title: Deletion of fabN in Enterococcus faecalis results in unsaturated fatty acid auxotrophy and decreased release of inflammatory cytokines.
abstract: The Gram-positive bacterium Enterococcus faecalis can cause life-threatening infections and is resistant to several commonly used antibiotics. The type II fatty acid pathway in bacteria is discussed as a potential target for antimicrobial therapy. However, it was shown that inhibition or deletion of its enzymes can be rescued in Gram-positive bacteria by supplementation with fatty acids. Here we show that by deletion of the fabN gene, which is essential for unsaturated fatty acid (UFA) synthesis in E. faecalis, growth is impaired but can be rescued by supplementation with oleic acid or human serum. Nonetheless, we demonstrate alterations of the UFA profile after supplementation with oleic acid in the ΔfabN mutant using a specific glycolipid. In addition, we demonstrate that cytokine release in vitro is almost abolished after stimulation of mouse macrophages by the mutant in comparison to the wild type. The results indicate that fabN is not a suitable target for antimicrobials as UFA auxotrophy can be overcome. However, deletion of fabN resulted in a decreased inflammatory response indicating that fabN and resulting UFA synthesis are relevant for virulence.
authors.affiliation: Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany Division of Pediatric Infectious Diseases, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany Department of Microbiology, Faculty of Biology, Albert-Ludwigs-University, Freiburg, Germany.
authors.forename: Ann-Kristin
authors.initials: AK
authors.lastname: Diederich
authors.affiliation: Division of Structural Biochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Priority Area Asthma & Allergy, Research Center Borstel, Airway Research Center North (ARCN), Member of the German Center for Lung Research (DZL), D-23845 Borstel, Germany.
authors.forename: Katarzyna A
authors.initials: KA
authors.lastname: Duda
authors.affiliation: Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany 2EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France.
authors.forename: Felipe
authors.initials: F
authors.lastname: Romero-Saavedra
authors.affiliation: Division of Structural Biochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Priority Area Asthma & Allergy, Research Center Borstel, Airway Research Center North (ARCN), Member of the German Center for Lung Research (DZL), D-23845 Borstel, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Engel
authors.affiliation: Division of Structural Biochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Priority Area Asthma & Allergy, Research Center Borstel, Airway Research Center North (ARCN), Member of the German Center for Lung Research (DZL), D-23845 Borstel, Germany.
authors.forename: Otto
authors.initials: O
authors.lastname: Holst
authors.affiliation: Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany Division of Pediatric Infectious Diseases, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany johueb@gmail.com.
authors.forename: Johannes
authors.initials: J
authors.lastname: Huebner
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D048708:Cell Growth Processes / Q000235:genetics; D016207:Cytokines / Q000378:metabolism; D013293:Enterococcus faecalis / Q000502:physiology*; D054889:Fatty Acid Synthase, Type II / Q000235:genetics / Q000378:metabolism*; D016908:Gram-Positive Bacterial Infections / Q000276:immunology*; D006801:Humans; D006836:Hydro-Lyases / Q000235:genetics / Q000378:metabolism*; D007113:Immunity, Innate; D018836:Inflammation Mediators / Q000378:metabolism; D008264:Macrophages / Q000276:immunology* / Q000382:microbiology; D051379:Mice; D019301:Oleic Acid / Q000378:metabolism; D030781:Organisms, Genetically Modified; D000067996:RAW 264.7 Cells; D017384:Sequence Deletion / Q000235:genetics; D044967:Serum / Q000378:metabolism; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D016207:Cytokines; D018836:Inflammation Mediators; D019301:Oleic Acid; D006836:Hydro-Lyases; C047118:3-hydroxyacyl-(acyl-carrier-protein) dehydratase; D054889:Fatty Acid Synthase, Type II
keywords: Enterococcus faecalis; fabN; fatty acid uptake; unsaturated fatty acid auxotrophy; virulence