Biology subjects

Fukumoto, M.

Publications and source records attributed to Fukumoto, M..

4 recordsLinked to original sources

bioRxiv2025

Endothelial-zippering proceeds by sensing heartbeat-driven force through Cadherin-6 during heart-vessel connection in zebrafish

The connection between the heart and great vessels established during embryogenesis is essential for circulation. However, how great veins adhere to the endocardium lining the inside lumen of the beating heart remains unknown. Here, using zebrafish, we demonstrate that the endocardium and great veins are sealed in a zipper-closing manner outside the beating heart. The gradual elongation of the endocardium, driven by convergent extension, organized this adhesion by pulling venous ECs along the anterior-posterior axis. Time-specific manipulation of the heart rate revealed that this endocardial elongation proceeds against heartbeat-driven force. From time-lapse imaging of adherens junctions, which would counterbalance mechanical forces, we found a specific contribution of Cadherin-6 instead of Cadherin-5 in sensing endocardium-specific mechanical force. This specificity was confirmed by the depletion of Cadherin-6 that caused endocardium deformation. Altogether, we propose Cadherin-6 mediated EC-zippering as a novel mechanism that updates the understanding of Cadherin usage in dynamic morphogenesis.

developmental biology↗

bioRxiv2025

Chemokine induces phase transition from non-directional to directional migration during angiogenesis

During angiogenesis, sprouting endothelial cells (ECs) migrate and eventually connect to target vessels to form new vessel branches. However, it remains unclear how these sprouting vessels migrate toward the target vessels in three-dimensional space. We performed in vivo imaging of the cerebral capillary network formation in zebrafish to investigate how sprouting tip cells migrate toward their targets. Of note, we found that tip cells reach the target vessels through two phases: a non-directional phase and a directional phase. In the non-directional phase, sprouting tip cells dynamically extend and retract their protrusions at the leading front and have less directionality in their movement. In contrast, once tip cells enter the directional phase, they migrate directly toward the anastomotic targets. Chemokine receptor Cxcr4a and its ligand Cxcl12b are important for the phase transition to the directional phase. In cxcr4a mutants, sprouting tip cells lose their directionality and tend to connect to nearby sprouting ECs, resulting in altered capillary network patterning. Furthermore, in wild-type (WT) larvae, local Ca2+ oscillations were detected in protrusions of tip cells, specifically in the non-directional phase, but almost disappeared in the directional phase as a result of the Cxcr4-dependent phase transition. Thus, this study provides evidence of a chemokine-induced phase transition in migrating tip cells, which is important for proper vascular network formation in the zebrafish brain.

cell biology↗

bioRxiv2023

Angpt1 binding to Tie1 regulates the signaling required for lymphatic vessel development in zebrafish

Development of the vascular system is regulated by multiple signaling pathways mediated by receptor tyrosine kinases (RTKs). Among them, Angiopoietin (Ang)/Tie signaling regulates lymphatic and blood vessel development in mammals. Of the two Tie receptors, Tie2 is well known as a key mediator of Ang/Tie signaling, but unexpectedly, recent studies reveal that the Tie2 locus has been lost in many vertebrate species, while the Tie1 gene is more commonly present. However, Tie1-driven signaling pathways, including ligands and cellular functions, are not well understood. Here, we performed comprehensive mutant analyses of Angiopoietins and Tie receptors in zebrafish and found that only angpt1 and tie1 mutants show defects in trunk lymphatic vessel development. Among zebrafish Angiopoietins, only Angpt1 binds to Tie1 as a ligand. We indirectly monitored Ang1/Tie1 signaling and detected Tie1 activation in sprouting endothelial cells (ECs), where Tie1 inhibits nuclear import of EGFP-Foxo1a. Angpt1/Tie1 signaling functions in EC migration, proliferation, and lymphatic specification during early lymphangiogenesis, at least in part by modulating Vegfc/Vegfr3 signaling. Thus, we show Angpt1/Tie1 signaling to constitute an essential signaling pathway for lymphatic development in zebrafish. Brief Summary StatementZebrafish Angpt1/Tie1 signaling is characterized as an essential signaling pathway for trunk lymphatic development, with Tie1 regulating Foxo1 localization and modulating Vegfc/Vegfr3 signaling.

developmental biology↗

bioRxiv2019

Automated acquisition of knowledge beyond pathologists

Deep learning algorithms have been successfully used in medical image classification and cancer detection. In the next stage, the technology of acquiring explainable knowledge from medical images is highly desired. Herein, fully automated acquisition of explainable features from annotation-free histopathological images is achieved via revealing statistical distortions in datasets by introducing the way of pathologists examination into a set of deep neural networks. As validation, we compared the prediction accuracy of prostate cancer recurrence using our algorithm-generated features with that of diagnosis by an expert pathologist using established criteria on 13,188 whole-mount pathology images. Our method found not only the findings established by humans but also features that have not been recognized so far, and showed higher accuracy than human in prognostic prediction. This study provides a new field to the deep learning approach as a novel tool for discovering uncharted knowledge, leading to effective treatments and drug discovery.

bioinformatics↗