Dissertations / Theses on the topic 'Criblages'
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Autour, Alexis. "Amélioration et criblages de propriétés d'ARN aptamères fluorogènes en systèmes microfluidiques." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAJ057.
RNA is a key molecule in gene expression and its regulation. Therefore, being able to monitor RNA through live-cell imaging would represent an important step toward a better understanding of gene expression regulation. RNA-based fluorogenic modules are extremely promising tools to reach this goal. To this end, two light-up RNA aptamers (Spinach and Mango) display attractive properties but they suffer from a limited brightness. Since previous work in the group demonstrated the possibility to evolve RNA using microfluidic-assisted in vitro compartmentalization (µIVC), this technology appeared to be well suited to improve light-up aptamers properties by an evolution strategy. Therefore, the µIVC procedure was adapted to fluorogenic RNA aptamers to improve their properties (especially the brightness). Finally, using µIVC in tandem with high-throughput sequencing (NGS) allowed further developing the technology into a more integrated and semi-automatized approach in which RNAs and biosensors are selected by µIVC screening and the best variants identified by a bioinformatics process upon NGS analysis. To summarize, this thesis allowed establishing robust µIVC screening workflows for the discovery of novel efficient light-up RNA aptamers as well as metabolites biosensors
Giroux, Valentin. "Criblages systématiques de nouvelles cibles thérapeutiques dans le traitement du cancer pancréatique humain." Aix-Marseille 2, 2008. http://theses.univ-amu.fr.lama.univ-amu.fr/2008AIX22082.pdf.
Pancreatic cancer is a disease with a very bleak prognosis despite important therapeutic efforts. The best chemotherapeutic agent, gemcitabine, is making a modest improvement of survival and has a very low response rate. The failure of current antitumoral strategies means that new targets possibilities must be explored. The cellular stress comprises of all events that disrupt cell homeostasis. The cell survival in response to stress involves activation of genes. The p8 protein is a stress protein induced by several stimuli and could therefore have a role in the resistance of pancreatic cancer. Here, we have demonstrated that the p8 protein is involved in resistance to gemcitabine in human pancreatic cancer cells. We have also described one of the mechanisms by which p8 regulates apoptosis by studying its interaction with the prothymosin α. There are more than 500 protein kinases in human cells which represent, by virtue of their central role in cell signaling, potential targets for the treatment of pancreatic cancer. Using a systematic screening of the human kinome, we obtained a catalogue of kinases involved in the survival of human pancreatic cancer cells. After selecting several candidates in this catalogue, we have demonstrated that their combined inhibition with siRNAs improves the induction of apoptosis in human pancreatic cancer cells in vitro and in intrapancreatic xenografts in a mouse model in vivo. This work opens up interesting perspectives for the use of new therapeutic targets for the treatment of pancreatic cancer
Colin, Boris. "Développement de méthodes de criblages et d'analyses en parallèle appliquées aux polymères modifiés silanes." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S145.
The aim of this work is to discover new catalytic systems to replace organotin compounds. The strategy used on our laboratory exploits tools of high throughput experiments to test a large number of catalysts in the same time in order to discover new catalytic systems more quickly
Macovei, Cristian-Paul. "Identification de catalyseurs à l'aide de criblages à haut débit basés sur des techniques immunoenzymatiques." Phd thesis, Université Paris Sud - Paris XI, 2008. http://tel.archives-ouvertes.fr/tel-00447202.
Husson, Guillaume. "Développement de méthodes de criblages et en prallèle pour catalyse hétérogène de polymérisation d'oléfines gazeuses." Rennes 1, 2007. http://www.theses.fr/2010REN1S158.
In the first research part, two libraries of ligands have been synthesized in parallel and evaluated in olefin polymerization: bridged ligands for metallocenes and deprotonated carbonylamino fulvene ligands. This work led to the discovery of active systems in homogeneous and heterogeneous catalysis of polymerization. The second part is the development of new high-thoughput methods for heterogeneous catalysis of olefins polymerization. Sealed bags, where the supported catalysts are introduced and the polymer is formed, produce in parallel various polymers from several different catalytic systems. The multi-spot plates method allows a quick and simple evaluation of catalysts in gas-phase polymerization. Finally, the last part is the development of a new technique for viscosimetric analysis with optical tweezers applied to poly(sodium 4-styrene sulfonate) in water. Comparisons between rheology governed by empirical laws and microrheology have been conducted to validate this analysis method
Serve, Olivier. "Méthodologies de criblages d'interactions protéines-ligands par RMN : inhibitions de la Glms et de Bcl-xL." Paris 11, 2008. http://www.theses.fr/2008PA112134.
The versatility of Nuclear Magnetic Resonance (NMR) allows several applications in various domains. This versatility makes it a tool of prime importance in the field of therapeutic treatments research. It allows the determination of the structure and the dynamic of the interacting molecules. We used NMR on two proteins involved in diverse pathologies : Bcl-xL, partially responsible for the apoptosis deficiency for certain cancers, and the Glms, known to give complications to people affected with type II diabetes and target in the anti-microbial fight. The goal was to enhance our understanding of the interactions between those proteins and new molecules able to inhibit their activities. Those molecules are either extract from plants (Bcl-xL study), or synthesized (Glms study). Our results allowed to give orientations about the enhancements of the therapeutic effects of the studied molecules
Lienhart, Yann. "Analyse et exploitation de données de criblages de réactions chimiques pour la recherche de voies de synthèse." Strasbourg, 2011. http://www.theses.fr/2011STRA6223.
Chemistry databases are centered on chemicals and their reaction data is extracted from scientific literature. They are usually given in non-standardized conditions and in general nothing is available about reactions that did not occur or exhibit a low yield. Thus, it can be difficult to compare reactions and chemical transformations because of the specific experimental conditions and the missing data. This thesis has been funded by NovAlix (CIFRE), a company specialized in organic chemistry synthesis and structural biology. In order to explore the chemical space and improve the chemical synthesis process, two high-throughput reactions screening methods using gas chromatography and mass spectrometry have been set up in NovAlix. The Magellan information system developed during this thesis use a chemical reaction-centric database and is built on Java Enterprise Edition open-source technologies. It allows collecting high-throughput data from mass spectrometry and gas chromatography experimentations realized in standardized conditions. Then, the Magellan application enables the chemist to read and store experimental results, provides tools to help data analysis and query the collected data via a rich-client user interface
Navarri, Marion. "Métabolites secondaires de champignons de sédiments marins profonds : criblages génétique et fonctionnel et caractérisation structurale de molécules antimicrobiennes." Thesis, Brest, 2016. http://www.theses.fr/2016BRES0127/document.
The spreading of antimicrobial resistant microorganisms jeopardizes global health caresystem. To counteract this threat the renewal of antibiotic molecules is a global priority. Antibioticcompounds are mainly originated from microorganisms, so microorganisms and their secondarymetabolites received an increasing interest. The search for new natural antimicrobial compoundsfrom microorganisms gained untapped ecosystems as marine biosphere.We investigated the antimicrobial properties of a fungal collection. The 183 fungal isolateswere collected from deep subseafloor sediment and isolated between 4 and 1,884 meters belowthe seafloor. Secondary metabolites production potential was studied for all isolates in thecollection by screening genes coding PolyKetide Synthase (PKS), Non-Ribosomal Peptide Synthetase(NRPS), TerPene Synthase (TPS) and hybrid PKS-NRPS. After isolates dereplication according to theirMSP-PCR fingerprinting, an antimicrobial screening was performed for 110 isolates, highlighting ahigh proportion of filamentous fungi with antimicrobial properties (32%).After extraction and bio-guided fractionation bioactive metabolites isolated from 3 strains,were characterized in a structural and functional manner: O. griseum UBOCC-A-114129 producedfuscin, dihydrofuscin, secofuscin and dihydrosecofuscine, P. bialowiezense UBOCC-A-114097synthetized mycophenolic acid and Penicillium sp. UBOCC-A-114109 produced rugulosin.In the meantime, LC-HRMS analysis, performed on fungal extracts, showed a great proportionof metabolites not detected in interrogated databases. So, deep subseafloor fungi, represent anuntapped reservoir of original structures to explore
Giganti, David. "Etudes structurales et criblages in silico de chimiothèques sur des cibles thérapeutiques de plasmodium falciparum et mycobacterium tuberculosis." Paris 7, 2008. http://www.theses.fr/2008PA077243.
Nowadays, the identification of leads from a therapeutic target becomes a classic pipeline for drug discovery. In silico virtual screening approaches, based on this target structure allow the enrichment of a large compounds databank in a significantly reduced subset. This selection involves a docking procedure, for each compound, which predicts their binding mode to the target and their affinity, in order to classify them. Finally, the experimental validation of these relevant compounds is a performing substitute to a costly High-Throughput Screening. On two collaborative projects at Institut Pasteur, we apply a structure-based screening to help antimalarial and antituberculous leads finding. The therapeutic target SUB2 is an essential protease in the erythrocyte invasion. We successfully manage to identify compounds able to inhibit its activity, in vitro. Since no experimental structure of SUB2 is available, the screening required a prior comparative modeling of the P. Falciparum on homologous bacterial proteins. The second project concerna PimA, a fundamental glycosyltransférase for the construction of the mycobacteria cell wall. In contract to SUB2, the virtual screening process take advantage of the recent structure frorn PimA crystal and lead the determination of promising inhibitors. For both projects, we also initiate a optimization campaign based on the understanding of the inhibitory mecanism of the leads in the aim to design their chemical structure. Improvement of their efficiency is indeed necessary at this point of the preclinical step. We also study the non specific and superficial association of these enzymes to the plasmatic membrane
Maréchal, Xavier. "Développement d'inhibiteurs du protéasome à visée pharmacologique : élaboration rationnelle, criblages de collections de molécules et évaluation biologique sur des modèles cellulaires." Paris 6, 2011. http://www.theses.fr/2011PA066351.
Maury, Yves. "Utilisation de cellules souches pluripotentes humaines pour le développement de criblages phénotypiques dans le cadre de la dystrophie myotonique de type 1 et l'amyotrophie spinale infantile." Thesis, Evry-Val d'Essonne, 2013. http://www.theses.fr/2013EVRY0019/document.
For only few years, Human pluripotent stem cells (PSC) have become wide spread models in order to study and decipher cellular or molecular mechanims involved in monogenic diseases, but also for the development of large scale screening strategies allowing the identification of new therapeutics among thousands of chemicals. Mythesis research aimed at the development of such strategies, miniaturizing and automating PSC biology within the framework of two monogenic diseases, namely spinal muscular atrophy (SMA) and myotonic dystrophy type 1 (DM1).Basically, PSC based screening programs are generally built around three main steps which are the access to a stem cell model, the identification of a relevant cell type and lastly the screening campaign. There is actually two main ways to generate human PSC. Firstly, human embryonic stem cells (hES) can be derived from the inner cell mass of blastocyte through a pre-implantation diagnosis and secondly, induced pluripotent stem cells (iPS) can be generated after somatic cell reprogramming in vitro. A part of my work has consisted in the generation of hiPS cellular models for SMA by reprogramming fibroplasts that carried SMN1 gene deletion, followed bay the characterization of several dozen of independant clones with high throughput. Then an optimization process of the protocol for the generation of Motoneuron from PSC has been done multiplying experimental conditions. This finally allowed the description of a fast and efficient protocol to generate the most affected cell type in SMA. Finally, DM1 mutated hES were uded for the screening of 12.000 compounds among which a chemical family has been identified to rescue DM1 typical splicing and myogenesis defects
Muller, Pascal. "Criblage virtuel inverse : validation et applications." Strasbourg 1, 2006. http://www.theses.fr/2006STR13137.
The conception of bioactive molecules uses more and more in silico methods. Discovering which ligands, out of a large library, are likely to bind to a protein of interest is slowly turning into routine computational chemistry. Surprisingly, the opposite question is still an issue. Given a known ligand, is it possible to recover its most likely target(s)? Answering this question using the above mentioned docking approach implies the development of a collection of protein active sites. As a database of choice to develop the inverse virtual screening (IVS) procedure, we have chosen the Protein Data Bank. We extracted from the PDB a target library, the sc-PDB. It is a collection of three-dimensional structures of active sites. I contributed to validate the IVS procedure: it is able to find known targets of ligands. In the process of sc-PDB update, I developed an algorithm able to accurately identify protein-ligand complex. I used IVS procedure to discover targets for new molecules: chemists wanted to know if the chemical space of their combinatorial library matches pharmaceutical targets. Five targets were selected in silico, and two targets were validated in vitro. The sc-PDB library and IVS procedure are powerful tools, and the simplicity of the approach makes it particularly attractive for prioritizing a few targets for experimental validation, and is therefore a good complement to experimental target identification strategies
Paul, Nicodème. "Développement de nouvelles applications en criblage virtuel." Strasbourg 1, 2003. http://www.theses.fr/2003STR13193.
Based on molecular docking, virtual screening or in silico screening becomes of increasing interest in the pharmaceutical industry. In this study, we propose ConsDock a consensus docking program that takes advantage of three widely used docking tools Dock, Gold and FlexX. ConsDock significantly outperforms single docking with respect to the docking accuracy of the top-ranked pose. Then, for inverse screening purpose, we develop a protein database based on the Protein data Bank (sc-PDB). This database has been used to recover target of known ligands by using an in-house inverse screening process based on Gold. At last, as we were interested in developing activated models of G Protein-Coupled Receptors or GPCRs, we present a simulation process of ligand-based GPCR folding. The simulation is performed by genetic algorithms. By using a GPCR and a ligand, the algorithm tries to find stable conformations of GPCR by rotating and translating helices. Movement is performed according experimental observations. We tested the method on the X-ray structure of rhodopsin complexed with the cis-retinal. We got some good results when used specific genetic operators for a sufficient number of generations
Varenne, Fanny. "Développements analytiques pour le criblage d'interactions lanthanides/ligands." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00763230.
Bélanger, Audrey. "Criblage pharmacologique de nouvelles molécules à caractère antipsoriasique." Master's thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27696.
Psoriasis is a chronic skin disease characterized by erythematous plaques with loosely adherent silvery-white scales. Psoriatic patients have at their disposal several treatments that control the disease however, no cure has been found yet., Current treatments for psoriasis are associated with toxicological problems and short- and long-term adverse effects. Hence, it is imperative to discover new therapeutic molecules in order to significantly improve the quality of life of psoriatic patients. Tissue engineering of skin is used to deepen our knowledge in dermatology and to investigate on new topical therapeutics for the cosmeceutical or pharmaceutical fields. Three-dimensional (3D) cell culture recapitulates normal and pathological tissue architectures that provide physiologically relevant models to study normal development or diseases of the tissue. The self-assembly method developed at LOEX allows to produce healthy or psoriatic bilamellar skin substitutes. The aim of this project was to demonstrate, using pharmacological screening, the antipsoriatic potential of a range of compounds derived from the plant biomass of the boreal forest. Toxicity assays were used to screen 39 molecules at different concentrations, and a choice of 9 molecules inhibiting the keratinocyte growth at low concentrations was made to pursue this project. Among these 9 molecules, all tested on healthy and psoriatic 3D skin substitutes, 4 of them have shown promising therapeutic properties for the normalization of keratinocyte proliferation and differentiation; these 4 molecules upregulate the expression of several proteins involved in cellular differentiation (involucrin, filaggrin, loricrin) or cellular proliferation (Ki-67). Histological analyses of psoriatic skin substitutes treated with these 4 molecules showed a significant decrease of the epidermis thickness. Thereby, these innovative molecules with a polyphenolic structure could possibly be used as an effective treatment of psoriasis.
Mahtal, Nassim. "Criblage de molécules stimulant l'immunité innée et acquise." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS253.
Immune system boosters could have many applications in public health: fighting antibiotics resistance, epidemics, protection of health care staff and populations during health crisis or biological warfare. Currently, the rare efficient immune stimulants are costly and dangerous; hence, they are earmarked to severe and targeted pathologies such as cancers, aplasia, or chronic viral infections. The small G protein Rac1 was identified as a potential therapeutic target. Once activated by various pathogens, it controls inflammation and host defenses establishment. CNF1 is a bacterial toxin that strongly activating Rac1, leading to its proteasomal degradation. Maintaining an activated Rac1 pool could enhance immune defenses. By using CNF1 as a tool to reduce it, a cellular bioassay was developed and optimized to screen 17 680 compounds. Through various filters, a group of molecules was identified to prevent CNF1-mediated Rac1 depletion. Unexpectedly, most of them seems to possess anti-inflammatory properties, down-regulating cytokines production from stimulated cells. The therapeutic potential of such compounds must be now evaluated. In parallel, two other molecules show a broad-spectrum anti-toxins protection (CNF1, diphtheria toxin, Shiga toxin, toxin B from C. difficile). Their unknown mode of action may allow the treatment of various infections
Guillemain, Hélène. "Evaluation et application de méthodes de criblage in silico." Phd thesis, Conservatoire national des arts et metiers - CNAM, 2012. http://tel.archives-ouvertes.fr/tel-00814270.
Harfouche, Lina. "Criblage de l'état solide chiral et diagrammes de phases." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR007.
Many active pharmaceutical ingredients are chiral compounds. The two enantiomers of the corresponding molecules exhibit identical chemical and physical properties, but the desired biological activity is often provided by only one enantiomer. The strict regulations forced the pharmaceutical industry to develop new ways to produce pure enantiomers. Among separation methods, Preferential Crystallization (PC), is a technique with relatively high productivity and low cost. It consists of the out-of-equilibrium alternative crystallization of both enantiomers. It is thought that the application of PC is only possible when the enantiomers crystallize as a conglomerate, i.e. a physical mixture of homochiral particles. Yet, only ca 5-10% of the racemic species crystallize as a conglomerate, which strongly limits the applicability of PC. The work investigates how to perform PC in the remaining 90-95% of cases, for enantiomers crystallizing as racemic compounds, i.e. a 1:1 stoichiometric compound made with both enantiomers. Following an adequate screening procedure based on physico chemical and molecular considerations, one racemic chiral molecule was selected as model compound, namely “proxyphylline” (PXL). After the construction of the binary phase diagram between the enantiomer of PXL reveals a rich polymorphism (double polymorphism for enantiomer and racemic), PXL has been resolved by two approaches: (a) via an unforeseen metastable conglomerate, by inhibiting the spontaneous crystallization and growth of the undesired forms and by achieving a wide metastable zone width due to the selection of a suitable solvent. The obtained results extend the applicability of PC to the racemic forming system with specific thermodynamic (melting temperature) and kinetic (wide metastability) characteristics. (b) via a stable monohydrated conglomerate prepared by cocrystallization with salicylic acid. It was resolved by PC from a water/ethanol mixture with high productivity. This may be the first report of PC applied to such a cocrystal system
Lerouxel, Olivier. "Criblage de mutants d’Arabidopsis et caractérisation du mutant dgl1." Rouen, 2004. http://www.theses.fr/2004ROUES033.
The plant cell wall is a highly organized matrix, mainly composed of polysaccharides, that is determinant for plant morphology and development. Strikingly little is known about the enzymes that control cell wall biosynthesis and deposition. The characterization of Arabidopsis cell wall mutants is one of the more promising approaches to investigate the synthesis, transport and assembly of cell wall polysaccharides. However, the identification of new cell wall mutants from public collections is a major bottleneck. In this context, the aim of the PhD thesis was first to design new biochemical screening methodologies to detect Arabidopsis cell mutants and second to apply these methodologies to the selection of new mutants. We demonstrated that the quantification by gas chromatography of the monosaccharide contents of Arabidopsis seedling cell wall give reproducible and informative information allowing the selection of plants exhibiting cell wall alteration. Moreover, an innovative enzymatic fingerprinting strategy was developed and validated on previously characterized xyloglucan mutants. In this screening methodology, cell wall material has been treated by an endoglucanase and the generated fragments have been identified by chromatography, electrophoresis or MALDI-TOF mass spectrometry. These strategies have been used for the screening of new cell wall mutants. A mutant called defective glycosylation1-1 (dgl1-1) was identified in Arabidopsis based on a growth defect of the dark-grown hypocotyl and an abnormal composition of the non-cellulosic cell wall polysaccharides. Dgl1-1 is altered in a protein ortholog of human OST48 or yeast WBP1, an essential protein subunit of the oligosaccharyltransferase complex that is responsible for the transfer in the ER of the N-linked glycan precursor onto Asn residues of candidate proteins. Consistent with the known function of the OST complex in eukaryotes, the dgl1-1 mutation led to a reduced N-linked glycosylation of the ER-resident protein disulfide isomerase (PDI). A second more severe allele (dgl1-2) was embryo-lethal. Microscopic analysis of dgl1-1 revealed severe developmental defects including a strongly reduced cell elongation and, collapse and differentiation defects of cells in the central cylinder. These defects were accompanied by changes in the non-cellulosic polysaccharide composition, including the accumulation of ectopic callose. Interestingly, in contrast to other dwarf mutants that are altered in the early steps of the N-glycan processing, dgl1-1 did not exhibit a cellulose deficiency. Together these results confirm the role of DGL1 in N-linked glycosylation, cell growth and differentiation in plants
Barre, Françcois-Xavier. "Analyse et criblage d'oligonucléotides antigènes dirigés contre le VIH." Châtenay-Malabry, Ecole centrale de Paris, 1998. http://www.theses.fr/1998ECAP0601.
Bui, The Quang. "Criblage virtuel sur grille de composés isolés au Vietnam." Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22583/document.
Virtual Screening (VS) is a computational technique used in the drug discovery process to select the most promising candidate drugs for in vitro testing from millions of chemical compounds. This method can offer an efficient alternative to reduce the cost of drug discovery and platform. The Natural Products Chemistry Institute of the Academy of Sciences of Vietnam (INPC) collects samples from local biodiversity and determines the 3D structure of single molecules. Their challenge is to set up a virtual screening platform on grid computing for their chemists to process their data. However, as the number of users who might have a wide range of virtual screening applications (in terms of the number of tasks and execution time) increases with limited available computing resources, it becomes crucial to devise an effective scheduling policy that can ensure a certain degree of fairness, user satisfaction and overall system throughput. In this context, the thesis focuses on an effective scheduling policy for the virtual screening workflow where multiple users with varying numbers of tasks are actively sharing a common system infrastructure. We have researched in theory and proposed some candidate policies. With the simulation results and the experimentation results in real system, we proposed the best policy for the fairness between users, which can be applied to INPC virtual screening platform
Playe, Benoit. "Méthodes d'apprentissage statistique pour le criblage virtuel de médicament." Thesis, Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLEM010/document.
The rational drug discovery process has limited success despite all the advances in understanding diseases, and technological breakthroughs. Indeed, the process of drug development is currently estimated to require about 1.8 billion US dollars over about 13 years on average. Computational approaches are promising ways to facilitate the tedious task of drug discovery. We focus in this thesis on statistical approaches which virtually screen a large set of compounds against a large set of proteins, which can help to identify drug candidates for known therapeutic targets, anticipate potential side effects or to suggest new therapeutic indications of known drugs. This thesis is conceived following two lines of approaches to perform drug virtual screening : data-blinded feature-based approaches (in which molecules and proteins are numerically described based on experts' knowledge), and data-driven feature-based approaches (in which compounds and proteins numerical descriptors are learned automatically from the chemical graph and the protein sequence). We discuss these approaches, and also propose applications of virtual screening to guide the drug discovery process
Aymard, Chloé. "Nouvelles méthodes électrochimiques pour le criblage d’inhibiteurs de transcétolases." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1212/document.
This thesis focuses on the development of a new electrochemical method allowing the high throughputscreening of enzyme inhibitors. For this purpose, a target enzyme has been selected for its therapeutic interest,transketolase (TK): this enzyme is involved in many diseases (cancer, neurodegenerative diseases, diabetes ...) and inthe survival of pathogenic parasites. To measure TK activity, two reporter systems have been developed by usingelectrochemical plates, composed of 96 independent electrodes.The first one is based on a bienzymatic system, requiring the use of an auxiliary enzyme, galactose oxidase(GAOx), in its soluble form or immobilized in laponite. This enzyme is able to oxidize TK products and producehydrogen peroxide. The 96-well format allowed to quickly optimize the electrochemical detection of oxidase activityby intermittent pulse amperometry (IPA) of oxidase activity and only 10 minutes are required to perform 96simultaneous measurements. In parallel, in order to harness the 96-well electrochemical system, this detection ofoxidase activity was also carried out in 10 minutes using electrochemiluminescence. This method is more sensitiveand less variable than IPA but is limited to the use of soluble enzymes. However, the reaction conditions are notoptimal for the bienzymatic system (TK-GAOx): long incubation times are required and are poorly adapted for thescreening of TK inhibitors.A second reporter system no longer requiring an auxiliary enzyme and involving only one TK substrate hasbeen optimized. This system relies on the oxidation by ferricyanide of the reactional intermediate resulted of thebinding of the cofactor (thiamine pyrophosphate) and the substrate. This method allows to measure 96 TK activitiesin only 7 minutes and was easily used to screen an in-house chemical library. The screening of 1360 molecules leadto the identification of a new TK inhibitor with an IC50 of 63 μM. This electrochemical system was also used todetermine the mechanism of inhibition (partial non-competitive mechanism) and the associated inhibition constant(3.4 μM). These results are innovative in the field of electrochemistry and offer a wide range of applications forenzymatic activity screening or the screening of enzymes inhibitors
Meslamani, Jamel Eddine. "Développement de nouvelles méthodes de criblage in silico en chémogénomique." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00763448.
Kolodych, Sergii. "Recherche de nouvelles réactions de couplage par criblage immuno-enzymatique." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112145.
Discovery of new reactions is one of the fundamental goals in organic chemistry. In addition to the traditional approach to reaction discovery, consisting in designing a reaction on the basis of known chemical properties of reagents, new approaches based on the screening of random combinations of reactive functions and catalysts have been recently developed. The main prerequisite of this strategy is an analytical tool allowing screening of a big number of reactions per day and identifying combinations leading to the formation of unanticipated products. In the work presented herein a high-throughput immunoassay screening has been used for the discovery of new coupling reactions. In the first part of this work a screening of 2688 combinations of randomly chosen reactive functions and catalysts was carried out. This screening led to the discovery of two copper-promoted coupling reactions: a reaction between thioureas and phenols leading to the formation of isoureas through desulfurization; and a reaction between N-hydroxythioureas and alkynes leading to the formation of thiazole-2-imines. In the second part of the work a screening of 2816 combinations of rationally designed chemical functions and catalysts was carried out. This screening was focused on the discovery of catalytic [3+2] cycloadditions that comply with the standards of “click” chemistry. In this study, the use of immunoassay screening was extended to optimize new reactions and to evaluate their kinetics, chemoselectivity and biocompatibility. Therefore, around 3000 complementary tests were carried out on the hits, identified in the primary screening. This allowed the discovery of 3 new coupling reactions and one new “click” reaction: a copper-catalyzed sydnone-alkyne cycloaddition (CuSAC). The last part of the work was focused on detailed studies of the CuSAC reaction. Identification of the structure of the coupling product and substrate scope of this reaction was carried out. Finally, the applicability of the CuSAC reaction for bioconjugation was demonstrated by an example of protein labeling
Meslamani, Jamel-Eddine. "Développement de nouvelles méthodes de criblage in silico en chémogénomique." Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAF009/document.
Chemoinformatics and bioinformatics methods are now necessary in every drug discovery program. Pharmaceutical industries dedicate more than 10% of their research and development investment in computer aided drug design (Kapetanovic 2008). The emergence of these tools can be explained by the increasing availability of high performance calculating machines and also by the low cost of in silico analysis compared to in vitro tests.Biological tests that were performed over last decades are now a valuable source of information and a lot of databases are trying to list them. This huge amount of information led to the birth of a new research field called “chemogenomics”. The latter is focusing on the identification of all possible associations between all possible molecules and all possible targets. Thus, using chemogenomics approaches, one can obtain a biological profile of a molecule and even anticipate possible side effects.This thesis was focused on the development of approaches that aim to predict the binding of molecules to targets. In our lab, we focus on profiling molecular databases in order to get their full biological profile. Thus, my main work was related to this context and I tried to develop predictive models to assess the binding of ligands to proteins, to validate some virtual screening methods for profiling purpose, and finally, I developed an automatic hybrid profiling workflow that selects the best fitted virtual screening approach to use according the ligand/target context
DULAC-BRACQ, EMMANUELLE. "Criblage par dosage immunochimique de souches recombinantes chez penicillium roquefortii." Clermont-Ferrand 2, 1997. http://www.theses.fr/1997CLF21886.
Hortholary, Cédric. "Criblage de structures chimiques : modèles de composants pour l'électronique moléculaire." Toulouse 3, 2003. http://www.theses.fr/2003TOU30227.
Molecular wires and switches are of crucial interest in the growing field of molecular electronics. Most of the syntheses of this type of molecules, presented in this work, are based on the properties of a cationic cyclometallated ruthenium complex, used as a builiding block. A familly of various length, unsaturated and redox active oligo(phenyl)ethynyl (OPE) has been obtained. We have studied the electrical behaviour of these molecules by electrochemical techniques. Experimentally the molecules probed are embedded in a self assembled monolayer, characterised by scanning tunnelling microscopy. By recording the heterogeneous rate constants of OPE, we have determined the distance dependence of the tunneling parameter
Marin, Annick. "Pervaporation microfluidique pour le criblage et mesures de concentration in situ." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2009. http://pastel.archives-ouvertes.fr/pastel-00555545.
Elkaïm, Judith. "Drug design in silico : criblage virtuel de protéines à visée thérapeutique." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14444/document.
The process of drug discovery is long and tedious. Besides, it is relatively inefficient in terms of hit rate. The identification of candidates through experimental testing is expensive and requires extensive data on the mechanisms of the target protein in order to develop efficient assays. Virtual screening can considerably accelerate the process by quickly evaluating large databases of compounds and determining the most likely to bind to a target. Some success stories have emerged in the field over the last few years.The objectives of this work were first, to compare common tools and strategies for structure-based virtual screening, and second, to apply those tools to actual target proteins implied notably in carcinogenesis.In order to evaluate the docking and scoring programs available, the protein kinase GSK3 and a test set of known ligands were used as a model to perform methodological studies. In particular the influence of the flexibility of the protein was explored via relaxed structures of the receptor or the insertion of torsions on the side chains of residues located in the binding site. Studies concerning the automatic generation of 3D structures for the ligands and the use of consensus scoring also provided insights on the usability of these tools while performing a virtual screening.Virtual screening of the human protein Pontin, an ATPase implied in tumor cell growth for which no inhibitors were known, allowed the prioritization of compounds from commercial databases. These compounds were tested in an enzymatic assay via a collaboration, and led to the identification of four molecules capable of inhibiting the ATPase activity of Pontin. Additional screens of in-house oriented databases also provided at least one innovative inhibitor for this protein. On the contrary, a study of the human PLA2-X, a phospholipase that requires a Ca2+ atom to bind to its active site in order to catalyze the hydrolysis of its substrate, revealed the limits of our docking tools that could not handle the metal ion and the need for new tools
Chtchigrovsky, Mélanie. "Préparation, criblage et utilisation de catalyseurs hétérogènes à base de polysaccharides." Paris 11, 2010. http://www.theses.fr/2010PA112144.
Environmental constraints push chemists to develop new systems for generating minimal waste. The development of well-defined heterogeneous catalysts can respond to these constraints in particular by the recovery and the recycling of catalyst. While many heterogeneous catalytic systems based on inorganic or organic materials are already reported in the literature, few works implement systems based on biological materials such as natural polymeric macrostructures. In this context, we have undertaken to develop heterogeneous catalysts based on polysaccharides as renewable materials, in the form of macroscopic porous beads. Different catalysts obtained were screened using fluorescent test. Firstly, the catalytic efficiency of a dozen heterogeneous catalysts based on chitosan as support for « copper-ligand » complexes has been studied through the 1,3-dipolar Huisgen’s cycloaddition. Secondly, the catalytic efficiency of around forty heterogeneous systems based on palladium nanoparticles supported on alginate have been studied through the Suzuki’s coupling reaction. Our results show that highly active heterogeneous systems can be obtained by combining the structural properties of polysaccharides and catalytic properties of transition metals or « metal-ligand » complexes
Lecat-Guillet, Nathalie. "Identification d’inhibiteurs du symporteur sodium-iode par criblage à haut débit." Paris 11, 2006. http://www.theses.fr/2006PA112345.
Gaignard, Clément. "Criblage, identification et caractérisations physico-chimiques d'exopolysaccharides de microalgues et Cyanobactéries." Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC067.
The main objective of this thesis was to improve knowledge on the capacity of microalgae and Cyanobacteria to produce Exopolysaccharides (EPS). Screening carried out on 166 strains from the Roscoff Culture Collection (RCC) made it possible to identify 45 new potentially EPS producers. Biochemical studies using High Performance Anion Exchange Chromatography with a Pulsed Amperometric Detector (HPAEC-PAD), and Gas Chromatography with Mass Spectrometry (GC/MS) confirmed the polysaccharide nature of 20 new identified polymers. During this work, cultures in 1,4 and 5 L Photobioreactors (PBR) were performed on few strains in order to characterize at best their EPS (biochemical compositions and physicochemical characteristics). This word led, in addition, to the identification of a heteroxylan from the microalga Glossomastix. Its EPS consists of a main chain of β-(1,3)- and β-(1,4)-d-Xylp substituted in O-2 and O-3 positions by various chains and/or terminal residues such as d-Xylp-(1→6)-d-Galp, d-Xylp-(1→4)-d-Galp, d-Xylp-(1→3)-d-Galp, Galp-(1⟶SF-Xylp-(1⟶Xylp-(1⟶Glcp-(1⟶. Finally statistical analyzes carried out on 81 monosaccharide compositions of microalgae EPS made it possible for the first time to establish a link between biochemical composition and phylogenetic membership of microalgae
Seveno, Martial. "Le rhamnogalacturonane II : Développement d’outils de criblage de mutants d’Arabidopsis thaliana." Rouen, 2006. http://www.theses.fr/2006ROUES048.
Rhamnogalacturonan II is a very complex mega-oligosaccharide which is present in plant primary cell walls, predominantly as a dimer that is cross-linked by a borate-diol ester. RG II dimerization is a fundamental process for plant growth. Furthermore, in spite of its complexity, the structure of this polymer is highly conserved in plants, which presume a strong implication of the RG II in important physiological functions. The RG II represents only 4% of the cell wall components. The study of insertion mutants of Arabidopsis thaliana affected in the biosynthesis of this polymer could allow answering the numerous questions about RG II. Amonf these “RG II” mutants, some present deficiencies for key enzymes of the Kdo biosynthesis pathway. Kdo is a specific monosaccharide present in RG II polysaccharide. RG II purification and structural analysis methodologies have been developed and validated prior to biochemical and molecular studies of “Kdo” mutants
Choucha-Snouber, Leïla. "Développement d'un bioréacteur microfluidique hépato-rénal pour le criblage des xénobiotiques." Compiègne, 2012. http://www.theses.fr/2012COMP2005.
The aim of my thesis was to develop a liver-Kidney microfluidic bioreactor to test the toxicity of xenobiootics on the kidney. For that MDCKcells (kidney dog cells) were selected as the model. The study of the mechanisms of cell adaptability to the microenvironment and continuous flow showed that the cells proliferatein 3-D and have an inflammatory statute. The transcriptome analysis has allowed us to identify genes of the specific kidney functions and the phase I and II of metabolism. These results are supported by a proteomic profile. Thus the microconfinment and the flow are involved in maintaining functions of the renal cells, and adaptive response to the inflammatory condition. By the same experimental approach we have identified the main signaling pathways modulated by ifosfamide, an anticancer nephrotoxic drug metabolized by the liver. Thereby, our results allowed using the MDCK cells within a compound co-culture model with the liver model predetermined by the team. The co-culture of the two cell types allowed us to detect the metabolism of ifosfamide by the HepaRG (live cells) and the toxic effect of its metabolites on MDCK cells. Analysis of culture medium compounds by chromatography mass spectrometry show that the effect observed is due to chloroacetaldehyde, the nephrotoxic metabolite. Works of this thesis confirms the usefulness of our device as a means to evaluate the toxicity and/or the effectiveness of a drug, discover new therapeutic targets and identifying new biomarkers
Marin, Moumen Annick. "Pervaporation microfluidique pour le criblage et mesures de concentration in situ." Paris 6, 2009. https://pastel.archives-ouvertes.fr/pastel-00555545.
Parez, Vincent. "Criblage phénotypique à l'aide d'intracorps dans un modèle de cancer colorectal." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20109/document.
Intracellular expression of antibodies (intrabodies) permitted the study and targeting of antigens in cellular compartments. However, the expression of functional intrabodies remains a difficult task due to their large size, structure, and the reducing intracellular environment. Our group has a strong expertise in the field of intracellular immunization and the identification of new therapeutic targets. For this purpose, we have developed an scFv library optimized for intracellular expression of scFv antibody fragments. Our previous works have shown the successful use of intrabodies for targeting specific domains or post-translational modifications in living cells. This is particularly important because it demonstrates one of the main advantages of intrabodies compared to the approaches using RNAi. This benefit was demonstrated by a phenotypic screen in a model of allergy. Applying this approach to the study of mast cell activation, we identified a new molecular player involved in the signaling pathway implemented. This work was protected by a European patent in 2013 and was recently published. As part of my thesis project, I designed a new synthetic library (HUSCIv) optimized for scFv stability, diversity and affinity. For this, a highly soluble and hyper-stable framework, scFv13R4 isolated in our group, was used as a scaffold for grafting different hypervariable loops, while respecting the diversity of CDRs observed in human natural antibodies. We used protein GFP as a reporter to study the folding and solubility of intrabodies. Our findings clearly demonstrated that most of the intrabodies from HUSCIv library are soluble in the cytoplasm of mammalian cells. My thesis project described here reports the use of HUSCIv in a phenotypic screen of colorectal cancer cells carrying a mutation in the K-RAS gene and resistant to the treatment with the chimeric antibody Cetuximab. The project seeks to select scFv fragments able to restore the sensitivity to Cetuximab, with the objective to identify the intracellular targets involved. For this functional screen, the HUSCIv library was expressed in HCT116 cells via a retroviral expression system. The selection process is based on the direct selection of cell proliferation using a fluorescent dye (CMRA). The cells whose proliferation is blocked are isolated and the evolution of scFv populations throughout the experiment are tracked via high-throughput sequencing. This sequencing requires a large number of scFvs to perform a statistical analysis. So far, we have achieved two rounds of selection. The cytotoxicity tests carried out on the selected populations showed a significant inhibition of proliferation (10%) in the presence of Cetuximab. These results indicate that the evolving phenotypes are tending towards a selection of scFv inhibitors and suggest that we need to perform at least one or more selective rounds before making conclusions. The approach introduced here is different from all existing studies in that it uses "naive" libraries not only to respond to the diversity of the proteome, but also to study secondary messengers and metabolism in cells. As such, and in comparison to other large-scale approaches, it is a simple way for the discovery of potential therapeutic molecules
Bret, Emmanuelle. "Les anticancéreux d'origine végétale : historique et tests de criblage in vitro." Bordeaux 2, 1995. http://www.theses.fr/1995BOR2P109.
Lombardi, Vincent. "Criblage et caractérisation d'adjuvents pour les vaccins sublinguaux contre les allergies." Paris 6, 2008. http://www.theses.fr/2008PA066332.
Al, Ibrahim Malak. "Anti-coronavirus potential of halophytes and invasive plants from Northern France : discovery of active terpenoids from Hippophae rhamnoides and Senecio inaequidens." Electronic Thesis or Diss., Université de Lille (2022-....), 2024. http://www.theses.fr/2024ULILS003.
Coronaviruses are responsible for mild to severe respiratory tract illnesses in humans. Despite significant advancements in understanding coronavirus pathology and clinical management, these viral diseases remain a public health concern due to recurrent outbreaks driven by the emergence of variants, unequal access to COVID-19 treatments, inadequate vaccination rates and untreated high-risk populations. Thus, it is imperative to proactively develop specific and affordable antiviral solutions to control and prevent future pandemics. Plants exposed to abiotic stress factors and new environments represent a vast source of bioactive compounds. In this project, we investigated the antiviral potential in vitro of different halophytes, less salt-tolerant plants and invasive plants collected in the North of France against different coronaviruses.In the first part of the project, a variety of strictly halophytes and relatively salt-tolerant plants growing on the coastline in northern France were screened for their in vitro antiviral activity against different coronaviruses. The most active plant species, Hippophae rhamnoides L. (Eleagnaceae), underwent bioguided fractionation to identify active natural products. Six compounds were isolated from the three most active fractions using preparative HPLC and were identified as cinnamoyl triterpenoids through HRMS and mono- and bi-dimensional NMR. Infection tests demonstrated a dose-dependent inhibition of these triterpenes against HCoV-229E and SARS-CoV-2, notably highlighting their activity against both viruses.In the second part of the project, the antiviral potential against coronaviruses of Senecio inaequidens (Asteraceae), an invasive plant species, was explored. Six compounds purified by CPC and preparative HPLC were identified as sesquiterpenoid derivatives. They displayed a dose-dependent inhibitory effect on HCoV-229E and four of them also exhibited inhibition against SARS-CoV-2.Our findings suggest that Hippophae rhamnoides and Senecio inaequidens could represent potential sources of antiviral agents against human coronaviruses
ledroit, Véronique. "Recherche de principes actifs antitumoraux extraits de spongiaires : sélection par criblage à haut débit." Toulouse 3, 2002. http://www.theses.fr/2002TOU30249.
Baudoin, R. "Développement et caractérisation d'une puce à cellules pour le criblage d'agents toxiques." Phd thesis, Université de Technologie de Compiègne, 2008. http://tel.archives-ouvertes.fr/tel-00342342.
Dans cette étude, nous avons testé trois débits (0, 10 et 25 µL/min) et trois ensemencements cellulaires. Enfin, nous avons soumis notre biopuce à trois chargements de chlorure d'ammonium (0, 5 et 10 mM) afin de démontrer le potentiel de ce modèle pour de futures applications liées à la toxicité. L'activité cellulaire en biopuce a été suivie par la prolifération des cellules, les consommations de glucose et de glutamine, les productions d'albumine et d'ammoniac et enfin, par l'activité enzymatique de détoxification des CYP 1A.
En condition dynamique, il a été observé une augmentation des consommations et des productions cellulaires au regard des conditions statiques. L'activité de détoxification des CYP 1A a été également accrue. En présence du chlorure d'ammonium les réponses cellulaires furent similaires en biopuce au regard des conditions de culture standard en Pétri. De plus, le chlorure d'ammonium a semblé induire l'activité des CYP 1A en biopuce.
Par cette étude, nous montrons la pertinence de notre biopuce pour des tests de toxicité in vitro en condition dynamique. Ce nouveau modèle de culture cellulaire in vitro pourra à terme être applicable aux études de criblages dans les industries chimiques, pharmaceutiques et cosmétiques.
Asses, Yasmine. "Conception par modélisation et criblage in silico d'inhibiteurs du récepteur c-Met." Phd thesis, Université Henri Poincaré - Nancy I, 2011. http://tel.archives-ouvertes.fr/tel-00653609.
Ceccaldi, Alexandre. "Conception d'un criblage d'inhibiteurs des méthyltransférases d'ADN : vers de nouveaux modulateurs épigénétiques." Paris 6, 2011. http://www.theses.fr/2011PA066250.
Sperandio, Olivier. "Applications et développements informatiques de protocoles de drug design et criblage virtuel." Paris 5, 2007. http://www.theses.fr/2007PA05P612.
This thesis in structural bioinformatics and chemoinformatics concentrates on the optimization of the therapeutics compounds identification process. It relies on the three main components of the chemical compounds virtual screening: preparation of a computational version of the chemical library to be screened; identification of novel active compounds using chemical similarity with respect to known active molecules (LBVS); and identification of novel active compounds using the 3D structure of the target binding site (SBVS). This work implied: to develop a computer program (MED-3DMC) that generates conformation ensembles of small molecules ; then to create a LBVS program (MED-SuMoLig) that can screen thousands of chemical compounds using their pharmaco-topological profile; and finally to use a hierarchical SBVS procedure to identify novel inhibitors for protein-membrane interaction using the coagulation factor Va as a proof of concept
Amine, Chloe. "Millifluidique à gouttes : un outil pour le criblage des interactions entre biopolymères." Thesis, Nantes, 2017. http://www.theses.fr/2017NANT4120.
Liquid-liquid phase separation of aqueous biopolymers mixtures has been shown to strongly depend on various physico-chemical parameters. One sub-type of liquidliquid phase separation is known as complex coacervation and is primarily driven by attractive electrostatic interactions among two oppositely charged biopolymers. Understanding and characterizing specific conditions and factors leading to phase separated systems is an essential preliminary step in the further development of high values products that take advantage of such phenomenon. However, these screening studies, usually performed in bulk, are highly time consuming and require large quantities of raw materials not always available and sometimes expensive. The aim of this work was to develop a low material consuming droplets-based millifluidic device for the rapid screening of biopolymers interactions. The efficiency of the millifluidic device was demonstrated using a well-known case study of complex coacervation made of a protein-polysaccharide mixture, the ßlactoglobulin/ Gum Arabic mixture. This millifluidic device was then integrated in a multi-technics approach to study a second protein-polysaccharide mixture made of Napin and Pectin. The proposed millifluidic device is easy to implement and is therefore accessible to many laboratories. lt provides a low material consuming approach for rapid screening of biopolymers interactions, which is a prerequisite in the study of phase separation mechanisms
LEGENDRE, FREDERIC. "Recherche de microorganismes producteurs d'herbicides : criblage, production, purification et identification des produits." Toulouse 3, 1989. http://www.theses.fr/1989TOU30144.
Vézina-Dawod, Simon. "Design, synthèse et criblage de chimiothèques peptidomimétiques pour la découverte d'agents antinéoplasiques." Doctoral thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/28267.
Targeting protein-protein interactions represents an innovative and under-exploited therapeutic approach by the pharmaceutical industry and biomedical research. Because of their physicochemical nature, protein-protein interactions represent a major challenge for conventional screening methods with small molecule libraries. Indeed, the chemical space covered by the molecular structures found in the available libraries is poorly adapted to the reality of protein-protein interactions. In order to develop privileged and better adapted structures, the medicinal chemist must understand the nature of these interactions and move away from the traditional dogma of the so-called drug-like molecules. Peptides are excellent candidates for studying these interactions, nevertheless their pharmacological properties are generally disappointing in vivo. Peptidomimetism is then a more than relevant concept to combine the selectivity and efficiency of interaction against proteins with the concepts of bioavailability and metabolic stability. Many peptidomimetic platforms are available or emerging, and several major challenges are on the horizon. Indeed, the incorporation of a large molecular diversity and the adaptation of these platforms with the high throughput biological screening methods are only a few examples of the challenges that chemists and biochemists will have to meet. This work deals with the development and exploitation of different peptidomimetic molecular diversities, either macrocyclic or heterocyclic, but which serve the same purpose: to exploit privileged structures to discover new modulators of protein-protein interactions or simply innovative bioactive agents with advantageous pharmacological properties.
Boussouar, Amina. "Effet de position télomérique et criblage moléculaire : vers de nouvelles cibles télomériques." Lyon, Ecole normale supérieure, 2010. http://www.theses.fr/2010ENSL0597.
Telomeres are protective structures present at the ends of linear chromosomes and consist of simple repeated DNA sequences and specialized proteins. They are essential for the stable maintenance of eukaryotic chromosomes and they can regulate the lifespan of cells. In addition to their essential functions, telomeres are, in diverse organisms, specialized sites with regard to gene expression. Indeed, the transcription of genes located next to telomeres is repressed: this phenomenon was termed telomere position effect (TPE). As observed in the yeast, S. Cerevisiae -where TPE is best characterized- TPE in human cells depends of both telomere length and architecture. The treatment of cells with Trichostatin A, an inhibitor of class I and II histone deacetylases antagonizes TPE while treating the cells with 5-aza-2’-deoxycytidin, a demethylating agent, has no apparent effect on telomeric repression. Overall, position effects at human chromosome ends are dependent on a specific higher-order organization of the telomeric chromatin. In order to identify new molecules able to modulate TPE in human cells, we carried out the screening of the «Prestwick Chemical Library », a bank of bioactive molecules, on the CMBA-CEA platform in Grenoble. A total of 15 molecules were identified as anti-TPE factors after primary and secondary screening based on the increase in fluorescence measurement. After testing all of these molecules in our laboratory, two polyphenols, Acacetin and Chrysin, were retained as potent inhibitors of TPE and further characterized as drugs targeting telomeres specifically. We then asked whether TPE reversal was dependent on telomere length. The incubation in the presence of Acacetin and Chrysin affects telomere length suggesting that increased expression of the subtelomeric reporters is associated with a shortening of telomeres. To check whether these molecules revert telomeric silencing, by affecting telomere integrity, we analyzed chromosome stability in cells treated with Acacetin or Chrysin. The two molecules exhibit a rapid increase in the frequency of telomere induced DNA damage foci, suggesting that these drugs trigger telomeric dysfunction. Drug treatment also significantly increases the frequency of telomeric abnormalities observed in metaphase with a significant increase of end-to-end fusions between sisters chromatid. The discovery of these new compounds targeting specifically chromosome ends opens new avenue for the targeted treatment of diseases linked to telomeric pathways such as cancer but also rare diseases such as Facio-Scapulo-Humeral dystrophy for which we investigated the molecular mechanisms
Rozié, Alexandrine. "Criblage de petites molécules d'intérêt thérapeutique et recherche de leur mécanisme d'action." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30246.
The identification of the mechanism of action of small bioactive molecules allows (i) to reveal unexpected pharmacological targets against which new therapeutic molecules that can be developed, (ii) to discover original modes of action that can inspire the development of new drugs, and (iii) to develop biomarkers of response to these treatments. The objective of my thesis was to apply several target identification approaches to small molecules, either new, from a phenotypic screen, or already known but the mechanism of action of which was not identified. In a first part of my work, a phenotypic screen was developed in order to identify in the " Chimiothèque Nationale Essentielle ", new sensitizers to the prototype of a family of DNA-damaging anti-cancer agents, camptothecin (CPT). CPT is a poison of topoisomerase I, inducing a particular type of double-strand DNA breaks (DSB) associated with replication forks. This screen led to the identification of a new sensitizer that we named Shuri1. We have established that Shuri1 induces DSB selectively in replicating cells. We demonstrated that Shuri1 behaves as an inhibitor of the CHK1 protein kinase involved in the signaling of DNA damage. Accordingly, some mutations conferring resistance to a specific CHK1 inhibitor also confer resistance to Shuri1. In a second part of my thesis, I studied the mechanism of action of Jaspine B, a natural molecule derived from marine sponges that exhibits strong cytotoxicity against different human solid tumor cell lines. Previously, several mechanisms have been proposed for Jaspine B, but none accounts for the cellular effects of this molecule. In collaboration with Yves Génisson's team at the SPCMIB in Toulouse, a clickable analogue of jaspine B was synthesized and was localized by cell microscopy as aggregates at the endoplasmic reticulum (ER). Using lipidomics, functional genomics and real-time imaging, we have established a model of the Jaspine B mechanism of action in cancer cells. My work supports that Jaspine B behaves as a prodrug that is bioactivated by one of the ceramide synthases, enzymes involved in ceramide biosynthesis. The N-Acylated Jaspine B thus produced at the ER accumulates as aggregates responsible for the permeabilization of the ER and of the cell leading to cell death. We further established that this mechanism also explains the cytotoxic effects of another lipid produced by marine sponges