Biology subjects

Morishita, H.

Publications and source records attributed to Morishita, H..

15 recordsLinked to original sources

bioRxiv2026

Nicotinic modulation of frontal circuits breaks the cycle of attentional performance failure

The ability to recover from consecutive failures is critical for adaptive behavior, yet the underlying neural mechanisms remain unclear. In vivo screening of neuromodulatory inputs onto frontal-sensory cognitive control circuit identified a frontal cholinergic mechanism that counteracts lapses in attentional engagement following repeated errors. Cholinergic input from the basal forebrain to the frontal cortex was necessary and sufficient to restore performance after errors, specifically after repeated-but not after a single-failure. This effect was mediated by 7-nicotinic acetylcholine receptors in frontal-sensory cortical neurons, which sustained cortical circuit activity and frontal-sensory cortical oscillations during attentional engagement. Targeted optogenetic activation of these frontal-sensory neurons disrupted cycles of attentional performance failure and reinstated behavioral performance in a mouse model of neuropsychiatric syndrome. These findings reveal a circuit-level mechanism of cholinergic control that confers cognitive resilience under conditions of persistent failure.

neuroscience↗

bioRxiv2026

High basal autophagic activity in the brain revealed by systemic quantitative analysis using GFP-LC3-RFP mice

Autophagy is a fundamental intracellular degradation pathway with vital physiological functions. Although it is well known that autophagy is activated during starvation, the extent of basal autophagy remains unclear owing to challenges in measuring autophagic flux in vivo. In this study, we developed autophagy reporter (GFP-LC3-RFP) mice and quantified basal autophagic flux across tissues by comparing normal and autophagy-deficient conditions. Comparative analyses revealed uniformly low basal autophagic flux during embryogenesis, but significant tissue-specific variation in adult mice. In contrast to previous assumptions that basal autophagy in the brain is low, the brain, along with the liver and kidney, exhibited higher basal autophagic flux than the heart, skeletal muscle, and intestine. These data serve as foundational information on basal autophagic flux in mammals and provide a plausible explanation for the severe neurological phenotypes linked to autophagy gene mutations in mice and humans.

cell biology↗

bioRxiv2025

Low-salinity medium for large-scale biomass production of the marine purple photosynthetic bacterium Rhodovulum sulfidophilum

Marine purple non-sulfur bacteria such as Rhodovulum sulfidophilum are versatile due to their diverse applications in bioremediation, biotechnological production of useful materials, industrial production of value-added compounds, and agricultural fertilizers. Our previous study demonstrated the potential of its lysed and dried biomass as a nitrogen fertilizer for plant production. However, large-scale fertilizer production requires scaling up the culture to larger volumes, which is not cost-effective with currently available options for growth media. In this study, we tested a seawater-based, cost-effective alternative to the commonly used nutrient-rich culture medium for the growth of this bacterium. We found that reducing salinity from 3% to 1.2% had no adverse effects on its heterotrophic growth, dry cell yield, nitrogen content, and total amino acid composition. The nitrogen content and the weight percent of free lysine, aspartic acid, and glutamate increased in the biomass obtained from cultures grown at 1.2% salinity. Under autotrophic conditions, decreasing salinity to 1.2% did not affect cell growth, final dry cell yields, and total carbon assimilation, but N assimilation tended to be higher. Reducing salinity to 1.2% proved to be cost-effective and feasible for the cultivation of R. sulfidophilum without increasing the risk of contamination, providing a viable alternative for its large-scale cultivation and application as a plant nitrogen fertilizer.

microbiology↗

bioRxiv2025

KEAP1 retention in phase-separated p62 bodies drives liver damage in autophagy-deficient conditions

Phase-separated p62 bodies activate NRF2, a key transcription factor for antioxidant response, by sequestering KEAP1, which targets NRF2 for degradation. Although p62 bodies containing KEAP1 are degraded by autophagy, they accumulate in various liver disorders. Their precise disease role remains unclear. We show that excessive KEAP1 retention in p62 bodies and NRF2 activation are major causes of liver damage when autophagy is impaired. In mice with weakened or blocked p62-KEAP1 interactions, KEAP1 retention and NRF2 activation under autophagy-deficient conditions were suppressed. Transcriptome and proteome analyses revealed that NRF2 targets upregulated by autophagy suppression normalized in p62 mutants unable to bind KEAP1. Autophagy deficiency caused organelle accumulation, especially of the ER, regardless of p62 mutation. Liver damage and hepatomegaly from autophagy suppression markedly improved in p62 mutants, particularly those with blocked KEAP1 binding. These findings highlight excessive KEAP1 retention in p62 bodies and defective organelle turnover as key drivers of liver pathology, underscoring the significance of phase separation in vivo.

cell biology↗

bioRxiv2025

Altered kinship vocal dynamics in marmosets with valproic acid-induced model of autism

Autism spectrum disorder (ASD) is characterised by social communication impairments and repetitive behaviours. Language deficits, including echolalia and restricted vocabulary, heighten caregiver stress and negatively affect the familys quality of life. Although animal models have advanced the understanding of individual ASD traits, their influence on kinship dynamics remains underexplored. To address this issue, we developed a clinically relevant ASD model in common marmosets by prenatal exposure to valproic acid (VPA) to produce ASD-like pups alongside their typically developing parents. We analysed 28,418 kinship calls from nine VPA-exposed and seven unexposed (UE) pups, along with their parents. Kinship vocalisations in VPA families exhibited significant alterations, including increased isolation calls, decreased affiliative calls, disruption of structured repetition patterns, and reduced developmental maturations. These deviations intensified after weaning, suggesting a link between social communicative stressors and altered family dynamics. Parental weight loss was correlated with kinship vocal deviations, potentially reflecting increased caregiver stress. This observation aligns with clinical reports of heightened stress in families raising children with ASD. VPA pups also displayed premature locomotion independence, indicating broader social and communication disruptions. These findings suggest that VPA marmosets are valuable models for investigating ASD-like traits in individuals and kinship-level dynamics. Kinship vocalisations provide critical insights into the interplay between communication impairments and caregiver stress, offering a promising avenue for developing non-invasive biomarkers for ASD-related challenges.

neuroscience↗

bioRxiv2024

Live-cell imaging and CLEM reveal the existence of ACTN4-dependent ruffle-edge lamellipodia acting as a novel mode of cell migration

-Actinin-4 (ACTN4) expression levels are correlated with the invasive and metastatic potential of cancer cells; however, the underlying mechanism remains unclear. Here, we identified ACTN4-localized ruffle-edge lamellipodia using live-cell imaging and correlative light and electron microscopy (CLEM). BSC-1 cells expressing EGFP-ACTN4 showed that ACTN4 was most abundant in the leading edges of lamellipodia, although it was also present in stress fibers and focal adhesions. ACTN4 localization in lamellipodia was markedly diminished by phosphoinositide 3-kinase inhibition, whereas its localization in stress fibers and focal adhesions remained. Furthermore, overexpression of ACTN4, but not ACTN1, promoted lamellipodial formation. Live-cell analysis demonstrated that ACTN4-enriched lamellipodia are highly dynamic and associated with cell migration. CLEM revealed that ACTN4-enriched lamellipodia exhibit a characteristic morphology of multilayered ruffle-edges that differs from canonical flat lamellipodia. Similar ruffle-edge lamellipodia were observed in A549 and MBA-MD-231 invasive cancer cells. ACTN4 knockdown suppressed the formation of ruffle-edge lamellipodia and cell migration during wound healing in A549 monolayer cultures. Additionally, membrane-type 1 matrix metalloproteinase was observed in the membrane ruffles, suggesting that ruffle-edge lamellipodia have the ability to degrade the extracellular matrix and may contribute to active cell migration/invasion in certain cancer cell types.

cell biology↗

bioRxiv2024

Transcriptional landscape of the dorsal raphe serotonin neurons rendering stress resiliency

Major depressive disorder (MDD) is a serious and large social problem, yet the pathophysiology of MDD and the action mechanism of antidepressants are still poorly understood. A number of studies have reported that activation and inactivation of serotonin neurons in the dorsal raphe nucleus (DRN) cause antidepressant-like effects and depressive-like behaviors, respectively. Also, their physiological neural activities are increased when mice were chronically administered an SSRI and decreased in mice exposed to chronic social defeat stress (CSDS), a mouse model of depression. However, the molecular mechanism underlying these neural activity changes in DRN serotonin neurons remains unclear. In this study, we performed a DRN serotonin neuron-specific comprehensive gene expression analysis by using Translating Ribosome Affinity Purification (TRAP) technology in both chronic SSRI-treated mice as a model of antidepressant treatment and CSDS mice as a model of depression. It revealed that many gene expression changes were the opposite between SSRI-treated mice and CSDS-susceptible mice. Among these, we identified S100a10 as a prodepressive gene in DRN serotonin neurons, and we found that Interleukin-4 (IL-4) - Signal Transducer and Activator of Transcription 6 (STAT6) pathway and 5-HT1B receptor were the upstream and downstream molecules of S100a10, respectively. Our findings provide insights into molecular mechanisms underlying the action of antidepressants and stress resiliency.

pharmacology and toxicology↗

bioRxiv2022

Phosphorylation of phase-separated p62 bodies by ULK1 activates a redox-independent stress response

NRF2 is a transcription factor responsible for antioxidant stress responses that is usually regulated in a redox-dependent manner. p62 bodies formed by liquid-liquid phase separation contain Ser349-phosphorylated p62, which participates in the redox-independent activation of NRF2. However, the regulatory mechanism and physiological significance of phosphorylation remain unclear. Herein, we identify ULK1 as a kinase responsible for phosphorylation of p62. ULK1 co-localizes with p62 bodies, and directly interacts with p62. This phosphorylation allows KEAP1 to be retained within p62 bodies, activating NRF2. p62S351E/+ mice are phosphomimetic knock-in mice in which Ser351 corresponding to human Ser349 is replaced by Glu. These mice, but not phosphodefective p62S351A/S351A mice, exhibit NRF2 hyperactivation and growth retardation, the latter caused by malnutrition and dehydration due to obstruction of the esophagus and forestomach secondary to hyperkeratosis. p62S351E/+ mice are a phenocopy of systemic Keap1-knockout mice. Our results expand our understanding of the physiological importance of the redox-independent NRF2 activation pathway and provide new insight into the role of phase separation in this process.

cell biology↗

bioRxiv2021

Task Demand-dependent Contribution of Frontal-Sensory Cortical Projections to Attentional Behavior in Mice

Top-down attention is a dynamic cognitive process that facilitates the detection of the task-relevant stimuli from our complex sensory environment. A neural mechanism capable of deployment under specific task-demand conditions would be crucial to efficiently control attentional processes and improve promote goal-directed attention performance during fluctuating attentional demand. Previous studies have shown that frontal top-down neurons projecting from the anterior cingulate area (ACA) to the visual cortex (VIS; ACAVIS) are required for visual attentional behavior during the 5-choice serial reaction time task (5CSRTT) in mice. However, it is unknown whether the contribution of these projecting neurons is dependent on the extent of task demand. Here, we first examined how behavior outcomes depend on the number of locations for mice to pay attention and touch for successful performance, and found that the 2-choice serial reaction time task (2CSRTT) is less task demanding than the 5CSRTT. We then employed optogenetics to demonstrate that suppression ACAVIS projections immediately before stimulus presentation has no effect during the 2CSRTT in contrast to the impaired performance during the 5CSRTT. These results suggest that ACAVIS projections are necessary when task demand is high, but once a task demand is lowered, ACAVIS neuron activity becomes dispensable to adjust attentional performance. These findings support a model that the frontal-sensory ACAVIS projection regulates visual attention behavior during specific high task demand conditions, pointing to a flexible circuit-based mechanism for promoting attentional behavior.

neuroscience↗

bioRxiv2020

Evolution and insights into the structure and function of the DedA superfamily containing TMEM41B and VMP1

TMEM41B and VMP1 are endoplasmic reticulum (ER)-localizing multi-spanning membrane proteins required for ER-related cellular processes such as autophagosome formation, lipid droplet homeostasis, and lipoprotein secretion in eukaryotes. Both proteins have a VTT domain, which is similar to the DedA domain found in bacterial DedA family proteins. However, the molecular function and structure of the DedA and VTT domains (collectively referred to as DedA domains) and the evolutionary relationships among the DedA domain-containing proteins are largely unknown. Here, we conduct remote homology search and identify a new clade consisting mainly of bacterial PF06695 proteins of unknown function. Phylogenetic analysis reveals that the TMEM41, VMP1, DedA, and PF06695 families form a superfamily with a common origin, which we term the DedA superfamily. Coevolution-based structural prediction suggests that the DedA domain contains two reentrant loops that face each other in the membrane. This topology is biochemically verified by the substituted cysteine accessibility method. The predicted structure is topologically similar to that of the substrate-binding region of Na+-coupled glutamate transporter solute carrier 1. A potential ion-coupled transport function of the DedA superfamily proteins is discussed.

cell biology↗

bioRxiv2020

An adolescent sensitive period of heightened frontal top-down projection activity promotes local circuit integration and attentional behavior

Frontal top-down cortical neurons projecting to sensory cortical regions are well-positioned to integrate long-range inputs with local circuitry in frontal cortex to implement top-down attentional control of sensory regions. How adolescence contributes to the maturation of top-down neurons and associated local/long-range input balance, and the establishment of attentional control is poorly understood. Here we combine projection-specific electrophysiological and rabies-mediated input mapping in mice to uncover adolescence as a developmental stage when frontal top-down neurons projecting from the anterior cingulate to visual cortex are highly functionally integrated into local excitatory circuitry and have heightened activity compared to adulthood. Chemogenetic suppression of top-down neuron activity selectively during adolescence, but not later periods, produces long-lasting visual attentional behavior deficits, and results in excessive loss of local excitatory inputs in adulthood. Our study reveals an adolescent sensitive period when top-down neurons integrate local circuits with long-range connectivity to produce attentional behavior.

neuroscience↗

bioRxiv2020

Gastrointestinal absorption of pimozide is enhanced by inhibition of P-glycoprotein

Following the death due to cardiac arrest of a patient taking pimozide, sertraline and aripiprazole antipsychotic/antidepressant combination therapy, a role of drug-drug interaction was suggested. Here, we investigated P-glycoprotein (P-gp)-mediated interaction among the three drugs using in vitro methods. Sertraline or aripiprazole significantly increased the permeability of pimozide in Caco-2 cell monolayers. ATPase assay indicated that pimozide is a P-gp substrate, and might act as a P-gp inhibitor at higher concentrations. The values of the kinetic parameters of carrier-mediated efflux, calculated from the concentration dependence of pimozide efflux from LLC-GA5-COL150 cells expressing human P-gp, were as follows: maximum transport rate (Jmax) = 84.9 {+/-} 8.9 pmol/min/mg protein, half-saturation concentration (Kt) = 10.6 {+/-} 4.7 M, first-order rate constant (kd) = 0.67 {+/-} 0.14 pmol/min/mg protein. Further, the efflux ratio of pimozide in LLC-GA5-COL150 cells was significantly decreased in the presence of sertraline or aripiprazole. These results indicate that pimozide is a substrate of P-gp, and its efflux is inhibited by sertraline and aripiprazole. Thus, P-gp inhibition by sertraline and/or aripiprazole may alter the gastrointestinal permeability of co-administered pimozide, resulting in an increased blood concentration of pimozide, which may increase the likelihood of pimozides known life-threatening side effect of QT prolongation.

pharmacology and toxicology↗

bioRxiv2019

Disruption of the CSF-1-CSF-1R axis alters cerebellar microglia and is associated with motor and social interaction defects

Microglia, the brain resident macrophages, critically shape forebrain neuronal circuits. However, their precise function in the cerebellum is unknown. Here we show that human and mouse cerebellar microglia express a unique molecular program distinct from forebrain microglia. Cerebellar microglial identity was driven by the CSF-1R ligand CSF-1, independently of the alternate CSF-1R ligand, IL-34. Accordingly, CSF-1 depletion from Nestin+ cells led to severe depletion and transcriptional alterations of cerebellar microglia, while microglia in the forebrain remained intact. Strikingly, CSF-1 deficiency and alteration of cerebellar microglia were associated with reduced Purkinje cells, altered neuronal function, and defects in motor learning and social novelty interactions. These findings reveal a novel CSF-1-CSF-1R signaling-mediated mechanism that contributes to motor function and social behavior.\n\nSummaryMicroglia are a heterogeneous population whose identity and function are dictated by signals from their microenvironment. Kana et al. show that CSF-1 signaling is critical for maintaining cerebellar microglial transcriptional identity and homeostasis, and that altering the CSF-1 - CSF-1R axis leads to motor and behavioral defects.

neuroscience↗

bioRxiv2019

Early life stress alters transcriptomic patterning across reward circuitry in male and female mice

Abuse, neglect, and other forms of early life stress (ELS) significantly increase risk for psychiatric disorders including depression. In this study, we show that ELS in a postnatal sensitive period increases sensitivity to adult stress in female mice, consistent with our earlier findings in male mice. We used RNA-sequencing in the ventral tegmental area, nucleus accumbens, and prefrontal cortex of male and female mice to show that adult stress is distinctly represented in the brains transcriptome depending on ELS history. We identify: 1) biological pathways disrupted after ELS and associated with increased behavioral stress sensitivity, 2) putative transcriptional regulators of the effect of ELS on adult stress response, and 3) subsets of primed genes specifically associated with latent behavioral changes. We also provide transcriptomic evidence that ELS increases sensitivity to future stress through enhancement of known programs of cortical plasticity.

neuroscience↗

bioRxiv2017

Activation of Somatostatin Inhibitory Neurons by Lypd6-nAChRα2 System Restores Juvenile-like Plasticity in Adult Visual Cortex

The limitation of plasticity in the adult brain impedes functional recovery later in life from brain injury or disease. This pressing clinical issue may be resolved by enhancing plasticity in the adult brain. One strategy for triggering robust plasticity in adulthood is to reproduce one of the hallmark physiological events of experience-dependent plasticity observed during the juvenile critical period - rapidly reduce the activity of parvalbumin (PV)-expressing interneurons and disinhibit local excitatory neurons. This may be achieved through enhancement of local inhibitory inputs, particularly those of somatostatin (SST)-expressing interneurons. However, to date the means for manipulating SST interneurons for enhancing cortical plasticity in the adult brain are not known. We show that SST interneuron-selective overexpression of Lypd6, an endogenous nicotinic signaling modulator, enhances ocular dominance plasticity in the adult primary visual cortex (V1). Lypd6 overexpression mediates a rapid experience-dependent increase in the visually evoked activity of SST interneurons as well as a simultaneous reduction in PV interneuron activity and disinhibition of excitatory neurons. Recapitulating this transient activation of SST interneurons using chemogenetics similarly enhanced V1 plasticity. Notably, we show that SST-selective Lypd6 overexpression restores visual acuity in amblyopic mice that underwent early long-term monocular deprivation. Our data in both male and female mice reveal selective modulation of SST interneurons and a putative downstream circuit mechanism as an effective method for enhancing experience-dependent cortical plasticity as well as functional recovery in adulthood. Significance StatementThe decline of cortical plasticity after closure of juvenile critical period consolidates neural circuits and behavior, but this limits functional recovery from brain diseases and dysfunctions in later life. Here we show that activation of cortical SST interneurons by Lypd6, an endogenous modulator of nicotinic acetylcholine receptors (nAChRs), enhances experience-dependent plasticity and recovery from amblyopia in adulthood. This manipulation triggers rapid reduction of PV interneuron activity and disinhibition of excitatory neurons, which are known hallmarks of cortical plasticity during juvenile critical periods. Our study demonstrates modulation of SST interneurons by Lypd6 to achieve robust levels of cortical plasticity in the adult brain and may provide promising targets for restoring brain function in the event of brain trauma or disease.

neuroscience↗