Papers by Jean-Sébastien Thomann
Pharmaceutical Research, Sep 10, 2008
Purpose. To design and evaluate liposomal constructs capable of inducing a potent systemic and ai... more Purpose. To design and evaluate liposomal constructs capable of inducing a potent systemic and airway humoral response to Pseudomonas aeruginosa Methods. Liposomes contained a peptide derived from P. aeruginosa pilin protein as B epitope, a peptide derived from Influenza hemagglutinin protein as Th epitope, the TLR agonist Pam 3 CAG or Pam 2 CAG as adjuvant, and a mannosylated lipid as dendritic cell targeting agent. These constructions were administered to mice intraperitoneally (i.p.) or intranasally (i.n.). Their immunogenicity was evaluated by measuring B epitope-specific immunoglobulins in the serum and the airways by ELISA. Results. The B epitope, in its native form or after substitution of a cysteine by a serine, induced high systemic IgG titers when formulated in the presence of Pam 3 CAG or Pam 2 CAG and administered i.p.. No IgA response was observed in the airways upon injection of candidate vaccines by i.p. route, whatever the B epitope or the adjuvant. However, i.n. vaccination resulted in a significant local production of IgA. Finally, the production of IgG was more rapid when mannose was incorporated. Conclusions. All liposomal candidate vaccines tested induced the production of IgG and/or IgA directed against an immunogenic peptide from P. aeruginosa. Liposomal constructs could be attractive in the vaccination against P. aeruginosa.
International Journal of Pharmaceutics, Sep 1, 2017
The potent antitumor effect of α-galactosylceramide (α-GalCer) is based on its recognition by inv... more The potent antitumor effect of α-galactosylceramide (α-GalCer) is based on its recognition by invariant Natural Killer T cells (iNKT) after its capture and presentation by antigen presenting cells including dendritic cells (DCs). Synthetic α-GalCer has already been tested in advanced cancer patients but no or only moderate clinical responses were obtained. To optimize α-GalCer efficacy, we have postulated that alternative formulations impacting its molecular organization in aqueous medium could modify DC uptake and iNKT-based immune responses. To this end, we have developed two strategies: (1) the formulation of α-GalCer in non-cationic liposomes and (2) the synthesis of a water-soluble α-GalCer analogue by anchoring a polyethyleneglycol moiety on its sugar head. The biological activities of these new preparations were compared to that induced by the classically used Polysorbate 20 α-GalCer micelles. Both formulations retained their uptake by DCs and activated iNKT cells both in vitro and in vivo. Despite a lower cytokine production, the formulations induced a potent immune response able to control lung murine carcinoma. In conclusion, it is possible to increase α-GalCer solubility in aqueous solution without limiting its antitumor properties. Abbreviations α-GalCer-PEG: water-soluble α-GalCer m-α-GalCer: α-GalCer-containing polysorbate micelles (micellar solution) REV α-GalCer: α-GalCer-containing reverse-phase evaporation vesicles (liposomes) SUV α-GalCer: α-GalCer-containing small unilamellar vesicles (liposomes)
Angewandte Chemie, Apr 14, 2011
International Journal of Pharmaceutics, 2017
The potent antitumor effect of α-galactosylceramide (α-GalCer) is based on its recognition by inv... more The potent antitumor effect of α-galactosylceramide (α-GalCer) is based on its recognition by invariant Natural Killer T cells (iNKT) after its capture and presentation by antigen presenting cells including dendritic cells (DCs). Synthetic α-GalCer has already been tested in advanced cancer patients but no or only moderate clinical responses were obtained. To optimize α-GalCer efficacy, we have postulated that alternative formulations impacting its molecular organization in aqueous medium could modify DC uptake and iNKT-based immune responses. To this end, we have developed two strategies: (1) the formulation of α-GalCer in non-cationic liposomes and (2) the synthesis of a water-soluble α-GalCer analogue by anchoring a polyethyleneglycol moiety on its sugar head. The biological activities of these new preparations were compared to that induced by the classically used Polysorbate 20 α-GalCer micelles. Both formulations retained their uptake by DCs and activated iNKT cells both in vitro and in vivo. Despite a lower cytokine production, the formulations induced a potent immune response able to control lung murine carcinoma. In conclusion, it is possible to increase α-GalCer solubility in aqueous solution without limiting its antitumor properties. Abbreviations α-GalCer-PEG: water-soluble α-GalCer m-α-GalCer: α-GalCer-containing polysorbate micelles (micellar solution) REV α-GalCer: α-GalCer-containing reverse-phase evaporation vesicles (liposomes) SUV α-GalCer: α-GalCer-containing small unilamellar vesicles (liposomes)
Pharmaceutical Research, 2008
Purpose. To design and evaluate liposomal constructs capable of inducing a potent systemic and ai... more Purpose. To design and evaluate liposomal constructs capable of inducing a potent systemic and airway humoral response to Pseudomonas aeruginosa Methods. Liposomes contained a peptide derived from P. aeruginosa pilin protein as B epitope, a peptide derived from Influenza hemagglutinin protein as Th epitope, the TLR agonist Pam 3 CAG or Pam 2 CAG as adjuvant, and a mannosylated lipid as dendritic cell targeting agent. These constructions were administered to mice intraperitoneally (i.p.) or intranasally (i.n.). Their immunogenicity was evaluated by measuring B epitope-specific immunoglobulins in the serum and the airways by ELISA. Results. The B epitope, in its native form or after substitution of a cysteine by a serine, induced high systemic IgG titers when formulated in the presence of Pam 3 CAG or Pam 2 CAG and administered i.p.. No IgA response was observed in the airways upon injection of candidate vaccines by i.p. route, whatever the B epitope or the adjuvant. However, i.n. vaccination resulted in a significant local production of IgA. Finally, the production of IgG was more rapid when mannose was incorporated. Conclusions. All liposomal candidate vaccines tested induced the production of IgG and/or IgA directed against an immunogenic peptide from P. aeruginosa. Liposomal constructs could be attractive in the vaccination against P. aeruginosa.
Macromolecules, 2010
Cu(I)-catalyzed azide-alkyne [3 þ 2] cycloaddition is used to construct step-by-step covalent pol... more Cu(I)-catalyzed azide-alkyne [3 þ 2] cycloaddition is used to construct step-by-step covalent polymer or polyelectrolyte multilayers. The catalysis involves the formation of a transient, yet rather stable, positively charged Cu(I)/alkyne complex. We demonstrate that the formation of this complex has a strong influence on the multilayer buildup process. It favors, for example, the film buildup between neutral polymer bearing alkyne groups and polyanion bearing azide groups. In contrary, it disfavors the buildup of the same neutral polymer with polycations bearing azide groups. The constructions of other multilayer systems are investigated and discussed in the light of the electrostatic interactions between these positively charged Cu(I)/alkyne complexes and the polyelectrolytes.
Langmuir, 2010
We report the covalent layer-by-layer construction of polyelectrolyte multilayer (PEM) films by u... more We report the covalent layer-by-layer construction of polyelectrolyte multilayer (PEM) films by using an efficient electrochemically triggered Sharpless click reaction. The click reaction is catalyzed by Cu(I) which is generated in situ from Cu(II) (originating from the dissolution of CuSO 4) at the electrode constituting the substrate of the film. The film buildup can be controlled by the application of a mild potential inducing the reduction of Cu(II) to Cu(I) in the absence of any reducing agent or any ligand. The experiments were carried out in an electrochemical quartz crystal microbalance cell which allows both to apply a controlled potential on a gold electrode and to follow the mass deposited on the electrode through the quartz crystal microbalance. Poly(acrylic acid) (PAA) modified with either alkyne (PAA Alk) or azide (PAA Az) functions grafted onto the PAA backbone through ethylene glycol arms were used to build the PEM films. Construction takes place on gold electrodes whose potentials are more negative than a critical value, which lies between-70 and-150 mV vs Ag/AgCl (KCl sat.) reference electrode. The film thickness increment per bilayer appears independent of the applied voltage as long as it is more negative than the critical potential, but it depends upon Cu(II) and polyelectrolyte concentrations in solution and upon the reduction time of Cu(II) during each deposition step. An increase of any of these latter parameters leads to an increase of the mass deposited per layer. For given buildup conditions, the construction levels off after a given number of deposition steps which increases with the Cu(II) concentration and/or the Cu(II) reduction time. A model based on the diffusion of Cu(II) and Cu(I) ions through the film and the dynamics of the polyelectrolyte anchoring on the film, during the reduction period of Cu(II), is proposed to explain the major buildup features.
Langmuir, 2010
Synthesis of functionalized poly(acrylic acid) and bifunctionalized ethylene glycol spacer. All s... more Synthesis of functionalized poly(acrylic acid) and bifunctionalized ethylene glycol spacer. All starting materials were obtained from commercial suppliers and were used without further purification. 1 H NMR and 13 C NMR spectra were recorded on a Bruker Advance DPX300 (300 MHz) or DPX400 (400 MHz) spectrometers. The NMR chemical shifts are reported in ppm relative to tetramethylsilane or tert-butanol (1.24 ppm). Infrared spectra were obtained on a Thermo Electron Corporation Nicolet 380 FT-IR equipped with ATR. Merck RP-18 F254S plates were used for analytical thin layer chromatography. Silica gel 60 (particle: 40-60 μm, Merck, Darmstadt, Germany) was employed for flash chromatography. Low-resolution mass spectroscopy was performed on an Agilent MSD with Agilent 1200 SL HPLC equipped with DAD.
Journal of Liposome Research, 2006
We have developed liposome-based synthetic constructs incorporating peptide epitope(s) (ErbB2 p63... more We have developed liposome-based synthetic constructs incorporating peptide epitope(s) (ErbB2 p63-67 CTL which is overexpressed in many tumors and/or HA 307-319 T-helper) and lipopeptide adjuvants (Pam3CysSerSer, Pam3CysAlaGly) in order to elicit an anti-tumor immune response. The epitopes, derivatized with a linker containing a cysteine residue, were conjugated on preformed vesicles (dia. approximately 100 nm) containing lipopeptides functionalized with thiol reactive groups (maleimide or bromoacetyl). The therapeutic efficacy of these constructs was evaluated on a Balb/c mice tumor model inoculated with syngenic murine renal carcinoma (Renca) cells expressing human ErbB2 (Her2/neu) receptor. A successful therapeutic vaccination was obtained which was antigen specific. Furthermore, it appeared that the nature of the polar head group of the lipopeptide adjuvant and also its type of functionalization influence the efficacy of the construct. In our study, the best results were obtained with formulations containing a Pam3CSS anchor in association with the CTL and Th epitopes. Considering these promising results studies are in progress with a new generation of liposomes that incorporate a neutral lipid--lacking adjuvant properties--that serves as anchor of the peptide epitopes and new adjuvants synthesized in our laboratory, which are screened for their antitumour activity in a therapeutic setting.
Journal of Controlled Release, 2012
Success of synthetic interfering nucleic acids (siRNAs)-based therapy relies almost exclusively o... more Success of synthetic interfering nucleic acids (siRNAs)-based therapy relies almost exclusively on effective, safe and preferably nanometric delivery systems which can be easily prepared, even at high concentrations. We prepared by chemical synthesis various self-assembling polymers to entrap siRNAs into stable polyplexes outside cells but with a disassembly potential upon sensing endosomal acidity. Our results revealed that pyridylthiourea-grafted polyethylenimine (πPΕΙ) followed the above-mentioned principles. It led to above 90% siRNA-mediated gene silencing in vitro on U87 cells at 10 nM siRNA concentration and did not have a hemolytic activity. Assembly of siRNA/πPΕΙ at high concentration was then studied and 4.5% glucose solution, pH 6.0, yielded stable colloidal solutions with sizes slightly below 100 nm for several hours. A single injection of these concentrated siRNA polyplexes into luciferase-expressing human glioblastoma tumors, which were subcutaneously xenografted into nude mice, led to a significant 30% siRNA-mediated luciferase gene silencing 4 days post-injection. Our results altogether substantiate the potential of selfassembling cationic polymers with a pH-sensitive disassembly switch for siRNA delivery in vitro and also in vivo experiments.
Biomaterials, 2011
Synthetic and molecularly defined constructs containing the minimal components to mimic and ampli... more Synthetic and molecularly defined constructs containing the minimal components to mimic and amplify the physiological immune response are able to induce an efficient cytotoxic response. In the current study this approach was applied to the development of highly versatile liposomal constructs to co-deliver peptide epitopes in combination with TLR agonists in order to induce a specific anti-tumor cellular immune response against ErbB2 protein-expressing tumor cells. Liposomes containing ErbB2 p63e71 cytotoxic T lymphocyte (CTL) and HA307-319 T-helper (Th) peptide epitopes associated to innovative synthetic TLR2/ 1 (Pam 3 CAG) or TLR2/6 agonists (Pam 2 CAG and Pam 2 CGD), were injected in mice bearing ErbB2 proteinexpressing tumor cells. Mannosylated ligands were also incorporated into the constructs to target antigenpresenting cells. We showed that the TLR2/6 agonists were more efficient than the TLR2/1 agonists for the eradication of tumors expressing ErbB2 protein. Furthermore, mannose-targeted liposomes displayed higher therapeutic efficiency against tumor allowing treatment with decreased quantities of both TLR ligands and peptide epitopes. Our results validated that antigen-associated mannosylated liposomes combined with efficient TLR ligands are effective vectors for vaccination against tumor. In this study we developed useful tools to evaluate the vaccination efficiency of various adjuvants and/or targeting molecules and their potential synergy.
Angewandte Chemie International Edition, 2011
Bio-MEMS and Medical Microdevices, 2013
ABSTRACT The controlled delivery of drugs and biologicals (proteins, antibodies, DNA and derivati... more ABSTRACT The controlled delivery of drugs and biologicals (proteins, antibodies, DNA and derivatives) is a growing need to take the full benefit of new therapeutic strategies. However these new molecules or biomolecules display solubility issues, or high degradation rates once injected. Therefore, both suitable delivery materials for their encapsulation and protection from the surrounding environment, and smart delivery devices (such as micro-needles or implanted pumps) are necessary to achieve controlled delivery of these precious therapeutic agents. We have developed bio-inspired gel materials, based on lipid nanoparticles which act as reservoirs for lipophilic drugs. The lipid nanoparticles, termed lipidots™, are biocompatible, colloidally stable, non-immunogenic, and obtained from a cheap and simple solvent-free process. The particles can be assembled to form physical or chemical gels, with tunable rheological properties. Physico-chemical studies have been carried out to determine the limits of the stability domains for colloidal and gel formulations (choice of surfactants for nanoparticle surface, and composition ratios of lipids, surfactants and co-surfactants). In particular, it is demonstrated that lipid nanoparticles keep their integrity in the gels. Gels of lipidots™ could therefore constitute biocompatible materials for the efficient encapsulation and tuned delivery of lipophilic drugs and biomolecules.
Surface and Coatings Technology, 2013
ABSTRACT The deposition of organic thin films with accurate thickness and tailored functionality ... more ABSTRACT The deposition of organic thin films with accurate thickness and tailored functionality is an important step towards the development of gas sensors with high selectivity. In fact, thin films able to selectively interact with gas-phase analytes are central building blocks for the new generation of extremely sensitive sensors. In this contribution, we report on the molecular layer deposition of alucone thin films enclosing tertiary amine functions in their bulk. The sequential exposure of substrates to the metal precursor, trimethylaluminum, and to the organic linker triethanolamine was investigated for the growth of alucone thin films that contain tertiary amine groups. The systematic monitoring of the growth process was performed gravimetrically using a quartz crystal microbalance and by the analysis of the exhaust gas with mass spectrometry. The obtained films were analyzed by SIMS, XPS, FTIR and ellipsometry to perform elemental, chemical and optical characterization. A saturated deposition process was demonstrated and used for the growth of thin films that include nitrogen in their bulk. The obtained films exhibit a density of 2.35 g/cm3 and they dissolve readily in ultrasonic bath of acetone, but not in water.
Plasma Processes and Polymers, 2010
Skip to Main Content. ...
Pharmaceutical Research, 2009
To design and evaluate liposomal constructs capable of inducing a potent systemic and airway humo... more To design and evaluate liposomal constructs capable of inducing a potent systemic and airway humoral response to Pseudomonas aeruginosa Liposomes contained a peptide derived from P. aeruginosa pilin protein as B epitope, a peptide derived from Influenza hemagglutinin protein as Th epitope, the TLR agonist Pam3CAG or Pam2CAG as adjuvant, and a mannosylated lipid as dendritic cell targeting agent. These constructions were administered to mice intraperitoneally (i.p.) or intranasally (i.n.). Their immunogenicity was evaluated by measuring B epitope-specific immunoglobulins in the serum and the airways by ELISA. The B epitope, in its native form or after substitution of a cysteine by a serine, induced high systemic IgG titers when formulated in the presence of Pam3CAG or Pam2CAG and administered i.p.. No IgA response was observed in the airways upon injection of candidate vaccines by i.p. route, whatever the B epitope or the adjuvant. However, i.n. vaccination resulted in a significant local production of IgA. Finally, the production of IgG was more rapid when mannose was incorporated. All liposomal candidate vaccines tested induced the production of IgG and/or IgA directed against an immunogenic peptide from P. aeruginosa. Liposomal constructs could be attractive in the vaccination against P. aeruginosa.
Uploads
Papers by Jean-Sébastien Thomann