ABSTRACT
In this paper, we present different strategies to vectorize HldE kinase inhibitors with the goal to improve their gram-negative intracellular concentration. Syntheses and biological effects of siderophoric, aminoglycosidic, amphoteric, and polycationic vectors are discussed. While siderophoric and amphoteric vectorization efforts proved to be disappointing in this series, aminoglycosidic and polycationic vectors were able for the first time to achieve synergistic effects of our inhibitors with erythromycin. Although these effects proved to be nonspecific, this study provides information about the required stereoelectronic arrangement of the polycationic amines and their basicity requirements to fulfill outer membrane destabilization resulting in better erythromycin synergies.
Subject(s)
Erythromycin/metabolism , Escherichia coli/metabolism , Multienzyme Complexes/antagonists & inhibitors , Nucleotidyltransferases/antagonists & inhibitors , Phosphotransferases (Alcohol Group Acceptor)/antagonists & inhibitors , Aminoglycosides/pharmacology , Anti-Bacterial Agents/metabolism , Erythromycin/chemistry , Erythromycin/pharmacology , Escherichia coli/drug effects , Lipopolysaccharides/biosynthesis , Microbial Sensitivity Tests , Multienzyme Complexes/drug effects , Nucleotidyltransferases/drug effects , Phosphotransferases (Alcohol Group Acceptor)/drug effects , Polyamines/pharmacology , PolyelectrolytesABSTRACT
We report here the optimization of an HldE kinase inhibitor to low nanomolar potency, which resulted in the identification of the first reported compounds active on selected E. coli strains. One of the most interesting candidates, compound 86, was shown to inhibit specifically bacterial LPS heptosylation on efflux pump deleted E. coli strains. This compound did not interfere with E. coli bacterial growth (MIC > 32 µg/mL) but sensitized this pathogen to hydrophobic antibiotics like macrolides normally inactive on Gram-negative bacteria. In addition, 86 could sensitize E. coli to serum complement killing. These results demonstrate that HldE kinase is a suitable target for drug discovery. They also pave the way toward novel possibilities of treating or preventing bloodstream infections caused by pathogenic Gram negative bacteria by inhibiting specific virulence factors.
Subject(s)
Anti-Bacterial Agents/chemical synthesis , Benzothiazoles/chemical synthesis , Escherichia coli/drug effects , Multienzyme Complexes/antagonists & inhibitors , Nucleotidyltransferases/antagonists & inhibitors , Phosphotransferases (Alcohol Group Acceptor)/antagonists & inhibitors , Triazines/chemical synthesis , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Benzothiazoles/chemistry , Benzothiazoles/pharmacology , Escherichia coli/pathogenicity , Lipopolysaccharides/pharmacology , Microbial Sensitivity Tests , Structure-Activity Relationship , Triazines/chemistry , Triazines/pharmacology , Virulence/drug effectsABSTRACT
In this paper, we present some elements of our optimization program to decouple triclosan's specific FabI effect from its nonspecific cytotoxic component. The implementation of this strategy delivered highly specific, potent, and nonbiocidal new FabI inhibitors. We also disclose some preclinical data of one of their representatives, 83, a novel antibacterial compound active against resistant staphylococci and some clinically relevant Gram negative bacteria that is currently undergoing clinical trials.
Subject(s)
Anti-Infective Agents, Local/pharmacology , Benzamides/pharmacology , Drug Resistance, Multiple, Bacterial/drug effects , Enoyl-(Acyl-Carrier-Protein) Reductase (NADH)/antagonists & inhibitors , Gram-Negative Bacteria/drug effects , Phenyl Ethers/pharmacology , Triclosan/pharmacology , Animals , Anti-Infective Agents, Local/chemical synthesis , Benzamides/chemical synthesis , Cells, Cultured , Dogs , Drug Evaluation, Preclinical , Humans , Microbial Sensitivity Tests , Models, Molecular , Molecular Structure , Phenyl Ethers/chemical synthesis , Rats , Structure-Activity Relationship , Triclosan/chemical synthesisABSTRACT
L-Heptoses (L-glycero-D-manno-heptopyranoses) are constituents of the inner core of lipolysaccharide (LPS), a molecule playing key roles in the mortality of many infectious diseases as well as in the virulence of many human pathogens. The inhibition of the first enzymes of the bacterial heptose biosynthetic pathway is an almost unexplored field to date although it appears to be a very novel way for the development of antivirulence drugs. We report the synthesis of a series of D-glycero-D-manno-heptopyranose 7-phosphate (H7P) analogues and their inhibition properties against the isomerase GmhA and the the kinase HldE, the two first enzymes of the bacterial heptose biosynthetic pathway. The heptose structures have been modified at the 1-, 2-, 6- and 7-positions to probe the importance of the key structural features of H7P that allow a tight binding to the target enzymes; H7P being the product of GmhA and the substrate of HldE, the second objective was to find structures that could simultaneously inhibit both enzymes. We found that GmhA and HldE were extremely sensitive to structural modifications at the 6- and 7- positions of the heptose scaffold. To our surprise, the epimeric analogue of H7P displaying a D-glucopyranose configuration was found to be the best inhibitor of both enzymes but also the only molecule of this series that could inhibit GmhA (IC(50)=34 µM) and HldE (IC(50)=9.4 µM) in the low micromolar range. Noteworthy, this study describes the first inhibitors of GmhA ever reported, and paves the way to the design of a second generation of molecules targeting the bacterial virulence.
Subject(s)
Bacterial Proteins/chemistry , Enzyme Inhibitors/chemistry , Escherichia coli/chemistry , Heptoses/biosynthesis , Heptoses/chemistry , Isomerases/chemistry , Lipopolysaccharides/biosynthesis , Lipopolysaccharides/chemistry , Phosphotransferases/chemistry , Bacterial Proteins/metabolism , Biosynthetic Pathways , Enzyme Inhibitors/pharmacology , Escherichia coli/enzymology , Escherichia coli/metabolism , Escherichia coli Proteins/chemistry , Escherichia coli Proteins/metabolism , Heptoses/metabolism , Humans , Isomerases/metabolism , Lipopolysaccharides/metabolism , Molecular Sequence Data , Molecular Structure , Phosphorylation , Phosphotransferases/metabolism , Stereoisomerism , VirulenceABSTRACT
A structure-activity relationship study from a screening hit and structure-based design strategy has led to the identification of bisarylureas as potent inhibitors of Streptococcus agalactiae Stk1. As this target has been directly linked to bacterial virulence, these inhibitors can be considered as a promising step towards antivirulence drugs.