Biology subjects

Kawaoka, S.

Publications and source records attributed to Kawaoka, S..

9 recordsLinked to original sources

bioRxiv2026

The vagus nerve drives cognitive function through the default mode network

The afferent vagus nerve transmits interoceptive signals to the brain but a systematic understanding of how vagal signals affect brain-wide neuronal dynamics remains elusive. Here, comprehensive spatiotemporal analyses across the entire mouse brain revealed that vagus nerve stimulation activated neuronal ensembles within the default mode network (DMN). In contrast, vagal-independent mechanisms predominantly affected the salience network. The vagal-DMN association was mediated by locus coeruleus neuronal subpopulations. Selective activation or silencing of vagal-responsive DMN neuronal ensembles replicated or abolished VNS-induced enhancement of cognitive behaviors and progressive problem-solving behaviors. These findings establish a unifying framework for how the vagus nerve drives cognitive functions by engaging the DMN.

neuroscience↗

bioRxiv2026

DeepSpaceDB 2.0: an interactive spatial transcriptomics database for large-scale Xenium data exploration

The 10x Genomics Xenium platform enables high-resolution spatial transcriptomics at single-cell and subcellular scales, but effective reuse of public Xenium datasets is hindered by large data sizes and heterogeneous file formats. We previously developed DeepSpaceDB, a spatial transcriptomics database designed for interactive, in-depth analysis of tissues and tissue microenvironments. Here, we present a major expansion of DeepSpaceDB that integrates large-scale single-cell spatial transcriptomics data generated by the Xenium platform. In this update, we systematically collected 1,539 public Xenium datasets from multiple repositories and processed them through a robust, standardized pipeline that validates, repairs, and harmonizes heterogeneous inputs into a unified representation. To support efficient exploration of these data, we introduced a redesigned DeepSpaceDB interface and complementary Zarr-based storage formats optimized for gene-centric visualization and spatially localized queries, enabling sub-second response times for common interactive operations. The updated platform supports real-time visualization of spatial data and analysis of regions of interest directly in the web browser. Together, this expansion establishes DeepSpaceDB as a unified resource for single-cell spatial transcriptomics, substantially lowering the barrier to accessing, exploring, and reusing large-scale public Xenium datasets.

bioinformatics↗

bioRxiv2025

DeepSpaceDB: a spatial transcriptomics atlas for interactive in-depth analysis of tissues and tissue microenvironments

Spatial transcriptomics provides a revolutionary approach to mapping gene expression within tissues, offering critical insights into the spatial organization of cellular and molecular processes. However, generating new spatial transcriptomics data is expensive and technically demanding, and analyzing such data requires advanced bioinformatics expertise. While publicly available datasets are growing rapidly, existing databases offer limited tools for interactive exploration and cross-sample comparisons. Here, we introduce DeepSpaceDB, a next-generation spatial transcriptomics database designed to address these issues. DeepSpaceDB focuses on interactivity and advanced analytical functionality, enabling users to explore spatial transcriptomics data with unprecedented flexibility. DeepSpaceDB allows for interactive selection and comparison of gene expression across regions within a single tissue slice or between slices, such as comparing hippocampal regions of an Alzheimers model mouse and a control. It also includes quality indicators, database-wide trends, and advanced visualizations that provide real-time interactivity, such as zoomable plots and hover-based information display. Moreover, these functions are not restricted to the samples collected in our database but can also be applied to samples uploaded by users. The current version of DeepSpaceDB focuses explicitly on samples of the 10X Genomics Visium platform, ensuring higher-quality analyses and enhanced exploration tools, including comparison between interactively selected regions of tissue sections. This tradeoff enables unique features like similarity-based sample embeddings and database-wide comparisons, setting it apart from other databases prioritizing broad platform coverage over functionality. With its combination of advanced tools and interactive capabilities, DeepSpaceDB represents a transformative resource for spatial transcriptomics research, paving the way for deeper insights into tissue organization and disease biology. Availability: DeepSpaceDB is available at www.deepspacedb.com.

bioinformatics↗

bioRxiv2023

Low albumin status accompanies multi-layered immunosuppressive phenotypes in metastatic breast cancer patients

Low albumin status is prevalent in advanced cancer patients, but the pathophysiology associated with this anomaly remains largely unexplored. To address this, we aim to search correlations of albumin levels with the transcriptome against peripheral blood mononuclear cells and the plasma metabolome within the same patients having metastatic breast cancers. We confirm that metastatic breast cancer patients exhibit low albumin levels in varying degrees without prominent systemic inflammation. Our data demonstrate that low albumin levels correlate with transcriptome signatures indicative of "neutrophil activation and T-cell down-regulation," an immunosuppressive phenotype. We also find that immunoregulatory metabolites, such as arginine, are reduced in plasma in an albumin-correlated manner, further corroborating systemic immunosuppression. These results are verified using a mouse model of breast cancer. We conclude that low albumin status in metastatic breast cancer patients accompanies immunosuppressive phenotypes, which is likely unfavorable for anti-cancer immunotherapy and thus can be a cause of unsuccessful treatment outcomes.

cancer biology↗

bioRxiv2023

Selective elimination of CD169+ macrophages in lymph nodes invaded by breast cancers

Breast cancer cells suppress the host immune system to efficiently invade the lymph nodes; however, the underlying mechanism remains incompletely understood. Here, we report that metastasized breast cancer cells selectively eliminate CD169+ lymph node sinus macrophages, an initiator of anti-cancer immunity, from the lymph nodes. The comparison between paired lymph nodes with and without metastasis from the same patients demonstrated that the number of CD169+ macrophages was reduced in metastatic lymph nodes, whereas the numbers of other major immune cell types were unaltered. We also detected the infiltration of CD169+ macrophages into metastasized cancer tissues depending on sections, suggesting that CD169+ macrophages were gradually eliminated after anti-cancer reactions. Furthermore, CD169+ macrophage elimination was prevalent in major breast cancer subtypes and correlated with breast cancer staging. Collectively, we propose that metastasized breast cancer cells dispel CD169+ macrophages from lymph nodes in a phased manner, disabling a critical step of anti-cancer immunity.

cancer biology↗

bioRxiv2022

Serum amyloid alpha 1-2 are not required for systemic inflammation in the 4T1 murine breast cancer model

Cancers induce the production of acute phase proteins such as serum amyloid alpha (SAA) in the liver and cause systemic inflammation. Despite the well-known coincidence of acute phase response and systemic inflammation, the direct roles of SAA proteins in systemic inflammation in the cancer context remains incompletely characterized, particularly in vivo. Here, we investigate the in vivo significance of SAA proteins in systemic inflammation in the 4T1 murine breast cancer model. 4T1 cancers elevate the expression of SAA1 and SAA2, the two major murine acute phase proteins in the liver. The elevation of Saa1-2 correlates with the up-regulation of immune cell-related genes including neutrophil markers. To examine this correlation in detail, we generate mice that lack Saa1-2 and investigate immune-cell phenotypes. RNA-seq experiments reveal that deletion of Saa1-2 does not strongly affect 4T1-induced activation of immune cell-related genes in the liver and bone marrow. Flow cytometry experiments demonstrate the dispensable roles of SAA1-2 in cancer-dependent neutrophil infiltration to the liver. This study clarifies the negligible contribution of SAA1-2 proteins in systemic inflammation in the 4T1 breast cancer model.

cancer biology↗

bioRxiv2022

Murine breast cancers disorganize the liver transcriptome in zonated manners

The spatially organized gene expression program within the liver specifies hepatocyte functions according to their relative distances to the bloodstream (i.e., zonation), contributing to liver homeostasis. Despite the knowledge that solid cancers remotely disrupt liver homeostasis, it remains unexplored whether solid cancers affect liver zonation. Here, using spatial transcriptomics, we thoroughly investigate the abundance and zonation of hepatic genes in cancer-bearing mice. We find that breast cancers affect liver zonation in various distinct manners depending on biological pathways. Aspartate metabolism and triglyceride catabolic processes retain relatively intact zonation patterns, but the zonation of xenobiotic catabolic process genes exhibits a strong disruption. The acute phase response is induced in zonated manners. Furthermore, we demonstrate that breast cancers activate innate immune cells in particular neutrophils in distinct zonated manners, rather than in a uniform fashion within the liver. Collectively, breast cancers disorganize hepatic transcriptomes in zonated manners, thereby disrupting zonated functions of the liver.

cancer biology↗

bioRxiv2022

Nicotinamide-N-methyltransferase is essential for SAM and 1-methylnicotinamide homeostasis in the AML12 hepatocyte cell line

Nicotinamide-N-methyltransferase (NNMT) is an enzyme that consumes S-adenosyl-methionine (SAM) and nicotinamide (NAM) to produce S-adenosyl-homocysteine (SAH) and 1-methylnicotinamide (MNAM). How much NNMT contributes to the quantity regulation of these four metabolites depends on whether NNMT is a major consumer or producer of these metabolites, which varies among various cellular contexts. Yet, whether NNMT critically regulates these metabolites in the AML12 hepatocyte cell line has been unexplored. To address this, we knock down Nnmt in AML12 cells and investigate the effects of Nnmt RNAi on metabolism and gene expression. We find that Nnmt RNAi accumulates SAM and SAH, whereas it reduces MNAM with NAM being unaltered. These results indicate that NNMT is a significant consumer of SAM and critical for MNAM production in this cell line. Moreover, transcriptome analyses reveal that altered SAM and MNAM homeostasis is accompanied by various detrimental molecular phenotypes, as exemplified by the down-regulations of lipogenic genes such as Srebf1. Consistent with this, oil-red O-staining experiments demonstrate the decrease of total lipids upon Nnmt RNAi. These results suggest that NNMT maintains proper SAM and MNAM homeostasis, providing an additional example where NNMT plays a critical role in regulating SAM and MNAM metabolism.

biochemistry↗

bioRxiv2017

A novel zebrafish intestinal tumor model reveals a role for cyp7a1-dependent tumor-liver crosstalk in tumor's adverse effects on host

The nature of host organs and genes that underlie tumor-induced physiological disruption on host remains ill-defined. Here, we establish a novel zebrafish intestinal tumor model that is optimized for addressing this issue, and find that hepatic cyp7a1, the rate-limiting factor for synthesizing bile acids (BAs), is such a host gene. Inducing krasG12D by Gal4 specifically expressed in the posterior intestine resulted in formation of an intestinal tumor classified as dysplasia. The local intestinal tumor caused systemic detrimental effects on host including liver inflammation, hepatomegaly, growth defects, and organismal death. Whole-organismal level gene expression analysis and metabolite measurements revealed that the intestinal tumor reduced total BAs levels via down-regulation of hepatic cyp7a1. Genetically rescuing cyp7a1 expression in the liver restored the BAs synthesis and ameliorated tumor-induced liver inflammation, but not other tumor-dependent phenotypes. Thus, we found a previously unknown role of cyp7a1 as the host gene that links the intestinal tumor, hepatic cholesterol-BAs metabolism, and liver inflammation in tumor-bearing fish. Our model provides an important basis to discover host genes responsible for tumor-induced phenotypes and to uncover mechanisms underlying how tumors adversely affect host organisms.

cancer biology↗