Biology subjects

Lavieu, G.

Publications and source records attributed to Lavieu, G..

4 recordsLinked to original sources

bioRxiv2024

Therapeutic potential of human mesenchymal stromal cell-derived mitochondria in a rat model of post-surgical digestive fistula: towards an energetic nano-biotherapy

BackgroundTissue regeneration heavily relies on cellular energy production, with mitochondria playing a crucial role. Dysfunctional mitochondria are implicated in various degenerative diseases, driving interest in targeting mitochondrial transplantation for tissue repair. Wound healing is highly compromised in gastrointestinal conditions resulting in fistula development, particularly after sleeve gastrectomy. Human mesenchymal stem/stromal cells (hMSCs) and their cell-free products such as mitochondria offer potential benefits due to their therapeutic properties on cellular energy production. Here we investigated the therapeutic advantage of hMSCs-derived mitochondria nano-biotherapy in a rat model of post-surgical fistula healing. MethodsViable and structurally intact mitochondria were isolated from hMSCs before exposure to human colonic epithelial cells (HCEC-1CT) culture or transplantation into a rat model of post-operative fistula. ResultsOur findings reveal significant dose-dependent improvement on cellular metabolic activity and ATP content of the recipient cells. Assessment of the external fistula orifice developed following post sleeve gastrectomy fistula, revealed a substantial healing in all transplanted rats compared to control group. ConclusionOur findings highlight the therapeutic potential of hMSCs-derived mitochondria in post-surgical fistula healing. This research contributes to advancing cell-free regenerative strategies for gastrointestinal conditions, offering new insights into mitochondrial-based therapies for enhancing wound healing and tissue repair.

systems biology↗

bioRxiv2022

Cholesterol and ceramide facilitate SARS-CoV-2 Spike protein-mediated membrane fusion

SARS-CoV-2 entry into host cells is mediated by the Spike (S) protein of the viral envelope. The S protein is composed of two subunits: S1 that induces binding to the host cell via its interaction with the ACE2 receptor of the cell surface and S2 that triggers fusion between viral and cellular membranes. Fusion by S2 depends on its heptad repeat domains that bring membranes close together, and its fusion peptide (FP) that interacts with and perturb the membrane structure to trigger fusion. Recent studies suggest that cholesterol and ceramide lipids from the cell surface may facilitate SARS-CoV-2 entry into host cells, but their exact mode of action remains unknown. We have used a combination of in vitro liposome-liposome and in situ cell-cell fusion assays to study the lipid determinants of S-mediated membrane fusion. We found that cholesterol and ceramide both facilitated fusion, suggesting that targeting lipids could be effective against SARS-CoV-2. As proof of concept, we examined the effect of chlorpromazine (CPZ), an antipsychotic drug known to perturb membrane structure. We found that CPZ inhibited S-mediated membrane fusion and thus potentially SARS-CoV-2 entry.

biophysics↗

bioRxiv2021

Homosalate boosts the release of tumor-derived Extracellular Vesicles with anti-anoikis properties

Eukaryotic cells, including cancer cells, secrete highly heterogeneous populations of extracellular vesicles (EVs). EVs could have different subcellular origin, composition and functional properties, but tools to distinguish between EV subtypes are scarce. Here, we tagged CD63- or CD9-positive EVs secreted by triple negative breast cancer cells with Nanoluciferase enzyme, to set-up a miniaturized method to quantify secretion of these two EV subtypes directly in the supernatant of cells. We performed a cell-based high-content screening to identify clinically-approved drugs able to affect EV secretion. One of the identified hits is Homosalate, an anti-inflammatory drug found in sunscreens which robustly increased EVs release. Comparing EVs induced by Homosalate with those induced by Bafilomycin A1, we discovered that: 1) the two drugs act on EVs generated in distinct subcellular compartments and 2) EVs released upon treatment with Homosalate, but not with Bafilomycin A1, conferred anti-anoikis properties to another recipient tumor cell line. In conclusion, we identified a new drug modifying EV release and demonstrated that under influence of different drugs, triple negative breast cancer cells release EV subpopulations from different subcellular origins harboring distinct functional properties.

cell biology↗

bioRxiv2017

Light-Activated Cell Identification and Sorting (LACIS): A New Method to Identify and Select Edited Clones on a Microfluidic Device

CRISPR-Cas9 gene editing has revolutionized cell engineering and promises to open new doors in gene and cell therapies. Despite improvements in the CRISPR-editing molecular toolbox in cell lines and primary cells, identifying and purifying properly edited clones remains slow, laborious and low-yield. Here, we establish a new method that uses cell manipulation on a chip with Opto-Electronic Positioning (OEP) technology to enable clonal isolation and selection of edited cells. We focused on editing CXCR4 in primary human T cells, a gene that encodes a co-receptor for HIV entry. T cells hold significant potential for cell-based therapy, but the gene-editing efficiency and expansion potential of these cells is limited. We describe here a method to obviate these limitations. Briefly, after electroporation of cells with CXCR4-targeting Cas9 ribonucleoproteins (RNPs), single T cells were isolated on a chip, where they proliferated over time into well-resolved colonies. Phenotypic consequences of genome editing could be rapidly assessed on-chip with cell-surface staining for CXCR4. Furthermore, independent of phenotype, individual colonies could be identified based on their specific genotype at the 5-10 cell stage. Each colony was split and sequentially exported for immediate on-target sequencing and validation, and further off-chip clonal expansion of the validated clones. We were able to assess single-clone editing efficiencies, including the rate of monoallelic and biallelic indels or precise nucleotide replacements. This new method will enable identification and selection of perfectly edited clones within 10 days from Cas9-RNP introduction in cells based on the phenotype and/or genotype.

bioengineering↗