Inhibitors of enzyme as anti-microbial drugsSUB1, a potential target for malaria treatment Metallo-β-lactamases, to fight the bacterial resistance to antibiotics

La résistance aux antimicrobiens est une menace majeure pour la santé publique. Pour tenter d'y répondre, deux études ont été réalisées au cours de ce travail. La première explorait une nouvelle cible pour lutter contre l'agent du paludisme et la seconde cherchait à combattre la résistance bactérienne à des antibiotiques.Le paludisme est la maladie parasitaire la plus meurtrière à travers le monde et, malgré des progrès importants, l'apparition de souches de Plasmodium falciparum résistantes à l'artémisinine fait craindre une perte de contrôle de l'épidémie. Par conséquent, la recherche de nouveaux antipaludiques constitue une priorité et il est primordial de s'attaquer à de nouvelles cibles impliquées dans plusieurs étapes clefs du cycle de vie du parasite. La peptidase SUB1, impliquée dans l'évasion hors des globules rouges et leur invasion, en est une. Ainsi, dans la première partie de ce manuscrit sont présentés les travaux consacrés au développement d'inhibiteurs potentiels de SUB1. Ces composés, basés sur les substrats naturels de SUB1 et son mécanisme catalytique, sont de nature pseudo-peptidique et contiennent une liaison α-céto-amide au niveau de la liaison scissile. Les travaux réalisés pour tenter d'améliorer le pouvoir inhibiteur et l'activité antiparasitaire en culture sont présentés.La menace d'un retour à l'ère pré-antibiotique est réelle à cause de la rapide dissémination de bactéries Gram-négatif multirésistantes aux antibiotiques. Un mode de résistance majeur est actuellement la production de métallo-β-lactamases (MBLs) capables d'inactiver les β-lactamines, et en particulier les carbapénèmes, antibiotiques de dernier recours à l'hôpital. Il est urgent de trouver une solution pour résoudre ce problème. La deuxième partie de ce manuscrit est ainsi consacrée au développement d'inhibiteurs de MBLs composés d'un motif 1,2,4-triazole-3-thione capable de coordiner simultanément les deux ions zinc du site actif de ces enzymes. Différentes séries d'analogues ont été préparées permettant d'explorer les substituants en positions 4 et 5 du motif. Les résultats des tests d'inhibition de MBLs représentatives et de tests sur souches cliniques résistantes sont également présentés.Antimicrobial resistance is a serious threat to global public health. To respond to this urgency, two studies were carried out during this work. The first one explored a new target to combat the agent of malaria and the second one seeked to fight the bacterial resistance to antibiotics.Malaria is the deadliest human parasitic disease worldwide. Despite important progresses, the emergence of multiresistant Plasmodium strains, including toward artemisinin, seriously threatens malaria treatment and control. Thus, the search for new drugs targeting essential steps of the parasite life cycle constitutes a priority. SUB1 is a promising drug target because it is involved in the egress of the merozoites from red blood cells and their invasion. The first part of this manuscript focuses on the development of potential SUB1 inhibitors. These compounds based on SUB1 natural substrates and its catalytic mechanism are pseudo-peptidic compounds containing an α-keto-amide bond in place of the scissile bond. The work carried out to improve the inhibitory potency and the antiparasitic activity in culture is presented.The threat of return to the pre-antibiotic era is real due to the rapid dissemination of multiresistant Gram-negative bacteria. One major mode of resistance is the production of metallo-β-lactamases (MBLs), able to inactivate the β-lactam antibiotics, in particular carbapenems, which are last-resort antibiotics at hospital. It is urgent to solve this problem. The second part of this manuscript is dedicated to the development of MBL inhibitors composed of a 1,2,4-triazole-3-thione scaffold, which simultaneously coordinates the two zinc ions present in the MBL active site. Several series of compounds have been prepared to explore the substituents at positions 4 and 5. The results of inhibition tests performed on representative MBLs and of microbiological tests are also presented

1,2,4-Triazole-3-thione compounds with a 4-ethyl alkyl/aryl sulfide substituent are broad-spectrum metallo-β-lactamase inhibitors with re-sensitization activity

Metallo-β-lactamases (MBLs) are important contributors of Gram-negative bacteria resistance to β-lactam antibiotics. MBLs are highly worrying because of their carbapenemase activity, their rapid spread in major human opportunistic pathogens while no clinically useful inhibitor is available yet. In this context, we are exploring the potential of compounds based on the 1,2,4-triazole-3-thione scaffold as an original ligand of the di-zinc active sites of MBLs, and diversely substituted at its positions 4 and 5. Here, we present a new series of compounds substituted at the 4-position by a thioether-containing alkyl chain with a carboxylic and/or an aryl group at its extremity. Several compounds showed broad-spectrum inhibition with Ki values in the μM to sub-μM range against VIM-type enzymes, NDM-1 and IMP-1. The presence of the sulfur and of the aryl group was important for the inhibitory activity and the binding mode of a few compounds in VIM-2 was revealed by X-ray crystallography. Importantly, in vitro antibacterial susceptibility assays showed that several inhibitors were able to potentiate the activity of meropenem on Klebsiella pneumoniae clinical isolates producing VIM-1 or VIM-4, with a potentiation effect of up to 16-fold. Finally, a selected compound was found to only moderately inhibit the di-zinc human glyoxalase II, and several showed no or only moderate toxicity toward several human cells, thus favourably completing a promising behaviour

1,2,4-Triazole-3-thione analogues with an arylakyl group at position 4 as metallo-β-lactamase inhibitors

International audienceMetallo-β-lactamases (MBLs) represent an increasingly serious threat to public health because of their increased prevalence worldwide in relevant opportunistic Gram-negative pathogens. MBLs efficiently inactivate widely used and most valuable β-lactam antibiotics, such as oxyiminocephalosporins (ceftriaxone, ceftazidime) and the last-resort carbapenems. To date, no MBL inhibitor has been approved for therapeutic applications. We are developing inhibitors characterized by a 1,2,4-triazole-3-thione scaffold as an original zinc ligand and few promising series were already reported. Here, we present the synthesis and evaluation of a new series of compounds characterized by the presence of an arylalkyl substituent at position 4 of the triazole ring. The alkyl link was mainly an ethylene, but a few compounds without alkyl or with an alkyl group of various lengths up to a butyl chain were also synthesized. Some compounds in both sub-series were micromolar to submicromolar inhibitors of tested VIM-type MBLs. A few of them were broad-spectrum inhibitors, as they showed significant inhibitory activity on NDM-1 and, to a lesser extent, IMP-1. Among these, several inhibitors were able to significantly reduce the meropenem MIC on VIM-1- and VIM-4- producing clinical isolates by up to 16-fold. In addition, ACE inhibition was absent or moderate and one promising compound did not show toxicity toward HeLa cells at concentrations up to 250 μM. This series represents a promising basis for further exploration. Finally, molecular modelling of representative compounds in complex with VIM-2 was performed to study their binding mode

1,2,4-Triazole-3-Thione Analogues with a 2-Ethylbenzoic Acid at Position 4 as VIM-type Metallo-β-Lactamase Inhibitors

peer reviewedMetallo-β-lactamases (MBLs) are increasingly involved as a major mechanism of resistance to carbapenems in relevant opportunistic Gram-negative pathogens. Unfortunately, clinically efficient MBL inhibitors still represent an unmet medical need. We previously reported several series of compounds based on the 1,2,4-triazole-3-thione scaffold. In particular, Schiff bases formed between diversely 5-substituted-4-amino com pounds and 2-carboxybenzaldehyde were broad-spectrum inhibitors of VIM-type, NDM-1 and IMP-1 MBLs. Unfortunately, these compounds were unable to restore antibiotic suscepti bility of MBL-producing bacteria, probably because of poor penetration and/or susceptibility to hydrolysis. To improve their microbiological activity, we synthesized and characterized compounds where the hydrazone-like bond of the Schiff base analogues was replaced by a stable ethyl link. This small change resulted in a narrower inhibition spectrum, as all compounds were poorly or not inhibiting NDM-1 and IMP-1, but showed a significantly better activity on VIM-type enzymes, with Ki values in the μM to sub-μM range. The resolution of the crystallo graphic structure of VIM-2 in complex with one of the best inhibitors yielded valuable information about their binding mode. Interestingly, several compounds were shown to restore the β-lactam susceptibility of VIM-type-producing E. coli labo ratory strains and also of K. pneumoniae clinical isolates. In addition, selected compounds were found to be devoid of toxicity toward human cancer cells at high concentration, thus showing promising safety

Optimization of 1,2,4-Triazole-3-thiones toward Broad-Spectrum Metallo-β-lactamase Inhibitors Showing Potent Synergistic Activity on VIM- and NDM-1-Producing Clinical Isolates

International audienceMetallo-β-lactamases (MBLs) contribute to the resistance of Gram-negative bacteria to carbapenems, last-resort antibiotics at hospital, and MBL inhibitors are urgently needed to preserve these important antibacterial drugs. Here, we describe a series of 1,2,4-triazole-3-thione-based inhibitors displaying an α-amino acid substituent, which amine was mono- or disubstituted by (hetero)aryl groups. Compounds disubstituted by certain nitrogen-containing heterocycles showed submicromolar activities against VIM-type enzymes and strong NDM-1 inhibition (Ki = 10-30 nM). Equilibrium dialysis, native mass spectrometry, isothermal calorimetry (ITC), and X-ray crystallography showed that the compounds inhibited both VIM-2 and NDM-1 at least partially by stripping the catalytic zinc ions. These inhibitors also displayed a very potent synergistic activity with meropenem (16- to 1000-fold minimum inhibitory concentration (MIC) reduction) against VIM-type- and NDM-1-producing ultraresistant clinical isolates, including Enterobacterales and Pseudomonas aeruginosa. Furthermore, selected compounds exhibited no or moderate toxicity toward HeLa cells, favorable absorption, distribution, metabolism, excretion (ADME) properties, and no or modest inhibition of several mammalian metalloenzymes

Optimization of 1,2,4-Triazole-3-thiones toward Broad-Spectrum Metallo-β-lactamase Inhibitors Showing Potent Synergistic Activity on VIM- and NDM-1-Producing Clinical Isolates.

peer reviewedMetallo-β-lactamases (MBLs) contribute to the resistance of Gram-negative bacteria to carbapenems, last-resort antibiotics at hospital, and MBL inhibitors are urgently needed to preserve these important antibacterial drugs. Here, we describe a series of 1,2,4-triazole-3-thione-based inhibitors displaying an α-amino acid substituent, which amine was mono- or disubstituted by (hetero)aryl groups. Compounds disubstituted by certain nitrogen-containing heterocycles showed submicromolar activities against VIM-type enzymes and strong NDM-1 inhibition (Ki = 10-30 nM). Equilibrium dialysis, native mass spectrometry, isothermal calorimetry (ITC), and X-ray crystallography showed that the compounds inhibited both VIM-2 and NDM-1 at least partially by stripping the catalytic zinc ions. These inhibitors also displayed a very potent synergistic activity with meropenem (16- to 1000-fold minimum inhibitory concentration (MIC) reduction) against VIM-type- and NDM-1-producing ultraresistant clinical isolates, including Enterobacterales and Pseudomonas aeruginosa. Furthermore, selected compounds exhibited no or moderate toxicity toward HeLa cells, favorable absorption, distribution, metabolism, excretion (ADME) properties, and no or modest inhibition of several mammalian metalloenzymes

Optimization of 1,2,4-Triazole-3-thiones toward Broad-Spectrum Metallo-β-lactamase Inhibitors Showing Potent Synergistic Activity on VIM- and NDM-1-Producing Clinical Isolates

Metallo-β-lactamases (MBLs) contribute to the resistance of Gram-negative bacteria to carbapenems, last-resort antibiotics at hospital, and MBL inhibitors are urgently needed to preserve these important antibacterial drugs. Here, we describe a series of 1,2,4-triazole-3-thione-based inhibitors displaying an α-amino acid substituent, which amine was mono- or disubstituted by (hetero)aryl groups. Compounds disubstituted by certain nitrogen-containing heterocycles showed submicromolar activities against VIM-type enzymes and strong NDM-1 inhibition (Ki = 10–30 nM). Equilibrium dialysis, native mass spectrometry, isothermal calorimetry (ITC), and X-ray crystallography showed that the compounds inhibited both VIM-2 and NDM-1 at least partially by stripping the catalytic zinc ions. These inhibitors also displayed a very potent synergistic activity with meropenem (16- to 1000-fold minimum inhibitory concentration (MIC) reduction) against VIM-type- and NDM-1-producing ultraresistant clinical isolates, including Enterobacterales and Pseudomonas aeruginosa. Furthermore, selected compounds exhibited no or moderate toxicity toward HeLa cells, favorable absorption, distribution, metabolism, excretion (ADME) properties, and no or modest inhibition of several mammalian metalloenzymes

Optimization of 1,2,4-Triazole-3-thiones toward Broad-Spectrum Metallo-β-lactamase Inhibitors Showing Potent Synergistic Activity on VIM- and NDM-1-Producing Clinical Isolates

Metallo-β-lactamases (MBLs) contribute to the resistance of Gram-negative bacteria to carbapenems, last-resort antibiotics at hospital, and MBL inhibitors are urgently needed to preserve these important antibacterial drugs. Here, we describe a series of 1,2,4-triazole-3-thione-based inhibitors displaying an α-amino acid substituent, which amine was mono- or disubstituted by (hetero)aryl groups. Compounds disubstituted by certain nitrogen-containing heterocycles showed submicromolar activities against VIM-type enzymes and strong NDM-1 inhibition (Ki = 10–30 nM). Equilibrium dialysis, native mass spectrometry, isothermal calorimetry (ITC), and X-ray crystallography showed that the compounds inhibited both VIM-2 and NDM-1 at least partially by stripping the catalytic zinc ions. These inhibitors also displayed a very potent synergistic activity with meropenem (16- to 1000-fold minimum inhibitory concentration (MIC) reduction) against VIM-type- and NDM-1-producing ultraresistant clinical isolates, including Enterobacterales and Pseudomonas aeruginosa. Furthermore, selected compounds exhibited no or moderate toxicity toward HeLa cells, favorable absorption, distribution, metabolism, excretion (ADME) properties, and no or modest inhibition of several mammalian metalloenzymes