1
|
Mielniczuk S, Hoff K, Baselious F, Li Y, Haupenthal J, Kany AM, Riedner M, Rohde H, Rox K, Hirsch AKH, Krimm I, Sippl W, Holl R. Development of Fragment-Based Inhibitors of the Bacterial Deacetylase LpxC with Low Nanomolar Activity. J Med Chem 2024. [PMID: 39303295 DOI: 10.1021/acs.jmedchem.4c01262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2024]
Abstract
In a fragment-based approach using NMR spectroscopy, benzyloxyacetohydroxamic acid-derived inhibitors of the bacterial deacetylase LpxC bearing a substituent to target the uridine diphosphate-binding site of the enzyme were developed. By appending privileged fragments via a suitable linker, potent LpxC inhibitors with promising antibacterial activities could be obtained, like the one-digit nanomolar LpxC inhibitor (S)-13j [Ki (EcLpxC C63A) = 9.5 nM; Ki (PaLpxC): 5.6 nM]. To rationalize the observed structure-activity relationships, molecular docking and molecular dynamics studies were performed. Initial in vitro absorption-distribution-metabolism-excretion-toxicity (ADMET) studies of the most potent compounds have paved the way for multiparameter optimization of our newly developed isoserine-based amides.
Collapse
Affiliation(s)
- Sebastian Mielniczuk
- Institute of Organic Chemistry, Universität Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, 20146 Hamburg, Germany
| | - Katharina Hoff
- Institute of Organic Chemistry, Universität Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, 20146 Hamburg, Germany
| | - Fady Baselious
- Institute of Pharmacy, Martin-Luther-University of Halle-Wittenberg, Kurt-Mothes-Straße 3, 06120 Halle (Saale), Germany
| | - Yunqi Li
- Team "Small Molecules for Biological Targets", Institut Convergence Plascan, Centre de Recherche en Cancérologie de Lyon, INSERM U1052-CNRS UMR5286, Centre Léon Bérard, Université de Lyon, Université Claude Bernard Lyon1, 69008 Lyon, France
- Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences & School of Life Sciences, East China Normal University, 200241 Shanghai, China
| | - Jörg Haupenthal
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus E8.1, 66123 Saarbrücken, Germany
| | - Andreas M Kany
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus E8.1, 66123 Saarbrücken, Germany
| | - Maria Riedner
- Technology Platform Mass Spectrometry, Universität Hamburg, Mittelweg 177, 20148 Hamburg, Germany
| | - Holger Rohde
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, 20146 Hamburg, Germany
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Katharina Rox
- Department of Chemical Biology, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, 38124 Braunschweig, Germany
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, 38124 Braunschweig, Germany
| | - Anna K H Hirsch
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus E8.1, 66123 Saarbrücken, Germany
- Helmholtz International Lab for Anti-infectives, Campus E8.1, 66123 Saarbrücken, Germany
- Department of Pharmacy, Saarland University, Campus E8.1, 66123 Saarbrücken, Germany
| | - Isabelle Krimm
- Team "Small Molecules for Biological Targets", Institut Convergence Plascan, Centre de Recherche en Cancérologie de Lyon, INSERM U1052-CNRS UMR5286, Centre Léon Bérard, Université de Lyon, Université Claude Bernard Lyon1, 69008 Lyon, France
| | - Wolfgang Sippl
- Institute of Pharmacy, Martin-Luther-University of Halle-Wittenberg, Kurt-Mothes-Straße 3, 06120 Halle (Saale), Germany
| | - Ralph Holl
- Institute of Organic Chemistry, Universität Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, 20146 Hamburg, Germany
| |
Collapse
|
2
|
Wang H, Ishchenko A, Skudlarek J, Shen P, Dzhekieva L, Painter RE, Chen YT, Bukhtiyarova M, Leithead A, Tracy R, Babaoglu K, Bahnck-Teets C, Buevich A, Cabalu TD, Labroli M, Lange H, Lei Y, Li W, Liu J, Mann PA, Meng T, Mitchell HJ, Mulhearn J, Scapin G, Sha D, Shaw AW, Si Q, Tong L, Wu C, Wu Z, Xiao JC, Xu M, Zhang LK, McKenney D, Miller RR, Black TA, Cooke A, Balibar CJ, Klein DJ, Raheem I, Walker SS. Cerastecins inhibit membrane lipooligosaccharide transport in drug-resistant Acinetobacter baumannii. Nat Microbiol 2024; 9:1244-1255. [PMID: 38649414 DOI: 10.1038/s41564-024-01667-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 03/06/2024] [Indexed: 04/25/2024]
Abstract
Carbapenem-resistant Acinetobacter baumannii infections have limited treatment options. Synthesis, transport and placement of lipopolysaccharide or lipooligosaccharide (LOS) in the outer membrane of Gram-negative bacteria are important for bacterial virulence and survival. Here we describe the cerastecins, inhibitors of the A. baumannii transporter MsbA, an LOS flippase. These molecules are potent and bactericidal against A. baumannii, including clinical carbapenem-resistant Acinetobacter baumannii isolates. Using cryo-electron microscopy and biochemical analysis, we show that the cerastecins adopt a serpentine configuration in the central vault of the MsbA dimer, stalling the enzyme and uncoupling ATP hydrolysis from substrate flipping. A derivative with optimized potency and pharmacokinetic properties showed efficacy in murine models of bloodstream or pulmonary A. baumannii infection. While resistance development is inevitable, targeting a clinically unexploited mechanism avoids existing antibiotic resistance mechanisms. Although clinical validation of LOS transport remains undetermined, the cerastecins may open a path to narrow-spectrum treatment modalities for important nosocomial infections.
Collapse
Affiliation(s)
- Hao Wang
- Merck & Co., Inc., West Point, PA, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Ying Lei
- Merck & Co., Inc., West Point, PA, USA
| | - Wei Li
- Merck & Co., Inc., West Point, PA, USA
| | - Jian Liu
- Merck & Co., Inc., West Point, PA, USA
| | | | - Tao Meng
- Merck & Co., Inc., Rahway, NJ, USA
| | | | | | | | - Deyou Sha
- Merck & Co., Inc., West Point, PA, USA
| | | | - Qian Si
- Merck & Co., Inc., West Point, PA, USA
| | - Ling Tong
- Merck & Co., Inc., West Point, PA, USA
| | | | - Zhe Wu
- Merck & Co., Inc., West Point, PA, USA
| | | | - Min Xu
- Merck & Co., Inc., West Point, PA, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
3
|
Möller AM, Vázquez-Hernández M, Kutscher B, Brysch R, Brückner S, Marino EC, Kleetz J, Senges CHR, Schäkermann S, Bandow JE, Narberhaus F. Common and varied molecular responses of Escherichia coli to five different inhibitors of the lipopolysaccharide biosynthetic enzyme LpxC. J Biol Chem 2024; 300:107143. [PMID: 38458396 PMCID: PMC10998244 DOI: 10.1016/j.jbc.2024.107143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 03/10/2024] Open
Abstract
A promising yet clinically unexploited antibiotic target in difficult-to-treat Gram-negative bacteria is LpxC, the key enzyme in the biosynthesis of lipopolysaccharides, which are the major constituents of the outer membrane. Despite the development of dozens of chemically diverse LpxC inhibitor molecules, it is essentially unknown how bacteria counteract LpxC inhibition. Our study provides comprehensive insights into the response against five different LpxC inhibitors. All compounds bound to purified LpxC from Escherichia coli. Treatment of E. coli with these compounds changed the cell shape and stabilized LpxC suggesting that FtsH-mediated proteolysis of the inactivated enzyme is impaired. LpxC inhibition sensitized E. coli to vancomycin and rifampin, which poorly cross the outer membrane of intact cells. Four of the five compounds led to an accumulation of lyso-phosphatidylethanolamine, a cleavage product of phosphatidylethanolamine, generated by the phospholipase PldA. The combined results suggested an imbalance in lipopolysaccharides and phospholipid biosynthesis, which was corroborated by the global proteome response to treatment with the LpxC inhibitors. Apart from LpxC itself, FabA and FabB responsible for the biosynthesis of unsaturated fatty acids were consistently induced. Upregulated compound-specific proteins are involved in various functional categories, such as stress reactions, nucleotide, or amino acid metabolism and quorum sensing. Our work shows that antibiotics targeting the same enzyme do not necessarily elicit identical cellular responses. Moreover, we find that the response of E. coli to LpxC inhibition is distinct from the previously reported response in Pseudomonas aeruginosa.
Collapse
Affiliation(s)
- Anna-Maria Möller
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | | | - Blanka Kutscher
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Raffael Brysch
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Simon Brückner
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Emily C Marino
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Julia Kleetz
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Christoph H R Senges
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Sina Schäkermann
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Julia E Bandow
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Franz Narberhaus
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany.
| |
Collapse
|
4
|
Lim AL, Miller BW, Lin Z, Fisher MA, Barrows LR, Haygood MG, Schmidt EW. Resistance mechanisms for Gram-negative bacteria-specific lipopeptides, turnercyclamycins, differ from that of colistin. Microbiol Spectr 2023; 11:e0230623. [PMID: 37882570 PMCID: PMC10714751 DOI: 10.1128/spectrum.02306-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 09/13/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE Bacterial resistance to antibiotics is a crisis. Acinetobacter baumannii is among the CDC urgent threat pathogens in part for this reason. Lipopeptides known as turnercyclamycins are produced by symbiotic bacteria that normally live in marine mollusks, where they may be involved in shaping their symbiotic niche. Turnercyclamycins killed Gram-negative pathogens including drug-resistant Acinetobacter, but how do the mechanisms of resistance compare to other lipopeptide drugs? Here, we define resistance from a truncation of MlaA, a protein involved in regulating bacterial membrane phospholipids. Intriguingly, this resistance mechanism only affected one turnercyclamycin variant, which differed only in two atoms in the lipid tail of the compounds. We could not obtain significant resistance to the second turnercyclamycin variant, which was also effective in an infection model. This study reveals an unexpected subtlety in resistance to lipopeptide antibiotics, which may be useful in the design and development of antibiotics to combat drug resistance.
Collapse
Affiliation(s)
- Albebson L. Lim
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Bailey W. Miller
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Zhenjian Lin
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Mark A. Fisher
- Department of Pathology and ARUP Laboratories, University of Utah, Salt Lake City, Utah, USA
| | - Louis R. Barrows
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, USA
| | - Margo G. Haygood
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Eric W. Schmidt
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| |
Collapse
|
5
|
Ostroumova OS, Efimova SS. Lipid-Centric Approaches in Combating Infectious Diseases: Antibacterials, Antifungals and Antivirals with Lipid-Associated Mechanisms of Action. Antibiotics (Basel) 2023; 12:1716. [PMID: 38136750 PMCID: PMC10741038 DOI: 10.3390/antibiotics12121716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/05/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
One of the global challenges of the 21st century is the increase in mortality from infectious diseases against the backdrop of the spread of antibiotic-resistant pathogenic microorganisms. In this regard, it is worth targeting antibacterials towards the membranes of pathogens that are quite conservative and not amenable to elimination. This review is an attempt to critically analyze the possibilities of targeting antimicrobial agents towards enzymes involved in pathogen lipid biosynthesis or towards bacterial, fungal, and viral lipid membranes, to increase the permeability via pore formation and to modulate the membranes' properties in a manner that makes them incompatible with the pathogen's life cycle. This review discusses the advantages and disadvantages of each approach in the search for highly effective but nontoxic antimicrobial agents. Examples of compounds with a proven molecular mechanism of action are presented, and the types of the most promising pharmacophores for further research and the improvement of the characteristics of antibiotics are discussed. The strategies that pathogens use for survival in terms of modulating the lipid composition and physical properties of the membrane, achieving a balance between resistance to antibiotics and the ability to facilitate all necessary transport and signaling processes, are also considered.
Collapse
Affiliation(s)
- Olga S. Ostroumova
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg 194064, Russia;
| | | |
Collapse
|
6
|
Sabnis A, Edwards AM. Lipopolysaccharide as an antibiotic target. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119507. [PMID: 37268022 DOI: 10.1016/j.bbamcr.2023.119507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 04/18/2023] [Accepted: 05/14/2023] [Indexed: 06/04/2023]
Abstract
Gram-negative bacteria, including Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii are amongst the highest priority drug-resistant pathogens, for which new antibiotics are urgently needed. Whilst antibiotic drug development is inherently challenging, this is particularly true for Gram-negative bacteria due to the presence of the outer membrane, a highly selective permeability barrier that prevents the ingress of several classes of antibiotic. This selectivity is largely due to an outer leaflet composed of the glycolipid lipopolysaccharide (LPS), which is essential for the viability of almost all Gram-negative bacteria. This essentiality, coupled with the conservation of the synthetic pathway across species and recent breakthroughs in our understanding of transport and membrane homeostasis has made LPS an attractive target for novel antibiotic drug development. Several different targets have been explored and small molecules developed that show promising activity in vitro. However, these endeavours have met limited success in clinical testing and the polymyxins, discovered more than 70 years ago, remain the only LPS-targeting drugs to enter the clinic thus far. In this review, we will discuss efforts to develop therapeutic inhibitors of LPS synthesis and transport and the reasons for limited success, and explore new developments in understanding polymyxin mode of action and the identification of new analogues with reduced toxicity and enhanced activity.
Collapse
Affiliation(s)
- Akshay Sabnis
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, Armstrong Rd, London SW7 2AZ, UK
| | - Andrew M Edwards
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, Armstrong Rd, London SW7 2AZ, UK.
| |
Collapse
|
7
|
Fivenson EM, Rohs PDA, Vettiger A, Sardis MF, Torres G, Forchoh A, Bernhardt TG. A role for the Gram-negative outer membrane in bacterial shape determination. Proc Natl Acad Sci U S A 2023; 120:e2301987120. [PMID: 37607228 PMCID: PMC10469335 DOI: 10.1073/pnas.2301987120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 07/21/2023] [Indexed: 08/24/2023] Open
Abstract
The cell envelope of Gram-negative bacteria consists of three distinct layers: the cytoplasmic membrane, a cell wall made of peptidoglycan (PG), and an asymmetric outer membrane (OM) composed of phospholipid in the inner leaflet and lipopolysaccharide (LPS) glycolipid in the outer leaflet. The PG layer has long been thought to be the major structural component of the envelope protecting cells from osmotic lysis and providing them with their characteristic shape. In recent years, the OM has also been shown to be a load-bearing layer of the cell surface that fortifies cells against internal turgor pressure. However, whether the OM also plays a role in morphogenesis has remained unclear. Here, we report that changes in LPS synthesis or modification predicted to strengthen the OM can suppress the growth and shape defects of Escherichia coli mutants with reduced activity in a conserved PG synthesis machine called the Rod complex (elongasome) that is responsible for cell elongation and shape determination. Evidence is presented that OM fortification in the shape mutants restores the ability of MreB cytoskeletal filaments to properly orient the synthesis of new cell wall material by the Rod complex. Our results are therefore consistent with a role for the OM in the propagation of rod shape during growth in addition to its well-known function as a diffusion barrier promoting the intrinsic antibiotic resistance of Gram-negative bacteria.
Collapse
Affiliation(s)
- Elayne M. Fivenson
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
| | - Patricia D. A. Rohs
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
| | - Andrea Vettiger
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
| | - Marios F. Sardis
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
| | - Grasiela Torres
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
| | - Alison Forchoh
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
| | - Thomas G. Bernhardt
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
- HHMI, Chevy Chase, MD20815
| |
Collapse
|
8
|
Qun T, Zhou T, Hao J, Wang C, Zhang K, Xu J, Wang X, Zhou W. Antibacterial activities of anthraquinones: structure-activity relationships and action mechanisms. RSC Med Chem 2023; 14:1446-1471. [PMID: 37593578 PMCID: PMC10429894 DOI: 10.1039/d3md00116d] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 05/24/2023] [Indexed: 08/19/2023] Open
Abstract
With the increasing prevalence of untreatable infections caused by antibiotic-resistant bacteria, the discovery of new drugs from natural products has become a hot research topic. The antibacterial activity of anthraquinones widely distributed in traditional Chinese medicine has attracted much attention. Herein, the structure and activity relationships (SARs) of anthraquinones as bacteriostatic agents are reviewed and elucidated. The substituents of anthraquinone and its derivatives are closely related to their antibacterial activities. The stronger the polarity of anthraquinone substituents is, the more potent the antibacterial effects appear. The presence of hydroxyl groups is not necessary for the antibacterial activity of hydroxyanthraquinone derivatives. Substitution of di-isopentenyl groups can improve the antibacterial activity of anthraquinone derivatives. The rigid plane structure of anthraquinone lowers its water solubility and results in the reduced activity. Meanwhile, the antibacterial mechanisms of anthraquinone and its analogs are explored, mainly including biofilm formation inhibition, destruction of the cell wall, endotoxin inhibition, inhibition of nucleic acid and protein synthesis, and blockage of energy metabolism and other substances.
Collapse
Affiliation(s)
- Tang Qun
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences 200241 Shanghai China
| | - Tiantian Zhou
- School of Chinese Materia Medica, Guangdong Pharmaceutical University 440113 Guangzhou China
| | - Jiongkai Hao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences 200241 Shanghai China
| | - Chunmei Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences 200241 Shanghai China
- Key laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai Research Institute, Chinese Academy of Agricultural Sciences Shanghai 200241 China
| | - Keyu Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences 200241 Shanghai China
- Key laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai Research Institute, Chinese Academy of Agricultural Sciences Shanghai 200241 China
| | - Jing Xu
- Huanghua Agricultural and Rural Development Bureau Bohai New Area 061100 Hebei China
| | - Xiaoyang Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences 200241 Shanghai China
- Key laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai Research Institute, Chinese Academy of Agricultural Sciences Shanghai 200241 China
| | - Wen Zhou
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences 200241 Shanghai China
- Key laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai Research Institute, Chinese Academy of Agricultural Sciences Shanghai 200241 China
| |
Collapse
|
9
|
Jia Y, Chen W, Tang R, Zhang J, Liu X, Dong R, Hu F, Jiang X. Multi-armed antibiotics for Gram-positive bacteria. Cell Host Microbe 2023; 31:1101-1110.e5. [PMID: 37442098 DOI: 10.1016/j.chom.2023.06.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 04/03/2023] [Accepted: 06/14/2023] [Indexed: 07/15/2023]
Abstract
Antibiotic resistance is a serious threat to public health. Here, we propose a multi-armed chemical scaffold (MACS) for antibiotic screening, which refers to multi-armed molecules (MAMs) consisting of a core unit and three or four arms, neither of which is active for pathogens. Based on a structure-activity relationship study of MAMs, we discover a class of multi-armed antibiotics (MAAs) with a core similar to ethylene (E), carbon atom (C), benzene (B), nitrogen atom (N), and triazine (T) and three or four 4-phenylbenzoic acid (PBA) arms, or a B core and three 4-vinylbenzoic acid (VBA) or 4-ethynylbenzoic acid (EBA) arms. They can selectively interact with Gram-positive bacteria and inhibit cell wall assembly by targeting the lipid carriers of cell wall biosynthesis. MAAs have excellent antibacterial activities against Gram-positive bacteria, including clinical multi-drug-resistant (MDR) isolates. Our study provides a chemical scaffold and identifies eight antibacterial lead compounds for the development of antibiotics.
Collapse
Affiliation(s)
- Yuexiao Jia
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Rd., Nanshan District, Shenzhen, Guangdong 518055, P.R. China; Institute of Biomedical Engineering and Health Sciences, School of Medical and Health Engineering, Changzhou University, Changzhou, Jiangsu 213164, P.R. China
| | - Wenwen Chen
- School of Biomedical Engineering, Shenzhen University Medical School, Shenzhen University, Shenzhen, Guangdong 518055, P.R. China
| | - Rongbing Tang
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Rd., Nanshan District, Shenzhen, Guangdong 518055, P.R. China
| | - Jiangjiang Zhang
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Rd., Nanshan District, Shenzhen, Guangdong 518055, P.R. China
| | - Xiaoyan Liu
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Rd., Nanshan District, Shenzhen, Guangdong 518055, P.R. China
| | - Ruihua Dong
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Rd., Nanshan District, Shenzhen, Guangdong 518055, P.R. China
| | - Fupin Hu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Xingyu Jiang
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Rd., Nanshan District, Shenzhen, Guangdong 518055, P.R. China.
| |
Collapse
|
10
|
Niu Z, Lei P, Wang Y, Wang J, Yang J, Zhang J. Small molecule LpxC inhibitors against gram-negative bacteria: Advances and future perspectives. Eur J Med Chem 2023; 253:115326. [PMID: 37023679 DOI: 10.1016/j.ejmech.2023.115326] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/18/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
Uridine diphosphate-3-O-(hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC) is a metalloenzyme with zinc ions as cofactors and is a key enzyme in the essential structural outer membrane lipid A synthesis commitment step of gram-negative bacteria. As LpxC is extremely homologous among different Gram-negative bacteria, it is conserved in almost all gram-negative bacteria, which makes LpxC a promising target. LpxC inhibitors have been reported extensively in recent years, such as PF-5081090 and CHIR-090 were found to have broad-spectrum antibiotic activity against P. aeruginosa and E. coli. They are mainly classified into hydroxamate inhibitors and non-hydroxamate inhibitors based on their structure, but no LpxC inhibitors have been marketed due to safety and activity issues. This review, therefore, focuses on small molecule inhibitors of LpxC against gram-negative pathogenic bacteria and covers recent advances in LpxC inhibitors, focusing on their structural optimization process, structure-activity relationships, and future directions, with the aim of providing ideas for the development of LpxC inhibitors and clinical research.
Collapse
|
11
|
Fivenson EM, Rohs PD, Vettiger A, Sardis MF, Torres G, Forchoh A, Bernhardt TG. A role for the Gram-negative outer membrane in bacterial shape determination. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.03.527047. [PMID: 36778245 PMCID: PMC9915748 DOI: 10.1101/2023.02.03.527047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The cell envelope of Gram-negative bacteria consists of three distinct layers: the cytoplasmic membrane, a cell wall made of peptidoglycan (PG), and an asymmetric outer membrane (OM) composed of phospholipid in the inner leaflet and lipopolysaccharide (LPS) glycolipid in the outer leaflet. The PG layer has long been thought to be the major structural component of the envelope protecting cells from osmotic lysis and providing them with their characteristic shape. In recent years, the OM has also been shown to be a load-bearing layer of the cell surface that fortifies cells against internal turgor pressure. However, whether the OM also plays a role in morphogenesis has remained unclear. Here, we report that changes in LPS synthesis or modification predicted to strengthen the OM can suppress the growth and shape defects of Escherichia coli mutants with reduced activity in a conserved PG synthesis machine called the Rod system (elongasome) that is responsible for cell elongation and shape determination. Evidence is presented that OM fortification in the shape mutants restores the ability of MreB cytoskeletal filaments to properly orient the synthesis of new cell wall material by the Rod system. Our results are therefore consistent with a role for the OM in the propagation of rod shape during growth in addition to its well-known function as a diffusion barrier promoting the intrinsic antibiotic resistance of Gram-negative bacteria. SIGNIFICANCE The cell wall has traditionally been thought to be the main structural determinant of the bacterial cell envelope that resists internal turgor and determines cell shape. However, the outer membrane (OM) has recently been shown to contribute to the mechanical strength of Gram-negative bacterial envelopes. Here, we demonstrate that changes to OM composition predicted to increase its load bearing capacity rescue the growth and shape defects of Escherichia coli mutants defective in the major cell wall synthesis machinery that determines rod shape. Our results therefore reveal a previously unappreciated role for the OM in bacterial shape determination in addition to its well-known function as a diffusion barrier that protects Gram-negative bacteria from external insults like antibiotics.
Collapse
Affiliation(s)
- Elayne M. Fivenson
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
| | - Patricia D.A. Rohs
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
| | - Andrea Vettiger
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
| | - Marios F. Sardis
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
| | - Grasiela Torres
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
| | - Alison Forchoh
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
| | - Thomas G. Bernhardt
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
- Howard Hughes Medical Institute, Boston, United States
| |
Collapse
|
12
|
Alkatheri AH, Yap PSX, Abushelaibi A, Lai KS, Cheng WH, Erin Lim SH. Microbial Genomics: Innovative Targets and Mechanisms. Antibiotics (Basel) 2023; 12:190. [PMID: 36830101 PMCID: PMC9951906 DOI: 10.3390/antibiotics12020190] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 01/18/2023] Open
Abstract
Multidrug resistance (MDR) has become an increasing threat to global health because bacteria can develop resistance to antibiotics over time. Scientists worldwide are searching for new approaches that go beyond traditional antibiotic discovery and development pipelines. Advances in genomics, however, opened up an unexplored therapeutic opportunity for the discovery of new antibacterial agents. Genomic approaches have been used to discover several novel antibiotics that target critical processes for bacterial growth and survival, including histidine kinases (HKs), LpxC, FabI, peptide deformylase (PDF), and aminoacyl-tRNA synthetases (AaRS). In this review, we will discuss the use of microbial genomics in the search for innovative and promising drug targets as well as the mechanisms of action for novel antimicrobial agents. We will also discuss future directions on how the utilization of the microbial genomics approach could improve the odds of antibiotic development having a more successful outcome.
Collapse
Affiliation(s)
- Asma Hussain Alkatheri
- Health Sciences Division, Abu Dhabi Women’s College, Higher Colleges of Technology, Abu Dhabi 41012, United Arab Emirates
| | - Polly Soo-Xi Yap
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor 47500, Malaysia
| | - Aisha Abushelaibi
- Office of Campus Director, Abu Dhabi Colleges, Higher Colleges of Technology, Abu Dhabi 41012, United Arab Emirates
| | - Kok-Song Lai
- Health Sciences Division, Abu Dhabi Women’s College, Higher Colleges of Technology, Abu Dhabi 41012, United Arab Emirates
| | - Wan-Hee Cheng
- Faculty of Health and Life Sciences, INTI International University, Persiaran Perdana BBN, Nilai 71800, Malaysia
| | - Swee-Hua Erin Lim
- Health Sciences Division, Abu Dhabi Women’s College, Higher Colleges of Technology, Abu Dhabi 41012, United Arab Emirates
| |
Collapse
|
13
|
Basak S, Li Y, Tao S, Daryaee F, Merino J, Gu C, Delker SL, Phan JN, Edwards TE, Walker SG, Tonge PJ. Structure-Kinetic Relationship Studies for the Development of Long Residence Time LpxC Inhibitors. J Med Chem 2022; 65:11854-11875. [PMID: 36037447 PMCID: PMC10182817 DOI: 10.1021/acs.jmedchem.2c00974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC) is a promising drug target in Gram-negative bacteria. Previously, we described a correlation between the residence time of inhibitors on Pseudomonas aeruginosa LpxC (paLpxC) and the post-antibiotic effect (PAE) caused by the inhibitors on the growth of P. aeruginosa. Given that drugs with prolonged activity following compound removal may have advantages in dosing regimens, we have explored the structure-kinetic relationship for paLpxC inhibition by analogues of the pyridone methylsulfone PF5081090 (1) originally developed by Pfizer. Several analogues have longer residence times on paLpxC than 1 (41 min) including PT913, which has a residence time of 124 min. PT913 also has a PAE of 4 h, extending the original correlation observed between residence time and PAE. Collectively, the studies provide a platform for the rational modulation of paLpxC inhibitor residence time and the potential development of antibacterial agents that cause prolonged suppression of bacterial growth.
Collapse
Affiliation(s)
- Sneha Basak
- Center for Advanced Study of Drug Action, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Yong Li
- Center for Advanced Study of Drug Action, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Suyuan Tao
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Fereidoon Daryaee
- Center for Advanced Study of Drug Action, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Jonathan Merino
- Center for Advanced Study of Drug Action, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Chendi Gu
- Center for Advanced Study of Drug Action, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | | | - Jenny N. Phan
- McGill University Montreal, Quebec H3A 0G4, Canada Canada
| | | | - Stephen G. Walker
- Department of Oral Biology and Pathology, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Peter J. Tonge
- Center for Advanced Study of Drug Action, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
- Department of Radiology, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, USA
| |
Collapse
|
14
|
Garcia-Vello P, Di Lorenzo F, Zucchetta D, Zamyatina A, De Castro C, Molinaro A. Lipopolysaccharide lipid A: A promising molecule for new immunity-based therapies and antibiotics. Pharmacol Ther 2022; 230:107970. [PMID: 34454000 DOI: 10.1016/j.pharmthera.2021.107970] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/24/2021] [Accepted: 07/22/2021] [Indexed: 12/15/2022]
Abstract
Lipopolysaccharides (LPS) are the main components of the external leaflet of the Gram-negative outer membrane and consist of three different moieties: lipid A, core oligosaccharide, and O-polysaccharide. The lipid A is a glucosamine disaccharide with different levels of acylation and phosphorylation, beside carrying, in certain cases, additional substituents on the sugar backbone. It is also the main immunostimulatory part of the LPS, as its recognition by the host immune system represents a fundamental event for detection of perilous microorganisms. Moreover, an uncontrolled immune response caused by a large amount of circulating LPS can lead to dramatic outcomes for human health, such as septic shock. The immunostimulant properties of an LPS incredibly vary depending on lipid A chemical structure, and for this reason, natural and synthetic variants of the lipid A are under study to develop new drugs that mimic or antagonise its natural effects. Here, we review past and recent findings on the lipid A as an antibiotic target and immune-therapeutic molecule, with a special attention on the crucial role of the chemical structure and its exploitation for conceiving novel strategies for treatment of several immune-related pathologies.
Collapse
Affiliation(s)
- Pilar Garcia-Vello
- Department of Chemical Sciences, University of Naples Federico II, Napoli, Italy.
| | - Flaviana Di Lorenzo
- Department of Chemical Sciences, University of Naples Federico II, Napoli, Italy
| | - Daniele Zucchetta
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Alla Zamyatina
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Cristina De Castro
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
| | - Antonio Molinaro
- Department of Chemical Sciences, University of Naples Federico II, Napoli, Italy.
| |
Collapse
|
15
|
Dreger A, Hoff K, Agoglitta O, Bülbül EF, Melesina J, Sippl W, Holl R. Synthesis, biological evaluation, and molecular docking studies of deoxygenated C-glycosides as LpxC inhibitors. Bioorg Chem 2021; 117:105403. [PMID: 34758434 DOI: 10.1016/j.bioorg.2021.105403] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/23/2021] [Accepted: 10/02/2021] [Indexed: 11/29/2022]
Abstract
The bacterial deacetylase LpxC is a promising target for the development of novel antibiotics being selectively active against Gram-negative bacteria. In chiral pool syntheses starting from d- and l-ribose, a series regio- and stereoisomeric monohydroxytetrahydrofuran derivatives was synthesized and tested for LpxC inhibitory and antibacterial activities. Molecular docking studies were performed to rationalize the obtained structure-activity relationships. The (2S,3R,5R)-configured 3-hydroxytetrahydrofuran derivative ent-8 ((2S,3R,5R)-N,3-Dihydroxy-5-(4-{[4-(morpholinomethyl)phenyl]ethynyl}phenyl)tetrahydrofuran-2-carboxamide) was found to be the most potent LpxC inhibitor (Ki = 3.5 µM) of the synthesized series of monohydroxytetrahydrofuran derivatives and to exhibit the highest antibacterial activity against E. coli BL21(DE3) and the D22 strain.
Collapse
Affiliation(s)
- Alexander Dreger
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany
| | - Katharina Hoff
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany
| | - Oriana Agoglitta
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany
| | - Emre F Bülbül
- Institute of Pharmacy, Martin-Luther-University of Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle (Saale), Germany
| | - Jelena Melesina
- Institute of Pharmacy, Martin-Luther-University of Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle (Saale), Germany
| | - Wolfgang Sippl
- Institute of Pharmacy, Martin-Luther-University of Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle (Saale), Germany
| | - Ralph Holl
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany.
| |
Collapse
|
16
|
Adaptive responses of Pseudomonas aeruginosa to treatment with antibiotics. Antimicrob Agents Chemother 2021; 66:e0087821. [PMID: 34748386 DOI: 10.1128/aac.00878-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pseudomonas aeruginosa is among the highest priority pathogens for drug development, because of its resistance to antibiotics, extraordinary adaptability, and persistence. Anti-pseudomonal research is strongly encouraged to address the acute scarcity of innovative antimicrobial lead structures. In an effort to understand the physiological response of P. aeruginosa to clinically relevant antibiotics, we investigated the proteome after exposure to ciprofloxacin, levofloxacin, rifampicin, gentamicin, tobramycin, azithromycin, tigecycline, polymyxin B, colistin, ceftazidime, meropenem, and piperacillin/tazobactam. We further investigated the response to CHIR-90, which represents a promising class of lipopolysaccharide biosynthesis inhibitors currently under evaluation. Radioactive pulse-labeling of newly synthesized proteins followed by 2D-PAGE was used to monitor the acute response of P. aeruginosa to antibiotic treatment. The proteomic profiles provide insights into the cellular defense strategies for each antibiotic. A mathematical comparison of these response profiles based on upregulated marker proteins revealed similarities of responses to antibiotics acting on the same target area. This study provides insights into the effects of commonly used antibiotics on P. aeruginosa and lays the foundation for the comparative analysis of the impact of novel compounds with precedented and unprecedented modes of action.
Collapse
|
17
|
Basu R, Wang N, Basak S, Daryaee F, Babar M, Allen EK, Walker SG, Haley JD, Tonge PJ. Impact of Target Turnover on the Translation of Drug-Target Residence Time to Time-Dependent Antibacterial Activity. ACS Infect Dis 2021; 7:2755-2763. [PMID: 34357770 DOI: 10.1021/acsinfecdis.1c00317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The translation of time-dependent drug-target occupancy to extended pharmacological activity at low drug concentration depends on factors such as target vulnerability and the rate of target turnover. Previously, we demonstrated that the postantibiotic effect (PAE) caused by inhibitors of bacterial drug targets could be used to assess target vulnerability, and that high levels of target vulnerability coupled with relatively low rates of target resynthesis resulted in a strong correlation between drug-target residence time and the PAE following compound washout. Although the residence time of inhibitors on UDP-3-O-acyl-N-acetylglucosamine deacetylase (LpxC) in Pseudomonas aeruginosa (paLpxC) results in significant PAE, inhibitors of the equivalent enzyme in Escherichia coli (ecLpxC) do not cause a PAE. Hyperactivity of the fatty acid biosynthesis enzyme FabZ or the inclusion of sub-MIC levels of azithromycin lead to the observation of a PAE for three inhibitors of ecLpxC. FabZ hyperactivity has been shown to stabilize ecLpxC, and using mass spectrometry, we demonstrate that the appearance of a PAE can be directly linked to a 3-fold increase in the stability of ecLpxC. These studies substantiate the importance of target turnover in time-dependent drug activity.
Collapse
Affiliation(s)
- Rajeswari Basu
- Center for Advanced Study of Drug Action, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
- Department of Chemistry, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
| | - Nan Wang
- Center for Advanced Study of Drug Action, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
- Department of Chemistry, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
| | - Sneha Basak
- Center for Advanced Study of Drug Action, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
- Department of Chemistry, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
| | - Fereidoon Daryaee
- Center for Advanced Study of Drug Action, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
- Department of Chemistry, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
| | - Mustufa Babar
- Department of Chemistry, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
| | - Eleanor K. Allen
- Department of Chemistry, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
| | - Stephen G. Walker
- Department of Oral Biology and Pathology, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
| | - John D. Haley
- Department of Pathology, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
| | - Peter J. Tonge
- Center for Advanced Study of Drug Action, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
- Department of Chemistry, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
- Department of Radiology, Stony Brook University, John S. Toll Drive, Stony Brook, New York 11794-3400, United States
| |
Collapse
|
18
|
Guest RL, Rutherford ST, Silhavy TJ. Border Control: Regulating LPS Biogenesis. Trends Microbiol 2021; 29:334-345. [PMID: 33036869 PMCID: PMC7969359 DOI: 10.1016/j.tim.2020.09.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/11/2020] [Accepted: 09/14/2020] [Indexed: 12/20/2022]
Abstract
The outer membrane (OM) is a defining feature of Gram-negative bacteria that serves as a permeability barrier and provides rigidity to the cell. Critical to OM function is establishing and maintaining an asymmetrical bilayer structure with phospholipids in the inner leaflet and the complex glycolipid lipopolysaccharide (LPS) in the outer leaflet. Cells ensure this asymmetry by regulating the biogenesis of lipid A, the conserved and essential anchor of LPS. Here we review the consequences of disrupting the regulatory components that control lipid A biogenesis, focusing on the rate-limiting step performed by LpxC. Dissection of these processes provides critical insights into bacterial physiology and potential new targets for antibiotics able to overcome rapidly spreading resistance mechanisms.
Collapse
Affiliation(s)
- Randi L Guest
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Steven T Rutherford
- Department of Infectious Diseases, Genentech Inc., South San Francisco, CA, USA
| | - Thomas J Silhavy
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
| |
Collapse
|
19
|
Chikada T, Kanai T, Hayashi M, Kasai T, Oshima T, Shiomi D. Direct Observation of Conversion From Walled Cells to Wall-Deficient L-Form and Vice Versa in Escherichia coli Indicates the Essentiality of the Outer Membrane for Proliferation of L-Form Cells. Front Microbiol 2021; 12:645965. [PMID: 33776978 PMCID: PMC7991099 DOI: 10.3389/fmicb.2021.645965] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 02/22/2021] [Indexed: 12/13/2022] Open
Abstract
Gram-negative bacteria such as Escherichia coli are surrounded by an outer membrane, which encloses a peptidoglycan layer. Even if thinner than in many Gram-positive bacteria, the peptidoglycan in E. coli allows cells to withstand turgor pressure in hypotonic medium. In hypertonic medium, E. coli treated with a cell wall synthesis inhibitor such as penicillin G form wall-deficient cells. These so-called L-form cells grow well under anaerobic conditions (i.e., in the absence of oxidative stress), becoming deformed and dividing as L-form. Upon removal of the inhibitor, they return to the walled rod-shaped state. Recently, the outer membrane was reported to provide rigidity to Gram-negative bacteria and to strengthen wall-deficient cells. However, it remains unclear why L-form cells need the outer membrane for growth. Using a microfluidic system, we found that, upon treatment with the outer membrane-disrupting drugs polymyxin B and polymyxin B nonapeptide or with the outer membrane synthesis inhibitor CHIR-090, the cells lysed during cell deformation and division, indicating that the outer membrane was important even in hypertonic medium. L-form cells could return to rod-shaped when trapped in a narrow space, but not in a wide space, likely due to insufficient physical force. Outer membrane rigidity could be compromised by lack of outer membrane proteins; Lpp, OmpA, or Pal. Deletion of lpp caused cells to lyse during cell deformation and cell division. In contrast, ompA and pal mutants could be deformed and return to small oval cells even when less physical force was exerted. These results strongly suggest that wall-deficient E. coli cells require a rigid outer membrane to survive, but not too rigid to prevent them from changing cell shape.
Collapse
Affiliation(s)
- Taiki Chikada
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Tomomi Kanai
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Masafumi Hayashi
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Taishi Kasai
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Taku Oshima
- Department of Biotechnology, Toyama Prefectural University, Toyama, Japan
| | - Daisuke Shiomi
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| |
Collapse
|
20
|
Troudi A, Pagès JM, Brunel JM. Chemical Highlights Supporting the Role of Lipid A in Efficient Biological Adaptation of Gram-Negative Bacteria to External Stresses. J Med Chem 2021; 64:1816-1834. [PMID: 33538159 DOI: 10.1021/acs.jmedchem.0c02185] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The outer membrane (OM) of Gram-negative bacteria provides an efficient barrier against external noxious compounds such as antimicrobial agents. Associated with drug target modification, it contributes to the overall failure of chemotherapy. In the complex OM architecture, Lipid A plays an essential role by anchoring the lipopolysaccharide in the membrane and ensuring the spatial organization between lipids, proteins, and sugars. Currently, the targets of almost all antibiotics are intracellularly located and require translocation across membranes. We report herein an integrated view of Lipid A synthesis, membrane assembly, a structure comparison at the molecular structure level of numerous Gram-negative bacterial species, as well as its recent use as a target for original antibacterial molecules. This review paves the way for a new vision of a key membrane component that acts during bacterial adaptation to environmental stresses and for the development of new weapons against microbial resistance to usual antibiotics.
Collapse
Affiliation(s)
- Azza Troudi
- UMR-MD1, U1261, Aix Marseille Université, INSERM, SSA, MCT, 13385 Marseille, France.,Laboratory of Microorganisms and Active Biomolecules, Department of Biology, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis 1008, Tunisia
| | - Jean Marie Pagès
- UMR-MD1, U1261, Aix Marseille Université, INSERM, SSA, MCT, 13385 Marseille, France
| | - Jean Michel Brunel
- UMR-MD1, U1261, Aix Marseille Université, INSERM, SSA, MCT, 13385 Marseille, France
| |
Collapse
|
21
|
Antibacterial activity of xylose-derived LpxC inhibitors - Synthesis, biological evaluation and molecular docking studies. Bioorg Chem 2020; 107:104603. [PMID: 33429229 DOI: 10.1016/j.bioorg.2020.104603] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 12/24/2020] [Indexed: 12/15/2022]
Abstract
LpxC inhibitors represent a promising class of novel antibiotics selectively combating Gram-negative bacteria. In chiral pool syntheses starting from D- and L-xylose, a series of four 2r,3c,4t-configured C-furanosidic LpxC inhibitors was obtained. The synthesized hydroxamic acids were tested for antibacterial and LpxC inhibitory activity, the acquired biological data were compared with those of previously synthesized C-furanosides, and molecular docking studies were performed to rationalize the observed structure-activity relationships. Additionally, bacterial uptake and susceptibility to efflux pump systems were investigated for the most promising stereoisomers.
Collapse
|
22
|
State of the Art in the Culture of the Human Microbiota: New Interests and Strategies. Clin Microbiol Rev 2020; 34:34/1/e00129-19. [PMID: 33115723 DOI: 10.1128/cmr.00129-19] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The last 5 years have seen a turning point in the study of the gut microbiota with a rebirth of culture-dependent approaches to study the gut microbiota. High-throughput methods have been developed to study bacterial diversity with culture conditions aimed at mimicking the gut environment by using rich media such as YCFA (yeast extract, casein hydrolysate, fatty acids) and Gifu anaerobic medium in an anaerobic workstation, as well as media enriched with rumen and blood and coculture, to mimic the symbiosis of the gut microbiota. Other culture conditions target phenotypic and metabolic features of bacterial species to facilitate their isolation. Preexisting technologies such as next-generation sequencing and flow cytometry have also been utilized to develop innovative methods to isolate previously uncultured bacteria or explore viability in samples of interest. These techniques have been applied to isolate CPR (Candidate Phyla Radiation) among other, more classic approaches. Methanogenic archaeal and fungal cultures present different challenges than bacterial cultures. Efforts to improve the available systems to grow archaea have been successful through coculture systems. For fungi that are more easily isolated from the human microbiota, the challenge resides in the identification of the isolates, which has been approached by applying matrix-assisted laser desorption ionization-time of flight mass spectrometry technology to fungi. Bacteriotherapy represents a nonnegligible avenue in the future of medicine to correct dysbiosis and improve health or response to therapy. Although great strides have been achieved in the last 5 years, efforts in bacterial culture need to be sustained to continue deciphering the dark matter of metagenomics, particularly CPR, and extend these methods to archaea and fungi.
Collapse
|
23
|
Synthesis and biological evaluation of triazolyl-substituted benzyloxyacetohydroxamic acids as LpxC inhibitors. Bioorg Med Chem 2020; 28:115529. [DOI: 10.1016/j.bmc.2020.115529] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 01/13/2023]
|
24
|
Hou F, Chang Y, Huang Z, Han N, Bin L, Deng H, Li Z, Pan Z, Ding L, Gao H, Yang R, Zhi F, Bi Y. Application of LpxC enzyme inhibitor to inhibit some fast-growing bacteria in human gut bacterial culturomics. BMC Microbiol 2019; 19:308. [PMID: 31888576 PMCID: PMC6937742 DOI: 10.1186/s12866-019-1681-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 12/11/2019] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Culturomics can ascertain traces of microorganisms to be cultivated using different strategies and identified by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry or 16S rDNA sequencing. However, to cater to all requirements of microorganisms and isolate as many species as possible, multiple culture conditions must be used, imposing a heavy workload. In addition, the fast-growing bacteria (e.g., Escherichia) surpass the slow-growing bacteria in culture by occupying space and using up nutrients. Besides, some bacteria (e.g., Pseudomonas) suppress others by secreting antibacterial metabolites, making it difficult to isolate bacteria with lower competence. Applying inhibitors to restrain fast-growing bacteria is one method to cultivate more bacterial species from human feces. RESULTS We applied CHIR-090, an LpxC enzyme inhibitor that has antibacterial activity against most Gram-negative bacteria, to culturomics of human fresh feces. The antibacterial activity of CHIR-090 was first assessed on five Gram-negative species of bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus vulgaris, and Bacteroides vulgatus), all of which are commonly isolated from the human gut. Then, we assessed suitable concentrations of the inhibitor. Finally, CHIR-090 was applied in blood culture bottles for bacterial cultivation. In total, 102 species from five samples were identified. Of these, we found one new species, two species not reported previously in the human gut, and 11 species not previously isolated from humans. CONCLUSIONS CHIR-090 can suppress E. coli, P. aeruginosa, K. pneumoniae, Pro. vulgaris, but not B. vulgatus. Compared with the non-inhibitor group, CHIR-090 increased bacteria isolation by 23.50%, including four species not reported in humans and one new species. Application of LpxC enzyme inhibitor in culturomics increased the number of species isolated from the human gut.
Collapse
Affiliation(s)
- Fengyi Hou
- Guangdong Provincial Key Laboratory of Gastroenterology, Institute of Gastroenterology of Guangdong Province, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yuxiao Chang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Zongyu Huang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Ni Han
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Lei Bin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Huimin Deng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Zhengchao Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Zhiyuan Pan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Lei Ding
- Shijitan Hospital, Capital Medical University, Beijing, China
| | - Hong Gao
- Shijitan Hospital, Capital Medical University, Beijing, China
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Fachao Zhi
- Guangdong Provincial Key Laboratory of Gastroenterology, Institute of Gastroenterology of Guangdong Province, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
| | - Yujing Bi
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
| |
Collapse
|
25
|
John CM, Feng D, Jarvis GA. Treatment of human challenge and MDR strains of Neisseria gonorrhoeae with LpxC inhibitors. J Antimicrob Chemother 2019; 73:2064-2071. [PMID: 29726994 DOI: 10.1093/jac/dky151] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 03/29/2018] [Indexed: 11/15/2022] Open
Abstract
Objectives Inhibitors of UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC), which catalyses the second step in the biosynthesis of lipid A, have been developed as potential antibiotics for Gram-negative infections. Our objectives were to determine the effect of LpxC inhibition on the in vitro survival and inflammatory potential of Neisseria gonorrhoeae. Methods Survival of four human challenge strains was determined after treatment with two LpxC inhibitors for 2 and 4 h. To confirm results from treatment and assess their anti-inflammatory effect, the expression of TNF-α by human THP-1 monocytic cells infected with bacteria in the presence of the LpxC inhibitors was quantified. Cytotoxicity of inhibitors for THP-1 cells was evaluated by release of lactate dehydrogenase. Survival of five MDR strains was determined after 2 h of treatment with an LpxC inhibitor and the effect of co-treatment on MICs of ceftriaxone and azithromycin was examined. Results The inhibitors had bactericidal activity against the four human challenge and five MDR strains with one compound exhibiting complete killing at ≥5 mg/L after either 2 or 4 h of treatment. Treatment of gonococci infecting THP-1 monocytic cells reduced the levels of TNF-α probably owing to reduced numbers of bacteria and a lower level of expression of lipooligosaccharide. Neither inhibitor exhibited cytotoxicity for THP-1 cells. The MIC of azithromycin was slightly lowered by sublethal treatment of two MDR strains with an LpxC inhibitor. Conclusions Our in vitro results demonstrated promising efficacy of LpxC inhibition of N. gonorrhoeae that warrants further investigation particularly owing to the rise in MDR gonorrhoea.
Collapse
Affiliation(s)
- Constance M John
- Center for Immunochemistry, Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA, USA.,Department of Laboratory Medicine, University of California, San Francisco, CA, USA
| | - Dongxiao Feng
- Center for Immunochemistry, Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA, USA
| | - Gary A Jarvis
- Center for Immunochemistry, Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA, USA.,Department of Laboratory Medicine, University of California, San Francisco, CA, USA
| |
Collapse
|
26
|
Dreger A, Kharwb O, Agoglitta O, Bülbül EF, Melesina J, Sippl W, Holl R. Chiral Pool Synthesis, Biological Evaluation and Molecular Docking Studies ofC‐Furanosidic LpxC Inhibitors. ChemMedChem 2019; 14:871-886. [DOI: 10.1002/cmdc.201900068] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Indexed: 01/15/2023]
Affiliation(s)
- Alexander Dreger
- Department of Chemistry, Institute of Organic ChemistryUniversity of Hamburg Martin-Luther-King Platz 6 20146 Hamburg Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems Germany
| | - Omar Kharwb
- Institute of Pharmaceutical and Medicinal ChemistryUniversity of Münster Corrensstr. 48 48149 Münster Germany
| | - Oriana Agoglitta
- Department of Chemistry, Institute of Organic ChemistryUniversity of Hamburg Martin-Luther-King Platz 6 20146 Hamburg Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems Germany
- NRW Graduate School of ChemistryUniversity of Münster Germany
| | - Emre F. Bülbül
- Institute of PharmacyMartin Luther University of Halle-Wittenberg Wolfgang-Langenbeck Str. 4 06120 Halle/Saale Germany
| | - Jelena Melesina
- Institute of PharmacyMartin Luther University of Halle-Wittenberg Wolfgang-Langenbeck Str. 4 06120 Halle/Saale Germany
| | - Wolfgang Sippl
- Institute of PharmacyMartin Luther University of Halle-Wittenberg Wolfgang-Langenbeck Str. 4 06120 Halle/Saale Germany
| | - Ralph Holl
- Department of Chemistry, Institute of Organic ChemistryUniversity of Hamburg Martin-Luther-King Platz 6 20146 Hamburg Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems Germany
| |
Collapse
|
27
|
Chen AY, Adamek RN, Dick BL, Credille CV, Morrison CN, Cohen SM. Targeting Metalloenzymes for Therapeutic Intervention. Chem Rev 2019; 119:1323-1455. [PMID: 30192523 PMCID: PMC6405328 DOI: 10.1021/acs.chemrev.8b00201] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Metalloenzymes are central to a wide range of essential biological activities, including nucleic acid modification, protein degradation, and many others. The role of metalloenzymes in these processes also makes them central for the progression of many diseases and, as such, makes metalloenzymes attractive targets for therapeutic intervention. Increasing awareness of the role metalloenzymes play in disease and their importance as a class of targets has amplified interest in the development of new strategies to develop inhibitors and ultimately useful drugs. In this Review, we provide a broad overview of several drug discovery efforts focused on metalloenzymes and attempt to map out the current landscape of high-value metalloenzyme targets.
Collapse
Affiliation(s)
- Allie Y Chen
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Rebecca N Adamek
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Benjamin L Dick
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Cy V Credille
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Christine N Morrison
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Seth M Cohen
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| |
Collapse
|
28
|
Disrupting Gram-Negative Bacterial Outer Membrane Biosynthesis through Inhibition of the Lipopolysaccharide Transporter MsbA. Antimicrob Agents Chemother 2018; 62:AAC.01142-18. [PMID: 30104274 DOI: 10.1128/aac.01142-18] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/04/2018] [Indexed: 12/24/2022] Open
Abstract
There is a critical need for new antibacterial strategies to counter the growing problem of antibiotic resistance. In Gram-negative bacteria, the outer membrane (OM) provides a protective barrier against antibiotics and other environmental insults. The outer leaflet of the outer membrane is primarily composed of lipopolysaccharide (LPS). Outer membrane biogenesis presents many potentially compelling drug targets as this pathway is absent in higher eukaryotes. Most proteins involved in LPS biosynthesis and transport are essential; however, few compounds have been identified that inhibit these proteins. The inner membrane ABC transporter MsbA carries out the first essential step in the trafficking of LPS to the outer membrane. We conducted a biochemical screen for inhibitors of MsbA and identified a series of quinoline compounds that kill Escherichia coli through inhibition of its ATPase and transport activity, with no loss of activity against clinical multidrug-resistant strains. Identification of these selective inhibitors indicates that MsbA is a viable target for new antibiotics, and the compounds we identified serve as useful tools to further probe the LPS transport pathway in Gram-negative bacteria.
Collapse
|
29
|
Lee PS, Lapointe G, Madera AM, Simmons RL, Xu W, Yifru A, Tjandra M, Karur S, Rico A, Thompson K, Bojkovic J, Xie L, Uehara K, Liu A, Shu W, Bellamacina C, McKenney D, Morris L, Tonn GR, Osborne C, Benton BM, McDowell L, Fu J, Sweeney ZK. Application of Virtual Screening to the Identification of New LpxC Inhibitor Chemotypes, Oxazolidinone and Isoxazoline. J Med Chem 2018; 61:9360-9370. [PMID: 30226381 DOI: 10.1021/acs.jmedchem.8b01287] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
This report summarizes the identification and synthesis of novel LpxC inhibitors aided by computational methods that leveraged numerous crystal structures. This effort led to the identification of oxazolidinone and isoxazoline inhibitors with potent in vitro activity against P. aeruginosa and other Gram-negative bacteria. Representative compound 13f demonstrated efficacy against P. aeruginosa in a mouse neutropenic thigh infection model. The antibacterial activity against K. pneumoniae could be potentiated by Gram-positive antibiotics rifampicin (RIF) and vancomycin (VAN) in both in vitro and in vivo models.
Collapse
Affiliation(s)
- Patrick S Lee
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Guillaume Lapointe
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Ann Marie Madera
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Robert L Simmons
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Wenjian Xu
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Aregahegn Yifru
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Meiliana Tjandra
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Subramanian Karur
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Alice Rico
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Katherine Thompson
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Jade Bojkovic
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Lili Xie
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Kyoko Uehara
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Amy Liu
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Wei Shu
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Cornelia Bellamacina
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - David McKenney
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Laura Morris
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - George R Tonn
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Colin Osborne
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Bret M Benton
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Laura McDowell
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Jiping Fu
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| | - Zachary K Sweeney
- Novartis Institutes for Biomedical Research , 5300 Chiron Way , Emeryville , California 94608 , United States
| |
Collapse
|
30
|
Ginsel C, Plitzko B, Froriep D, Stolfa DA, Jung M, Kubitza C, Scheidig AJ, Havemeyer A, Clement B. The Involvement of the Mitochondrial Amidoxime Reducing Component (mARC) in the Reductive Metabolism of Hydroxamic Acids. Drug Metab Dispos 2018; 46:1396-1402. [DOI: 10.1124/dmd.118.082453] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 07/11/2018] [Indexed: 12/18/2022] Open
|
31
|
Ahmad S, Navid A, Akhtar AS, Azam SS, Wadood A, Pérez-Sánchez H. Subtractive Genomics, Molecular Docking and Molecular Dynamics Simulation Revealed LpxC as a Potential Drug Target Against Multi-Drug Resistant Klebsiella pneumoniae. Interdiscip Sci 2018; 11:508-526. [PMID: 29721784 DOI: 10.1007/s12539-018-0299-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 04/11/2018] [Accepted: 04/24/2018] [Indexed: 12/17/2022]
Abstract
The emergence and dissemination of pan drug resistant clones of Klebsiella pneumoniae are great threat to public health. In this regard new therapeutic targets must be highlighted to pave the path for novel drug discovery and development. Subtractive proteomic pipeline brought forth UDP-3-O-[3-hydroxymyristoyl] N-acetylglucosamine deacetylase (LpxC), a Zn+2 dependent cytoplasmic metalloprotein and catalyze the rate limiting deacetylation step of lipid A biosynthesis pathway. Primary sequence analysis followed by 3-dimensional (3-D) structure elucidation of the protein led to the detection of K. pneumoniae LpxC (KpLpxC) topology distinct from its orthologous counterparts in other bacterial species. Molecular docking study of the protein recognized receptor antagonist compound 106, a uridine-based LpxC inhibitory compound, as a ligand best able to fit the binding pocket with a Gold Score of 67.53. Molecular dynamics simulation of docked KpLpxC revealed an alternate binding pattern of ligand in the active site. The ligand tail exhibited preferred binding to the domain I residues as opposed to the substrate binding hydrophobic channel of subdomain II, usually targeted by inhibitory compounds. Comparison with the undocked KpLpxC system demonstrated ligand induced high conformational changes in the hydrophobic channel of subdomain II in KpLpxC. Hence, ligand exerted its inhibitory potential by rendering the channel unstable for substrate binding.
Collapse
Affiliation(s)
- Sajjad Ahmad
- National Center for Bioinformatics (NCB), Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Afifa Navid
- National Center for Bioinformatics (NCB), Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Amina Saleem Akhtar
- National Center for Bioinformatics (NCB), Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Syed Sikander Azam
- National Center for Bioinformatics (NCB), Quaid-i-Azam University, Islamabad, 45320, Pakistan.
| | - Abdul Wadood
- Department of Biochemistry, Abdul Wali Khan University-Mardan, Shankar Campus, Mardan, Khyber Pukhtoonkhwa, Pakistan
| | - Horacio Pérez-Sánchez
- Structural Bioinformatics and High Performance Computing Research Group (BIO-HPC), Universidad Católica San Antonio de Murcia (UCAM), Murcia, Spain
| |
Collapse
|
32
|
Žalubovskis R, Winum JY. Inhibitors of Selected Bacterial Metalloenzymes. Curr Med Chem 2018; 26:2690-2714. [PMID: 29611472 DOI: 10.2174/0929867325666180403154018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 03/14/2018] [Accepted: 03/19/2018] [Indexed: 12/26/2022]
Abstract
The utilization of bacterial metalloenzymes, especially ones not having mammalian (human) counterparts, has drawn attention to develop novel antibacterial agents to overcome drug resistance and especially multidrug resistance. In this review, we focus on the recent achievements on the development of inhibitors of bacterial enzymes peptide deformylase (PDF), metallo-β-lactamase (MBL), methionine aminopeptidase (MetAP) and UDP-3-O-acyl- N-acetylglucosamine deacetylase (LpxC). The state of the art of the design and investigation of inhibitors of bacterial metalloenzymes is presented, and challenges are outlined and discussed.
Collapse
Affiliation(s)
- Raivis Žalubovskis
- Latvian Institute of Organic Synthesis, Riga, Latvia.,Institute of Technology of Organic Chemistry, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Latvia
| | - Jean-Yves Winum
- Institut des Biomolecules Max Mousseron, Universite de Montpellier, France
| |
Collapse
|
33
|
Ding S, Dai RY, Wang WK, Cao Q, Lan LF, Zhou XL, Yang YS. Design, synthesis and structure-activity relationship evaluation of novel LpxC inhibitors as Gram-negative antibacterial agents. Bioorg Med Chem Lett 2018; 28:94-102. [DOI: 10.1016/j.bmcl.2017.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/28/2017] [Accepted: 12/04/2017] [Indexed: 10/18/2022]
|
34
|
Powers MJ, Trent MS. Expanding the paradigm for the outer membrane: Acinetobacter baumannii in the absence of endotoxin. Mol Microbiol 2017; 107:47-56. [PMID: 29114953 DOI: 10.1111/mmi.13872] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2017] [Indexed: 12/30/2022]
Abstract
Asymmetry in the outer membrane has long defined the cell envelope of Gram-negative bacteria. This asymmetry, with lipopolysaccharide (LPS) or lipooligosaccharide (LOS) exclusively in the outer leaflet of the membrane, establishes an impermeable barrier that protects the cell from a number of stressors in the environment. Work done over the past 5 years has shown that Acinetobacter baumannii has the remarkable capability to survive with inactivated production of lipid A biosynthesis and the absence of LOS in its outer membrane. The implications of LOS-deficient A. baumannii are far-reaching - from impacts on cell envelope biogenesis and maintenance, bacterial physiology, antibiotic resistance and virulence. This review examines recent work that has contributed to our understanding of LOS-deficiency and compares it to studies done on Neisseria meningitidis and Moraxella catarrhalis; the two other organisms with this capability.
Collapse
Affiliation(s)
- Matthew Joseph Powers
- Department of Infectious Diseases, University of Georgia, 510 DW Brooks Drive, Athens, GA 30602, USA.,Department of Microbiology, University of Georgia, Athens, GA, USA
| | - M Stephen Trent
- Department of Infectious Diseases, University of Georgia, 510 DW Brooks Drive, Athens, GA 30602, USA
| |
Collapse
|
35
|
Affiliation(s)
- Dmitrii V. Kalinin
- Institut für Organische Chemie, Universität Hamburg, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Münster, Germany
- Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University of Münster, Münster, Germany
| | - Ralph Holl
- Institut für Organische Chemie, Universität Hamburg, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems
| |
Collapse
|
36
|
LpxK Is Essential for Growth of Acinetobacter baumannii ATCC 19606: Relationship to Toxic Accumulation of Lipid A Pathway Intermediates. mSphere 2017; 2:mSphere00199-17. [PMID: 28815210 PMCID: PMC5555675 DOI: 10.1128/msphere.00199-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/06/2017] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative pathogen for which new therapies are needed. The lipid A biosynthetic pathway has several potential enzyme targets for the development of anti-Gram-negative agents (e.g., LpxC). However, A. baumannii ATCC 19606 can grow in the absence of LpxC and, correspondingly, of lipid A. In contrast, we show that cellular depletion of LpxK, a kinase occurring later in the pathway, inhibits growth. Growth inhibition results from toxic accumulation of lipid A pathway intermediates, since chemical inhibition of LpxC or fatty acid biosynthesis rescues cell growth upon loss of LpxK. Overall, this suggests that targets such as LpxK can be essential for growth even in those Gram-negative bacteria that do not require lipid A biosynthesis per se. This strain provides an elegant tool to derive a better understanding of the steps in a pathway that is the focus of intense interest for the development of novel antibacterials. Acinetobacter baumannii ATCC 19606 can grow without lipid A, the major component of lipooligosaccharide. However, we previously reported that depletion of LpxH (the fourth enzyme in the lipid A biosynthetic pathway) prevented growth of this strain due to toxic accumulation of lipid A pathway intermediates. Here, we explored whether a similar phenomenon occurred with depletion of LpxK, a kinase that phosphorylates disaccharide 1-monophosphate (DSMP) at the 4′ position to yield lipid IVA. An A. baumannii ATCC 19606 derivative with LpxK expression under the control of an isopropyl β-d-1-thiogalactopyranoside (IPTG)-regulated expression system failed to grow without induction, indicating that LpxK is essential for growth. Light and electron microscopy of LpxK-depleted cells revealed morphological changes relating to the cell envelope, consistent with toxic accumulation of lipid A pathway intermediates disrupting cell membranes. Using liquid chromatography-mass spectrometry (LCMS), cellular accumulation of the detergent-like pathway intermediates DSMP and lipid X was shown. Toxic accumulation was further supported by restoration of growth upon chemical inhibition of LpxC (upstream of LpxK and the first committed step of lipid A biosynthesis) using CHIR-090. Inhibitors of fatty acid synthesis also abrogated the requirement for LpxK expression. Growth rescue with these inhibitors was possible on Mueller-Hinton agar but not on MacConkey agar. The latter contains outer membrane-impermeable bile salts, suggesting that despite growth restoration, the cell membrane permeability barrier was not restored. Therefore, LpxK is essential for growth of A. baumannii, since loss of LpxK causes accumulation of detergent-like pathway intermediates that inhibit cell growth. IMPORTANCEAcinetobacter baumannii is a Gram-negative pathogen for which new therapies are needed. The lipid A biosynthetic pathway has several potential enzyme targets for the development of anti-Gram-negative agents (e.g., LpxC). However, A. baumannii ATCC 19606 can grow in the absence of LpxC and, correspondingly, of lipid A. In contrast, we show that cellular depletion of LpxK, a kinase occurring later in the pathway, inhibits growth. Growth inhibition results from toxic accumulation of lipid A pathway intermediates, since chemical inhibition of LpxC or fatty acid biosynthesis rescues cell growth upon loss of LpxK. Overall, this suggests that targets such as LpxK can be essential for growth even in those Gram-negative bacteria that do not require lipid A biosynthesis per se. This strain provides an elegant tool to derive a better understanding of the steps in a pathway that is the focus of intense interest for the development of novel antibacterials.
Collapse
|
37
|
Piizzi G, Parker DT, Peng Y, Dobler M, Patnaik A, Wattanasin S, Liu E, Lenoir F, Nunez J, Kerrigan J, McKenney D, Osborne C, Yu D, Lanieri L, Bojkovic J, Dzink-Fox J, Lilly MD, Sprague ER, Lu Y, Wang H, Ranjitkar S, Xie L, Wang B, Glick M, Hamann LG, Tommasi R, Yang X, Dean CR. Design, Synthesis, and Properties of a Potent Inhibitor of Pseudomonas aeruginosa Deacetylase LpxC. J Med Chem 2017; 60:5002-5014. [PMID: 28549219 DOI: 10.1021/acs.jmedchem.7b00377] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Over the past several decades, the frequency of antibacterial resistance in hospitals, including multidrug resistance (MDR) and its association with serious infectious diseases, has increased at alarming rates. Pseudomonas aeruginosa is a leading cause of nosocomial infections, and resistance to virtually all approved antibacterial agents is emerging in this pathogen. To address the need for new agents to treat MDR P. aeruginosa, we focused on inhibiting the first committed step in the biosynthesis of lipid A, the deacetylation of uridyldiphospho-3-O-(R-hydroxydecanoyl)-N-acetylglucosamine by the enzyme LpxC. We approached this through the design, synthesis, and biological evaluation of novel hydroxamic acid LpxC inhibitors, exemplified by 1, where cytotoxicity against mammalian cell lines was reduced, solubility and plasma-protein binding were improved while retaining potent anti-pseudomonal activity in vitro and in vivo.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - David McKenney
- Infectious Diseases Area, Novartis Institutes for BioMedical Research , Emeryville, California 94608, United States
| | - Colin Osborne
- Infectious Diseases Area, Novartis Institutes for BioMedical Research , Emeryville, California 94608, United States
| | - Donghui Yu
- Infectious Diseases Area, Novartis Institutes for BioMedical Research , Emeryville, California 94608, United States
| | - Leanne Lanieri
- Infectious Diseases Area, Novartis Institutes for BioMedical Research , Emeryville, California 94608, United States
| | - Jade Bojkovic
- Infectious Diseases Area, Novartis Institutes for BioMedical Research , Emeryville, California 94608, United States
| | - JoAnn Dzink-Fox
- Infectious Diseases Area, Novartis Institutes for BioMedical Research , Emeryville, California 94608, United States
| | - Maria-Dawn Lilly
- Infectious Diseases Area, Novartis Institutes for BioMedical Research , Emeryville, California 94608, United States
| | | | | | | | - Srijan Ranjitkar
- Infectious Diseases Area, Novartis Institutes for BioMedical Research , Emeryville, California 94608, United States
| | - Lili Xie
- Infectious Diseases Area, Novartis Institutes for BioMedical Research , Emeryville, California 94608, United States
| | | | | | | | | | - Xia Yang
- Infectious Diseases Area, Novartis Institutes for BioMedical Research , Emeryville, California 94608, United States
| | - Charles R Dean
- Infectious Diseases Area, Novartis Institutes for BioMedical Research , Emeryville, California 94608, United States
| |
Collapse
|
38
|
Richie DL, Takeoka KT, Bojkovic J, Metzger LE, Rath CM, Sawyer WS, Wei JR, Dean CR. Toxic Accumulation of LPS Pathway Intermediates Underlies the Requirement of LpxH for Growth of Acinetobacter baumannii ATCC 19606. PLoS One 2016; 11:e0160918. [PMID: 27526195 PMCID: PMC4985137 DOI: 10.1371/journal.pone.0160918] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 07/27/2016] [Indexed: 12/05/2022] Open
Abstract
The lipid A moiety of lipopolysaccharide (LPS) is the main constituent of the outer leaflet of the Gram-negative bacterial outer membrane (OM) and is essential in many Gram-negative pathogens. An exception is Acinetobacter baumannii ATCC 19606, where mutants lacking enzymes occurring early in lipid A biosynthesis (LpxA, LpxC or LpxD), and correspondingly lacking LPS, can grow. In contrast, we show here that LpxH, an enzyme that occurs downstream of LpxD in the lipid A biosynthetic pathway, is essential for growth in this strain. Multiple attempts to disrupt lpxH on the genome were unsuccessful, and when LpxH expression was controlled by an isopropyl β-d-1-thiogalactopyranoside (IPTG) inducible promoter, cell growth under typical laboratory conditions required IPTG induction. Mass spectrometry analysis of cells shifted from LpxH-induced to uninduced (and whose growth was correspondingly slowing as LpxH was depleted) showed a large cellular accumulation of UDP-2,3-diacyl-GlcN (substrate of LpxH), a C14:0(3-OH) acyl variant of the LpxD substrate (UDP-3-O-[(R)-3-OH-C14]-GlcN), and disaccharide 1-monophosphate (DSMP). Furthermore, the viable cell counts of the LpxH depleted cultures dropped modestly, and electron microscopy revealed clear defects at the cell (inner) membrane, suggesting lipid A intermediate accumulation was toxic. Consistent with this, blocking the synthesis of these intermediates by inhibition of the upstream LpxC enzyme using CHIR-090 abrogated the requirement for IPTG induction of LpxH. Taken together, these data indicate that LpxH is essential for growth in A. baumannii ATCC19606, because, unlike earlier pathway steps like LpxA or LpxC, blockage of LpxH causes accumulation of detergent-like pathway intermediates that prevents cell growth.
Collapse
Affiliation(s)
- Daryl L. Richie
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
| | - Kenneth T. Takeoka
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
| | - Jade Bojkovic
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
| | - Louis E. Metzger
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
| | - Christopher M. Rath
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
| | - William S. Sawyer
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
| | - Jun-Rong Wei
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
| | - Charles R. Dean
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
- * E-mail:
| |
Collapse
|
39
|
Erwin AL. Antibacterial Drug Discovery Targeting the Lipopolysaccharide Biosynthetic Enzyme LpxC. Cold Spring Harb Perspect Med 2016; 6:cshperspect.a025304. [PMID: 27235477 DOI: 10.1101/cshperspect.a025304] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The enzyme LpxC (UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase) is broadly conserved across Gram-negative bacteria and is essential for synthesis of lipid A, the membrane anchor of the lipopolysaccharides (LPSs), which are a major component of the outer membrane in nearly all Gram-negative bacteria. LpxC has been the focus of target-directed antibiotic discovery projects in numerous pharmaceutical and academic groups for more than 20 years. Despite intense effort, no LpxC inhibitor has been approved for therapeutic use, and only one has yet reached human studies. This article will summarize the history of LpxC as a drug target and the parallel history of research on LpxC biology. Both academic and industrial researchers have used LpxC inhibitors as tool compounds, leading to increased understanding of the differing mechanisms for regulation of LPS synthesis in Escherichia coli and Pseudomonas aeruginosa.
Collapse
|
40
|
Henderson JC, Zimmerman SM, Crofts AA, Boll JM, Kuhns LG, Herrera CM, Trent MS. The Power of Asymmetry: Architecture and Assembly of the Gram-Negative Outer Membrane Lipid Bilayer. Annu Rev Microbiol 2016; 70:255-78. [PMID: 27359214 DOI: 10.1146/annurev-micro-102215-095308] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Determining the chemical composition of biological materials is paramount to the study of natural phenomena. Here, we describe the composition of model gram-negative outer membranes, focusing on the predominant assembly, an asymmetrical bilayer of lipid molecules. We also give an overview of lipid biosynthetic pathways and molecular mechanisms that organize this material into the outer membrane bilayer. An emphasis is placed on the potential of these pathways as targets for antibiotic development. We discuss deviations in composition, through bacterial cell surface remodeling, and alternative modalities to the asymmetric lipid bilayer. Outer membrane lipid alterations of current microbiological interest, such as lipid structures found in commensal bacteria, are emphasized. Additionally, outer membrane components could potentially be engineered to develop vaccine platforms. Observations related to composition and assembly of gram-negative outer membranes will continue to generate novel discoveries, broaden biotechnologies, and reveal profound mysteries to compel future research.
Collapse
Affiliation(s)
- Jeremy C Henderson
- Department of Molecular Biosciences, The University of Texas at Austin, Texas 78712
| | - Shawn M Zimmerman
- Department of Infectious Diseases, The University of Georgia, Athens, Georgia 30602;
| | - Alexander A Crofts
- Department of Molecular Biosciences, The University of Texas at Austin, Texas 78712
| | - Joseph M Boll
- Department of Molecular Biosciences, The University of Texas at Austin, Texas 78712
| | - Lisa G Kuhns
- Department of Infectious Diseases, The University of Georgia, Athens, Georgia 30602;
| | - Carmen M Herrera
- Department of Infectious Diseases, The University of Georgia, Athens, Georgia 30602;
| | - M Stephen Trent
- Department of Infectious Diseases, The University of Georgia, Athens, Georgia 30602;
| |
Collapse
|
41
|
Titecat M, Liang X, Lee CJ, Charlet A, Hocquet D, Lambert T, Pagès JM, Courcol R, Sebbane F, Toone EJ, Zhou P, Lemaitre N. High susceptibility of MDR and XDR Gram-negative pathogens to biphenyl-diacetylene-based difluoromethyl-allo-threonyl-hydroxamate LpxC inhibitors. J Antimicrob Chemother 2016; 71:2874-82. [PMID: 27330072 DOI: 10.1093/jac/dkw210] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 05/04/2016] [Indexed: 02/02/2023] Open
Abstract
OBJECTIVES Inhibitors of uridine diphosphate-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC, which catalyses the first, irreversible step in lipid A biosynthesis) are a promising new class of antibiotics against Gram-negative bacteria. The objectives of the present study were to: (i) compare the antibiotic activities of three LpxC inhibitors (LPC-058, LPC-011 and LPC-087) and the reference inhibitor CHIR-090 against Gram-negative bacilli (including MDR and XDR isolates); and (ii) investigate the effect of combining these inhibitors with conventional antibiotics. METHODS MICs were determined for 369 clinical isolates (234 Enterobacteriaceae and 135 non-fermentative Gram-negative bacilli). Time-kill assays with LPC-058 were performed on four MDR/XDR strains, including Escherichia coli producing CTX-M-15 ESBL and Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii producing KPC-2, VIM-1 and OXA-23 carbapenemases, respectively. RESULTS LPC-058 was the most potent antibiotic and displayed the broadest spectrum of antimicrobial activity, with MIC90 values for Enterobacteriaceae, P. aeruginosa, Burkholderia cepacia and A. baumannii of 0.12, 0.5, 1 and 1 mg/L, respectively. LPC-058 was bactericidal at 1× or 2× MIC against CTX-M-15, KPC-2 and VIM-1 carbapenemase-producing strains and bacteriostatic at ≤4× MIC against OXA-23 carbapenemase-producing A. baumannii. Combinations of LPC-058 with β-lactams, amikacin and ciprofloxacin were synergistic against these strains, albeit in a species-dependent manner. LPC-058's high efficacy was attributed to the presence of the difluoromethyl-allo-threonyl head group and a linear biphenyl-diacetylene tail group. CONCLUSIONS These in vitro data highlight the therapeutic potential of the new LpxC inhibitor LPC-058 against MDR/XDR strains and set the stage for subsequent in vivo studies.
Collapse
Affiliation(s)
- Marie Titecat
- Univ. Lille, CNRS, INSERM, CHU Lille, U1019-UMR 8204, Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Xiaofei Liang
- Department of Chemistry, Duke University, Durham, NC 27708, USA
| | - Chul-Jin Lee
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Audrey Charlet
- Univ. Lille, CNRS, INSERM, CHU Lille, U1019-UMR 8204, Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Didier Hocquet
- UMR CNRS 6249, Chrono-environnement, Université de Bourgogne-Franche-Comté, Centre de Ressources Biologiques Ferdinand Cabanne, Hygiène Hospitalière, CHU Besançon, F-25000 Besançon, France
| | - Thierry Lambert
- EA 4043 Unité Bactéries Pathogènes et Santé (UBaPS), Univ. Paris-Sud, Unité Paris Saclay, F-92290 Châtenay-Malabry, France
| | - Jean-Marie Pagès
- UMR-MD1, Aix Marseille Université, Institut de Recherche Biomédicale des Armées, F-13000 Marseille, France
| | - René Courcol
- Univ. Lille, CNRS, INSERM, CHU Lille, U1019-UMR 8204, Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Florent Sebbane
- Univ. Lille, CNRS, INSERM, CHU Lille, U1019-UMR 8204, Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Eric J Toone
- Department of Chemistry, Duke University, Durham, NC 27708, USA Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Pei Zhou
- Department of Chemistry, Duke University, Durham, NC 27708, USA Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Nadine Lemaitre
- Univ. Lille, CNRS, INSERM, CHU Lille, U1019-UMR 8204, Center for Infection and Immunity of Lille, F-59000 Lille, France
| |
Collapse
|
42
|
Wagner S, Sommer R, Hinsberger S, Lu C, Hartmann RW, Empting M, Titz A. Novel Strategies for the Treatment of Pseudomonas aeruginosa Infections. J Med Chem 2016; 59:5929-69. [DOI: 10.1021/acs.jmedchem.5b01698] [Citation(s) in RCA: 176] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Stefanie Wagner
- Chemical
Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
| | - Roman Sommer
- Chemical
Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
| | - Stefan Hinsberger
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
- Drug
Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
| | - Cenbin Lu
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
- Drug
Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
| | - Rolf W. Hartmann
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
- Drug
Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
| | - Martin Empting
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
- Drug
Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
| | - Alexander Titz
- Chemical
Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany
- Deutsches Zentrum für Infektionsforschung (DZIF), 30625 Standort Hannover-Braunschweig, Germany
| |
Collapse
|
43
|
Characterization of an Acinetobacter baumannii lptD Deletion Strain: Permeability Defects and Response to Inhibition of Lipopolysaccharide and Fatty Acid Biosynthesis. J Bacteriol 2015; 198:731-41. [PMID: 26668262 DOI: 10.1128/jb.00639-15] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 12/04/2015] [Indexed: 01/03/2023] Open
Abstract
UNLABELLED 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 liquid chromatography-mass spectrometry (LCMS) analysis of LPS intermediates from UDP-3-O-R-3-hydroxylauroyl-N-acetyl-α-d-glucosamine through lipid IV(A) showed that the loss of LptD caused an accumulation of lipid IV(A). This suggested that pathway intermediate accumulation or mislocalization caused by the blockage of later LPS pathway steps impacts envelope integrity. Supporting this notion, chemical inhibition of lipid A precursor enzymes, including LpxC and FabB/F, in the lptD deletion strain partially rescued growth and permeability defects. IMPORTANCE New antibiotics to treat Gram-negative bacterial infections are urgently needed. Inhibition of LPS biosynthesis is attractive because this would impact viability and cell permeability. Therefore, a better understanding of this pathway is important, especially in strains such as A. baumannii ATCC 19606, where LPS biosynthesis is not essential in vitro. We show that ATCC 19606 also survives the loss of the final translocation of LPS into the OM (lptD deletion). Intriguingly, this impaired cell envelope integrity more than the loss of LPS biosynthesis (lpxC deletion), presumably due to the accumulation of toxic intermediates. Supporting this, chemical inhibition of LPS biosynthesis partially reversed this permeability defect. This extends our understanding of the LPS machinery and provides insights into potential interrelationships of the target steps along this important pathway.
Collapse
|
44
|
References. Antibiotics (Basel) 2015. [DOI: 10.1128/9781555819316.refs] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
45
|
Yao J, Bruhn DF, Frank MW, Lee RE, Rock CO. Activation of Exogenous Fatty Acids to Acyl-Acyl Carrier Protein Cannot Bypass FabI Inhibition in Neisseria. J Biol Chem 2015; 291:171-81. [PMID: 26567338 DOI: 10.1074/jbc.m115.699462] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Indexed: 11/06/2022] Open
Abstract
Neisseria is a Gram-negative pathogen with phospholipids composed of straight chain saturated and monounsaturated fatty acids, the ability to incorporate exogenous fatty acids, and lipopolysaccharides that are not essential. The FabI inhibitor, AFN-1252, was deployed as a chemical biology tool to determine whether Neisseria can bypass the inhibition of fatty acid synthesis by incorporating exogenous fatty acids. Neisseria encodes a functional FabI that was potently inhibited by AFN-1252. AFN-1252 caused a dose-dependent inhibition of fatty acid synthesis in growing Neisseria, a delayed inhibition of growth phenotype, and minimal inhibition of DNA, RNA, and protein synthesis, showing that its mode of action is through inhibiting fatty acid synthesis. Isotopic fatty acid labeling experiments showed that Neisseria encodes the ability to incorporate exogenous fatty acids into its phospholipids by an acyl-acyl carrier protein-dependent pathway. However, AFN-1252 remained an effective antibacterial when Neisseria were supplemented with exogenous fatty acids. These results demonstrate that extracellular fatty acids are activated by an acyl-acyl carrier protein synthetase (AasN) and validate type II fatty acid synthesis (FabI) as a therapeutic target against Neisseria.
Collapse
Affiliation(s)
| | - David F Bruhn
- Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | | | - Richard E Lee
- Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | | |
Collapse
|
46
|
Design, synthesis and biological evaluation of LpxC inhibitors with novel hydrophilic terminus. CHINESE CHEM LETT 2015. [DOI: 10.1016/j.cclet.2015.03.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
47
|
Emiola A, George J, Andrews SS. A Complete Pathway Model for Lipid A Biosynthesis in Escherichia coli. PLoS One 2015; 10:e0121216. [PMID: 25919634 PMCID: PMC4412817 DOI: 10.1371/journal.pone.0121216] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 02/12/2015] [Indexed: 11/19/2022] Open
Abstract
Lipid A is a highly conserved component of lipopolysaccharide (LPS), itself a major component of the outer membrane of Gram-negative bacteria. Lipid A is essential to cells and elicits a strong immune response from humans and other animals. We developed a quantitative model of the nine enzyme-catalyzed steps of Escherichia coli lipid A biosynthesis, drawing parameters from the experimental literature. This model accounts for biosynthesis regulation, which occurs through regulated degradation of the LpxC and WaaA (also called KdtA) enzymes. The LpxC degradation signal appears to arise from the lipid A disaccharide concentration, which we deduced from prior results, model results, and new LpxK overexpression results. The model agrees reasonably well with many experimental findings, including the lipid A production rate, the behaviors of mutants with defective LpxA enzymes, correlations between LpxC half-lives and cell generation times, and the effects of LpxK overexpression on LpxC concentrations. Its predictions also differ from some experimental results, which suggest modifications to the current understanding of the lipid A pathway, such as the possibility that LpxD can replace LpxA and that there may be metabolic channeling between LpxH and LpxB. The model shows that WaaA regulation may serve to regulate the lipid A production rate when the 3-deoxy-D-manno-oct-2-ulosonic acid (KDO) concentration is low and/or to control the number of KDO residues that get attached to lipid A. Computation of flux control coefficients showed that LpxC is the rate-limiting enzyme if pathway regulation is ignored, but that LpxK is the rate-limiting enzyme if pathway regulation is present, as it is in real cells. Control also shifts to other enzymes if the pathway substrate concentrations are not in excess. Based on these results, we suggest that LpxK may be a much better drug target than LpxC, which has been pursued most often.
Collapse
Affiliation(s)
- Akintunde Emiola
- School of Health, Sports and Bioscience, University of East London, London, United Kingdom
- * E-mail:
| | - John George
- School of Health, Sports and Bioscience, University of East London, London, United Kingdom
| | - Steven S. Andrews
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| |
Collapse
|
48
|
Jana SK, Löppenberg M, Daniliuc CG, Holl R. Synthesis and biological evaluation of C-ethynyl furanosides as LpxC inhibitors. Tetrahedron 2015. [DOI: 10.1016/j.tet.2014.12.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
49
|
Murphy-Benenato KE, Olivier N, Choy A, Ross PL, Miller MD, Thresher J, Gao N, Hale MR. Synthesis, Structure, and SAR of Tetrahydropyran-Based LpxC Inhibitors. ACS Med Chem Lett 2014; 5:1213-8. [PMID: 25408833 DOI: 10.1021/ml500210x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 09/23/2014] [Indexed: 01/25/2023] Open
Abstract
In the search for novel Gram-negative agents, we performed a comprehensive search of the AstraZeneca collection and identified a tetrahydropyran-based matrix metalloprotease (MMP) inhibitor that demonstrated nanomolar inhibition of UDP-3-O-(acyl)-N-acetylglucosamine deacetylase (LpxC). Crystallographic studies in Aquifex aeolicus LpxC indicated the tetrahydropyran engaged in the same hydrogen bonds and van der Waals interactions as other known inhibitors. Systematic optimization of three locales on the scaffold provided compounds with improved Gram-negative activity. However, the optimization of LpxC activity was not accompanied by reduced inhibition of MMPs. Comparison of the crystal structure of the native product, UDP-3-O-(acyl)-glucosamine, in Aquifex aeolicus to the structure of a tetrahydropyran-based inhibitor indicates pathways for future optimization.
Collapse
Affiliation(s)
- Kerry E. Murphy-Benenato
- Department of Chemistry, Infection Innovative Medicines, and ‡Discovery Sciences, AstraZeneca R&D, Boston, 35 Gatehouse Drive, Waltham, Massachusetts 02451, United States
| | | | - Allison Choy
- Department of Chemistry, Infection Innovative Medicines, and ‡Discovery Sciences, AstraZeneca R&D, Boston, 35 Gatehouse Drive, Waltham, Massachusetts 02451, United States
| | | | - Matthew D. Miller
- Department of Chemistry, Infection Innovative Medicines, and ‡Discovery Sciences, AstraZeneca R&D, Boston, 35 Gatehouse Drive, Waltham, Massachusetts 02451, United States
| | - Jason Thresher
- Department of Chemistry, Infection Innovative Medicines, and ‡Discovery Sciences, AstraZeneca R&D, Boston, 35 Gatehouse Drive, Waltham, Massachusetts 02451, United States
| | | | - Michael R. Hale
- Department of Chemistry, Infection Innovative Medicines, and ‡Discovery Sciences, AstraZeneca R&D, Boston, 35 Gatehouse Drive, Waltham, Massachusetts 02451, United States
| |
Collapse
|
50
|
LpxC inhibitors as new antibacterial agents and tools for studying regulation of lipid A biosynthesis in Gram-negative pathogens. mBio 2014; 5:e01551-14. [PMID: 25271285 PMCID: PMC4196226 DOI: 10.1128/mbio.01551-14] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The problem of multidrug resistance in serious Gram-negative bacterial pathogens has escalated so severely that new cellular targets and pathways need to be exploited to avoid many of the preexisting antibiotic resistance mechanisms that are rapidly disseminating to new strains. The discovery of small-molecule inhibitors of LpxC, the enzyme responsible for the first committed step in the biosynthesis of lipid A, represents a clinically unprecedented strategy to specifically act against Gram-negative organisms such as Pseudomonas aeruginosa and members of the Enterobacteriaceae. In this report, we describe the microbiological characterization of LpxC-4, a recently disclosed inhibitor of this bacterial target, and demonstrate that its spectrum of activity extends to several of the pathogenic species that are most threatening to human health today. We also show that spontaneous generation of LpxC-4 resistance occurs at frequencies comparable to those seen with marketed antibiotics, and we provide an in-depth analysis of the mechanisms of resistance utilized by target pathogens. Interestingly, these isolates also served as tools to further our understanding of the regulation of lipid A biosynthesis and enabled the discovery that this process occurs very distinctly between P. aeruginosa and members of the Enterobacteriaceae. Finally, we demonstrate that LpxC-4 is efficacious in vivo against multiple strains in different models of bacterial infection and that the major first-step resistance mechanisms employed by the intended target organisms can still be effectively treated with this new inhibitor. New antibiotics are needed for the effective treatment of serious infections caused by Gram-negative pathogens, and the responsibility of identifying new drug candidates rests squarely on the shoulders of the infectious disease community. The limited number of validated cellular targets and approaches, along with the increasing amount of antibiotic resistance that is spreading throughout the clinical environment, has prompted us to explore the utility of inhibitors of novel targets and pathways in these resistant organisms, since preexisting target-based resistance should be negligible. Lipid A biosynthesis is an essential process for the formation of lipopolysaccharide, which is a critical component of the Gram-negative outer membrane. In this report, we describe the in vitro and in vivo characterization of novel inhibitors of LpxC, an enzyme whose activity is required for proper lipid A biosynthesis, and demonstrate that our lead compound has the requisite attributes to warrant further consideration as a novel antibiotic.
Collapse
|