Biology subjects

Takeda, A.

Publications and source records attributed to Takeda, A..

13 recordsLinked to original sources

bioRxiv2026

Adenosine impairs T cell function via activation of purine salvage pathway and AMP-induced inhibition of pyrimidine nucleotide biosynthesis

Extracellular adenosine (ADO) is a well-established immune checkpoint mediator suppressing T cells via activation of A2A receptors, yet intracellular mechanisms of ADO action remain less understood. Here, we show that activated human T cells transport extracellular ADO through equilibrative nucleoside transporter 1 (ENT1) and metabolize it through ATP salvage pathway. The generated ADO metabolite AMP inhibits UMP synthase (UMPS), the rate-limiting enzyme of de novo pyrimidine biosynthesis, leading to diminished ATP production via conventional bioenergetic pathways, increased apoptosis, and impaired effector functions of T cells. Flow cytometric and single-cell transcriptomic analyses further revealed that ADO restrains the exit of naive T cells from quiescence. All effects of ADO were phenocopied by treating T cells with the inhibitors of UMPS and reversed after pharmacological blockage of ENT1 or uridine supplementation. Additional molecular docking, molecular dynamics simulations, and free-energy analyses indicate that AMP can occupy the orotidine 5'-monophosphate (OMP) decarboxylase catalytic site of UMPS with the same anchoring contacts as substrate OMP and product UMP, providing a structural rationale for direct AMP-mediated inhibition of pyrimidine biosynthesis. These findings demonstrate that immunosuppressive effects of ADO extend beyond canonical adenosinergic signaling and involve cellular ADO uptake and modulation of purine and pyrimidine metabolism.

immunology↗

bioRxiv2026

The Lateral Protein Cluster as a Key Component of Plant Cell Polarity

Cell polarity is an ancient organizing principle across kingdoms. As in animal epithelial cells, plant cells asymmetrically distribute proteins to establish functionally distinct membrane domains. In roots, radial polarity distinguishes inner and outer cell surfaces and supports directional nutrient transport, yet its molecular basis remains poorly understood. Here, we show that the leucine-rich repeat receptor-like kinases CaMRLK and IRK occupy complementary lateral plasma membrane domains in Arabidopsis thaliana roots. Polarity-guided proximity labeling identified previously uncharacterized proteins associated with inner- and outer-lateral domains. Clade VII LRR-RLKs, protein S-acyltransferases, SICK, IRKI1, and a distinct group of NPH3/RPT2-LIKEs assemble into the Lateral Protein Cluster (LPC) through multivalent interactions. LPC components are conserved across land plants, and disruption of NRL function impairs morphogenesis in Arabidopsis and Marchantia polymorpha. Together, these findings establish the LPC as an evolutionarily conserved molecular machinery linking radial cell polarity to plant morphogenesis.

plant biology↗

bioRxiv2026

BWR-finder: BWT-based de novo interspersed repeat detection for gigantic genomes

We developed BWR-finder (Burrows-Wheeler transform-based Repeat finder), a new software tool for database-free detection of interspersed repeats in large genomes of tens of gigabases. BWR-finder employs a BWT-based seed-and-extend repeat detection algorithm and parallelized extension computation, improving both runtime and memory usage. In benchmarks using the rice and human genomes, BWR-finder reduced runtime compared with RepeatModeler2, HiTE, and REPrise, and reduced memory usage compared with HiTE and REPrise, while maintaining high nucleotide-level repeat detection sensitivity. BWR-finder also enabled whole-genome repeat detection in genomes larger than 10 Gb and identified candidate repeat regions and repeat consensus sequences in the 20.3-Gb Pleurodeles waltl genome that were not associated with existing repeat annotations or libraries.

bioinformatics↗

bioRxiv2026

Outperforming the Majority-Rule Consensus Tree Using Fine-Grained Dissimilarity Measures

Phylogenetic analyses often require the summarization of multiple trees, e.g., in Bayesian analyses to obtain the centroid of the posterior distribution of trees, or to determine the consensus of a set of bootstrap trees. The majority-rule consensus tree is the most commonly used. It is easy to compute and minimizes the sum of Robinson-Foulds (RF) distances to the input trees. In mathematical terms, the majority-rule consensus tree is the median of the input trees with respect to the RF distance. However, due to the coarse nature of RF distance, which only considers whether two branches induce exactly the same bipartition of the taxa or not, highly unresolved trees can be produced when the phylogenetic signal is low. To overcome this limitation, we propose using median trees with respect to finer-grained dissimilarity measures between trees. These measures include a quartet distance between tree topologies, and transfer distances, which quantify the similarity between bipartitions, in contrast to the 0/1 view of RF. We describe fast heuristic consensus algorithms for transfer-based tree dissimilarities, capable of efficiently processing trees with thousands of taxa. Through evaluations on simulated datasets in both Bayesian and bootstrapping maximum-likelihood frameworks, our results show that our methods improve consensus tree resolution in scenarios with low to moderate phylogenetic signal, while providing better or comparable dissimilarities to the true phylogeny. Applying our methods to Mammal phylogeny and a large HIV dataset of over nine thousand taxa confirms the improvement with real data. These results demonstrate the usefulness of our new consensus tree methods for analyzing the large datasets that are available today. Our software, PhyloCRISP, is available from https://github.com/yukiregista/PhyloCRISP.

bioinformatics↗

bioRxiv2024

Breast Cancer Remodels Lymphatics in Sentinel Lymph Nodes

Cancer metastasis to sentinel lymph nodes (LNs) is often the first marker of potential disease progression. Although it is recognized that tumor-induced lymphangiogenesis facilitates metastasis into LNs in murine models, tumor-induced alterations in human lymphatic vessels remain obscure. We used single-cell RNA sequencing to profile lymphatic endothelial cell (LEC) subsets in paired metastatic and non-metastatic LNs obtained from patients with treatment-naive breast cancer. Tumor metastasis decreases immunoregulatory LEC subsets, such as PD-L1+ subcapsular sinus LECs, while inducing an increase in capillary-like CD200+ HEY1+ LECs. Matrix Gla protein (MGP) was the most upregulated gene in metastatic LN LECs, and its expression on LECs was TGF-{beta} and VEGF dependent. Upregulated MGP promotes cancer cell adhesion to LN lymphatics. Thus, breast cancer cell metastasis to LNs remodels LEC subsets in human LNs and escalates MGP expression, potentially facilitating cancer cell dissemination through the lymphatic system.

immunology↗

bioRxiv2024

Microtubules ensure transport of vegetative nuclei and sperm cells by fine-tuning their home positions

The pollen tube plays a pivotal role in double fertilization by delivering sperm cells (SCs) to the ovule. In Arabidopsis thaliana, a pair of SCs tightly connects with the vegetative nucleus (VN) to form the male germ unit (MGU), which is located in the apical region during pollen-tube growth, keeping the VN ahead of the SCs. MGU transport relies on independent motility of VN and SC pairs. However, the complexity of this dual motive force has hindered our understanding of MGU behavior, including its positioning and nuclear order. We used Arabidopsis mutants or transgenic plants that produced semi-motile MGUs with aberrant VNs or SCs to analyze the positioning of VN or SCs after stochastically disconnecting the MGU. In pollen tubes with an immotile SC pair, the VN was [~]70 m away from the tip, whereas in pollen tubes with an immotile VN, the SC pair was [~]100 m away from the tip, implying that the VN and SCs have independent home positions. The position of MGU moved forward owing to the loss of the microtubule-destabilizing kinesin KINESIN-13A. Conversely, microtubule depolymerization by oryzalin treatment or introducing mutations in TUBULIN BETA 4 (TUB4) deregulated the position of the MGU and shifted its position backward. In addition, tub4 plants exhibited reduced fertility. These data indicate a significant role of microtubules in stable MGU positioning to ensure reproductive success.

plant biology↗

bioRxiv2024

REPrise: de novo interspersed repeat detection using inexact seeding

MotivationInterspersed repeats occupy a large part of many eukaryotic genomes, and thus their accurate annotation is essential for various genome analyses. Database-free de novo repeat detection approaches are powerful for annotating genomes that lack well-curated repeat databases. However, existing tools do not yet have sufficient repeat detection performance. ResultsIn this study, we developed REPrise, a de novo interspersed repeat detection software program based on a seed-and-extension method. Although the algorithm of REPrise is similar to that of RepeatScout, which is currently the de facto standard tool, we incorporated three unique techniques into REPrise: inexact seeding, affine gap scoring and loose masking. Analyses of rice and simulation genome datasets showed that REPrise outperformed RepeatScout in terms of sensitivity, especially when the repeat sequences contained many mutations. Furthermore, when applied to the complete human genome dataset T2T-CHM13, REPrise demonstrated the potential to detect novel repeat sequence families. AvailabilityThe source code of REPrise is freely available at https://github.com/hmdlab/REPrise. Repeat annotations predicted for the T2T genome using REPrise are also available at https://waseda.box.com/v/REPrise-data. Contactfukunaga@aoni.waseda.jp and mhamada@waseda.jp

bioinformatics↗

bioRxiv2023

Atf3 controls transitioning in female mitochondrial cardiomyopathy as identified by single-cell transcriptomics

Oxidative phosphorylation defects results in mitochondrial diseases, with cardiac involvement markedly impacting prognosis. However, the mechanisms underlying the transition from compensation to dysfunction in response to metabolic deficiency remain unclear, impeding the development of effective treatments. Here, we employed single-nucleus RNA sequencing (snRNA-seq) on hearts from mitochondrial cardiomyopathy (MCM) mice with cardiac-specific Ndufs6 knockdown (FS6KD). Pseudotime trajectory analysis of cardiomyocytes from early stage of female FS6KD hearts revealed dynamic cellular state transitioning from compensation to severe compromise, coincided with transient upregulation of a critical transcription factor, activating transcription factor 3 (Atf3). Genetic ablation or adeno-associated virus-mediated Atf3 knockdown in FS6KD mice effectively delayed cardiomyopathy progression in a female-specific manner. Notably, human MCM snRNA-seq revealed a similar transition, including the dynamic expression of ATF3. In conclusion, our findings highlight a fate-determining role of Atf3 in female MCM progression, providing a promising therapeutic candidate for the currently intractable disease.

cell biology↗

bioRxiv2022

Mobile elements in human population-specific genome and phenotype divergence

Mobile genetic elements (MEs) are heritable mutagens that contribute to divergence between lineages by recursively generating structural variants. ME variants (MEVs) are difficult to genotype, obscuring their impact on recent genome and trait diversification. We developed a tool that uses short-read sequence data to accurately genotype MEVs, enabling us to study them using statistical genetics methods in global human genomes. We observe population-specific differences in the distribution of Alu insertions that distinguish Japanese from other populations. We integrated MEVs with epigenomic and expression quantitative trait loci (eQTL) maps to determine how they impact traits. This reveals coherent patterns by which specific MEs regulate tissue-specific gene expression, including creating or attenuating enhancers and recruiting post-transcriptional regulators. We pinpoint MEVs as genetic causes of disease risk, including a LINE-1 insertion linked to keloid and other diseases of fibroblast inflammation, by introducing MEVs into the genome-wide association study (GWAS) framework. In addition to nominating previously-hidden MEVs as causes of human diseases, this work highlights MEs as accelerators of human population divergence and begins to decipher the semantics of MEs.

genetics↗

bioRxiv2021

A versatile Tn7 transposon-based bioluminescence tagging tool for quantitative and spatial detection of bacteria in plants

Investigation of plant-bacteria interactions requires quantification of in planta bacterial titers by means of colony counting assays. However, colony counting assays are cumbersome and time-consuming, and are unable to detect spatial patterns of bacterial colonization in plants. Here, to overcome these shortcomings, we devised a broadly applicable genetic engineering tool for bioluminescence-based quantitative and spatial detection of bacteria in plants. We developed plasmid vectors that have broad host ranges and enable Tn7 transposon-mediated integration of the luxCDABE luciferase operon into a specific genomic location ubiquitously found across bacterial phyla. These vectors allowed for generation of bioluminescent transformants of various plant pathogenic bacteria belonging to the genera Pseudomonas, Rhizobium (Agrobacterium), and Ralstonia. The bioluminescent transformant of Pseudomonas syringae pv. tomato DC3000 (Pto-lux) was as virulent in Arabidopsis thaliana as its parental strain. Direct luminescence measurements of Pto-lux-inoculated plant tissues reported bacterial titers in A. thaliana, Solanum lycopersicum, Nicotiana benthamiana, and Marchantia polymorpha as accurately as conventional colony counting assays. We further showed the utility of our vectors for converting the previously generated Pto derivatives to isogenic bioluminescent strains. Importantly, quantitative bioluminescence assays using these Pto-lux strains accurately reported the effects of plant immunity and bacterial effectors on bacterial growth with a dynamic range of 4 orders of magnitude. Moreover, macroscopic bioluminescence imaging illuminated spatial colonization patterns of the Pto-lux in/on inoculated plant tissues. Taken together, our vectors offer untapped opportunities for developing bioluminescence-based quantitative and spatial analysis of bacterial growth in a variety of plant-bacteria interactions. SIGNIFICANCE STATEMENTWe developed broad-host-range plasmid vectors that integrate the luciferase operon, luxCDABE, into a specific genomic location ubiquitously found across bacterial phyla. Using these vectors, we established a high-throughput method for bioluminescence-based quantitative assays of in planta bacterial growth with a dynamic range of 4 orders of magnitude and visualized spatiotemporal patterns of bacterial colonization in/on inoculated plant tissues.

plant biology↗

bioRxiv2020

Ribosome stalling caused by the Argonaute-miRNA-SGS3 complex regulates production of secondary siRNA biogenesis in plants

The path of ribosomes on mRNAs can be impeded by various obstacles. One such example is halting of ribosome movement by microRNAs, though the exact mechanism and physiological role remain unclear. Here, we find that ribosome stalling caused by the Argonaute-microRNA-SGS3 complex regulates the production of secondary small interfering RNAs (siRNAs) in plants. We show that the double-stranded RNA-binding protein SGS3 directly interacts with the 3' end of the microRNA in an Argonaute protein, resulting in ribosome stalling. Importantly, microRNA-mediated ribosome stalling positively correlates with efficient production of secondary siRNAs from target mRNAs. Our results illustrate a role for paused ribosomes in regulation of small RNA function that may have broad biological implications across the plant kingdom.

molecular biology↗

bioRxiv2020

A single-cell transcriptional roadmap of the mouse and human lymph node lymphatic vasculature

Single-cell transcriptomics promises to revolutionize our understanding of the vasculature. Emerging computational methods applied to high dimensional single cell data allow integration of results between samples and species, and illuminate the diversity and underlying developmental and architectural organization of cell populations. Here, we illustrate these methods in analysis of mouse lymph node (LN) lymphatic endothelial cells (LEC) at single cell resolution. Clustering identifies five well-delineated subsets, including two medullary sinus subsets not recognized previously as distinct. Nearest neighbor alignments in trajectory space position the major subsets in a sequence that recapitulates known and suggests novel features of LN lymphatic organization, providing a transcriptional map of the lymphatic endothelial niches and of the transitions between them. Differences in gene expression reveal specialized programs for (1) subcapsular ceiling endothelial interactions with the capsule connective tissue and cells, (2) subcapsular floor regulation of lymph borne cell entry into the LN parenchyma and antigen presentation, and (3) medullary subset specialization for pathogen interactions and LN remodeling. LEC of the subcapsular sinus floor and medulla, which represent major sites of cell entry and exit from the LN parenchyma respectively, respond robustly to oxazolone inflammation challenge with enriched signaling pathways that converge on both innate and adaptive immune responses. Integration of mouse and human single-cell profiles reveals a conserved cross-species pattern of lymphatic vascular niches and gene expression, as well as specialized human subsets and genes unique to each species. The examples provided demonstrate the power of single-cell analysis in elucidating endothelial cell heterogeneity, vascular organization and endothelial cell responses. We discuss the findings from the perspective of LEC functions in relation to niche formations in the unique stromal and highly immunological environment of the LN. Highlights Computational alignments ("trajectories") predict LN LEC organization in situ, revealing a continuum of phenotypes punctuated by specialized clusters Multiple intermediate phenotypes suggest LEC malleability Gene profiles define niche-specific functional specialization Medullary sinus LECs are comprised of Ptx3-LECs and Marco-LECs O_LIDistinct mechanisms for pathogen interactions and matrix modeling C_LIO_LIPtx3-LECs: paracortical and central medullary sinuses near hilus; enriched for genes driving lymphangiogenic responses and lymphocyte egress C_LIO_LIMarco-LECs: peri-follicular medullary sinuses; macrophage-associated genes, complement and coagulation cascade C_LI Niche-specific responses to inflammation O_LIIFN gene responses in SCS floor and medullary sinus LECs C_LIO_LISuppression of LEC identity genes in responding subsets C_LI Conserved and unique LEC subsets and gene programs across species O_LICore subsets common to mouse and human C_LIO_LIGreater diversity of subsets and intermediates in human LN LECs C_LI

systems biology↗

bioRxiv2019

Identification of 15 new bypassable essential genes of fission yeast

Every organism has a different set of genes essential for its viability. This indicates that an organism can become tolerant to the loss of an essential gene under certain circumstances during evolution, via the manifestation of masked alternative mechanisms. In our quest to systematically uncover masked mechanisms in eukaryotic cells, we developed an extragenic suppressor screening method using haploid spores deleted of an essential gene in the fission yeast Schizosaccharomyces pombe. We screened for the bypass suppressors of lethality of 92 randomly selected genes that are essential for viability in standard laboratory culture conditions. Remarkably, extragenic mutations bypassed the essentiality of as many as 20 genes (22%), 15 of which have not been previously reported. Half of the bypass-suppressible genes were involved in mitochondria function; we also identified multiple genes regulating RNA processing. 18 suppressible genes were conserved in the budding yeast Saccharomyces cerevisiae, but 13 of them were non-essential in that species. These trends are consistent with a recent independent bypass-of-essentiality (BOE) screening of 142 fission yeast genes conducted with more elaborate methodology (Li et al., 2019). Thus, our study reinforces the emerging view that BOE is not a rare event and that each organism may be endowed with secondary or backup mechanisms that can substitute for primary mechanisms in various biological processes. Furthermore, the robustness of our simple spore-based methodology paves the way for genome-scale BOE screening.

genetics↗