ABSTRACT
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
Gram-negative bacteria lacking heptoses in their lipopolysaccharide (LPS) display attenuated virulence and increased sensitivity to human serum and to some antibiotics. Thus inhibition of bacterial heptose synthesis represents an attractive target for the development of new antibacterial agents. HldE is a bifunctional enzyme involved in the synthesis of bacterial heptoses. Development of a biochemical assay suitable for high-throughput screening allowed the discovery of inhibitors 1 and 2 of HldE kinase. Study of the structure-activity relationship of this series of inhibitors led to highly potent compounds.
