title: Glyoxylate detoxification is an essential function of malate synthase required for carbon assimilation inMycobacterium tuberculosis.
abstract: The glyoxylate shunt is a metabolic pathway of bacteria, fungi, and plants used to assimilate even-chain fatty acids (FAs) and has been implicated in persistence ofMycobacterium tuberculosis(Mtb). Recent work, however, showed that the first enzyme of the glyoxylate shunt, isocitrate lyase (ICL), may mediate survival ofMtbduring the acute and chronic phases of infection in mice through physiologic functions apart from fatty acid metabolism. Here, we report that malate synthase (MS), the second enzyme of the glyoxylate shunt, is essential for in vitro growth and survival ofMtbon even-chain fatty acids, in part, for a previously unrecognized activity: mitigating the toxicity of glyoxylate excess arising from metabolism of even-chain fatty acids. Metabolomic profiling revealed that MS-deficientMtbcultured on fatty acids accumulated high levels of the ICL aldehyde endproduct, glyoxylate, and increased levels of acetyl phosphate, acetoacetyl coenzyme A (acetoacetyl-CoA), butyryl CoA, acetoacetate, and β-hydroxybutyrate. These changes were indicative of a glyoxylate-induced state of oxaloacetate deficiency, acetate overload, and ketoacidosis. Reduction of intrabacterial glyoxylate levels using a chemical inhibitor of ICL restored growth of MS-deficientMtb, despite inhibiting entry of carbon into the glyoxylate shunt. In vivo depletion of MS resulted in sterilization ofMtbin both the acute and chronic phases of mouse infection. This work thus identifies glyoxylate detoxification as an essential physiologic function ofMtbmalate synthase and advances its validation as a target for drug development.
authors.affiliation: Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY 10021.
authors.forename: Susan
authors.initials: S
authors.lastname: Puckett
authors.affiliation: Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY 10021.
authors.forename: Carolina
authors.initials: C
authors.lastname: Trujillo
authors.affiliation: Department of Medicine, Weill Cornell Medical College, New York, NY 10021.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Medicine, Weill Cornell Medical College, New York, NY 10021.
authors.forename: Hyungjin
authors.initials: H
authors.lastname: Eoh
authors.affiliation: Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Ioerger
authors.affiliation: Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843.
authors.forename: Inna
authors.initials: I
authors.lastname: Krieger
authors.affiliation: Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843.
authors.forename: James
authors.initials: J
authors.lastname: Sacchettini
authors.affiliation: Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY 10021.
authors.forename: Dirk
authors.initials: D
authors.lastname: Schnappinger
authors.affiliation: Department of Medicine, Weill Cornell Medical College, New York, NY 10021; sae2004@med.cornell.edu kyr9001@med.cornell.edu.
authors.forename: Kyu Y
authors.initials: KY
authors.lastname: Rhee
authors.affiliation: Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY 10021; sae2004@med.cornell.edu kyr9001@med.cornell.edu.
authors.forename: Sabine
authors.initials: S
authors.lastname: Ehrt
mesh_terms: D000818:Animals; D002244:Carbon / Q000378:metabolism*; D004195:Disease Models, Animal; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D055786:Gene Knockout Techniques; D006038:Glyoxylates / Q000378:metabolism*; D008658:Inactivation, Metabolic; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D008292:Malate Synthase / Q000235:genetics / Q000378:metabolism*; D053858:Metabolic Networks and Pathways; D051379:Mice; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D014376:Tuberculosis / Q000188:drug therapy / Q000382:microbiology / Q000473:pathology; D014774:Virulence / Q000235:genetics
chemical_list: D005227:Fatty Acids; D006038:Glyoxylates; D002244:Carbon; D008292:Malate Synthase
keywords: glyoxylate detoxification; malate synthase; metabolism; tuberculosis