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Mitra A, Naik L, Dhiman R, Sarkar N. Protonation-State Dependent Modulation of Hen Egg-White Lysozyme Fibrillation under the Influence of a Short Synthetic Peptide. J Phys Chem B 2024; 128:5995-6013. [PMID: 38875472 DOI: 10.1021/acs.jpcb.4c01578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2024]
Abstract
Under the influence of various conditions, misfolding of soluble proteins occurs, leading to the formation of toxic insoluble amyloids. The formation and deposition of such amyloids within the body are associated with detrimental biological consequences such as the onset of several amyloid-related diseases. Previously, we established a strategy for the rational design of peptide inhibitors against amyloid formation based on the amyloidogenic-prone region of the protein. In the current study, we have designed and identified an Asp-containing rationally designed hexapeptide (SqP4) as an excellent inhibitor of hen egg-white lysozyme (HEWL) amyloid progression in vitro. First, SqP4 showed strong affinity toward the native monomeric HEWL leading to the stabilization of the native form and restriction in the unfolding process of monomeric HEWL. Second, SqP4 was found to arrest the amyloidogenic misfolded structure of HEWL in a nonfibrillar monomer-like stage. We also observed the differential effect of the protonation state of the charged amino acid (Asp) within the peptide inhibitor on the amyloid formation of HEWL and explored the reason behind the observations. The findings of this study can be implemented in future strategies for the development of potent therapeutics against other amyloid-related diseases.
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Affiliation(s)
- Amit Mitra
- Department of Biotechnology and Medical Engineering, National Institute of Technology Rourkela, Rourkela 769008, Odisha, India
| | - Lincoln Naik
- Laboratory of Mycobacterial Immunology, Department of Life Science, National Institute of Technology Rourkela, Rourkela 769008, Odisha, India
| | - Rohan Dhiman
- Laboratory of Mycobacterial Immunology, Department of Life Science, National Institute of Technology Rourkela, Rourkela 769008, Odisha, India
| | - Nandini Sarkar
- Department of Biotechnology and Medical Engineering, National Institute of Technology Rourkela, Rourkela 769008, Odisha, India
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2
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Sharma P, Vaiwala R, Gopinath AK, Chockalingam R, Ayappa KG. Structure of the Bacterial Cell Envelope and Interactions with Antimicrobials: Insights from Molecular Dynamics Simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:7791-7811. [PMID: 38451026 DOI: 10.1021/acs.langmuir.3c03474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
Bacteria have evolved over 3 billion years, shaping our intrinsic and symbiotic coexistence with these single-celled organisms. With rising populations of drug-resistant strains, the search for novel antimicrobials is an ongoing area of research. Advances in high-performance computing platforms have led to a variety of molecular dynamics simulation strategies to study the interactions of antimicrobial molecules with different compartments of the bacterial cell envelope of both Gram-positive and Gram-negative species. In this review, we begin with a detailed description of the structural aspects of the bacterial cell envelope. Simulations concerned with the transport and associated free energy of small molecules and ions through the outer membrane, peptidoglycan, inner membrane and outer membrane porins are discussed. Since surfactants are widely used as antimicrobials, a section is devoted to the interactions of surfactants with the cell wall and inner membranes. The review ends with a discussion on antimicrobial peptides and the insights gained from the molecular simulations on the free energy of translocation. Challenges involved in developing accurate molecular models and coarse-grained strategies that provide a trade-off between atomic details with a gain in sampling time are highlighted. The need for efficient sampling strategies to obtain accurate free energies of translocation is also discussed. Molecular dynamics simulations have evolved as a powerful tool that can potentially be used to design and develop novel antimicrobials and strategies to effectively treat bacterial infections.
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Affiliation(s)
- Pradyumn Sharma
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
| | - Rakesh Vaiwala
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
| | - Amar Krishna Gopinath
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
| | - Rajalakshmi Chockalingam
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
| | - K Ganapathy Ayappa
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
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3
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Sangklai N, Supungul P, Jaroenlak P, Tassanakajon A. Immune signaling of Litopenaeus vannamei c-type lysozyme and its role during microsporidian Enterocytozoon hepatopenaei (EHP) infection. PLoS Pathog 2024; 20:e1012199. [PMID: 38683868 PMCID: PMC11081493 DOI: 10.1371/journal.ppat.1012199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 05/09/2024] [Accepted: 04/16/2024] [Indexed: 05/02/2024] Open
Abstract
The microsporidian Enterocytozoon hepatopenaei (EHP) is a fungi-related, spore-forming parasite. EHP infection causes growth retardation and size variation in shrimp, resulting in severe economic losses. Studies on shrimp immune response have shown that several antimicrobial peptides (AMPs) were upregulated upon EHP infection. Among those highly upregulated AMPs is c-type lysozyme (LvLyz-c). However, the immune signaling pathway responsible for LvLyz-c production in shrimp as well as its function against the EHP infection are still poorly understood. Here, we characterized major shrimp immune signaling pathways and found that Toll and JAK/STAT pathways were up-regulated upon EHP infection. Knocking down of a Domeless (DOME) receptor in the JAK/STAT pathways resulted in a significant reduction of the LvLyz-c and the elevation of EHP copy number. We further elucidated the function of LvLyz-c by heterologously expressing a recombinant LvLyz-c (rLvLyz-c) in an Escherichia coli. rLvLyz-c exhibited antibacterial activity against several bacteria such as Bacillus subtilis and Vibrio parahaemolyticus. Interestingly, we found an antifungal activity of rLvLyz-c against Candida albican, which led us to further investigate the effects of rLvLyz-c on EHP spores. Incubation of the EHP spores with rLvLyz-c followed by a chitin staining showed that the signals were dramatically decreased in a dose-dependent manner, suggesting that rLvLyz-c possibly digest a chitin coat on the EHP spores. Transmission electron microscopy analysis revealed that an endospore layer, which is composed mainly of chitin, was digested by rLvLyz-c. Lastly, we observed that EHP spores that were treated with rLvLyz-c showed a significant reduction of the spore germination rate. We hypothesize that thinning of the endospore of EHP would result in altered permeability, hence affecting spore germination. This work provides insights into shrimp immune signaling pathways responsible for LvLyz-c production and its anti-EHP property. This knowledge will serve as important foundations for developing EHP control strategies.
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Affiliation(s)
- Nutthapon Sangklai
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Premruethai Supungul
- Aquatic Molecular Genetics and Biotechnology Research Team, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, Thailand
| | - Pattana Jaroenlak
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Anchalee Tassanakajon
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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4
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Jia Z, Liu R, Chang Q, Zhou X, De X, Yang Z, Li Y, Zhang C, Wang F, Ge J. Proof of concept in utilizing the peptidoglycan skeleton of pathogenic bacteria as antigen delivery platform for enhanced immune response. Int J Biol Macromol 2024; 264:130591. [PMID: 38437938 DOI: 10.1016/j.ijbiomac.2024.130591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 02/29/2024] [Accepted: 03/01/2024] [Indexed: 03/06/2024]
Abstract
Subunit vaccines are becoming increasingly important because of their safety and effectiveness. However, subunit vaccines often exhibit limited immunogenicity, necessitating the use of suitable adjuvants to elicit robust immune responses. In this study, we demonstrated for the first time that pathogenic bacteria can be prepared into a purified peptidoglycan skeleton without nucleic acids and proteins, presenting bacterium-like particles (pBLP). Our results showed that the peptidoglycan skeletons screened from four pathogens could activate Toll-like receptor1/2 receptors better than bacterium-like particles from Lactococcus lactis in macrophages. We observed that pBLP was safe in mouse models of multiple ages. Furthermore, pBLP improved the performance of two commercial vaccines in vivo. We confirmed that pBLP successfully loaded antigens onto the surface and proved to be an effective antigen delivery platform with enhanced antibody titers, antibody avidity, balanced subclass distribution, and mucosal immunity. These results indicate that the peptidoglycan skeleton of pathogenic bacteria represents a new strategy for developing subunit vaccine delivery systems.
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Affiliation(s)
- Zheng Jia
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150036, China
| | - Runhang Liu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150036, China; State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150086, China
| | - Qingru Chang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150036, China
| | - Xinyao Zhou
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150036, China
| | - Xinqi De
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150036, China
| | - Zaixing Yang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150036, China
| | - Yifan Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150036, China
| | - Chuankun Zhang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150036, China
| | - Fang Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150086, China.
| | - Junwei Ge
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150036, China; Heilongjiang Provincial Key Laboratory of Zoonosis, Harbin 150036, China.
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5
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Zhang T, Wu Z, Ng G, Boyer C. Design of an Oxygen-Tolerant Photo-RAFT System for Protein-Polymer Conjugation Achieving High Bioactivity. Angew Chem Int Ed Engl 2023; 62:e202309582. [PMID: 37591792 DOI: 10.1002/anie.202309582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 08/15/2023] [Accepted: 08/17/2023] [Indexed: 08/19/2023]
Abstract
Protein-polymer conjugates have significant potential in pharmaceutical and biomedical applications. To enable their widespread use, robust conjugation techniques are crucial. This study introduces a photo-initiated reversible addition-fragmentation chain-transfer (Photo-RAFT) polymerization system that exhibits excellent oxygen tolerance. This system allows for the synthesis of protein-polymer conjugates with high bioactivity under mild and aerobic conditions. Three photocatalytic systems utilizing Eosin Y (EY) as the photocatalyst with two different cocatalysts (ascorbic acid and triethanolamine) were investigated, each generating distinct reactive oxygen species (ROS) such as singlet oxygen, superoxide, hydrogen peroxide, and hydroxyl radicals. The impact of these ROS on three model proteins (lysozyme, albumin, and myoglobin) was evaluated, demonstrating varying bioactivities based on the ROS produced. The EY/TEOA system was identified as the optimal photo-RAFT initiating system, enabling the preparation of protein-polymer conjugates under aerobic conditions while maintaining high protein enzymatic activity. To showcase the potential of this approach, lysozyme-poly(dimethylaminoethyl acrylate) conjugates were successfully prepared and exhibited enhanced antimicrobial property against Gram-positive and Gram-negative bacteria.
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Affiliation(s)
- Tong Zhang
- Cluster for Advanced Macromolecular Design and UNSW RNA Institute, School of Chemical Engineering, The University of New South Wales, 2052, Sydney, NSW, Australia
| | - Zilong Wu
- Cluster for Advanced Macromolecular Design and UNSW RNA Institute, School of Chemical Engineering, The University of New South Wales, 2052, Sydney, NSW, Australia
| | - Gervase Ng
- Cluster for Advanced Macromolecular Design and UNSW RNA Institute, School of Chemical Engineering, The University of New South Wales, 2052, Sydney, NSW, Australia
| | - Cyrille Boyer
- Cluster for Advanced Macromolecular Design and UNSW RNA Institute, School of Chemical Engineering, The University of New South Wales, 2052, Sydney, NSW, Australia
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6
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Tomczyk Ł, Leśnierowski G, Cegielska-Radziejewska R. Lysozyme Modification Using Proteolytic Enzymes. Molecules 2023; 28:6260. [PMID: 37687089 PMCID: PMC10488540 DOI: 10.3390/molecules28176260] [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: 07/16/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 09/10/2023] Open
Abstract
The lysozyme in the chicken egg white consists of various bioactive amino acids. However, these compounds are inactive when they are in the sequence of parent proteins. They become active only when isolated from these proteins. The aim of this study was to modify lysozyme with proteolytic enzymes under specific conditions of the reaction environment so as to obtain active biopeptides. The physicochemical properties of the resulting preparations were also assessed. Our study showed that the modification of lysozyme with hydrolytic enzymes (pepsin and trypsin) under strictly specified conditions resulted in obtaining biopeptide preparations with new and valuable properties, as compared with native lysozyme. After the enzymatic modification of lysozyme, two structural fractions were distinguished in the composition of the resulting preparations-the monomeric fraction and the peptide fraction. The modified lysozyme exhibited high surface hydrophobicity and high total antibacterial activity despite the decrease in the hydrolytic activity. Modification of lysozyme with hydrolytic enzymes, especially pepsin, resulted in preparations with very good antioxidative properties.
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Affiliation(s)
- Łukasz Tomczyk
- Department of Food Quality and Safety Management, Poznan University of Life Sciences, 60-624 Poznan, Poland; (G.L.); (R.C.-R.)
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7
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Rani K, Pippal B, Singh SK, Karmakar A, Vankayala R, Jain N. Effects of the aspect ratio of plasmonic gold nanorods on the inhibition of lysozyme amyloid formation. Biomater Sci 2023. [PMID: 37161699 DOI: 10.1039/d3bm00400g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Amyloid formation due to altered protein folding and aggregation has gained significant attention due to its association with neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and systemic lysozyme amyloidosis. Amyloids are characterized by parallel and anti-parallel cross-β-strands arranged to form stacks of sheets that provide stability and rigidity to the amyloid core. The prototypic protein Hen Egg White Lysozyme (HEWL) has been extensively used to understand protein hydrolysis, fragmentation, folding, misfolding, and amyloid formation. In the present study, we have examined the efficacy of plasmonic gold nanorods (GNRs) as an anti-amyloid agent against HEWL amyloids. Our results reveal that (i) the amyloid inhibition by plasmonic GNRs is dependent on their aspect ratio, (ii) the large aspect ratio GNRs ameliorate amyloid assembly completely, and (iii) GNRs interfere at several stages along the lysozyme fibril-formation pathway and block the conversion of monomeric and oligomeric intermediates into mature fibrils. Using a multi-parametric approach, we demonstrate that GNRs drive HEWL into off-pathway and amyloid-incompetent forms. To establish GNRs as generic amyloid inhibitors, we extended our studies to another archetypal protein, Bovine Serum Albumin (BSA), and observed similar results of GNRs inhibiting BSA aggregation. We believe that our results will pave the way for the potential use of GNRs with current therapeutics to reduce the burden of amyloid-related diseases.
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Affiliation(s)
- Khushboo Rani
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Karwar 342030, India.
| | - Bhumika Pippal
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Karwar 342030, India.
| | - Shubham Kumar Singh
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Karwar 342030, India.
| | - Anurupa Karmakar
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Karwar 342030, India.
| | - Raviraj Vankayala
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Karwar 342030, India.
- Interdisciplinary Research Platform Smart Healthcare, Indian Institute of Technology Jodhpur, Karwar 342030, India
| | - Neha Jain
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Karwar 342030, India.
- Centre for Emerging Technologies for Sustainable Development (CETSD), Indian Institute of Technology Jodhpur, Karwar 342030, India
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8
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Li H, Pan Y, Lan Y, Yang Z, Rao J, Chen B. Molecular interaction mechanism and structure–activity relationships of protein–polyphenol complexes revealed by side-directed spin labeling-electron paramagnetic resonance (SDSL-EPR) spectroscopy. Food Chem 2023; 402:134354. [DOI: 10.1016/j.foodchem.2022.134354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 09/05/2022] [Accepted: 09/18/2022] [Indexed: 11/26/2022]
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9
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Differentiating interactions of antimicrobials with Gram-negative and Gram-positive bacterial cell walls using molecular dynamics simulations. Biointerphases 2022; 17:061008. [PMID: 36511523 DOI: 10.1116/6.0002087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Developing molecular models to capture the complex physicochemical architecture of the bacterial cell wall and to study the interaction with antibacterial molecules is an important aspect of assessing and developing novel antimicrobial molecules. We carried out molecular dynamics simulations using an atomistic model of peptidoglycan to represent the architecture for Gram-positive S. aureus. The model is developed to capture various structural features of the Staphylococcal cell wall, such as the peptide orientation, area per disaccharide, glycan length distribution, cross-linking, and pore size. A comparison of the cell wall density and electrostatic potentials is made with a previously developed cell wall model of Gram-negative bacteria, E. coli, and properties for both single and multilayered structures of the Staphylococcal cell wall are studied. We investigated the interactions of the antimicrobial peptide melittin with peptidoglycan structures. The depth of melittin binding to peptidoglycan is more pronounced in E. coli than in S. aureus, and consequently, melittin has greater contacts with glycan units of E. coli. Contacts of melittin with the amino acids of peptidoglycan are comparable across both the strains, and the D-Ala residues, which are sites for transpeptidation, show enhanced interactions with melittin. A low energetic barrier is observed for translocation of a naturally occurring antimicrobial thymol with the four-layered peptidoglycan model. The molecular model developed for Gram-positive peptidoglycan allows us to compare and contrast the cell wall penetrating properties with Gram-negative strains and assess for the first time binding and translocation of antimicrobial molecules for Gram-positive cell walls.
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10
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Lysozyme and Its Application as Antibacterial Agent in Food Industry. Molecules 2022; 27:molecules27196305. [PMID: 36234848 PMCID: PMC9572377 DOI: 10.3390/molecules27196305] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/18/2022] [Accepted: 09/21/2022] [Indexed: 11/17/2022] Open
Abstract
Lysozymes are hydrolytic enzymes characterized by their ability to cleave the β-(1,4)-glycosidic bonds in peptidoglycan, a major structural component of the bacterial cell wall. This hydrolysis action compromises the integrity of the cell wall, causing the lysis of bacteria. For more than 80 years, its role of antibacterial defense in animals has been renowned, and it is also used as a preservative in foods and pharmaceuticals. In order to improve the antimicrobial efficacy of lysozyme, extensive research has been intended for its modifications. This manuscript reviews the natural antibiotic compound lysozyme with reference to its catalytic and non-catalytic mode of antibacterial action, lysozyme types, susceptibility and resistance of bacteria, modification of lysozyme molecules, and its applications in the food industry.
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11
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Shariff M, Chatterjee M, Morris SD, Paul V, Anil Kumar V, Mohan CG, Paul-Prasanth B, Biswas R. Enhanced inhibition of Pseudomonas aeruginosa virulence factor production and biofilm development by sublethal concentrations of eugenol and phenyllactic acid. Lett Appl Microbiol 2022; 75:1336-1345. [PMID: 35962588 DOI: 10.1111/lam.13803] [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: 06/08/2022] [Revised: 08/01/2022] [Accepted: 08/05/2022] [Indexed: 11/28/2022]
Abstract
Biofilm development in P. aeruginosa is regulated by its quorum sensing (QS) systems. It has three major QS systems: LasI/R, RhlI/R, and PQS/MvfR. Previous studies showed that phenyllactic acid (PLA) binds to RhlR and PqsR and inhibits the Rhl and PQS QS; and eugenol at sublethal concentration inhibits Las and PQS QS systems. Here, we have demonstrated that a combination of sublethal doses of eugenol and PLA enhanced the inhibition of the QS mediated production of the virulence factors and biofilm development of this pathogen. A combination of 50 μM eugenol and 0.3 mM PLA significantly inhibited the pyocyanin production, protease activity, swarming motility and cytotoxic activities of P. aeruginosa strain PAO1, whereas eugenol and PLA when added individually to PAO1 cultures were less effective in inhibiting its virulence factor expression. Biofilm formation of PAO1 was reduced by 32, 19 and 87% on glass surfaces; and 54%, 49% and 93% on catheter surfaces when treated using 50 μM eugenol or 0.3 mM PLA and their combinations, respectively. The in vitro finding in the reduction of biofilm development was further validated in vivo using a catheter associated medaka fish biofilm model. Our results indicate that a combination of QS inhibitors targeting different QS pathways should be selected while designing therapeutic molecules to achieve maximum QS mediated biofilm inhibition and clinical outcome against P. aeruginosa.
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Affiliation(s)
- Mohammad Shariff
- Centre for Nanosciences and Molecular medicine, Amrita Vishwa Vidyapeetham, AIMS - Ponekkara, Cochin, Kerala, 682041, India
| | - Maitrayee Chatterjee
- Centre for Nanosciences and Molecular medicine, Amrita Vishwa Vidyapeetham, AIMS - Ponekkara, Cochin, Kerala, 682041, India
| | - Sharon D Morris
- Centre for Nanosciences and Molecular medicine, Amrita Vishwa Vidyapeetham, AIMS - Ponekkara, Cochin, Kerala, 682041, India
| | - Vinod Paul
- Centre for Nanosciences and Molecular medicine, Amrita Vishwa Vidyapeetham, AIMS - Ponekkara, Cochin, Kerala, 682041, India
| | - V Anil Kumar
- Centre for Nanosciences and Molecular medicine, Amrita Vishwa Vidyapeetham, AIMS - Ponekkara, Cochin, Kerala, 682041, India
| | - C Gopi Mohan
- Centre for Nanosciences and Molecular medicine, Amrita Vishwa Vidyapeetham, AIMS - Ponekkara, Cochin, Kerala, 682041, India
| | - Bindhu Paul-Prasanth
- Centre for Nanosciences and Molecular medicine, Amrita Vishwa Vidyapeetham, AIMS - Ponekkara, Cochin, Kerala, 682041, India
| | - Raja Biswas
- Centre for Nanosciences and Molecular medicine, Amrita Vishwa Vidyapeetham, AIMS - Ponekkara, Cochin, Kerala, 682041, India
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12
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Bray AS, Smith RD, Hudson AW, Hernandez GE, Young TM, George HE, Ernst RK, Zafar MA. MgrB-Dependent Colistin Resistance in Klebsiella pneumoniae Is Associated with an Increase in Host-to-Host Transmission. mBio 2022; 13:e0359521. [PMID: 35311534 PMCID: PMC9040857 DOI: 10.1128/mbio.03595-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 02/08/2022] [Indexed: 12/22/2022] Open
Abstract
Due to its high transmissibility, Klebsiella pneumoniae is one of the leading causes of nosocomial infections. Here, we studied the biological cost of colistin resistance, an antibiotic of last resort, in this opportunistic pathogen using a murine model of gut colonization and transmission. Colistin resistance in K. pneumoniae is commonly the result of the inactivation of the small regulatory protein MgrB. Without a functional MgrB, the two-component system PhoPQ is constitutively active, leading to an increase in lipid A modifications and subsequent colistin resistance. Using an isogenic mgrB deletion mutant (MgrB-), we demonstrate that the mutant's colistin resistance is not associated with a fitness defect under in vitro growth conditions. However, in our murine model of K. pneumoniae gastrointestinal (GI) colonization, the MgrB- colonizes the gut poorly, allowing us to identify a fitness cost. Moreover, the MgrB- mutant has higher survival outside the host compared with the parental strain. We attribute this enhanced survivability to dysregulation of the PhoPQ two-component system and accumulation of the master stress regulator RpoS. The enhanced survival of MgrB- may be critical for its rapid host-to-host transmission observed in our model. Together, our data using multiple clinical isolates demonstrate that MgrB-dependent colistin resistance in K. pneumoniae comes with a biological cost in gut colonization. However, this cost is mitigated by enhanced survival outside the host and consequently increases its host-to-host transmission. Additionally, it underscores the importance of considering the entire life cycle of a pathogen to determine the actual biological cost associated with antibiotic resistance. IMPORTANCE The biological cost associated with colistin resistance in Klebsiella pneumoniae was examined using a murine model of K. pneumoniae gut colonization and fecal-oral transmission. A common mutation resulting in colistin resistance in K. pneumoniae is a loss-of-function mutation of the small regulatory protein MgrB that regulates the two-component system PhoPQ. Even though colistin resistance in K. pneumoniae comes with a fitness defect in gut colonization, it increases bacterial survival outside the host enabling it to transmit more effectively to a new host. The enhanced survival is dependent upon the accumulation of RpoS and dysregulation of the PhoPQ. Hence, our study expands our understanding of the underlying molecular mechanism contributing to the transmission of colistin-resistant K. pneumoniae.
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Affiliation(s)
- Andrew S. Bray
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston Salem, North Carolina, USA
| | - Richard D. Smith
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, Maryland, USA
- Department of Pathology, University of Maryland, Baltimore, Baltimore, Maryland, USA
| | - Andrew W. Hudson
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston Salem, North Carolina, USA
| | - Giovanna E. Hernandez
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston Salem, North Carolina, USA
| | - Taylor M. Young
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston Salem, North Carolina, USA
| | | | - Robert K. Ernst
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, Maryland, USA
| | - M. Ammar Zafar
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston Salem, North Carolina, USA
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13
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The Influence of Antibiotic Resistance on Innate Immune Responses to Staphylococcus aureus Infection. Antibiotics (Basel) 2022; 11:antibiotics11050542. [PMID: 35625186 PMCID: PMC9138074 DOI: 10.3390/antibiotics11050542] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/13/2022] [Accepted: 04/18/2022] [Indexed: 11/16/2022] Open
Abstract
Staphylococcus aureus (S. aureus) causes a broad range of infections and is associated with significant morbidity and mortality. S. aureus produces a diverse range of cellular and extracellular factors responsible for its invasiveness and ability to resist immune attack. In recent years, increasing resistance to last-line anti-staphylococcal antibiotics daptomycin and vancomycin has been observed. Resistant strains of S. aureus are highly efficient in invading a variety of professional and nonprofessional phagocytes and are able to survive inside host cells. Eliciting immune protection against antibiotic-resistant S. aureus infection is a global challenge, requiring both innate and adaptive immune effector mechanisms. Dendritic cells (DC), which sit at the interface between innate and adaptive immune responses, are central to the induction of immune protection against S. aureus. However, it has been observed that S. aureus has the capacity to develop further antibiotic resistance and acquire increased resistance to immunological recognition by the innate immune system. In this article, we review the strategies utilised by S. aureus to circumvent antibiotic and innate immune responses, especially the interaction between S. aureus and DC, focusing on how this relationship is perturbed with the development of antibiotic resistance.
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Robinson BD, Isbell CL, Melge AR, Lomas AM, Shaji CA, Mohan CG, Huang JH, Tharakan B. Doxycycline prevents blood-brain barrier dysfunction and microvascular hyperpermeability after traumatic brain injury. Sci Rep 2022; 12:5415. [PMID: 35354869 PMCID: PMC8967830 DOI: 10.1038/s41598-022-09394-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 03/09/2022] [Indexed: 11/30/2022] Open
Abstract
The main objective of this study was to determine the cellular and molecular effects of doxycycline on the blood–brain barrier (BBB) and protection against secondary injuries following traumatic brain injury (TBI). Microvascular hyperpermeability and cerebral edema resulting from BBB dysfunction after TBI leads to elevation of intracranial pressure, secondary brain ischemia, herniation, and brain death. There are currently no effective therapies to modulate the underlying pathophysiology responsible for TBI-induced BBB dysfunction and hyperpermeability. The loss of BBB integrity by the proteolytic enzyme matrix metalloproteinase-9 (MMP-9) is critical to TBI-induced BBB hyperpermeability, and doxycycline possesses anti-MMP-9 effect. In this study, the effect of doxycycline on BBB hyperpermeability was studied utilizing molecular modeling (using Glide) in silico, cell culture-based models in vitro, and a mouse model of TBI in vivo. Brain microvascular endothelial cell assays of tight junction protein immunofluorescence and barrier permeability were performed. Adult C57BL/6 mice were subjected to sham versus TBI with or without doxycycline treatment and immediate intravital microscopic analysis for evaluating BBB integrity. Postmortem mouse brain tissue was collected to measure MMP-9 enzyme activity. It was found that doxycycline binding to the MMP-9 active sites have binding affinity of −7.07 kcal/mol. Doxycycline treated cell monolayers were protected from microvascular hyperpermeability and retained tight junction integrity (p < 0.05). Doxycycline treatment decreased BBB hyperpermeability following TBI in mice by 25% (p < 0.05). MMP-9 enzyme activity in brain tissue decreased with doxycycline treatment following TBI (p < 0.05). Doxycycline preserves BBB tight junction integrity following TBI via inhibiting MMP-9 activity. When established in human subjects, doxycycline, may provide readily accessible medical treatment after TBI to attenuate secondary injury.
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Affiliation(s)
- Bobby D Robinson
- Department of Surgery, Baylor Scott and White Medical Center, Baylor Scott and White Research Institute, Temple, TX, USA.,Texas A&M University Health Science Center College of Medicine, Temple, TX, USA
| | - Claire L Isbell
- Department of Surgery, Baylor Scott and White Medical Center, Baylor Scott and White Research Institute, Temple, TX, USA.,Texas A&M University Health Science Center College of Medicine, Temple, TX, USA
| | - Anu R Melge
- Amrita Center for Nanosciences and Molecular Medicine, Kochi, Kerala, India
| | - Angela M Lomas
- Department of Surgery, Baylor Scott and White Medical Center, Baylor Scott and White Research Institute, Temple, TX, USA.,Texas A&M University Health Science Center College of Medicine, Temple, TX, USA
| | - Chinchusha Anasooya Shaji
- Department of Surgery, Baylor Scott and White Medical Center, Baylor Scott and White Research Institute, Temple, TX, USA
| | - C Gopi Mohan
- Amrita Center for Nanosciences and Molecular Medicine, Kochi, Kerala, India
| | - Jason H Huang
- Department of Neurosurgery, Texas A&M University Health Science Center College of Medicine, Temple, TX, USA
| | - Binu Tharakan
- Department of Surgery, Baylor Scott and White Medical Center, Baylor Scott and White Research Institute, Temple, TX, USA. .,Texas A&M University Health Science Center College of Medicine, Temple, TX, USA. .,Department of Surgery, Morehouse School of Medicine, 720 Westview Dr, Atlanta, GA, 30310, USA.
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15
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Mechanism of Staphylococcus aureus peptidoglycan O-acetyltransferase A as an O-acyltransferase. Proc Natl Acad Sci U S A 2021; 118:2103602118. [PMID: 34480000 DOI: 10.1073/pnas.2103602118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 07/23/2021] [Indexed: 01/05/2023] Open
Abstract
The O-acetylation of exopolysaccharides, including the essential bacterial cell wall polymer peptidoglycan, confers resistance to their lysis by exogenous hydrolases. Like the enzymes catalyzing the O-acetylation of exopolysaccharides in the Golgi of animals and fungi, peptidoglycan O-acetyltransferase A (OatA) is predicted to be an integral membrane protein comprised of a membrane-spanning acyltransferase-3 (AT-3) domain and an extracytoplasmic domain; for OatA, these domains are located in the N- and C-terminal regions of the enzyme, respectively. The recombinant C-terminal domain (OatAC) has been characterized as an SGNH acetyltransferase, but nothing was known about the function of the N-terminal AT-3 domain (OatAN) or its homologs associated with other acyltransferases. We report herein the experimental determination of the topology of Staphylococcus aureus OatAN, which differs markedly from that predicted in silico. We present the biochemical characterization of OatAN as part of recombinant OatA and demonstrate that acetyl-CoA serves as the substrate for OatAN Using in situ and in vitro assays, we characterized 35 engineered OatA variants which identified a catalytic triad of Tyr-His-Glu residues. We trapped an acetyl group from acetyl-CoA on the catalytic Tyr residue that is located on an extracytoplasmic loop of OatAN Further enzymatic characterization revealed that O-acetyl-Tyr represents the substrate for OatAC We propose a model for OatA action involving the translocation of acetyl groups from acetyl-CoA across the cytoplasmic membrane by OatAN and their subsequent intramolecular transfer to OatAC for the O-acetylation of peptidoglycan via the concerted action of catalytic Tyr and Ser residues.
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Pushkaran AC, Nath En P, Melge AR, Puthiyedath R, Mohan CG. A phytochemical-based medication search for the SARS-CoV-2 infection by molecular docking models towards spike glycoproteins and main proteases. RSC Adv 2021; 11:12003-12014. [PMID: 35423778 PMCID: PMC8696622 DOI: 10.1039/d0ra10458b] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 03/06/2021] [Indexed: 01/07/2023] Open
Abstract
Identifying best bioactive phytochemicals from different medicinal plants using molecular docking techniques demonstrates a potential pre-clinical compound discovery against SARS-CoV-2 viral infection. The in silico screening of bioactive phytochemicals with the two druggable targets of SARS-CoV-2 by simple precision/extra precision molecular docking methods was used to compute binding affinity at its active sites. phyllaemblicin and cinnamtannin class of phytocompounds showed a better binding affinity range (-9.0 to -8.0 kcal mol-1) towards both these SARS-CoV-2 targets; the corresponding active site residues in the spike protein were predicted as: Y453, Q496, Q498, N501, Y449, Q493, G496, T500, Y505, L455, Q493, and K417; and Mpro: Q189, H164, H163, P168, H41, L167, Q192, M165, C145, Y54, M49, and Q189. Molecular dynamics simulation further established the structural and energetic stability of protein-phytocompound complexes and their interactions with their key residues supporting the molecular docking analysis. Protein-protein docking using ZDOCK and Prodigy server predicted the binding pose and affinity (-13.8 kcal mol-1) of the spike glycoprotein towards the human ACE2 enzyme and also showed significant structural variations in the ACE2 recognition site upon the binding of phyllaemblicin C compound at their binding interface. The phyllaemblicin and cinnamtannin class of phytochemicals can be potential inhibitors of both the spike and Mpro proteins of SARS-CoV-2; furthermore, its pharmacology and clinical optimization would lead towards novel COVID-19 small-molecule therapy.
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Affiliation(s)
- Anju Choorakottayil Pushkaran
- Computational Biology and Bioinformatics Lab, Center for Nanosciences and Molecular Medicine, Amrita Vishwa Vidyapeetham Kochi 682041 Kerala India +91-484-4001234 ext. 8769
| | - Prajeesh Nath En
- Amrita School of Ayurveda, Amrita Vishwa Vidyapeetham Kollam 690525 Kerala India
| | - Anu R Melge
- Computational Biology and Bioinformatics Lab, Center for Nanosciences and Molecular Medicine, Amrita Vishwa Vidyapeetham Kochi 682041 Kerala India +91-484-4001234 ext. 8769
| | | | - C Gopi Mohan
- Computational Biology and Bioinformatics Lab, Center for Nanosciences and Molecular Medicine, Amrita Vishwa Vidyapeetham Kochi 682041 Kerala India +91-484-4001234 ext. 8769
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17
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Martínez B, Rodríguez A, Kulakauskas S, Chapot-Chartier MP. Cell wall homeostasis in lactic acid bacteria: threats and defences. FEMS Microbiol Rev 2021; 44:538-564. [PMID: 32495833 PMCID: PMC7476776 DOI: 10.1093/femsre/fuaa021] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/03/2020] [Indexed: 12/16/2022] Open
Abstract
Lactic acid bacteria (LAB) encompasses industrially relevant bacteria involved in food fermentations as well as health-promoting members of our autochthonous microbiota. In the last years, we have witnessed major progresses in the knowledge of the biology of their cell wall, the outermost macrostructure of a Gram-positive cell, which is crucial for survival. Sophisticated biochemical analyses combined with mutation strategies have been applied to unravel biosynthetic routes that sustain the inter- and intra-species cell wall diversity within LAB. Interplay with global cell metabolism has been deciphered that improved our fundamental understanding of the plasticity of the cell wall during growth. The cell wall is also decisive for the antimicrobial activity of many bacteriocins, for bacteriophage infection and for the interactions with the external environment. Therefore, genetic circuits involved in monitoring cell wall damage have been described in LAB, together with a plethora of defence mechanisms that help them to cope with external threats and adapt to harsh conditions. Since the cell wall plays a pivotal role in several technological and health-promoting traits of LAB, we anticipate that this knowledge will pave the way for the future development and extended applications of LAB.
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Affiliation(s)
- Beatriz Martínez
- DairySafe research group. Department of Technology and Biotechnology of Dairy Products. Instituto de Productos Lácteos de Asturias, IPLA-CSIC. Paseo Río Linares s/n. 33300 Villaviciosa, Spain
| | - Ana Rodríguez
- DairySafe research group. Department of Technology and Biotechnology of Dairy Products. Instituto de Productos Lácteos de Asturias, IPLA-CSIC. Paseo Río Linares s/n. 33300 Villaviciosa, Spain
| | - Saulius Kulakauskas
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
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18
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Wang H, Shen X, Zheng X, Pan Y, Zhang Q, Liu Z. Intestinal lysozyme releases Nod2 ligand(s) to promote the intestinal mucosal adjuvant activity of cholera toxin. SCIENCE CHINA-LIFE SCIENCES 2021; 64:1720-1731. [PMID: 33521852 DOI: 10.1007/s11427-020-1862-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/06/2020] [Indexed: 12/01/2022]
Abstract
Commensal bacteria boost serum IgG production in response to oral immunization with antigen and cholera toxin (CT) in a manner that depends on Nod2 (nucleotide-binding oligomerization domain-containing protein 2). In this study, we examined the role of intestinal lysozyme (Lyz1) in adjuvant activity of CT. We found that Lyz1 released Nod2 ligand(s) from bacteria. Lyz1 deficiency reduced the level of circulating Nod2 ligand in mice. Lyz1 deficiency also reduced the production of IgG and T-cellspecific cytokines after oral immunization in mice. Supplementing Lyz1-deficient mice with MDP restored IgG production. Furthermore, overexpression of Lyz1 in intestinal epithelium boosted the antigen-specific IgG response induced by CT. Collectively, our results indicate that Lyz1 plays an important role in mediating the immune regulatory effect of commensal bacteria through the release of Nod2 ligand(s).
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Affiliation(s)
- Haifang Wang
- Institute for Immunology and School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Xueying Shen
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaojiao Zheng
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ying Pan
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Qin Zhang
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhihua Liu
- Institute for Immunology and School of Medicine, Tsinghua University, Beijing, 100084, China.
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19
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Wei Z, Wu S, Xia J, Shao P, Sun P, Xiang N. Enhanced Antibacterial Activity of Hen Egg-White Lysozyme against Staphylococcus aureus and Escherichia coli due to Protein Fibrillation. Biomacromolecules 2021; 22:890-897. [PMID: 33464041 DOI: 10.1021/acs.biomac.0c01599] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Antibacterial agents with broad-spectrum antibacterial properties have always been in large demand. Lysozyme, a common and inexpensive protein, is widely used in food safety and biomedical applications for antibacterial purposes. However, many pathogens are lysozyme-resistant or insensitive. In this research, we investigated the antibacterial activities and mechanism of oligomers and amyloid fibrils formed from hen egg-white lysozyme (HEWL) against Staphylococcus aureus and Escherichia coli. The HEWL fibrils showed significantly enhanced antibacterial activity against both lysozyme-resistant S. aureus and lysozyme-insensitive E. coli. The HEWL oligomers, on the other hand, did not show an obvious improvement in antibacterial activity compared to native HEWL. Our results indicated that the fibrillation of HEWL can significantly enhance antibacterial activity against both S. aureus and E. coli. The natural and inexpensive HEWL amyloid fibrils can be potentially applied to antimicrobial food packaging, animal feed, antibiotic replacement, etc.
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Affiliation(s)
- Zhengxun Wei
- College of Food Science and Technology, Zhejiang University of Technology, Zhejiang, Hangzhou 310014, P. R. China
| | - Sihong Wu
- College of Food Science and Technology, Zhejiang University of Technology, Zhejiang, Hangzhou 310014, P. R. China
| | - Jiujie Xia
- College of Food Science and Technology, Zhejiang University of Technology, Zhejiang, Hangzhou 310014, P. R. China
| | - Ping Shao
- College of Food Science and Technology, Zhejiang University of Technology, Zhejiang, Hangzhou 310014, P. R. China.,Key Laboratory of Food Macromolecular Resources Processing Technology Research, (Zhejiang University of Technology), China National Light Industry, Hangzhou 310014, P.R. China
| | - Peilong Sun
- College of Food Science and Technology, Zhejiang University of Technology, Zhejiang, Hangzhou 310014, P. R. China.,Key Laboratory of Food Macromolecular Resources Processing Technology Research, (Zhejiang University of Technology), China National Light Industry, Hangzhou 310014, P.R. China
| | - Ning Xiang
- College of Food Science and Technology, Zhejiang University of Technology, Zhejiang, Hangzhou 310014, P. R. China.,Key Laboratory of Food Macromolecular Resources Processing Technology Research, (Zhejiang University of Technology), China National Light Industry, Hangzhou 310014, P.R. China
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20
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21
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Vachher M, Sen A, Kapila R, Nigam A. Microbial therapeutic enzymes: A promising area of biopharmaceuticals. CURRENT RESEARCH IN BIOTECHNOLOGY 2021. [DOI: 10.1016/j.crbiot.2021.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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22
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Silva NHCS, Garrido-Pascual P, Moreirinha C, Almeida A, Palomares T, Alonso-Varona A, Vilela C, Freire CSR. Multifunctional nanofibrous patches composed of nanocellulose and lysozyme nanofibers for cutaneous wound healing. Int J Biol Macromol 2020; 165:1198-1210. [PMID: 33031849 DOI: 10.1016/j.ijbiomac.2020.09.249] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/08/2020] [Accepted: 09/29/2020] [Indexed: 12/26/2022]
Abstract
Cutaneous wounds frequently require the use of patches to promote healing, nevertheless, most commercial products are fabricated with non-biodegradable synthetic substrates that pose environmental problems upon disposal. Herein, the partnership between two biobased nanofibrous polymers, namely a polysaccharide (nanofibrillated cellulose (NFC)) and a protein (lysozyme nanofibers (LNFs)), is explored to design sustainable fibrous patches with good mechanical performance and biological functionalities for wound healing applications. Two patches with different morphologies were prepared by vacuum filtration of a water-based suspension of both nanofibers and by sequential filtration of the separated suspensions (layered patch). The resultant freestanding patches exhibited high thermal stability (up to 250 °C), mechanical performance (Young's modulus ≥3.7 GPa), and UV-barrier properties. The combination of the bioactive LNFs with the mechanically robust NFC conveyed antioxidant activity (76-79% DPPH scavenging) and antimicrobial activity against Staphylococcus aureus (3.5-log CFU mL-1 reduction), which is a major benefit to prevent microbial wound infections. Moreover, these patches are biocompatible towards L929 fibroblast cells, and the in vitro wound healing assay evidenced a good migration capacity leading to an almost complete wound occlusion. Therefore, the partnership between the two naturally derived nanofibrous polymers represents a potential blueprint to engineer sustainable multifunctional patches for cutaneous wound healing.
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Affiliation(s)
- Nuno H C S Silva
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
| | - Patrícia Garrido-Pascual
- Facultad de Medicina y Enfermería, Universidad del País Vasco, B° Sarriena s/n, 48940 Leioa, Bizkaia, Spain
| | - Catarina Moreirinha
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
| | - Adelaide Almeida
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Teodoro Palomares
- Facultad de Medicina y Enfermería, Universidad del País Vasco, B° Sarriena s/n, 48940 Leioa, Bizkaia, Spain
| | - Ana Alonso-Varona
- Facultad de Medicina y Enfermería, Universidad del País Vasco, B° Sarriena s/n, 48940 Leioa, Bizkaia, Spain
| | - Carla Vilela
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
| | - Carmen S R Freire
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
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Arooj M, Shehadi I, Nassab CN, Mohamed AA. Physicochemical stability study of protein–benzoic acid complexes using molecular dynamics simulations. Amino Acids 2020; 52:1353-1362. [DOI: 10.1007/s00726-020-02897-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 09/23/2020] [Indexed: 12/16/2022]
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24
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Vaiwala R, Sharma P, Puranik M, Ayappa KG. Developing a Coarse-Grained Model for Bacterial Cell Walls: Evaluating Mechanical Properties and Free Energy Barriers. J Chem Theory Comput 2020; 16:5369-5384. [DOI: 10.1021/acs.jctc.0c00539] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Rakesh Vaiwala
- Department of Chemical Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Pradyumn Sharma
- Department of Chemical Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Mrinalini Puranik
- Unilever Research & Development, 64 Main Road, Whitefield, Bangalore 560066, India
| | - K. Ganapathy Ayappa
- Department of Chemical Engineering, Indian Institute of Science, Bangalore 560012, India
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
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25
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Jones CS, Sychantha D, Howell PL, Clarke AJ. Structural basis for the O-acetyltransferase function of the extracytoplasmic domain of OatA from Staphylococcus aureus. J Biol Chem 2020; 295:8204-8213. [PMID: 32350117 DOI: 10.1074/jbc.ra120.013108] [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: 02/18/2020] [Revised: 04/27/2020] [Indexed: 02/03/2023] Open
Abstract
Many bacteria possess enzymes that modify the essential cell-wall polymer peptidoglycan by O-acetylation. This modification occurs in numerous Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus, a common cause of human infections. O-Acetylation of peptidoglycan protects bacteria from the lytic activity of lysozyme, a mammalian innate immune enzyme, and as such is important for bacterial virulence. The O-acetylating enzyme in Gram-positive bacteria, O-acetyltransferase A (OatA), is a two-domain protein consisting of an N-terminal integral membrane domain and a C-terminal extracytoplasmic domain. Here, we present the X-ray crystal structure at 1.71 Å resolution and the biochemical characterization of the C-terminal domain of S. aureus OatA. The structure revealed that this OatA domain adopts an SGNH-hydrolase fold and possesses a canonical catalytic triad. Site-specific replacement of active-site amino acids revealed the presence of a water-coordinating aspartate residue that limits esterase activity. This residue, although conserved in staphyloccocal OatA and most other homologs, is not present in the previously characterized streptococcal OatA. These results provide insights into the mechanism of acetyl transfer in the SGNH/GDSL hydrolase family and highlight important evolutionary differences between homologous OatA enzymes. Furthermore, this study enhances our understanding of PG O-acetyltransferases, which could guide the development of novel antibacterial drugs to combat infections with multidrug-resistant bacterial pathogens.
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Affiliation(s)
- Carys S Jones
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - David Sychantha
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - P Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Anthony J Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada .,Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, Ontario, Canada
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Ahmady IM, Hameed MK, Almehdi AM, Arooj M, Workie B, Sahle-Demessie E, Han C, Mohamed AA. Green and cytocompatible carboxyl modified gold-lysozyme nanoantibacterial for combating multidrug-resistant superbugs. Biomater Sci 2020; 7:5016-5026. [PMID: 31620700 DOI: 10.1039/c9bm00935c] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The dissemination of multi-drug resistant (MDR) superbugs in hospital environments, communities and food animals and the very dynamic bacterial mutation frequency require the development of prolonged therapeutic strategies to gain mastery over antibiotic resistance. A AuNP-lysozyme nanoantibacterial was fabricated by the conjugation of AuNPs-C6H4-4-COOH with lysozyme via green reduction of aryldiazonium gold(iii) salt [HOOC-4-C6H4N[triple bond, length as m-dash]N]AuCl4. Results from molecular docking calculations aimed at revealing the binding mode of benzoic acid with the lysozyme structure clearly showed the lowest energy conformation with benzoic acid bound in the deep buried hydrophobic cavity of the protein active site through strong hydrogen bonding and hydrophobic interactions, thus validating the experimental outcomes of the current study which also exhibited the binding of -COOH functional groups in the interior of the protein structure. The superiority of the lysozyme bioconjugate against superbugs was demonstrated by the enhanced and broadened lysozyme antibacterial activities of 98-99% against extended spectrum beta lactamase (ESBL) producing Escherichia coli and imipenem-resistant Pseudomonas aeruginosa clinical isolates and a selection of Gram-negative and Gram-positive standard ATCC strains. Selective toxicity against bacteria was confirmed by the high viability of HeLa and fibroblast cell lines and the outstanding hemocompatibility at the minimum bacterial inhibitory concentrations (MICs). Turbidimetric enzyme kinetic assay showed the enhancement of the lysozyme hydrolytic activity by gold nanoparticles on the Micrococcus lysodeikticus bacterial substrate. Using gel electrophoresis, the induced cell wall breakdown was confirmed by detecting the leaked-out bacterial genomic DNA. The integrity and morphology changes of the E. coli bacteria were investigated using a scanning electron microscope after one hour of contact with the lysozyme-gold bioconjugate. The antibacterial functionalities showed little or no damage to healthy human cells and can be applied to wound dressings and medical devices.
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Affiliation(s)
- Islam M Ahmady
- Department of Applied Biology, University of Sharjah, Sharjah 27272, United Arab Emirates
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Genetic Determinants Enabling Medium-Dependent Adaptation to Nafcillin in Methicillin-Resistant Staphylococcus aureus. mSystems 2020; 5:5/2/e00828-19. [PMID: 32234776 PMCID: PMC7112963 DOI: 10.1128/msystems.00828-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial susceptibility testing standards driving clinical decision-making have centered around the use of cation-adjusted Mueller-Hinton broth (CA-MHB) as the medium with the notion of supporting bacterial growth, without consideration of recapitulating the in vivo environment. However, it is increasingly recognized that various medium conditions have tremendous influence on antimicrobial activity, which in turn may have major implications on the ability of in vitro susceptibility assays to predict antibiotic activity in vivo. To elucidate differential growth optimization and antibiotic resistance mechanisms, adaptive laboratory evolution was performed in the presence or absence of the antibiotic nafcillin with methicillin-resistant Staphylococcus aureus (MRSA) TCH1516 in either (i) CA-MHB, a traditional bacteriological nutritionally rich medium, or (ii) Roswell Park Memorial Institute (RPMI), a medium more reflective of the in vivo host environment. Medium adaptation analysis showed an increase in growth rate in RPMI, but not CA-MHB, with mutations in apt, adenine phosphoribosyltransferase, and the manganese transporter subunit, mntA, occurring reproducibly in parallel replicate evolutions. The medium-adapted strains showed no virulence attenuation. Continuous exposure of medium-adapted strains to increasing concentrations of nafcillin led to medium-specific evolutionary strategies. Key reproducibly occurring mutations were specific for nafcillin adaptation in each medium type and did not confer resistance in the other medium environment. Only the vraRST operon, a regulator of membrane- and cell wall-related genes, showed mutations in both CA-MHB- and RPMI-evolved strains. Collectively, these results demonstrate the medium-specific genetic adaptive responses of MRSA and establish adaptive laboratory evolution as a platform to study clinically relevant resistance mechanisms.IMPORTANCE The ability of pathogens such as Staphylococcus aureus to evolve resistance to antibiotics used in the treatment of infections has been an important concern in the last decades. Resistant acquisition usually translates into treatment failure and puts patients at risk of unfavorable outcomes. Furthermore, the laboratory testing of antibiotic resistance does not account for the different environment the bacteria experiences within the human body, leading to results that do not translate into the clinic. In this study, we forced methicillin-resistant S. aureus to develop nafcillin resistance in two different environments, a laboratory environment and a physiologically more relevant environment. This allowed us to identify genetic changes that led to nafcillin resistance under both conditions. We concluded that not only does the environment dictate the evolutionary strategy of S. aureus to nafcillin but also that the evolutionary strategy is specific to that given environment.
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FRET-Based Aptasensor for the Selective and Sensitive Detection of Lysozyme. SENSORS 2020; 20:s20030914. [PMID: 32050422 PMCID: PMC7038949 DOI: 10.3390/s20030914] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/03/2020] [Accepted: 02/05/2020] [Indexed: 12/12/2022]
Abstract
Lysozyme is a conserved antimicrobial enzyme and has been cited for its role in immune modulation. Increase in lysozyme concentration in body fluids is also regarded as an early warning of some diseases such as Alzheimer’s, sarcoidosis, Crohn’s disease, and breast cancer. Therefore, a method for a sensitive and selective detection of lysozyme can benefit many different areas of research. In this regard, several aptamers that are specific to lysozyme have been developed, but there is still a lack of a detection method that is sensitive, specific, and quantitative. In this work, we demonstrated a single-molecule fluorescence resonance energy transfer (smFRET)-based detection of lysozyme using an aptamer sensor (also called aptasensor) in which the binding of lysozyme triggers its conformational switch from a low-FRET to high-FRET state. Using this strategy, we demonstrated that the aptasensor is sensitive down to 2.3 picomoles (30 nM) of lysozyme with a dynamic range extending to ~2 µM and has little to no interference from similar biomolecules. The smFRET approach used here requires a dramatically small amount of aptasensor (~3000-fold less as compared to typical bulk fluorescence methods), and it is cost effective compared to enzymatic and antibody-based approaches. Additionally, the aptasensor can be readily regenerated in situ via a process called toehold mediated strand displacement (TMSD). The FRET-based aptasensing of lysozyme that we developed here could be implemented to detect other protein biomarkers by incorporating protein-specific aptamers without the need for changing fluorophore-labeled DNA strands.
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Role of the msaABCR Operon in Cell Wall Biosynthesis, Autolysis, Integrity, and Antibiotic Resistance in Staphylococcus aureus. Antimicrob Agents Chemother 2019; 63:AAC.00680-19. [PMID: 31307991 DOI: 10.1128/aac.00680-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/10/2019] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus aureus is an important human pathogen in both community and health care settings. One of the challenges with S. aureus as a pathogen is its acquisition of antibiotic resistance. Previously, we showed that deletion of the msaABCR operon reduces cell wall thickness, resulting in decreased resistance to vancomycin in vancomycin-intermediate S. aureus (VISA). In this study, we investigated the nature of the cell wall defect in the msaABCR operon mutant in the Mu50 (VISA) and USA300 LAC methicillin-resistant Staphylococcus aureus (MRSA) strains. Results showed that msaABCR mutant cells had decreased cross-linking in both strains. This defect is typically due to increased murein hydrolase activity and/or nonspecific processing of murein hydrolases mediated by increased protease activity in mutant cells. The defect was enhanced by a decrease in teichoic acid content in the msaABCR mutant. Therefore, we propose that deletion of the msaABCR operon results in decreased peptidoglycan cross-linking, leading to increased susceptibility toward cell wall-targeting antibiotics, such as β-lactams and vancomycin. Moreover, we also observed significantly downregulated transcription of early cell wall-synthesizing genes, supporting the finding that msaABCR mutant cells have decreased peptidoglycan synthesis. More specifically, the msaABCR mutant in the USA300 LAC strain (MRSA) showed significantly reduced expression of the murA gene, whereas the msaABCR mutant in the Mu50 strain (VISA) showed significantly reduced expression of glmU, murA, and murD Thus, we conclude that the msaABCR operon controls the balance between cell wall synthesis and cell wall hydrolysis, which is required for maintaining a robust cell wall and acquiring resistance to cell wall-targeting antibiotics, such as vancomycin and the β-lactams.
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Brott AS, Clarke AJ. Peptidoglycan O-Acetylation as a Virulence Factor: Its Effect on Lysozyme in the Innate Immune System. Antibiotics (Basel) 2019; 8:antibiotics8030094. [PMID: 31323733 PMCID: PMC6783866 DOI: 10.3390/antibiotics8030094] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/11/2019] [Accepted: 07/13/2019] [Indexed: 11/16/2022] Open
Abstract
The peptidoglycan sacculus of both Gram-positive and Gram-negative bacteria acts as a protective mesh and provides structural support around the entirety of the cell. The integrity of this structure is of utmost importance for cell viability and so naturally is the first target for attack by the host immune system during bacterial infection. Lysozyme, a muramidase and the first line of defense of the innate immune system, targets the peptidoglycan sacculus hydrolyzing the β-(1→4) linkage between repeating glycan units, causing lysis and the death of the invading bacterium. The O-acetylation of N-acetylmuramoyl residues within peptidoglycan precludes the productive binding of lysozyme, and in doing so renders it inactive. This modification has been shown to be an important virulence factor in pathogens such as Staphylococcus aureus and Neisseria gonorrhoeae and is currently being investigated as a novel target for anti-virulence therapies. This article reviews interactions made between peptidoglycan and the host immune system, specifically with respect to lysozyme, and how the O-acetylation of the peptidoglycan interrupts these interactions, leading to increased pathogenicity.
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Affiliation(s)
- Ashley S Brott
- Department of Molecular & Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Anthony J Clarke
- Department of Molecular & Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
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Abstract
Dating back to the 1960s, initial studies on the staphylococcal cell wall were driven by the need to clarify the mode of action of the first antibiotics and the resistance mechanisms developed by the bacteria. During the following decades, the elucidation of the biosynthetic path and primary composition of staphylococcal cell walls was propelled by advances in microbial cell biology, specifically, the introduction of high-resolution analytical techniques and molecular genetic approaches. The field of staphylococcal cell wall gradually gained its own significance as the complexity of its chemical structure and involvement in numerous cellular processes became evident, namely its versatile role in host interactions, coordination of cell division and environmental stress signaling.This chapter includes an updated description of the anatomy of staphylococcal cell walls, paying particular attention to information from the last decade, under four headings: high-resolution analysis of the Staphylococcus aureus peptidoglycan; variations in peptidoglycan composition; genetic determinants and enzymes in cell wall synthesis; and complex functions of cell walls. The latest contributions to a more precise picture of the staphylococcal cell envelope were possible due to recently developed state-of-the-art microscopy and spectroscopy techniques and to a wide combination of -omics approaches, that are allowing to obtain a more integrative view of this highly dynamic structure.
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Affiliation(s)
- Rita Sobral
- UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
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Brott AS, Jones CS, Clarke AJ. Development of a High Throughput Screen for the Identification of Inhibitors of Peptidoglycan O-Acetyltransferases, New Potential Antibacterial Targets. Antibiotics (Basel) 2019; 8:E65. [PMID: 31137799 PMCID: PMC6627197 DOI: 10.3390/antibiotics8020065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 05/22/2019] [Accepted: 05/22/2019] [Indexed: 12/02/2022] Open
Abstract
The O-acetylation of peptidoglycan occurs in many Gram-negative and most Gram-positive pathogens and this modification to the essential wall polymer controls the lytic activity of the autolysins, particularly the lytic transglycosylases, and inhibits that of the lysozymes of innate immunity systems. As such, the peptidoglycan O-acetyltransferases PatA/B and OatA are recognized as virulence factors. In this study, we present the high throughput screening of small compound libraries to identify the first known inhibitors of these enzymes. The fluorometric screening assay developed involved monitoring the respective O-acetyltransferases as esterases using 4-methylumbelliferylacetate as substrate. Pilot screens of 3921 compounds validated the usefulness of the HTS protocol. A number of potential inhibitors were identified amongst a total of 145,000 low molecular-weight compounds, some of which were common to both enzymes, while others were unique to each. After eliminating a number of false positives in secondary screens, dose response curves confirmed the apparent specificity of a benzothiazolyl-pyrazolo-pyridine as an inhibitor of Neisseria gonorrhoeae PatB, and several coumarin-based compounds as inhibitors of both this PatB and OatA from Staphylococcus aureus. The benzothiazolyl-pyrazolo-pyridine was determined to be a non-competitive inhibitor of PatB with a Ki of 126 µM. At 177 µg/mL and close to its solubility limit, this compound caused a 90% reduction in growth of N. gonorrhoeae, while growth of Escherichia coli, a bacterium that lacks PatB and, hence, does not produce O-acetylated peptidoglycan, was unaffected. These data provide preliminary proof of concept that peptidoglycan O-acetyltransferases would serve as useful antibacterial targets.
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Affiliation(s)
- Ashley S Brott
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Carys S Jones
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Anthony J Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
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Pushkaran AC, Vinod V, Vanuopadath M, Nair SS, Nair SV, Vasudevan AK, Biswas R, Mohan CG. Combination of Repurposed Drug Diosmin with Amoxicillin-Clavulanic acid Causes Synergistic Inhibition of Mycobacterial Growth. Sci Rep 2019; 9:6800. [PMID: 31043655 PMCID: PMC6494880 DOI: 10.1038/s41598-019-43201-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 04/11/2019] [Indexed: 01/08/2023] Open
Abstract
Effective therapeutic regimens for the treatment of tuberculosis (TB) are limited. They are comprised of multiple drugs that inhibit the essential cellular pathways in Mycobacterium tuberculosis (Mtb). The present study investigates an approach which enables a combination of Amoxicillin-Clavulanic acid (AMC) and a repurposed drug for its synergistic effect towards TB treatment. We identified Diosmin (DIO), by targeting the active site residues of L,D-transpeptidase (Ldt) enzymes involved in Mtb cell wall biosynthesis by using a structure-based drug design method. DIO is rapidly converted into aglycone form Diosmetin (DMT) after oral administration. Binding of DIO or DMT towards Ldt enzymes was studied using molecular docking and bioassay techniques. Combination of DIO (or DMT) and AMC exhibited higher mycobactericidal activity against Mycobacterium marinum as compared to individual drugs. Scanning electron microscopy study of M. marinum treated with AMC-DIO and AMC-DMT showed marked cellular leakage. M. marinum infected Drosophila melanogaster fly model showed an increased fly survival of ~60% upon treatment with a combination of AMC and DIO (or DMT). Finally, the enhanced in vitro antimicrobial activity of AMC-DIO was validated against Mtb H37Ra and a MDR clinical isolate. Our results demonstrate the potential for AMC and DIO (or DMT) as a synergistic combination for the treatment of TB.
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Affiliation(s)
- Anju Choorakottayil Pushkaran
- Center for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham, Ponekkara, Kochi, 682 041, Kerala, India
| | - Vivek Vinod
- Center for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham, Ponekkara, Kochi, 682 041, Kerala, India
| | | | | | - Shantikumar V Nair
- Center for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham, Ponekkara, Kochi, 682 041, Kerala, India
| | - Anil Kumar Vasudevan
- Department of Microbiology, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham, Ponekkara, Kochi, 682 041, Kerala, India
| | - Raja Biswas
- Center for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham, Ponekkara, Kochi, 682 041, Kerala, India.
| | - Chethampadi Gopi Mohan
- Center for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham, Ponekkara, Kochi, 682 041, Kerala, India.
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Abstract
The peptidoglycan sacculus is a net-like polymer that surrounds the cytoplasmic membrane in most bacteria. It is essential to maintain the bacterial cell shape and protect from turgor. The peptidoglycan has a basic composition, common to all bacteria, with species-specific variations that can modify its biophysical properties or the pathogenicity of the bacteria. The synthesis of peptidoglycan starts in the cytoplasm and the precursor lipid II is flipped across the cytoplasmic membrane. The new peptidoglycan strands are synthesised and incorporated into the pre-existing sacculus by the coordinated activities of peptidoglycan synthases and hydrolases. In the model organism Escherichia coli there are two complexes required for the elongation and division. Each of them is regulated by different proteins from both the cytoplasmic and periplasmic sides that ensure the well-coordinated synthesis of new peptidoglycan.
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Sychantha D, Brott AS, Jones CS, Clarke AJ. Mechanistic Pathways for Peptidoglycan O-Acetylation and De-O-Acetylation. Front Microbiol 2018; 9:2332. [PMID: 30327644 PMCID: PMC6174289 DOI: 10.3389/fmicb.2018.02332] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 09/11/2018] [Indexed: 12/22/2022] Open
Abstract
The post-synthetic O-acetylation of the essential component of bacterial cell walls, peptidoglycan (PG), is performed by many pathogenic bacteria to help them evade the lytic action of innate immunity responses. Occurring at the C-6 hydroxyl of N-acetylmuramoyl residues, this modification to the glycan backbone of PG sterically blocks the activity of lysozymes. As such, the enzyme responsible for this modification in Gram-positive bacteria is recognized as a virulence factor. With Gram-negative bacteria, the O-acetylation of PG provides a means of control of their autolysins at the substrate level. In this review, we discuss the pathways for PG O-acetylation and de-O-acetylation and the structure and function relationship of the O-acetyltransferases and O-acetylesterases that catalyze these reactions. The current understanding of their mechanisms of action is presented and the prospects of targeting these systems for the development of novel therapeutics are explored.
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Affiliation(s)
| | | | | | - Anthony J. Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
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The increase of O-acetylation and N-deacetylation in cell wall promotes acid resistance and nisin production through improving cell wall integrity in Lactococcus lactis. ACTA ACUST UNITED AC 2018; 45:813-825. [DOI: 10.1007/s10295-018-2052-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 05/28/2018] [Indexed: 01/15/2023]
Abstract
Abstract
Cell wall is closely related to bacterial robustness and adsorption capacity, playing crucial roles in nisin production in Lactococcus lactis. Peptidoglycan (PG), the essential component of cell wall, is usually modified with MurNAc O-acetylation and GlcNAc N-deacetylation, catalyzed by YvhB and XynD, respectively. In this study, increasing the two modifications in L. lactis F44 improved autolysis resistance by decreasing the susceptibility to PG hydrolases. Furthermore, both modifications were positively associated with overall cross-linkage, contributing to cell wall integrity. The robust cell wall rendered the yvhB/xynD-overexpression strains more acid resistant, leading to the increase of nisin production in fed-batch fermentations by 63.7 and 62.9%, respectively. Importantly, the structural alterations also reduced nisin adsorption capacity, resulting in reduction of nisin loss. More strikingly, the co-overexpression strain displayed the highest nisin production (76.3% higher than F44). Our work provides a novel approach for achieving nisin overproduction via extensive cell wall remodeling.
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Yadav AK, Espaillat A, Cava F. Bacterial Strategies to Preserve Cell Wall Integrity Against Environmental Threats. Front Microbiol 2018; 9:2064. [PMID: 30233540 PMCID: PMC6127315 DOI: 10.3389/fmicb.2018.02064] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 08/13/2018] [Indexed: 12/18/2022] Open
Abstract
Bacterial cells are surrounded by an exoskeleton-like structure, the cell wall, composed primarily of the peptidoglycan (PG) sacculus. This structure is made up of glycan strands cross-linked by short peptides generating a covalent mesh that shapes bacteria and prevents their lysis due to their high internal osmotic pressure. Even though the PG is virtually universal in bacteria, there is a notable degree of diversity in its chemical structure. Modifications in both the sugars and peptides are known to be instrumental for bacteria to cope with diverse environmental challenges. In this review, we summarize and discuss the cell wall strategies to withstand biotic and abiotic environmental insults such as the effect of antibiotics targeting cell wall enzymes, predatory PG hydrolytic proteins, and PG signaling systems. Finally we will discuss the opportunities that species-specific PG variability might open to develop antimicrobial therapies.
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Affiliation(s)
- Akhilesh K Yadav
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Akbar Espaillat
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
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Ragland SA, Humbert MV, Christodoulides M, Criss AK. Neisseria gonorrhoeae employs two protein inhibitors to evade killing by human lysozyme. PLoS Pathog 2018; 14:e1007080. [PMID: 29975775 PMCID: PMC6033460 DOI: 10.1371/journal.ppat.1007080] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 05/08/2018] [Indexed: 12/25/2022] Open
Abstract
The bacterial pathogen Neisseria gonorrhoeae (Gc) infects mucosal sites rich in antimicrobial proteins, including the bacterial cell wall-degrading enzyme lysozyme. Certain Gram-negative bacteria produce protein inhibitors that bind to and inhibit lysozyme. Here, we identify Ng_1063 as a new inhibitor of lysozyme in Gc, and we define its functions in light of a second, recently identified lysozyme inhibitor, Ng_1981. In silico analyses indicated that Ng_1063 bears sequence and structural homology to MliC-type inhibitors of lysozyme. Recombinant Ng_1063 inhibited lysozyme-mediated killing of a susceptible mutant of Gc and the lysozyme-sensitive bacterium Micrococcus luteus. This inhibitory activity was dependent on serine 83 and lysine 103 of Ng_1063, which are predicted to interact with lysozyme’s active site residues. Lysozyme co-immunoprecipitated with Ng_1063 and Ng_1981 from intact Gc. Ng_1063 and Ng_1981 protein levels were also increased in Gc exposed to lysozyme. Gc lacking both ng1063 and ng1981 was significantly more sensitive to killing by lysozyme than wild-type or single mutant bacteria. When exposed to human tears or saliva, in which lysozyme is abundant, survival of Δ1981Δ1063 Gc was significantly reduced compared to wild-type, and survival was restored upon addition of recombinant Ng_1981. Δ1981Δ1063 mutant Gc survival was additionally reduced in the presence of human neutrophils, which produce lysozyme. We found that while Ng_1063 was exposed on the surface of Gc, Ng_1981 was both in an intracellular pool and extracellularly released from the bacteria, suggesting that Gc employs these two proteins at multiple spatial barriers to fully neutralize lysozyme activity. Together, these findings identify Ng_1063 and Ng_1981 as critical components for Gc defense against lysozyme. These proteins may be attractive targets for antimicrobial therapy aimed to render Gc susceptible to host defenses and/or for vaccine development, both of which are urgently needed against drug-resistant gonorrhea. The mucosal pathogen Neisseria gonorrhoeae has acquired resistance to almost all recommended antibiotics, and no gonorrhea vaccine currently exists. Attractive targets for therapeutic discovery include bacterial factors that, when inactivated, enhance bacterial susceptibility to host-derived antimicrobial components. The bacterial cell wall-degrading enzyme lysozyme is abundant in mucosal secretions and innate immune cells. To resist killing by lysozyme, some bacteria produce proteins that bind to and directly inhibit the activity of lysozyme. Here, we demonstrate lysozyme inhibitory activity in the N. gonorrhoeae protein Ng_1063. We found that both Ng_1063 and a second, recently described lysozyme inhibitor, Ng_1981, contribute to full resistance of N. gonorrhoeae to lysozyme, including resistance to lysozyme-rich mucosal secretions and human neutrophils. Although Ng_1063 and Ng_1981 are both inhibitors of lysozyme, they are distinct in their sequences, biological activities, and cellular localizations. Because both Ng_1063 and Ng_1981 are extracellular, we propose they can be targeted for vaccines and drugs that sensitize Gc to human antimicrobial defenses.
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Affiliation(s)
- Stephanie A. Ragland
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Marίa V. Humbert
- Neisseria Research, Molecular Microbiology, Academic Unit of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton, United Kingdom
| | - Myron Christodoulides
- Neisseria Research, Molecular Microbiology, Academic Unit of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton, United Kingdom
| | - Alison K. Criss
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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Structure-function studies of prothrombin Amrita, a dysfunctional prothrombin characterized by point mutation at Arg553 → Gln. Int J Biol Macromol 2018; 110:550-557. [DOI: 10.1016/j.ijbiomac.2018.01.084] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/19/2017] [Accepted: 01/13/2018] [Indexed: 11/19/2022]
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40
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Understanding the adhesion mechanism of a mucin binding domain from Lactobacillus fermentum and its role in enteropathogen exclusion. Int J Biol Macromol 2018; 110:598-607. [DOI: 10.1016/j.ijbiomac.2017.10.107] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/13/2017] [Accepted: 10/16/2017] [Indexed: 12/21/2022]
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41
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Pullulan-based nanocomposite films for functional food packaging: Exploiting lysozyme nanofibers as antibacterial and antioxidant reinforcing additives. Food Hydrocoll 2018. [DOI: 10.1016/j.foodhyd.2017.11.039] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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In vitro characterization of the antivirulence target of Gram-positive pathogens, peptidoglycan O-acetyltransferase A (OatA). PLoS Pathog 2017; 13:e1006667. [PMID: 29077761 PMCID: PMC5697884 DOI: 10.1371/journal.ppat.1006667] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/21/2017] [Accepted: 09/25/2017] [Indexed: 12/17/2022] Open
Abstract
The O-acetylation of the essential cell wall polymer peptidoglycan occurs in most Gram-positive bacterial pathogens, including species of Staphylococcus, Streptococcus and Enterococcus. This modification to peptidoglycan protects these pathogens from the lytic action of the lysozymes of innate immunity systems and, as such, is recognized as a virulence factor. The key enzyme involved, peptidoglycan O-acetyltransferase A (OatA) represents a particular challenge to biochemical study since it is a membrane associated protein whose substrate is the insoluble peptidoglycan cell wall polymer. OatA is predicted to be bimodular, being comprised of an N-terminal integral membrane domain linked to a C-terminal extracytoplasmic domain. We present herein the first biochemical and kinetic characterization of the C-terminal catalytic domain of OatA from two important human pathogens, Staphylococcus aureus and Streptococcus pneumoniae. Using both pseudosubstrates and novel biosynthetically-prepared peptidoglycan polymers, we characterized distinct substrate specificities for the two enzymes. In addition, the high resolution crystal structure of the C-terminal domain reveals an SGNH/GDSL-like hydrolase fold with a catalytic triad of amino acids but with a non-canonical oxyanion hole structure. Site-specific replacements confirmed the identity of the catalytic and oxyanion hole residues. A model is presented for the O-acetylation of peptidoglycan whereby the translocation of acetyl groups from a cytoplasmic source across the cytoplasmic membrane is catalyzed by the N-terminal domain of OatA for their transfer to peptidoglycan by its C-terminal domain. This study on the structure-function relationship of OatA provides a molecular and mechanistic understanding of this bacterial resistance mechanism opening the prospect for novel chemotherapeutic exploration to enhance innate immunity protection against Gram-positive pathogens. Multi-drug resistance amongst important human pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE) and drug-resistant Streptococcus pneumoniae (DRSP), continues to challenge clinicians and threaten the lives of infected patients. Of the several approaches being taken to address this serious issue is the development of antagonists that render the bacterial infection more susceptible to the defensive enzymes and proteins of our innate immunity systems. One such target is the enzyme O-acetyltransferase A (OatA). This extracellular enzyme modifies the essential bacterial cell wall component peptidoglycan and thereby makes it resistant to the lytic action of lysozyme, our first line of defense against invading pathogens. In this study, we present the first biochemical and structural characterization of OatA. Using both the S. aureus and S. pneumoniae enzymes as model systems, we demonstrate that OatA has unique substrate specificities. We also show that the catalytic domain of OatA is a structural homolog of a well-studied superfamily of hydrolases. It uses a catalytic triad of Ser-His-Asp to transfer acetyl groups specifically to the C-6 hydroxyl group of muramoyl residues within peptidoglycan. This information on the structure and function relationship of OatA is important for the future development of effective inhibitors which may serve as antivirulence agents.
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Impact of cell wall peptidoglycan O- acetylation on the pathogenesis of Staphylococcus aureus in septic arthritis. Int J Med Microbiol 2017; 307:388-397. [DOI: 10.1016/j.ijmm.2017.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/18/2017] [Accepted: 08/04/2017] [Indexed: 02/02/2023] Open
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Abstract
Lysozyme is a cornerstone of innate immunity. The canonical mechanism for bacterial killing by lysozyme occurs through the hydrolysis of cell wall peptidoglycan (PG). Conventional type (c-type) lysozymes are also highly cationic and can kill certain bacteria independently of PG hydrolytic activity. Reflecting the ongoing arms race between host and invading microorganisms, both gram-positive and gram-negative bacteria have evolved mechanisms to thwart killing by lysozyme. In addition to its direct antimicrobial role, more recent evidence has shown that lysozyme modulates the host immune response to infection. The degradation and lysis of bacteria by lysozyme enhance the release of bacterial products, including PG, that activate pattern recognition receptors in host cells. Yet paradoxically, lysozyme is important for the resolution of inflammation at mucosal sites. This review will highlight recent advances in our understanding of the diverse mechanisms that bacteria use to protect themselves against lysozyme, the intriguing immunomodulatory function of lysozyme, and the relationship between these features in the context of infection.
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Affiliation(s)
- Stephanie A. Ragland
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Alison K. Criss
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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Gao X, Guo M, Zhang Z, Shen P, Yang Z, Zhang N. Baicalin promotes the bacteriostatic activity of lysozyme on S. aureus in mammary glands and neutrophilic granulocytes in mice. Oncotarget 2017; 8:19894-19901. [PMID: 28184027 PMCID: PMC5386731 DOI: 10.18632/oncotarget.15193] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 11/22/2016] [Indexed: 12/15/2022] Open
Abstract
Staphylococcus aureus causes mastitis as a result of community-acquired or nosocomial infections. Lysozyme (LYSO) is an enzyme that is upregulated in many organisms during the innate immune response against infection by bacterial pathogens. Baicalin is a bioactive flavonoid that can bind to enzymes, often to potentiate their effect. Here we tested the effects of baicalin on the activity of LYSO using the S. aureus mastitis mouse model and neutrophilic granulocyte model of S. aureus infection. In our experiments, S. aureus counts decreased with increasing baicalin concentration. Furthermore, qPCR and western blot analyses showed that LYSO expression was unaffected by baicalin, while fluorescence quenching and UV fluorescence spectral analyses showed that baicalin binds to LYSO. To test whether this binding increased LYSO activity, we assessed LYSO-induced bacteriostasis in the presence of baicalin. Our results showed that LYSO-induced S. aureus bacteriostasis increased with increasing concentrations of baicalin, and that baicalin binding to LYSO synergistically increased the antibacterial activity of LYSO. These results demonstrate that baicalin enhances LYSO-induced bacteriostasis during the innate immune response to S. aureus. They suggest baicalin is a potentially useful therapeutic agent for the treatment of bacterial infections.
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Affiliation(s)
- Xuejiao Gao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, Jilin Province 130062, People's Republic of China
| | - Mengyao Guo
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Zecai Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, Jilin Province 130062, People's Republic of China
| | - Peng Shen
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, Jilin Province 130062, People's Republic of China
| | - Zhengtao Yang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, Jilin Province 130062, People's Republic of China
| | - Naisheng Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, Jilin Province 130062, People's Republic of China
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Understanding the molecular differential recognition of muramyl peptide ligands by LRR domains of human NOD receptors. Biochem J 2017; 474:2691-2711. [DOI: 10.1042/bcj20170220] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/27/2017] [Accepted: 07/03/2017] [Indexed: 12/28/2022]
Abstract
Human nucleotide-binding oligomerization domain proteins, hNOD1 and hNOD2, are host intracellular receptors with C-terminal leucine-rich repeat (LRR) domains, which recognize specific bacterial peptidoglycan (PG) fragments as their ligands. The specificity of this recognition is dependent on the third amino acid of the stem peptide of the PG ligand, which is usually meso-diaminopimelic acid (mesoDAP) or l-lysine (l-Lys). Since the LRR domains of hNOD receptors had been experimentally shown to confer the PG ligand-sensing specificity, we developed three-dimensional structures of hNOD1-LRR and the hNOD2-LRR to understand the mechanism of differential recognition of muramyl peptide ligands by hNOD receptors. The hNOD1-LRR and hNOD2-LRR receptor models exhibited right-handed curved solenoid shape. The hot-spot residues experimentally proved to be critical for ligand recognition were located in the concavity of the NOD-LRR and formed the recognition site. Our molecular docking analyses and molecular electrostatic potential mapping studies explain the activation of hNOD-LRRs, in response to effective molecular interactions of PG ligands at the recognition site; and conversely, the inability of certain PG ligands to activate hNOD-LRRs, by deviations from the recognition site. Based on molecular docking studies using PG ligands, we propose few residues — G825, D826 and N850 in hNOD1-LRR and L904, G905, W931, L932 and S933 in hNOD2-LRR, evolutionarily conserved across different host species, which may play a major role in ligand recognition. Thus, our integrated experimental and computational approach elucidates the molecular basis underlying the differential recognition of PG ligands by hNOD receptors.
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Abouhmad A, Dishisha T, Amin MA, Hatti-Kaul R. Immobilization to Positively Charged Cellulose Nanocrystals Enhances the Antibacterial Activity and Stability of Hen Egg White and T4 Lysozyme. Biomacromolecules 2017; 18:1600-1608. [DOI: 10.1021/acs.biomac.7b00219] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Adel Abouhmad
- Biotechnology,
Department of Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O.
Box 124, SE-221 00 Lund, Sweden
- Department
of Microbiology and Immunology, Faculty of Pharmacy, Al-Azhar University, 715
24 Assiut, Egypt
| | - Tarek Dishisha
- Department
of Microbiology and Immunology, Faculty of Pharmacy, Beni-Suef University, 625 11 Beni-Suef, Egypt
| | - Magdy A. Amin
- Department
of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, 115 62 Cairo, Egypt
| | - Rajni Hatti-Kaul
- Biotechnology,
Department of Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O.
Box 124, SE-221 00 Lund, Sweden
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Bacterial peptidoglycan with amidated meso-diaminopimelic acid evades NOD1 recognition: an insight into NOD1 structure–recognition. Biochem J 2016; 473:4573-4592. [DOI: 10.1042/bcj20160817] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/04/2016] [Accepted: 10/14/2016] [Indexed: 12/16/2022]
Abstract
Nucleotide-binding oligomerization domain-containing protein 1 (NOD1) is an intracellular pattern recognition receptor that recognizes bacterial peptidoglycan (PG) containing meso-diaminopimelic acid (mesoDAP) and activates the innate immune system. Interestingly, a few pathogenic and commensal bacteria modify their PG stem peptide by amidation of mesoDAP (mesoDAPNH2). In the present study, NOD1 stimulation assays were performed using bacterial PG containing mesoDAP (PGDAP) and mesoDAPNH2 (PGDAPNH2) to understand the differences in their biomolecular recognition mechanism. PGDAP was effectively recognized, whereas PGDAPNH2 showed reduced recognition by the NOD1 receptor. Restimulation of the NOD1 receptor, which was initially stimulated with PGDAP using PGDAPNH2, did not show any further NOD1 activation levels than with PGDAP alone. But the NOD1 receptor initially stimulated with PGDAPNH2 responded effectively to restimulation with PGDAP. The biomolecular structure–recognition relationship of the ligand-sensing leucine-rich repeat (LRR) domain of human NOD1 (NOD1–LRR) with PGDAP and PGDAPNH2 was studied by different computational techniques to further understand the molecular basis of our experimental observations. The d-Glu–mesoDAP motif of GMTPDAP, which is the minimum essential motif for NOD1 activation, was found involved in specific interactions at the recognition site, but the interactions of the corresponding d-Glu–mesoDAP motif of PGDAPNH2 occur away from the recognition site of the NOD1 receptor. Hot-spot residues identified for effective PG recognition by NOD1–LRR include W820, G821, D826 and N850, which are evolutionarily conserved across different host species. These integrated results thus successfully provided the atomic level and biochemical insights on how PGs containing mesoDAPNH2 evade NOD1–LRR receptor recognition.
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Mladineo I, Bušelić I, Hrabar J, Radonić I, Vrbatović A, Jozić S, Trumbić Ž. Autochthonous Bacterial Isolates Successfully Stimulate In vitro Peripheral Blood Leukocytes of the European Sea Bass (Dicentrarchus labrax). Front Microbiol 2016; 7:1244. [PMID: 27551281 PMCID: PMC4976100 DOI: 10.3389/fmicb.2016.01244] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 07/26/2016] [Indexed: 11/20/2022] Open
Abstract
Commercially available probiotics are routinely administered as feed supplements in aquaculture important species. Among them, the European sea bass (Dicentrarchus labrax) is the most widely reared fish in the Mediterranean, whose rearing systems are highly variable between countries, affecting at some level the sustainability of production. After random isolation of autochthonous gut bacteria of the sea bass, their identification and pathogenicity testing, we have selected three potentially probiotic isolates; Pseudoalteromonas sp., Alteromonas sp., and Enterovibrio coralii. Selected isolates were tested and their immunostimulative efficiency was compared with a commercially available Lactobacillus casei isolate, inferring inflammatory, apoptotic and anti-pathogen response of sea bass’ peripheral blood leukocytes. Phagocytic activity, respiratory burst, and expression of lysozyme, Mx protein, caspase 3, TNF-α, IL-10 genes was measured 1, 3, 5, and 12 h post-stimulation by four bacterial isolates to evaluate early kinetics of the responses. Best immunostimulative properties were observed in Pseudoalteromonas-stimulated leukocytes, followed by Alteromonas sp. and L. casei, while Enterovibrio coralii failed to induce significant stimulation. Based on such in vitro assay intestinal autochthonous bacterial isolates showed to have better immunostimulative effect in sea bass compared to aquaculture-widely used L. casei, and further steps need to engage tank and field feeding trials to evaluate long-term prophylactic suitability of the chosen isolates. A panel of biomarkers that represent pro-/anti-inflammatory, pro-/anti-apoptotic, and anti-bacteria/viral responses of the fish should be taken into consideration when evaluating the usefulness of the potential probiotic in aquaculture.
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Affiliation(s)
| | - Ivana Bušelić
- Institute of Oceanography and Fisheries Split, Croatia
| | - Jerko Hrabar
- Institute of Oceanography and Fisheries Split, Croatia
| | - Ivana Radonić
- Institute of Oceanography and Fisheries Split, Croatia
| | | | - Slaven Jozić
- Institute of Oceanography and Fisheries Split, Croatia
| | - Željka Trumbić
- Department of Marine Studies, University of Split Split, Croatia
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Giles-Gómez M, Sandoval García JG, Matus V, Campos Quintana I, Bolívar F, Escalante A. In vitro and in vivo probiotic assessment of Leuconostoc mesenteroides P45 isolated from pulque, a Mexican traditional alcoholic beverage. SPRINGERPLUS 2016; 5:708. [PMID: 27375977 PMCID: PMC4906094 DOI: 10.1186/s40064-016-2370-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 05/19/2016] [Indexed: 11/10/2022]
Abstract
Pulque is a Mexican traditional alcoholic, non-distilled, fermented beverage produced by the fermentation of the sap, known as aguamiel, extracted from several maguey (Agave) species. Pulque has traditionally been considered a healthy beverage due to its nutrient content and also a traditional medicine for the treatment of gastrointestinal disorders and intestinal infections. During pulque fermentation, the development of acidity, alcohol and viscosity define its final sensorial properties, developing an enriched environment where dominant lactic acid bacteria (LAB), including diverse Leuconostoc species, are present. Because traditional pulque is consumed directly from the fermentation vessel, the naturally associated LAB are ingested and reach the human small intestine alive. Here, we report the in vitro and in vivo probiotic assessment of Leuconostoc mesenteroides strain P45 isolated from pulque. This isolated LAB species exhibited lysozyme, acid (pH 3.5) and bile salts (0.1 and 0.3 % oxgall) resistance. Antibacterial activity against the pathogens Listeria monocytogenes, enteropathogenic Escherichia coli, Salmonella enterica serovar Typhi and S. enterica serovar Typhimurium were observed in assays involving cell-to-cell contact, cell-free 2× concentrated supernatants and cell-to-cell contact under exopolysaccharide-producing conditions. The in vivo probiotic assessment showed an anti-infective activity of L. mesenteroides P45 against S. enterica serovar Typhimurium in challenged male and female BALB/c mice. Analysis of the available genome sequence of strain P45 allowed identified a pre-bacteriocin coding gene and six peptidoglycan hydrolase enzymes, probably involved in the antimicrobial activity of this strain. The results presented in this study support some potential microbial mechanisms associated with the beneficial effects on human health of this LAB involved in the fermentation of pulque.
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Affiliation(s)
- Martha Giles-Gómez
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán, 04510 Ciudad de México, México
| | - Jorge Giovanni Sandoval García
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán, 04510 Ciudad de México, México
| | - Violeta Matus
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, 62210 Cuernavaca, Morelos México
| | - Itzia Campos Quintana
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán, 04510 Ciudad de México, México
| | - Francisco Bolívar
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, 62210 Cuernavaca, Morelos México
| | - Adelfo Escalante
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, 62210 Cuernavaca, Morelos México
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