title: Identification of pyruvate kinase in methicillin-resistant Staphylococcus aureus as a novel antimicrobial drug target.
abstract: Novel classes of antimicrobials are needed to address the challenge of multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA). Using the architecture of the MRSA interactome, we identified pyruvate kinase (PK) as a potential novel drug target based upon it being a highly connected, essential hub in the MRSA interactome. Structural modeling, including X-ray crystallography, revealed discrete features of PK in MRSA, which appeared suitable for the selective targeting of the bacterial enzyme. In silico library screening combined with functional enzymatic assays identified an acyl hydrazone-based compound (IS-130) as a potent MRSA PK inhibitor (50% inhibitory concentration [IC50] of 0.1 μM) with >1,000-fold selectivity over human PK isoforms. Medicinal chemistry around the IS-130 scaffold identified analogs that more potently and selectively inhibited MRSA PK enzymatic activity and S. aureus growth in vitro (MIC of 1 to 5 μg/ml). These novel anti-PK compounds were found to possess antistaphylococcal activity, including both MRSA and multidrug-resistant S. aureus (MDRSA) strains. These compounds also exhibited exceptional antibacterial activities against other Gram-positive genera, including enterococci and streptococci. PK lead compounds were found to be noncompetitive inhibitors and were bactericidal. In addition, mutants with significant increases in MICs were not isolated after 25 bacterial passages in culture, indicating that resistance may be slow to emerge. These findings validate the principles of network science as a powerful approach to identify novel antibacterial drug targets. They also provide a proof of principle, based upon PK in MRSA, for a research platform aimed at discovering and optimizing selective inhibitors of novel bacterial targets where human orthologs exist, as leads for anti-infective drug development.
authors.affiliation: Department of Medicine, Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Roya
authors.initials: R
authors.lastname: Zoraghi
authors.forename: Raymond H
authors.initials: RH
authors.lastname: See
authors.forename: Peter
authors.initials: P
authors.lastname: Axerio-Cilies
authors.forename: Nag S
authors.initials: NS
authors.lastname: Kumar
authors.forename: Huansheng
authors.initials: H
authors.lastname: Gong
authors.forename: Anne
authors.initials: A
authors.lastname: Moreau
authors.forename: Michael
authors.initials: M
authors.lastname: Hsing
authors.forename: Sukhbir
authors.initials: S
authors.lastname: Kaur
authors.forename: Richard D
authors.initials: RD
authors.lastname: Swayze
authors.forename: Liam
authors.initials: L
authors.lastname: Worrall
authors.forename: Emily
authors.initials: E
authors.lastname: Amandoron
authors.forename: Tian
authors.initials: T
authors.lastname: Lian
authors.forename: Linda
authors.initials: L
authors.lastname: Jackson
authors.forename: Jihong
authors.initials: J
authors.lastname: Jiang
authors.forename: Lisa
authors.initials: L
authors.lastname: Thorson
authors.forename: Christophe
authors.initials: C
authors.lastname: Labriere
authors.forename: Leonard
authors.initials: L
authors.lastname: Foster
authors.forename: Robert C
authors.initials: RC
authors.lastname: Brunham
authors.forename: William R
authors.initials: WR
authors.lastname: McMaster
authors.forename: B Brett
authors.initials: BB
authors.lastname: Finlay
authors.forename: Natalie C
authors.initials: NC
authors.lastname: Strynadka
authors.forename: Artem
authors.initials: A
authors.lastname: Cherkasov
authors.forename: Robert N
authors.initials: RN
authors.lastname: Young
authors.forename: Neil E
authors.initials: NE
authors.lastname: Reiner
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011770:Pyruvate Kinase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D000900:Anti-Bacterial Agents; D020033:Protein Isoforms; D011770:Pyruvate Kinase