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Podlesainski D, Adeniyi ET, Gröner Y, Schulz F, Krisilia V, Rehberg N, Richter T, Sehr D, Xie H, Simons VE, Kiffe-Delf AL, Kaschani F, Ioerger TR, Kaiser M, Kalscheuer R. The anti-tubercular callyaerins target the Mycobacterium tuberculosis-specific non-essential membrane protein Rv2113. Cell Chem Biol 2024:S2451-9456(24)00221-6. [PMID: 38981479 DOI: 10.1016/j.chembiol.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 04/19/2024] [Accepted: 06/11/2024] [Indexed: 07/11/2024]
Abstract
Spread of antimicrobial resistances urges a need for new drugs against Mycobacterium tuberculosis (Mtb) with mechanisms differing from current antibiotics. Previously, callyaerins were identified as promising anti-tubercular agents, representing a class of hydrophobic cyclopeptides with an unusual (Z)-2,3-di-aminoacrylamide unit. Here, we investigated the molecular mechanisms underlying their antimycobacterial properties. Structure-activity relationship studies enabled the identification of structural determinants relevant for antibacterial activity. Callyaerins are bacteriostatics selectively active against Mtb, including extensively drug-resistant strains, with minimal cytotoxicity against human cells and promising intracellular activity. By combining mutant screens and various chemical proteomics approaches, we showed that callyaerins target the non-essential, Mtb-specific membrane protein Rv2113, triggering a complex dysregulation of the proteome, characterized by global downregulation of lipid biosynthesis, cell division, DNA repair, and replication. Our study thus identifies Rv2113 as a previously undescribed Mtb-specific drug target and demonstrates that also non-essential proteins may represent efficacious targets for antimycobacterial drugs.
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Affiliation(s)
- David Podlesainski
- Center of Medical Biotechnology (ZMB), Faculty of Biology, Chemical Biology, University of Duisburg-Essen, 45141 Essen, Germany
| | - Emmanuel T Adeniyi
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute of Pharmaceutical Biology and Biotechnology, 40225 Düsseldorf, Germany
| | - Yvonne Gröner
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute of Pharmaceutical Biology and Biotechnology, 40225 Düsseldorf, Germany
| | - Florian Schulz
- Center of Medical Biotechnology (ZMB), Faculty of Biology, Chemical Biology, University of Duisburg-Essen, 45141 Essen, Germany
| | - Violetta Krisilia
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute of Pharmaceutical Biology and Biotechnology, 40225 Düsseldorf, Germany
| | - Nidja Rehberg
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute of Pharmaceutical Biology and Biotechnology, 40225 Düsseldorf, Germany
| | - Tim Richter
- Center of Medical Biotechnology (ZMB), Faculty of Biology, Chemical Biology, University of Duisburg-Essen, 45141 Essen, Germany
| | - Daria Sehr
- Center of Medical Biotechnology (ZMB), Faculty of Biology, Chemical Biology, University of Duisburg-Essen, 45141 Essen, Germany
| | - Huzhuyue Xie
- Center of Medical Biotechnology (ZMB), Faculty of Biology, Chemical Biology, University of Duisburg-Essen, 45141 Essen, Germany
| | - Viktor E Simons
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute of Pharmaceutical Biology and Biotechnology, 40225 Düsseldorf, Germany
| | - Anna-Lene Kiffe-Delf
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute of Pharmaceutical Biology and Biotechnology, 40225 Düsseldorf, Germany
| | - Farnusch Kaschani
- Center of Medical Biotechnology (ZMB), Faculty of Biology, Chemical Biology, University of Duisburg-Essen, 45141 Essen, Germany
| | - Thomas R Ioerger
- Department of Computer Science, Texas A&M University, College Station, TX 77843, USA
| | - Markus Kaiser
- Center of Medical Biotechnology (ZMB), Faculty of Biology, Chemical Biology, University of Duisburg-Essen, 45141 Essen, Germany.
| | - Rainer Kalscheuer
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute of Pharmaceutical Biology and Biotechnology, 40225 Düsseldorf, Germany.
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2
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Parkhill SL, Johnson EO. Integrating bacterial molecular genetics with chemical biology for renewed antibacterial drug discovery. Biochem J 2024; 481:839-864. [PMID: 38958473 DOI: 10.1042/bcj20220062] [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: 05/07/2024] [Revised: 06/20/2024] [Accepted: 06/24/2024] [Indexed: 07/04/2024]
Abstract
The application of dyes to understanding the aetiology of infection inspired antimicrobial chemotherapy and the first wave of antibacterial drugs. The second wave of antibacterial drug discovery was driven by rapid discovery of natural products, now making up 69% of current antibacterial drugs. But now with the most prevalent natural products already discovered, ∼107 new soil-dwelling bacterial species must be screened to discover one new class of natural product. Therefore, instead of a third wave of antibacterial drug discovery, there is now a discovery bottleneck. Unlike natural products which are curated by billions of years of microbial antagonism, the vast synthetic chemical space still requires artificial curation through the therapeutics science of antibacterial drugs - a systematic understanding of how small molecules interact with bacterial physiology, effect desired phenotypes, and benefit the host. Bacterial molecular genetics can elucidate pathogen biology relevant to therapeutics development, but it can also be applied directly to understanding mechanisms and liabilities of new chemical agents with new mechanisms of action. Therefore, the next phase of antibacterial drug discovery could be enabled by integrating chemical expertise with systematic dissection of bacterial infection biology. Facing the ambitious endeavour to find new molecules from nature or new-to-nature which cure bacterial infections, the capabilities furnished by modern chemical biology and molecular genetics can be applied to prospecting for chemical modulators of new targets which circumvent prevalent resistance mechanisms.
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Affiliation(s)
- Susannah L Parkhill
- Systems Chemical Biology of Infection and Resistance Laboratory, The Francis Crick Institute, London, U.K
- Faculty of Life Sciences, University College London, London, U.K
| | - Eachan O Johnson
- Systems Chemical Biology of Infection and Resistance Laboratory, The Francis Crick Institute, London, U.K
- Faculty of Life Sciences, University College London, London, U.K
- Department of Chemistry, Imperial College, London, U.K
- Department of Chemistry, King's College London, London, U.K
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3
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Harkness RW, Zhao H, Toyama Y, Schuck P, Kay LE. Exploring Host-Guest Interactions within a 600 kDa DegP Protease Cage Complex Using Hydrodynamics Measurements and Methyl-TROSY NMR. J Am Chem Soc 2024; 146:8242-8259. [PMID: 38477967 DOI: 10.1021/jacs.3c13247] [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: 03/14/2024]
Abstract
The DegP protease-chaperone operates within the periplasm of Gram-negative bacteria, where it assists in the regulation of protein homeostasis, promotes virulence, and is essential to survival under stress. To carry out these tasks, DegP forms a network of preorganized apo oligomers that facilitate the capture of substrates within distributions of cage-like complexes which expand to encapsulate clients of various sizes. Although the architectures of DegP cage complexes are well understood, little is known about the structures, dynamics, and interactions of client proteins within DegP cages and the relationship between client structural dynamics and function. Here, we probe host-guest interactions within a 600 kDa DegP cage complex throughout the DegP activation cycle using a model α-helical client protein through a combination of hydrodynamics measurements, methyl-transverse relaxation optimized spectroscopy-based solution nuclear magnetic resonance studies, and proteolytic activity assays. We find that in the presence of the client, DegP cages assemble cooperatively with few intermediates. Our data further show that the N-terminal half of the bound client, which projects into the interior of the cages, is predominantly unfolded and flexible, and exchanges between multiple conformational states over a wide range of time scales. Finally, we show that a concerted structural transition of the protease domains of DegP occurs upon client engagement, leading to activation. Together, our findings support a model of DegP as a highly cooperative and dynamic molecular machine that stabilizes unfolded states of clients, primarily via interactions with their C-termini, giving rise to efficient cleavage.
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Affiliation(s)
- Robert W Harkness
- Department of Biochemistry, University of Toronto, Toronto M5S 1A8, Canada
- Department of Molecular Genetics, University of Toronto, Toronto M5S 1A8, Canada
- Department of Chemistry, University of Toronto, Toronto M5S 3H6, Canada
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto M5G 0A4, Canada
| | - Huaying Zhao
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Yuki Toyama
- Department of Biochemistry, University of Toronto, Toronto M5S 1A8, Canada
- Department of Molecular Genetics, University of Toronto, Toronto M5S 1A8, Canada
- Department of Chemistry, University of Toronto, Toronto M5S 3H6, Canada
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto M5G 0A4, Canada
| | - Peter Schuck
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Lewis E Kay
- Department of Biochemistry, University of Toronto, Toronto M5S 1A8, Canada
- Department of Molecular Genetics, University of Toronto, Toronto M5S 1A8, Canada
- Department of Chemistry, University of Toronto, Toronto M5S 3H6, Canada
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto M5G 0A4, Canada
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4
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Yu J, Lu H, Zhu L. Mutation-driven resistance development in wastewater E. coli upon low-level cephalosporins: Pharmacophore contribution and novel mechanism. WATER RESEARCH 2024; 252:121235. [PMID: 38310801 DOI: 10.1016/j.watres.2024.121235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/24/2024] [Accepted: 01/28/2024] [Indexed: 02/06/2024]
Abstract
Cephalosporins have been widely applied in clinical and veterinary settings and detected at increasing concentrations in water environments. They potentially induce high-level antibiotic resistance at environmental concentrations. This study characterized how typical wastewater bacteria developed heritable antibiotic resistance under exposure to different cephalosporins, including pharmacophore-resistance correlation, resistance mechanism, and occurrence of resistance-relevant mutations in different water environments. Wastewater-isolated E. coli JX1 was exposed to eight cephalosporins individually at 25 µg/L for 60 days. Multidrug resistance developed and diverse mutations arose in selected mutants, where a single mutation in ATP phosphoribosyltransferase encoding gene (hisG) resulted in up to 128-fold increase in resistance to meropenem. Molprint2D pharma RQSAR analysis revealed that hydrogen-bond acceptors and hydrophobic groups in the R1 and R2 substituents of cephalosporins contributed positively to antibiotic resistance. Some of these pharmacophores may persist during bio- or photo-degradation in the environment. hisG mutation confers a novel resistance mechanism by inhibiting fatty acid degradation, and its variants were more abundant in water-related E. coli (especially in the effluent of wastewater treatment plants) compared with those in non-water environments. These results suggest that specific degradation of particular pharmacophores in cephalosporins could be useful for controlling resistance development, and mutations in previously unreported resistance genes (e.g., hisG) can lead to overlooked antibiotic resistance risks in water environments.
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Affiliation(s)
- Jinxian Yu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China
| | - Huijie Lu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Lizhong Zhu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China.
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5
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Noskova Y, Son O, Tekutyeva L, Balabanova L. Purification and Characterization of a DegP-Type Protease from the Marine Bacterium Cobetia amphilecti KMM 296. Microorganisms 2023; 11:1852. [PMID: 37513024 PMCID: PMC10383082 DOI: 10.3390/microorganisms11071852] [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: 06/13/2023] [Revised: 07/13/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023] Open
Abstract
A new member of the DegP-type periplasmic serine endoproteases of the S1C family from the marine bacterium Cobetia amphilecti KMM 296 (CamSP) was expressed in Escherichia coli cells. The calculated molecular weight, number of amino acids, and isoelectric point (pI) of the mature protein CamSP are 69.957 kDa, 666, and 4.84, respectively. The proteolytic activity of the purified recombinant protease CamSP was 2369.4 and 1550.9 U/mg with the use of 1% bovine serum albumin (BSA) and casein as the substrates, respectively. The enzyme CamSP exhibited maximum activity at pH 6.0-6.2, while it was stable over a wide pH range from 5.8 to 8.5. The optimal temperature for the CamSP protease activity was 50 °C. The enzyme required NaCl or KCl at concentrations of 0.3 and 0.5 M, respectively, for its maximum activity. The Michaelis constant (Km) and Vmax for BSA were determined to be 41.7 µg/mL and 0.036 µg/mL min-1, respectively. The metal ions Zn2+, Cu2+, Mn2+, Li2+, Mg2+, and Ca2+ slightly activated CamSP, while the addition of CoCl2 to the incubation mixture resulted in a twofold increase in its protease activity. Ethanol, isopropanol, glycerol, and Triton-X-100 increased the activity of CamSP from two- to four-times. The protease CamSP effectively degraded the wheat flour proteins but had no proteolytic activity towards soybean, corn, and the synthetic substrates, α-benzoyl-Arg-p-nitroanilide (BAPNA) and N-Succinyl-L-alanyl-L-alanyl-L-prolyl-L-phenylalanine 4-nitroanilide (SAPNA).
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Affiliation(s)
- Yulia Noskova
- Laboratory of Marine Biochemistry, G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Prospect 100-Letya Vladivostoka 152, 690022 Vladivostok, Russia
| | - Oksana Son
- Advanced Engineering School, Institute of Biotechnology, Bioengineering and Food Systems, Far Eastern Federal University, 10 Ajax Bay, Russky Island, 690922 Vladivostok, Russia
| | - Liudmila Tekutyeva
- Advanced Engineering School, Institute of Biotechnology, Bioengineering and Food Systems, Far Eastern Federal University, 10 Ajax Bay, Russky Island, 690922 Vladivostok, Russia
| | - Larissa Balabanova
- Laboratory of Marine Biochemistry, G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Prospect 100-Letya Vladivostoka 152, 690022 Vladivostok, Russia
- Advanced Engineering School, Institute of Biotechnology, Bioengineering and Food Systems, Far Eastern Federal University, 10 Ajax Bay, Russky Island, 690922 Vladivostok, Russia
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Tsai MJ, Lin CY, Trousil J, Sung CT, Lee MH, Fang JY, Yang SC. Proteinase K/Retinoic Acid-Loaded Cationic Liposomes as Multifunctional Anti-Acne Therapy to Disorganize Biofilm and Regulate Keratinocyte Proliferation. Int J Nanomedicine 2023; 18:3879-3896. [PMID: 37483315 PMCID: PMC10361279 DOI: 10.2147/ijn.s416966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 07/01/2023] [Indexed: 07/25/2023] Open
Abstract
Background Simultaneous anti-Cutibacterium acnes and anti-inflammatory actions are highly beneficial in treating acne vulgaris. In this study, we present novel anti-acne nanovesicles based on liposomes loaded with proteinase K (PK), retinoic acid (RA), and soyaethyl morpholinium ethosulfate (SME) to achieve an effective and safe treatment. Materials and Methods This study examined in vitro planktonic and biofilm C. acnes elimination, as well as the keratinocyte proliferation suppression by liposomes. The multifunctional liposomes for treating C. acnes in mice were also evaluated. Results We acquired multifunctional liposomes with a size of 71 nm and zeta potential of 31 mV. The antimicrobial activity of SME was enhanced after liposomal encapsulation according to the reduction of minimum bactericidal concentration (MBC) by 6-fold. The multifunctional liposomes exhibited a synergistically inhibitory effect on biofilm C. acnes colonization compared with the liposomes containing PK or those containing SME individually. The adhesive bacterial colony in the microplate was lessened by 62% after multifunctional liposome intervention. All liposomal formulations tested here demonstrated no cytotoxicity against the normal keratinocytes but inhibited C. acnes-stimulated cell hyperproliferation. The in vitro scratch assay indicated that the liposomal RA-but not free RA-restrained keratinocyte migration. The animal study showed that free RA combined with SME and multifunctional nanovesicles had a similar effect on diminishing C. acnes colonies in the skin. On the other hand, liposomes exhibited superior performance in recovering the impaired skin barrier function than the free control. We also found that RA-loaded nanovesicles had greater skin tolerability than free RA. Conclusion The cationic liposomes containing dual PK and RA represented a potential treatment to arrest bacterial infection and associated inflammation in acne.
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Affiliation(s)
- Ming-Jun Tsai
- School of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan
- Jhong Siao Urological Hospital, Kaohsiung, Taiwan
| | - Cheng-Yu Lin
- Pharmaceutics Laboratory, Graduate Institute of Natural Products, Chang Gung University, Kweishan, Taoyuan, Taiwan
| | - Jiří Trousil
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Calvin T Sung
- Department of Dermatology, University of California, Irvine, CA, USA
| | - Mei-Hua Lee
- Pharmaceutics Laboratory, Graduate Institute of Natural Products, Chang Gung University, Kweishan, Taoyuan, Taiwan
| | - Jia-You Fang
- Pharmaceutics Laboratory, Graduate Institute of Natural Products, Chang Gung University, Kweishan, Taoyuan, Taiwan
- Research Center for Food and Cosmetic Safety and Research Center for Chinese Herbal Medicine, Chang Gung University of Science and Technology, Kweishan, Taoyuan, Taiwan
- Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Shih-Chun Yang
- Department of Microbiology, Soochow University, Taipei, Taiwan
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7
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Widen SA, Bes IC, Koreshova A, Pliota P, Krogull D, Burga A. Virus-like transposons cross the species barrier and drive the evolution of genetic incompatibilities. Science 2023; 380:eade0705. [PMID: 37384706 DOI: 10.1126/science.ade0705] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 05/17/2023] [Indexed: 07/01/2023]
Abstract
Horizontal gene transfer, the movement of genetic material between species, has been reported across all major eukaryotic lineages. However, the underlying mechanisms of transfer and their impact on genome evolution are still poorly understood. While studying the evolutionary origin of a selfish element in the nematode Caenorhabditis briggsae, we discovered that Mavericks, ancient virus-like transposons related to giant viruses and virophages, are one of the long-sought vectors of horizontal gene transfer. We found that Mavericks gained a novel herpesvirus-like fusogen in nematodes, leading to the widespread exchange of cargo genes between extremely divergent species, bypassing sexual and genetic barriers spanning hundreds of millions of years. Our results show how the union between viruses and transposons causes horizontal gene transfer and ultimately genetic incompatibilities in natural populations.
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Affiliation(s)
- Sonya A Widen
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Israel Campo Bes
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Alevtina Koreshova
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), 1030 Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, A-1030 Vienna, Austria
| | - Pinelopi Pliota
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Daniel Krogull
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), 1030 Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, A-1030 Vienna, Austria
| | - Alejandro Burga
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), 1030 Vienna, Austria
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8
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Kadeřábková N, Mahmood AJS, Furniss RCD, Mavridou DAI. Making a chink in their armor: Current and next-generation antimicrobial strategies against the bacterial cell envelope. Adv Microb Physiol 2023; 83:221-307. [PMID: 37507160 PMCID: PMC10517717 DOI: 10.1016/bs.ampbs.2023.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
Gram-negative bacteria are uniquely equipped to defeat antibiotics. Their outermost layer, the cell envelope, is a natural permeability barrier that contains an array of resistance proteins capable of neutralizing most existing antimicrobials. As a result, its presence creates a major obstacle for the treatment of resistant infections and for the development of new antibiotics. Despite this seemingly impenetrable armor, in-depth understanding of the cell envelope, including structural, functional and systems biology insights, has promoted efforts to target it that can ultimately lead to the generation of new antibacterial therapies. In this article, we broadly overview the biology of the cell envelope and highlight attempts and successes in generating inhibitors that impair its function or biogenesis. We argue that the very structure that has hampered antibiotic discovery for decades has untapped potential for the design of novel next-generation therapeutics against bacterial pathogens.
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Affiliation(s)
- Nikol Kadeřábková
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States
| | - Ayesha J S Mahmood
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States
| | - R Christopher D Furniss
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Despoina A I Mavridou
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States; John Ring LaMontagne Center for Infectious Diseases, The University of Texas at Austin, Austin, TX, United States.
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9
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Frantz R, Gwozdzinski K, Gisch N, Doijad SP, Hudel M, Wille M, Abu Mraheil M, Schwudke D, Imirzalioglu C, Falgenhauer L, Ehrmann M, Chakraborty T. A Single Residue within the MCR-1 Protein Confers Anticipatory Resilience. Microbiol Spectr 2023; 11:e0359222. [PMID: 37071007 PMCID: PMC10269488 DOI: 10.1128/spectrum.03592-22] [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: 09/12/2022] [Accepted: 03/21/2023] [Indexed: 04/19/2023] Open
Abstract
The envelope stress response (ESR) of Gram-negative enteric bacteria senses fluctuations in nutrient availability and environmental changes to avert damage and promote survival. It has a protective role toward antimicrobials, but direct interactions between ESR components and antibiotic resistance genes have not been demonstrated. Here, we report interactions between a central regulator of ESR viz., the two-component signal transduction system CpxRA (conjugative pilus expression), and the recently described mobile colistin resistance protein (MCR-1). Purified MCR-1 is specifically cleaved within its highly conserved periplasmic bridge element, which links its N-terminal transmembrane domain with the C-terminal active-site periplasmic domain, by the CpxRA-regulated serine endoprotease DegP. Recombinant strains harboring cleavage site mutations in MCR-1 are either protease resistant or degradation susceptible, with widely differing consequences for colistin resistance. Transfer of the gene encoding a degradation-susceptible mutant to strains that lack either DegP or its regulator CpxRA restores expression and colistin resistance. MCR-1 production in Escherichia coli imposes growth restriction in strains lacking either DegP or CpxRA, effects that are reversed by transactive expression of DegP. Excipient allosteric activation of the DegP protease specifically inhibits growth of isolates carrying mcr-1 plasmids. As CpxRA directly senses acidification, growth of strains at moderately low pH dramatically increases both MCR-1-dependent phosphoethanolamine (PEA) modification of lipid A and colistin resistance levels. Strains expressing MCR-1 are also more resistant to antimicrobial peptides and bile acids. Thus, a single residue external to its active site induces ESR activity to confer resilience in MCR-1-expressing strains to commonly encountered environmental stimuli, such as changes in acidity and antimicrobial peptides. Targeted activation of the nonessential protease DegP can lead to the elimination of transferable colistin resistance in Gram-negative bacteria. IMPORTANCE The global presence of transferable mcr genes in a wide range of Gram-negative bacteria from clinical, veterinary, food, and aquaculture environments is disconcerting. Its success as a transmissible resistance factor remains enigmatic, because its expression imposes fitness costs and imparts only moderate levels of colistin resistance. Here, we show that MCR-1 triggers regulatory components of the envelope stress response, a system that senses fluctuations in nutrient availability and environmental changes, to promote bacterial survival in low pH environments. We identify a single residue within a highly conserved structural element of mcr-1 distal to its catalytic site that modulates resistance activity and triggers the ESR. Using mutational analysis, quantitative lipid A profiling and biochemical assays, we determined that growth in low pH environments dramatically increases colistin resistance levels and promotes resistance to bile acids and antimicrobial peptides. We exploited these findings to develop a targeted approach that eliminates mcr-1 and its plasmid carriers.
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Affiliation(s)
- Renate Frantz
- Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany
- German Center for Infection Research, Partner Site: Giessen-Marburg-Langen, Giessen, Germany
| | - Konrad Gwozdzinski
- Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany
- German Center for Infection Research, Partner Site: Giessen-Marburg-Langen, Giessen, Germany
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Swapnil Prakash Doijad
- Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany
- German Center for Infection Research, Partner Site: Giessen-Marburg-Langen, Giessen, Germany
| | - Martina Hudel
- Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany
| | - Maria Wille
- Institute of Hygiene and Environmental Medicine, Justus Liebig University Giessen, Giessen, Germany
| | - Mobarak Abu Mraheil
- Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany
| | - Dominik Schwudke
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
- German Center for Infection Research, Partner Site: Hamburg-Lübeck-Borstel-Riems, Borstel, Germany
- Airway Research Center North, Partner Site: Research Center Borstel, Borstel, Germany
| | - Can Imirzalioglu
- Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany
- Hessian University Competence Center for Hospital Hygiene, Justus Liebig University Giessen, Giessen, Germany
- German Center for Infection Research, Partner Site: Giessen-Marburg-Langen, Giessen, Germany
| | - Linda Falgenhauer
- Institute of Hygiene and Environmental Medicine, Justus Liebig University Giessen, Giessen, Germany
- Hessian University Competence Center for Hospital Hygiene, Justus Liebig University Giessen, Giessen, Germany
- German Center for Infection Research, Partner Site: Giessen-Marburg-Langen, Giessen, Germany
| | - Michael Ehrmann
- Center of Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Essen, Germany
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Trinad Chakraborty
- Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany
- Hessian University Competence Center for Hospital Hygiene, Justus Liebig University Giessen, Giessen, Germany
- German Center for Infection Research, Partner Site: Giessen-Marburg-Langen, Giessen, Germany
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10
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An X, Li N, Zhang S, Han Y, Zhang Q. Integration of proteome and metabolome profiling to reveal heat stress response and tolerance mechanisms of Serratia sp. AXJ-M for the bioremediation of papermaking black liquor. JOURNAL OF HAZARDOUS MATERIALS 2023; 450:131092. [PMID: 36857821 DOI: 10.1016/j.jhazmat.2023.131092] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 02/12/2023] [Accepted: 02/24/2023] [Indexed: 05/20/2023]
Abstract
The use of thermophilic bacteria for treating paper black liquor seems to be an efficient bioremediation strategy. In our previous work, the lignin-degrading bacterium Serratia sp. AXJ-M exhibited excellent heat tolerance ability. However, the molecular mechanism of its response to heat stress is unknown. Therefore, the heat stress response of AXJ-M was investigated using morphological and analytical methods. A comparative genomics analysis revealed interesting insights into the adaptability of the genetic basis of AXJ-M to harsh environments. Moreover, TMT quantitative proteomic analysis and parallel reaction monitoring (PRM) assays revealed that proteins related to both component systems, ABC transporters, carbohydrate, and amino metabolism, energy metabolism, etc., were differentially expressed. The non-targeted metabolome analysis revealed that the metabolic pathways associated with the fatty acid and amino acid biosynthesis and metabolism, together with the TCA cycle were most significantly enriched. Furthermore, integrated omics suggested that AXJ-M made metabolic adaptations to compensate for the increased energy demand caused by adverse environmental stimuli. The dominant heat regulator HspQ mediated heat adaptation of AXJ-M at high temperatures and modulated DyP expression. To summarize, the present study sheds light on the effect of high temperature on the lignin-degrading bacterium and its tolerance and underlying regulatory mechanisms.
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Affiliation(s)
- Xuejiao An
- College of Bioscience and Biotechnology, Jiangxi Agricultural University, Nanchang 330045, PR China.
| | - Ningjian Li
- College of Bioscience and Biotechnology, Jiangxi Agricultural University, Nanchang 330045, PR China
| | - Shulin Zhang
- College of Bioscience and Biotechnology, Jiangxi Agricultural University, Nanchang 330045, PR China
| | - Yanyan Han
- College of Bioscience and Biotechnology, Jiangxi Agricultural University, Nanchang 330045, PR China
| | - Qinghua Zhang
- College of Bioscience and Biotechnology, Jiangxi Agricultural University, Nanchang 330045, PR China
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11
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Wang Y, Zhang X, Lin Y, Lin H. The electron transport mechanism of downflow Leersia hexandra Swartz constructed wetland-microbial fuel cell when used to treat Cr(VI) and p-chlorophenol. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:37929-37945. [PMID: 36576625 DOI: 10.1007/s11356-022-24872-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 12/15/2022] [Indexed: 06/17/2023]
Abstract
Constructed wetland-microbial fuel cells are used to treat heavy metal and/or refractory organic wastewater. However, the electron transport mechanism of downflow Leersia hexandra constructed wetland-microbial fuel cells (DLCW-MFCs) is poorly understood when used to treat composite-polluted wastewater containing Cr(VI) and p-chlorophenol (4-CP) (C&P). In this study, metagenomics and in situ electrochemical techniques were used to investigate the electrochemical properties and the electricigens and their dominant gene functions. The DLCW-MFC was used to treat C&P and single-pollutant wastewater containing Cr(VI) (SC) and 4-CP (SP). The results showed that C&P had a higher current response and charge transfer capability and lower solution resistance plus charge transfer resistance. The anode bacteria solution of C&P contained more electron carriers (RF, FMN, FAD, CoQ10, and Cyt c). Metagenomic sequencing indicated that the total relative abundance of the microorganisms associated with electricity production (Desulfovibrio, Pseudomonas, Azospirillum, Nocardia, Microbacterium, Delftia, Geobacter, Acinetobacter, Bacillus, and Clostridium) was the highest in C&P (4.24%). However, Microbacterium was abundant in SP (0.12%), which exerted antagonistic effects on other electricigens. Among the 10 electricigens based on gene annotation, C&P had a higher overall relative abundance of the Unigene gene annotated to the KO pathway and CAZy level B compared with SC and SP, which were 1.31% and 0.582% respectively. Unigene153954 (ccmC), Unigene357497 (coxB), and Unigene1033667 (ubiG) were related to the electron carrier Cyt c, electron transfer, and CoQ biosynthesis, respectively. These were annotated to Desulfovibrio, Delftia, and Pseudomonas, respectively. Unigene161312 (AA1) used phenols and other substrates as electron donors and was annotated to Pseudomonas. Other functional carbohydrate enzyme genes (e.g., GT2, GT4, and GH31) used carbohydrates as donors and were annotated to other electricigens. This study provides a theoretical basis for electron transfer to promote the development of CW-MFCs.
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Affiliation(s)
- Yian Wang
- College of Environmental Science and Engineering, Guilin University of Technology, 319 Yanshan Street, Guilin, 541000, China
- Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Areas, Guilin University of Technology, 319 Yanshan Street, 541000, Guilin, China
| | - Xuehong Zhang
- College of Environmental Science and Engineering, Guilin University of Technology, 319 Yanshan Street, Guilin, 541000, China
- Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Areas, Guilin University of Technology, 319 Yanshan Street, 541000, Guilin, China
| | - Yi Lin
- College of Environmental Science and Engineering, Guilin University of Technology, 319 Yanshan Street, Guilin, 541000, China
- Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Areas, Guilin University of Technology, 319 Yanshan Street, 541000, Guilin, China
| | - Hua Lin
- College of Environmental Science and Engineering, Guilin University of Technology, 319 Yanshan Street, Guilin, 541000, China.
- Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Areas, Guilin University of Technology, 319 Yanshan Street, 541000, Guilin, China.
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12
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Cho THS, Pick K, Raivio TL. Bacterial envelope stress responses: Essential adaptors and attractive targets. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119387. [PMID: 36336206 DOI: 10.1016/j.bbamcr.2022.119387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 10/05/2022] [Accepted: 10/20/2022] [Indexed: 11/06/2022]
Abstract
Millions of deaths a year across the globe are linked to antimicrobial resistant infections. The need to develop new treatments and repurpose of existing antibiotics grows more pressing as the growing antimicrobial resistance pandemic advances. In this review article, we propose that envelope stress responses, the signaling pathways bacteria use to recognize and adapt to damage to the most vulnerable outer compartments of the microbial cell, are attractive targets. Envelope stress responses (ESRs) support colonization and infection by responding to a plethora of toxic envelope stresses encountered throughout the body; they have been co-opted into virulence networks where they work like global positioning systems to coordinate adhesion, invasion, microbial warfare, and biofilm formation. We highlight progress in the development of therapeutic strategies that target ESR signaling proteins and adaptive networks and posit that further characterization of the molecular mechanisms governing these essential niche adaptation machineries will be important for sparking new therapeutic approaches aimed at short-circuiting bacterial adaptation.
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Affiliation(s)
- Timothy H S Cho
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Kat Pick
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Tracy L Raivio
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
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13
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Ronzetti M, Baljinnyam B, Jalal I, Pal U, Simeonov A. Application of biophysical methods for improved protein production and characterization: A case study on an high-temperature requirement A-family bacterial protease. Protein Sci 2022; 31:e4498. [PMID: 36334045 PMCID: PMC9679970 DOI: 10.1002/pro.4498] [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: 06/24/2022] [Revised: 11/02/2022] [Accepted: 11/02/2022] [Indexed: 11/07/2022]
Abstract
The high-temperature requirement A (HtrA) serine protease family presents an attractive target class for antibacterial therapeutics development. These proteins possess dual protease and chaperone functions and contain numerous binding sites and regulatory loops, displaying diverse oligomerization patterns dependent on substrate type and occupancy. HtrA proteins that are natively purified coelute with contaminating peptides and activating species, shifting oligomerization and protein structure to differently activated populations. Here, a redesigned HtrA production results in cleaner preparations with high yields by overexpressing and purifying target protein from inclusion bodies under denaturing conditions, followed by a high-throughput screen for optimal refolding buffer composition using function-agnostic biophysical techniques that do not rely on target-specific measurements. We use Borrelia burgdorferi HtrA to demonstrate the effectiveness of our function-agnostic approach, while characterization with both new and established biophysical methods shows the retention of proteolytic and chaperone activity of the refolded protein. This systematic workflow and toolset will translate to the production of HtrA-family proteins in higher quantities of pure and monodisperse composition than the current literature standard, with applicability to a broad array of protein purification strategies.
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Affiliation(s)
- Michael Ronzetti
- National Center for Advancing Translational SciencesNational Institutes of HealthRockvilleMarylandUSA
- Department of Veterinary Medicine, College of Agriculture & Natural ResourcesUniversity of MarylandCollege ParkMarylandUSA
| | - Bolormaa Baljinnyam
- National Center for Advancing Translational SciencesNational Institutes of HealthRockvilleMarylandUSA
| | | | - Utpal Pal
- Department of Veterinary Medicine, College of Agriculture & Natural ResourcesUniversity of MarylandCollege ParkMarylandUSA
| | - Anton Simeonov
- National Center for Advancing Translational SciencesNational Institutes of HealthRockvilleMarylandUSA
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14
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Ronzetti MH, Baljinnyam B, Itkin Z, Jain S, Rai G, Zakharov AV, Pal U, Simeonov A. Application of temperature-responsive HIS-tag fluorophores to differential scanning fluorimetry screening of small molecule libraries. Front Pharmacol 2022; 13:1040039. [PMID: 36506591 PMCID: PMC9729254 DOI: 10.3389/fphar.2022.1040039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/04/2022] [Indexed: 11/25/2022] Open
Abstract
Differential scanning fluorimetry is a rapid and economical biophysical technique used to monitor perturbations to protein structure during a thermal gradient, most often by detecting protein unfolding events through an environment-sensitive fluorophore. By employing an NTA-complexed fluorophore that is sensitive to nearby structural changes in histidine-tagged protein, a robust and sensitive differential scanning fluorimetry (DSF) assay is established with the specificity of an affinity tag-based system. We developed, optimized, and miniaturized this HIS-tag DSF assay (HIS-DSF) into a 1536-well high-throughput biophysical platform using the Borrelial high temperature requirement A protease (BbHtrA) as a proof of concept for the workflow. A production run of the BbHtrA HIS-DSF assay showed a tight negative control group distribution of Tm values with an average coefficient of variation of 0.51% and median coefficient of variation of compound Tm of 0.26%. The HIS-DSF platform will provide an additional assay platform for future drug discovery campaigns with applications in buffer screening and optimization, target engagement screening, and other biophysical assay efforts.
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Affiliation(s)
- Michael H. Ronzetti
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, United States,Department of Veterinary Medicine, College of Agriculture and Natural Resources, University of Maryland, College Park, MD, United States
| | - Bolormaa Baljinnyam
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, United States,*Correspondence: Bolormaa Baljinnyam, ; Anton Simeonov,
| | - Zina Itkin
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, United States
| | - Sankalp Jain
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, United States
| | - Ganesha Rai
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, United States
| | - Alexey V. Zakharov
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, United States
| | - Utpal Pal
- Department of Veterinary Medicine, College of Agriculture and Natural Resources, University of Maryland, College Park, MD, United States
| | - Anton Simeonov
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, United States,*Correspondence: Bolormaa Baljinnyam, ; Anton Simeonov,
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15
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Kumar P, Shaikh AA, Kumar P, Gupta VK, Dhyani R, Sharma TK, Hussain A, Gangele K, Poluri KM, Rao KN, Malik RK, Pathania R, Navani NK. Double-Edged Nanobiotic Platform with Protean Functionality: Leveraging the Synergistic Antibacterial Activity of a Food-Grade Peptide to Mitigate Multidrug-Resistant Bacterial Pathogens. ACS APPLIED MATERIALS & INTERFACES 2022; 14:20652-20668. [PMID: 35486715 DOI: 10.1021/acsami.2c01385] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
While persistent efforts are being made to develop a novel arsenal against bacterial pathogens, the development of such materials remains a formidable challenge. One such strategy is to develop a multimodel antibacterial agent which will synergistically combat bacterial pathogens, including multidrug-resistant bacteria. Herein, we used pediocin, a class IIa bacteriocin, to decorate Ag° and developed a double-edged nanoplatform (Pd-SNPs) that inherits intrinsic properties of both antibacterial moieties, which engenders strikingly high antibacterial potency against a broad spectrum of bacterial pathogens including the ESKAPE category without displaying adverse cytotoxicity. The enhanced antimicrobial activity of Pd-SNPs is due to their higher affinity with the bacterial cell wall, which allows Pd-SNPs to penetrate the outer membrane, inducing membrane depolarization and the disruption of membrane integrity. Bioreporter assays revealed the upregulation of cpxP, degP, and sosX genes, triggering the burst of reactive oxygen species which eventually cause bacterial cell death. Pd-SNPs prevented biofilm formation, eradicated established biofilms, and inhibited persister cells. Pd-SNPs display unprecedented advantages because they are heat-resistant, retain antibacterial activity in human serum, and alleviate vancomycin intermediate Staphylococcus aureus (VISA) infection in the mouse model. In addition, Pd-SNPs wrapped in biodegradable nanofibers mitigated Listeria monocytogenes in cheese samples. Collectively, Pd-SNPs exhibited excellent biocompatibility and in vivo therapeutic potency without allowing foreseeable resistance acquisition by pathogens. These findings underscore new avenues for using a potent biocompatible nanobiotic platform to combat a wide range of bacterial pathogens.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Korasapati Nageswara Rao
- College of Dairy Technology, Sri Venkateswara Veterinary University, Tirupati, Andhra Pradesh 517502, India
| | - Ravinder Kumar Malik
- Department of Dairy Microbiology, National Dairy Research Institute, Karnal, Haryana 132001, India
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16
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Cho H, Lee H, Hong K, Chung H, Song I, Lee JS, Kim S. Bioinformatic Expansion of Borosins Uncovers Trans-Acting Peptide Backbone N-Methyltransferases in Bacteria. Biochemistry 2022; 61:183-194. [DOI: 10.1021/acs.biochem.1c00764] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Hyunjin Cho
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Hyunbin Lee
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Kyungtae Hong
- Bio-Med Program, KIST-School UST, Hwarang-ro 14 gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Hannah Chung
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Inseok Song
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Jun-Seok Lee
- Department of Pharmacology, Korea University College of Medicine, 73 Goryeodae-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Seokhee Kim
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
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17
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ElyC and Cyclic Enterobacterial Common Antigen Regulate Synthesis of Phosphoglyceride-Linked Enterobacterial Common Antigen. mBio 2021; 12:e0284621. [PMID: 34809459 PMCID: PMC8609368 DOI: 10.1128/mbio.02846-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Gram-negative cell envelope is a complex structure delineating the cell from its environment. Recently, we found that enterobacterial common antigen (ECA) plays a role maintaining the outer membrane (OM) permeability barrier, which excludes toxic molecules including many antibiotics. ECA is a conserved carbohydrate found throughout Enterobacterales (e.g., Salmonella, Klebsiella, and Yersinia). There are two OM forms of ECA (phosphoglyceride-linked ECAPG and lipopolysaccharide-linked ECALPS) and one periplasmic form of ECA (cyclic ECACYC). ECAPG, found in the outer leaflet of the OM, consists of a linear ECA oligomer attached to phosphoglyceride through a phosphodiester linkage. The process through which ECAPG is produced from polymerized ECA is unknown. Therefore, we set out to identify genes interacting genetically with ECAPG biosynthesis in Escherichia coli K-12 using the competition between ECA and peptidoglycan biosynthesis. Through transposon-directed insertion sequencing, we identified an interaction between elyC and ECAPG biosynthesis. ElyC is an inner membrane protein previously shown to alter peptidoglycan biosynthesis rates. We found ΔelyC was lethal specifically in strains producing ECAPG without other ECA forms, suggesting ECAPG biosynthesis impairment or dysregulation. Further characterization suggested ElyC inhibits ECAPG synthesis in a posttranscriptional manner. Moreover, the full impact of ElyC on ECA levels requires the presence of ECACYC. Our data demonstrate ECACYC can regulate ECAPG synthesis in strains wild type for elyC. Overall, our data demonstrate ElyC and ECACYC act in a novel pathway that regulates the production of ECAPG, supporting a model in which ElyC provides feedback regulation of ECAPG production based on the periplasmic levels of ECACYC.
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