New Polyamines Phosphoramidate Vectors for Gene Therapy

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Cationic Lipids Based on Phosphonate and Phosphoramidate Chemistry: Synthesis and Application to Gene Therapy

International audienceCationic lipids having a phosphorus group (phosphonate or phosphoramidate) to link the lipidic part to a cationic head form an efficient family of vectors for DNA delivery. The synthesis of these types of vectors is summarized, including the recent contributions to this field

Biodistribution study of phosphonolipids: A class of non-viral vectors efficient in mice lung-directed gene transfer

International audienceBackground: A multitude of cationic lipids have been synthesized since they were first proposed for use in gene therapy. Cationic lipids are able to efficiently transfect cells both in vitro and in vivo. Whereas most research groups have focused their investigations on the toxicity of these molecules, and on the location of expression of the DNA transferred by these vectors, little has been done to determine their biodistribution and elimination pathways. Our group has developed a family of cationic lipids termed phosphonolipids. Following a large in vitro screening experiment, we have selected several molecules for in vivo testing, with some of these phosphonolipids forming lipoplexes efficient in transfecting mouse lungs. It was thus of interest to study their fate after intravenous injection. Methods: The respective biodistributions of both the GLB43 phosphonolipid and plasmid DNA were investigated and compared with DNA expression sites. Using the optimal conditions determined for phosphonolipids, we followed the gene transfer agent and plasmid DNA distributions versus time by radiolabeling them with 14C and 32P, respectively. Otherwise, we performed imaging by radiolabeling plasmid DNA with 99mTc. Results: The lipoplexes appear to be directly located in the lung after administration. Secondly, the plasmid is released mainly into the lungs and the phosphonolipid vector is rapidly degraded. The hydrophilic moiety of the phosphonolipid is eliminated in the urine, as is the free plasmid. Conclusions: This study reveals that there are slight differences in the observed results depending on the technique used to label the DNA; secondly, results show that the residence time of phosphonolipids in the mouse body is related to the DNA binding time

Biosimilars of filgrastim in autologous stem cell transplantation: certain differences for myeloma patients only.

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Dicationic Lipophosphoramidates as DNA Carriers

International audienceLipophosphoramidates with two different permanent cations as polar heads were synthesized and evaluated for their gene transfer activity. Physicochemical measurements (particle size, zeta potentials) and gel retardation assays were also performed. In vitro biological evaluation was conducted with A542 and HeLa cell lines, and cytotoxicity determined by a chemiluminescent assay. The set of results indicates that, on the whole, dicationic lipophosphoramidates constitute an interesting alternative to their monocationic analogues

Adhesion, proliferation and osteogenic differentiation of human MSCs cultured under perfusion with a marine oxygen carrier on an allogenic bone substitute

International audienceTissue engineering strategies have been developed to optimize osseointegration in dental implant surgery. One of the major problems is the non-homogeneous spatial cell distribution in the scaffold, as well as subsequent matrix production. Insufficient nutrient and oxygen supplies inside the scaffold are factors in this phenomenon. To mediate this gradient formation, we have implemented a perfusion culture method to seed human bone marrow mesenchymal stem cells (MSCs) into three-dimensional (3-D)-allogenic bone scaffolds in combination with a marine haemoglobin, HEMOXCell®, for oxygen delivery. Cell culture was performed under static and perfusion conditions, with standard and osteogenic media, with and without HEMOXCell®. The cell seeding efficiency, as well as MSC/scaffold cytocompatibly were assessed using viability and proliferation assays. Scaffolds' cellularization and extracellular matrix (ECM) formation were analyzed using scanning electron microscopy and histological staining. Cell differentiation was investigated with osteogenic biomarkers gene expression analysis. The perfusion culture was observed to significantly promote MSC proliferation and differentiation throughout the scaffolds, especially when using the induction medium w/HEMOXCell®. Our data suggest that perfusion culture of MSC into allogenic bone substitute with HEMOXCell® as a natural oxygen carrier is promising for tissue engineering applications to oxygenate hypoxic areas and to promote cellular proliferation

Lipophosphoramidates as Lipidic Part of Lipospermines for Gene Delivery

International audienceThe DNA compacting properties of polyamines (especially spermine) are well-known, hence the use of spermine as the cationic part in several synthetic DNA carriers. Here, we describe the synthesis of modified spermines, with a "lipophosphoramidate" as the lipidic part, and their use for efficient in vitro transfection. Physicochemical measurements (particle size, zeta potentials, pKa determination) and gel retardation assays were also performed. Theoretical membrane-disrupting ability was established by FRET. Taken together, our results indicate that lipophosphoramidates constitute an interesting alternative to "classical" lipidic parts of cationic lipids used as DNA carriers