Biology subjects

Delalande, F.

Publications and source records attributed to Delalande, F..

7 recordsLinked to original sources

bioRxiv2025

Monitoring the dynamics of exosomes through the tracking of Rab7 partners

Extracellular vesicles (EVs) play a crucial role in cell-cell signaling, and their dysregulation is linked to various pathologies. EVs can originate from the plasma membrane as microvesicles, or form within endosomal compartments that fuse with the plasma membrane, releasing their intraluminal vesicles in the extracellular space as exosomes. However, distinguishing between these two types of EVs is challenging due to their common protein markers, necessitating cumbersome isolation methods. To overcome this limitation, we developed an innovative tool using Rab7-mediated proximity labelling and mass spectrometry. This technological advancement enables the covalent labeling of Rab7 partners allowing the tracking of intracellular and extracellular exosomal cargoes.

cell biology↗

bioRxiv2023

Peripheral positioning of lysosomes supports melanoma aggressiveness

Emerging evidences suggest that function and position of organelles are pivotal for tumor cell dissemination. Among them, lysosomes stand out as they integrate metabolic sensing with gene regulation and secretion of proteases. Yet, how their function is linked to their position and how this controls metastasis remains elusive. Here, we analyzed lysosome subcellular distribution in patient-derived melanoma cells and patient biopsies and found that lysosome spreading scales with their aggressiveness. Peripheral lysosomes promote matrix degradation and invasion of melanoma cells which is directly linked to their lysosomal and cell transcriptional programs. When controlling lysosomal positioning using chemo-genetical heterodimerization in patient-derived melanoma cells, we demonstrated that perinuclear clustering impairs lysosomal secretion, matrix degradation and invasion. Impairing lysosomal spreading in two distinct in vivo models (mouse and zebrafish) significantly reduces invasive outgrowth. Our study provides a direct demonstration that lysosomal positioning controls cell invasion, illustrating the importance of organelle adaptation in carcinogenesis and suggesting that lysosome positioning could potentially be used for the diagnosis of metastatic melanoma.

cell biology↗

bioRxiv2022

The Holdup Multiplex, an assay for high-throughput measurement of protein-ligand affinity constants using a mass-spectrometry readout

The accurate description and subsequent modeling of protein interactomes requires quantification of their affinities at proteome-wide scale. Here we develop and validate the Holdup Multiplex, a versatile assay for high-throughput measurement of protein-ligand affinity constants that uses mass-spectrometry as readout. The method can quantify thousands of affinities in one single run, with high precision and over several orders of magnitude. We applied this strategy to the seven human 14-3-3 isoforms, quantifying in a few sample-runs their interaction with 1,000 different phosphopeptides. We were able to identify hundreds of new 14-3-3 binding sites. We showed that the seven human 14-3-3 display similar specificities but staggered affinities, 14-3-3g being always the best binder and 14-3-3{varepsilon} and {sigma}, the weakest. Finally, we identified dozens of 14-3-3 bindings sites, some intervening in key signaling pathways, that were either stabilized or destabilized by the phytotoxin Fusicoccin-A. Our approach, which throughput can be pushed up to the sensitivity limit of the mass-spectrometry setup, is applicable to any category of protein-ligand interactions and thus bears a wide potential both for high-throughput interactomics and chemoproteomics.

systems biology↗

bioRxiv2022

Trans-synaptic dwelling of SARS-CoV-2 particles perturbs neural synapse organization and function

SARS-CoV-2 infection is associated with short- and long-term neurological and psychiatric complications, referred to as neuroCOVID. These symptoms are relatively heterogenous and fluctuating, hampering the discovery of molecular mechanisms underlying viro-induced brain perturbations. Here, we show that the human cerebral cortex poorly supports SARS-CoV-2 dissemination using post-mortem COVID-19 patient samples, ex vivo organotypic cultures of human brain explants and stem cell-derived cortical organoids. Despite restricted infection, the sole exposure of neural cells to SARS-CoV-2 particles is sufficient to induce significant perturbations on neural synapse organization associated to electrical activity dysfunction. Single-organoid proteomics revealed that exposure to SARS-CoV-2 is associated to trans-synaptic proteins upregulation and unveiled that incoming virions dwell at LPHN3/FLRT3-containing synapses. Our study provides new mechanistic insights on the origin of SARS-CoV-2-induced neurological disorders. One-Sentence SummarySARS-CoV-2 modulates neural plasticity and electrical activity as viral particles lodge at the trans-synaptic interface.

microbiology↗

bioRxiv2022

The Emergence of the Metabolic Signaling of the Nucleoredoxin-like Genes during Evolution

The nucleoredoxin-like genes NXNL1 and NXNL2 were identified through the biological activity of rod-derived cone viability factors (RdCVF and RdCVF2), the alternatively spliced variants produced by intron retention, that mediate signaling between rod and cone photoreceptors by stimulating glucose uptake. These therapeutic genes for inherited retinal degenerations also produce by splicing thioredoxin-like proteins that reduce oxidized cysteines in photoreceptor proteins. The first NXNL genes date from the first animal phyla. Intron retention produces an active RdCVF protein in the tentacles of Hydra vulgaris, a species without eyes. A Scallop RdCVF protein is produced by ciliated photoreceptors of the retina and binds its receptor, BSG1. In the lamprey, a descendent of early vertebrates, RdCVF metabolic signaling between rod and cones is fully established. In the mouse, the production of BSG1 by photoreceptors is regulated by cell-specific splicing inhibition. RdCVF signaling predates photoreceptors and evolved through two alternative splicing events.

evolutionary biology↗

bioRxiv2020

CRISPR-based bioengineering of the Transferrin Receptor revealed a role for Rab7 in the biosynthetic secretory pathway

The regulated secretory trafficking of neosynthesized transmembrane receptors is particularly challenging to investigate as it is under-represented at steady state compared to the abundance of the other trafficking routes. Here, we combined the retention using selective hook (RUSH) system to a CRISPR/Cas9 gene editing approach (eRUSH) to identify molecular players involved in the trafficking of neosynthesized Transferrin Receptor (TfR) en route to the plasma membrane (PM). TfR-eRUSH monoclonal cells expressing endogenous, ER-retainable and fluorescent TfR were engineered and characterized. Spatiotemporal quantitative proteomics of TfR-eRUSH cells allowed the identification of molecular partners associated with TfR-containing membranes and provided a comprehensive list of potential regulators, co-trafficking cargos, and enriched pathways. Furthermore, we chose to focus our attention on the Rab GTPase family members for their function as vesicle trafficking regulators and performed a Rab-targeted siRNA screen that we correlated to our proteomics data. Unexpectedly, we identified Rab7-harboring vesicles as an intermediate compartment of the Golgi-to-PM transport of the neosynthetic TfR. These vesicles did not exhibit degradative properties and were not associated to Rab6A-harboring vesicles, also involved in Golgi-to-PM transport. However, Rab6A-TfR vesicles delivered TfR directly to the PM, while in contrast, Rab7A was transiently associated to neosynthetic TfR-containing post-Golgi vesicles but dissociated before PM vesicle fusion. Together, our study proposes the eRUSH as a powerful tool to further study the secretory pathway and reveals an unforeseen role for Rab7 in the neosynthetic transport of the TfR, highlighting the diversity of the secretory vesicles nature for a given cargo.

cell biology↗

bioRxiv2018

Studying the fate of tumor extracellular vesicles at high spatio-temporal resolution using the zebrafish embryo

Tumor extracellular vesicles (tumor EVs) mediate the communication between tumor and stromal cells mostly to the benefit of tumor progression. Notably, tumor EVs have been reported to travel in the blood circulation, reach specific distant organs and locally modify the microenvironment. However, visualizing these events in vivo still faces major hurdles. Here, we show a new method for tracking individual circulating tumor EVs in a living organism: we combine novel, bright and specific fluorescent membrane probes, MemBright, with the transparent zebrafish embryo as an animal model. We provide the first description of tumor EVs hemodynamic behavior and document their arrest before internalization. Using transgenic lines, we show that circulating tumor EVs are uptaken by endothelial cells and blood patrolling macrophages, but not by leukocytes, and subsequently stored in acidic degradative compartments. Finally, we prove that the MemBright can be used to follow naturally released tumor EVs in vivo. Overall, our study demonstrates the usefulness and prospects of zebrafish embryo to track tumor EVs in vivo.\n\nHighlightsO_LIMemBright, a new family of membrane probes, allows for bright and specific staining of EVs\nC_LIO_LIZebrafish melanoma EVs are very similar to human and mouse melanoma EVs in morphology and protein content\nC_LIO_LIThe zebrafish embryo is an adapted model to precisely track tumor EVs dynamics and fate in a living organism from light to electron microscopy\nC_LIO_LICirculating tumor EVs are rapidly uptaken by endothelial cells and patrolling macrophages\nC_LIO_LICorrelated light and electron microscopy can be used in zebrafish to identify cells and compartments uptaking tumor EVs\nC_LI\n\nBlurbDispersion of tumor extracellular vesicles (EVs) throughout the body promotes tumor progression. However the behavior of tumor EVs in body fluids remains mysterious due to their small size and the absence of adapted animal model. Here we show that the zebrafish embryo can be used to track circulating tumor EVs in vivo and provide the first high-resolution description of their dissemination and uptake.

cell biology↗