Biology subjects

Rayes, J.

Publications and source records attributed to Rayes, J..

7 recordsLinked to original sources

bioRxiv2026

Galectin-9 drives thrombo-inflammatory circuits initiating venous thrombosis

Background: Venous thromboembolism is increasingly recognized as a thrombo-inflammatory disease, yet the pathways linking inflammation to venous thrombus initiation remain incompletely defined. Galectin-9 (Gal-9), a {beta}-galactoside-binding lectin elevated in inflammatory disorders, has no defined role in venous thrombosis. Methods: Using plasma from patients with deep vein thrombosis (DVT), Gal-9-deficient mice, an inferior vena cava stenosis model, intravital microscopy, microfluidics, and ex vivo platelet and neutrophil assays, we assessed the functional contribution of Gal-9 to venous thrombosis. Results: Plasma Gal-9 was elevated in DVT patients, correlated with D-dimer at presentation, and declined over 3-month follow-up. Gal-9 deletion did not alter hemostasis but markedly impaired thrombus initiation, with reduced platelet and neutrophil recruitment to the vessel wall and reduced intra-thrombus neutrophil extracellular trap (NET) formation. TNF-/IFN-{gamma}-stimulated endothelial cells upregulated Gal-9 and promoted platelet adhesion and fibrin(ogen) deposition, which Gal-9 neutralization partially reversed. Under venous shear, immobilized recombinant Gal-9 potentiated platelet activation and thrombus formation, particularly alongside collagen, whereas Gal-9 inhibition suppressed these responses. Gal-9-activated platelets promoted NETosis and shifted thrombus composition toward a NET-rich inflammatory phenotype. Conclusions: Gal-9 is a previously unrecognized driver of venous thrombo-inflammation, linking vascular inflammation to platelet activation, NET formation, and thrombosis. Genetic deletion attenuated these responses in vivo, and antibody-mediated Gal-9 neutralization suppressed platelet activation and thrombus formation in vitro, identifying the Gal-9 glycan-binding pathway as a therapeutic target that disrupts thrombosis without impairing hemostasis.

immunology↗

bioRxiv2025

Neutrophil and NET-driven pulmonary microvascular injury following myocardial injury: attenuation by S100A8/A9 inhibition

Myocardial infarction (MI) triggers not only local cardiac damage but also a systemic inflammatory response that extends to remote organs. The pulmonary microcirculation, by virtue of its dense capillary network and direct anatomical proximity to the heart, is particularly vulnerable. Neutrophils and their effector mechanisms, including neutrophil extracellular traps (NETs) and the alarmin S100A8/A9, have been implicated in adverse cardiovascular outcomes. However, their role in remote damage post-MI remains unclear. Using intravital in vivo imaging in murine MI models and analysis of human lung tissues, we show that MI induces rapid pulmonary neutrophil and platelet recruitment, formation of platelet-neutrophil aggregates within capillaries, and endothelial activation. These changes are accompanied by NET release, fibrin deposition, and microvascular obstruction, leading to impaired vascular perfusion and necrosis. These pulmonary disturbances closely parallel those in the infarcted myocardium and exceed responses observed in other organs such as the kidney and liver, highlighting the lung as a vulnerable target organ. Increased neutrophil recruitment was associated with marked upregulation of the neutrophil-derived, NET-associated alarmin S100A8/A9 in mouse and human lungs, where it co-localised with infiltrating neutrophils, NETs, and platelet aggregates. Additionally, we show that short-term pharmacological inhibition of S100A8/A9 with ABR-238901 significantly attenuated pulmonary neutrophil infiltration, reduced NETosis and fibrin deposition, and restored capillary perfusion while rebalancing the pulmonary immune landscape. Together, these findings identify the lung as a principal site of remote thrombo-inflammatory injury after MI and implicate S100A8/A9, a neutrophil-derived, NET-associated alarmin, as a mechanistic driver of pulmonary microvascular dysfunction. We propose that targeting this pathway could provide dual protection for both cardiac and pulmonary microcirculations in the acute phase of myocardial injury. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=129 SRC="FIGDIR/small/675647v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@289725org.highwire.dtl.DTLVardef@db2011org.highwire.dtl.DTLVardef@16790dorg.highwire.dtl.DTLVardef@1655b17_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2025

comBO: A combined human bone and lympho-myeloid bone marrow organoid for pre-clinical modelling of haematopoietic disorders

The bone marrow supports lifelong blood and immune cell production. Current human bone marrow organoid models do not include both lymphoid and myeloid elements and lack the complexity of stromal cell types present in native haematopoietic tissues, precluding the accurate ex vivo modelling of human pathologies. Here we introduce "comBOs" (combined bone and lympho-myeloid bone marrow organoids) that include osteolineage, vascular, lymphoid and myeloid cells. comBOs are generated by the differentiation of induced pluripotent stem cells guided by physiologically-relevant oxygen and cytokine exposures within an innovative granular microgel scaffold to increase scalability and reproducibility. We demonstrate that comBOs can be used to generate "chimeroids" - incorporating healthy or aberrant cells from adult donors - and recapitulate features of diseased microenvironments. ComBOs are one of the most physiologically-relevant human organoid systems to date, and this study showcases the potential of 3D in vitro disease models for discovery science and translational studies.

cancer biology↗

bioRxiv2024

Spleen tyrosine kinase inhibition mitigates hemin-induced thromboinflammation in the lung and kidney of sickle cell mice

Sickle cell disease (SCD) leads to hemolytic anemia, vaso-occlusive crisis (VOC), hypoperfusion, and progressive organ damage. Hemin, released during hemolysis in SCD, induces platelet activation through CLEC-2, endothelial activation through TLR4, neutrophil adhesion and NETosis, all of which are regulated by spleen tyrosine kinase (Syk). In this study, we assessed neutrophil and platelet recruitment to the pulmonary, renal, splenic, and hepatic microvasculature in control and SCD mice following hemin injection and the effect of Syk inhibition on cell recruitment and organ perfusion. Compared to controls, SCD mice exhibited higher baseline neutrophil and platelet recruitment to the lungs without alterations in lung perfusion as measured by laser speckle contrast imaging. Injection of hemin increased cell recruitment to the pulmonary and renal vasculature with a concomitant reduction in organ perfusion. However, hemin injection did not change cell recruitment or organ perfusion in the spleen and liver, both of which were altered at baseline in SCD mice. Pretreatment of SCD mice with the Syk inhibitor BI-1002494 mitigated baseline and hemin-induced neutrophil and platelet adhesion in the pulmonary and renal microvasculature, with a corresponding normalization of perfusion. Syk regulates vascular integrity in the lung of SCD mice; whilst high concentrations of BI-1002494 increased bleeding, lowering drug concentrations preserved the inhibitory effect on platelet and neutrophil recruitment and lung perfusion and protected from bleeding complications. These data substantiate Syk as a mediator of vascular thrombo-inflammation and hypoperfusion in the lung and kidney of SCD and provide a rationale for pharmacological inhibition as a therapeutic strategy.

pathology↗

bioRxiv2024

Discrete and conserved inflammatory signatures drive thrombosis in different organs after Salmonella infection

Inflammation-induced thrombosis is a common consequence of bacterial and viral infections, such as those caused by Salmonella Typhimurium (STm) and SARS-CoV-2. The identification of multi-organ thrombosis and the chronological differences in its induction and resolution raises significant challenges for successfully targeting multi-organ infection-associated thrombosis. Here, we identified specific pathways and effector cells driving thrombosis in the spleen and liver following STm infection. Thrombosis in the spleen is independent of IFN-{gamma} or the platelet C-type lectin-like receptor CLEC-2, while both molecules were previously identified as key drivers of thrombosis in the liver. Furthermore, we identified platelets, monocytes, and neutrophils as core constituents of thrombi in both organs. Depleting neutrophils or monocytic cells independently abrogated thrombus formation. Nevertheless, blocking TNF, which is expressed by both myeloid cell types, diminished both thrombosis and inflammation which correlates with reduced endothelial expression of E-selectin and leukocyte infiltration. Moreover, tissue factor and P-selectin glycoprotein ligand 1 inhibition impair thrombosis in both spleen and liver, identifying multiple common checkpoints to target multi-organ thrombosis. Therefore, organ-specific, and broad mechanisms driving thrombosis potentially allow tailored treatments based on the clinical need and to define the most adequate strategy to target both thrombosis and inflammation associated with systemic infections.

immunology↗

bioRxiv2022

Human bone marrow organoids for disease modelling, discovery and validation of therapeutic targets in hematological malignancies

A lack of models that recapitulate the complexity of human bone marrow has hampered mechanistic studies of normal and malignant hematopoiesis and the validation of novel therapies. Here, we describe a step-wise, directed-differentiation protocol in which organoids are generated from iPSCs committed to mesenchymal, endothelial and hematopoietic lineages. These 3-dimensional structures capture key features of human bone marrow - stroma, lumen-forming sinusoidal vessels and myeloid cells including pro-platelet forming megakaryocytes. The organoids supported the engraftment and survival of cells from patients with blood malignancies, including cancer types notoriously difficult to maintain ex vivo. Fibrosis of the organoid occurred following TGF{beta} stimulation and engraftment with myelofibrosis but not healthy donor-derived cells, validating this platform as a powerful tool for studies of malignant cells and their interactions within a human bone marrow-like milieu. This enabling technology is likely to accelerate discovery and prioritization of novel targets for bone marrow disorders and blood cancers. Significance StatementWe present a 3D, vascularised human bone marrow organoid that supports growth of primary cells from patients with myeloid and lymphoid blood cancers. This model allows for mechanistic studies of blood cancers in the context of their microenvironment, and provides a much-needed, ex vivo tool for prioritization of new therapeutics.

cancer biology↗

bioRxiv2020

CLEC-2 promotes inflammatory peritoneal macrophage emigration to draining lymph nodes during endotoxemia

Macrophage recruitment during sterile inflammation and infection is essential to clear pathogens, apoptotic cells and debris. However, persistent macrophage accumulation leads to chronic inflammation. Platelets are emerging as key modulators of the inflammatory response. Here, we identify that platelet C-type-lectin-like receptor-2 (CLEC-2) is a crucial immunomodulatory receptor through the interaction with podoplanin, upregulated on inflammatory macrophages. Mechanistically, platelet CLEC-2 upregulates the expression of podoplanin and its co-ligands CD44 and ERM proteins, leading to actin rearrangement and promotion of cell migration; this is mimicked by recombinant CLEC-2-Fc (rCLEC-2-Fc). Treatment of LPS-challenged mice with rCLEC-2-Fc induces a rapid emigration of peritoneal macrophages to mesenteric lymph nodes, through a gradient generated by the podoplanin ligand, CCL21, to prime T cells. We propose that crosslinking podoplanin using rCLEC-2-Fc is a novel, cell-specific strategy to accelerate macrophage removal from the site of inflammation, and hence promote the resolution of the inflammatory response. Visual Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=188 SRC="FIGDIR/small/423770v1_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@e37acborg.highwire.dtl.DTLVardef@92a5e1org.highwire.dtl.DTLVardef@1c8832eorg.highwire.dtl.DTLVardef@11c5c97_HPS_FORMAT_FIGEXP M_FIG C_FIG SummaryPersistent macrophage accumulation in inflamed tissue leads to chronic inflammation and organ damage. Bourne et al. identify recombinant CLEC-2-Fc crosslinking podoplanin on inflammatory macrophages, as a cell-specific strategy to accelerate their emigration to draining lymph nodes, and reduce local inflammation.

immunology↗