title: Determining the mode of action of anti-mycobacterial C17 diyne natural products using expression profiling: evidence for fatty acid biosynthesis inhibition.
abstract: The treatment of microbial infections is becoming increasingly challenging because of limited therapeutic options and the growing number of pathogenic strains that are resistant to current antibiotics. There is an urgent need to identify molecules with novel modes of action to facilitate the development of new and more effective therapeutic agents. The anti-mycobacterial activity of the C17 diyne natural products falcarinol and panaxydol has been described previously; however, their mode of action remains largely undetermined in microbes. Gene expression profiling was therefore used to determine the transcriptomic response of Mycobacterium smegmatis upon treatment with falcarinol and panaxydol to better characterize the mode of action of these C17 diynes.
  
  
  
  Our analyses identified 704 and 907 transcripts that were differentially expressed in M. smegmatis after treatment with falcarinol and panaxydol respectively. Principal component analysis suggested that the C17 diynes exhibit a mode of action that is distinct to commonly used antimycobacterial drugs. Functional enrichment analysis and pathway enrichment analysis revealed that cell processes such as ectoine biosynthesis and cyclopropane-fatty-acyl-phospholipid synthesis were responsive to falcarinol and panaxydol treatment at the transcriptome level in M. smegmatis. The modes of action of the two C17 diynes were also predicted through Prediction of Activity Spectra of Substances (PASS). Based upon convergence of these three independent analyses, we hypothesize that the C17 diynes inhibit fatty acid biosynthesis, specifically phospholipid synthesis, in mycobacteria.
  
  
  
  Based on transcriptomic responses, it is suggested that the C17 diynes act differently than other anti-mycobacterial compounds in M. smegmatis, and do so by inhibiting phospholipid biosynthesis.
authors: Department of Biological Sciences, University of New Brunswick, PO Box 5050, 100 Tucker Park Road, E2L 4L5, Saint John, NB, Canada.
authors: Haoxin
authors: H
authors: Li
authors: Department of Biological Sciences, University of New Brunswick, PO Box 5050, 100 Tucker Park Road, E2L 4L5, Saint John, NB, Canada.
authors: Andrew
authors: A
authors: Cowie
authors: Department of Biological Sciences, University of New Brunswick, PO Box 5050, 100 Tucker Park Road, E2L 4L5, Saint John, NB, Canada.
authors: John A
authors: JA
authors: Johnson
authors: Department of Medicine, Division of Infectious Diseases, Saint John Regional Hospital, 400 University Ave, E2L 4L4, Saint John, NB, Canada.
authors: Duncan
authors: D
authors: Webster
authors: Department of Biological Sciences, University of New Brunswick, PO Box 5050, 100 Tucker Park Road, E2L 4L5, Saint John, NB, Canada.|Present address: Center for Environmental and Human Toxicology & Department of Physiological Sciences, UF Genetics Institute, College of Veterinary Medicine, University of Florida, 1333 Center Drive, 32610-0144, Gainesville, FL, USA.
authors: Christopher J
authors: CJ
authors: Martyniuk
authors: Department of Biological Sciences, University of New Brunswick, PO Box 5050, 100 Tucker Park Road, E2L 4L5, Saint John, NB, Canada. cgray@unb.ca.|Department of Chemistry, University of New Brunswick, PO Box 4400, 30 Dineen Drive, E3B 5A3, Fredericton, NB, Canada. cgray@unb.ca.
authors: Christopher A
authors: CA
authors: Gray
mesh_terms: D000599:Amino Acids, Diamino / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D000995:Antitubercular Agents / Q000737:chemistry / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D001688:Biological Products / Q000737:chemistry / Q000494:pharmacology*; D053280:Diynes / Q000737:chemistry / Q000494:pharmacology*; D005227:Fatty Acids / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D005233:Fatty Alcohols / Q000737:chemistry / Q000494:pharmacology*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D063990:Gene Ontology; D058977:Molecular Sequence Annotation; D020102:Mycobacterium smegmatis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D010743:Phospholipids / Q000096:biosynthesis; D025341:Principal Component Analysis; D012329:RNA, Bacterial / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D059467:Transcriptome
chemical_list: D000599:Amino Acids, Diamino; D000995:Antitubercular Agents; D001426:Bacterial Proteins; D001688:Biological Products; D053280:Diynes; D005227:Fatty Acids; D005233:Fatty Alcohols; D010743:Phospholipids; D012329:RNA, Bacterial; C018541:falcarinol; C055778:panaxydol; C045628:ectoine
keywords: Falcarinol; Gene network analysis; Mode of action; Mycobacterium smegmatis; Natural products; Panaxydol