Biology subjects

Mathivet, T.

Publications and source records attributed to Mathivet, T..

6 recordsLinked to original sources

bioRxiv2025

A versatile microfluidic extrusion-based hydrogel platform for self-organization and long-term maintenance of engineered 3D lymphatic endothelium

Lymphatic endothelium is essential for interstitial fluid drainage, immune surveillance, and macromolecular transport. Existing in vitro models that accurately recapitulate its three-dimensional structure, barrier properties, and long-term stability are still limited. In this study, we propose a robust, adaptable, and scalable platform designed to generate engineered three-dimensional lymphatic endothelium using primary human dermal lymphatic endothelial cells (HDLECs). This system combines microfluidic extrusion-based fabrication allowing precise control of the tubular geometry with custom-optimized extracellular matrix-derived hydrogel. The capability to tune dimensions enables the creation of constructs that encompass physiologically relevant size ranges. Through a systematic matrix screen, we identified a unique four-component formulation--gelatin, Matrigel, hyaluronic acid, and fibrinogen--that supports the rapid self-assembly of HDLECs into stable, lumen-forming monolayers within one week. These engineered structures maintain viability and structural integrity for a minimum of 30 days under static culture conditions. Functional permeability assays demonstrated selective tracer uptake characteristics of lymphatic transport. Comparative studies with blood vascular endothelial cells indicate that the proposed platform preserves maintenance of lineage-specific expression profiles, junctional organization, and permeability properties under identical fabrication parameters. Altogether, this approach offers a reproducible and controlled system for studying three-dimensional endothelial architecture, transport mechanisms, and extracellular matrix remodeling across diverse endothelial phenotypes, thereby addressing a pivotal gap in the modeling of lymphatic vasculature. HighlightsO_LIA microfluidic extrusion platform allows primary human lymphatic endothelial cells to self-organize into 3D hollow tubes. C_LIO_LIThe internal dimensions of the hybrid cell/hydrogel constructs can be precisely controlled by tuning the flow rates. C_LIO_LIA custom-defined four-component extracellular matrix provides essential biochemical cues for stable monolayer formation and for the in vitro organization of lymphatic endothelial vessels. C_LIO_LIMatrix composition significantly influences cell proliferation and migration, thereby impacting on the spatial arrangement of the tissue. C_LIO_LIThe three-dimensional lymphatic tissue configuration sustains cell viability, consistent expression of lineage-specific markers, and barrier function which lasts for at least 30 days. C_LIO_LIThe system maintains morphological and functional properties not only for lymphatic endothelial cells, but also for blood endothelial cells in long-term culture conditions. C_LI

bioengineering↗

bioRxiv2024

AURA: Automated Universal RNAscope Analysis for high-throughput applications

In situ hybridization visualizes RNA in cells, but image analysis is complex. We present a protocol based on open-source software for automated high-content multiplex fluorescence in situ transcriptomics analysis. Steps include nuclei segmentation with a Fiji macro and quantification of up to 14 mRNA probes per image. We describe procedures for storing raw data, quality control images and the use of a Python app to summarize all the results in one spreadsheet detailing the number of single or co-positive cells.

cell biology↗

bioRxiv2024

Exploiting a metabolic vulnerability in brain tumour stem cells using a brain-penetrant drug with safe profile

Glioblastoma (GB) remains one of the most treatment refractory and fatal tumour in humans. GB contains a population of self-renewing stem cells, the brain tumour stem cells (BTSC) that are highly resistant to therapy and are at the origin of tumour relapse. Here, we report, for the first time, that mubritinib potently impairs stemness and growth of patient-derived BTSCs harboring different oncogenic mutations. Mechanistically, by employing bioenergetic assays and rescue experiments, we provide compelling evidence that mubritinib acts on complex I of the electron transport chain to impair BTSC stemness pathways, self-renewal and proliferation. Global gene expression profiling revealed that mubritinib alters the proliferative, neural-progenitor-like, and the cell-cycling state signatures. We employed in vivo pharmacokinetic assays to establish that mubritinib crosses the blood-brain barrier. Using preclinical models of patient-derived and syngeneic murine orthotopic xenografts, we demonstrated that mubritinib delays GB tumourigenesis, and expands lifespan of animals. Interestingly, its combination with radiotherapy offers survival advantage to animals. Strikingly, thorough toxicological and behavioral studies in mice revealed that mubritinib does not induce any damage to normal cells and has a well-tolerated and safe profile. Our work warrants further exploration of this drug in in-human clinical trials for better management of GB tumours.

cancer biology↗

bioRxiv2021

Emerging single cell endothelial heterogeneity supports sprouting tumour angiogenesis and growth

Blood vessels supplying tumors are often dysfunctional and generally heterogeneous. The mechanisms underlying this heterogeneity remain poorly understood. Here, using multicolor lineage tracing, in vivo time-lapse imaging and single cell RNA sequencing in a mouse glioma model, we identify tumour-specific blood endothelial cells that originate from cells expressing the receptor for colony stimulating factor 1, Csf1r, a cytokine which controls macrophage biology. These Csf1r lineage endothelial cells (CLECs) form up to 10% of the tumour vasculature and express, besides classical blood endothelial cell markers, a gene signature that is distinct from brain endothelium but shares similarities with lymphatic endothelial cell populations. in silico analysis of pan-cancer single cell RNAseq datasets highlights the presence of a comparable subpopulation in the endothelium of a wide spectrum of human tumours. We show that CLECs actively contribute to sprouting and remodeling of tumour blood vessels and that selective depletion of CLECs reduces vascular branching and tumour growth. Our findings indicate that a non-tumour resident Csf1r-positive population is recruited to tumours, differentiates into blood endothelial cells to contribute to vascularization and, thereby, tumour growth.

cancer biology↗

bioRxiv2021

SLIT2-ROBO signaling in tumor-associated microglia/macrophages drives glioblastoma immunosuppression and vascular dysmorphia

SLIT2 is a secreted polypeptide that guides migration of cells expressing ROBO1&2 receptors. Herein, we investigated SLIT2/ROBO signaling effects in gliomas. In patients with glioblastoma (GBM), SLIT2 expression increased with malignant progression and correlated with poor survival and immunosuppression. Knockdown of SLIT2 in mouse glioma cells and patient derived GBM xenografts reduced tumor growth and synergized with immunotherapy to prolong survival. Tumor cell SLIT2 knockdown inhibited macrophage invasion and promoted a cytotoxic gene expression profile, which improved tumor vessel function and enhanced efficacy of chemotherapy and immunotherapy. Mechanistically, SLIT2 promoted microglia/macrophage chemotaxis and tumor-supportive polarization via ROBO1&2-mediated PI3K{gamma} activation. Macrophage Robo1&2 deletion and systemic SLIT2 trap delivery mimicked SLIT2 knockdown effects on tumor growth and the tumor microenvironment (TME), revealing SLIT2 signaling through macrophage ROBOs as a novel regulator of the GBM microenvironment and a potential immunotherapeutic target for brain tumors.

cancer biology↗

bioRxiv2021

TGF-beta promotes microtube formation in glioblastoma through Thrombospondin 1

Microtubes (MTs), cytoplasmic extensions of glioma cells, are important cell communication structures promoting invasion and treatment resistance through network formation. MTs are abundant in chemoresistant gliomas, in particular glioblastomas (GBMs), while they are uncommon in chemosensitive IDH-mutant and 1p/19q co-deleted oligodendrogliomas. To identify potential signaling pathways involved in MT formation we performed a bioinformatics analysis of TCGA data showing that the TGF-{beta} pathway is highly activated in GBMs compared to oligodendroglial tumors. In particular we observed that signaling pathways involved in extracellular matrix organization are differentially expressed between these tumor entities. Using patient-derived GBM stem cell lines, we demonstrated that TGF-{beta}1 stimulation promotes enhanced MT formation and communication via Calcium signaling. Inhibition of the TGF-{beta} pathway significantly reduced MT formation and its associated invasion in vitro and in vivo. Downstream of TGF-{beta}, we identified thrombospondin 1 (TSP1) as a potential mediator of MT formation in GBM through SMAD activation. TSP1 was upregulated upon TGF-{beta} stimulation and enhanced MT formation, which was inhibited by TSP1 shRNAs in vitro and in vivo. In conclusion, TGF-{beta} and its downstream mediator TSP1 are important mediators of the MT network in GBM and blocking this pathway could potentially help to break the complex MT driven invasion/ resistance network.

cancer biology↗