ABSTRACT
In this study, we identified antifolates with potent, targeted activity against whole-cell Mycobacterium tuberculosis (MTB). Liquid chromatography-mass spectrometry analysis of antifolate-treated cultures revealed metabolic disruption, including decreased pools of methionine and S-adenosylmethionine. Transcriptomic analysis highlighted altered regulation of genes involved in the biosynthesis and utilization of these two compounds. Supplementation with amino acids or S-adenosylmethionine was sufficient to rescue cultures from antifolate treatment. Instead of the "thymineless death" that characterizes folate pathway inhibition in a wide variety of organisms, these data suggest that MTB is vulnerable to a critical disruption of the reactions centered around S-adenosylmethionione, the activated methyl cycle.
Subject(s)
Antitubercular Agents/pharmacology , Folic Acid Antagonists/pharmacology , Folic Acid/metabolism , Methionine/analogs & derivatives , Methionine/metabolism , Mycobacterium tuberculosis/drug effects , Mycobacterium tuberculosis/metabolism , Dihydropteroate Synthase/antagonists & inhibitors , Drug Evaluation, Preclinical , Drug Synergism , Gene Expression Regulation, Bacterial/drug effects , Humans , Mycobacterium tuberculosis/enzymology , Mycobacterium tuberculosis/genetics , S-Adenosylmethionine/metabolism , Species Specificity , Tetrahydrofolate Dehydrogenase/metabolism , Triazines/pharmacologyABSTRACT
We report a new class of thiophene (TP) compounds that kill Mycobacterium tuberculosis by the previously uncharacterized mechanism of Pks13 inhibition. An F79S mutation near the catalytic Ser55 site in Pks13 conferred TP resistance in M. tuberculosis. Overexpression of wild-type Pks13 resulted in TP resistance, and overexpression of the Pks13(F79S) mutant conferred high resistance. In vitro, TP inhibited fatty acyl-AMP loading onto Pks13. TP inhibited mycolic acid biosynthesis in wild-type M. tuberculosis, but it did so to a much lesser extent in TP-resistant M. tuberculosis. TP treatment was bactericidal and equivalent to treatment with the first-line drug isoniazid, but it was less likely to permit emergent resistance. Combined isoniazid and TP treatment resulted in sterilizing activity. Computational docking identified a possible TP-binding groove within the Pks13 acyl carrier protein domain. This study confirms that M. tuberculosis Pks13 is required for mycolic acid biosynthesis, validates it as a druggable target and demonstrates the therapeutic potential of simultaneously inhibiting multiple targets in the same biosynthetic pathway.
Subject(s)
Antitubercular Agents/pharmacology , Bacterial Proteins/antagonists & inhibitors , Bacterial Proteins/metabolism , Mycobacterium tuberculosis/drug effects , Mycolic Acids/metabolism , Polyketide Synthases/antagonists & inhibitors , Polyketide Synthases/metabolism , Thiophenes/pharmacology , Antitubercular Agents/chemical synthesis , Antitubercular Agents/chemistry , Bacterial Proteins/genetics , Biocatalysis , Microbial Sensitivity Tests , Molecular Structure , Mutation , Mycobacterium tuberculosis/cytology , Mycobacterium tuberculosis/metabolism , Polyketide Synthases/genetics , Structure-Activity Relationship , Thiophenes/chemical synthesis , Thiophenes/chemistryABSTRACT
Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial and community-acquired pathogen for which few existing antibiotics are efficacious. Here we describe two structurally related synthetic compounds that potentiate beta-lactam activity against MRSA. Genetic studies indicate that these agents target SAV1754 based on the following observations: (i) it has a unique chemical hypersensitivity profile, (ii) overexpression or point mutations are sufficient to confer resistance, and (iii) genetic inactivation phenocopies the potentiating effect of these agents in combination with beta-lactams. Further, we demonstrate these agents inhibit peptidoglycan synthesis. Because SAV1754 is essential for growth and structurally related to the recently reported peptidoglycan flippase of Escherichia coli, we speculate it performs an analogous function in S. aureus. These results suggest that SAV1754 inhibitors might possess therapeutic potential alone, or in combination with beta-lactams to restore MRSA efficacy.
Subject(s)
Anti-Bacterial Agents/pharmacology , Carbapenems/pharmacology , Indoles/pharmacology , Methicillin-Resistant Staphylococcus aureus/drug effects , Peptidoglycan/chemistry , Piperidines/pharmacology , Anti-Bacterial Agents/chemistry , Carbapenems/chemistry , Drug Synergism , Indoles/chemistry , Methicillin-Resistant Staphylococcus aureus/genetics , Peptidoglycan/metabolism , Piperidines/chemistry , RNA Interference , RNA, Antisense/metabolismABSTRACT
3-Aryl-5-phenyl-(1,2,4)-triazoles were identified as selective inhibitors of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1). They are active in both in vitro and an in vivo mouse pharmacodynamic (PD) model. The synthesis and structure activity relationships are presented.
Subject(s)
11-beta-Hydroxysteroid Dehydrogenase Type 1/antagonists & inhibitors , Enzyme Inhibitors , Hydrocarbons, Aromatic , Hypoglycemic Agents , Metabolic Syndrome/drug therapy , Triazoles , Animals , Binding Sites , Disease Models, Animal , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacokinetics , Enzyme Inhibitors/therapeutic use , Hydrocarbons, Aromatic/chemical synthesis , Hydrocarbons, Aromatic/pharmacology , Hydrocarbons, Aromatic/therapeutic use , Hypoglycemic Agents/chemical synthesis , Hypoglycemic Agents/pharmacokinetics , Hypoglycemic Agents/therapeutic use , Inhibitory Concentration 50 , Mice , Models, Chemical , Structure-Activity Relationship , Triazoles/chemical synthesis , Triazoles/pharmacology , Triazoles/therapeutic useABSTRACT
A urea class of high affinity niacin receptor agonists was discovered. Compound 1a displayed good PK, better in vivo efficacy in reducing FFA in mouse than niacin, and no vasodilation in a mouse model. Compound 1q demonstrated equal affinity to GPR109A as niacin.
Subject(s)
Niacin/pharmacology , Receptors, G-Protein-Coupled/agonists , Urea , Animals , Combinatorial Chemistry Techniques , Humans , Male , Mice , Models, Animal , Molecular Structure , Receptors, Nicotinic , Structure-Activity Relationship , Urea/analogs & derivatives , Urea/chemical synthesis , Urea/chemistry , Urea/pharmacokinetics , Vasodilation/drug effectsABSTRACT
Adamantyl triazoles were identified as selective inhibitors of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1). They are active both in in vitro and in in vivo pharmacodynamic models. The synthesis and structure-activity relationships of these inhibitors are presented.
