Pyridone Methylsulfone Hydroxamate LpxC Inhibitors for the Treatment of Serious Gram-Negative Infections

Montgomery, Justin I.; Brown, Matthew F.; Reilly, Usa; Price, Loren M.; Abramite, J. A.; Arcari, Joel T.; Barham, Rose A.; Che, Ye; Chen, Jinshan Michael; Chung, Seok Won; Collantes, Elizabeth M.; Desbonnet, Charlene; Doroski, Matthew; Doty, Jonathan L.; Engtrakul, Juntyma J.; Harris, Thomas M.; Huband, Michael D.; Knafels, John D.; Leach, Karen L.; Liu, Shenping; Marfat, Anthony; McAllister, Laura A.; McElroy, Eric B.; Menard, Carol A.; Mitton‐Fry, Mark J.; Mullins, Lisa; Noe, Mark C.; O’Donnell, John P.; Oliver, Robert M.; Penzien, Joseph; Plummer, Mark S.; Shanmugasundaram, Veerabahu; Thoma, Christy L.; Tomaras, Andrew P.; Uccello, Daniel P.; Vaz, Alfin D. N.; Wishka, Donn G.

doi:10.1021/jm2014875

Cited by 91 publications

(90 citation statements)

References 24 publications

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“…The susceptibilities of these LpxH mutants did not change for control antibiotics, such as levofloxacin, meropenem, and tetracycline, indicating that the mechanism of resistance is specific to compound 1. Interestingly, these LpxH mutants also showed no change in susceptibility to the LpxC inhibitor PF1090, which targets an earlier step in the same pathway as that of LpxH (35). These results strongly suggest that this compound inhibits bacterial cell growth through inhibition of LpxH activity.…”

Section: Resultsmentioning

confidence: 87%

“…Overexpression of LpxH in an efflux mutant of E. coli abolished sensitivity to compound 1, further implicating LpxH as the target of this compound. Numerous inhibitors of LpxC, which performs the first committed step in this pathway, have been reported (29,35,45); however, none of these compounds have advanced beyond phase I clinical testing. To our knowledge, compound 1 is the first reported inhibitor of LpxH.…”

Section: Discussionmentioning

confidence: 99%

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Novel Antibacterial Targets and Compounds Revealed by a High-Throughput Cell Wall Reporter Assay

et al. 2015

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A high-throughput phenotypic screen based on a Citrobacter freundii AmpC reporter expressed in Escherichia coli was executed to discover novel inhibitors of bacterial cell wall synthesis, an attractive, well-validated target for antibiotic intervention. Here we describe the discovery and characterization of sulfonyl piperazine and pyrazole compounds, each with novel mechanisms of action. E. coli mutants resistant to these compounds display no cross-resistance to antibiotics of other classes. Resistance to the sulfonyl piperazine maps to LpxH, which catalyzes the fourth step in the synthesis of lipid A, the outer membrane anchor of lipopolysaccharide (LPS). To our knowledge, this compound is the first reported inhibitor of LpxH. Resistance to the pyrazole compound mapped to mutations in either LolC or LolE, components of the essential LolCDE transporter complex, which is required for trafficking of lipoproteins to the outer membrane. Biochemical experiments with E. coli spheroplasts showed that the pyrazole compound is capable of inhibiting the release of lipoproteins from the inner membrane. Both of these compounds have significant promise as chemical probes to further interrogate the potential of these novel cell wall components for antimicrobial therapy. IMPORTANCEThe prevalence of antibacterial resistance, particularly among Gram-negative organisms, signals a need for novel antibacterial agents. A phenotypic screen using AmpC as a sensor for compounds that inhibit processes involved in Gram-negative envelope biogenesis led to the identification of two novel inhibitors with unique mechanisms of action targeting Escherichia coli outer membrane biogenesis. One compound inhibits the transport system for lipoprotein transport to the outer membrane, while the other compound inhibits synthesis of lipopolysaccharide. These results indicate that it is still possible to uncover new compounds with intrinsic antibacterial activity that inhibit novel targets related to the cell envelope, suggesting that the Gram-negative cell envelope still has untapped potential for therapeutic intervention.

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Section: Resultsmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Novel Antibacterial Targets and Compounds Revealed by a High-Throughput Cell Wall Reporter Assay

et al. 2015

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“…2, A and B). In contrast to previous serendipitous observations of co-purified (25), Y. enterocolitica (green, PDB code 3nzk) (29), E. coli (red, PDB code 3p3g) (30), and P. aeruginosa (gray, PDB code 3uhm) (28). D, surface representation of E. coli LpxC with myr-UDP-GlcN.…”

Section: E Coli Lpxc Structure and Identification Of Bound Myr-udp-gmentioning

confidence: 80%

Structure of the Bacterial Deacetylase LpxC Bound to the Nucleotide Reaction Product Reveals Mechanisms of Oxyanion Stabilization and Proton Transfer

Clayton

Klein

Rickert

et al. 2013

Journal of Biological Chemistry

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Background: LpxC is a metal-dependent deacetylase essential for lipopolysaccharide biosynthesis. Results: The LpxC reaction product binds an extensive, conserved groove with the 2-amino group positioned in the active site. Conclusion: The product-bound LpxC structure reveals conserved ligand interactions and stabilization of a phosphate mimic of the oxyanion intermediate. Significance: LpxC structures are critical to elucidate the catalytic mechanism and design of novel antibiotics.

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“…In particular, the nine conserved Lpx enzymes are considered promising for the development of novel antibiotics, since (3-deoxy-D-manno-oct-2-ulosonic acid) 2 -lipid A (Kdo 2 -lipid A) is the minimal LPS structure that supports a functional outer membrane (OM) and cell viability for most Gram-negative bacteria (1,2). Indeed, the optimization of LpxC inhibitors has been an ongoing effort in antimicrobial research for over 2 decades, which has yielded compounds with impressive antibacterial activity against Gram-negative organisms such as Pseudomonas aeruginosa (1,(3)(4)(5)(6)(7)(8)(9). The identification of RJPXD33, an antimicrobial peptide that inhibits both Escherichia coli LpxA and LpxD, and a recently identified LpxH inhibitor suggests that other LPS biosynthetic steps could also be successfully targeted (10)(11)(12).…”

mentioning

confidence: 99%

Characterization of an Acinetobacter baumannii lptD Deletion Strain: Permeability Defects and Response to Inhibition of Lipopolysaccharide and Fatty Acid Biosynthesis

et al. 2016

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Lipid A on the Gram-negative outer membrane (OM) is synthesized in the cytoplasm by the Lpx pathway and translocated to the OM by the Lpt pathway. Some Acinetobacter baumannii strains can tolerate the complete loss of lipopolysaccharide (LPS) resulting from the inactivation of early LPS pathway genes such as lpxC. Here, we characterized a mutant deleted for lptD, which encodes an OM protein that mediates the final translocation of fully synthesized LPS to the OM. Cells lacking lptD had a growth defect comparable to that of an lpxC deletion mutant under the growth conditions tested but were more sensitive to hydrophobic antibiotics, revealing a more significant impact on cell permeability from impaired LPS translocation than from the loss of LPS synthesis. Consistent with this, ATP leakage and N-phenyl-1-naphthylamine (NPN) fluorescence assays indicated a more severe impact of lptD deletion than of lpxC deletion on inner and outer membrane permeability, respectively. Targeted In most Gram-negative bacteria, many of the proteins responsible for lipopolysaccharide (LPS) synthesis and transport are essential, making them potential targets for antibacterial drug development. In particular, the nine conserved Lpx enzymes are considered promising for the development of novel antibiotics, since (3-deoxy-D-manno-oct-2-ulosonic acid) 2 -lipid A (Kdo 2 -lipid A) is the minimal LPS structure that supports a functional outer membrane (OM) and cell viability for most Gram-negative bacteria (1, 2). Indeed, the optimization of LpxC inhibitors has been an ongoing effort in antimicrobial research for over 2 decades, which has yielded compounds with impressive antibacterial activity against Gram-negative organisms such as Pseudomonas aeruginosa (1,(3)(4)(5)(6)(7)(8)(9). The identification of RJPXD33, an antimicrobial peptide that inhibits both Escherichia coli LpxA and LpxD, and a recently identified LpxH inhibitor suggests that other LPS biosynthetic steps could also be successfully targeted (10-12). POL7001, a peptidomimetic antibiotic that inhibits LptD, the final essential step of the LPS transport (Lpt) system, has potent and specific antibacterial activity against P. aeruginosa, which, importantly, indicates that the LPS transport and OM assembly machinery may be attractive targets for antibacterial discovery (13)(14)(15).Acinetobacter baumannii is an emerging opportunistic bacterial pathogen of increasing concern due to multidrug resistance (16). A. baumannii is noted for its ability to develop resistance against most conventional antibiotics through mechanisms such as the upregulation of efflux pumps and horizontal transfer of resistance genes (17)(18)(19). Because of this, clinical resistance is becoming a serious issue for this organism (as well as for other Gram-negative pathogens), often necessitating the use of antibiotics of last resort, such as polymyxins (19,20). Understanding resistance to polymyxins, which are cationic and utilize LPS to gain access to cells, has therefore become a focus of renewed in-

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Pyridone Methylsulfone Hydroxamate LpxC Inhibitors for the Treatment of Serious Gram-Negative Infections

Cited by 91 publications

References 24 publications

Novel Antibacterial Targets and Compounds Revealed by a High-Throughput Cell Wall Reporter Assay

Novel Antibacterial Targets and Compounds Revealed by a High-Throughput Cell Wall Reporter Assay

Structure of the Bacterial Deacetylase LpxC Bound to the Nucleotide Reaction Product Reveals Mechanisms of Oxyanion Stabilization and Proton Transfer

Characterization of an Acinetobacter baumannii lptD Deletion Strain: Permeability Defects and Response to Inhibition of Lipopolysaccharide and Fatty Acid Biosynthesis

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