1
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Luo Z, Li P, Zhang D, Zhu J, Wang W, Zhao W, Li P, Yuan G. A Novel Antimicrobial Mechanism of Azalomycin F Acting on Lipoteichoic Acid Synthase and Cell Envelope. Molecules 2024; 29:856. [PMID: 38398608 PMCID: PMC10893547 DOI: 10.3390/molecules29040856] [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: 12/16/2023] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
Lipoteichoic acid (LTA) plays an essential role in bacterial growth and resistance to antibiotics, and LTA synthetase (LtaS) was considered as an attractive target for combating Gram-positive infections. Azalomycin F, a natural guanidyl-containing polyhydroxy macrolide, can target the LTA of Staphylococcus aureus. Using various technologies including enzyme-linked immunosorbent assay, transmission electron microscope, proteomics, and parallel reaction monitoring, here, the experimental results indicated that azalomycin F can accelerate the LTA release and disrupt the cell envelope, which would also lead to the feedback upregulation on the expressions of LtaS and other related enzymes. Simultaneously, the reconstituted enzyme activity evaluations showed that azalomycin F can significantly inhibit the extracellular catalytic domain of LtaS (eLtaS), while this was vague for LtaS embedded in the liposomes. Subsequently, the fluorescence analyses for five incubation systems containing azalomycin F and eLtaS or the LtaS-embedded liposome indicated that azalomcyin F can spontaneously bind to the active center of LtaS. Combining the mass spectroscopy analyses and the molecular dockings, the results further indicated that this interaction involves the binding sites of substrates and the LTA prolongation, especially the residues Lys299, Phe353, Trp354 and His416. All these suggested that azalomycin F has multiple antibacterial mechanisms against S. aureus. It can not only inhibit LTA biosynthesis through the interactions of its guanidyl side chain with the active center of LtaS but also disrupt the cell envelope through the synergistic effect of accelerating the LTA release, damaging the cell membrane, and electrostatically interacting with LTA. Simultaneously, these antibacterial mechanisms exhibit a synergistic inhibition effect on S. aureus cells, which would eventually cause the cellular autolysis.
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Affiliation(s)
- Zilong Luo
- Biotechnological Engineering Center for Pharmaceutical Research and Development, Jiangxi Agricultural University, Nanchang 330045, China
| | - Pingyi Li
- Biotechnological Engineering Center for Pharmaceutical Research and Development, Jiangxi Agricultural University, Nanchang 330045, China
| | - Duoduo Zhang
- Biotechnological Engineering Center for Pharmaceutical Research and Development, Jiangxi Agricultural University, Nanchang 330045, China
| | - Jianping Zhu
- Laboratory of Natural Medicine and Microbiological Drug, College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China
| | - Wan Wang
- School of Basic Medicine, Nanchang Medical College, Nanchang 330006, China
| | - Wenjia Zhao
- Biotechnological Engineering Center for Pharmaceutical Research and Development, Jiangxi Agricultural University, Nanchang 330045, China
| | - Peibo Li
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Ganjun Yuan
- Biotechnological Engineering Center for Pharmaceutical Research and Development, Jiangxi Agricultural University, Nanchang 330045, China
- Laboratory of Natural Medicine and Microbiological Drug, College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China
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2
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Douglas EA, Marshall B, Alghamadi A, Joseph EA, Duggan S, Vittorio S, De Luca L, Serpi M, Laabei M. Improved Antibacterial Activity of 1,3,4-Oxadiazole-Based Compounds That Restrict Staphylococcus aureus Growth Independent of LtaS Function. ACS Infect Dis 2023; 9:2141-2159. [PMID: 37828912 PMCID: PMC10644342 DOI: 10.1021/acsinfecdis.3c00250] [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: 05/31/2023] [Indexed: 10/14/2023]
Abstract
The lipoteichoic acid (LTA) biosynthesis pathway has emerged as a promising antimicrobial therapeutic target. Previous studies identified the 1,3,4 oxadiazole compound 1771 as an LTA inhibitor with activity against Gram-positive pathogens. We have succeeded in making six 1771 derivatives and, through subsequent hit validation, identified the incorporation of a pentafluorosulfanyl substituent as central in enhancing activity. Our newly described derivative, compound 13, showed a 16- to 32-fold increase in activity compared to 1771 when tested against a cohort of multidrug-resistant Staphylococcus aureus strains while simultaneously exhibiting an improved toxicity profile against mammalian cells. Molecular techniques were employed in which the assumed target, lipoteichoic acid synthase (LtaS), was both deleted and overexpressed. Neither deletion nor overexpression of LtaS altered 1771 or compound 13 susceptibility; however, overexpression of LtaS increased the MIC of Congo red, a previously identified LtaS inhibitor. These data were further supported by comparing the docking poses of 1771 and derivatives in the LtaS active site, which indicated the possibility of an additional target(s). Finally, we show that both 1771 and compound 13 have activity that is independent of LtaS, extending to cover Gram-negative species if the outer membrane is first permeabilized, challenging the classification that these compounds are strict LtaS inhibitors.
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Affiliation(s)
| | - Brandon Marshall
- School
of Chemistry, Cardiff University, Cardiff CF10 3AT, Wales, U.K.
| | - Arwa Alghamadi
- School
of Chemistry, Cardiff University, Cardiff CF10 3AT, Wales, U.K.
| | - Erin A. Joseph
- School
of Chemistry, Cardiff University, Cardiff CF10 3AT, Wales, U.K.
| | - Seána Duggan
- Medical
Research Council Centre for Medical Mycology at the University of
Exeter, University of Exeter, Exeter EX4 4DQ, U.K.
| | - Serena Vittorio
- Department
of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina I-98125, Italy
| | - Laura De Luca
- Department
of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina I-98125, Italy
| | - Michaela Serpi
- School
of Chemistry, Cardiff University, Cardiff CF10 3AT, Wales, U.K.
| | - Maisem Laabei
- Department
of Life Sciences, University of Bath, Bath BA2 7AY, U.K.
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3
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Wu C, Lower BA, Moreira R, Dorantes D, Le T, Giurgiu C, Shi Y, van der Donk WA. Investigation into the mechanism of action of the antimicrobial peptide epilancin 15X. Front Microbiol 2023; 14:1247222. [PMID: 38029153 PMCID: PMC10652874 DOI: 10.3389/fmicb.2023.1247222] [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: 06/25/2023] [Accepted: 10/18/2023] [Indexed: 12/01/2023] Open
Abstract
Addressing the current antibiotic-resistance challenge would be aided by the identification of compounds with novel mechanisms of action. Epilancin 15X, a lantibiotic produced by Staphylococcus epidermidis 15 × 154, displays antimicrobial activity in the submicromolar range against a subset of pathogenic Gram-positive bacteria. S. epidermidis is a common member of the human skin or mucosal microbiota. We here investigated the mechanism of action of epilancin 15X. The compound is bactericidal against Staphylococcus carnosus as well as Bacillus subtilis and appears to kill these bacteria by membrane disruption. Structure-activity relationship studies using engineered analogs show that its conserved positively charged residues and dehydroamino acids are important for bioactivity, but the N-terminal lactyl group is tolerant of changes. Epilancin 15X treatment negatively affects fatty acid synthesis, RNA translation, and DNA replication and transcription without affecting cell wall biosynthesis. The compound appears localized to the surface of bacteria and is most potent in disrupting the membranes of liposomes composed of negatively charged membrane lipids in a lipid II independent manner. Epilancin 15X does not elicit a LiaRS response in B. subtilis but did upregulate VraRS in S. carnosus. Treatment of S. carnosus or B. subtilis with epilancin 15X resulted in an aggregation phenotype in microscopy experiments. Collectively these studies provide new information on epilancin 15X activity.
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Affiliation(s)
- Chunyu Wu
- Department of Biochemistry, University of Illinois at Urbana−Champaign, Champaign, IL, United States
| | - B. Alexis Lower
- Department of Chemistry, The Howard Hughes Medical Institute, University of Illinois at Urbana−Champaign, Champaign, IL, United States
| | - Ryan Moreira
- Department of Chemistry, The Howard Hughes Medical Institute, University of Illinois at Urbana−Champaign, Champaign, IL, United States
| | - Darian Dorantes
- Department of Biochemistry, University of Illinois at Urbana−Champaign, Champaign, IL, United States
| | - Tung Le
- Department of Chemistry, The Howard Hughes Medical Institute, University of Illinois at Urbana−Champaign, Champaign, IL, United States
| | - Constantin Giurgiu
- Department of Chemistry, The Howard Hughes Medical Institute, University of Illinois at Urbana−Champaign, Champaign, IL, United States
| | - Yanxiang Shi
- Department of Chemistry, The Howard Hughes Medical Institute, University of Illinois at Urbana−Champaign, Champaign, IL, United States
| | - Wilfred A. van der Donk
- Department of Biochemistry, University of Illinois at Urbana−Champaign, Champaign, IL, United States
- Department of Chemistry, The Howard Hughes Medical Institute, University of Illinois at Urbana−Champaign, Champaign, IL, United States
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4
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He B, Sachla AJ, Helmann JD. TerC proteins function during protein secretion to metalate exoenzymes. Nat Commun 2023; 14:6186. [PMID: 37794032 PMCID: PMC10550928 DOI: 10.1038/s41467-023-41896-1] [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: 05/08/2023] [Accepted: 09/14/2023] [Indexed: 10/06/2023] Open
Abstract
Cytosolic metalloenzymes acquire metals from buffered intracellular pools. How exported metalloenzymes are appropriately metalated is less clear. We provide evidence that TerC family proteins function in metalation of enzymes during export through the general secretion (Sec-dependent) pathway. Bacillus subtilis strains lacking MeeF(YceF) and MeeY(YkoY) have a reduced capacity for protein export and a greatly reduced level of manganese (Mn) in the secreted proteome. MeeF and MeeY copurify with proteins of the general secretory pathway, and in their absence the FtsH membrane protease is essential for viability. MeeF and MeeY are also required for efficient function of the Mn2+-dependent lipoteichoic acid synthase (LtaS), a membrane-localized enzyme with an extracytoplasmic active site. Thus, MeeF and MeeY, representative of the widely conserved TerC family of membrane transporters, function in the co-translocational metalation of Mn2+-dependent membrane and extracellular enzymes.
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Affiliation(s)
- Bixi He
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, NY, 14853-8101, USA
| | - Ankita J Sachla
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, NY, 14853-8101, USA
| | - John D Helmann
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, NY, 14853-8101, USA.
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5
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Jeong GJ, Khan F, Tabassum N, Cho KJ, Kim YM. Controlling biofilm and virulence properties of Gram-positive bacteria by targeting wall teichoic acid and lipoteichoic acid. Int J Antimicrob Agents 2023; 62:106941. [PMID: 37536571 DOI: 10.1016/j.ijantimicag.2023.106941] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 07/19/2023] [Accepted: 07/27/2023] [Indexed: 08/05/2023]
Abstract
Wall teichoic acid (WTA) and lipoteichoic acid (LTA) are structural components of Gram-positive bacteria's peptidoglycan and cell membrane, which are mostly anionic glycopolymers. WTA confers numerous physiological, virulence, and pathogenic features to bacterial pathogens. It controls cell shape, cell division, and the localisation of autolytic enzymes and ion homeostasis. In the context of virulence and pathogenicity, it aids bacterial cell attachment and colonisation and protects against the host defence system and antibiotics. Having such a broad function in pathogenic bacteria's lifecycle, WTA/LTA become one of the potential targets for antibacterial agents to reduce bacterial infection in the host. The number of reports for targeting the WTA/LTA pathway has risen, mostly by focusing on three distinct targets: antivirulence targets, β-lactam potentiator targets, and essential targets. The current review looked at the role of WTA/LTA in biofilm development and virulence in a range of Gram-positive pathogenic bacteria. Furthermore, alternate strategies, such as the application of natural and synthetic compounds that target the WTA/LTA pathway, have been thoroughly discussed. Moreover, the application of nanomaterials and a combination of drugs have also been discussed as a viable method for targeting the WTA/LTA in numerous Gram-positive bacteria. In addition, a future perspective for controlling bacterial infection by targeting the WTA/LTA is proposed.
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Affiliation(s)
- Geum-Jae Jeong
- Department of Food Science and Technology, Pukyong National University, Busan, Republic of Korea
| | - Fazlurrahman Khan
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea.
| | - Nazia Tabassum
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea
| | - Kyung-Jin Cho
- Department of Food Science and Technology, Pukyong National University, Busan, Republic of Korea
| | - Young-Mog Kim
- Department of Food Science and Technology, Pukyong National University, Busan, Republic of Korea; Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea.
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6
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Douglas EJA, Wulandari SW, Lovell SD, Laabei M. Novel antimicrobial strategies to treat multi-drug resistant Staphylococcus aureus infections. Microb Biotechnol 2023; 16:1456-1474. [PMID: 37178319 PMCID: PMC10281381 DOI: 10.1111/1751-7915.14268] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/12/2023] [Accepted: 04/18/2023] [Indexed: 05/15/2023] Open
Abstract
Antimicrobial resistance is a major obstacle for the treatment of infectious diseases and currently represents one of the most significant threats to global health. Staphylococcus aureus remains a formidable human pathogen with high mortality rates associated with severe systemic infections. S. aureus has become notorious as a multidrug resistant bacterium, which when combined with its extensive arsenal of virulence factors that exacerbate disease, culminates in an incredibly challenging pathogen to treat clinically. Compounding this major health issue is the lack of antibiotic discovery and development, with only two new classes of antibiotics approved for clinical use in the last 20 years. Combined efforts from the scientific community have reacted to the threat of dwindling treatment options to combat S. aureus disease in several innovative and exciting developments. This review describes current and future antimicrobial strategies aimed at treating staphylococcal colonization and/or disease, examining therapies that show significant promise at the preclinical development stage to approaches that are currently being investigated in clinical trials.
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7
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He B, Sachla AJ, Helmann JD. TerC Proteins Function During Protein Secretion to Metalate Exoenzymes. RESEARCH SQUARE 2023:rs.3.rs-2860473. [PMID: 37292672 PMCID: PMC10246235 DOI: 10.21203/rs.3.rs-2860473/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Cytosolic metalloenzymes acquire metals from buffered intracellular pools. How exported metalloenzymes are appropriately metalated is less clear. We provide evidence that TerC family proteins function in metalation of enzymes during export through the general secretion (Sec-dependent) pathway. Bacillus subtilis strains lacking MeeF(YceF) and MeeY(YkoY) have a reduced capacity for protein export and a greatly reduced level of manganese (Mn) in the secreted proteome. MeeF and MeeY copurify with proteins of the general secretory pathway, and in their absence the FtsH membrane protease is essential for viability. MeeF and MeeY are also required for efficient function of the Mn2+-dependent lipoteichoic acid synthase (LtaS), a membrane-localized enzyme with an extracytoplasmic active site. Thus, MeeF and MeeY, representative of the widely conserved TerC family of membrane transporters, function in the co-translocational metalation of Mn2+-dependent membrane and extracellular enzymes.
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Affiliation(s)
- Bixi He
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - Ankita J. Sachla
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - John D. Helmann
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
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8
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Serpi M, Pertusati F, Morozzi C, Novelli G, Giannantonio D, Duggan K, Vittorio S, Fallis IA, De Luca L, Williams D. Synthesis, molecular docking and antibacterial activity of an oxadiazole-based lipoteichoic acid inhibitor and its metabolites. J Mol Struct 2023; 1278:None. [PMID: 38312219 PMCID: PMC10836577 DOI: 10.1016/j.molstruc.2023.134977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 01/12/2023] [Accepted: 01/14/2023] [Indexed: 01/16/2023]
Abstract
Amongst drug resistant Gram-positive bacteria, Staphylococcus aureus is a pathogen of great concern as it is the leading cause of life-threatening nosocomial and community acquired infections which are often associated with implanted medical devices. The biosynthesis of lipotheicoic acid (LTA) by S. aureus has been recognized as a promising antibacterial target, owing its critical role in the growth and survival of Gram-positive bacteria. Here we report for the first time the chemical synthesis and characterisation of an oxadiazole based compound (1771), previously described as an inhibitor of LTA biosynthesis by targeting Lta synthase enzyme (LtaS). To investigate its controversial mode of action, we also performed molecular docking studies, which indicated that 1771 behaves as a competitive inhibitor against LtaS. We also synthesised and evaluated the antimicrobial activity of 1771 metabolites which we have identified from its decomposition in mouse serum, proving that the biological activity was caused by intact 1771.
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Affiliation(s)
- Michaela Serpi
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, Wales CF10 3AT, United Kingdom
| | - Fabrizio Pertusati
- School of Pharmacy and Pharmaceutical Sciences, Redwood Building, King Edwards VII avenue, Cardiff, Wales CF10 3NB, United Kingdom
| | - Chiara Morozzi
- School of Pharmacy and Pharmaceutical Sciences, Redwood Building, King Edwards VII avenue, Cardiff, Wales CF10 3NB, United Kingdom
| | - Giulia Novelli
- School of Pharmacy and Pharmaceutical Sciences, Redwood Building, King Edwards VII avenue, Cardiff, Wales CF10 3NB, United Kingdom
| | - Daniele Giannantonio
- School of Pharmacy and Pharmaceutical Sciences, Redwood Building, King Edwards VII avenue, Cardiff, Wales CF10 3NB, United Kingdom
| | - Katrina Duggan
- Oral and Biomedical Sciences, School of Dentistry, Cardiff University, Cardiff, United Kingdom
| | - Serena Vittorio
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno D'Alcontres 31, Messina I-98125, Italy
| | - Ian A. Fallis
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, Wales CF10 3AT, United Kingdom
| | - Laura De Luca
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno D'Alcontres 31, Messina I-98125, Italy
| | - David Williams
- Oral and Biomedical Sciences, School of Dentistry, Cardiff University, Cardiff, United Kingdom
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9
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He B, Sachla AJ, Helmann JD. TerC Proteins Function During Protein Secretion to Metalate Exoenzymes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.10.536223. [PMID: 37090602 PMCID: PMC10120614 DOI: 10.1101/2023.04.10.536223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Cytosolic metalloenzymes acquire metals from buffered intracellular pools. How exported metalloenzymes are appropriately metalated is less clear. We provide evidence that TerC family proteins function in metalation of enzymes during export through the general secretion (Sec-dependent) pathway. Bacillus subtilis strains lacking MeeF(YceF) and MeeY(YkoY) have a reduced capacity for protein export and a greatly reduced level of manganese (Mn) in the secreted proteome. MeeF and MeeY copurify with proteins of the general secretory pathway, and in their absence the FtsH membrane protease is essential for viability. MeeF and MeeY are also required for efficient function of the Mn 2+ -dependent lipoteichoic acid synthase (LtaS), a membrane-localized enzyme with an extracytoplasmic active site. Thus, MeeF and MeeY, representative of the widely conserved TerC family of membrane transporters, function in the co-translocational metalation of Mn 2+ -dependent membrane and extracellular enzymes.
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Affiliation(s)
- Bixi He
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - Ankita J. Sachla
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - John D. Helmann
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
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Kim SK, Im J, Ko EB, Lee D, Seo HS, Yun CH, Han SH. Lipoteichoic acid of Streptococcus gordonii as a negative regulator of human dendritic cell activation. Front Immunol 2023; 14:1056949. [PMID: 37056772 PMCID: PMC10086370 DOI: 10.3389/fimmu.2023.1056949] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 03/13/2023] [Indexed: 03/30/2023] Open
Abstract
Streptococcus gordonii, an opportunistic Gram-positive bacterium, causes an infective endocarditis that could be fatal to human health. Dendritic cells (DCs) are known to be involved in disease progression and immune responses in S. gordonii infection. Since lipoteichoic acid (LTA) is a representative virulence factor of S. gordonii, we here investigated its role in the activation of human DCs stimulated with LTA-deficient (ΔltaS) S. gordonii or S. gordonii LTA. DCs were differentiated from human blood-derived monocytes in the presence of GM-CSF and IL-4 for 6 days. DCs treated with heat-killed ΔltaS S. gordonii (ΔltaS HKSG) showed relatively higher binding and phagocytic activities than those treated with heat-killed wild-type S. gordonii (wild-type HKSG). Furthermore, ΔltaS HKSG was superior to wild-type HKSG in inducing phenotypic maturation markers including CD80, CD83, CD86, PD-L1, and PD-L2, antigen-presenting molecule MHC class II, and proinflammatory cytokines such as TNF-α and IL-6. Concomitantly, DCs treated with the ΔltaS HKSG induced better T cell activities, including proliferation and activation marker (CD25) expression, than those treated with the wild-type. LTA, but not lipoproteins, isolated from S. gordonii weakly activated TLR2 and barely affected the expression of phenotypic maturation markers or cytokines in DCs. Collectively, these results demonstrated that LTA is not a major immuno-stimulating agent of S. gordonii but rather it interferes with bacteria-induced DC maturation, suggesting its potential role in immune evasion.
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Affiliation(s)
- Sun Kyung Kim
- Department of Oral Microbiology and Immunology, and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Jintaek Im
- Department of Oral Microbiology and Immunology, and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Eun Byeol Ko
- Department of Oral Microbiology and Immunology, and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Dongwook Lee
- Department of Oral Microbiology and Immunology, and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Ho Seong Seo
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea
| | - Cheol-Heui Yun
- Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
- Institutes of Green-bio Science and Technology, Seoul National University, Pyeongchang, Gangwon-do, Republic of Korea
- Interdisciplinary Programs in Agricultural Genomics, Seoul National University, Seoul, Republic of Korea
| | - Seung Hyun Han
- Department of Oral Microbiology and Immunology, and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
- *Correspondence: Seung Hyun Han,
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11
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Anticryptococcal activity and mechanistic investigation of histidine-rich short peptides. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2022.134813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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12
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Aaghaz S, Sharma K, Maurya IK, Rudramurthy SM, Singh S, Kumar V, Tikoo K, Jain R. Synthetic amino acids-based short amphipathic peptides exhibit antifungal activity by targeting cell membrane disruption. Drug Dev Res 2023; 84:514-526. [PMID: 36757096 DOI: 10.1002/ddr.22041] [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: 11/03/2022] [Revised: 12/21/2022] [Accepted: 01/22/2023] [Indexed: 02/10/2023]
Abstract
Availability of a limited number of antifungal drugs created a necessity to develop new antifungals with distinct mode of action. Investigation on a new series of peptides led us to identify Boc-His-Trp-His[1-(4-tert-butylphenyl)] (10g) as the most promising inhibitor exhibiting IC50 value of 4.4 µg/mL against Cryptococcus neoformans. Analog 10g exhibit high selectivity to fungal cells and was nonhemolytic and noncytotoxic at its minimum inhibitory concentration. 10g produced fungicidal effect on growing cryptococcal cells and displayed synergistic effect with amphotericin B. Overall cationic character of 10g resulted in interaction with negatively charged fungal membrane while hydrophobicity enhanced penetration inside the cryptococcal cells causing hole(s) formation and disruption to the membrane as evident by the scanning electron microscopy, transmission electron microscopy, and confocal laser scanning microscopy analyses. Flow cytometric investigation revealed rapid death of fungal cells by apopotic pathway.
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Affiliation(s)
- Shams Aaghaz
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sahibzada Ajit Singh Nagar, Punjab, India
| | - Komal Sharma
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sahibzada Ajit Singh Nagar, Punjab, India
| | - Indresh K Maurya
- Center of Infectious Diseases, National Institute of Pharmaceutical Education and Research, Sahibzada Ajit Singh Nagar, Punjab, India
| | - Shivaprakash M Rudramurthy
- Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Shreya Singh
- Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Vinod Kumar
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sahibzada Ajit Singh Nagar, Punjab, India
| | - Kulbhushan Tikoo
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sahibzada Ajit Singh Nagar, Punjab, India
| | - Rahul Jain
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sahibzada Ajit Singh Nagar, Punjab, India.,Center of Infectious Diseases, National Institute of Pharmaceutical Education and Research, Sahibzada Ajit Singh Nagar, Punjab, India
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13
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Li X, Cai Y, Xia Q, Liao Y, Qin R. Antibacterial sensitizers from natural plants: A powerful weapon against methicillin-resistant Staphylococcus aureus. Front Pharmacol 2023; 14:1118793. [PMID: 36909155 PMCID: PMC9998539 DOI: 10.3389/fphar.2023.1118793] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 02/13/2023] [Indexed: 02/26/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a drug-resistant bacterium that can cause a range of infections with high morbidity and mortality, including pneumonia, etc. Therefore, development of new drugs or therapeutic strategies against MRSA is urgently needed. Increasing evidence has shown that combining antibiotics with "antibacterial sensitizers" which itself has no effect on MRSA, is highly effective against MRSA. Many studies showed the development of antibacterial sensitizers from natural plants may be a promising strategy against MRSA because of their low side effects, low toxicity and multi-acting target. In our paper, we first reviewed the resistance mechanisms of MRSA including "Resistance to Beta-Lactams", "Resistance to Glycopeptide antibiotics", "Resistance to Macrolides, Aminoglycosides, and Oxazolidinones" etc. Moreover, we summarized the possible targets for antibacterial sensitizers against MRSA. Furthermore, we reviewed the synergy effects of active monomeric compounds from natural plants combined with antibiotics against MRSA and their corresponding mechanisms over the last two decades. This review provides a novel approach to overcome antibiotic resistance in MRSA.
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Affiliation(s)
- Xiaoli Li
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing, China
| | - Yongqing Cai
- Department of Pharmacy, Daping Hospital, Army Medical University, Chongqing, China
| | - Qinchuan Xia
- Fuan Pharmaceutical Group Chongqing Bosen Pharmaceutical Co., Ltd., Chongqing, China
| | - Yongqun Liao
- Fuan Pharmaceutical Group Chongqing Bosen Pharmaceutical Co., Ltd., Chongqing, China
| | - Rongxin Qin
- Department of Pharmacology, College of Pharmacy, Army Medical University (The Third Military Medical University), Chongqing, China
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14
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Ye J, Chen X. Current Promising Strategies against Antibiotic-Resistant Bacterial Infections. Antibiotics (Basel) 2022; 12:antibiotics12010067. [PMID: 36671268 PMCID: PMC9854991 DOI: 10.3390/antibiotics12010067] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 12/27/2022] [Accepted: 12/28/2022] [Indexed: 12/31/2022] Open
Abstract
Infections caused by antibiotic-resistant bacteria (ARB) are one of the major global health challenges of our time. In addition to developing new antibiotics to combat ARB, sensitizing ARB, or pursuing alternatives to existing antibiotics are promising options to counter antibiotic resistance. This review compiles the most promising anti-ARB strategies currently under development. These strategies include the following: (i) discovery of novel antibiotics by modification of existing antibiotics, screening of small-molecule libraries, or exploration of peculiar places; (ii) improvement in the efficacy of existing antibiotics through metabolic stimulation or by loading a novel, more efficient delivery systems; (iii) development of alternatives to conventional antibiotics such as bacteriophages and their encoded endolysins, anti-biofilm drugs, probiotics, nanomaterials, vaccines, and antibody therapies. Clinical or preclinical studies show that these treatments possess great potential against ARB. Some anti-ARB products are expected to become commercially available in the near future.
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15
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Kepplinger B, Wen X, Tyler AR, Kim BY, Brown J, Banks P, Dashti Y, Mackenzie ES, Wills C, Kawai Y, Waldron KJ, Allenby NEE, Wu LJ, Hall MJ, Errington J. Mirubactin C rescues the lethal effect of cell wall biosynthesis mutations in Bacillus subtilis. Front Microbiol 2022; 13:1004737. [PMID: 36312962 PMCID: PMC9609785 DOI: 10.3389/fmicb.2022.1004737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/22/2022] [Indexed: 01/29/2023] Open
Abstract
Growth of most rod-shaped bacteria is accompanied by the insertion of new peptidoglycan into the cylindrical cell wall. This insertion, which helps maintain and determine the shape of the cell, is guided by a protein machine called the rod complex or elongasome. Although most of the proteins in this complex are essential under normal growth conditions, cell viability can be rescued, for reasons that are not understood, by the presence of a high (mM) Mg2+ concentration. We screened for natural product compounds that could rescue the growth of mutants affected in rod-complex function. By screening > 2,000 extracts from a diverse collection of actinobacteria, we identified a compound, mirubactin C, related to the known iron siderophore mirubactin A, which rescued growth in the low micromolar range, and this activity was confirmed using synthetic mirubactin C. The compound also displayed toxicity at higher concentrations, and this effect appears related to iron homeostasis. However, several lines of evidence suggest that the mirubactin C rescuing activity is not due simply to iron sequestration. The results support an emerging view that the functions of bacterial siderophores extend well beyond simply iron binding and uptake.
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Affiliation(s)
- Bernhard Kepplinger
- Centre for Bacterial Cell Biology, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Xin Wen
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Andrew Robert Tyler
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Byung-Yong Kim
- Odyssey Therapeutics Inc., Newcastle upon Tyne, United Kingdom
| | - James Brown
- Centre for Bacterial Cell Biology, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Peter Banks
- Faculty of Medical Sciences, Bioscience Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Yousef Dashti
- Centre for Bacterial Cell Biology, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Eilidh Sohini Mackenzie
- Faculty of Medical Sciences, Bioscience Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Corinne Wills
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Yoshikazu Kawai
- Centre for Bacterial Cell Biology, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Kevin John Waldron
- Faculty of Medical Sciences, Bioscience Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | - Ling Juan Wu
- Centre for Bacterial Cell Biology, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Michael John Hall
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jeff Errington
- Centre for Bacterial Cell Biology, Newcastle University, Newcastle upon Tyne, United Kingdom
- Odyssey Therapeutics Inc., Newcastle upon Tyne, United Kingdom
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16
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Jia HR, Zhu YX, Liu Y, Guo Y, Sayed SM, Zhu XY, Cheng X, Wu FG. Direct chemical editing of Gram-positive bacterial cell walls via an enzyme-catalyzed oxidative coupling reaction. EXPLORATION (BEIJING, CHINA) 2022; 2:20220010. [PMID: 37325504 PMCID: PMC10190971 DOI: 10.1002/exp.20220010] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 04/28/2022] [Indexed: 06/17/2023]
Abstract
Chemically manipulating bacterial surface structures, a cutting-edge research direction in the biomedical field, predominantly relies on metabolic labeling by now. However, this method may involve daunting precursor synthesis and only labels nascent surface structures. Here, we report a facile and rapid modification strategy based on a tyrosinase-catalyzed oxidative coupling reaction (TyOCR) for bacterial surface engineering. This strategy employs phenol-tagged small molecules and tyrosinase to initiate direct chemical modification of Gram-positive bacterial cell walls with high labeling efficiency, while Gram-negative bacteria are inert to this modification due to the hindrance of an outer membrane. By using the biotin‒avidin system, we further present the selective deposition of various materials, including photosensitizer, magnetic nanoparticle, and horseradish peroxidase, on Gram-positive bacterial surfaces, and realize the purification/isolation/enrichment and naked-eye detection of bacterial strains. This work demonstrates that TyOCR is a promising strategy for engineering live bacterial cells.
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Affiliation(s)
- Hao-Ran Jia
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering Southeast University Nanjing P. R. China
| | - Ya-Xuan Zhu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering Southeast University Nanjing P. R. China
| | - Yi Liu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering Southeast University Nanjing P. R. China
| | - Yuxin Guo
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering Southeast University Nanjing P. R. China
| | - Sayed Mir Sayed
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering Southeast University Nanjing P. R. China
| | - Xiao-Yu Zhu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering Southeast University Nanjing P. R. China
| | - Xiaotong Cheng
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering Southeast University Nanjing P. R. China
| | - Fu-Gen Wu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering Southeast University Nanjing P. R. China
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17
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Zhou J, Cai Y, Liu Y, An H, Deng K, Ashraf MA, Zou L, Wang J. Breaking down the cell wall: Still an attractive antibacterial strategy. Front Microbiol 2022; 13:952633. [PMID: 36212892 PMCID: PMC9544107 DOI: 10.3389/fmicb.2022.952633] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 08/18/2022] [Indexed: 11/17/2022] Open
Abstract
Since the advent of penicillin, humans have known about and explored the phenomenon of bacterial inhibition via antibiotics. However, with changes in the global environment and the abuse of antibiotics, resistance mechanisms have been selected in bacteria, presenting huge threats and challenges to the global medical and health system. Thus, the study and development of new antimicrobials is of unprecedented urgency and difficulty. Bacteria surround themselves with a cell wall to maintain cell rigidity and protect against environmental insults. Humans have taken advantage of antibiotics to target the bacterial cell wall, yielding some of the most widely used antibiotics to date. The cell wall is essential for bacterial growth and virulence but is absent from humans, remaining a high-priority target for antibiotic screening throughout the antibiotic era. Here, we review the extensively studied targets, i.e., MurA, MurB, MurC, MurD, MurE, MurF, Alr, Ddl, MurI, MurG, lipid A, and BamA in the cell wall, starting from the very beginning to the latest developments to elucidate antimicrobial screening. Furthermore, recent advances, including MraY and MsbA in peptidoglycan and lipopolysaccharide, and tagO, LtaS, LspA, Lgt, Lnt, Tol-Pal, MntC, and OspA in teichoic acid and lipoprotein, have also been profoundly discussed. The review further highlights that the application of new methods such as macromolecular labeling, compound libraries construction, and structure-based drug design will inspire researchers to screen ideal antibiotics.
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Affiliation(s)
- Jingxuan Zhou
- The People’s Hospital of China Three Gorges University, Yichang, Hubei, China
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang, Hubei, China
- The Institute of Infection and Inflammation, College of Basic Medical Sciences, China Three Gorges University, Yichang, Hubei, China
| | - Yi Cai
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang, Hubei, China
- The Institute of Infection and Inflammation, College of Basic Medical Sciences, China Three Gorges University, Yichang, Hubei, China
| | - Ying Liu
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang, Hubei, China
- The Institute of Infection and Inflammation, College of Basic Medical Sciences, China Three Gorges University, Yichang, Hubei, China
| | - Haoyue An
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang, Hubei, China
- The Institute of Infection and Inflammation, College of Basic Medical Sciences, China Three Gorges University, Yichang, Hubei, China
| | - Kaihong Deng
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang, Hubei, China
- The Institute of Infection and Inflammation, College of Basic Medical Sciences, China Three Gorges University, Yichang, Hubei, China
| | - Muhammad Awais Ashraf
- Department of Microbiology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Lili Zou
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang, Hubei, China
- The Institute of Infection and Inflammation, College of Basic Medical Sciences, China Three Gorges University, Yichang, Hubei, China
| | - Jun Wang
- The People’s Hospital of China Three Gorges University, Yichang, Hubei, China
- *Correspondence: Jun Wang,
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18
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Antimicrobial Activity of Rhenium Di- and Tricarbonyl Diimine Complexes: Insights on Membrane-Bound S. aureus Protein Binding. Pharmaceuticals (Basel) 2022; 15:ph15091107. [PMID: 36145328 PMCID: PMC9501577 DOI: 10.3390/ph15091107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/31/2022] [Accepted: 08/31/2022] [Indexed: 11/16/2022] Open
Abstract
Antimicrobial resistance is one of the major human health threats, with significant impacts on the global economy. Antibiotics are becoming increasingly ineffective as drug-resistance spreads, imposing an urgent need for new and innovative antimicrobial agents. Metal complexes are an untapped source of antimicrobial potential. Rhenium complexes, amongst others, are particularly attractive due to their low in vivo toxicity and high antimicrobial activity, but little is known about their targets and mechanism of action. In this study, a series of rhenium di- and tricarbonyl diimine complexes were prepared and evaluated for their antimicrobial potential against eight different microorganisms comprising Gram-negative and -positive bacteria. Our data showed that none of the Re dicarbonyl or neutral tricarbonyl species have either bactericidal or bacteriostatic potential. In order to identify possible targets of the molecules, and thus possibly understand the observed differences in the antimicrobial efficacy of the molecules, we computationally evaluated the binding affinity of active and inactive complexes against structurally characterized membrane-bound S. aureus proteins. The computational analysis indicates two possible major targets for this class of compounds, namely lipoteichoic acids flippase (LtaA) and lipoprotein signal peptidase II (LspA). Our results, consistent with the published in vitro studies, will be useful for the future design of rhenium tricarbonyl diimine-based antibiotics.
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19
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Abstract
Dental caries is a multifactorial biofilm- and sugar-dependent disease. This study investigated the influence of different agents on the induction of surviving Streptococcus mutans cells after successive treatment cycles and characterized the biofilms formed by these cells recovered posttreatment. The agents (with their main targets listed in parentheses) were compound 1771 (lipoteichoic acids), 4′ hydroxychalcone (exopolysaccharides), myricetin (exopolysaccharides), tt-farnesol (cytoplasmatic membrane), sodium fluoride (enolase—glycolysis), chlorhexidine (antimicrobial), and vehicle. Recovered cells from biofilms were generated from exposure to each agent during 10 cycles of consecutive treatments (modeled on a polystyrene plate bottom). The recovered cell counting was different for each agent. The recovered cells from each group were grown as biofilms on saliva-coated hydroxyapatite discs (culture medium with sucrose/starch). In S. mutans biofilms formed by cells recovered from biofilms previously exposed to compound 1771, 4′ hydroxychalcone, or myricetin, cells presented higher expression of the 16S rRNA, gyrA (DNA replication and transcription), gtfB (insoluble exopolysaccharides), and eno (enolase—glycolysis) genes and lower quantities of insoluble dry weight and insoluble exopolysaccharides than those derived from other agents. These findings were confirmed by the smaller biovolume of bacteria and/or exopolysaccharides and the biofilm distribution (coverage area). Moreover, preexposure to chlorhexidine increased exopolysaccharide production. Therefore, agents with different targets induce cells with distinct biofilm formation capacities, which is critical for developing formulations for biofilm control. IMPORTANCE This article addresses the effect of distinct agents with distinct targets in the bacterial cell (cytoplasmatic membrane and glycolysis), the cell’s extracellular synthesis of exopolysaccharides that are important for cariogenic extracellular matrix construction and biofilm buildup in the generation of cells that persisted after treatment, and how these cells form biofilms in vitro. For example, if preexposure to an agent augments the production of virulence determinants, such as exopolysaccharides, its clinical value may be inadequate. Modification of biofilm formation capacity after exposure to agents is critical for the development of formulations for biofilm control to prevent caries, a ubiquitous disease associated with biofilm and diet.
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20
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Chee Wezen X, Chandran A, Eapen RS, Waters E, Bricio-Moreno L, Tosi T, Dolan S, Millership C, Kadioglu A, Gründling A, Itzhaki LS, Welch M, Rahman T. Structure-Based Discovery of Lipoteichoic Acid Synthase Inhibitors. J Chem Inf Model 2022; 62:2586-2599. [PMID: 35533315 PMCID: PMC9131456 DOI: 10.1021/acs.jcim.2c00300] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Indexed: 01/20/2023]
Abstract
Lipoteichoic acid synthase (LtaS) is a key enzyme for the cell wall biosynthesis of Gram-positive bacteria. Gram-positive bacteria that lack lipoteichoic acid (LTA) exhibit impaired cell division and growth defects. Thus, LtaS appears to be an attractive antimicrobial target. The pharmacology around LtaS remains largely unexplored with only two small-molecule LtaS inhibitors reported, namely "compound 1771" and the Congo red dye. Structure-based drug discovery efforts against LtaS remain unattempted due to the lack of an inhibitor-bound structure of LtaS. To address this, we combined the use of a molecular docking technique with molecular dynamics (MD) simulations to model a plausible binding mode of compound 1771 to the extracellular catalytic domain of LtaS (eLtaS). The model was validated using alanine mutagenesis studies combined with isothermal titration calorimetry. Additionally, lead optimization driven by our computational model resulted in an improved version of compound 1771, namely, compound 4 which showed greater affinity for binding to eLtaS than compound 1771 in biophysical assays. Compound 4 reduced LTA production in S. aureus dose-dependently, induced aberrant morphology as seen for LTA-deficient bacteria, and significantly reduced bacteria titers in the lung of mice infected with S. aureus. Analysis of our MD simulation trajectories revealed the possible formation of a transient cryptic pocket in eLtaS. Virtual screening (VS) against the cryptic pocket led to the identification of a new class of inhibitors that could potentiate β-lactams against methicillin-resistant S. aureus. Our overall workflow and data should encourage further drug design campaign against LtaS. Finally, our work reinforces the importance of considering protein conformational flexibility to a successful VS endeavor.
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Affiliation(s)
- Xavier Chee Wezen
- Science
Program, School of Chemical Engineering and Science, Faculty of Engineering,
Computing and Science, Swinburne University
of Technology Sarawak, Kuching 93350, Malaysia
| | - Aneesh Chandran
- Department
of Biotechnology & Microbiology, Kannur
University, Kannur 670 661, Kerala, India
| | | | - Elaine Waters
- Department
of Clinical Infection Microbiology and Immunology, Institute of Infection
and Global Health, University of Liverpool, Liverpool L69 7BE, U.K.
| | - Laura Bricio-Moreno
- Department
of Clinical Infection Microbiology and Immunology, Institute of Infection
and Global Health, University of Liverpool, Liverpool L69 7BE, U.K.
| | - Tommaso Tosi
- Section
of Molecular Microbiology and MRC Centre for Molecular Bacteriology
and Infection, Imperial College London, London SW7 2AZ, U.K.
| | - Stephen Dolan
- Department
of Biochemistry, University of Cambridge, Cambridge CB2 1QW, U.K.
| | - Charlotte Millership
- Section
of Molecular Microbiology and MRC Centre for Molecular Bacteriology
and Infection, Imperial College London, London SW7 2AZ, U.K.
| | - Aras Kadioglu
- Department
of Clinical Infection Microbiology and Immunology, Institute of Infection
and Global Health, University of Liverpool, Liverpool L69 7BE, U.K.
| | - Angelika Gründling
- Section
of Molecular Microbiology and MRC Centre for Molecular Bacteriology
and Infection, Imperial College London, London SW7 2AZ, U.K.
| | - Laura S. Itzhaki
- Department
of PharmacologyUniversity of CambridgeCambridgeCB2 1PDU.K.
| | - Martin Welch
- Department
of Biochemistry, University of Cambridge, Cambridge CB2 1QW, U.K.
| | - Taufiq Rahman
- Department
of PharmacologyUniversity of CambridgeCambridgeCB2 1PDU.K.
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21
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Roncari Rocha G, Sims KR, Xiao B, Klein MI, Benoit DSW. Nanoparticle carrier co-delivery of complementary antibiofilm drugs abrogates dual species cariogenic biofilm formation in vitro. J Oral Microbiol 2021; 14:1997230. [PMID: 34868474 PMCID: PMC8635615 DOI: 10.1080/20002297.2021.1997230] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Background Dental caries is a multifactorial disease caused by pathogenic biofilm. In particular, Streptococcus mutans synthesizes biofilm exopolysaccharides, while Candida albicans is associated with the development of severe carious lesions. Aim This study aimed to prevent the formation of S. mutans and C. albicans biofilms by exploiting pH-sensitive nanoparticle carriers (NPCs) with high affinity to exopolysaccharides to increase the substantivity of multi-targeted antibiofilm drugs introduced topically in vitro. Methods Dual-species biofilms were grown on saliva-coated hydroxyapatite discs with sucrose. Twice-daily, 1.5 min topical treatment regimens of unloaded and drug-loaded NPC were used. Drugs included combinations of two or three compounds with distinct, complementary antibiofilm targets: tt-farnesol (terpenoid; bacterial acid tolerance, fungal quorum sensing), myricetin (flavonoid; exopolysaccharides inhibitor), and 1771 (lipoteichoic acid inhibitor; bacterial adhesion and co-aggregation). Biofilms were evaluated for biomass, microbial population, and architecture. Results NPC delivering tt-farnesol and 1771 with or without myricetin completely prevented biofilm formation by impeding biomass accumulation, bacterial and fungal population growth, and exopolysaccharide matrix deposition (vs. control unloaded NPC). Both formulations hindered acid production, maintaining the pH of spent media above the threshold for enamel demineralization. However, treatments had no effect on pre-established dual-species biofilms. Conclusion Complementary antibiofilm drug-NPC treatments prevented biofilm formation by targeting critical virulence factors of acidogenicity and exopolysaccharides synthesis.
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Affiliation(s)
- Guilherme Roncari Rocha
- Department of Dental Materials and Prosthodontics, São Paulo State University, São Paulo, Brazil.,Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA
| | - Kenneth R Sims
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA
| | - Baixue Xiao
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA
| | - Marlise I Klein
- Department of Dental Materials and Prosthodontics, São Paulo State University, São Paulo, Brazil
| | - Danielle S W Benoit
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA.,Materials Science Program, University of Rochester, Ny, USA.,Department of Orthopaedics and Center for Musculoskeletal Research, University of Rochester, Ny, USA.,Center for Oral Biology, University of Rochester, NY, USA.,Department of Chemical Engineering, University of Rochester, Ny, USA
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22
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Pharmacokinetics of Azalomycin F, a Natural Macrolide Produced by Streptomycete Strains, in Rats. Molecules 2021; 26:molecules26216464. [PMID: 34770873 PMCID: PMC8588360 DOI: 10.3390/molecules26216464] [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] [Received: 10/04/2021] [Revised: 10/23/2021] [Accepted: 10/24/2021] [Indexed: 12/05/2022] Open
Abstract
As antimicrobial resistance has been increasing, new antimicrobial agents are desperately needed. Azalomycin F, a natural polyhydroxy macrolide, presents remarkable antimicrobial activities. To investigate its pharmacokinetic characteristics in rats, the concentrations of azalomycin F contained in biological samples, in vitro, were determined using a validated high-performance liquid chromatography–ultraviolet (HPLC-UV) method, and, in vivo, samples were assayed by an ultra-high performance liquid chromatography–tandem mass spectrometric (UPLC–MS/MS) method. Based on these methods, the pharmacokinetics of azalomycin F were first investigated. Its plasma concentration-time courses and pharmacokinetic parameters in rats were obtained by a non-compartment model for oral (26.4 mg/kg) and intravenous (2.2 mg/kg) administrations. The results indicate that the oral absolute bioavailability of azalomycin F is very low (2.39 ± 1.28%). From combinational analyses of these pharmacokinetic parameters, and of the results of the in-vitro absorption and metabolism experiments, we conclude that azalomycin F is absorbed relatively slowly and with difficulty by the intestinal tract, and subsequently can be rapidly distributed into the tissues and/or intracellular f of rats. Azalomycin F is stable in plasma, whole blood, and the liver, and presents plasma protein binding ratios of more than 90%. Moreover, one of the major elimination routes of azalomycin F is its excretion through bile and feces. Together, the above indicate that azalomycin F is suitable for administration by intravenous injection when used for systemic diseases, while, by oral administration, it can be used in the treatment of diseases of the gastrointestinal tract.
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23
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Bæk KT, Jensen C, Farha MA, Nielsen TK, Paknejadi E, Mebus VH, Vestergaard M, Brown ED, Frees D. A Staphylococcus aureus clpX Mutant Used as a Unique Screening Tool to Identify Cell Wall Synthesis Inhibitors that Reverse β-Lactam Resistance in MRSA. Front Mol Biosci 2021; 8:691569. [PMID: 34150853 PMCID: PMC8212132 DOI: 10.3389/fmolb.2021.691569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 05/14/2021] [Indexed: 11/17/2022] Open
Abstract
Staphylococcus aureus is a leading cause of bacterial infections world-wide. Staphylococcal infections are preferentially treated with β-lactam antibiotics, however, methicillin-resistant S. aureus (MRSA) strains have acquired resistance to this superior class of antibiotics. We have developed a growth-based, high-throughput screening approach that directly identifies cell wall synthesis inhibitors capable of reversing β-lactam resistance in MRSA. The screen is based on the finding that S. aureus mutants lacking the ClpX chaperone grow very poorly at 30°C unless specific steps in teichoic acid synthesis or penicillin binding protein (PBP) activity are inhibited. This property allowed us to exploit the S. aureus clpX mutant as a unique screening tool to rapidly identify biologically active compounds that target cell wall synthesis. We tested a library of ∼50,000 small chemical compounds and searched for compounds that inhibited growth of the wild type while stimulating growth of the clpX mutant. Fifty-eight compounds met these screening criteria, and preliminary tests of 10 compounds identified seven compounds that reverse β-lactam resistance of MRSA as expected for inhibitors of teichoic acid synthesis. The hit compounds are therefore promising candidates for further development as novel combination agents to restore β-lactam efficacy against MRSA.
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Affiliation(s)
- Kristoffer T Bæk
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Camilla Jensen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maya A Farha
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - Tobias K Nielsen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ervin Paknejadi
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Viktor H Mebus
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Martin Vestergaard
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Eric D Brown
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - Dorte Frees
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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24
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Gram Positive Bacterial Lipoteichoic Acid Role in a Root Canal Infection – A Literature Review. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2021. [DOI: 10.22207/jpam.15.2.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria and its by-products are found to be the main cause of pulpal and periapical infection of tooth. Infected root canals of tooth harbours a wide variation of microbial flora that includes both Gram-positive and Gram-negative microorganisms. Bacterial components such as Lipopolysaccharide (LPS) of gram negative bacteria and Lipoteichoic Acid (LTA) of gram positive bacteria have the potential to enter the peri-apical tissue of tooth and initiate the inflammatory process. After microbial death that occurs either due to body’s defence cells or by antibiotic action, bacterial cell wall components such as LTA are released which can persist inside macrophages for prolonged periods causing chronic inflammation. Once these cell-wall components are recognized by the body immune surveillance cells, numerous inflammatory mediators are released leading to inflammation and subsequent pathological consequences. The purpose of this review is intend to summarize the role of gram positive bacterial component LTA in causing endodontic infection and use of potential therapeutic agents against LTA.
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Zhang R, Shebes MA, Kho K, Scaffidi SJ, Meredith TC, Yu W. Spatial regulation of protein A in Staphylococcus aureus. Mol Microbiol 2021; 116:589-605. [PMID: 33949015 DOI: 10.1111/mmi.14734] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 12/31/2022]
Abstract
Surface proteins of Staphylococcus aureus play vital roles in bacterial physiology and pathogenesis. Recent work suggests that surface proteins are spatially regulated by a YSIRK/GXXS signal peptide that promotes cross-wall targeting at the mid-cell, though the mechanisms remain unclear. We previously showed that protein A (SpA), a YSIRK/GXXS protein and key staphylococcal virulence factor, mis-localizes in a ltaS mutant deficient in lipoteichoic acid (LTA) production. Here, we identified that SpA contains another cross-wall targeting signal, the LysM domain, which, in addition to the YSIRK/GXXS signal peptide, significantly enhances SpA cross-wall targeting. We show that LTA synthesis, but not LtaS, is required for SpA septal anchoring and cross-wall deposition. Interestingly, LTA is predominantly found at the peripheral cell membrane and is diminished at the septum of dividing staphylococcal cells, suggesting a restriction mechanism for SpA septal localization. Finally, we show that D-alanylation of LTA abolishes SpA cross-wall deposition by disrupting SpA distribution in the peptidoglycan layer without altering SpA septal anchoring. Our study reveals that multiple factors contribute to the spatial regulation and cross-wall targeting of SpA via different mechanisms, which coordinately ensures efficient incorporation of surface proteins into the growing peptidoglycan during the cell cycle.
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Affiliation(s)
- Ran Zhang
- Department of Cell Biology, Microbiology and Molecular Biology (CMMB), University of South Florida, Tampa, FL, USA
| | - Mac A Shebes
- Department of Cell Biology, Microbiology and Molecular Biology (CMMB), University of South Florida, Tampa, FL, USA
| | - Kelvin Kho
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Salvatore J Scaffidi
- Department of Cell Biology, Microbiology and Molecular Biology (CMMB), University of South Florida, Tampa, FL, USA
| | - Timothy C Meredith
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Wenqi Yu
- Department of Cell Biology, Microbiology and Molecular Biology (CMMB), University of South Florida, Tampa, FL, USA
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Compounds with Distinct Targets Present Diverse Antimicrobial and Antibiofilm Efficacy against Candida albicans and Streptococcus mutans, and Combinations of Compounds Potentiate Their Effect. J Fungi (Basel) 2021; 7:jof7050340. [PMID: 33924814 PMCID: PMC8146248 DOI: 10.3390/jof7050340] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/16/2021] [Accepted: 04/25/2021] [Indexed: 12/13/2022] Open
Abstract
Candida albicans and Streptococcus mutans interact synergistically in biofilms associated with a severe form of dental caries. Their synergism is driven by dietary sucrose. Thus, it is necessary to devise strategies to hinder the development of those biofilms and prevent cavities. Six compounds [tt-farnesol (sesquiterpene alcohol that decreases the bacterium acidogenicity and aciduricity and a quorum sensing fungal molecule), myricetin (flavonoid that interferes with S. mutans exopolysaccharides production), two 2'-hydroxychalcones and 4'-hydroxychalcone (intermediate metabolites for flavonoids), compound 1771 (inhibitor of lipoteichoic synthase in Gram-positive bacteria)] with targets in both fungus and bacterium and their products were investigated for their antimicrobial and antibiofilm activities against single-species cultures. The compounds and concentrations effective on single-species biofilms were tested alone and combined with or without fluoride to control initial and pre-formed dual-species biofilms. All the selected treatments eliminated both species on initial biofilms. In contrast, some combinations eliminated the bacterium and others the fungus in pre-formed biofilms. The combinations 4'-hydroxychalcone+tt-farnesol+myricetin, 4'-hydroxychalcone+tt-farnesol+fluoride, and all compounds together with fluoride were effective against both species in pre-formed biofilms. Therefore, combinations of compounds with distinct targets can prevent C. albicans and S. mutans dual-species biofilm build-up in vitro.
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Fisher JF, Mobashery S. β-Lactams against the Fortress of the Gram-Positive Staphylococcus aureus Bacterium. Chem Rev 2021; 121:3412-3463. [PMID: 33373523 PMCID: PMC8653850 DOI: 10.1021/acs.chemrev.0c01010] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The biological diversity of the unicellular bacteria-whether assessed by shape, food, metabolism, or ecological niche-surely rivals (if not exceeds) that of the multicellular eukaryotes. The relationship between bacteria whose ecological niche is the eukaryote, and the eukaryote, is often symbiosis or stasis. Some bacteria, however, seek advantage in this relationship. One of the most successful-to the disadvantage of the eukaryote-is the small (less than 1 μm diameter) and nearly spherical Staphylococcus aureus bacterium. For decades, successful clinical control of its infection has been accomplished using β-lactam antibiotics such as the penicillins and the cephalosporins. Over these same decades S. aureus has perfected resistance mechanisms against these antibiotics, which are then countered by new generations of β-lactam structure. This review addresses the current breadth of biochemical and microbiological efforts to preserve the future of the β-lactam antibiotics through a better understanding of how S. aureus protects the enzyme targets of the β-lactams, the penicillin-binding proteins. The penicillin-binding proteins are essential enzyme catalysts for the biosynthesis of the cell wall, and understanding how this cell wall is integrated into the protective cell envelope of the bacterium may identify new antibacterials and new adjuvants that preserve the efficacy of the β-lactams.
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Affiliation(s)
- Jed F Fisher
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame Indiana 46556, United States
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame Indiana 46556, United States
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Streptococcus pneumoniae, S. mitis, and S. oralis Produce a Phosphatidylglycerol-Dependent, ltaS-Independent Glycerophosphate-Linked Glycolipid. mSphere 2021; 6:6/1/e01099-20. [PMID: 33627509 PMCID: PMC8544892 DOI: 10.1128/msphere.01099-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Lipoteichoic acid (LTA) is a Gram-positive bacterial cell surface polymer that participates in host-microbe interactions. It was previously reported that the major human pathogen Streptococcus pneumoniae and the closely related oral commensals S. mitis and S. oralis produce type IV LTAs. Herein, using liquid chromatography/mass spectrometry-based lipidomic analysis, we found that in addition to type IV LTA biosynthetic precursors, S. mitis, S. oralis, and S. pneumoniae also produce glycerophosphate (Gro-P)-linked dihexosyl (DH)-diacylglycerol (DAG), which is a biosynthetic precursor of type I LTA. cdsA and pgsA mutants produce DHDAG but lack (Gro-P)-DHDAG, indicating that the Gro-P moiety is derived from phosphatidylglycerol (PG), whose biosynthesis requires these genes. S. mitis, but not S. pneumoniae or S. oralis, encodes an ortholog of the PG-dependent type I LTA synthase, ltaS. By heterologous expression analyses, we confirmed that S. mitisltaS confers poly(Gro-P) synthesis in both Escherichia coli and Staphylococcus aureus and that S. mitisltaS can rescue the growth defect of an S. aureusltaS mutant. However, we do not detect a poly(Gro-P) polymer in S. mitis using an anti-type I LTA antibody. Moreover, Gro-P-linked DHDAG is still synthesized by an S. mitisltaS mutant, demonstrating that S. mitis LtaS does not catalyze Gro-P transfer to DHDAG. Finally, an S. mitisltaS mutant has increased sensitivity to human serum, demonstrating that ltaS confers a beneficial but currently undefined function in S. mitis. Overall, our results demonstrate that S. mitis, S. pneumoniae, and S. oralis produce a Gro-P-linked glycolipid via a PG-dependent, ltaS-independent mechanism. IMPORTANCE The cell wall is a critical structural component of bacterial cells that confers important physiological functions. For pathogens, it is a site of host-pathogen interactions. In this work, we analyze the glycolipids synthesized by the mitis group streptococcal species, S. pneumoniae, S. oralis, and S. mitis. We find that all produce the glycolipid, glycerophosphate (Gro-P)-linked dihexosyl (DH)-diacylglycerol (DAG), which is a precursor for the cell wall polymer type I lipoteichoic acid in other bacteria. We investigate whether the known enzyme for type I LTA synthesis, LtaS, plays a role in synthesizing this molecule in S. mitis. Our results indicate that a novel mechanism is responsible. Our results are significant because they identify a novel feature of S. pneumoniae, S. oralis, and S. mitis glycolipid biology.
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Multiple ways to kill bacteria via inhibiting novel cell wall or membrane targets. Future Med Chem 2020; 12:1253-1279. [PMID: 32538147 DOI: 10.4155/fmc-2020-0046] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The rise of antibiotic-resistant infections has been well documented and the need for novel antibiotics cannot be overemphasized. US FDA approved antibiotics target only a small fraction of bacterial cell wall or membrane components, well-validated antimicrobial targets. In this review, we highlight small molecules that inhibit relatively unexplored cell wall and membrane targets. Some of these targets include teichoic acids-related proteins (DltA, LtaS, TarG and TarO), lipid II, Mur family enzymes, components of LPS assembly (MsbA, LptA, LptB and LptD), penicillin-binding protein 2a in methicillin-resistant Staphylococcus aureus, outer membrane protein transport (such as LepB and BamA) and lipoprotein transport components (LspA, LolC, LolD and LolE). Inhibitors of SecA, cell division protein, FtsZ and compounds that kill persister cells via membrane targeting are also covered.
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Kim SM, Escorbar I, Lee K, Fuchs BB, Mylonakis E, Kim W. Anti-MRSA agent discovery using Caenorhabditis elegans-based high-throughput screening. J Microbiol 2020; 58:431-444. [PMID: 32462486 DOI: 10.1007/s12275-020-0163-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/04/2020] [Accepted: 05/06/2020] [Indexed: 12/17/2022]
Abstract
Staphylococcus aureus is a leading cause of hospital- and community-acquired infections. Despite current advances in antimicrobial chemotherapy, the infections caused by S. aureus remain challenging due to their ability to readily develop resistance. Indeed, antibiotic resistance, exemplified by methicillin-resistant S. aureus (MRSA) is a top threat to global health security. Furthermore, the current rate of antibiotic discovery is much slower than the rate of antibiotic-resistance development. It seems evident that the conventional in vitro bacterial growth-based screening strategies can no longer effectively supply new antibiotics at the rate needed to combat bacterial antibiotic-resistance. To overcome this antibiotic resistance crisis, screening assays based on host-pathogen interactions have been developed. In particular, the free-living nematode Caenorhabditis elegans has been used for drug screening against MRSA. In this review, we will discuss the general principles of the C. elegans-based screening platform and will highlight its unique strengths by comparing it with conventional antibiotic screening platforms. We will outline major hits from high-throughput screens of more than 100,000 small molecules using the C. elegans-MRSA infection assay and will review the mode-of-action of the identified hit compounds. Lastly, we will discuss the potential of a C. elegans-based screening strategy as a paradigm shift screening platform.
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Affiliation(s)
- Soo Min Kim
- College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Iliana Escorbar
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, 02903, USA
| | - Kiho Lee
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, 02903, USA
| | - Beth Burgwyn Fuchs
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, 02903, USA
| | - Eleftherios Mylonakis
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, 02903, USA
| | - Wooseong Kim
- College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, 03760, Republic of Korea.
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Wenzel CQ, Mills DC, Dobruchowska JM, Vlach J, Nothaft H, Nation P, Azadi P, Melville SB, Carlson RW, Feldman MF, Szymanski CM. An atypical lipoteichoic acid from Clostridium perfringens elicits a broadly cross-reactive and protective immune response. J Biol Chem 2020; 295:9513-9530. [PMID: 32424044 DOI: 10.1074/jbc.ra119.009978] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 05/02/2020] [Indexed: 12/14/2022] Open
Abstract
Clostridium perfringens is a leading cause of food-poisoning and causes avian necrotic enteritis, posing a significant problem to both the poultry industry and human health. No effective vaccine against C. perfringens is currently available. Using an antiserum screen of mutants generated from a C. perfringens transposon-mutant library, here we identified an immunoreactive antigen that was lost in a putative glycosyltransferase mutant, suggesting that this antigen is likely a glycoconjugate. Following injection of formalin-fixed whole cells of C. perfringens HN13 (a laboratory strain) and JGS4143 (chicken isolate) intramuscularly into chickens, the HN13-derived antiserum was cross-reactive in immunoblots with all tested 32 field isolates, whereas only 5 of 32 isolates were recognized by JGS4143-derived antiserum. The immunoreactive antigens from both HN13 and JGS4143 were isolated, and structural analysis by MALDI-TOF-MS, GC-MS, and 2D NMR revealed that both were atypical lipoteichoic acids (LTAs) with poly-(β1→4)-ManNAc backbones substituted with phosphoethanolamine. However, although the ManNAc residues in JGS4143 LTA were phosphoethanolamine-modified, a few of these residues were instead modified with phosphoglycerol in the HN13 LTA. The JGS4143 LTA also had a terminal ribose and ManNAc instead of ManN in the core region, suggesting that these differences may contribute to the broadly cross-reactive response elicited by HN13. In a passive-protection chicken experiment, oral challenge with C. perfringens JGS4143 lead to 22% survival, whereas co-gavage with JGS4143 and α-HN13 antiserum resulted in 89% survival. This serum also induced bacterial killing in opsonophagocytosis assays, suggesting that HN13 LTA is an attractive target for future vaccine-development studies.
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Affiliation(s)
- Cory Q Wenzel
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,VaxAlta Inc., Edmonton, Alberta, Canada.,Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Dominic C Mills
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | | | - Jiri Vlach
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Harald Nothaft
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,VaxAlta Inc., Edmonton, Alberta, Canada.,Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Patrick Nation
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Stephen B Melville
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Russell W Carlson
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Mario F Feldman
- VaxAlta Inc., Edmonton, Alberta, Canada.,Department of Molecular Microbiology, Washington University of Medicine, St. Louis, Missouri, USA
| | - Christine M Szymanski
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada .,VaxAlta Inc., Edmonton, Alberta, Canada.,Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada.,Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
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Lipoteichoic Acid Biosynthesis Inhibitors as Potent Inhibitors of S. aureus and E. faecalis Growth and Biofilm Formation. Molecules 2020; 25:molecules25102277. [PMID: 32408616 PMCID: PMC7287929 DOI: 10.3390/molecules25102277] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/04/2020] [Accepted: 05/06/2020] [Indexed: 01/04/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE) have been deemed as serious threats by the CDC. Many chronic MRSA and VRE infections are due to biofilm formation. Biofilm are considered to be between 10–10,000 times more resistant to antibiotics, and therefore new chemical entities that inhibit and/or eradicate biofilm formation are needed. Teichoic acids, such as lipoteichoic acids (LTAs) and wall teichoic acids (WTAs), play pivotal roles in Gram-positive bacteria’s ability to grow, replicate, and form biofilms, making the inhibition of these teichoic acids a promising approach to fight infections by biofilm forming bacteria. Here, we describe the potent biofilm inhibition activity against MRSA and VRE biofilms by two LTA biosynthesis inhibitors HSGN-94 and HSGN-189 with MBICs as low as 0.0625 µg/mL against MRSA biofilms and 0.5 µg/mL against VRE biofilms. Additionally, both HSGN-94 and HSGN-189 were shown to potently synergize with the WTA inhibitor Tunicamycin in inhibiting MRSA and VRE biofilm formation.
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Modulation of Lipoteichoic Acids and Exopolysaccharides Prevents Streptococcus mutans Biofilm Accumulation. Molecules 2020; 25:molecules25092232. [PMID: 32397430 PMCID: PMC7249192 DOI: 10.3390/molecules25092232] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/02/2020] [Accepted: 05/05/2020] [Indexed: 11/19/2022] Open
Abstract
Dental caries is a diet–biofilm-dependent disease. Streptococcus mutans contributes to cariogenic biofilms by producing an extracellular matrix rich in exopolysaccharides and acids. The study aimed to determine the effect of topical treatments with compound 1771 (modulates lipoteichoic acid (LTA) metabolism) and myricetin (affects the synthesis of exopolysaccharides) on S. mutans biofilms. In vitro S. mutans UA159 biofilms were grown on saliva-coated hydroxyapatite discs, alternating 0.1% sucrose and 0.5% sucrose plus 1% starch. Twice-daily topical treatments were performed with both agents alone and combined with and without fluoride: compound 1771 (2.6 µg/mL), myricetin (500 µg/mL), 1771 + myricetin, fluoride (250 ppm), 1771 + fluoride, myricetin + fluoride, 1771 + myricetin + fluoride, and vehicle. Biofilms were evaluated via microbiological, biochemical, imaging, and gene expression methods. Compound 1771 alone yielded less viable counts, biomass, exopolysaccharides, and extracellular LTA. Moreover, the combination 1771 + myricetin + fluoride decreased three logs of bacterium counts, 60% biomass, >74% exopolysaccharides, and 20% LTA. The effect of treatments on extracellular DNA was not pronounced. The combination strategy affected the size of microcolonies and exopolysaccharides distribution and inhibited the expression of genes linked to insoluble exopolysaccharides synthesis. Therefore, compound 1771 prevented the accumulation of S. mutans biofilm; however, the effect was more pronounced when it was associated with fluoride and myricetin.
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A Novel Biocompatible Titanium-Gadolinium Quantum Dot as a Bacterial Detecting Agent with High Antibacterial Activity. NANOMATERIALS 2020; 10:nano10040778. [PMID: 32316666 PMCID: PMC7221622 DOI: 10.3390/nano10040778] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/14/2020] [Accepted: 04/16/2020] [Indexed: 11/17/2022]
Abstract
In this study, the titanium–gadolinium quantum dots (TGQDs) were novel, first of its type to be synthesized, and fully characterized to date. Multiple physical characterization includes scanning electron microscopy (SEM), scanning electrochemical microscope (SCEM), x-ray fluorescence, spectrophotometry, and dynamic light scattering were carried out. The obtained results confirmed appropriate size and shape distributions in addition to processing optical features with high quantum yield. The synthesized TGQD was used as a fluorescent dye for bacterial detection and imaging by fluorescent microscopy and spectrophotometry, where TGQD stained only bacterial cells, but not human cells. The significant antibacterial activities of the TGQDs were found against a highly pathogenic bacterium (Staphylococcus aureus) and its antibiotic resistant strains (vancomycin and methicillin resistant Staphylococcus aureus) using growth curve analysis and determination of minimum inhibitory concentration (MIC) analysis. Live/dead cell imaging assay using phase-contrast microscope was performed for further confirmation of the antibacterial activity. Cell wall disruption and release of cell content was observed to be the prime mode of action with the reduction of cellular oxygen demand (OD).
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Lu K, Hou W, Xu XF, Chen Q, Li Z, Lin J, Chen WM. Biological evaluation and chemoproteomics reveal potential antibacterial targets of a cajaninstilbene-acid analogue. Eur J Med Chem 2020; 188:112026. [DOI: 10.1016/j.ejmech.2019.112026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/29/2019] [Accepted: 12/29/2019] [Indexed: 12/17/2022]
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Yuan G, Li P, Xu X, Li P, Zhong Q, He S, Yi H, Yi W, Guan Y, Wen ZT. Azalomycin F 5a Eradicates Staphylococcus aureus Biofilm by Rapidly Penetrating and Subsequently Inducing Cell Lysis. Int J Mol Sci 2020; 21:ijms21030862. [PMID: 32013221 PMCID: PMC7036916 DOI: 10.3390/ijms21030862] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/24/2020] [Accepted: 01/28/2020] [Indexed: 12/14/2022] Open
Abstract
Antimicrobial resistance has emerged as a serious threat to public health. Bacterial biofilm, as a natural lifestyle, is a major contributor to resistance to antimicrobials. Azalomycin F5a, a natural guanidine-containing polyhydroxy macrolide, has remarkable activities against Gram-positive bacteria, including Staphylococcus aureus, a major causative agent of hospital-acquired infections. To further evaluate its potential to be developed as a new antimicrobial agent, its influence on S. aureus biofilm formation was evaluated using the crystal violet method, and then its eradication effect against mature biofilms was determined by confocal laser scanning microscopy, the drop plate method, and regrowth experiments. The results showed that azalomycin F5a could significantly inhibit S. aureus biofilm formation, and such effects were concentration dependent. In addition, it can also eradicate S. aureus mature biofilms with the minimum biofilm eradication concentration of 32.0 μg/mL. As extracellular deoxyribonucleic acid (eDNA) plays important roles in the structural integrity of bacterial biofilm, its influence on the eDNA release in S. aureus biofilm was further analyzed using gel electrophoresis. Combined with our previous works, these results indicate that azalomycin F5a could rapidly penetrate biofilm and causes damages to the cell membrane, leading to an increase in DNase release and eventually eradicating S. aureus biofilm.
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Affiliation(s)
- Ganjun Yuan
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; (P.L.); (Q.Z.)
- Department of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, New Orleans, LA 70119, USA
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70119, USA
- Correspondence: (G.Y.); (Z.T.W.); Tel.: +86-791-83813459 (G.Y.); +1-504-9418465 (Z.T.W.)
| | - Pingyi Li
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; (P.L.); (Q.Z.)
| | - Xuejie Xu
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; (P.L.); (Q.Z.)
| | - Peibo Li
- School of Life Sciences, Sun Yat-sen University, 135 Xingang Road, Guangzhou 510275, China
| | - Qiwang Zhong
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; (P.L.); (Q.Z.)
| | - Su He
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; (P.L.); (Q.Z.)
| | - Houqin Yi
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; (P.L.); (Q.Z.)
| | - Wenfang Yi
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; (P.L.); (Q.Z.)
| | - Yingying Guan
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; (P.L.); (Q.Z.)
| | - Zezhang Tom Wen
- Department of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, New Orleans, LA 70119, USA
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70119, USA
- Correspondence: (G.Y.); (Z.T.W.); Tel.: +86-791-83813459 (G.Y.); +1-504-9418465 (Z.T.W.)
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Lima BP, Kho K, Nairn BL, Davies JR, Svensäter G, Chen R, Steffes A, Vreeman GW, Meredith TC, Herzberg MC. Streptococcus gordonii Type I Lipoteichoic Acid Contributes to Surface Protein Biogenesis. mSphere 2019; 4:e00814-19. [PMID: 31801844 PMCID: PMC6893214 DOI: 10.1128/msphere.00814-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 12/18/2022] Open
Abstract
Lipoteichoic acid (LTA) is an abundant polymer of the Gram-positive bacterial cell envelope and is essential for many species. Whereas the exact function of LTA has not been elucidated, loss of LTA in some species affects hydrophobicity, biofilm formation, and cell division. Using a viable LTA-deficient strain of the human oral commensal Streptococcus gordonii, we demonstrated that LTA plays an important role in surface protein presentation. Cell wall fractions derived from the wild-type and LTA-deficient strains of S. gordonii were analyzed using label-free mass spectroscopy. Comparisons showed that the abundances of many proteins differed, including (i) SspA, SspB, and S. gordonii 0707 (SGO_0707) (biofilm formation); (ii) FtsE (cell division); (iii) Pbp1a and Pbp2a (cell wall biosynthesis and remodeling); and (iv) DegP (envelope stress response). These changes in cell surface protein presentation appear to explain our observations of altered cell envelope homeostasis, biofilm formation, and adhesion to eukaryotic cells, without affecting binding and coaggregation with other bacterial species, and provide insight into the phenotypes revealed by the loss of LTA in other species of Gram-positive bacteria. We also characterized the chemical structure of the LTA expressed by S. gordonii Similarly to Streptococcus suis, S. gordonii produced a complex type I LTA, decorated with multiple d-alanylations and glycosylations. Hence, the S. gordonii LTA appears to orchestrate expression and presentation of cell surface-associated proteins and functions.IMPORTANCE Discovered over a half-century ago, lipoteichoic acid (LTA) is an abundant polymer found on the surface of Gram-positive bacteria. Although LTA is essential for the survival of many Gram-positive species, knowledge of how LTA contributes to bacterial physiology has remained elusive. Recently, LTA-deficient strains have been generated in some Gram-positive species, including the human oral commensal Streptococcus gordonii The significance of our research is that we utilized an LTA-deficient strain of S. gordonii to address why LTA is physiologically important to Gram-positive bacteria. We demonstrate that in S. gordonii, LTA plays an important role in the presentation of many cell surface-associated proteins, contributing to cell envelope homeostasis, cell-to-cell interactions in biofilms, and adhesion to eukaryotic cells. These data may broadly reflect a physiological role of LTA in Gram-positive bacteria.
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Affiliation(s)
- Bruno P Lima
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kelvin Kho
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, State College, Pennsylvania, USA
| | - Brittany L Nairn
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Julia R Davies
- Department of Oral Biology, Faculty of Odontology, Malmo University, Malmo, Sweden
| | - Gunnel Svensäter
- Department of Oral Biology, Faculty of Odontology, Malmo University, Malmo, Sweden
| | - Ruoqiong Chen
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Amanda Steffes
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Gerrit W Vreeman
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Timothy C Meredith
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, State College, Pennsylvania, USA
| | - Mark C Herzberg
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
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Guanidine-Containing Polyhydroxyl Macrolides: Chemistry, Biology, and Structure-Activity Relationship. Molecules 2019; 24:molecules24213913. [PMID: 31671653 PMCID: PMC6864768 DOI: 10.3390/molecules24213913] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 10/26/2019] [Accepted: 10/29/2019] [Indexed: 12/20/2022] Open
Abstract
Antimicrobial resistance has been seriously threatening human health, and discovering new antimicrobial agents from the natural resource is still an important pathway among various strategies to prevent resistance. Guanidine-containing polyhydroxyl macrolides, containing a polyhydroxyl lactone ring and a guanidyl side chain, can be produced by many actinomycetes and have been proved to possess many bioactivities, especially broad-spectrum antibacterial and antifungal activities. To explore the potential of these compounds to be developed into new antimicrobial agents, a review on their structural diversities, spectroscopic characterizations, bioactivities, acute toxicities, antimicrobial mechanisms, and the structure-activity relationship was first performed based on the summaries and analyses of related publications from 1959 to 2019. A total of 63 guanidine-containing polyhydroxyl macrolides were reported, including 46 prototype compounds isolated from 33 marine and terrestrial actinomycetes and 17 structural derivatives. Combining with their antimicrobial mechanisms, structure-activity relationship analyses indicated that the terminal guanidine group and lactone ring of these compounds are vital for their antibacterial and antifungal activities. Further, based on their bioactivities and toxicity analyses, the discovery of guanidyl side-chain targeting to lipoteichoic acid of Staphylococcus aureus indicated that these compounds have a great potency to be developed into antimicrobial and anti-inflammatory drugs.
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Dickson K, Lehmann C. Inflammatory Response to Different Toxins in Experimental Sepsis Models. Int J Mol Sci 2019; 20:ijms20184341. [PMID: 31491842 PMCID: PMC6770119 DOI: 10.3390/ijms20184341] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/27/2019] [Accepted: 09/02/2019] [Indexed: 12/29/2022] Open
Abstract
Sepsis is defined as life-threatening organ dysfunction caused by the dysregulated host response to infection. Despite serious mortality and morbidity, no sepsis-specific drugs exist. Endotoxemia is often used to model the hyperinflammation associated with early sepsis. This model classically uses lipopolysaccharide (LPS) from Gram-negative pathogens to activate the immune system, leading to hyperinflammation, microcirculatory disturbances and death. Other toxins may also be used to activate the immune system including Gram-positive peptidoglycan (PG) and lipoteichoic acid (LTA). In addition to these standard toxins, other bacterial components can induce inflammation. These molecules activate different signaling pathways and produce different physiological responses which can be taken advantage of for sepsis modeling. Endotoxemia modeling can provide information on pathways to inflammation in sepsis and contribute to preclinical drug development.
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Affiliation(s)
- Kayle Dickson
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
| | - Christian Lehmann
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS B3H 4R2, Canada.
- Department of Pharmacology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
- Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada.
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40
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Castillo Pedraza MC, Rosalen PL, de Castilho ARF, Freires IDA, de Sales Leite L, Faustoferri RC, Quivey RG, Klein MI. Inactivation of Streptococcus mutans genes lytST and dltAD impairs its pathogenicity in vivo. J Oral Microbiol 2019; 11:1607505. [PMID: 31143407 PMCID: PMC6522913 DOI: 10.1080/20002297.2019.1607505] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 12/19/2022] Open
Abstract
Background: Streptococcus mutans orchestrates the development of a biofilm that causes dental caries in the presence of dietary sucrose, and, in the bloodstream, S. mutans can cause systemic infections. The development of a cariogenic biofilm is dependent on the formation of an extracellular matrix rich in exopolysaccharides, which contains extracellular DNA (eDNA) and lipoteichoic acids (LTAs). While the exopolysaccharides are virulence markers, the involvement of genes linked to eDNA and LTAs metabolism in the pathogenicity of S. mutans remains unclear. Objective and Design: In this study, a parental strain S. mutans UA159 and derivative strains carrying single gene deletions were used to investigate the role of eDNA (ΔlytS and ΔlytT), LTA (ΔdltA and ΔdltD), and insoluble exopolysaccharides (ΔgtfB) in virulence in a rodent model of dental caries (rats) and a systemic infection model (Galleria mellonella larvae). Results: Fewer carious lesions were observed on smooth and sulcal surfaces of enamel and dentin of the rats infected with ∆lytS, ∆dltD, and ΔgtfB (vs. the parental strain). Moreover, strains carrying gene deletions prevented the killing of larvae (vs. the parental strain). Conclusions: Altogether, these findings indicate that inactivation of lytST and dltAD impaired S. mutans cariogenicity and virulence in vivo.
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Affiliation(s)
- Midian C Castillo Pedraza
- Department of Dental Materials and Prosthodontics, Sao Paulo State University (Unesp), School of Dentistry, Araraquara, Brazil
| | - Pedro L Rosalen
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, Brazil
| | - Aline Rogéria Freire de Castilho
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, Brazil.,Department of Pediatric Dentistry, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, Brazil
| | - Irlan de Almeida Freires
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, Brazil
| | - Luana de Sales Leite
- Department of Dental Materials and Prosthodontics, Sao Paulo State University (Unesp), School of Dentistry, Araraquara, Brazil
| | | | - Robert G Quivey
- Center for Oral Biology, University of Rochester, Rochester, NY, USA
| | - Marlise I Klein
- Department of Dental Materials and Prosthodontics, Sao Paulo State University (Unesp), School of Dentistry, Araraquara, Brazil
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41
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Naclerio GA, Karanja CW, Opoku-Temeng C, Sintim HO. Antibacterial Small Molecules That Potently Inhibit Staphylococcus aureus Lipoteichoic Acid Biosynthesis. ChemMedChem 2019; 14:1000-1004. [PMID: 30939229 DOI: 10.1002/cmdc.201900053] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/20/2019] [Indexed: 01/02/2023]
Abstract
The rise of antibiotic resistance, especially in Staphylococcus aureus, and the increasing death rate due to multiresistant bacteria have been well documented. The need for new chemical entities and/or the identification of novel targets for antibacterial drug development is high. Lipoteichoic acid (LTA), a membrane-attached anionic polymer, is important for the growth and virulence of many Gram-positive bacteria, and interest has been high in the discovery of LTA biosynthesis inhibitors. Thus far, only a handful of LTA biosynthesis inhibitors have been described with moderate (MIC=5.34 μg mL-1 ) to low (MIC=1024 μg mL-1 ) activities against S. aureus. Herein we describe the identification of novel compounds that potently inhibit LTA biosynthesis in S. aureus, displaying impressive antibacterial activities (MIC as low as 0.25 μg mL-1 ) against methicillin-resistant S. aureus (MRSA). Under similar in vitro assay conditions, these compounds are 4-fold more potent than vancomycin and 8-fold more potent than linezolid against MRSA.
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Affiliation(s)
- George A Naclerio
- Chemistry Department, Institute for Drug Discovery, Purdue University, West Lafayette, IN, 47907, USA
| | - Caroline W Karanja
- Chemistry Department, Institute for Drug Discovery, Purdue University, West Lafayette, IN, 47907, USA
| | - Clement Opoku-Temeng
- Chemistry Department, Institute for Drug Discovery, Purdue University, West Lafayette, IN, 47907, USA.,Graduate Program in Biochemistry, University of Maryland, College Park, MD, 20742, USA
| | - Herman O Sintim
- Chemistry Department, Institute for Drug Discovery, Purdue University, West Lafayette, IN, 47907, USA
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42
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Lectin-based detection of Escherichia coli and Staphylococcus aureus by flow cytometry. Arch Microbiol 2019; 201:313-324. [DOI: 10.1007/s00203-018-1613-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 11/28/2018] [Accepted: 12/20/2018] [Indexed: 01/19/2023]
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43
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Azalomycin F5a, a polyhydroxy macrolide binding to the polar head of phospholipid and targeting to lipoteichoic acid to kill methicillin-resistant Staphylococcus aureus. Biomed Pharmacother 2019; 109:1940-1950. [DOI: 10.1016/j.biopha.2018.11.067] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 11/13/2018] [Accepted: 11/19/2018] [Indexed: 11/22/2022] Open
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44
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Rakesh KP, Marichannegowda MH, Srivastava S, Chen X, Long S, Karthik CS, Mallu P, Qin HL. Combating a Master Manipulator: Staphylococcus aureus Immunomodulatory Molecules as Targets for Combinatorial Drug Discovery. ACS COMBINATORIAL SCIENCE 2018; 20:681-693. [PMID: 30372025 DOI: 10.1021/acscombsci.8b00088] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Staphylococcus aureus is a bacterial pathogen that can cause significant disease burden and mortality by counteracting host defenses through producing virulence factors to survive the immune responses evoked by infection. This emerging drug-resistant pathogen has led to a decline in the efficacy of traditional antimicrobial therapy. To combat these threats, precision antimicrobial therapeutics have been created to target key virulence determinants of specific pathogens. Here we review the benefits of, progresses in, and roadblocks to the development of precision antimicrobial therapeutics using combinatorial chemistry.
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Affiliation(s)
- Kadalipura P. Rakesh
- Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430070, Hubei, P. R. China
| | | | - Shobhith Srivastava
- Department of Pharmacology and Therapeutics, King George’s Medical University, Chowk, Lucknow 226003, India
| | - Xing Chen
- Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430070, Hubei, P. R. China
| | - Sihui Long
- Key Laboratory for Green Chemical Process of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430073, Hubei, China
| | - Chimatahalli S. Karthik
- Department of Chemistry, Sri Jayachamarajendra College of Engineering, Mysuru 570006, Karnataka, India
| | - Putswamappa Mallu
- Department of Chemistry, Sri Jayachamarajendra College of Engineering, Mysuru 570006, Karnataka, India
| | - Hua-Li Qin
- Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430070, Hubei, P. R. China
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45
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Kuenemann MA, Spears PA, Orndorff PE, Fourches D. In silicoPredicted Glucose-1-phosphate Uridylyltransferase (GalU) Inhibitors Block a Key Pathway Required forListeriaVirulence. Mol Inform 2018. [DOI: 10.1002/minf.201800004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Melaine A. Kuenemann
- Department of Chemistry, Bioinformatics Research Center; North Carolina State University; Raleigh, NC USA
| | - Patricia A. Spears
- Department of Population Health and Pathobiology, College of Veterinary Medicine; North Carolina State University; Raleigh, NC USA
| | - Paul E. Orndorff
- Department of Population Health and Pathobiology, College of Veterinary Medicine; North Carolina State University; Raleigh, NC USA
| | - Denis Fourches
- Department of Chemistry, Bioinformatics Research Center; North Carolina State University; Raleigh, NC USA
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46
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Rismondo J, Percy MG, Gründling A. Discovery of genes required for lipoteichoic acid glycosylation predicts two distinct mechanisms for wall teichoic acid glycosylation. J Biol Chem 2018; 293:3293-3306. [PMID: 29343515 PMCID: PMC5836110 DOI: 10.1074/jbc.ra117.001614] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 01/13/2018] [Indexed: 12/20/2022] Open
Abstract
The bacterial cell wall is an important and highly complex structure that is essential for bacterial growth because it protects bacteria from cell lysis and environmental insults. A typical Gram-positive bacterial cell wall is composed of peptidoglycan and the secondary cell wall polymers, wall teichoic acid (WTA) and lipoteichoic acid (LTA). In many Gram-positive bacteria, LTA is a polyglycerol-phosphate chain that is decorated with d-alanine and sugar residues. However, the function of and proteins responsible for the glycosylation of LTA are either unknown or not well-characterized. Here, using bioinformatics, genetic, and NMR spectroscopy approaches, we found that the Bacillus subtilis csbB and yfhO genes are essential for LTA glycosylation. Interestingly, the Listeria monocytogenes gene lmo1079, which encodes a YfhO homolog, was not required for LTA glycosylation, but instead was essential for WTA glycosylation. LTA is polymerized on the outside of the cell and hence can only be glycosylated extracellularly. Based on the similarity of the genes coding for YfhO homologs that are required in B. subtilis for LTA glycosylation or in L. monocytogenes for WTA glycosylation, we hypothesize that WTA glycosylation might also occur extracellularly in Listeria species. Finally, we discovered that in L. monocytogenes, lmo0626 (gtlB) was required for LTA glycosylation, indicating that the encoded protein has a function similar to that of YfhO, although the proteins are not homologous. Together, our results enable us to propose an updated model for LTA glycosylation and also indicate that glycosylation of WTA might occur through two different mechanisms in Gram-positive bacteria.
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Affiliation(s)
- Jeanine Rismondo
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Matthew G Percy
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Angelika Gründling
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
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47
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Spaulding CN, Klein RD, Schreiber HL, Janetka JW, Hultgren SJ. Precision antimicrobial therapeutics: the path of least resistance? NPJ Biofilms Microbiomes 2018; 4:4. [PMID: 29507749 PMCID: PMC5829159 DOI: 10.1038/s41522-018-0048-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 01/17/2018] [Accepted: 01/24/2018] [Indexed: 01/15/2023] Open
Abstract
The emergence of drug-resistant pathogens has led to a decline in the efficacy of traditional antimicrobial therapy. The rise in resistance has been driven by widespread use, and in some cases misuse, of antibacterial agents in treating a variety of infections. A growing body of research has begun to elucidate the harmful effects of broad-spectrum antibiotic therapy on the beneficial host microbiota. To combat these threats, increasing effort is being directed toward the development of precision antimicrobial therapeutics that target key virulence determinants of specific pathogens while leaving the remainder of the host microbiota undisturbed. This includes the recent development of small molecules termed “mannosides” that specifically target uropathogenic E. coli (UPEC). Mannosides are glycomimetics of the natural mannosylated host receptor for type 1 pili, extracellular appendages that promotes UPEC colonization in the intestine. Type 1 pili are also critical for colonization and infection in the bladder. In both cases, mannosides act as molecular decoys which potently prevent bacteria from binding to host tissues. In mice, oral treatment with mannosides simultaneously clears active bladder infection and removes intestinal UPEC while leaving the gut microbiota structure relatively unchanged. Similar treatment strategies successfully target other pathogens, like adherent-invasive E. coli (AIEC), an organism associated with Crohn’s disease (CD), in mouse models. While not without its challenges, antibiotic-sparing therapeutic approaches hold great promise in a variety of disease systems, including UTI, CD, otitis media (OM), and others. In this perspective we highlight the benefits, progress, and roadblocks to the development of precision antimicrobial therapeutics.
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Affiliation(s)
- Caitlin N Spaulding
- 1Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA 02115 USA.,2Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110 USA.,3Center for Women's Infectious Disease Research (CWIDR), Washington University School of Medicine, St. Louis, MO 63110 USA
| | - Roger D Klein
- 2Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110 USA.,3Center for Women's Infectious Disease Research (CWIDR), Washington University School of Medicine, St. Louis, MO 63110 USA
| | - Henry L Schreiber
- 2Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110 USA.,3Center for Women's Infectious Disease Research (CWIDR), Washington University School of Medicine, St. Louis, MO 63110 USA
| | - James W Janetka
- 3Center for Women's Infectious Disease Research (CWIDR), Washington University School of Medicine, St. Louis, MO 63110 USA.,4Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110 USA
| | - Scott J Hultgren
- 2Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110 USA.,3Center for Women's Infectious Disease Research (CWIDR), Washington University School of Medicine, St. Louis, MO 63110 USA
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48
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Vickery CR, Wood BM, Morris HG, Losick R, Walker S. Reconstitution of Staphylococcus aureus Lipoteichoic Acid Synthase Activity Identifies Congo Red as a Selective Inhibitor. J Am Chem Soc 2018; 140:876-879. [PMID: 29300473 PMCID: PMC5856125 DOI: 10.1021/jacs.7b11704] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Lipoteichoic acid (LTA) is an anionic surface polymer that is essential for normal growth of Staphylococcus aureus, making the LTA polymerase, LTA synthase (LtaS), a proposed drug target for combating Staphylococcal infections. LtaS is a polytopic membrane protein with five membrane-spanning helices and an extracellular domain, and it uses phosphatidylglycerol to assemble a glycerol phosphate chain on a glycosylated diacylglycerol membrane anchor. We report here the first reconstitution of LtaS polymerization activity and show that the azo dye Congo red inhibits this enzyme both in vitro and in cells. Related azo dyes and the previously reported LtaS inhibitor 1771 have weak or no in vitro inhibitory activity. Synthetic lethality with mutant strains known to be nonviable in the absence of LTA confirms selective inhibition by Congo red. As the only validated LtaS inhibitor, Congo red can serve as a probe to understand how inhibiting lipoteichoic acid biosynthesis affects cell physiology and may also guide the discovery of more potent inhibitors for use in treating S. aureus infections.
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Affiliation(s)
- Christopher R. Vickery
- Department of Microbiology and Immunobiology, Harvard University, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - B. McKay Wood
- Department of Microbiology and Immunobiology, Harvard University, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Heidi G. Morris
- Department of Microbiology and Immunobiology, Harvard University, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Richard Losick
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Suzanne Walker
- Department of Microbiology and Immunobiology, Harvard University, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
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49
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Foster TJ. Antibiotic resistance in Staphylococcus aureus. Current status and future prospects. FEMS Microbiol Rev 2018; 41:430-449. [PMID: 28419231 DOI: 10.1093/femsre/fux007] [Citation(s) in RCA: 391] [Impact Index Per Article: 65.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/12/2017] [Indexed: 12/11/2022] Open
Abstract
The major targets for antibiotics in staphylococci are (i) the cell envelope, (ii) the ribosome and (iii) nucleic acids. Several novel targets emerged from recent targeted drug discovery programmes including the ClpP protease and FtsZ from the cell division machinery. Resistance can either develop by horizontal transfer of resistance determinants encoded by mobile genetic elements viz plasmids, transposons and the staphylococcal cassette chromosome or by mutations in chromosomal genes. Horizontally acquired resistance can occur by one of the following mechanisms: (i) enzymatic drug modification and inactivation, (ii) enzymatic modification of the drug binding site, (iii) drug efflux, (iv) bypass mechanisms involving acquisition of a novel drug-resistant target, (v) displacement of the drug to protect the target. Acquisition of resistance by mutation can result from (i) alteration of the drug target that prevents the inhibitor from binding, (ii) derepression of chromosomally encoded multidrug resistance efflux pumps and (iii) multiple stepwise mutations that alter the structure and composition of the cell wall and/or membrane to reduce drug access to its target. This review focuses on development of resistance to currently used antibiotics and examines future prospects for new antibiotics and informed use of drug combinations.
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50
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Chilambi GS, Gao IH, Yoon BK, Park S, Kawakami LM, Ravikumar V, Chan-Park MB, Cho NJ, Bazan GC, Kline KA, Rice SA, Hinks J. Membrane adaptation limitations inEnterococcus faecalisunderlie sensitivity and the inability to develop significant resistance to conjugated oligoelectrolytes. RSC Adv 2018; 8:10284-10293. [PMID: 35540442 PMCID: PMC9078823 DOI: 10.1039/c7ra11823f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 03/01/2018] [Indexed: 11/21/2022] Open
Abstract
COEs are emerging antimicrobials to combat drug resistant infections and to which bacteria develop only limited resistance.
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