induction to retinal ganglion cells (RGCs) and amacrine cells using an improved tetracycline transactivator-operator bipartite system (KENGE-tet system). To investigate the cell type-specific visual restorative effect, we expressed the channelrhodopsin gene into RGCs and amacrine cells using the KENGE-tet system. As a result, enhancement in the visual restorative effect was observed to RGCs and starburst amacrine cells. In conclusion, a photoresponse from amacrine cells may enhance the maintained response of RGCs and further increase or improve the visual restorative effect.

• Access to Document (DOI)

Brain Response to Interferential Current Compared with Alternating Current Stimulation

Xin Z., Abe Y., Kuwahata A., Tanaka K.F., Sekino M.

Brain Sciences （Brain Sciences）  13 （ 9 ）  2023年09月

ISSN  2076-3425

　概要を見る

Temporal interference (TI) stimulation, which utilizes multiple external electric fields with amplitude modulation for neural modulation, has emerged as a potential noninvasive brain stimulation methodology. However, the clinical application of TI stimulation is inhibited by its uncertain fundamental mechanisms, and research has previously been restricted to numerical simulations and immunohistology without considering the acute in vivo response of the neural circuit. To address the characterization and understanding of the mechanisms underlying the approach, we investigated instantaneous brainwide activation patterns in response to invasive interferential current (IFC) stimulation compared with low-frequency alternative current stimulation (ACS). Results demonstrated that IFC stimulation is capable of inducing regional neural responses and modulating brain networks; however, the activation threshold for significantly recruiting a neural response using IFC was higher (at least twofold) than stimulation via alternating current, and the spatial distribution of the activation signal was restricted. A distinct blood oxygenation level-dependent (BOLD) response pattern was observed, which could be accounted for by the activation of distinct types of cells, such as inhibitory cells, by IFC. These results suggest that IFC stimulation might not be as efficient as conventional brain modulation methods, especially when considering TI stimulation as a potential alternative for stimulating subcortical brain areas. Therefore, we argue that a future transcranial application of TI on human subjects should take these implications into account and consider other stimulation effects using this technique.

• Access to Document (DOI)

The gut microbiota-induced kynurenic acid recruits GPR35-positive macrophages to promote experimental encephalitis

Miyamoto K., Sujino T., Harada Y., Ashida H., Yoshimatsu Y., Yonemoto Y., Nemoto Y., Tomura M., Melhem H., Niess J.H., Suzuki T., Suzuki T., Suzuki S., Koda Y., Okamoto R., Mikami Y., Teratani T., Tanaka K., Yoshimura A., Sato T., Kanai T.

Cell Reports （Cell Reports）  42 （ 8 ） 113005 2023年08月

　概要を見る

The intricate interplay between gut microbes and the onset of experimental autoimmune encephalomyelitis (EAE) remains poorly understood. Here, we uncover remarkable similarities between CD4+ T cells in the spinal cord and their counterparts in the small intestine. Furthermore, we unveil a synergistic relationship between the microbiota, particularly enriched with the tryptophan metabolism gene EC:1.13.11.11, and intestinal cells. This symbiotic collaboration results in the biosynthesis of kynurenic acid (KYNA), which modulates the recruitment and aggregation of GPR35-positive macrophages. Subsequently, a robust T helper 17 (Th17) immune response is activated, ultimately triggering the onset of EAE. Conversely, modulating the KYNA-mediated GPR35 signaling in Cx3cr1+ macrophages leads to a remarkable amelioration of EAE. These findings shed light on the crucial role of microbial-derived tryptophan metabolites in regulating immune responses within extraintestinal tissues.

• Access to Document (DOI)

Inhibition of the dorsomedial striatal direct pathway is essential for the execution of action sequences.

Kono A, Shikano Y, Tanaka KF, Yamaura K, Tsutsui-Kimura I

Neuropsychopharmacology reports （Neuropsychopharmacology Reports）  43 （ 3 ） 414 - 424 2023年08月

　概要を見る

Contrary to the previous notion that the dorsomedial striatum (DMS) is crucial for acquiring new learning, accumulated evidence has suggested that the DMS also plays a role in the execution of already learned action sequences. Here, we examined how the direct and indirect pathways in the DMS regulate action sequences using a task that requires animals to press a lever consecutively. Cell-type-specific bulk Ca2+ recording revealed that the direct pathway was inhibited at the time of sequence execution. The sequence-related response was blunted in trials where the sequential behaviors were disrupted. Optogenetic activation at the sequence start caused distraction of action sequences without affecting motor function or memory of the task structure. By contrast with the direct pathway, the indirect pathway was slightly activated at the start of the sequence, but the optogenetic suppression of such sequence-related signaling did not impact the behaviors. These results suggest that the inhibition of the DMS direct pathway promotes sequence execution potentially by suppressing the formation of a new association.

• Access to Document (DOI)

Acceleration of the Development of Microcirculation Embolism in the Brain due to Capillary Narrowing.

Murata J, Unekawa M, Kudo Y, Kotani M, Kanno I, Izawa Y, Tomita Y, Tanaka KF, Nakahara J, Masamoto K

Stroke （Stroke）  54 （ 8 ） 2135 - 2144 2023年08月

ISSN  0039-2499

　概要を見る

BACKGROUND: Cerebral microvascular obstruction is critically involved in recurrent stroke and decreased cerebral blood flow with age. The obstruction must occur in the capillary with a greater resistance to perfusion pressure through the microvascular networks. However, little is known about the relationship between capillary size and embolism formation. This study aimed to determine whether the capillary lumen space contributes to the development of microcirculation embolism. METHODS: To spatiotemporally manipulate capillary diameters in vivo, transgenic mice expressing the light-gated cation channel protein ChR2 (channelrhodopsin-2) in mural cells were used. The spatiotemporal changes in the regional cerebral blood flow in response to the photoactivation of ChR2 mural cells were first characterized using laser speckle flowgraphy. Capillary responses to optimized photostimulation were then examined in vivo using 2-photon microscopy. Finally, microcirculation embolism due to intravenously injected fluorescent microbeads was compared under conditions with or without photoactivation of ChR2 mural cells. RESULTS: Following transcranial photostimulation, the stimulation intensity-dependent decrease in cerebral blood flow centered at the irradiation was observed (14%-49% decreases relative to the baseline). The cerebrovascular response to photostimulation showed significant constriction of the cerebral arteries and capillaries but not of the veins. As a result of vasoconstriction, a temporal stall of red blood cell flow occurred in the capillaries of the venous sides. The 2-photon excitation of a single ChR2 pericyte demonstrated the partial shrinkage of capillaries (7% relative to the baseline) around the stimulated cell. With the intravenous injection of microbeads, the occurrence of microcirculation embolism was significantly enhanced (11% increases compared to the control) with photostimulation. CONCLUSIONS: Capillary narrowing increases the risk of developing microcirculation embolism in the venous sides of the cerebral capillaries.

• Access to Document (DOI)

Pupil Dynamics-derived Sleep Stage Classification of a Head-fixed Mouse Using a Recurrent Neural Network.

Kobayashi G, Tanaka KF, Takata N

The Keio journal of medicine （Keio Journal of Medicine）  72 （ 2 ） 44 - 59 2023年06月

ISSN  0022-9717

　概要を見る

The standard method for sleep state classification is thresholding the amplitudes of electroencepha-lography (EEG) and electromyography (EMG) data, followed by manual correction by an expert. Al-though popular, this method has some shortcomings: (1) the time-consuming manual correction by human experts is sometimes a bottleneck hindering sleep studies, (2) EEG electrodes on the skull interfere with wide-field imaging of the cortical activity of a head-fixed mouse under a microscope, (3) invasive surgery to fix the electrodes on the thin mouse skull risks brain tissue injury, and (4) metal electrodes for EEG and EMG recording are difficult to apply to some experimental apparatus such as that for functional magnetic resonance imaging. To overcome these shortcomings, we propose a pupil dynamics-based vigilance state classification method for a head-fixed mouse using a long short-term memory (LSTM) model, a variant of a recurrent neural network, for multi-class labeling of NREM, REM, and WAKE states. For supervisory hypnography, EEG and EMG recording were performed on head-fixed mice. This setup was combined with left eye pupillometry using a USB camera and a markerless tracking toolbox, DeepLabCut. Our open-source LSTM model with feature inputs of pupil diameter, pupil location, pupil velocity, and eyelid opening for 10 s at a 10 Hz sampling rate achieved vigilance state estimation with a higher classification performance (macro F1 score, 0.77; accuracy, 86%) than a feed-forward neural network. Findings from a diverse range of pupillary dynamics implied possible subdivi-sion of the vigilance states defined by EEG and EMG. Pupil dynamics-based hypnography can expand the scope of alternatives for sleep stage scoring of head-fixed mice.

• Access to Document (DOI)

Mesolimbic dopamine release precedes actively sought aversive stimuli in mice.

Yawata Y, Shikano Y, Ogasawara J, Makino K, Kashima T, Ihara K, Yoshimoto A, Morikawa S, Yagishita S, Tanaka KF, Ikegaya Y

Nature communications （Nature Communications）  14 （ 1 ） 2433 2023年04月

　概要を見る

In some models, animals approach aversive stimuli more than those housed in an enriched environment. Here, we found that male mice in an impoverished and unstimulating (i.e., boring) chamber without toys sought aversive air puffs more often than those in an enriched chamber. Using this animal model, we identified the insular cortex as a regulator of aversion-seeking behavior. Activation and inhibition of the insular cortex increased and decreased the frequencies of air-puff self-stimulation, respectively, and the firing patterns of insular neuron ensembles predicted the self-stimulation timing. Dopamine levels in the ventrolateral striatum decreased with passive air puffs but increased with actively sought puffs. Around 20% of mice developed intense self-stimulation despite being offered toys, which was prevented by administering opioid receptor antagonists. This study establishes a basis for comprehending the neural underpinnings of usually avoided stimulus-seeking behaviors.

• Access to Document (DOI)