Biology subjects

Kawaguchi, H.

Publications and source records attributed to Kawaguchi, H..

6 recordsLinked to original sources

bioRxiv2026

Applying Spatial Statistics to Spatial Transcriptomics Reveals Local Association Between M2-like Macrophages and Fibrosis in Diabetic Kidney Disease

Renal fibrosis is the common final pathway of chronic kidney disease (CKD), driven in part by myofibroblast-mediated extracellular matrix deposition. M2 macrophages, hereafter referred to as MAC-M2, have been implicated in renal fibrosis, yet whether M2 macrophages are pro- or anti-fibrotic remains controversial, and the spatial context in which MAC-M2-fibrosis coupling occurs is unknown. Here, we applied geographically weighted regression (GWR), a spatial statistical method, to Visium spatial transcriptomics data from diabetic kidney disease (DKD) to characterize spatially resolved high-coupling spots where MAC-M2-fibrosis coupling is significantly positive. In a small DKD cohort (n=6), GWR identified high-coupling spots enriched for B cell and tertiary lymphoid structure (TLS)-like immune signatures, suggesting that the GWR-defined regions captured biologically meaningful immune microenvironments. To gain statistical power for differential gene expression (DEG) analysis, we then applied the same pipeline to the larger Kidney Precision Medicine Project (KPMP) DKD cohort (n=30), in which high-coupling spots showed upregulation of IgE-related immune genes (IGHE, FCER1A) together with the mast cell tryptase TPSB2. These findings suggest that IgE-related immune responses may be present within DKD fibrotic microenvironments characterized by local MAC-M2-fibrosis coupling. As a disease comparison, we further applied the pipeline to a KPMP hypertensive kidney disease (HKD) cohort (n = 27), where high-coupling spot signatures were distinct from DKD and did not show enrichment of IgE-related genes. Together, this study provides the first application of GWR to kidney spatial transcriptomics and suggests that IgE-related immune responses may be a feature of DKD fibrotic microenvironments in which M2 macrophages are locally associated with fibrosis. HighlightsO_LIGeographically weighted regression (GWR) maps spatially variable M2 macrophage-fibrosis coupling in diabetic kidney disease (DKD). C_LIO_LIGWR-defined high-coupling spots show immune activation and loss of kidney-specific programs. C_LIO_LIThe GWR-based analysis was replicated across two independent DKD cohorts. C_LIO_LIIGHE, FCER1A, and the mast cell marker TPSB2 are enriched in high-coupling spots in the KPMP DKD cohort. C_LI

bioinformatics↗

bioRxiv2023

Stress granule dysfunction via chromophore-associated light inactivation

Stress granules (SGs) are cytoplasmic condensates composed of various proteins and RNAs that protect translation-associated machinery from harmful conditions during stress. However, the method of spatio-temporal inactivation of condensates such as SGs in live cells to study cellular phenotypes is still in the process of being demonstrated. Here, we show that the inactivation of SG by chromophore-associated light inactivation (CALI) using a genetically encoded red fluorescence protein (SuperNova-Red) as a photosensitizer leads to differences in cell viability during recovery from hyperosmotic stress. CALI delayed the disassembly kinetics of SGs during recovery from hyperosmotic stress. Consequently, CALI could inactivate the SGs, and the cellular fate due to SGs could be analyzed. Furthermore, CALI is an effective spatiotemporal knockdown method for intracellular condensates/aggregates and would contribute to the elucidation of importance of such condensates/aggregates.

biophysics↗

bioRxiv2022

Increased intracellular crowding during hyperosmotic stress

Hyperosmotic stress activates in live cells numerous processes and also promotes intracellular protein/RNA aggregation and phase separation. However, the time course and the extent of these changes remain largely uncharacterized. To investigate dynamic changes in intracellular macromolecular crowding (MMC) induced by hyperosmotic stress in live cells, we used Fluorescence Lifetime Imaging Microscopy (FLIM) and Fluorescence Correlation Spectroscopy (FCS) to quantify changes in the local environment by measuring the fluorescence lifetime and the diffusion of the monomeric enhanced Green Fluorescent Protein (eGFP), respectively. Real-time monitoring of eGFP fluorescence lifetime showed that a faster response to environmental changes due to MMC is observed than when measuring the acceptor/donor emission ratio using the MMC-sensitive Forster Resonance Energy Transfer sensor (GimRET). This suggests that eGFP molecular electronic states and/or collision frequency are affected by changes in the immediate surroundings due to MMC without requiring conformational changes as is the case for the GimRET sensor. Furthermore, eGFP diffusion assessed by FCS indicated higher intracellular viscosity due to increased MMC during hyperosmotic stress. Our findings reveal that changes in eGFP fluorescence lifetime and diffusion are early indicators of elevated intracellular MMC. These variables can therefore be used for quantitative characterization of MMC in live cells.

biophysics↗

bioRxiv2019

Cerebral artery segmentation based on magnetization-prepared two rapid acquisition gradient echo multi-contrast images in 7 Tesla magnetic resonance imaging

Cerebral artery segmentation plays an important role in the direct visualization of the human brain to obtain vascular system information. At ultra-high field magnetic resonance imaging, hyperintensity of the cerebral arteries in T1 weighted (T1w) images could be segmented from brain tissues such as gray and white matter. In this study, we propose an automated method to segment the cerebral arteries using multi-contrast images including T1w images of a magnetization-prepared two rapid acquisition gradient echoes (MP2RAGE) sequence at 7 T. The proposed method employed a seed-based region-growing strategy with the following procedures. (1) Two seed regions were defined by Frangi filtering applied to T1w images and by a simple calculation from multi-contrast images, (2) the two seed regions were combined, (3) the combined seed regions were expanded using a region growing algorithm to acquire the cerebral arteries. Time-of-flight (TOF) images were obtained as a reference to evaluate the proposed method. We successfully performed vessel segmentations from T1w MP2RAGE images, which mostly overlapped with the segmentations from the TOF images. As large arteries can affect the normalization of anatomical images to the standard coordinate space in functional and structural studies, we also investigated the effect of the cerebral arteries on spatial transformation using vessel segmentation by the proposed method. As a result, the T1w image removing the cerebral arteries showed better agreement with the standard atlas compared with the T1w image containing the arteries. Thus, because the proposed method using MP2RAGE images can obtain brain tissue anatomical information as well as cerebral artery information without need for additional acquisitions such as of the TOF sequence, it is useful and time saving for medical diagnosis and functional and structural studies.

neuroscience↗

bioRxiv2019

Acute feeding disorder after oral RNAi exposure results in efficient pest control

Selecting an appropriate target gene is critical to the success of feeding RNA interference (f-RNAi)-based pest control. Gene targets have been chosen based on their ability to induce lethality. However, lethality induction by f-RNAi is slow-acting and crop damage can progress during this time. Here, we show that f-RNAi of death-associated inhibitor of apoptosis protein 1 (diap1), but not two conventional targets vacuolar ATPase subunit A and E, induces acute feeding cessation in the solanaceous pest, Henosepilachna vigintioctopunctata during 24-48 hours. We also found that the feeding cessation by diap1 f-RNAi has species-specificity and occurs with only 1.6 ng dsRNA. Our results suggest that diap1 is an appropriate target in the context of rapid reduction of crop damage. We propose that acute feeding disorder should be assessed as a novel criterion for selecting appropriate target genes for RNAi-based pest control in addition to the conventional criterion based on lethality.

molecular biology↗

bioRxiv2018

Brain tissue segmentation based on MP2RAGE multi-contrast images in 7 T MRI

We proposed a method for segmentation of brain tissues--gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF)--using multi-contrast images, including a T1 map and a uniform T1-weighted image, from a magnetization-prepared 2 rapid acquisition gradient echoes (MP2RAGE) sequence at 7 Tesla. The proposed method was evaluated with respect to the processing time and the similarity of the segmented masks of brain tissues with those obtained using FreeSurfer, FSL, and SPM12. The processing time of the proposed method (28 {+/-} 0 s) was significantly shorter than those of FSL and SPM12 (444 {+/-} 4 s and 159 {+/-} 2 s for FSL and SPM12, respectively). In the similarity assessment, the tissue mask of the brain obtained by the proposed method showed higher consistency with those obtained by FSL than with those obtained by SPM12. The proposed method misclassified the subcortical structures and large vessels since it is based on the intensities of multi-contrast images obtained using MP2RAGE, which uses a similar segmentation approach as FSL but is not based on a template image or a parcellated brain atlas, which are used for FreeSurfer and SPM12, respectively. However, the proposed method showed good segmentation in the cerebellum and WM in the medial part of the brain in comparison with the other methods. Thus, because the proposed method using different contrast images of MP2RAGE sequence showed the shortest processing time and similar segmentation ability as the other methods, it may be useful for both neuroimaging research and clinical diagnosis.

neuroscience↗