Targeting fatty acid biosynthesis for the development of novel chemotherapeutics against Mycobacterium tuberculosis: evaluation of A-ring-modified diphenyl ethers as high-affinity InhA inhibitors.
Structure-based design was used to develop a focused library of A-ring-modified diphenyl ether InhA inhibitors. From this library of analogs, two high-affinity alkyl-substituted diphenyl ethers, 6PP and 8PP, were selected for advanced study into their in vitro activity against Mycobacterium tuberculosis clinical isolates, their in vivo properties, and their signature response mode of action. 6PP and 8PP demonstrated enhanced activity against whole bacteria and showed activity in a rapid macrophage model of infection. In addition, transcriptional profiling revealed that the A-ring modifications of 6PP and 8PP increased the specificity of each analog for InhA. Both analogs had substantially longer half-lives in serum than did the parent compound, exhibited a fivefold reduction in cytotoxicity compared to the parent compound, and were well tolerated when administered orally at 300 mg/kg of body weight in animal models. Thus, the A-ring modifications increased the affinity and whole-cell specificity of the compounds for InhA and increased their bioavailability. The next step in optimization of the pharmacophore for preclinical evaluation is modification of the B ring to increase the bioavailability to that required for oral delivery.
Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA.
Melissa E
ME
Boyne
Todd J
TJ
Sullivan
Christopher W
CW
amEnde
Hao
H
Lu
Veronica
V
Gruppo
Darragh
D
Heaslip
Anita G
AG
Amin
Delphi
D
Chatterjee
Anne
A
Lenaerts
Peter J
PJ
Tonge
Richard A
RA
Slayden
D000818:Animals; D000995:Antitubercular Agents / Q000138:chemical synthesis* / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D001682:Biological Availability; D002470:Cell Survival / Q000187:drug effects; D002522:Chlorocebus aethiops; D016172:DNA Fingerprinting; D015195:Drug Design; D024881:Drug Resistance, Bacterial; D005227:Fatty Acids / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008264:Macrophages / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics; D010088:Oxidoreductases / Q000037:antagonists & inhibitors* / Q000235:genetics; D010587:Phagocytosis / Q000187:drug effects; D010647:Phenyl Ethers / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014158:Transcription, Genetic / Q000187:drug effects; D014260:Triclosan / Q000494:pharmacology; D014709:Vero Cells
D000995:Antitubercular Agents; D001426:Bacterial Proteins; D005227:Fatty Acids; D010647:Phenyl Ethers; C031538:phenyl ether; D014260:Triclosan; D010088:Oxidoreductases; C085257:InhA protein, Mycobacterium