Biology subjects

Tessier, C.

Publications and source records attributed to Tessier, C..

3 recordsLinked to original sources

bioRxiv2026

Birth by Cesarean Section Remodels Neonatal Brain Barriers and Associated Immune and Metabolic Pathways in Mice

Delivery mode shapes early-life physiology through multiple pathways, including stress and hormonal signalling, neonatal oxygenation, and exposure to maternal microbes. Cesarean section (CS) bypasses several of these processes and has been associated with altered immune maturation and neurodevelopmental outcomes in humans and animal models. Given that CS is known to disrupt gut barrier integrity and that gut and brain barriers operate as a coordinated network, we investigated whether CS affects early postnatal brain barriers. Using a mouse model, we compared CS-delivered pups to vaginally born (VB) controls at postnatal days 8-9. Brain barrier permeability and structure were assessed using tracer extravasation and vascular and tight junction analyses, choroid plexus immune populations were profiled, and metabolomics was performed in cortex and plasma. The blood-brain barrier in the medial prefrontal cortex was mostly preserved. In contrast, the blood-cerebrospinal fluid barrier (BCSFB) exhibited structural alterations in vascular and epithelial tight junction compartments. These changes were accompanied by immune remodelling, including expansion of antigen-presenting border-associated macrophages and reduced parenchymal microglia density. CS delivery increased brain tracer accumulation, consistent with altered barrier function during this developmental window. Metabolomic analyses revealed lower levels of key brain metabolites, including N-acetylaspartate, a marker of neuronal metabolic state. Together, these findings demonstrate that CS delivery induces early alterations in brain barrier function, BCSFB structure, the immune landscape, and metabolic profiles in mice. This identifies delivery mode as a key perinatal variable shaping neonatal brain physiology and establishes a framework for dissecting how birth context may influence long-term neurodevelopmental trajectories. HIGHLIGHTSO_LICesarean section (CS) reveals the neonatal BCSFB as a vulnerable interface shaped by birth mode C_LIO_LICS increases brain tracer accumulation despite largely preserved BBB structural markers at the mPFC C_LIO_LICS induces region-specific vascular, epithelial, and immune remodeling in the choroid plexus C_LIO_LICesarean birth increases the proportion of antigen-presenting choroid plexus macrophages C_LIO_LICS shifts mPFC metabolic profiles, including reduced N-acetylaspartate and malate C_LI

neuroscience↗

bioRxiv2024

Primary cilia promote EMT-induced triple-negative breast tumor heterogeneity and resistance to therapy

Tumor heterogeneity and plasticity, driven by Epithelial-Mesenchymal Transition (EMT), enable cancer therapeutic resistance. We previously showed that EMT promotes primary cilia formation, which enables stemness and tumorigenesis in triple-negative breast cancer (TNBC). Here, we establish a role for primary cilia in human TNBC chemotherapeutic resistance. We developed patient-derived organoids, and showed that these recapitulated the cellular heterogeneity of TNBC biopsies. Notably, one of the identified cell states bore a quasi-mesenchymal phenotype, primary cilia, and stemness signatures. We treated our TNBC organoids with chemotherapeutics and observed partial killing. The surviving cells with organoid-reconstituting capacity showed selective enrichment for the quasi-mesenchymal ciliated cell subpopulation. Genomic analyses argue that this enrichment reflects a combination of pre-existing cells and ones that arose through drug-induced cellular plasticity. We developed a family of small-molecule inhibitors of ciliogenesis and show that these, or genetic ablation of primary cilia, suppress chemoresistance. We conclude that primary cilia help TNBC to evade chemotherapy. SignificanceCancer cells that activate EMT to acquire a quasi-mesenchymal state form primary cilia to evade chemotherapy in human triple-negative breast cancer. Pharmacological inhibition of primary ciliogenesis counteracts EMT-induced chemoresistance.

cancer 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↗