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International audience; It is critical that novel classes of antituberculosis drugs are developed to combat the increasing burden of infections by multidrug-resistant strains. To identify such a novel class of antibiotics, a chemical library of unique 3-D bioinspired molecules was explored revealing a promising, mycobacterium specific Tricyclic SpiroLactam (TriSLa) hit. Chemical optimization of the TriSLa scaffold delivered potent analogues with nanomolar activity against replicating and nonreplicating Mycobacterium tuberculosis. Characterization of isolated TriSLa-resistant mutants, and biochemical studies, found TriSLas to act as allosteric inhibitors of type II NADH dehydrogenases (Ndh-2 of the electron transport chain), resulting in an increase in bacterial NADH/NAD+ ratios and decreased ATP levels. TriSLas are chemically distinct from other inhibitors of Ndh-2 but share a dependence for fatty acids for activity. Finally, in vivo proof-of-concept studies showed TriSLas to protect zebrafish larvae from Mycobacterium marinum infection, suggesting a vulnerability of Ndh-2 inhibition in mycobacterial infections.

International audience; Decoy technology is a versatile and specific DNA oligonucleotide-based targeting strategy of pathogenic transcription factors (TFs). Chemical modifications of linear decoy oligonucleotides have been made to decrease nuclease sensitivity because of the presence of free ends but at the cost of new limitations that affect their use as therapeutic drugs. Although a short DNA minicircle is a phosphodiester nucleic acid without free ends, its potential therapeutic activity as a TF decoy oligonucleotide has not yet been investigated. Here we describe the in vitro and in vivo activity of formulated 95-bp minicircles bearing one or several STAT3 binding sequences in triple-negative breast cancer (TNBC). Minicircles bearing one STAT3 binding site interacted specifically with the active form of STAT3 and inhibited proliferation, induced apoptosis, slowed down cell cycle progression, and decreased STAT3 target gene expression in human and murine TNBC cells. Intratumoral injection of STAT3 minicircles inhibited tumor growth and metastasis in a murine model of TNBC. Increasing the number of STAT3 binding sites resulted in improved anticancer activity, opening the way for a TF multitargeting strategy. Our data provide the first demonstration of minicircles acting as STAT3 decoys and show that they could be an effective therapeutic drug for TNBC treatment.

International audience; In our ongoing search for bioactive compounds, a class of novel spiro-β-lactam isatin hybrids has been synthesized through a [2 + 2] cycloaddition reaction from 1-allyl-3-(arylimino)indolin-2-one, ketenes and various aryloxy acetic acids. The formation of all cycloadducts was confirmed by FTIR, 1H NMR, 13C NMR, and mass spectroscopy as well as elemental analyses. The new β-lactams were subsequently evaluated for their biological activities demonstrating moderate to good activities against P. falciparum K1 strain. Among them, 4b and 4e lead to the best results with IC50 of 5.04 and 7.18 µM, respectively. The molecular docking simulation of 4b with P. falciparum dihydrofolate reductase enzyme (PfDHFR) binding site presented several important intermolecular interactions. All the synthesized β-lactams were also evaluated for their antimicrobial activities against both Gram-positive (S. aureus ATCC 25923) and Gram-negative bacteria (E. coli ATCC 28922, P. aeruginosa ATCC 27853) but unfortunately MICs up to 200 µg/mL were encountered in all cases.

International audience; nhibiting receptor tyrosine kinases is commonly achieved by two main strategies targeting either the intracellular kinase domain by low molecular weight compounds or the extracellular ligand-binding domain by monoclonal antibodies. Identifying small molecules able to inhibit RTKs at the extracellular level would be highly desirable to gain exquisite selectivity but is believed to be challenging owing to the size of RTK endogenous ligands (cytokines, growth factors) and the topology of RTK extracellular domains. We here report the high-throughput screening of the French Chemical Library (48K compounds) for extracellular inhibitors of the Fms-like tyrosine kinase 3 (FLT3) receptor tyrosine kinase, by a homogeneous time-resolved fluorescence competition assay. A total of 679 small molecular weight ligands (1.4%) were confirmed to strongly inhibit (>75%) the binding of the fluorescent labeled FLT3 ligand (FL cytokine) to FLT3 overexpressed in HEK-293 cells, at two different concentrations (5 and 20 μM). Concentration-response curves, obtained for 111 lead-like molecules, confirmed the unexpected tolerance of the FLT3 extracellular domain for low molecular weight druggable inhibitors exhibiting submicromolar potencies, chemical diversity, and promising pharmacokinetic properties. Further investigation of one hit confirmed inhibitory properties in dorsal root ganglia neurons and in a mouse model of neuropathic pain.

International audience; The development of nanocomposite supramolecular hydrogels, which can be activated by local or external stimuli (pH, redox, enzyme, heat), is highly promising for various applications including implantable materials for antitumor or tissue engineering applications. Here, we show that large pore stellate mesoporous silica modified with isobutyramide grafts allow >100% wt. loading of enzymes, which ensures through the enzyme-assisted self-assembly an easy, rapid, and efficient way to design smart thermoresponsive nanocomposite supramolecular hydrogels. The typical temperature increase (42 °C), which may be induced by hyperthermia anticancer treatments, leads to the controlled-release of doxorubicin encapsulated in the resulting peptide self-assembled material.

International audience; The development of inhibitors of anti-apoptotic proteins, such as Mcl-1, is currently a very active area in the field of cancer research. One of the very first reported inhibitor of Mcl-1 was the molecule MIM1, but we have demonstrated recently that the structure of this compound had to be revised from 2 to the derivative 1 (FJ-809). In this paper we first develop a strategy to prepare unambiguously molecules such as 1 with a thiazol-3(2H)-yl)imino core, instead of the [2(3H)thiazolylidene]hydrazine previously found in MIM1 (2). Next a series of biological studies have been performed on 1, using IGROV1-R10 ovarian cancer cells as models, and they have been complemented by Fluorescence Polarisation Assays. These studies demonstrated that the new compound FJ-809 (1) was devoid of any significant activity on Mcl-1, contrary to 2. Then molecular modelling and molecular dynamic studies have been performed in order to elucidate the differences between FJ-809 and MIM1 in their interaction with the Mcl-1 protein.

Highly pleiotropic and constitutively active protein kinase CK2 is a key target in cancer therapy, but only one small-molecule inhibitor has reached clinical trials—CX-4945. In this study, we present the indeno[1,2-b]indole derivative 5-isopropyl-4-methoxy-7-methyl-5,6,7,8-tetrahydroindeno[1,2-b]indole-9,10-dione (5a-2) that decreased the intracellular CK2 activity in A431, A549, and LNCaP tumor cell lines analogous to CX-4945 (> 75% inhibition at 20 µm) and similarly blocked CK2-specific Akt phosphorylation in LNCaP cells. Cellular uptake analysis demonstrated higher intracellular concentrations of 5a-2 (408.3 nm) compared with CX-4945 (119.3 nm). This finding clarifies the comparable effects of both compounds on the intracellular CK2 activity despite their different inhibitory potency in vitro [IC50 = 25 nm (5a-2) and 3.7 nm (CX-4945)]. Examination of the effects of both CK2 inhibitors on cancer cells using live-cell imaging revealed notable differences. Whereas CX-4945 showed a stronger pro-apoptotic effect on tumor cells, 5a-2 was more effective in inhibiting tumor cell migration. Our results showed that 49% of intracellular CX-4945 was localized in the nuclear fraction, whereas 71% of 5a-2 was detectable in the cytoplasm. The different subcellular distribution, and thus the site of CK2 inhibition, provides a possible explanation for the different cellular effects. Our study indicates that investigating CK2 inhibition-mediated cellular effects in relation to the subcellular sites of CK2 inhibition may help to improve our understanding of the preferential roles of CK2 within different cancer cell compartments., Finanziert über die DEAL-Vereinbarung mit Wiley 2019-2022.

Invasive fungal infections caused by Candida species remain a significant public health problem worldwide. The increasing prevalence of drug-resistant infections and a limited arsenal of antifungal drugs underscore the need for novel interventions. Here, we screened several classes of pharmacologically active compounds against mammalian diseases for antifungal activity. We found that the synthetic triazine-based compound melanogenin (Mel) 56 is fungicidal in Candida albicans laboratory and clinical strains with minimal inhibitory concentrations of 8–16 µg/mL. Furthermore, Mel56 has general antifungal activity in several non-albicans Candida species and the non-pathogenic yeast Saccharomyces cerevisiae. Surprisingly, Mel56 inhibited the yeast-to-hyphae transition at sublethal concentrations, revealing a new role for triazine-based compounds in fungi. In human cancer cell lines, Mel56 targets the inner mitochondrial integral membrane prohibitin proteins, PHB1 and PHB2. However, Mel56 treatment did not impact C. albicans mitochondrial activity, and antifungal activity was similar in prohibitin single, double, and triple homozygous mutant strains compared to the wild-type parental strain. These results suggests that Mel56 has a novel mechanism-of-action in C. albicans. Therefore, Mel56 is a promising antifungal candidate warranting further analyses.

International audience; Microalgae are photosynthetic microscopic organisms that serve as the primary food source in aquatic environments. Microalgae can synthesize a wide variety of molecules, such as polyunsaturated fatty acids (PUFAs) of the omega-3 and omega-6 series. Oxidative degradation of PUFA due to radical and/or enzymatic conversion leads to the formation of oxylipins, which are compounds known for their bioactive properties. In the present study, we aim to profile oxylipins from five microalgae species grown in 10-L photo-bioreactors under optimal conditions. During their exponential phase, microalgae were harvested, extracted and analyzed by LC-MS/MS to determine the qualitative and quantitative profile of oxylipins for each species. The five different selected microalgae revealed a high diversity of metabolites, up to 33 non-enzymatic and 24 enzymatic oxylipins present in different concentrations. Taken together, these findings highlight an interesting role of marine microalgae as a source of bioactive lipids mediators, which we hypothesize have an important function in preventive health measures such as amelioration of inflammation. The rich mixture of oxylipins may display advantages to biological organisms, especially by providing for human health benefits including antioxidant, anti-inflammatory, neuroprotective or immunomodulator activities. Some oxylipins are also well known for their cardiovascular properties.

International audience; Gold-(I) catalysis was used for the intramolecular cyclization of tertiary alcohols with terminal alkynes to form diverse aza-spirocycles. The reaction was carried out with low catalyst loading under microwave irradiation to give both sulfonylated and acylated spirocyclic nitrogen derivatives. Gram scale spirocyclization was carried out and demonstrates the robustness of the reaction. An intramolecular Mizoroki-Heck reaction was performed to give several tetracyclic spirocycles. Double bond reduction and selective protecting group manipulation gave spiropiperazine and spiromorpholine derivatives. These compounds were incorporated into biologically relevant scaffolds to give the first selective spirocyclic inhibitors of LIMK.

International audience; Limiting the serum protein fouling is a major challenge in the design of nanoparticles (NPs) for nanomedicine applications. Suitable chemical surface modification strategies allow to limit the interactions with adsorbing proteins. In this communication, we address the potential of isobutyramide (IBAM) groups grafted on stellate silica nanoparticles (STMS) for the immobilization of two biocompatible polymers renown for biomedical and low fouling applications: Hydroxypropylcellulose (HPC) and Pluronic F127 (PF127). We report that both polymers can be loaded on STMS@IBAM NPs surface with a maximum loading content close to 10 wt %. Regarding their antifouling properties, we report that the coatings of such HPC or PF127 polymers allow to reduce significantly the human serum albumin (HSA) adsorption in average by 70 % as compared to the surface of the free polymer STMS@IBAM. These results highlight the antifouling potential of these polymer pretreatments on IBAM-modified STMS NPs surface.

International audience; (1) Background: TDMQ20 is a specific regulator of copper homeostasis in the brain, able to inhibit cognitive impairment in the early stages of Alzheimer’s disease (AD) in mouse models of AD. To promote the further development of this drug-candidate, preliminary data on the pharmacokinetics of TDMQ20 in a mammal model have been collected. Since TDMQ20 should be administered orally, its absorption by the gastrointestinal tract was evaluated by comparison of blood concentrations after administration by oral and IV routes, and its ability to reach its target (the brain) was confirmed by comparison between blood and brain concentrations after oral administration. (2) Methods: plasmatic and brain concentrations of the drug after oral or intravenous treatment of rats at pharmacologically relevant doses were determined as a function of time. (3) Results: oral absorption of TDMQ20 was rapid and bioavailability was high (66% and 86% for males and females, respectively). The drug accumulated in the brain for several hours (brain–plasma ratio 3 h after oral administration = 2.6), and was then efficiently cleared. (4) Conclusions: these data confirm that TDMQ20 efficiently crosses the brain–blood barrier and is a relevant drug-candidate to treat AD.

International audience; G-quadruplexes (G4s), secondary structures adopted by guanine-rich DNA and RNA sequences, are implicated in numerous biological processes and have been suggested as potential drug targets. Accordingly, there is an increasing interest in developing high-throughput methods allowing the generation of congeneric series of G4-targeting molecules (“ligands”) and investigation of their interaction with the targets. Here, we developed an operationally simple method of parallel synthesis to generate “ready-to-screen” libraries of cationic acylhydrazones, a motif that we have previously identified as a promising scaffold for potent, biologically active G4 ligands. Combined with well-established screening techniques, such as fluorescence melting, this method enables rapid synthesis and screening of combinatorial libraries of potential G4 ligands. Following this protocol, we synthesized a combinatorial library of 90 bis(acylhydrazones) and screened it against five different nucleic acid structures. This way, we were able to analyze the structure-activity relationships within this series of G4 ligands, and identified three novel promising ligands whose interaction with G4-DNA of different topologies was carefully studied by a combination of several biophysical techniques, including native mass spectrometry, and molecular modeling.

International audience; Patients with cystic fibrosis (CF) have a significantly higher risk of acquiring nontuberculous mycobacteria infections, predominantly due to M. abscessus, than the healthy population. Because M. abscessus infections are a major cause of clinical decline and morbidity in CF patients, improving treatment and the detection of this mycobacterium in the context of a polymicrobial culture represents a critical component to better manage patient care. We report here the synthesis of fluorescent Dansyl derivatives of four active Cyclipostins and Cyclophostin analogs (CyC) and provide new insights regarding the CyC lack of activity against Gram-negative and Gram-positive bacteria, and above all into their mode of action against intramacrophagic M. abscessus cells. Our results pointed out that the intracellularly active CyC accumulate in acidic compartments within macrophage cells; that this accumulation appears to be essential for their delivery to mycobacteria-containing phagosomes, and consequently, for their antimicrobial effect against intracellular replicating M. abscessus; and that modification of such intracellular localization via disruption of endolysosomal pH strongly affect the CyC accumulation and efficacy. Moreover, we discovered that these fluorescent compounds could became efficient probes to specifically label mycobacterial species with high sensitivity, including M. abscessus in presence several other pathogens like P. aeruginosa and S. aureus. Collectively, all present and previous data emphasized the therapeutic potential of unlabeled CyC, and the attractiveness of the fluorescent CyC as potential new efficient diagnostic tool to be exploited in future diagnostic developments against mycobacterial-related infections, especially against M. abscessus.

International audience; A hallmark of Mycobacterium tuberculosis (M. tb), the etiologic agent of tuberculosis, is its ability to metabolize host-derived lipids. However, the enzymes and mechanisms underlying such metabolism are still largely unknown. We previously reported that the Cyclophostin & Cyclipostins (CyC) analogs, a new family of potent antimycobacterial molecules, react specifically and covalently with (Ser/Cys)-based enzymes mostly involved in bacterial lipid metabolism. Here, we report the synthesis of new CyC alkyne-containing inhibitors (CyCyne) and their use for the direct fishing of target proteins in M. tb culture via bio-orthogonal click-chemistry activity-based protein profiling (CC-ABPP). This approach led to the capture and identification of a variety of enzymes, many of them involved in lipid or steroid metabolisms. One of the captured enzymes, HsaD (Rv3569c), is required for the survival of M. tb within macrophages and is thus a potential therapeutic target. This prompted us to further explore and validate, through a combination of biochemical and structural approaches, the specificity of HsaD inhibition by the CyC analogs. We confirmed that the CyC bind covalently to the catalytic Ser114 residue, leading to a total loss of enzyme activity. These data were supported by the X-ray structures of four HsaD-CyC complexes, obtained at resolutions between 1.6-2.6 Å. The identification of mycobacterial enzymes directly captured by the CyCyne probes through CC-ABPP paves the way to better understand and potentially target key players at crucial stages of the bacilli life-cycle.

International audience; Hydrolysis of β-lactam drugs, a major class of antibiotics, by serine or metallo-β-lactamases (SBL or MBL) is one of the main mechanisms for antibiotic resistance. New Delhi Metallo-β-lactamase-1 (NDM-1), an acquired metallo-carbapenemase first reported in 2009, is currently considered one of the most clinically relevant targets for the development of β-lactam-β-lactamase inhibitor combinations active on NDM-producing clinical isolates. Identification of scaffolds that could be further rationally pharmacomodulated to design new and efficient NDM-1 inhibitors is thus urgently needed. Fragment-based drug discovery (FBDD) has become of great interest for the development of new drugs for the past few years and combination of several FBDD strategies, such as virtual and NMR screening, can reduce the drawbacks of each of them independently. Our methodology starting from a high throughput virtual screening on NDM-1 of a large library (more than 700,000 compounds) allowed, after slicing the hit molecules into fragments, to build a targeted library. These hit fragments were included in an in-house untargeted library fragments that was screened by Saturation Transfer Difference (STD) Nuclear Magnetic Resonance (NMR). 37 fragments were finally identified and used to establish a pharmacophore. 10 molecules based on these hit fragments were synthesized to validate our strategy. Indenone 89 that combined two identified fragments shows an inhibitory activity on NDM-1 with a K i value of 4 µM.

International audience; Vectorized small interfering RNAs (siRNAs) are widely used to induce gene silencing. Among the delivery systems used, lipid-based particles are the most effective. Our objective was the development of novel lipid-polymer hybrid nanoparticles, from lipoplexes (complexes of cationic lipid and siRNAs), and poly (lactic-co-glycolic acid) (PLGA), using a simple modified nanoprecipitation method. Due to their morphology, we called these hybrid nanoparticles Spheroplexes. We elucidated their structure using several physico-chemical techniques and showed that they are composed of a hydrophobic PLGA matrix, surrounded by a lipid envelope adopting a lamellar structure, in which the siRNA is complexed, and they retain surface characteristics identical to the starting nanoparticles, i.e. lipoplexes siRNA. We analyzed the composition of the particle population and determined the final percentage of spheroplexes within this population, 80 to 85% depending on the preparation conditions, using fluorescent markers and the ability of flow cytometry to detect nanometric particles (approximately 200 nm). Finally, we showed that spheroplexes are very stable particles and more efficient than siRNA lipoplexes for the delivery of siRNA to cultured cells. We administered spheroplexes contain siRNAs targeting TNF-α to mice with ulcerative colitis induced by dextran sulfate and our results indicate a disease regression effect with a response probably mediated by their uptake by macrophages / monocytes at the level of lamina propria of the colon. The efficacy of decreased level of TNF-α in vivo seemed to be an association of spheroplexes polymer-lipid composition and the specific siRNA. These results demonstrate that spheroplexes are a promising hybrid nanoparticle for the oral delivery of siRNA to the colon.

International audience; In line with recent clinical trials demonstrating that ondansetron, a 5-HT3 receptor (5-HT3R) antagonist, ameliorates cognitive deficits of schizophrenia and the known procognitive effects of 5-HT6 receptor (5-HT6R) antagonists, we applied the hybridization strategy to design dual-acting 5-HT3/5-HT6R antagonists. We identified the first-in-class compound FPPQ, which behaves as a 5-HT3R antagonist and a neutral antagonist 5-HT6R of the Gs pathway. FPPQ shows selectivity over 87 targets and decent brain penetration. Likewise, FPPQ inhibits phencyclidine (PCP)-induced hyperactivity and displays procognitive properties in the novel object recognition task. In contrast to FPPQ, neither 5-HT6R inverse agonist SB399885 nor neutral 5-HT6R antagonist CPPQ reversed (PCP)-induced hyperactivity. Thus, combination of 5-HT3R antagonism and 5-HT6R antagonism, exemplified by FPPQ, contributes to alleviating the positive-like symptoms. Present findings reveal critical structural features useful in a rational polypharmacological approach to target 5-HT3/5-HT6 receptors and encourage further studies on dual-acting 5-HT3/5-HT6R antagonists for the treatment of psychiatric disorders.

International audience; The synthesis of (1R)-2-amino-2-deoxy-β-L-gulopyranosyl benzene, and the α and β form of 2-amino-2-deoxy-Lidopyranosyl benzene derivatives was accomplished through stereospecific addition of tributylstannyllithium to readily available (SR)-or (SS)-N-tert-butanesulfinyl-arabinofuranosylamine building blocks, followed by stereoretentive Pd-catalyzed Migita-Kosugi-Stille cross-coupling, stereoselective reduction and an activation-cyclization strategy. Application of this methodology paves the way to new three-dimensional chemical space and preparation of unknown (non-natural) and complex 2-amino-2-deoxy sugars of biological interest.

International audience; In the present study, new 2-phenyl-5,6,7,8-tetrahydroimidazo [1,2-b]pyridazines bearing sulfonamides were synthesized, characterized and evaluated for their anticancer activities. The structures of these derivatives were elucidated by 1H NMR, 13C NMR, infrared and high-resolution mass spectrometry for further validation of the target compound structures. The anticancer activities of the new molecules were evaluated against five human cancer cell lines, including A-549, Hs-683, MCF-7, SK-MEL-28 and B16-F10 cell lines using 5-fluorouracil and etoposide as the reference drugs. Among the tested compounds, 4e and 4f exhibited excellent activities in the same range of the positive controls, 5-fluorouracil and etoposide, against MCF-7 and SK-MEL-28 cancer cell lines, with IC50 values ranging from 1 to 10 μM. The molecular docking studies of 4e and 4f showed a strong binding with some kinases, which are linked to MCF-7 and SK-MEL-28 cancer cell lines.

Fluorizoline is a cytotoxic trifluorothiazoline that targets the scaffold proteins prohibitins-1 and -2 (PHB1/2) to inhibit the kinase C-RAF and promote the expression of the cyclin-dependent kinase inhibitor p21 to induce cancer cell death. In melanocytes, fluorizoline also induces the synthesis of melanin. Herein we report the first structural requirement of fluorizoline analogues for these activities. We identified in particular some compounds that display enhanced anti-C-RAF and anti-MEK activities, and a higher cytotoxicity in HeLa cells compared to fluorizoline. These results provide a foundation for further optimization of PHB ligands for the treatment of cancers. We also discovered an analogue of fluorizoline that displays pharmacological effects opposed to those of fluorizoline and that can be used as a chemical tool to explore PHB signaling in cancers and other diseases.

The antibiotic tetracycline demeclocycline (DMC) was recently reported to rescue α-synuclein (α-Syn) fibril-induced pathology. However, the antimicrobial activity of DMC precludes its po-tential use in long-term neuroprotective treatments. Here, we synthesized a DMC derivative with residual antibiotic activity and improved neuroprotective effects. The molecule, called de-rivative demeclocycline (DDMC), was obtained by the removal of both dimethylamino substitu-ents at position 4 and the reduction of the hydroxyl group at position 12a on ring A of DMC. The modifications strongly diminished its antibiotic activity against Gram-positive and Gram-negative bacteria. Moreover, this compound preserved the low toxicity of DMC in dopaminergic cell lines while improving its ability to interfere with α-Syn amyloid-like aggregation, showing the highest effectiveness of all tetracyclines tested. Likewise, DDMC demonstrated the ability to reduce seeding induced by the exogenous addition of α-Syn preformed fibrils (α-SynPFF ) in ex vitro models and in SH-SY5Y-α-Syn-tRFP cells. In addition, in the presence of DDMC, α-SynPFF were less inflammogenic, as they dampened the release of tumor necrosis factor α (TNF-α) and glutamate by microglial cells compared to control fibrils. Our results suggest that DDMC may be a promising drug candidate for hit-to-lead development and preclinical studies in PD and other synucleinopathies.

Biosurfactant-aided liquid-phase exfoliation (LPE) is emerging as a biocompatible, green, economical, safe, and efficient approach to prepare two-dimensional (2D) materials for biomedical applications. However, relatively little is known about the molecular mechanisms of this process. Herein, we present the first study of how flavin mononucleotide (FMN) interacts with hexagonal boron nitride (hBN) nanosheets in the context of LPE. We demonstrate that FMN molecules can self-assemble on hBN via π-π interactions, as well as intermolecular hydrogen bonds (H-bonds) between the isoalloxazine moieties. Binding free energy analysis has shown FMN to be an efficient surfactant for LPE of hBN in water. According to the theoretical simulations, stable water suspension of hBN were experimentally obtained by LPE using FMN. With this work, we aim to exemplify how molecular dynamics (MD) simulation can predict and guide empirical LPE experiments, direct the surfactant screening and improve scalable production of 2D materials for biomedical applications. Ministry of Education (MOE) Nanyang Technological University Published version The authors gratefully acknowledge the financial support from the Singapore Ministry of Education (MOE) under T1 Award #020565-00001, a start-up grant from the Nanyang Technological University, and the Agence Nationale de la Recherche (ANR) (ANR-15-GRFL-0001-05, G-Immunomics). X.Q. acknowledges support from the Presidential Fellowship from Brown University. Molecular dynamics simulations reported were performed on resources provided by the Center for Computation and Visualization at Brown University, the High Performance Computing Centre at Nanyang Technological University, Singapore, and the National Supercomputing Centre, Singapore (http://www.nscc.sg). This work was partly supported by ANR through the LabEx project Chemistry of Complex Systems (ANR-10-LABX-0026_CSC). We wish to acknowledge the Centre National de la Recherche Scientifique (CNRS) and the International Center for Frontier Research in Chemistry (icFRC). The authors are indebted to Shi Guo and Lucas Jacquemin for their help on the exfoliation and characterization.

International audience; Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the infectious agent that has caused the current coronavirus disease (COVID) pandemic. Viral infection relies on the viral S (spike) protein/cellular receptor ACE2 interaction. Disrupting this interaction would lead to early blockage of viral replication. To identify chemical tools to further study these functional interfaces, 139,146 compounds from different chemical libraries were screened through an S/ACE2 in silico virtual molecular model. The best compounds were selected for further characterization using both cellular and biochemical approaches, reiterating SARS-CoV-2 entry and the S/ACE2 interaction. We report here two selected hits, bis-indolyl pyridine AB-00011778 and triphenylamine AB-00047476. Both of these compounds can block the infectivity of lentiviral vectors pseudotyped with the SARS-CoV-2 S protein as well as wild-type and circulating variant SARS-CoV-2 strains in various human cell lines, including pulmonary cells naturally susceptible to infection. AlphaLISA and biolayer interferometry confirmed a direct inhibitory effect of these drugs on the S/ACE2 association. A specific study of the AB-00011778 inhibitory properties showed that this drug inhibits viral replication with a 50% effective concentration (EC 50) between 0.1 and 0.5 mM depending on the cell lines. Molecular docking calculations of the interaction parameters of the molecules within the S/ACE2 complex from both wild-type and circulating variants of the virus showed that the molecules may target multiple sites within the S/ACE2 interface. Our work indicates that AB-00011778 constitutes a good tool for modulating this interface and a strong lead compound for further therapeutic purposes.

International audience; The aim of this study was to prepare and characterise inclusion complexes of a low water-soluble drug, mefenamic acid (MA), with b-cyclodextrin (b-CD). First, the phase solubility diagram of MA in b-CD was drawn from 0 to 21 Â 10 À3 M of b-CD concentration. A job's plot experiment was used to determine the stoichiometry of the MA:b-CD complex (2:1). The stability of this complex was confirmed by molecular modelling simulation. Three methods, namely solvent co-evaporation (CE), kneading (KN), and physical mixture (PM), were used to prepare the (2:1) MA:b-CD complexes. All complexes were fully characterised. The drug dissolution tests were established in simulated liquid gastric and the MA water solubility at pH 1.2 from complexes was significantly improved. The mechanism of MA released from the b-CD complexes was illustrated through a mathematical treatment. Finally, two in vitro experiments confirmed the interest to use a (2:1) MA:b-CD complex.

International audience; In the area of cancer research, the development of new and potent inhibitors of anti-apoptotic proteins is a very active and promising topic. The small molecule MIM1 has been reported earlier as one of the first selective inhibitors of the anti-apoptotic protein Mcl-1. In the present paper, we first revised the structure of this molecule based on extensive physicochemical analyses. Then we designed and synthesized a focused library of analogues for the corrected structure of MIM1. Next, these molecules were subjected to a panel of in cellulo biological studies, allowing the identification of dual Bcl-x(L)/Mcl-1 inhibitors, as well as selective Mcl-1 inhibitors. These results have been complemented by fluorescence polarization assays with the Mcl-1 protein. Preliminary structure-activity relationships were discussed and extensive molecular modelling studies allowed us to propose a rationale for the biological activity of this series of new inhibitors, in particular for the selectivity of inhibition of Mcl-1 versus Bcl-x(L).

International audience; Antibody–drug conjugates (ADCs) derived from a full immunoglobulin-G (IgG) are associated with suboptimal solid-tumor penetration and Fc-mediated toxicities. Antibody fragment–drug conjugates (FDCs) could be an alternative. Nevertheless, innovative solutions are needed to implant cysteines as conjugation sites in the single-chain fragment variable (scFv) format, which is the backbone from which many other antibody formats are built. In addition, the bioconjugation site has the utmost importance to optimize the safety and efficacy of bioconjugates. Our previous intra-tag cysteine (ITC) strategy consisted of introducing a bioconjugation motif at the C-terminal position of the 4D5.2 scFv, but this motif was subjected to proteolysis when the scFv was produced in CHO cells. Considering these data, using three intra-domain cysteine (IDC) strategies, several parameters were studied to assess the impact of different locations of a site-specific bioconjugation motif in the variable domains of an anti-HER2 scFv. In comparison to the ITC strategy, our new IDC strategy allowed us to identify new fragment–drug conjugates (FDCs) devoid of proteolysis and exhibiting enhanced stability profiles, better affinity, and better ability to kill selectively HER2-positive SK-BR-3 cells in vitro at picomolar concentrations. Thus, this work represents an important optimization step in the design of more complex and effective conjugates.

International audience; The aza‐Piancatelli cyclization provides an expedient synthesis of 4‐aminocyclopentenone building blocks that may be converted into aminocyclopentitols, which are heavily represented motifs among natural products. However, its use as a key step in total synthesis was still unprecedented. Here, we disclose our in‐depth investigations regarding this reaction in order to access highly complex structures representing the core of some natural molecules. The applicability of the cyclization was highlighted by the 3‐step total synthesis of bruceolline D. Thus, we anticipate that this work will lay the ground for further applications in total synthesis

International audience; The protein-protein interactions (PPIs) of 14-3-3 proteins are a model system for studying PPI stabilization. The complex natural product Fusicoccin A stabilizes many 14-3-3 PPIs but is not amenable for use in SAR studies, motivating the search for more drug-like chemical matter. However, drug-like 14-3-3 PPI stabilizers enabling such study have remained elusive. An X-ray crystal structure of a PPI in complex with an extremely low potency stabilizer uncovered an unexpected non-protein interacting, ligand-chelated Mg 2+ leading to the discovery of metal ion-dependent 14-3-3 PPI stabilization potency. This originates from a novel chelation-controlled bioactive conformation stabilization effect. Metal chelation has been associated with pan-assay interference compounds (PAINS) and frequent hitter behavior, but chelation can evidently also lead to true potency gains and find use as a medicinal chemistry strategy to guide compound optimization. To demonstrate this, we exploited the effect to design the first potent, selective and drug-like 14-3-3 PPI stabilizers.

International audience; Two series of piperazinyl-pyrrolo[1,2-a]quinoxaline derivatives were prepared via a Buchwald–Hartwig cross-coupling reaction and then evaluated for their ability to inhibit the drug efflux activity of CaCdr1p and CaMdr1p transporters of Candida albicans overexpressed in a Saccharomyces cerevisiae strain. In the initial screening of twenty-nine piperazinyl-pyrrolo[1,2-a]quinoxaline derivatives, twenty-three compounds behaved as dual inhibitors of CaCdr1p and CaMdr1p. Only four compounds showed exclusive inhibition of CaCdr1p or CaMdr1p. Further biological investigations were developed and for example, their antifungal potential was evaluated by measuring the growth of control yeast cells (AD1-8u−) and efflux pump-overexpressing cells (AD-CDR1 and AD-MDR1) after exposition to variable concentrations of the tested compounds. The MIC80 values of nineteen compounds ranging from 100 to 901 μM for AD-CDR1 demonstrated that relative resistance index (RI) values were between 8 and 274. In comparison, only seven compounds had RI values superior to 4 in cells overexpressing Mdr1p. These results indicated substrate behavior for nineteen compounds for CaCdr1p and seven compounds for CaMdr1p, as these compounds were transported via MDR transporter overexpressing cells and not by the AD1-8u− cells. Finally, in a combination assay with fluconazole, two compounds (1d and 1f) have shown a synergistic effect (fractional inhibitory concentration index (FICI) values ≤ 0.5) at micromolar concentrations in the AD-MDR1 yeast strain overexpressing CaMdr1p-protein, indicating an excellent potency toward chemosensitization.

International audience; Novel nucleoside derivatives were developed using the strategy of “terminal N,N-dimethylation” to impart tertiary amines to a 1,2,4-triazole nucleoside. The obtained lead compounds displayed significantly improved anticancer activity with dual mechanisms of cell death via apoptosis and autophagy, offering a fresh perspective to searching for new anticancer candidates.

International audience; A series of nitrogen heterocycles containing α-ethoxyphenylpropionic acid derivatives were designed as dual PPARα/γ agonist ligands for the treatment of type 2 diabetes (T2D) and its complications. 6-Benzoyl-benzothiazol-2-one was the most tolerant of the tested heterocycles in which incorporation of O-methyl oxime ether and trifluoroethoxy group followed by enantiomeric resolution led to the (S)-stereoisomer 44 b displaying the best in vitro pharmacological profile. Compound 44 b acted as a very potent full PPARγ agonist and a weak partial agonist on the PPARα receptor subtype. Compound 44 b showed high efficacy in an ob/ob mice model with significant decreases in serum triglyceride, glucose and insulin levels but mostly with limited body-weight gain and could be considered as a selective PPARγ modulator (SPPARγM).

International audience; Cancer treatment by magneto-mechanical effect of particles (TMMEP) is a growing field of research. The principle of this technique is to apply a mechanical force on cancer cells in order to destroy them thanks to magnetic particles vibrations. For this purpose, magnetic particles are injected in the tumor or exposed to cancer cells and a low-frequency alternating magnetic field is applied. This therapeutic approach is quite new and a wide range of treatment parameters are explored to date, as described in the literature. This review explains the principle of the technique, summarizes the parameters used by the different groups and reports the main in vitro and in vivo results.

There is an urgent need to develop new therapeutic strategies to fight the emergence of multidrug resistant bacteria. Many antimicrobial peptides (AMPs) have been identified and characterized, but clinical translation has been limited partly due to their structural instability and degradability in physiological environments. The use of unnatural backbones leading to foldamers can generate peptidomimetics with improved properties and conformational stability. We recently reported the successful design of urea-based eukaryotic cell-penetrating foldamers (CPFs). Since cell-penetrating peptides and AMPs generally share many common features, we prepared new sequences derived from CPFs by varying the distribution of histidine- and arginine-type residues at the surface of the oligourea helix, and evaluated their activity on both Gram-positive and Gram-negative bacteria as well as on fungi. In addition, we prepared and tested new amphiphilic block cofoldamers consisting of an oligourea and a peptide segment whereby polar and charged residues are located in the peptide segment and more hydrophobic residues in the oligourea segment. Several foldamer sequences were found to display potent antibacterial activities even in the presence of 50% serum. Importantly, we show that these urea-based foldamers also possess promising antifungal properties.

Flavaglines, a family of compounds from plants used in traditional Chinese medicine, exhibit a broad range of biological effects, including anticancer, antiviral, cardioprotective, and anti-inflammatory activities. They exert their action by targeting the scaffold proteins called prohibitin-1 and -2 and the mRNA helicases eIF4A and DDX3. Flavaglines are densely functionalized cyclopenta[b]benzofurans that have attracted the attention of some of the most eminent organic chemists. This review provides an overview of the biosynthesis, total synthesis, and pharmacological activities of flavaglines, which have recently culminated with the entrance of a synthetic derivative, Zotatifin, into clinical trials against advanced refractory solid tumors, intolerant to standard treatments.

In order to improve the therapeutic effect of a pharmaceutical dosage form, the administration time must be planned and adapted to the circadian rhythm of the patient, which is referred to as chronotherapy.However, this synchronization requires administration times that are not comfortable for patients.In order to increase patient compliance, a medical strategy that consists in modifying the release profiles of active ingredients, has emerged in recent years.In this work, a prototype of an innovative dosage form is created to meet the patient's needs in terms of dosage and release kinetics.Indeed, polymer films containing reservoirs loaded with drugs and distributed at predefined positions, were rolled up and stabilized in a cylindrical geometry using an enzyme.The position of the reservoir defines the delay and the rate of release of the API into the dissolution medium.This prototype represents a biphasic release system and therefore ensures an immediate release of active ingredients ensuring a rapid therapeutic effect, followed by a delayed release depending on the number of layers covering the reservoir and prolonged depending on the properties of the polymeric matrix which are deeply studied in this work.This system also makes it possible to combine drugs of different natures and release them in a controlled manner., Afin d’améliorer l’effet thérapeutique d’une forme de dosage pharmaceutique, le temps d’administration doit être planifié et adapté au rythme circadien du patient ce qu’on désigne par la chronothérapie. Néanmoins, cette synchronisation nécessite des temps d’administration qui ne sont pas confortables pour les patients. Afin d’augmenter la compliance du patient, une stratégie médicale qui consiste à modifier les profils de libération de principes actifs a émergé ces dernières années. Dans les travaux de cette thèse, un prototype d’une forme de dosage innovante est créé pour répondre aux besoins du patient en termes de dosage et de cinétique de libération. En effet, des films polymères contenant des réservoirs chargés de principes actifs et distribués à des positions prédéfinies, ont été enroulés et stabilisés dans une géométrie cylindrique à l’aide d’une enzyme. La position du réservoir, après la transformation de la distribution axiale en distribution radiale, définit le délai et le taux de libération du principe actif dans le milieu de dissolution.Ce prototype représente un système de relargage biphasique et assure donc une libération immédiate de principes actifs assurant un effet thérapeutique rapide, suivie d’une libération retardée selon le nombre de couches couvrant le réservoir et prolongée selon les propriétés de la matrice polymérique qui sont profondément étudiées dans ce travail de thèse. Ce système permet également de combiner des drugs de différentes natures et les libérer de façon contrôlée.

International audience; The pharmaceutical industry has a pervasive need for chiral specific molecules with optimal affinity for their biological targets. However, the mass production of such compounds is currently limited by conventional chemical routes, that are costly and have an environmental impact. Here, we propose an easy access to obtain new tetrahydroquinolines, a motif found in many bioactive compounds, that is rapid and cost effective. Starting from simple raw materials, the procedure uses a proline-catalyzed Mannich reaction followed by the addition of BF3.OEt2, which generates a highly electrophilic aza-ortho-quinone methide intermediate capable of reacting with different nucleophiles to form the diversely functionalized tetrahydroquinoline. Moreover, this enantioselective one-pot process provides access for the first time to tetrahydroquinolines with a cis-2,3 and trans-3,4 configuration. As proof of concept, we demonstrate that a three-step reaction sequence, from simple and inexpensive starting compounds and catalysts, can generate a BD2-selective BET bromodomain inhibitor with anti-inflammatory effect.

International audience; Toxoplasmosis is a major health issue worldwide especially for immune-deficient individuals and the offspring of newly infected mothers. It is caused by a unicellular intracellular parasite called Toxoplasma gondii. Although the drugs commonly used to treat toxoplasmosis are efficient, they present serious side effects and adverse events are common. Therefore, there is a need for the discovery of new compounds with potent anti-T. gondii activity. We have tested compounds designed to target enzymes that are involved in the epigenetic regulation of gene expression. Among the most active compounds, we identified an HDAC inhibitor that shows an IC 50 of around 30 nM with a selectivity index of more than 100. MC1742 is active at inhibiting the growth of the parasite in vitro but also at preventing the consequences of the acute disease in vivo. This compound induces hyper-acetylation of histones while acetylated tubulin level remains unchanged. After MC1742 treatment, the parasite expression profile is profoundly changed with the activation of genes preferentially expressed in the sexual stages that are normally repressed at the tachyzoite stage. These findings suggest that this compound disturbs the T. gondii gene expression program, inducing parasite death.

The dopamine receptor type 2 (D2R) is a G protein-coupled receptor (GPCR) specifically expressed in the central nervous system where it is largely involved in the control of several brain functions, including motivation, cognition or motor activity. Deregulations of the signaling pathways mediated by this receptor seem to be involved in the development of several psychiatric disorders such as depression, bipolar disorders, or schizophrenia. Despite their diversity, these disorders are accompanied by imbalances in lipid metabolism leading to a significant decrease in polyunsaturated fatty acid (PUFAs) levels. Although several clinical studies have reported the therapeutic potential of PUFAs supplementation for the reduction or prevention of certain psychiatric symptoms, the role of PUFAs in the alteration of dopaminergic transmission and the genesis of certain psychiatric diseases remains unknown. Thus, the hypothesis of this work is that PUFAs content in neuronal membranes expressing the D2R could influence the mechanisms of neurotransmission via a direct action on the pharmacology, the intracellular signaling, and the internalization of this receptor. In this context, the objective of this project was to evaluate the impact of membrane PUFAs on D2R internalization pathway. To unravel this, the receptor as well as all the proteins necessary to allow its internalization pathway have been expressed in mammalian cell system whose membrane PUFA composition has been enriched in a controlled manner. Lipidomic analysis confirmed the increase of PUFA content in total membranes of enriched cells. Then, Raman micro-spectroscopy was applied to determine the cellular distribution of exogenous fatty acid. Complementary techniques, confocal microscopy and time-resolved energy transfer, revealed a correlation between the membrane unsaturation level and D2R internalization efficacy. Interestingly, this correlation was not observed for another GPCR, the β2-adrenergic receptor, or by modulating the level of membrane saturated fatty acids (SFAs). Finally, TIRF microscopy was used to elucidate the impact of membrane lipid polyunsaturation on D2R membrane trafficking and β-arrestin recruitment, crucial for the initiation of D2R internalization. This study revealed a significant alteration in β-arrestin recruitment suggesting a causal link between membrane PUFAs level, β-arrestin recruitment, and D2R internalization. Thus, our data hold great promise for identifying the role of PUFAs in the genesis of psychiatric diseases., Le récepteur dopaminergique de type D2 (RD2) est un récepteur couplé à une protéine G (RCPG) majoritairement exprimé au niveau du système nerveux central où il est largement impliqué dans le contrôle de plusieurs fonctions cérébrales, dont la motivation, la cognition et la motricité fine. Des dérégulations des voies de signalisation médiées par le RD2 semblent être impliquées dans le développement de plusieurs pathologies psychiatriques telles que la dépression, les troubles bipolaires ou la schizophrénie. Bien que très différents, ces troubles ont notamment en commun une altération du métabolisme lipidique entrainant une diminution significative des taux en acides gras polyinsaturés (AGPI). Malgré le fait que plusieurs études cliniques ont rapporté le potentiel thérapeutique d’une supplémentation en AGPI pour la réduction voire la prévention de certains symptômes psychiatriques, le rôle des AGPI dans l’altération de la transmission dopaminergique et dans la genèse de certaines maladies psychiatriques demeure inconnu. Ainsi, l’hypothèse émise par notre équipe est que la composition en AGPI des membranes neuronales exprimant le RD2 pourrait influer sur les mécanismes de neurotransmission via une action directe sur la pharmacologie, la signalisation intracellulaire ainsi que l’internalisation de ce récepteur. Dans ce contexte, l’objectif de ce projet de thèse était d’évaluer l’impact des AGPI membranaires sur la voie d’internalisation du RD2. Ceci a été étudié par une approche in cellulo basée sur l’utilisation d’un système cellulaire, enrichi en AGPI d’intérêt, exprimant le RD2 humain ainsi que toutes les protéines nécessaires pour mimer sa voie d’internalisation. La réalisation d’analyses lipidomiques nous a permis, dans un premier temps, de nous assurer de l’augmentation de la teneur en AGPI dans les membranes totales des cellules enrichies. Ensuite, l’imagerie Raman a permis d’identifier la distribution cellulaire des acides gras d’intérêt. L’utilisation de cette approche cellulaire ainsi que des techniques complémentaires, la microscopie confocale et le transfert d’énergie en temps résolu, a révélé une corrélation entre le taux d’insaturation membranaire et la voie d’internalisation du RD2. D’une manière intéressante, cette corrélation n’était pas observable pour un autre RCPG de la même classe, le récepteur β2-adrénergique, ou en modulant le taux des acides gras saturés (AGS) membranaires. Dans un dernier temps, la microscopie TIRF a été utilisée pour élucider l’impact de l’enrichissement membranaire en AGPI sur le trafic membranaire du RD2 ainsi que sur le recrutement membranaire d’une protéine cytosolique, la β-arrestine, indispensable pour l’initiation de l’internalisation du RD2. Cette étude a mis en évidence une altération significative au niveau du recrutement de cette protéine cytosolique. Ainsi, cette observation suggère l’existence d’un lien causal entre le taux d’insaturation membranaire, le recrutement de la β-arrestine et l’internalisation du RD2. Nos données sont très prometteuses pour l’identification du rôle des AGPI dans la genèse des maladies psychiatriques.

Hypericum lanceolatum Lam. (H. lanceolatum) is a traditional medicinal plant from Reunion Island used for its pleiotropic effects mainly related to its antioxidant activity. The present work aimed to 1) determine the potential toxicity of the plant aqueous extract in vivo and 2) investigate its putative biological properties using several zebrafish models of oxidative stress, regeneration, estrogenicity, neurogenesis and metabolic disorders. First, we characterized the polyphenolic composition by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and identified chlorogenic acid isomers, quercetin and kaempferol derivatives as the major compounds. We then evaluated for the first time the toxicity of an aqueous extract of H. lanceolatum and determined a maximum non-toxic concentration (MNTC) in zebrafish eleutheroembryos from 0 to 96 hpf following OECD (Organization for Economic Cooperation and Development) guidelines. This MNTC test was also determined on hatched eleutheroembryos after 2 days of treatment (from 3 to 5 dpf). In our study, the anti-estrogenic effects of H. lanceolatum are supported by the data from the EASZY assay. In a tail amputation model, we showed that H. lanceolatum at its MNTC displays antioxidant properties, favors immune cell recruitment and tissue regeneration. Our results also highlighted its beneficial effects in metabolic disorders. Indeed, H. lanceolatum efficiently reduces lipid accumulation and body mass index in overfed larva- and adult-models, respectively. In addition, we show that H. lanceolatum did not improve fasting blood glucose levels in a hyperglycemic zebrafish model but surprisingly inhibited neurogenesis impairment observed in diabetic conditions. In conclusion, our study highlights the antioxidant, pro-regenerative, anti-lipid accumulation and pro-neurogenic effects of H. lanceolatum in vivo and supports the use of this traditional medicinal plant as a potential alternative in the prevention and/or treatment of metabolic disorders.

A study of some commonly used anti-viral nucleotide analogs using quantum mechanical methods has been carried out. Specifically the binding of nucleoside triphosphates (NTPs derived from IDX-184, Ribavirin, Sofosbuvir, Remdesivir, Molnupiravir, Favipiravir, AZT, Alovudine, and some natural NTPs etc) base paired with nucleosides (cytosine, guanine, adenine) has been studied since the rate-limiting step of RNA synthesis involves nucleoside analog triphosphates in the formation of the RNA/RdRp complex. It is shown that the location of the frontier orbitals and their HOMO-LUMO (HL) gaps can be used to predict the stability of the nucleotide analogs as shown in IDX-184, AZT, Alovudine and Sofosbuvir etc, rather than notions of steric effects reported in the literature. The major effect determining stabilities are electrostatic effects from the orientation of the anionic TP groups when the nucleotide analogs hydrogen bond with base pairs. The HL gaps and energies of the first excited states of NTP-nucleobase complexes can show which bases form more stable complexes, and which tautomeric form of the NTPs form the more stable complexes. The influence of how various substituents on the ribose (ribofuranose) ring influence the interaction of nucleotide analogs (eg IDX-184, Ribavirin, Sofosbuvir, Remdesivir, Molnupiravir, Favipiravir, AZT, Alovudine) with RdRp is also demonstrated. It was shown that Sofosbuvir has unique features amongst these drugs. These factors can be useful in design of more effective anti-viral drugs.

International audience; The last two decades have witnessed the rise in power of chemical protein synthesis to the point where it now constitutes an established corpus of synthetic methods efficiently complementing biological approaches. One factor explaining this spectacular evolution is the emergence of a new class of chemoselective reactions enabling the formation of native peptide bonds between two unprotected peptidic segments, also known as native ligation reactions. In recent years, their application has fueled the production of homogeneous batches of large and highly decorated protein targets with a control of their composition at the atomic level. In doing so, native ligation reactions have provided the means for successful applications in chemical biology, medicinal chemistry, materials science, and nanotechnology research.The native chemical ligation (NCL) reaction has had a major impact on the field by enabling the chemoselective formation of a native peptide bond between a C-terminal peptidyl thioester and an N-terminal cysteinyl peptide. Since its introduction in 1994, the NCL reaction has been made the object of significant improvements and its scope and limitations have been thoroughly investigated. Furthermore, the diversification of peptide segment assembly strategies has been essential to access proteins of increasing complexity and has had to overcome the challenge of controlling the reactivity of ligation partners.One hallmark of NCL is its dependency on thiol reactivity, including for its catalysis. While Nature constantly plays with the redox properties of biological thiols for the regulation of numerous biochemical pathways, such a control of reactivity is challenging to achieve in synthetic organic chemistry and, in particular, for those methods used for assembling peptide segments by chemical ligation. This Account covers the studies conducted by our group in this area. A leading theme of our research has been the conception of controllable acyl donors and cysteine surrogates that place the chemoselective formation of amide bonds by NCL-like reactions under the control of dichalcogenide-based redox systems. The dependency of the redox potential of dichalcogenide bonds on the nature of the chalcogenides involved (S, Se) has appeared as a powerful means for diversifying the systems, while allowing their sequential activation for protein synthesis. Such a control of reactivity mediated by the addition of harmless redox additives has greatly facilitated the modular and efficient preparation of multiple targets of biological relevance. Taken together, these endeavors provide a practical and robust set of methods to address synthetic challenges in chemical protein synthesis.

International audience; Malaria remains one of the major health problems worldwide. The increasing resistance of Plasmodium to approved antimalarial drugs requires the development of novel antiplasmodial agents that can effectively prevent and/or treat this disease. Based on the structure of Gamhepathiopine, a 2-tert-butylaminothieno[3,2-d]pyrimidin-4(3H)-one hit, active on the sexual and asexual stages of the parasite and thanked for the introduction of various substituents at position 4 of the thienopyrimidine core by nucleophilic aromatic substitution and pallado-catalyzed coupling reactions, a series of 4-substituted thieno[3,2-d]pyrimidines were identified as displaying in vitro activities against both the erythrocytic stage of P. falciparum and the hepatic stage of P. berghei. Among the 28 compounds evaluated, the chloro analogue of Gamhepathiopine showed good activity against the erythrocytic stage of P. falciparum, moderate toxicity on HepG2, and better activity against hepatic P. berghei parasites, compared to Gamhepathiopine.

International audience; This paper reports on the design of a series of 10 novel lipophilic piperazinyl derivatives of the 1-cyclopropyl-6-fluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, their synthesis, their characterisation by 1H, 13C and 19F NMR, IR spectroscopy and HRMS, as well as their biological activity against bacteria of medical interest. Among these derivatives, 2 were as potent as the parent quinolone against Neisseriagonorrhoeae whereas all the compounds displayed lower activity than the parent quinolone against other bacteria of medical interest. Our results showing that the increased lipophilicity was deleterious for antibacterial activity may help to design new quinolone derivatives in the future, especially lipophilic quinolones which have been poorly investigated previously.

Sugars are molecules present in many biological and physiological processes, such as cell-cell interactions and immune responses. Their great importance has earned them a certain interest in many research projects both in the methodology of organic synthesis and in the vast field of applications of glycosylated compounds. This thesis work is devoted to the study of the reactivity of thiosugars in the presence of transition metals for the synthesis of two types of compounds: O-heterosides and S-heterosides. O-heterosides (Chapter I) are synthesized from thiosugars and carboxylic acids by following a new and innovative method, based on a coupling catalyzed by Cu(acac)₂ and allowing the production of glycosidic esters in a stereoselective way in one very short time (15 minutes in the microwave). More than twenty products have been generated with yields ranging from 17 to 91%. The S-heterosides (Chapter II and III) are formed from thiosugars and iodinated aryls according to a palladocatalyzed coupling (Pd-Xantphos-G3) of Buchwald-Hartwig-Migita. The synthesized products were the subject of two subsequent applications. In the 2nd chapter, we were interested in chiral perfluorinated sulfoximines and their coupling to thiosugars in order to combine in the same structure : S-heteroside. The properties of the synthesized compounds have been studied and the diastereoisomers of all sulfoximine-thioglycosylated products have been successfully separated. Finally, in the 3rd chapter, we proceeded to the palladocatalyzed coupling of thiosugars and azobenzenes, known for their structurally reversible character in contact with light in order to form Azobenzene-thioglycosylated compounds. The studies carried out thereafter consist in evaluating the impact of the carbohydrate part on the azobenzene pattern by examining the photochromic and physicochemical properties (water solubility) of the Azobenzene-glycosylated compounds., Les sucres sont des molécules présentent dans de nombreux processus biologiques et physiologiques, tels que les interactions cellules-cellules et les réponses immunitaires. Leur grande importance leur a valu un intérêt certain dans beaucoup de projets de recherches tant dans la méthodologie de synthèse organique que dans le vaste domaine d’applications des composés glycosylés. Ce travail de thèse est consacré à l’étude de la réactivité des thiosucres en présence des métaux de transition pour la synthèse de deux types de composés : les O-hétérosides et les S-hétérosides. Les O-hétérosides (Chapitre I) sont synthétisés à partir de thiosucres et d’acides carboxyliques en suivant une méthode nouvelle et innovante, basée sur un couplage catalysé au Cu(acac)₂ et permettant de produire des esters glycosidiques de façon stéréosélective en un temps très court (15 minutes aux micro-ondes). Plus d’une vingtaines de produits ont été générés avec des rendements allant de 17 à 91%. Les S-hétérosides (Chapitre II et III) quant à eux, sont formés à partir de thiosucres et d’aryles iodés selon un couplage palladocatalysé (Pd-Xantphos-G3) de Buchwald-Hartwig-Migita. Les produits synthétisés ont fait l’objet de deux applications postérieures. Dans le 2ème chapitre, nous nous sommes intéressées aux sulfoximines perfluorées chirales et a leur couplage aux thiosucres afin de combiner les deux motifs dans une même structure de type S-hétérosides. Les propriétés des composés synthétisés ont été étudiés et les diastéréoisomères de tous les produits de type sulfoximines-thioglycosylées ont été séparés avec succés. Enfin, dans le 3ème chapitre, nous avons procédé au couplage palladocatalysé des thiosucres et des azobenzènes, connu pour leur caractère réversible structurellement au contact de la lumière afin de former des composés Azobenzènes-thioglycosylés. Les études réalisées par la suite consistent à évaluer l’impact de la partie glucidique sur le motif azobenzènes en examinant les propriétés photochromiques et physicochimiques (hydrosolubilité) des composés Azobenzènes-glycosylés.

International audience; New inhibitors of the bacterial tranferase MraY are described. Their structure is based on an aminoribosyl uridine scaffold, which is known to be important for the biological activity of natural MraY inhibitors. A decyl alkyl chain was introduced onto this scaffold through various linkers. The synthesized compounds were tested against the MraYAA transferase activity, and the most active compound with an original (S,S)-tartaric diamide linker inhibits MraY activity with an IC50 equal to 0.37 µM. Their antibacterial activity was also evaluated on a panel of Gram-positive and Gram-negative strains; however, the compounds showed no antibacterial activity. Docking and molecular dynamics studies revealed that this new linker established two stabilizing key interactions with N190 and H325, as observed for the highly potent inhibitors carbacaprazamycin, muraymycin D2 and tunicamycin.

International audience; N-selenoethyl cysteine (SetCys) in the form of its cyclic selenosulfide is a cysteine surrogate, whose reactivity depends on the reducing power of the medium. SetCys does not interfere with the native chemical ligation reaction under mild reducing conditions, that is in the absence of tris(2-carboxyethyl)phosphine (TCEP). In contrast, subjecting SetCys to TCEP results in the spontaneous loss of its N-selenoethyl appendage and thus to its conversion into a Cys residue. Therefore, SetCys can be used for the redox-controlled assembly of peptide segments using NCL. We provide in this protocol detailed procedures for the synthesis of Fmoc-protected SetCys residue and for its incorporation into peptides using standard solid-phase peptide synthesis protocols. We also describe its use for the chemical synthesis of proteins through the redox-controlled assembly of three peptide segments in one-pot.

International audience; The use of polypyridyl Ru complexes to inhibit metastasis is a novel approach, and recent studies have shown promising results. We have reported recently that Ru (II) complexes gathering two 4,7-diphenyl-1,10-phenanthroline (dip) ligands and the one being 2,2′-bipyridine (bpy) or its derivative with a 4-[3-(2-nitro-1H-imidazol-1-yl)propyl (bpy-NitroIm) or 5-(4-{4′-methyl-[2,2′-bipyridine]-4-yl}but-1-yn-1-yl)pyridine-2-carbaldehyde semicarbazone (bpy-SC) moieties can alter the metastatic cascade, among others, by modulating cell adhesion properties. In this work, we show further studies of this group of complexes by evaluating their effect on HMEC-1 endothelial cells. While all the tested complexes significantly inhibited the endothelial cell migration, Ru-bpy additionally interrupted the pseudovessels formation. Functional changes in endothelial cells might arise from the impact of the studied compounds on cell elasticity and expression of proteins (vinculin and paxillin) involved in focal adhesions. Furthermore, molecular studies showed that complexes modulate the expression of cell adhesion molecules, which has been suggested to be one of the factors that mediate the activation of angiogenesis. Based on the performed studies, we can conclude that the investigated polypyridyl Ru (II) complexes can deregulate the functionality of endothelial cells which may lead to the inhibition of angiogenesis.

Investigating biomolecular processes is challenging because of the intrinsic multi-scale hierarchical organization in system size and time in which chemical and chemical physical phenomena occur. Theoretical methods applied to biomolecules deals with the use of computation to obtain information about biological systems and their many interactions. The increasing accuracy of computational approaches and of computer architectures, allow to properly describe reaction paths involved in both activation/inhibition enzyme, calculate electronic properties and structural dynamics conformations of biomolecules without any limitation except those connected with the adopted theoretical protocol. Currently, computational biochemistry has predictive power and provides very insightful data that are sometimes tedious to obtain from experiment. In addition to the clarification of biochemical processes at the molecular and atomistic level, a very important application of biomolecular modeling is the guide of rational drug design process based on knowledge of a biological target (Computer-Aided Drug Design). Molecular Dynamics (MD) methods based on classical Molecular Mechanics principles have improved notions of the dynamics of molecular systems and helped to move away from the unintentional rigidity imposed by crystallographic structural determination. Density Functional Theory (DFT) is a widely used theoretical method for carrying out quantum calculations in chemistry and biology research. With DFT, chemical processes involving electron reorganization such as charge transfer or formation/cleavage of covalent bonds can addressed in more reasonable computation times than a few decades ago. Nowadays, systems encompassing up to thousands of atoms are amenable to computer simulations. Hybrid quantum/classical methods (QM/MM) are used for modeling large molecular systems. In this way, a smaller region of a larger system is treated with the most accurate QM methods, while environmental contributions are still accounted with simpler and faster MM calculations. The objective of this PhD thesis is to elucidate activation or inhibition mechanisms involved in enzyme activity by using multiscale and original computational approaches., Les processus biomoléculaires sont difficiles à étudier en raison de l'organisation hiérarchique multi-échelle intrinsèquement complexe dans laquelle ils se produisent. Les méthodes théoriques sont désormais largement utilisées dans la compréhension des processus biochimiques. La précision croissante des approches computationnelles et des architectures informatiques permet de décrire correctement les voies de réaction impliquées dans les processus biologiques, sans beaucoup de limitations autres que celles strictement liées au protocole théorique adopté. La biochimie computationnelle a aujourd'hui un pouvoir prédictif et fournit des données très détaillées sur des processus difficiles à analyser expérimentalement. Une application très importante de la modélisation moléculaire est la conception rationnelle de médicaments basée sur la connaissance d'une cible biologique (conception de médicaments assistée par ordinateur). Les méthodes de dynamique moléculaire (MD) basées sur les principes classiques de la mécanique moléculaire ont permis d'améliorer les notions et de s'éloigner de la rigidité irréelle imposée par la détermination structurelle cristallographique. La théorie de la fonction de densité (DFT) est une méthode théorique largement utilisée pour effectuer des calculs quantiques dans la recherche biochimique. Avec la DFT, les processus chimiques impliquant une réorganisation des électrons, comme le transfert de charge ou la formation/rupture de liaisons covalentes, peuvent être traités dans des temps de calcul raisonnables. Aujourd'hui, des systèmes comprenant jusqu'à des milliers d'atomes sont étudiés par des simulations in silico. Des méthodes hybrides quantiques/classiques (QM/MM) sont en effet utilisées pour reproduire de grands systèmes moléculaires. Les approches QM/MM permettent de traiter une petite partie du système avec des méthodes de mécanique quantique et donc une très grande précision, tandis que les contributions du milieu environnant sont prises en compte avec des calculs MM plus simples et plus rapides. L'objectif de cette thèse est d'élucider les mécanismes d'activation et d'inhibition impliqués dans l'activité de certaines enzymes en utilisant des approches computationnelles multi-échelles originales.

International audience; Introduction: BACE-1 is an aspartate protease that is responsible for the proteolysis of amyloid precursor proteins into beta-amyloid (Aβ), a neurotoxic peptide in patients with Alzheimer’s disease (AD). As such, BACE-1 is a prime pharmacological target in the control of Aβ in the brain and its inhibition will be a sound approach in AD therapy. The majority of BACE 1 inhibitors in past and current clinical trials do not show significant selectivity for BACE 1 over BACE 2. Several BACE 1 inhibitors have been progressed into clinical trials, all of which unfortunately have been terminated due to toxicity and lack of efficacy. These limitations make that the β-Secretase (BACE 1 and BACE 2) enzimes could be two attractives drug target for the development of news BACE 1 selectivity inhibitors over BACE 2 in the AD. Methods: Quantitative structure activity relationship (QSAR) models were used for identification of selective potential inhibitors of BACE 1 protein. A dataset of 76 inhibitors collected from the literature with their IC50 being determined experimentally has been assembled. This dataset contains diverse compounds with different scaffolds and physical-chemical properties, covering a wide chemical space in the drug-like range. The alvaDesc 2.0.6 software was used with a series of molecular descriptors. The prediction of biological activities for a data set of 157 modified ribonucleotides is also presented. Results: The QSAR model for BACE 1 estimated that molecules with the following properties showed a positive contribution in the inhibitors activity: low value of frequency C-C at topological distance 3 and high values of molar refractivity, topological polar surface area using N, O, S, P polar contributions, octanol-water partition coefficient and a lead-like score drug-like indices. Besides, the QSAR model for the BACE 2 estimated that molecules with other properties as described below also increases the BACE 2 potency: a low value of sum of conventional bond orders (H-depleted), Quantitative Estimation of Drug-likeness (unweighted), high values of distance/detour ring index of order 6, and modified lead-like score (6 rules).Conclusions: The combined possibilities of quantum and physicochemical molecular descriptors, together with the Machine Learning techniques, allowed us to generate QSAR models, capable of discriminating between BACE 1 over BACE 2 inhibitors. QSAR models allowed the identification of five modified nucleotides as selective inhibitors against BACE 1 over BACE 2 in Alzheimer’s disease. Phosphate group in the selective modified nucleotides have a positive impact in the inhibitor’s activity. According the value of the significant molecular descriptors include in the QSAR models of BACE 1, a phosphate group in the molecule 156, the most active modificated ribonucleotide increases the BACE 1 inhibitor activity.