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Kato, A.

Publications and source records attributed to Kato, A..

At least 37 records · Page 2Linked to original sources

Requirement for Fucosyltransferase 2 in Allergic Airway Hyperreactivity and Mucus Obstruction

Mucus hypersecretion is an important pathological problem in respiratory diseases. Mucus accumulates in the airways of people with asthma, and it contributes to airflow limitation by forming plugs that occlude airways. Current treatments have minimal effects on mucus or its chief components, the polymeric mucin glycoproteins MUC5AC and MUC5B. This treatment gap reflects a poor molecular understanding of mucins that could be used to determine how they contribute to airway obstruction. Due to the prominence of glycosylation as a defining characteristic of mucins, we investigated characteristics of mucin glycans in asthma and in a mouse model of allergic asthma. Mucin fucosylation was observed in asthma, and in healthy mice it was induced as part of a mucous metaplastic response to allergic inflammation. In allergically inflamed mouse airways, mucin fucosylation was dependent on the enzyme fucosyltransferase 2 (Fut2). Fut2 gene deficient mice were protected from asthma-like airway hyperreactivity and mucus plugging. These findings provide mechanistic and translational links between observations in human asthma and a mouse model that may help improve therapeutic targeting of airway mucus.

physiology↗

Human Substantia Nigra Neurons Encode Reward Expectations

Dopamine (DA) signals originating from substantia nigra (SN) neurons are centrally involved in the regulation of motor and reward processing. DA signals behaviorally relevant events where reward outcomes differ from expectations (reward prediction errors, RPEs). RPEs play a crucial role in learning optimal courses of action and in determining response vigor when an agent expects rewards. Nevertheless, how reward expectations, crucial for RPE calculations, are conveyed to and represented in the dopaminergic system is not fully understood, especially in the human brain where the activity of DA neurons is difficult to study. One possibility, suggested by evidence from animal models, is that DA neurons explicitly encode reward expectations. Alternatively, they may receive RPE information directly from upstream brain regions. To address whether SN neuron activity directly reflects reward expectation information, we directly examined the encoding of reward expectation signals in human putative DA neurons by performing single-unit recordings from the SN of patients undergoing neurosurgery. Patients played a two-armed bandit decision- making task in which they attempted to maximize reward. We show that neuronal firing rates (FR) of putative DA neurons during the reward expectation period explicitly encode reward expectations. First, activity in these neurons was modulated by previous trial outcomes, such that FR were greater after positive outcomes than after neutral or negative outcome trials. Second, this increase in FR was associated with shorter reaction times, consistent with an invigorating effect of DA neuron activity during expectation. These results suggest that human DA neurons explicitly encode reward expectations, providing a neurophysiological substrate for a signal critical for reward learning.

neuroscience↗

Selectivity and evolution of Aqp10 in solute permeability influenced by pore molecular weight

Aqp10 is an aquaglyceroporin that transports not only water but also uncharged low-molecular-weight compounds. We previously demonstrated the evolution of solute permeability in Aqp10 paralogs and showed that the urea and boric acid permeabilities of Aqp10.2 were much weaker than those of Aqp10.1 and plesiomorphic Aqp10s. However, the molecular mechanism responsible for the weak permeability of Aqp10.2 to urea and boric acid remains unclear. Herein, we present a novel hypothesis that explains the solute selectivity of Aqp10. We deduced the ancestral sequences of Aqp10.1 and Aqp10.2 paralogs via molecular phylogenetic analysis. Constructed structural models of these sequences revealed that both the well known amino acid site at position 3 and the sum of molecular weights of the four amino acid sites in the ar/R region were important for the formation of the Aqp10 selectivity filter. Site-directed mutagenesis revealed that a decrease in the sum of the molecular weights of the four amino acid sites enhanced the Aqp10 permeability to urea and boric acid. Based on this, we proposed a model in which the presence of two or more bulky amino acids in the ar/R region, which increases the sum of the molecular weights of amino acids in the ar/R region, was essential for the formation of a filter that limited urea and boric acid transport. Our results outline the molecular mechanism by which Aqp10.2 acquired a selectivity filter during evolution and provide structural insights into the narrowly tuned filter responsible for the solute selectivity of aquaglyceroporins. Significance StatementIn aquaglyceroporins, particularly Aqp10s, the urea and boric acid permeabilities of Aqp10.2 paralogs are much weaker than those of plesiomorphic Aqp10s. Here, we deduced the ancestral sequences of Aqp10.1 and Aqp10.2 via molecular phylogenetic analysis. Structural models of these sequences revealed that the sum of the four amino acid site molecular weights in the ar/R region, if more than one is bulky, contributed to the selectivity filter formation in the pore region. Using site-directed mutagenesis, reduction in the molecular weight of one bulky amino acid residue in the ar/R region restricted urea and boric acid permeability. Therefore, Aqp10.2 acquired a selectivity filter during evolution, and structural differences in this selectivity filter are responsible for the variable solute permeability of aquaglyceroporins.

physiology↗

Comparative analyses of adsorbed circulating proteins in the PMMA and PES hemodiafilters in patients on predilution online hemodiafiltration

Acute and chronic inflammation are common in patients with end-stage kidney disease (ESKD). So, the adsorption of pro-inflammatory cytokines by the hollow fiber has been expected to modify the inflammatory dysregulation in ESKD patients. However, it remains to be determined in detail what molecules of fiber materials can preferably adsorb proteins from the circulating circuit. We aimed this study to analyze directly the adsorbed proteins in the polymethyl methacrylate (PMMA) and polyethersulfone (PES) membranes in patients on predilution online hemodiafiltration (OL-HDF). To compare the adsorbed proteins in the PMMA and PES hemodiafilters membrane, we initially performed predilution OL-HDF using the PES (MFX-25Seco) membrane while then switched to the PMMA (PMF-A) membrane under the same condition in three patients. We extracted proteins from the collected hemodiafilters by extraction, then SDS-PAGE of the extracted sample, protein isolation, in-gel tryptic digestion, and nano-LC MS/MS analyses. The concentrations of adsorbed proteins from the PMMA and PES membrane extracts were 35.6{+/-}7.9 {micro}g/{micro}L and 26.1{+/-}9.2 {micro}g/{micro}L. SDS-PAGE analysis revealed distinct variations of adsorbed proteins mainly in the molecular weight between 10 to 25 kDa. By tryptic gel digestion and mass spectrometric analysis, the PMMA membrane exhibited higher adsorptions of {beta}2 microglobulin, dermcidin, retinol-binding protein-4, and lambda-1 light chain than those from the PES membrane. In contrast, amyloid A-1 protein was adsorbed more potently in the PES membrane. Western blot analyses revealed that the PMMA membrane adsorbed interleukin-6 (IL-6) approximately 5 to 118 times compared to the PES membrane. These findings suggest that PMMA-based OL-HDF therapy may be useful in controlling inflammatory status in ESKD patients.

pathology↗

Penguin tracking data for effective conservation in marine spatial planning

Understanding the spatial-temporal marine habits is crucial to conserving air-breathing marine animals that breed on islands and forage at sea. This study, focusing on little penguins from Phillip Island, Australia, employed tracking data to identify vital foraging areas during breeding season. Long-term data from sub-colonies and breeding stages were analysed using 50%, 75%, and 90% kernel utilisation distributions (KUDs). Breeding success, classified as low, average, or high, guided the exploration of site, year, and breeding stage-specific habitats. Using Marxan, a widely used conservation planning tool, the study proposes both static and dynamic spatial-temporal scenarios for protection based on KUDs. The dynamic approach, requiring less space than the static strategy, was more efficient and likely more acceptable to stakeholders. The study underscores the need for comprehensive data in conservation plans, as relying on one nesting sites data might miss essential foraging areas for penguins in other locations. This study demonstrates the efficacy of animal tracking data in spatial conservation prioritisation and marine spatial planning. The dynamic areas frequented emerged as a strategy to safeguard core regions at sea, offering insights to improve the conservation of iconic species like little penguins and promoting the health of islands and the entire marine ecosystem.

ecology↗

Regulatory Mimicry of Cyclin-Dependent Kinases by Conserved Herpesvirus Protein Kinases

Herpesviruses encode conserved protein kinases (CHPKs) that target cellular cyclin-dependent kinase (CDK) phosphorylation sites; thus, they are termed viral CDK-like kinases. Tyrosine 15 in the GxGxxG motifs of CDK1 and CDK2, whose phosphorylation down-regulates their catalytic activities, is conserved in the corresponding motifs of CHPKs. We found that herpes simplex virus 2 (HSV-2) CHPK UL13 mimicked the regulatory mechanism of CDKs. This regulatory mimicry was conserved in CHPKs encoded by herpesviruses subclassified into subfamilies other than HSV-2, suggesting CHPKs have regulatory and functional mimicry with CDKs. Phosphorylation of the corresponding Tyr in HSV-2 UL13 was required for the down-regulation of viral replication and pathogenicity, specifically in the central nervous system of mice, and for efficient viral recurrence in guinea pigs. These data highlight the dual impact of the regulatory mimicry of CDKs by CHPK on the fine-tuned regulation of lytic and latent HSV-2 infections in vivo.

microbiology↗

Decoding Ten Years of Little Penguin Foraging: Bio-Logging Reveals Foraging Patterns with Implications for Climate Change Mitigation and Marine Spatial Planning

O_LIProtected areas are a widely adopted resource management strategy for mitigating the consequences of global change and preserve functioning ecosystems. Long-term species monitoring programmes, aided by bio-logging technology, provide insights into the extent and spatial variation of areas occupied by wild animals and inform conservation and management. High-resolution GPS-acceleration data offer a more accurate understanding of animal behavior and area use, compared to location-based inference, emphasizing the significance of specific sites amid long-term climate change. C_LIO_LIWe based our case-study on the largest colony of little penguins (Eudyptula minor) located at Phillip Island. Based on a ten-year bio-logging dataset (247 individual tracks), we combine high-resolution bio-logging data from GPS-accelerometer loggers with proxies for resource availability (e.g. Sea Surface Tenperature, thermocline, water turbidity). Using machine learning techniques and Generalized Additive Mixed Models, we quantify the environmental factors determining spatio-temporal variability in foraging effort (defined as hunting time) across different breeding seasons and stages. C_LIO_LILittle penguins increased their hunting time by reducing spatial displacement (shorter step length) and diving deeper, with a slower increase in hunting effort below 10 m depth. In relation to environmental conditions, penguins increased hunting effort in coastal areas with high turbid and productive waters and decreased effort with increasing Sea Surface Temperature. This gives insights into how these animals allocate effort differently according to shifting environmental conditions. C_LIO_LIOur analysis offers crucial long-term insights into little penguin area usage in the Bass Strait at sufficient spatial and temporal resolution for management and conservation planning. The Bass Strait is facing intense climatic and anthripogenic pressures, and the findings here on intensity of area usage and strategy shifting according to environmental conditions, are of great relevance for the marine spatial planning currently under development along the coast. C_LIO_LIPolicy implications: High-resolution behavioral information obtained from bio-logging data using GPS-accelerometer tags provides understanding of how species shift strategies in response to environmental variability. This is vital to implement climate-adaptive conservation and management strategies. Given the growing availability of long-term accelerometer datasets within the ecological community, we recommend integrating such high-resolution information into conservation programs. C_LI

ecology↗

Production of Infectious Reporter Murine Norovirus by VP2 trans-Complementation

Human norovirus (HuNoV) causes gastroenteritis, a disease with no effective therapy or vaccine. Murine norovirus (MNV) easily replicates in cell culture and small animals and has often been used as a model to elucidate the structural and functional characteristics of HuNoV. A MNV plasmid-based reverse genetics system was developed to produce modified recombinant virus. In this study, we attempted to construct the recombinant virus by integrating a foreign gene into MNV ORF3 that encodes the minor structural protein VP2. We found that deletion of VP2 expression abolished infectious particles from MNV cDNA clones, and supplying exogenous VP2 to the cells rescued the infectivity of cDNA clones without VP2 expression. In addition, we found that the coding sequence of C-terminal ORF3 was essential for cDNA clones compensated with VP2 to produce infectious particles. Further, the recombinant virus with exogenous reporter genes in place of the dispensable ORF3 coding region was able to propagate when VP2 was constitutively supplied. Our findings indicate that foreign genes can be transduced into the norovirus ORF3 region when VP2 is supplied and that successive propagation of modified recombinant norovirus could lead to the development of norovirus-based vaccines or therapeutics. IMPORTANCEIn this study, we revealed that some of the coding regions of ORF3 could be replaced by foreign gene and infectious virus could be produced under conditions with VP2 supplied. Propagation of this virus depended on VP2 being supplied in trans, indicating that this virus could infect only once. Our findings help to elucidate the functions of VP2 in virus lifecycle and to the development of other caliciviral vectors for recombinant attenuated live enteric virus vaccines or therapeutics.

microbiology↗

COVID-related anthropause highlights the impact of marine traffic on breeding little penguins

The COVID-19 pandemic and its lock-down measures have resulted in periods of reduced human activity, known as anthropause. While this period was expected to be favorable for the marine ecosystem, due to a probable reduction of pollution, shipping traffic, industrial activity and fishing pressure, negative counterparts such as the increased use of disposable plastic and reduced fisheries surveillance and enforcement could counterbalance these positive effects. Simultaneously, on-land pressure due to human disturbance and tourism should have drastically decreased, potentially benefiting land-based marine breeders such as seabirds. Thus, long-term datasets became crucial to differentiate between historical trends and any evident changes resulting from the anthropause. We analyzed 11 years of data on several biological parameters of little penguins (Eudyptula minor) from the Penguin Parade (R), a popular tourist attraction at Phillip Island, Australia. We investigated the impact of anthropogenic activities on penguin behavior during the breeding season measured by (1) distribution at sea, (2) colony attendance, (3) isotopic niche (4) chick meal mass, and (5) offspring investment against shipping traffic and number of tourists. The 2020 lock-downs resulted in a near absence of tourists visiting the Penguin Parade (R), which was otherwise visited by 800,000+ visitors on average per year. However, our long-term analysis showed no effect of the presence of visitors on little penguins activities. Surprisingly, the anthropause did not triggered any changes in maritime traffic intensity and distribution in the region. While we found significant inter- and intra-annual variations for most parameters, we detected a negative effect of marine traffic on the foraging efficiency. Our results suggest that environmental variations have a greater influence on the breeding behavior of little penguins compared to short-term anthropause events. Our long-term dataset was key to test whether changes in anthropogenic activities affected the wildlife during the COVID-19 pandemic. Impact statementWe found that marine traffic, but not tourist presence, negatively impact the foraging and provisioning behavior of little penguins.

ecology↗

Evasion of APOBEC1-mediated Intrinsic Immunity by a Herpesvirus Uracil DNA Glycosylase Is a Determinant of Viral Encephalitis

Herpes simplex virus 1 (HSV-1) is the most common cause of viral encephalitis, which can be lethal or result in severe neurological defects, even when treated with antiviral therapy. We demonstrated that activation of HSV-1 uracil-DNA glycosylase (vUNG) by phosphorylation, essential for its enzymatic activity, counteracted APOBEC1 to promote viral replication and encephalitis in the central nervous system (CNS) of mice. The activation of vUNG protected HSV-1 genomes from APOBEC1-mediated DNA editing, allowing efficient viral replication to occur. The presence of APOBEC1 markedly improved lethal encephalitis in mice infected with an HSV-1 mutant carrying a mutation in the phosphorylation site and an UNG inhibitor protected wild-type HSV-1-infected mice from lethal encephalitis. These findings re-define vUNG as an important factor that allows evasion from intrinsic anti-viral immunity mediated by APOBEC1 in the CNS, and suggest a new therapeutic approach for the treatment of fetal and critical HSV-1 encephalitis.

microbiology↗

Direct Relationship between Protein Expression and Progeny Yield of Herpes Simplex Virus 1 Unveils a Rate-limiting Step for Virus Production

Although viral protein expression and progeny virus production were independently shown to be highly heterogenous in individual cells, their direct relationship, analyzed by considering their heterogeneities, has not been investigated to date. This study established a system to fractionate cells infected with a herpesvirus based on the levels of the global expression of viral late proteins, which are largely virion structural proteins, and to titrate virus yields in these fractions. This system demonstrated a direct relationship and indicated there was a threshold for the levels of viral late protein expression for progeny virus production and suggested that viral DNA cleavage/packaging was a rate-limiting step for progeny virus production. These findings, which were masked in previous studies performed at the entire population level, have uncovered a sophisticated viral strategy for efficient progeny virus production and shed new light on an effective target for the development of anti-viral drugs.

microbiology↗

Dual Impacts of a Glycan Shield on the Envelope Glycoprotein B of HSV-1: Evasion from Human Antibodies In Vivo and Neurovirulence

Identification of the mechanisms of viral evasion from human antibodies is crucial both for understanding viral pathogenesis and for designing effective vaccines. However, the in vivo efficacy of the mechanisms of viral evasion from human antibodies has not been well documented. Here we show in cell cultures that an N-glycan shield on the HSV-1 envelope glycoprotein B (gB) mediated evasion from neutralization and antibody-dependent cellular cytotoxicity due to pooled {gamma}-globulins derived from human blood. We also demonstrated that the presence of human {gamma}-globulins in mice and HSV-1 immunity induced by viral infection in mice significantly reduced the replication of a mutant virus lacking the glycosylation site in a peripheral organ but had little effect on the replication of its repaired virus. These results suggest that the glycan shield on the HSV-1 envelope gB mediated evasion from human antibodies in vivo and from HSV-1 immunity induced by viral infection in vivo. Notably, we also found that the glycan shield on HSV-1 gB was significant for HSV-1 neurovirulence and replication in the central nervous system (CNS) of naive mice. Thus, we have identified a critical glycan shield on HSV-1 gB that has dual impacts, namely evasion from human antibodies in vivo and viral neurovirulence. IMPORTANCEHSV-1 establishes lifelong latent and recurrent infections in humans. To produce recurrent infections that contribute to transmission of the virus to new human host(s), the virus must be able to evade the antibodies persisting in latently infected individuals. Here we show that an N-glycan shield on the envelope glycoprotein B of HSV-1 mediates evasion from pooled {gamma}-globulins derived from human blood both in cell cultures and mice. Notably, the N-glycan shield was also significant for HSV-1 neurovirulence in naive mice. Considering the clinical features of HSV-1 infection, these results suggest that the glycan shield not only facilitates recurrent HSV-1 infections in latently infected humans by evading antibodies, but is also important for HSV-1 pathogenesis during the initial infection.

microbiology↗

Neonatal Fc receptor is a functional receptor for human astrovirus

Human astrovirus (HAstV) is a global cause of gastroenteritis in infants, the elderly, and immunocompromised people. However, its infection mechanism is not fully understood, with its functional receptor not yet discovered. Here, we identify neonatal Fc receptor (FcRn) as a functional receptor for HAstV (mamastrovirus 1) using genome-wide CRISPR-Cas9 library screening in Caco2 cells. Deletion of FCGRT or B2M, which encode subunits of FcRn, rendered Caco2 cells and intestinal organoid cells unsusceptible to HAstV. We also show that human FcRn expression renders non-permissive MDCK cells susceptible and that FcRn directly binds HAstV spike protein. Thus, our findings provide insight into the entry mechanism of HAstV.

microbiology↗

Dopaminergic neurons dynamically update sensory values during navigation

Updating the value of sensory cues through experiences is a critical element of adaptive behavior. Although dopaminergic neurons (DANs) achieve this by driving associative learning, whether they contribute to assessment of sensory values outside the context of association remains largely unexplored. Here we show in Drosophila that DANs in the mushroom body encode the innate value of odors and constantly update the current value by inducing plasticity during olfactory navigation. Simulation of neuronal activity in a network based on the connectome data reproduced the characteristics of DAN responses, proposing a concrete circuit mechanism for computation. Notably, odors alone induced value- and dopamine-dependent changes in the activity of mushroom body output neurons, which store the current value of odors, as well as the behavior of flies steering in a virtual environment. Thus, the DAN circuit known for discrete, associative learning also continuously updates odor values during navigation in a non-associative manner.

neuroscience↗

Estimating the distribution of livestock in space and time: a time-series contribution to livestock density mapping

More than one billion people rely on livestock for income, nutrition, and social cohesion, however livestock keeping can facilitate disease transmission and contribute to climate change. While data on the distribution of livestock thus have broad utility across a range of applications, efforts to map the distribution of livestock on a large scale are limited to the Gridded Livestock of the World (GLW) project. We present a complimentary effort to map the distribution of cattle and pigs in Malawi, Uganda, Democratic Republic of Congo (DRC), and South Sudan. In contrast to GLW, which uses dasymmetric modeling applied to census data to produce time-stratified estimates of livestock counts and spatial density, our work uses complex survey data and distinct modeling methods to generate a time-series of livestock distribution, defining livestock density as the ratio of animals to humans. In addition to favorable cross-validation results and general agreement with national density estimates derived from external data on national human and livestock populations, our results demonstrate extremely good agreement with GLW-3 estimates, supporting the validity of both efforts. Our results furthermore offer a high-resolution time series result and employ a definition of density which is particularly well-suited to the study of livestock-origin zoonoses.

ecology↗

Placental mammals acquired the functional region and domain in NRK for regulating the CK2-PTEN-AKT pathway and placental cell proliferation

The molecular evolution processes underlying the acquisition of the placenta in eutherian ancestors are not fully understood. Mouse NCK-interacting kinase (NIK)-related kinase (NRK) is expressed highly in the placenta and plays a role in preventing placental hyperplasia. Here, we show the molecular evolution of NRK, which confers its function for inhibiting placental cell proliferation. Comparative genome analysis identified NRK orthologues across vertebrates, which share the kinase and citron homology (CNH) domains. Evolutionary analysis revealed that NRK underwent extensive amino acid substitutions in the ancestor of placental mammals and has been since conserved. Biochemical analysis of mouse NRK revealed that the CNH domain binds to phospholipids, and a region in NRK binds to and inhibits casein kinase-2 (CK2), which we named the CK2-inhibitory region (CIR). Cell culture experiments suggest the following: (1) mouse NRK is localised at the plasma membrane via the CNH domain, where the CIR inhibits CK2. (2) This mitigates CK2-dependent phosphorylation and inhibition of PTEN, and (3) leads to the inhibition of AKT signalling and cell proliferation. Nrk deficiency increased phosphorylation levels of PTEN and AKT in mouse placenta, supporting our hypothesis. Unlike mouse NRK, chicken NRK did not bind to phospholipids and CK2, decrease phosphorylation of AKT, or inhibit cell proliferation. Both the CNH domain and CIR have evolved under purifying selection in placental mammals. Taken together, our study suggests that placental mammals acquired the phospholipid-binding CNH domain and CIR in NRK for regulating the CK2-PTEN-AKT pathway and placental cell proliferation.

molecular biology↗

The molecular basis of ubiquitin-specific protease 8 autoinhibition by the WW-like domain

Ubiquitin-specific protease 8 (USP8) is a deubiquitinating enzyme involved in multiple membrane trafficking pathways. The enzyme activity is inhibited by binding to 14-3-3 proteins, and mutations of the 14-3-3 binding motif in USP8 are related to Cushings disease. However, the molecular basis of USP8 enzyme activity regulation remains unclear. Here, we identified amino acids 645-684 of USP8 as an autoinhibitory region, which our pull-down and single-molecule FRET assay results suggested interacts with the catalytic USP domain. In silico modelling indicated that the region forms a WW-like domain structure, plugs the catalytic cleft, and narrows the entrance to the ubiquitin-binding pocket. Furthermore, 14-3-3 was found to inhibit USP8 enzyme activity partly by enhancing the interaction between the WW-like and USP domains. These findings provide the molecular basis of USP8 autoinhibition via the WW-like domain. Moreover, they suggest that the release of autoinhibition may underlie Cushings disease caused by USP8 mutations.

biochemistry↗

Effects of species traits and ecosystem characteristics on species detection by eDNA metabarcoding in lake fish communities

Although environmental DNA (eDNA) metabarcoding is acknowledged to be an exceptionally useful and powerful tool for monitoring surveys, it has limited applicability, particularly for nationwide surveys. To evaluate the performance of eDNA metabarcoding in broad-scale monitoring, we examined the effects of species ecological/biological traits and ecosystem characteristics on species detection rates and the consequences for community analysis. We conducted eDNA metabarcoding on fish communities in 18 Japanese lakes on a country-wide scale. By comparing species records, we found that certain species traits, including body size, body shape, saltwater tolerance, and habitat preferences, influenced eDNA detection. We also found that the proportion of species detected decreased significantly with an increase in lake surface area, owing to an ecosystem-size effect on species detection. We conclude that species traits, including habitat preferences and body size, and ecosystem size should be taken into consideration when assessing the performance of eDNA metabarcoding in broad-scale monitoring.

ecology↗