Identification and quantification of concentration-dependent biomarkers in MCF-7/BOS cells exposed to 17β-estradiol by 2-D DIGE and label-free proteomics

in Journal of Proteomics (2012), in press

This paper reports the identification of biomarkers resulting from the exposure of MCF-7/BOS cells to 17β-estradiol (E2). The biomarkers were identified using 2 independent and complementary techniques, 2 ... [more ▼]

This paper reports the identification of biomarkers resulting from the exposure of MCF-7/BOS cells to 17β-estradiol (E2). The biomarkers were identified using 2 independent and complementary techniques, 2-D DIGE / MALDI-TOF peptide mass fingerprint, and 2-D UPLC-ESI MS/MS. These markers form a preliminary molecular signature that can be used when testing the estrogenic activity of xenobiotics, either pure or in mixtures. [less ▲]

Stealth macromolecular platforms for the design of MRI blood pool contrast agents

in Polymer Chemistry (2011), 2(10), 2316-2327

Stealth macromolecular platforms bearing alkyne groups and poly(ethylene oxide) brushes were synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. The anchoring of Gd3 ... [more ▼]

Stealth macromolecular platforms bearing alkyne groups and poly(ethylene oxide) brushes were synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. The anchoring of Gd3+-chelates bearing an azide group was then carried out by the Huisgen 1,3-dipolar cycloaddition (“click”) reaction in mild conditions, leading to macrocontrast agents for MRI applications. The gadolinium complex is hidden in the PEO shell that renders the macrocontrast agents free of any cytotoxicity and stealth to proteins of the immune system. Relaxometry measurements have evidenced an improved relaxivity of the macrocontrast agent compared to ungrafted gadolinium chelate. Moreover, this relaxivity is further enhanced when the spacer length between the Gd3+-chelate and the polymer backbone is shorter, as the result of its decreased tumbling rate. These novel products are therefore promising candidates for MRI applications. [less ▲]

Methylmercury and selenium in vitro effects on harbor seal (Phoca vitulina) lymphocytes : a multidisciplinary approach

Poster (2010, May 26)

Methylmercury (MeHg) bioaccumulates along the food web, leading to the highest levels in tissues of predatory species. It constitutes the predominant form present in the blood of marine mammals. The blood ... [more ▼]

Methylmercury (MeHg) bioaccumulates along the food web, leading to the highest levels in tissues of predatory species. It constitutes the predominant form present in the blood of marine mammals. The blood cells, including the immune cells, are therefore exposed to the toxic properties of that chemical. Nevertheless, selenium (Se) is an essential element absorbed concomitantly to MeHg which seems to modulate this toxicity. The goal of this study is to evaluate the immunotoxicity of MeHg on the harbor seal (Phoca vitulina) T lymphocytes, highly important in the adaptive immune response, and to investigate the modulating effect of Se on that toxicity. In parallel, the concentrations of MeHg, total mercury (T-Hg) and Se are determined in free-ranging harbour seal blood in order to follow their contamination levels. The T lymphocytes were isolated from the whole blood, exposed to various MeHg and Se concentrations and the exposure effects were estimated by functional tests including the evaluation of viability, proliferation, metabolic activity, DNA and protein synthesis, and by morphological analysis by transmission electron microscopy. The mean T-Hg concentration was 172 ± 143 µg/l of whole blood. The T lymphocytes cultures in vitro displayed a decreasing number of viable cells with increasing concentrations of MeHg, and numerous ultrastructural defects. The cells exposed to MeHg notably displayed distortion of the plasmic membrane, nucleus fragmentations, chromatin compaction, swelling mitochondrias and cytoplasmic vacuolisations. Those results highlighted various immunotoxic effects of MeHg, both at the functional and ultrastructural levels. The antagonistic role of Se on MeHg immunotoxicity is discussed. [less ▲]

Study of methylmercury and selenium effects on harbor seal (Phoca vitulina) T lymphocytes in vitro

Poster (2009, November 27)

Development of a strategy to study toxicodynamic of pollutants in spawning sea turtles

Poster (2009, February)

Evaluation of the long-term barrier effect of commercial resorbable guided tissue regenerative membranes : an in vitro study using human gingival fibroblasts

Poster (2009)

Introduction The first part of the study devoted to guided tissue regenerative membranes was focused on a better understanding of the physicochemical and mechanical properties of commercial materials. The ... [more ▼]

Introduction The first part of the study devoted to guided tissue regenerative membranes was focused on a better understanding of the physicochemical and mechanical properties of commercial materials. The second objective of our study was to develop an in vitro device able to measure the long-term barrier effect of resorbable membranes. After the development of this new device, experiments were realized to characterize the long-term behaviour of commercially membranes with human gingival fibroblasts (HGF). Materials and methods The use of human gingival fibroblastic cells was chosen to get closer to biological conditions. Some gingival explants were removed in young and non-smoking healthy patients. From these explants, fibroblastic cells were isolated and cultivated. These cells will be able to be used between the third and the sixth passage. Resorbable membranes were chosen because they don’t require a second surgical operation. There are made of polyesters or collagen. A system based on inserts was developed in order to follow the degradation of membranes and the migration of cells across the material. The membrane was cut into 8 mm diameter punches and set in the bottom of the system. Once the whole was put together, it is laced into a 12 wells plate culture. First, the plates were put in an incubator at 37°C, during times ranging from 24 hours to several months. The barrier effect was then measured to reflect the gradual increase of permeability of each membrane. For this purpose, HGF were seeded on the different samples. The top of the bottle and the bottom of the well were then filled with culture medium. Non degradable synthetic Bioflex membranes were chosen as control samples which don't let pass cells (porosity : 0,4 µm). After 48 hours of incubation in the presence of cells, pictures of cells on membranes and in the bottom of wells were taken with an optic microscope. Viability tests (MTS) were then realized on membranes to evaluate cells proliferation and in the bottom of wells to measure barrier effect. Finally, the morphology of cells on selected membranes was characterized by Scanning Electron Microscopy. Conclusion Proliferation results correspond to data published by several authors. Furthermore, the barrier effect times found in the present study are similar to barrier effect times demonstrated in in vivo studies and announced by manufacturers. In conclusion, the finalized system is adapted to the analysis of long-term barrier effect of commercial GTR membranes. This system will be tested with synthetic bioresorbable membranes made of copolymers. [less ▲]

Etude de l’effet du méthylmercure et du sélénium sur les lymphocytes de phoque commun (Phoca vitulina) par analyses fonctionnelles, morphologiques et protéomiques

Poster (2008, December 12)

Development of a strategy to study toxicodynamic of pollutants in spawning sea turtles from the French West Indies

Poster (2008, October)

Sea turtles including the green turtle Chelonia mydas and the hawksbill turtle Eretmochelys imbricata are critically endangered species, facing different factors as marine pollution. There is a blatant ... [more ▼]

Sea turtles including the green turtle Chelonia mydas and the hawksbill turtle Eretmochelys imbricata are critically endangered species, facing different factors as marine pollution. There is a blatant lack of data dealing with toxicants such as metals and persistent organic pollutants (POPs) in sea turtles. We developed a strategy to apprehend levels, effects and transfer to offspring of several pollutants in sea turtles. Sampling of blood, subcutaneous tissue and eggs of 15 gravid C. mydas and E. imbricata was carried out between July and September 2008 in Martinique (Diamant’s beach) and Guadeloupe (Petite Terre and Marie-Galante). Blood was collected from the dorso-cervical sinus and subcutaneous tissue was sampled in shoulder of the spawning females using a 5 mm biopsy punch (Kai Europe GmbH, Germany). Total blood and serum were successfully taken for metal, POP and biomarker investigations. T-mercury was analyzed by DMA milestones while PCBs, DDT and chlordecone were analyzed by EDC Ni63 high performance gas chromatography HPLC. Samples of serum were analyzed for vitamins (A and E) by HPLC and for thyroid hormones (triiodothyronine and thyroxine) by radioimmunoassay. In parallel to this field study, a cell model using 3T3-L1 cell line was built up to test in vitro effects of PCBs and mercury as well as the relationship between in vitro exposure and fat mobilization. Preliminary results showed a dose-response relationship between increased Aroclor 1234 and 1252 concentrations (0.5 ppb, 1 ppb and 1.5 ppb) and adipocyte mortality (Nucleocounter). The strategy we propose here will bring further insights on levels and potential impact of pollutants on female sea turtles and their offspring. [less ▲]

Exposition et effets du méthylmercure chez le phoque commun (Phoca vitulina)

Speech (2008)

Effects of methylmercury and selenium on harbor seal (Phoca vitulina) lymphocytes by functional, morphologic and proteomic analysis

Speech (2008)