Biology subjects

Dubail, M.

Publications and source records attributed to Dubail, M..

4 recordsLinked to original sources

bioRxiv2026

Reprogramming of Lipid Metabolism by FLASH Radiotherapy Selectively Protects Radiosensitive Normal Tissues

FLASH radiotherapy, delivered at ultra-high dose rates exceeding 100 Gy/s, spares normal tissues while maintaining tumor control, yet the molecular mechanisms underlying this differential response remain poorly understood. Here we employed spatial and bulk multi-omics to investigate lipid and protein remodeling in tongue tissue and Mouse oral carcinoma 2 (MOC2) tumors at two weeks post-irradiation with FLASH or conventional dose-rate (CONV) proton radiotherapy. Bulk lipidomics revealed that CONV irradiation induced marked triglyceride (TG) depletion in tongue tissue, whereas FLASH attenuated this depletion. Spatial lipidomics using MALDI-MSI demonstrated that this TG loss was spatially restricted to minor salivary glands, identifying these radiosensitive structures as focal points of radiation-induced lipid damage. Additionally, FLASH irradiation uniquely promoted increases in membrane phospholipids and their lysophospholipid intermediates, consistent with active phospholipid turnover rather than passive damage avoidance. Proteomics revealed divergent metabolic programs: CONV activated a destructive cascade characterized by Ces1d depletion, Acox1-mediated peroxisomal {beta}-oxidation, and Acot7-driven fatty acid overflow, collectively defining a lipid droplet collapse; whereas FLASH engaged a protective program featuring Mgll suppression, Apoe-mediated triglyceride redistribution, and Lypla2-mediated lysophospholipid clearance. We propose a lipid metabolic reprogramming hypothesis in which FLASH not only minimizes acute oxidative damage but actively reprograms lipid metabolism to preserve lipid droplet stores and promote membrane remodeling. These findings provide a putative molecular foundation for the FLASH effect and support published data on the protection of normal tissues.

cancer biology↗

bioRxiv2025

Comparative analysis of the radiobiological effects of laser-driven VHEE vs. conventional electrons using in vitro, ex vivo, and in vivo models

PurposeThis study systematically investigates the radiobiological effects of Very High Energy Electrons (VHEE) generated by a laser-plasma accelerator (LPA), in comparison with Conventional Intermediate Energy Electrons (CIEE) from a conventional linear accelerator (LINAC). Using in vitro, ex vivo, and in vivo models, we evaluate and compare their potential toxicity on healthy tissues. Methods and MaterialsCell survival, tissue response, and developmental toxicity were assessed across three biological models. In vitro, human fibroblasts (MRC5-hTERT) were used to generate post-irradiation survival curves. Ex vivo, precision-cut lung slices (PCLS) from mice were analyzed for radiation-induced inhibition of cell proliferation. In vivo, zebrafish embryos were used to evaluate developmental toxicity through body length and spinal curvature measurements. VHEE irradiations were performed using a broadband electron beam spanning 50-300 MeV, using the Salle Jaune LPA (Laboratoire dOptique Appliquee, France), while CIEE exposures were performed with a 7 MeV conventional LINAC (Institut Curie, France). ResultsIn vitro, MRC5-hTERT cells showed no significant difference in radiosensitivity between VHEE and CIEE, with comparable D10 values (p-value = 0.7). In the ex vivo model, both beams induced a dose-dependent decrease in cell division with no significant inter-beam differences at any dose level (p-value > 0.99). In vivo, zebrafish embryos exhibited dose-dependent body shortening and increased spinal curvature following both VHEE and CIEE exposure. No significant differences were observed between the two modalities at matched doses for any measured metric (p-value[≥] 0.5). ConclusionThis study presents the first comprehensive radiobiological evaluation of a laser-driven VHEE beam across multiple biological models. Under the investigated conditions, VHEE and CIEE irradiations exhibit similar biological toxicity. These findings support the feasibility and potential of VHEE generated with LPA for future clinical applications.

cell biology↗

bioRxiv2024

Radiotherapy triggers pro-angiogenic signaling in human lung

Radiotherapy is one of the main therapeutic options for the treatment of lung cancer. Although highly efficient, radiation cause severe damages to normal tissue and radio-induced toxicities vary from mild pneumonitis to pulmonary fibrosis. The mechanism leading to these toxicities remain unclear. To investigate the molecular responses of human lung to radiotherapy, we analyzed, by single cell RNAseq, lung tissue resected in the vicinity of the tumor (i.e. treated with radiation) and compared the transcriptional profiles of the distinct lung populations from the same patient removed at distance from the tumor (i.e. non-treated with radiation). Analysis of six lung samples from patients suffering from Pancoast tumor, a rare lung malignancy that requires neo-adjuvant radiotherapy before surgery, revealed a strong induction of VEGF signaling after radiotherapy. Expression of VEGFA, one of the canonical pro-angiogenic ligands, was found upregulated in multiple cell populations in lung exposed to high doses of radiation. Irradiated capillaries, particularly gCap cells, expressing KDR/VEGFR2, present transcriptional profile similar to tip cells, characterized by sprouting and motility capacities. In addition, we identified a sub-population of alveolar macrophages expressing FLT1/VEGFR1, a receptor for VEGFA, in lung tissues treated by radiotherapy. Cell-Cell communication analysis revealed that FLT1/VEGFR1 positive macrophages interact with tip cells after radiotherapy through IL1B-IL1R signaling. Lastly, analysis of mouse single cell dataset confirmed the increase in the proportion of gCap cells presenting a tip-like phenotype after radiation injury. Altogether, this study describes, at the single cell level, the pro-angiogenic responses of human lung after radiotherapy. These results will lead to a better understanding of the physiopathology of lung radiation injury and may pave the way to optimize treatments to improve patients quality of life.

cancer biology↗

bioRxiv2024

Conserved signals orchestrate self-organization and symmetry breaking of bi-layered epithelia during development and regeneration

Organ development relies on complex molecular mechanisms that guide initially homogeneous populations of stem cells to differentiate into specialized cell types within defined spatial patterns. While stable during homeostasis, the proper spatial organization of cell types must be re-established in case of tissue injury for successful regeneration of organ shape and function. How cells commit to a differentiation path is a central question in stem cell research; however, the coordination between tissue geometry and cell fate specification remains enigmatic. To elucidate the molecular mechanisms instructing self-organization and symmetry breaking of epithelial stem cells, we developed a multi-faceted approach combining in vitro organoids, ex vivo embryonic tissue explants, and single-cell quantitative imaging to investigate the dynamic acquisition of cell fate in four bi-layered epithelia, during embryonic development but also in regeneration. Our findings indicate that tissue architecture is the primary determinant of cell fate decisions in these tissues. Upon the initial cell internalization event, the homogeneous population of stem cell break symmetry. Through genetic and pharmacological perturbations, we have demonstrated that a tightly coordinated interplay between Hippo/YAP and Notch signaling is essential for conveying information from tissue architecture to functional cell differentiation and stem cell potency restriction. Globally, this study uncovers the inherent capacity of stem cells to self-organize into multicellular structures, where the precise position of each differentiated cell is critical to instruct their differentiation choices during embryonic development and regeneration.

developmental biology↗