Biology subjects

Leroux, J.-C.

Publications and source records attributed to Leroux, J.-C..

7 recordsLinked to original sources

bioRxiv2024

Rapid selection of transgenic mammalian cells via diphtheria toxin resistance

The ability to generate stable transgenic mammalian cell lines is crucial to the investigation of gene functions and the production of recombinant proteins. Currently, mammalian cells can be readily transfected in cell culture settings via both viral and nonviral vectors to induce transgene expression. However, there is an unmet need for efficient selection of transfected cells, since current methods involve rather inefficient antibiotic selection protocols or require the coexpression of fluorescent marker proteins, followed by laborious cell sorting procedures. Our aim was to implement a rapid and efficient in situ selection approach for transgene-expressing human cells, using an engineered diphtheria toxin (DT) resistance-based selection, referred to as selecDT. We demonstrated that selecDT is expressed on the surface of modified human cells, provides efficient protection from DT by inactivating its uptake receptor, and, therefore, enables selection. Current antibiotic-based methods require selection periods of more than a week and often achieve only limited cell enrichment. With selecDT, one day of selection is sufficient to obtain nearly 100% enrichment. The DT resistance described herein may thus positively impact biotechnological processes and biomedical research.

bioengineering↗

bioRxiv2024

Loading of extracellular vesicles with nucleic acids via hybridization with sponge-like lipid nanoparticles

The translation of cell-derived extracellular vesicles (EVs) into biogenic gene delivery systems is limited by relatively inefficient loading strategies. In this work, we describe the loading of various nucleic acids into small EVs via their spontaneous hybridization with preloaded non-lamellar liquid crystalline lipid nanoparticles (LCNPs) under physiological conditions, forming hybrid EVs (HEVs). We correlate LCNPs topological characteristics with their propensity to fuse/aggregate with EVs and found that sponge (L3) phases at pH 7.4 were particularly suitable to induce a controlled hybridization process. State-of-the-art single-particle analysis techniques revealed that L3-based LCNPs interact with various EV subpopulations and that around 40% of HEVs were loaded with the genetic cargo. Importantly, this study demonstrates that EV membrane proteins remain accessible on HEV surfaces, with their intrinsic enzymatic activity unaffected after the hybridization process. Finally, HEVs showed in vitro improved transfection efficiencies compared to unhybridized LCNPs. In summary, this versatile platform holds potential for loading various nucleic acid molecules into native EVs and may help developing EV-based therapeutics. TeaserTopology of lipid nanoparticles influences their hybridization behavior with extracellular vesicles and produces novel biogenic gene delivery systems.

bioengineering↗

bioRxiv2020

Three-dimensional Printing of Customized Bioresorbable Airway Stents

Central airway obstruction is a life-threatening disorder causing a high physical and psychological burden to patients due to severe breathlessness and impaired quality of life. Standard-of-care airway stents are silicone tubes, which cause immediate relief, but are prone to migration, especially in growing patients, and require additional surgeries to be removed, which may cause further tissue damage. Customized airway stents with tailorable bioresorbability that can be produced in a reasonable time frame would be highly needed in the management of this disorder. Here, we report poly(D,L-lactide-co-{varepsilon}-caprolactone) methacrylate blends-based biomedical inks and their use for the rapid fabrication of customized and bioresorbable airway stents. The 3D printed materials are cytocompatible and exhibit silicone-like mechanical properties with suitable biodegradability. In vivo studies in healthy rabbits confirmed biocompatibility and showed that the stents stayed in place for 7 weeks after which they became radiographically invisible. The developed biomedical inks open promising perspectives for the rapid manufacturing of the customized medical devices for which high precision, tuneable elasticity and predictable degradation are sought-after.

bioengineering↗

bioRxiv2020

Elucidating the mechanism of cyclodextrins in the treatment of Niemann-Pick Disease Type C using crosslinked 2-hydroxypropyl-β-cyclodextrin

Niemann-Pick Disease Type C (NPC) is a severe neurovisceral disorder that is pathophysiologically characterized by intracellular transport abnormalities leading to cytoplasmic accumulation of lipids such as cholesterol and multiple sphingolipids, including sphingosine. The compound 2-hydroxypropyl-{beta}-cyclodextrin (HP{beta}CD) is a compound with high cholesterol complexation capacity and is currently under clinical investigation for the treatment of NPC. However, due to its short blood half-life, high doses are required to produce a therapeutic effect. It has been reported in mice that HP{beta}CDs circulation time and efficacy can be improved by increasing its size via polymerization, but the biodegradable nature of these systems did not allow the contribution of the macromolecule to the activity to be determined. In this work, stable forms of polymerized HP{beta}CD were generated (via epichlorohydrin crosslinking) to investigate their in vitro mechanisms of action and in vivo effects. Crosslinked CDs (8-312 kDa) displayed a 10-fold greater complexation capacity towards cholesterol than monomeric HP{beta}CD but were taken up by cells to a lower extent (in a size-dependent fashion), resulting in an overall comparable in vitro effect on intracellular cholesterol accumulation that was dependent on cholesterol complexation. When tested in vivo, the crosslinked 19.3 kDa HP{beta}CD exhibited a longer terminal half-life than the monomeric HP{beta}CD. However, it did not increase the life span of Npc1 mice, possibly due to reduced organ penetration and brain diffusion consequence of its large molecular weight. This could be circumvented by the application of magnetic resonance imaging-guided low intensity-pulsed focused ultrasound (MRIg-FUS), which increased the brain penetration of the CD. In conclusion, stable forms of polymerized HP{beta}CD constitute valuable tools to elucidate CDs mechanism of action. Moreover, the use of MRIg-FUS to maximize CDs tissue penetration warrants further investigation, as it may be key to harnessing CDs full therapeutic potential in the treatment of NPC. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=107 SRC="FIGDIR/small/230136v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@3dbaf1org.highwire.dtl.DTLVardef@bc255dorg.highwire.dtl.DTLVardef@390e7borg.highwire.dtl.DTLVardef@1e5e5c5_HPS_FORMAT_FIGEXP M_FIG C_FIG The 2-hydroxypropyl-{beta}-cyclodextrin (HP{beta}CD) is a well-established pharmaceutical excipient that can complex cholesterol and is currently under clinical investigation to treat Niemann-Pick Disease Type C (NPC). However, high doses of the drug are needed to achieve a therapeutic effect. Using stable and long circulating crosslinked HP{beta}CDs, this study attempts to further understand the mechanisms behind CDs activity.

pharmacology and toxicology↗

bioRxiv2019

A microparticulate based formulation to protect therapeutic enzymes from proteolytic digestion: phenylalanine ammonia lyase as case study

Phenylketonuria is a genetic disorder affecting the metabolism of phenylalanine (phe) due to a deficiency in the enzyme phenylalanine hydroxylase. This disorder is characterized by an elevated phe blood level, which can lead to severe intellectual disabilities in newborns. The current strategy to prevent these devastating consequences is limited to a life-long phe-free diet, which implies major lifestyle changes and restrictions. Recently, an injectable enzyme replacement therapy, Pegvaliase, has been approved for treating phenylketonuria, but is associated with significant side-effects. In this study a phe-metabolizing system suitable for oral delivery is designed to overcome the need for daily injections. Active phenylalanine ammonia-lyase (PAL), an enzyme that catalyzes phe metabolism, is loaded into mesoporous silica microparticles (MSPs) with pore sizes ranging from 10 to 35 nm. The surface of the MSPs is lined with a semipermeable barrier to allow permeation of phe while blocking digestive enzymes that degrade PAL. The enzymatic activity can be partially preserved in vitro by coating the MSPs with poly(allylamine) and poly(acrylic acid)-bowman birk (protease inhibitor) conjugate. The carrier system presented herein may provide a general approach to overcome gastro-intestinal proteolytic digestion and to deliver active enzymes to the intestinal lumen for prolonged local action.

bioengineering↗

bioRxiv2019

An investigation of PS-b-PEO polymersomes for the oral treatment and diagnosis of hyperammonemia

Ammonia-scavenging transmembrane pH-gradient poly(styrene)-b-poly(ethylene oxide) polymersomes were investigated for the oral treatment and diagnosis of hyperammonemia, a condition associated with serious neurologic complications in patients with liver disease as well as in infants with urea cycle disorders. While these polymersomes were highly stable in simulated intestinal fluids at extreme bile salt and osmolality conditions, they unexpectedly did not reduce plasmatic ammonia levels in cirrhotic rats after oral dosing. Incubation in dietary fiber hydrogels mimicking the colonic environment suggested that the vesicles were probably destabilized during the dehydration of the intestinal chyme. Our findings question the relevance of commonly used simulated intestinal fluids for studying vesicular stability. With the encapsulation of a pH-sensitive dye in the polymersome core, the local pH increase upon ammonia influx could be exploited to assess the ammonia concentration in the plasma of healthy and cirrhotic rats as well as in other fluids. Due to its high sensitivity and selectivity, this novel polymersome-based assay could prove useful in the monitoring of hyperammonemic patients and in other applications such as drug screening tests.\n\nGraphical abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=94 SRC=\"FIGDIR/small/631630v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (28K):\norg.highwire.dtl.DTLVardef@dd9b02org.highwire.dtl.DTLVardef@ebb129org.highwire.dtl.DTLVardef@1bc15e3org.highwire.dtl.DTLVardef@1411a28_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2019

Dual delivery of nucleic acids and PEGylated-bisphosphonates via calcium phosphate nanoparticles

Despite many years of research and a few success stories with gene therapeutics, efficient and safe DNA delivery remains a major bottleneck for the clinical translation of gene-based therapies. Gene transfection with calcium phosphate (CaP) nanoparticles brings the advantages of low toxicity, high DNA entrapment efficiency and good endosomal escape properties. The macroscale aggregation of CaP nanoparticles can be easily prevented through surface coating with bisphosphonate conjugates. Bisphosphonates, such as alendronate, recently showed promising anticancer effects. However, their poor cellular permeability and preferential bone accumulation hamper their full application in chemotherapy. Here, we investigated the dual delivery of plasmid DNA and alendronate using CaP nanoparticles, with the goal to facilitate cellular internalization of both compounds and potentially achieve a combined pharmacological effect on the same or different cell lines. A pH-sensitive poly(ethylene glycol)-alendronate conjugate was synthetized and used to formulate stable plasmid DNA-loaded CaP nanoparticles. These particles displayed good transfection efficiency in cancer cells and a strong cytotoxic effect on macrophages. The in vivo transfection efficiency, however, remained low, calling for an improvement of the system, possibly with respect to the extent of particle uptake and their physical stability.\n\nGraphical abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=78 SRC=\"FIGDIR/small/621102v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (29K):\norg.highwire.dtl.DTLVardef@5f5d56org.highwire.dtl.DTLVardef@e8bc5eorg.highwire.dtl.DTLVardef@1a6f000org.highwire.dtl.DTLVardef@d690d8_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗