Biology subjects

Navarro, S.

Publications and source records attributed to Navarro, S..

8 recordsLinked to original sources

bioRxiv2025

Targeting platelet GPVI or GPIIb/IIIa only minimally affect acute inflammation and cardiac repair in experimental permanent myocardial infarction

BackgroundBeyond their role in hemostasis, platelets are recognized as key regulators of inflammatory responses in ischemic diseases, including cardiac ischemia/reperfusion (I/R) injury with key roles of platelet membrane glycoproteins (GP)VI and IIb/IIIa. However, whether platelet-driven thrombo-inflammatory pathways affect acute inflammation and cardiac repair processes in permanent, non-reperfused myocardial infarction (MI) is unknown. MethodsWe targeted GPVI and GPIIb/IIIa in experimental permanent MI in mice. Cardiac, bone marrow, and blood innate immune responses were evaluated by flow cytometry and single-cell RNA-sequencing. Survival and cardiac repair were assessed over the inflammatory and scar formation phase, until day 10 after permanent MI. ResultsPlatelet GPVI immunodepletion by injection of the anti-GPVI antibody JAQ1 did not affect levels of neutrophil or monocyte subsets (Ly6Chi and Ly6Clow) in the bone marrow and blood, and did not alter accumulation of monocytes, macrophage subsets (defined by expression of MHCII and TIM4), or neutrophil subsets (SiglecFhi/low) in the infarcted heart on day 4. GPVI depletion only had a minimal effect on cardiac repair, slightly decreasing interstitial fibrosis in the infarct border zone on day 10. Four days after MI, GPIIb/IIIa inhibition by JON/A-F(ab')2 had no effect on cardiac or systemic innate immune cell levels as measured by flow cytometry and did not affect composition and transcriptomic profile of the cardiac immune infiltrate as revealed by single-cell RNA-sequencing. GPIIb/IIIa inhibition did not improve cardiac remodeling, and was even associated with an increased mortality rate over 10 days post-MI. ConclusionTargeting the GPVI-GPIIb/IIIa axis only had minor effects on post-MI inflammatory responses and cardiac wound healing in permanent myocardial ischemia. Our findings demonstrate that the therapeutic benefits of inhibiting platelet-driven thrombo-inflammation are particularly relevant in the subacute reperfusion phase.

physiology↗

bioRxiv2025

DANEELpath: Open-source Digital analysis tools for histopathological research. Applications in NEuroblastoma modELs

Despite the considerable expansion of bioimage analysis as a subfield of biomedical sciences, there is an ongoing need for comprehensive image analysis pipelines to address specific biological inquiries. In the tumor microenvironment, the extracellular matrix (ECM) plays a pivotal role in cancer progression, promoting tumor cell adaptability, intratumor heterogeneity, and therapeutic resistance. In neuroblastoma (NB), the ECM glycoprotein vitronectin (VN) has been associated with more aggressive tumors. Three-dimensional (3D) hydrogels are an emerging biomimetic tool with significant potential for studying the role of ECM elements and testing new mechano-drugs such as cilengitide (CLG), a potential therapeutic agent to treat high-risk (HR) NB due to its ability to inhibit VN activity in cells. To gain a more detailed understanding of the effects of VN and CLG in 3D-grown NB cells, we developed DANEELpath, an open-source image analysis toolkit. DANEELpath integrates deep learning techniques, specific segmentation of individual and cluster cells through mathematical morphology pipelines, and extraction of spatial features within whole-slide images. Thanks to its versatility, DANEELpath is adaptable to address different biological questions and has significant potential for use in a variety of research fields and model systems, which could help advance biomedical discovery.

cancer biology↗

bioRxiv2025

Cracking the egg: Isolation and discovery of distinct nonvesicular extracellular particles from Schistosoma mansoni eggs

Extracellular particles (EPs) derived from helminths are emerging as promising immunomodulatory agents, yet their heterogeneity challenges reproducible purification and characterisation. This study focused on purifying and characterising extracellular particles (EPs) from Schistosoma mansoni eggs using tangential flow filtration (TFF) and differential ultracentrifugation (dUC). Contrary to expectations, cryogenic transmission electron microscopy (cryoTEM) revealed that egg-derived EPs are nonvesicular (5-30 nm) nanoparticles (eggNPs) rather than membrane-bound extracellular vesicles. TFF demonstrated superior performance over dUC, yielding higher recovery (76.19% vs. 38.90%), greater purity, and lower endotoxin contamination. Despite limitations in standard protein quantification methods, enriched protein profiles and detection of S. mansoni tetraspanin-2 in TFF-purified eggNPs highlights their distinct molecular signatures. The study also identified contaminants in cryopreservation buffers, underscoring the need for optimised storage conditions. Compared to dUC, TFF preserved particle integrity, with cryoTEM images showing fewer aggregates and distinct EggNP morphology. This work proposes TFF as a scalable and reproducible method for isolating S. mansoni-derived eggNPs, providing a foundation for their exploration as immunomodulatory agents. These findings not only expand the understanding of helminth EPs but also emphasise their therapeutic potential, particularly in inflammatory and immune-dysregulation disorders.

molecular biology↗

bioRxiv2025

Inhibition of NLRP1 Inflammasome Activation by Tyrosine Kinase Inhibitors Restores Erythropoiesis in Diamond-Blackfan Anemia Syndrome

Diamond-Blackfan Anemia Syndrome (DBAS) is characterized by impaired erythropoiesis due to dysfunctional ribosome biogenesis and aberrant cellular signaling. Here, we investigate how ribosomal stress-induced activation of the NLRP1 inflammasome modulates erythroid differentiation in DBAS. We demonstrate that FDA/EMA-approved tyrosine kinase inhibitors (TKIs) effectively mitigate defective erythropoiesis in Diamond-Blackfan anemia syndrome (DBAS) by inhibiting NLRP1 inflammasome activation. Specifically, nilotinib enhances erythroid differentiation in K562 cells through suppression of the ZAK/P38/NLRP1/CASP1 axis, leading to increased GATA1 protein levels and upregulation of key erythroid genes involved in iron acquisition, hemoglobin synthesis, and erythrocyte structure. These effects were validated in human CD34+ hematopoietic stem and progenitor cells (HSPCs) and zebrafish models, where nilotinib, along with other TKIs (imatinib, dasatinib, and bosutinib), promoted erythropoiesis at the expense of myelopoiesis and reduced caspase-1 activity. Importantly, in RPS19-deficient zebrafish and human models and HSPCs from patients with DBAS, nilotinib, imatinib and dasatinib rescued defective erythroid differentiation and restored hemoglobin levels. These findings highlight the potential of TKIs to address the erythroid defects observed in ribosomopathies like DBAS. Given the limited treatment options available for DBAS and other congenital anemias, our study provides compelling evidence for repurposing TKIs as a novel therapeutic strategy to alleviate pathological NLRP1 activation and improve erythropoiesis. This work opens new avenues for managing ribosome-related disorders and advancing personalized medicine approaches for hematopoietic diseases.

immunology↗

bioRxiv2023

Quantitative Assessment of Morphological Changes in Lipid Droplets and Lipid-Mito Interactions with Aging in Brown Adipose

The physical characteristics of brown adipose tissue (BAT) are defined by the presence of multilocular lipid droplets (LD) within the brown adipocytes and a high abundance of iron-containing mitochondria, which give it its characteristic color. Normal mitochondrial function is, in part, regulated by organelle-to-organelle contacts. Particularly, the contact sites that mediate mitochondria-LD interactions are thought to have various physiological roles, such as the synthesis and metabolism of lipids. Aging is associated with mitochondrial dysfunction, and previous studies show that there are changes in mitochondrial structure and proteins that modulate organelle contact sites. However, how mitochondria-LD interactions change with aging has yet to be fully clarified. Therefore, we sought to define age-related changes in LD morphology and mitochondria-lipid interactions in BAT. We examined the three-dimensional morphology of mitochondria and LDs in young (3-month) and aged (2-year) murine BAT using serial block face-scanning electron microscopy and the Amira program for segmentation, analysis, and quantification. Analysis showed reductions in LD volume, area, and perimeter in aged samples compared to young samples. Additionally, we observed changes in LD appearance and type in aged samples compared to young samples. Notably, we found differences in mitochondrial interactions with LDs, which could implicate that these contacts may be important for energetics in aging. Upon further investigation, we also found changes in mitochondrial and cristae structure for mitochondria interacting with LD lipids. Overall, these data define the nature of LD morphology and organelle-organelle contacts during aging and provide insight into LD contact site changes that interconnect biogerontology and mitochondrial functionality, metabolism, and bioactivity in aged BAT. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=141 SRC="FIGDIR/small/559135v2_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@e5b7org.highwire.dtl.DTLVardef@e965e5org.highwire.dtl.DTLVardef@120c7e9org.highwire.dtl.DTLVardef@124bfb5_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract Workflow highlighting the process of murine interscapular BAT extraction, processing and imaging serial block facing-scanning electron microscopy and using Amira software for 3D reconstruction of LDs and mitochondrial lipid contact sites to elucidate their structure across aging. C_FIG

biophysics↗

bioRxiv2021

Antibody-mediated depletion of human CLEC-2 in a novel humanised mouse model

Platelet C-type lectin-like receptor 2 (CLEC-2) has been proposed as a potential anti-thrombotic target as genetic or antibody-mediated receptor deficiency prevents occlusive thrombus formation in mice. This occurs through interaction with an unknown ligand as the endogenous ligand podoplanin is not present in the vasculature. However, the CLEC-2-podoplanin interaction does have an important role in tumour metastasis. There are currently no methods to test potential human therapeutics targeting CLEC-2, such as antibodies, in vivo. We have therefore generated and characterised a humanised CLEC-2 mouse (hCLEC-2KI) and developed a novel monoclonal anti-human CLEC-2 antibody, HEL1, for in vivo testing. hCLEC-2KI mice were phenotypically normal and had comparable platelet glycoprotein receptor expression, activation and aggregation to wildtype platelets. hCLEC-2KI mice had both comparable bleeding and vessel occlusion times to WT mice. Challenging hCLEC-2KI mice with HEL1 or a second monoclonal anti-hCLEC-2 antibody, AYP1, resulted in transient thrombocytopenia as well as CLEC-2 depletion for more than 2 weeks but had no effect on haemostasis. This illustrates the power of the humanised CLEC-2 mouse model in evaluating novel therapeutics in vivo, including antibodies that target CLEC-2, as well as the limited effect on haemostasis when targeting CLEC-2.

physiology↗

bioRxiv2021

α-Helical peptidic scaffolds to target α-synuclein pathogenic species with high affinity and selectivity.

-Synuclein aggregation is a key driver of neurodegeneration in Parkinsons disease and related syndromes. Accordingly, obtaining a molecule that targets -synuclein pathogenic assemblies with high affinity and selectivity is a long-pursued objective. Here, we have exploited the biophysical properties of toxic oligomers and amyloid fibrils to identify a family of -helical peptides that bind selectively to these -synuclein species with low nanomolar affinity, without interfering with the monomeric functional protein. This activity is translated into an unprecedented anti-aggregation potency and the ability to abrogate the oligomers toxicity. With a structure-function relationship in hand, we identified a human peptide expressed in the brain and in the gastrointestinal tract with exceptional binding, antiaggregation, and detoxifying properties, which suggests it might play a protective role against synucleinopathies. The chemical entities we describe here represent a new therapeutic paradigm and are promising tools to assist diagnosis by selectively detecting -synuclein pathogenic species in biofluids.

biophysics↗

bioRxiv2018

Therapeutic gene editing in hematopoietic progenitor cells from a mouse model of Fanconi anemia

The promising ability to genetically modify hematopoietic stem and progenitor cells (HSPCs) by precise gene editing remains challenging due to their sensitivity and poor permissiveness. This represents the first evidence of implementing a gene editing strategy in a murine safe harbor locus that phenotypically corrects primary cells derived from a mouse model of Fanconi anemia (FA).\n\nBy co-delivering TALENs and a donor therapeutic FANCA cassette template to the Mbs85 locus (ortholog of the hAAVS1 safe harbor locus), we achieved efficient gene targeting (23%) in FA mouse embryonic fibroblasts (MEFs). This resulted in the phenotypic correction of these cells, as revealed by the improvement of their hypersensitivity to mitomycinC. Moreover, robust evidence of targeted integration was observed in murine WT and FA-A hematopoietic progenitor cells (HPC) reaching mean targeted integration values of 20.98% and 16.33% respectively, with phenotypic correction of FA HPCs. Overall, our results demonstrate the feasibility of implementing a therapeutic targeted integration strategy in a murine safe harbor locus, such as the Mbs85 gene, of MEFs and murine HPC from a FA mouse model.

molecular biology↗