Biology subjects

Morooka, N.

Publications and source records attributed to Morooka, N..

3 recordsLinked to original sources

bioRxiv2024

Microthrombi-growth in ADAMTS13 deficiency exacerbated ulcerative colitis via mucosal and endothelial dysfunction

BackgroundUlcerative colitis (UC) is a chronic inflammatory bowel disease characterized by mucosal inflammation and ulceration, with systemic immune dysregulation exacerbating disease progression. While the accumulation of von Willebrand factor (VWF), normally digested by a disintegrin-like and metalloproteinase with thrombospondin type 1 motif 13 (ADAMTS13) from ultra-large multimers to small molecules, has been implicated in UC pathogenesis, the association between aberrant microthrombus formation and colitis remains unclear. MethodsPlasma and inflamed colonic tissues from UC patients were analyzed. In the experimental colitis model, we employed an intravital imaging technique to reveal real-time structural dynamics of the mucus layer and the mucosal vasculature. Dextran sulfate sodium (DSS)-induced colitis in wild-type and ADAMTS13-deficient mice was evaluated for disease progression, mucus layer disruption, leukocyte recruitment, and thrombus formation in mucosal vessels using intravital multiphoton excitation microscopy within single-cell spatial resolution. ResultsUC patients exhibited significantly reduced plasma ADAMTS13 activity correlating with disease severity and excessive VWF deposition in inflamed colonic tissues. In DSS-induced colitis mice, ADAMTS13 deficiency showed heightened disease activity and increased mucosal erosion in histochemical analysis compared to wild-type mice. A novel methodology established in this study using intravital microscopy successfully appraised colonic mucus barrier integrity by visualizing fluorescent dextran penetration from the colonic lumen to the crypts. ADAMTS13 deficiency accelerated mucus layer disruption, leukocyte adhesion, and microthrombi formation, particularly close to crypt epithelium regions. Vessel-specific analyses demonstrated that obstructive microthrombi were most prominent in the mucosal layer, contributing to local ischemia and mucosal erosion. Therapeutical usage of recombinant human ADAMTS13 alleviated microthrombus formation, improved mucosal integrity, and mitigated colitis severity in wild-type and ADAMTS13-deficient mice. ConclusionsObstructive thrombi formed in mucosal vessels due to impaired ADAMTS13 activity appeared essential in the disease progression of UC. Advanced intravital imaging provided novel insights into single-cell resolution UC pathogenesis.

physiology↗

bioRxiv2024

An in vitro modelling of resolving macrophage with Raw 264.7 macrophage cell line

In acute inflammation, macrophages polarises its phenotype in order to participate effectively in the inflammatory, anti-inflammatory and resolving phases. Particularly, the resolving phase is vital for homeostatic recovery. The in vivo murine peritonitis model had identified various subtypes of resolving macrophages. However, the in vivo model has limitations in deciphering the molecular mechanisms required for resolving macrophage polarisation. Therefore the aim of this study is to establish an in vitro model that could simplify the reproduction of resolving macrophage polarisation. This model will be a useful tool to screen for molecular mechanisms essential for triggering resolution. Our in vitro model showed Raw 264.7 cells exhibited classical inflammatory-like (M1-like) phenotype between 2-24 h with increased interleukin-1{beta} expression and tumour necrosis factor- secretion. Concurrently, at 22-24 h there was an increase in Raw 264.7 cells polarising to anti-inflammatory like (M2-like) phenotype. These M2-like macrophages were increased in arginase activity and interleukin-10 expression. By 48 h, Raw 264.7 cells were polarised to resolving-like (Mres-like/CD11blow) phenotype. These macrophages were characterised by high efferocytic index and a decrease in inflammatory cytokine expression, low arginase activity and low CD11b expression. In summary, this in vitro resolution model showed resolving-like polarisation in a macrophage cell line.

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↗