1
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Gao N, Wang J, Fang C, Bai P, Sun Y, Wu W, Shan A. Combating bacterial infections with host defense peptides: Shifting focus from bacteria to host immunity. Drug Resist Updat 2024; 72:101030. [PMID: 38043443 DOI: 10.1016/j.drup.2023.101030] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/12/2023] [Accepted: 11/26/2023] [Indexed: 12/05/2023]
Abstract
The increasing prevalence of multidrug-resistant bacterial infections necessitates the exploration of novel paradigms for anti-infective therapy. Antimicrobial peptides (AMPs), also known as host defense peptides (HDPs), have garnered extensive recognition as immunomodulatory molecules that leverage natural host mechanisms to enhance therapeutic benefits. The unique immune mechanism exhibited by certain HDPs that involves self-assembly into supramolecular nanonets capable of inducing bacterial agglutination and entrapping is significantly important. This process effectively prevents microbial invasion and subsequent dissemination and significantly mitigates selective pressure for the evolution of microbial resistance, highlighting the potential of HDP-based antimicrobial therapy. Recent advancements in this field have focused on developing bio-responsive materials in the form of supramolecular nanonets. A comprehensive overview of the immunomodulatory and bacteria-agglutinating activities of HDPs, along with a discussion on optimization strategies for synthetic derivatives, is presented in this article. These optimized derivatives exhibit improved biological properties and therapeutic potential, making them suitable for future clinical applications as effective anti-infective therapeutics.
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Affiliation(s)
- Nan Gao
- Animal Science and Technology College, Northeast Agricultural University, Harbin 150030, PR China
| | - Jiajun Wang
- Animal Science and Technology College, Northeast Agricultural University, Harbin 150030, PR China.
| | - Chunyang Fang
- Animal Science and Technology College, Northeast Agricultural University, Harbin 150030, PR China
| | - Pengfei Bai
- Animal Science and Technology College, Northeast Agricultural University, Harbin 150030, PR China
| | - Yu Sun
- Animal Science and Technology College, Northeast Agricultural University, Harbin 150030, PR China
| | - Wanpeng Wu
- Animal Science and Technology College, Northeast Agricultural University, Harbin 150030, PR China
| | - Anshan Shan
- Animal Science and Technology College, Northeast Agricultural University, Harbin 150030, PR China.
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2
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Bortolotti A, Troiano C, Bobone S, Konai MM, Ghosh C, Bocchinfuso G, Acharya Y, Santucci V, Bonacorsi S, Di Stefano C, Haldar J, Stella L. Mechanism of lipid bilayer perturbation by bactericidal membrane-active small molecules. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184079. [PMID: 36374761 DOI: 10.1016/j.bbamem.2022.184079] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 10/21/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022]
Abstract
Membrane-active small molecules (MASMs) are small organic molecules designed to reproduce the fundamental physicochemical properties of natural antimicrobial peptides: their cationic charge and amphiphilic character. This class of compounds has a promising broad range of antimicrobial activity and, at the same time, solves some major limitations of the peptides, such as their high production costs and low in vivo stability. Most cationic antimicrobial peptides act by accumulating on the surface of bacterial membranes and causing the formation of defects when a threshold is reached. Due to the drastically different structures of the two classes of molecules, it is not obvious that small-molecule antimicrobials act in the same way as natural peptides, and very few data are available on this aspect. Here we combined spectroscopic studies and molecular dynamics simulations to characterize the mechanism of action of two different MASMs. Our results show that, notwithstanding their simple structure, these molecules act just like antimicrobial peptides. They bind to the membrane surface, below the head-groups, and insert their apolar moieties in the core of the bilayer. Like many natural peptides, they cause the formation of defects when they reach a high coverage of the membrane surface. In addition, they cause membrane aggregation, and this property could contribute to their antimicrobial activity.
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Affiliation(s)
- A Bortolotti
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - C Troiano
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - S Bobone
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - M M Konai
- Antimicrobial Research Laboratory, New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru 560064, Karnataka, India
| | - C Ghosh
- Antimicrobial Research Laboratory, New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru 560064, Karnataka, India
| | - G Bocchinfuso
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Y Acharya
- Antimicrobial Research Laboratory, New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru 560064, Karnataka, India
| | - V Santucci
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - S Bonacorsi
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - C Di Stefano
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - J Haldar
- Antimicrobial Research Laboratory, New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru 560064, Karnataka, India; School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru 560064, Karnataka, India.
| | - L Stella
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy.
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3
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Gorr SU, Brigman HV, Anderson JC, Hirsch EB. The antimicrobial peptide DGL13K is active against drug-resistant gram-negative bacteria and sub-inhibitory concentrations stimulate bacterial growth without causing resistance. PLoS One 2022; 17:e0273504. [PMID: 36006947 PMCID: PMC9409508 DOI: 10.1371/journal.pone.0273504] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 08/09/2022] [Indexed: 11/19/2022] Open
Abstract
Antimicrobial peptides may be alternatives to traditional antibiotics with reduced bacterial resistance. The antimicrobial peptide GL13K was derived from the salivary protein BPIFA2. This study determined the relative activity of the L-and D-enantiomers of GL13K to wild-type and drug-resistant strains of three gram-negative species and against Pseudomonas aeruginosa biofilms. DGL13K displayed in vitro activity against extended-spectrum beta-lactamase (ESBL)-producing and Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae (MICs 16-32 μg/ml), MDR and XDR P. aeruginosa, and XDR Acinetobacter baumannii carrying metallo-beta-lactamases (MICs 8-32 μg/ml). P. aeruginosa showed low inherent resistance to DGL13K and the increased metabolic activity and growth caused by sub-MIC concentrations of GL13K peptides did not result in acquired bacterial resistance. Daily treatment for approximately two weeks did not increase the MIC of DGL13K or cause cross-resistance between LGL13K and DGL13K. These data suggest that DGL13K is a promising antimicrobial peptide candidate for further development.
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Affiliation(s)
- Sven-Ulrik Gorr
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, United States of America
| | - Hunter V. Brigman
- Department of Experimental and Clinical Pharmacology, University of Minnesota College of Pharmacy, Minneapolis, Minnesota, United States of America
| | - Jadyn C. Anderson
- Department of Experimental and Clinical Pharmacology, University of Minnesota College of Pharmacy, Minneapolis, Minnesota, United States of America
| | - Elizabeth B. Hirsch
- Department of Experimental and Clinical Pharmacology, University of Minnesota College of Pharmacy, Minneapolis, Minnesota, United States of America
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Escobar‐Salom M, Torrens G, Jordana‐Lluch E, Oliver A, Juan C. Mammals' humoral immune proteins and peptides targeting the bacterial envelope: from natural protection to therapeutic applications against multidrug‐resistant
Gram
‐negatives. Biol Rev Camb Philos Soc 2022; 97:1005-1037. [PMID: 35043558 PMCID: PMC9304279 DOI: 10.1111/brv.12830] [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: 05/18/2021] [Revised: 12/12/2021] [Accepted: 12/15/2021] [Indexed: 12/11/2022]
Abstract
Mammalian innate immunity employs several humoral ‘weapons’ that target the bacterial envelope. The threats posed by the multidrug‐resistant ‘ESKAPE’ Gram‐negative pathogens (Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) are forcing researchers to explore new therapeutic options, including the use of these immune elements. Here we review bacterial envelope‐targeting (peptidoglycan and/or membrane‐targeting) proteins/peptides of the mammalian immune system that are most likely to have therapeutic applications. Firstly we discuss their general features and protective activity against ESKAPE Gram‐negatives in the host. We then gather, integrate, and discuss recent research on experimental therapeutics harnessing their bactericidal power, based on their exogenous administration and also on the discovery of bacterial and/or host targets that improve the performance of this endogenous immunity, as a novel therapeutic concept. We identify weak points and knowledge gaps in current research in this field and suggest areas for future work to obtain successful envelope‐targeting therapeutic options to tackle the challenge of antimicrobial resistance.
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Affiliation(s)
- María Escobar‐Salom
- Department of Microbiology University Hospital Son Espases‐Health Research Institute of the Balearic Islands (IdISBa) Carretera de Valldemossa 79 Palma Balearic Islands 07010 Spain
| | - Gabriel Torrens
- Department of Microbiology University Hospital Son Espases‐Health Research Institute of the Balearic Islands (IdISBa) Carretera de Valldemossa 79 Palma Balearic Islands 07010 Spain
| | - Elena Jordana‐Lluch
- Department of Microbiology University Hospital Son Espases‐Health Research Institute of the Balearic Islands (IdISBa) Carretera de Valldemossa 79 Palma Balearic Islands 07010 Spain
| | - Antonio Oliver
- Department of Microbiology University Hospital Son Espases‐Health Research Institute of the Balearic Islands (IdISBa) Carretera de Valldemossa 79 Palma Balearic Islands 07010 Spain
| | - Carlos Juan
- Department of Microbiology University Hospital Son Espases‐Health Research Institute of the Balearic Islands (IdISBa) Carretera de Valldemossa 79 Palma Balearic Islands 07010 Spain
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5
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Chen D, Li J, Pan T, Wu R, Tao Y, Lin H. The broad-spectrum antibiofilm activity of amyloid-forming hexapeptides. Microb Biotechnol 2020; 14:656-667. [PMID: 33248016 PMCID: PMC7936291 DOI: 10.1111/1751-7915.13721] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 11/12/2020] [Indexed: 01/25/2023] Open
Abstract
Evidence suggests that short amyloid-forming peptides derived from bacterial proteomes have functional roles; however, the reported activities are diverse and the underlying mechanisms remain unclear. In this study, we simulated short amyloid-forming peptides from the amyloid-forming truncated protein C123 of Streptococcus mutans (S. mutans), studied their biological functions in microbial proliferation and biofilm formation, and further investigated the underlying mechanism. Fourteen hexapeptides were simulated, 13 of which were successfully synthesized. We found that the amyloid-forming hexapeptides (AFhPs) displayed efficient broad-spectrum antibiofilm activity against the Gram-positive bacteria S. mutans, Streptococcus sanguis and Staphylococcus aureus, Gram-negative bacteria Escherichia coli and fungus Candida albicans, by aggregating into rigid amyloid fibres agglutinating microbes, whereas the non-amyloid-forming hexapeptides (non-AFhPs) did not. The AFhPs did not kill microbes and showed little or no cytotoxicity. Furthermore, a set of AFhPs displayed broad-spectrum antibiofilm activity, regardless of its source. The microbial cell wall carbohydrates, peptidoglycan (PGN), lipoteichoic acid (LTA), glucan and zymosan A, mediated AFhP binding and triggered significant AFhP fibrillation. Although amyloid fibres agglutinated lipid membrane model - large unilamellar vesicles (LUVs) - and LUVs facilitated AFhP fibrillation, the roles of lipid membranes in AFhP antibiofilm activities remain to be elucidated. We highlight the potential use of AFhPs as novel antibiofilm agents.
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Affiliation(s)
- Dongru Chen
- Guangdong Provincial Key Laboratory of Stomatology, Department of Orthodontics, Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jing Li
- Guangdong Provincial Key Laboratory of Stomatology, Department of Preventive Dentistry, Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Ting Pan
- Guangdong Provincial Key Laboratory of Stomatology, Department of Preventive Dentistry, Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Ruixue Wu
- Guangdong Provincial Key Laboratory of Stomatology, Department of Preventive Dentistry, Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Ye Tao
- Guangdong Provincial Key Laboratory of Stomatology, Department of Preventive Dentistry, Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Huancai Lin
- Guangdong Provincial Key Laboratory of Stomatology, Department of Preventive Dentistry, Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
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6
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Perdigão J. Current perspectives on dental adhesion: (1) Dentin adhesion - not there yet. JAPANESE DENTAL SCIENCE REVIEW 2020; 56:190-207. [PMID: 34188727 PMCID: PMC8216299 DOI: 10.1016/j.jdsr.2020.08.004] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/24/2020] [Indexed: 12/11/2022] Open
Abstract
The essential goal of any adhesive restoration is to achieve a tight and long-lasting adaptation of the restorative material to enamel and dentin. The key challenge for new dental adhesives is to be simultaneously effective on two dental substrates of conflicting nature. Some barriers must be overcome to accomplish this objective. While bonding to enamel by micromechanical interlocking of resin tags within the array of microporosities in acid-etched enamel can be reliably achieved and can effectively seal the restoration margins against leakage, bonding effectively and durably to organic and humid dentin is the most puzzling task in adhesive dentistry. Much of the research and development of dental adhesives has focused on making the clinical procedure more user-friendly by reducing the number of bottles and/or steps. Although clinicians certainly prefer less complicated and more versatile adhesive materials, there is a trade-off between simplification of dental adhesives and clinical outcomes. Likewise, new materials are launched with claims of being novel and having special properties without much supporting evidence. This review article discusses dental adhesion acknowledging pioneer work in the field, highlights the substrate as a major challenge to obtain durable adhesive restorations, as well as analyzes the three adhesion strategies and their shortcomings. It also reviews the potential of chemical/ionic dental adhesion, discusses the issue of extensively published laboratory research that does not translate to clinical relevance, and leaves a few thoughts in regard to recent research that may have implications for future adhesive materials.
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Affiliation(s)
- Jorge Perdigão
- Professor, University of Minnesota, Department of Restorative Sciences, 515 SE Delaware St, 8-450 Moos Tower, Minneapolis, MN 55455, USA
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7
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Bagheri M, Nikolenko H, Arasteh S, Rezaei N, Behzadi M, Dathe M, Hancock REW. Bacterial Aggregation Triggered by Fibril Forming Tryptophan-Rich Sequences: Effects of Peptide Side Chain and Membrane Phospholipids. ACS APPLIED MATERIALS & INTERFACES 2020; 12:26852-26867. [PMID: 32422035 DOI: 10.1021/acsami.0c04336] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The influence of side chain residue and phospholipid characteristics of the cytoplasmic membrane upon the fibrillation and bacterial aggregation of arginine (Arg) and tryptophan (Trp) rich antimicrobial peptides (AMPs) has not been well described to date. Here, we utilized the structural advantages of HHC-10 and 4HarHHC-10 (Har, l-homoarginine) that are highly active Trp-rich AMPs and investigated their fibril formation and activity behavior against bacteria. The peptides revealed time-dependent self-assembly of polyproline II (PPII) α-helices, but by comparison, 4HarHHC-10 tended to form higher ordered fibrils due to relatively strong cation-π stacking of Trp with Har residue. Both peptides rapidly killed S. aureus and E. coli at their MICs and caused aggregation of bacteria at higher concentrations. This bacterial aggregation was accompanied by the formation of morphologically distinct electron-dense nanostructures, likely including but not limited to peptides alone. Both HHC-10-derived peptides caused blebs and buds in the E. coli membrane that are rich in POPE phospholipid that promotes negative curvature. However, the main population of S. aureus cells retained their cocci structure upon treatment with HHC peptides even at concentration higher than the MICs. In contrast, the cell aggregation was not induced by HHC fibrils that were most likely stabilized through intra-/intermolecular cation-π stacking. It is proposed that masking of these interactions might have resulted in diminished membrane association/insertion of the HHC nanostructures. The peptides caused aggregation of POPC/POPG (1/3) and POPE/POPG (3/1) liposomes. Nonetheless, disaggregation of the former vesicles was observed at ratios of lipid to peptide of greater than 6 and 24 for HHC-10 and 4HarHHC-10, respectively. Collectively, our results revealed dose-dependent bacterial aggregation mediated by Trp-rich AMPs that was profoundly influenced by the degree of peptide's self-association and the composition and intrinsic curvature of the cytoplasmic membrane lipids.
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Affiliation(s)
- Mojtaba Bagheri
- Peptide Chemistry Laboratory, Institute of Biochemistry and Biophysics, University of Tehran, 16 Azar Street, 14176-14335 Tehran, Iran
| | - Heike Nikolenko
- Peptide-Lipid Interaction, Department of Chemical Biology, Leibniz Institute of Molecular Pharmacology, Robert-Roessle-Strasse 10, 13125 Berlin, Germany
| | - Shima Arasteh
- Peptide Chemistry Laboratory, Institute of Biochemistry and Biophysics, University of Tehran, 16 Azar Street, 14176-14335 Tehran, Iran
| | - Nakisa Rezaei
- Peptide Chemistry Laboratory, Institute of Biochemistry and Biophysics, University of Tehran, 16 Azar Street, 14176-14335 Tehran, Iran
| | - Malihe Behzadi
- Peptide Chemistry Laboratory, Institute of Biochemistry and Biophysics, University of Tehran, 16 Azar Street, 14176-14335 Tehran, Iran
| | - Margitta Dathe
- Peptide-Lipid Interaction, Department of Chemical Biology, Leibniz Institute of Molecular Pharmacology, Robert-Roessle-Strasse 10, 13125 Berlin, Germany
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, 2259 Lower Mall Research Station, Vancouver, British Columbia V6T 1Z4, Canada
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8
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Moussa DG, Kirihara JA, Ye Z, Fischer NG, Khot J, Witthuhn BA, Aparicio C. Dentin Priming with Amphipathic Antimicrobial Peptides. J Dent Res 2019; 98:1112-1121. [PMID: 31313946 DOI: 10.1177/0022034519863772] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The evolution of bonded restorations has undergone great progress over several decades. Nonetheless, life spans of bonded restorations are limited mainly because of the eventual incidence of recurrent caries. Over time, water and waterborne agents (acids, enzymes) degrade the components of the dentin/restoration interface, allowing bacterial colonization and dentin reinfection at the margins of the restoration. We developed a 2-tier protective technology consisting of priming/coating dentin with amphipathic and antimicrobial peptides (AAMPs) to obtain hydrophobic/water-repellent and antibiofilm dentin-resisting recurrent caries around bonded restorations. We tested a series of AAMPs to assess their structure-function relationships as well as the effects of different dentin-conditioning methods on the structural features of AAMP-coated dentin. We found relation between the secondary structure of AAMPs (high portion of β-sheet), the antimicrobial potency of AAMPs, and the AAMPs' ability to form hydrophobic coatings on dentin. We also determined that AAMPs had preferential adsorption on the mineral phase of dentin, which suggested that peptides arrange their cationic and hydrophilic motifs in direct contact with the negatively charged minerals in the hydrophilic dentin. These results led us to explore different dentin-conditioning methods that would increase the mineral/collagen ratio and their effect on AAMP immobilization. We innovatively imaged the spatial distribution of the AAMPs in relation to the dentinal tubules and collagen network using a minimally invasive multimodal imaging technique: multiphoton-second harmonic generation. Using multiphoton-second harmonic generation imaging, we determined that partial deproteinization of dentin increased the amount of immobilized AAMPs as compared with the total etched dentin at the dentin surface and extended deeply around dentinal tubules. Last, we analyzed the release rate of AAMPs from dentin coatings in artificial saliva to predict their stability in the clinical setting. In conclusion, priming dentin with AAMPs is a versatile new approach with potential to fortify the otherwise vulnerable adhesive-based interfaces.
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Affiliation(s)
- D G Moussa
- 1 MDRCBB-Minnesota Dental Research Center for Biomaterials and Biomechanics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA
| | - J A Kirihara
- 2 Center for Mass Spectrometry and Proteomics, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Z Ye
- 1 MDRCBB-Minnesota Dental Research Center for Biomaterials and Biomechanics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA
| | - N G Fischer
- 1 MDRCBB-Minnesota Dental Research Center for Biomaterials and Biomechanics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA
| | - J Khot
- 1 MDRCBB-Minnesota Dental Research Center for Biomaterials and Biomechanics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA
| | - B A Witthuhn
- 2 Center for Mass Spectrometry and Proteomics, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - C Aparicio
- 1 MDRCBB-Minnesota Dental Research Center for Biomaterials and Biomechanics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA
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Moussa DG, Fok A, Aparicio C. Hydrophobic and antimicrobial dentin: A peptide-based 2-tier protective system for dental resin composite restorations. Acta Biomater 2019; 88:251-265. [PMID: 30753942 PMCID: PMC6474255 DOI: 10.1016/j.actbio.2019.02.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/09/2019] [Accepted: 02/08/2019] [Indexed: 12/12/2022]
Abstract
Dental caries, i.e., tooth decay mediated by bacterial activity, is the most widespread chronic disease worldwide. Carious lesions are commonly treated using dental resin composite restorations. However, resin composite restorations are prone to recurrent caries, i.e., reinfection of the surrounding dental hard tissues. Recurrent caries is mainly a consequence of waterborne and/or biofilm-mediated degradation of the tooth-restoration interface through hydrolytic, acidic and/or enzymatic challenges. Here we use amphipathic antimicrobial peptides to directly coat dentin to provide resin composite restorations with a 2-tier protective system, simultaneously exploiting the physicochemical and biological properties of these peptides. Our peptide coatings modulate dentin's hydrophobicity, impermeabilize it, and are active against multispecies biofilms derived from caries-active individuals. Therefore, the coatings hinder water penetration along the otherwise vulnerable dentin/restoration interface, even after in vitro aging, and increase its resistance against degradation by water, acids, and saliva. Moreover, they do not weaken the resin composite restorations mechanically. The peptide-coated highly-hydrophobic dentin is expected to notably improve the service life of resin composite restorations and to enable the development of entirely hydrophobic restorative systems. The peptide coatings were also antimicrobial and thus, they provide a second tier of protection preventing re-infection of tissues in contact with restorations. STATEMENT OF SIGNIFICANCE: We present a technology using designer peptides to treat the most prevalent chronic disease worldwide; dental caries. Specifically, we used antimicrobial amphipathic peptides to coat dentin with the goal of increasing the service life of the restorative materials used to treat dental caries, which is nowadays 5 years on average. Water and waterborne agents (enzymes, acids) degrade restorative materials and enable re-infection at the dentin/restoration interface. Our peptide coatings will hinder degradation of the restoration as they produced highly hydrophobic and antimicrobial dentin/material interfaces. We anticipate a high technological and economic impact of our technology as it can notably reduce the lifelong dental bill of patients worldwide. Our findings can enable the development of restorations with all-hydrophobic and so, more protective components.
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Affiliation(s)
- Dina G Moussa
- MDRCBB-Minnesota Dental Research Center for Biomaterials and Biomechanics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA
| | - Alex Fok
- MDRCBB-Minnesota Dental Research Center for Biomaterials and Biomechanics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA
| | - Conrado Aparicio
- MDRCBB-Minnesota Dental Research Center for Biomaterials and Biomechanics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA.
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10
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Li T, Wang N, Chen S, Lu R, Li H, Zhang Z. Antibacterial activity and cytocompatibility of an implant coating consisting of TiO 2 nanotubes combined with a GL13K antimicrobial peptide. Int J Nanomedicine 2017; 12:2995-3007. [PMID: 28442908 PMCID: PMC5396942 DOI: 10.2147/ijn.s128775] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Prevention of implant-associated infections at an early stage of surgery is highly desirable for the long-term efficacy of implants in dentistry and orthopedics. Infection prophylaxis using conventional antibiotics is becoming less effective due to the development of bacteria resistant to multiple antibiotics. An ideal strategy to conquer bacterial infections is the local delivery of antibacterial agents. Therefore, antimicrobial peptide (AMP) eluting coatings on implant surfaces is a promising alternative. In this study, the feasibility of utilizing TiO2 nanotubes (TNTs), processed using anodization, as carriers to deliver a candidate AMP on titanium surfaces for the prevention of implant-associated infections is assessed. The broad-spectrum GL13K (GKIIKLKASLKLL-CONH2) AMP derived from human parotid secretory protein was selected and immobilized to TNTs using a simple soaking technique. Field emission scanning electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy, and liquid chromatography–mass spectrometry analyses confirmed the successful immobilization of GL13K to anatase TNTs. The drug-loaded coatings demonstrated a sustained and slow drug release profile in vitro and eradicated the growth of Fusobacterium nucleatum and Porphyromonas gingivalis within 5 days of culture, as assessed by disk-diffusion assay. The GL13K-immobilized TNT (GL13K-TNT) coating demonstrated greater biocompatibility, compared with a coating produced by incubating TNTs with equimolar concentrations of metronidazole. GL13K-TNTs produced no observable cytotoxicity to preosteoblastic cells (MC3T3-E1). The coating may also have an immune regulatory effect, in support of rapid osseointegration around implants. Therefore, the combination of TNTs and AMP GL13K may achieve simultaneous antimicrobial and osteoconductive activities.
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Affiliation(s)
- Tao Li
- Department of Prosthodontics, School of Stomatology, Capital Medical University.,Key Laboratory of Advanced Functional Materials, School of Materials and Engineering, Beijing University of Technology. Beijing, People's Republic of China
| | - Na Wang
- Department of Prosthodontics, School of Stomatology, Capital Medical University
| | - Su Chen
- Department of Prosthodontics, School of Stomatology, Capital Medical University
| | - Ran Lu
- Department of Prosthodontics, School of Stomatology, Capital Medical University
| | - Hongyi Li
- Key Laboratory of Advanced Functional Materials, School of Materials and Engineering, Beijing University of Technology. Beijing, People's Republic of China
| | - Zhenting Zhang
- Department of Prosthodontics, School of Stomatology, Capital Medical University
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11
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A Novel RNase 3/ECP Peptide for Pseudomonas aeruginosa Biofilm Eradication That Combines Antimicrobial, Lipopolysaccharide Binding, and Cell-Agglutinating Activities. Antimicrob Agents Chemother 2016; 60:6313-25. [PMID: 27527084 DOI: 10.1128/aac.00830-16] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/22/2016] [Indexed: 12/19/2022] Open
Abstract
Eradication of established biofilm communities of pathogenic Gram-negative species is one of the pending challenges for the development of new antimicrobial agents. In particular, Pseudomonas aeruginosa is one of the main dreaded nosocomial species, with a tendency to form organized microbial communities that offer an enhanced resistance to conventional antibiotics. We describe here an engineered antimicrobial peptide (AMP) which combines bactericidal activity with a high bacterial cell agglutination and lipopolysaccharide (LPS) affinity. The RN3(5-17P22-36) peptide is a 30-mer derived from the eosinophil cationic protein (ECP), a host defense RNase secreted by eosinophils upon infection, with a wide spectrum of antipathogen activity. The protein displays high biofilm eradication activity that is not dependent on its RNase catalytic activity, as evaluated by using an active site-defective mutant. On the other hand, the peptide encompasses both the LPS-binding and aggregation-prone regions from the parental protein, which provide the appropriate structural features for the peptide's attachment to the bacterial exopolysaccharide layer and further improved removal of established biofilms. Moreover, the peptide's high cationicity and amphipathicity promote the cell membrane destabilization action. The results are also compared side by side with other reported AMPs effective against either planktonic and/or biofilm forms of Pseudomonas aeruginosa strain PAO1. The ECP and its derived peptide are unique in combining high bactericidal potency and cell agglutination activity, achieving effective biofilm eradication at a low micromolar range. We conclude that the designed RN3(5-17P22-36) peptide is a promising lead candidate against Gram-negative biofilms.
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Spitzer P, Condic M, Herrmann M, Oberstein TJ, Scharin-Mehlmann M, Gilbert DF, Friedrich O, Grömer T, Kornhuber J, Lang R, Maler JM. Amyloidogenic amyloid-β-peptide variants induce microbial agglutination and exert antimicrobial activity. Sci Rep 2016; 6:32228. [PMID: 27624303 PMCID: PMC5021948 DOI: 10.1038/srep32228] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 08/04/2016] [Indexed: 11/09/2022] Open
Abstract
Amyloid-β (Aβ) peptides are the main components of the plaques found in the brains of patients with Alzheimer's disease. However, Aβ peptides are also detectable in secretory compartments and peripheral blood contains a complex mixture of more than 40 different modified and/or N- and C-terminally truncated Aβ peptides. Recently, anti-infective properties of Aβ peptides have been reported. Here, we investigated the interaction of Aβ peptides of different lengths with various bacterial strains and the yeast Candida albicans. The amyloidogenic peptides Aβ1-42, Aβ2-42, and Aβ3p-42 but not the non-amyloidogenic peptides Aβ1-40 and Aβ2-40 bound to microbial surfaces. As observed by immunocytochemistry, scanning electron microscopy and Gram staining, treatment of several bacterial strains and Candida albicans with Aβ peptide variants ending at position 42 (Aβx-42) caused the formation of large agglutinates. These aggregates were not detected after incubation with Aβx-40. Furthermore, Aβx-42 exerted an antimicrobial activity on all tested pathogens, killing up to 80% of microorganisms within 6 h. Aβ1-40 only had a moderate antimicrobial activity against C. albicans. Agglutination of Aβ1-42 was accelerated in the presence of microorganisms. These data demonstrate that the amyloidogenic Aβx-42 variants have antimicrobial activity and may therefore act as antimicrobial peptides in the immune system.
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Affiliation(s)
- Philipp Spitzer
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Mateja Condic
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Martin Herrmann
- Department of Medicine III, Institute for Clinical Immunology, Friedrich-Alexander-University Erlangen-Nuremberg, Gluecksstraße 4a, D-91054 Erlangen, Germany
| | - Timo Jan Oberstein
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Marina Scharin-Mehlmann
- Electron Devices, Friedrich-Alexander-University Erlangen-Nuremberg, Cauerstraße 6, D-91058 Erlangen, Germany
| | - Daniel F Gilbert
- Institute of Medical Biotechnology, Friedrich-Alexander-University Erlangen-Nuremberg, Paul-Gordan-Str. 3, D-91052 Erlangen, Germany
| | - Oliver Friedrich
- Institute of Medical Biotechnology, Friedrich-Alexander-University Erlangen-Nuremberg, Paul-Gordan-Str. 3, D-91052 Erlangen, Germany
| | - Teja Grömer
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Roland Lang
- Institute of Clinical Microbiology, Immunology and Hygiene, Friedrich-Alexander-University Erlangen-Nuremberg, Wasserturmstr. 3/5, D-91054 Erlangen, Germany
| | - Juan Manuel Maler
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
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Insights into the Antimicrobial Mechanism of Action of Human RNase6: Structural Determinants for Bacterial Cell Agglutination and Membrane Permeation. Int J Mol Sci 2016; 17:552. [PMID: 27089320 PMCID: PMC4849008 DOI: 10.3390/ijms17040552] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 03/18/2016] [Accepted: 04/05/2016] [Indexed: 12/26/2022] Open
Abstract
Human Ribonuclease 6 is a secreted protein belonging to the ribonuclease A (RNaseA) superfamily, a vertebrate specific family suggested to arise with an ancestral host defense role. Tissue distribution analysis revealed its expression in innate cell types, showing abundance in monocytes and neutrophils. Recent evidence of induction of the protein expression by bacterial infection suggested an antipathogen function in vivo. In our laboratory, the antimicrobial properties of the protein have been evaluated against Gram-negative and Gram-positive species and its mechanism of action was characterized using a membrane model. Interestingly, our results indicate that RNase6, as previously reported for RNase3, is able to specifically agglutinate Gram-negative bacteria as a main trait of its antimicrobial activity. Moreover, a side by side comparative analysis with the RN6(1-45) derived peptide highlights that the antimicrobial activity is mostly retained at the protein N-terminus. Further work by site directed mutagenesis and structural analysis has identified two residues involved in the protein antimicrobial action (Trp1 and Ile13) that are essential for the cell agglutination properties. This is the first structure-functional characterization of RNase6 antimicrobial properties, supporting its contribution to the infection focus clearance.
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Yarramaneni V, Balakrishnan D, Aparna IN, Sachdeva A, Prabhu N. Emerging Antibacterial Coated Dental Implants: A Preventive Measure for Peri-implantitis. ACTA ACUST UNITED AC 2016. [DOI: 10.5005/jp-journals-10015-1395] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
ABSTRACT
Dental implants are the modern marvel and are widely accepted as a reconstructive treatment modality for tooth replacement.
In recent times, there has been a marked progress in the clinical success rates of dental implants, but implant failures as a result of infections are continuing at an alarming rate of 8% per year, translating into 1 million failures worldwide.
Perimucositis and peri-implantitis are the chief complications reported postimplant surgery that effects its short- and long-term success. Peri-implantitis is characterized by clinical and radiological bone loss around the implant accompanied with an inflammatory reaction of the peri-implant mucosa and is an irreversible condition, whereas perimucositis is a reversible inflammatory change.
Implant surfaces provide an ideal substrate for bacterial adhesion forming a biofilm. Biofilm performs vast functions ranging from physical defensive barrier against phagocytic predation to working as a selective permeable barrier. This limits the diffusion of systemic antimicrobial agents that are capable of damaging the bacterial complexes. These rapidly growing bacteria give rise to a chronic infection which is difficult to eradicate by conventional antibiotic therapy.
To inhibit peri-implant infections, various functional modifications in the implant surfaces have been suggested. The coatings on the titanium implant are incorporated with disinfectants, antibiotics as well as antimicrobial peptides AMPs.
This paper is an attempt to review all the antibiotic coatings available for a titanium implant and discuss their prospective future to prevent peri-implant infections.
How to cite this article
Yarramaneni V, Aparna IN, Sachdeva A, Balakrishnan D, Prabhu N. Emerging Antibacterial Coated Dental Implants: A Preventive Measure for Peri-implantitis. World J Dent 2016;7(4):195-198.
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Salivary BPIFA1 (SPLUNC1) and BPIFA2 (SPLUNC2 A) are modified by head and neck cancer radiotherapy. Oral Surg Oral Med Oral Pathol Oral Radiol 2015; 119:48-58. [DOI: 10.1016/j.oooo.2014.09.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 09/16/2014] [Accepted: 09/22/2014] [Indexed: 12/11/2022]
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Holmes A, Rodrigues E, van der Wielen P, Lyons K, Haigh B, Wheeler T, Dawes P, Cannon R. Adherence ofCandida albicansto silicone is promoted by the human salivary protein SPLUNC2/PSP/BPIFA2. Mol Oral Microbiol 2014; 29:90-8. [DOI: 10.1111/omi.12048] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2014] [Indexed: 11/28/2022]
Affiliation(s)
- A.R. Holmes
- Sir John Walsh Research Institute; School of Dentistry; University of Otago; Dunedin New Zealand
| | - E. Rodrigues
- Sir John Walsh Research Institute; School of Dentistry; University of Otago; Dunedin New Zealand
| | - P. van der Wielen
- Sir John Walsh Research Institute; School of Dentistry; University of Otago; Dunedin New Zealand
| | - K.M. Lyons
- Sir John Walsh Research Institute; School of Dentistry; University of Otago; Dunedin New Zealand
| | - B.J. Haigh
- AgResearch Ltd; Ruakura Research Centre; Hamilton New Zealand
| | - T.T. Wheeler
- AgResearch Ltd; Ruakura Research Centre; Hamilton New Zealand
| | - P.J.D. Dawes
- Department of Surgical Sciences; Dunedin School of Medicine; University of Otago; Dunedin New Zealand
| | - R.D. Cannon
- Sir John Walsh Research Institute; School of Dentistry; University of Otago; Dunedin New Zealand
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Yamamoto N, Tamura A. Designing cell-aggregating peptides without cytotoxicity. Biomacromolecules 2014; 15:512-23. [PMID: 24432760 DOI: 10.1021/bm4014414] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have designed α-helical peptides de novo that can induce aggregation of various kinds of cells by focusing on physicochemical properties such as hydrophobicity, net charges, and amphipathicity. It is shown that peptide hydrophobicity is the key factor to determine capabilities for cell aggregation while peptide net charges contribute to nonspecific electrostatic interactions with cells. On the other hand, amphipathic peptides tend to exhibit cytotoxicity such as antimicrobial activity and hemolysis, which are competitive with cell-aggregation capabilities. Different from the cases of living cells, aggregation of artificial anionic liposomes appears to be mainly determined by electrostatic interactions. This discrepancy might be due to the complex structure of surfaces of cell membranes consisting of macromolecular chains such as peptidoglycans, polysaccharides, or glycocalyx, which coexist with lipid bilayers. Our design strategy would pave the way to design peptides that lead aggregation of living cells without cytotoxicity.
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Affiliation(s)
- Naoki Yamamoto
- Department of Chemistry, Graduate School of Science, Kobe University , 1-1 Rokkodai-cho, Nada, Kobe 657-8501, Japan
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Holmberg KV, Abdolhosseini M, Li Y, Chen X, Gorr SU, Aparicio C. Bio-inspired stable antimicrobial peptide coatings for dental applications. Acta Biomater 2013; 9:8224-31. [PMID: 23791670 DOI: 10.1016/j.actbio.2013.06.017] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 05/16/2013] [Accepted: 06/11/2013] [Indexed: 10/26/2022]
Abstract
We developed a novel titanium coating that has applications for preventing infection-related implant failures in dentistry and orthopedics. The coating incorporates an antimicrobial peptide, GL13K, derived from parotid secretory protein, which has been previously shown to be bactericidal and bacteriostatic in solution. We characterized the resulting physicochemical properties, resistance to degradation, activity against Porphyromonas gingivalis and in vitro cytocompatibility. Porphyromonas gingivalis is a pathogen associated with dental peri-implantitis, an inflammatory response to bacteria resulting in bone loss and implant failure. Our surface modifications obtained a homogeneous, highly hydrophobic and strongly anchored GL13K coating that was resistant to mechanical, thermochemical and enzymatic degradation. The GL13K coatings had a bactericidal effect and thus significantly reduced the number of viable bacteria compared to control surfaces. Finally, adequate proliferation of osteoblasts and human gingival fibroblasts demonstrated the GL13K coating's cytocompatibility. The robustness, antimicrobial activity and cytocompatibility of GL13K-biofunctionalized titanium make it a promising candidate for sustained inhibition of bacterial biofilm growth. This surface chemistry provides a basis for development of multifunctional bioactive surfaces to reduce patient morbidities and improve long-term clinical efficacy of metallic dental and orthopedic implants.
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Balhara V, Schmidt R, Gorr SU, DeWolf C. Membrane selectivity and biophysical studies of the antimicrobial peptide GL13K. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2193-203. [DOI: 10.1016/j.bbamem.2013.05.027] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 05/24/2013] [Accepted: 05/27/2013] [Indexed: 01/27/2023]
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Torrent M, Pulido D, Nogués MV, Boix E. Exploring new biological functions of amyloids: bacteria cell agglutination mediated by host protein aggregation. PLoS Pathog 2012; 8:e1003005. [PMID: 23133388 PMCID: PMC3486885 DOI: 10.1371/journal.ppat.1003005] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 09/17/2012] [Indexed: 01/02/2023] Open
Abstract
Antimicrobial proteins and peptides (AMPs) are important effectors of the innate immune system that play a vital role in the prevention of infections. Recent advances have highlighted the similarity between AMPs and amyloid proteins. Using the Eosinophil Cationic Protein as a model, we have rationalized the structure-activity relationships between amyloid aggregation and antimicrobial activity. Our results show how protein aggregation can induce bacteria agglutination and cell death. Using confocal and total internal reflection fluorescence microscopy we have tracked the formation in situ of protein amyloid-like aggregates at the bacteria surface and on membrane models. In both cases, fibrillar aggregates able to bind to amyloid diagnostic dyes were detected. Additionally, a single point mutation (Ile13 to Ala) can suppress the protein amyloid behavior, abolishing the agglutinating activity and impairing the antimicrobial action. The mutant is also defective in triggering both leakage and lipid vesicle aggregation. We conclude that ECP aggregation at the bacterial surface is essential for its cytotoxicity. Hence, we propose here a new prospective biological function for amyloid-like aggregates with potential biological relevance. Microbial infections are reported among the worst human diseases and cause millions of deaths per year over the world. Antibiotics are used to treat infections and have saved more lives than any other drug in human history. However, due to extended use, many strains are becoming refractive to common antibiotics. In this light, new promising compounds, like antimicrobial proteins and peptides (AMPs) are being investigated. Some AMPs also show agglutinating activity; this is the ability to clump bacteria after treatment. This feature is particularly appealing because agglutinating peptides could be used to keep bacteria to the infection focus, helping microbe clearance by host immune cells. In this study, we propose a novel mechanism to explain agglutinating activity at a molecular level using Eosinophil Cationic Protein. We show that the agglutinating mechanism is driven by the protein amyloid-like aggregation at the bacteria cell surface. Accordingly, elimination of the amyloid behavior abolishes both the agglutinating and the antimicrobial activities. This study provides a new concept on how Nature could exploit amyloid-like aggregates to fight bacterial infections. Moreover, these results could also add new insights in understanding the relation between infection and inflammation with dementia and amyloid-related diseases like Alzheimer.
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Affiliation(s)
- Marc Torrent
- Department of Biochemistry and Molecular Biology, Biosciences Faculty, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain.
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Gopal R, Seo CH, Song PI, Park Y. Effect of repetitive lysine-tryptophan motifs on the bactericidal activity of antimicrobial peptides. Amino Acids 2012; 44:645-60. [PMID: 22914980 PMCID: PMC3549253 DOI: 10.1007/s00726-012-1388-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Accepted: 08/07/2012] [Indexed: 12/19/2022]
Abstract
Previous studies identified lysine- and tryptophan-rich sequences within various cationic antimicrobial peptides. In the present study, we synthesized a series of peptides composed of lysine (K)-tryptophan (W) repeats (KW)n (where n equals 2, 3, 4 or 5) with amidation of the C-terminal to increase cationicity. We found that increases in chain length up to (KW)4 enhanced the peptides’ antibacterial activity; (KW)5 exhibited somewhat less bactericidal activity than (KW)4. Cytotoxicity, measured as lysis of human red blood cells, also increased with increasing chain length. With (KW)5, reduced antibacterial activity and increased cytotoxicity correlated with greater hydrophobicity and self-aggregation in the aqueous environment. The peptides acted by inducing rapid collapse of the bacterial transmembrane potential and induction of membrane permeability. The mode of interaction of the peptides and the phosphate groups of lipopolysaccharide was dependent upon the peptides’ ability to permeate the membrane. Longer peptides [(KW)4 and (KW)5] but not shorter peptides [(KW)2 and (KW)3] strongly bound and partially inserted into negatively charged, anionic lipid bilayers. These longer peptides also induced membrane permeabilization and aggregation of lipid vesicles. The peptides had a disordered structure in aqueous solution, and only (KW)4 and (KW)5 displayed a folded conformation on lipid membranes. Moreover, (KW)4 destroyed and agglutinated bacterial cells, demonstrating its potential as an antimicrobial agent. Collectively, the results show (KW)4 to be the most efficacious peptide in the (KW)n series, exhibiting strong antibacterial activity with little cytotoxicity.
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Affiliation(s)
- Ramamourthy Gopal
- Research Center for Proteineous Materials, Chosun University, Kwangju, South Korea
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Abdolhosseini M, Nandula SR, Song J, Hirt H, Gorr SU. Lysine substitutions convert a bacterial-agglutinating peptide into a bactericidal peptide that retains anti-lipopolysaccharide activity and low hemolytic activity. Peptides 2012; 35:231-8. [PMID: 22484285 PMCID: PMC3356437 DOI: 10.1016/j.peptides.2012.03.017] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/19/2012] [Accepted: 03/19/2012] [Indexed: 11/22/2022]
Abstract
GL13NH2 is a bacteria-agglutinating peptide derived from the sequence of the salivary protein parotid secretory protein (PSP, BPIFA2, SPLUNC2, C20orf70). The peptide agglutinates both Gram negative and Gram positive bacteria, and shows anti-lipopolysaccharide activity in vitro and in vivo. However, GL13NH2 does not exhibit bactericidal activity. To generate a more cationic peptide with potential bactericidal activity, three amino acid residues were replaced with lysine residues to generate the peptide GL13K. In this report, the antibacterial and anti-inflammatory activities of GL13K were characterized. GL13K had lost the ability to agglutinate bacteria but gained bactericidal activity. Substitution of individual amino acids in GL13K with alanine did not restore bacterial agglutination. GL13K was bactericidal against Pseudomonas aeruginosa, Streptococcus gordonii and Escherichia coli but not Porphyromonas gingivalis. Unlike the agglutinating activity of GL13NH2, the bactericidal activity of GL13K against P. aeruginosa was retained in the presence of saliva. Both GL13NH2 and GL13K exhibited anti-lipopolysaccharide activity. In GL13K, this activity appeared to depend on a serine hydroxyl group. GL13K protected mice from lipopolysaccharide-induced sepsis and the peptide exhibited a low level of hemolysis, suggesting that it may be suitable for in vivo application.
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Affiliation(s)
- Mahsa Abdolhosseini
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA.
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Song B, Zhang L, Liu XJ, Ding C, Wu LL, Gan YH, Yu GY. Proteomic analysis of secretion from human transplanted submandibular gland replacing lacrimal gland with severe keratoconjunctivitis sicca. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:550-60. [DOI: 10.1016/j.bbapap.2012.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 01/15/2012] [Accepted: 01/19/2012] [Indexed: 12/17/2022]
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Feng XL, Liu QT, Cao RB, Zhou B, Ma ZY, Deng WL, Wei JC, Qiu YF, Wang FQ, Gu JY, Wang FJ, Zheng QS, Ishag H, Chen PY. Identification and characterization of novel immunomodulatory bursal-derived pentapeptide-II (BPP-II). J Biol Chem 2011; 287:3798-807. [PMID: 22184121 DOI: 10.1074/jbc.m111.273854] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The bursa of Fabricius, the acknowledged central humoral immune organ, plays a vital role in B lymphocyte differentiation. However, there are few reports of the molecular basis of the mechanism on immune induction and potential antitumor activity of bursal-derived peptides. In this paper, a novel bursal-derived pentapeptide-II (BPP-II, MTLTG) was isolated and exerted immunomodulatory functions on antibody responses in vitro. Gene microarray analyses demonstrated that BPP-II regulated expression of 2478 genes in a mouse-derived hybridoma cell line. Immune-related gene ontology functional procedures were employed for further functional analysis. Furthermore, the majority of BPP-II-regulated pathways were associated with immune responses and tumor processes. Moreover, BPP-II exhibited immunomodulatory effects on antigen-specific immune responses in vivo, including enhancement of avian influenza virus (H9N2 subtype)-specific antibody and cytokine production and modification of T cell immunophenotypes and lymphocyte proliferation. Finally, BPP-II triggered p53 expression and stabilization and selectively inhibited tumor cell proliferation. These data identified the multifunctional factor, BPP-II, as a novel biomaterial representing an important linking between the humoral central immune system and immune induction, including antitumor. Information generated in this study elucidates further the mechanisms involved in humoral immune system and represents the potential basis of effective immunotherapeutic strategies for treating human tumors and immune improvement.
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Affiliation(s)
- Xiu-Li Feng
- Division of Key Laboratory of Animal Disease Diagnosis and Immunology, Department of Agriculture of China, Nanjing Agricultural University, Nanjing 210095, China
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Dual host-defence functions of SPLUNC2/PSP and synthetic peptides derived from the protein. Biochem Soc Trans 2011; 39:1028-32. [PMID: 21787342 DOI: 10.1042/bst0391028] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PSP (parotid secretory protein)/SPLUNC2 (short palate, lung and nasal epithelium clone 2) is expressed in human salivary glands and saliva. The protein exists as an N-glycosylated and non-glycosylated form and both appear to induce agglutination of bacteria, a major antibacterial function for salivary proteins. Both forms of PSP/SPLUNC2 bind LPS (lipopolysaccharide), suggesting that the protein may also play an anti-inflammatory role. Based on the predicted structure of PSP/SPLUNC2 and the location of known antibacterial and anti-inflammatory peptides in BPI (bactericidal/permeability-increasing protein) and LBP (LPS-binding protein), we designed GL13NH2 and GL13K, synthetic peptides that capture these proposed functions of PSP/SPLUNC2. GL13NH3 agglutinates bacteria, leading to increased clearance by macrophages and reduced spread of infection in a plant model. GL13K kills bacteria with a minimal inhibitory concentration of 5-10 μg/ml, kills bacteria in biofilm and retains activity in 150 mM NaCl and 50% saliva. Both peptides block endotoxin action, but only GL13K appears to bind endotoxin. The peptides do not cause haemolysis, haemagglutination in serum, inhibit mammalian cell proliferation or induce an inflammatory response in macrophages. These results suggest that the GL13NH2 and the modified peptide GL13K capture the biological activity of PSP/SPLUNC2 and can serve as lead compounds for the development of novel antimicrobial and anti-inflammatory peptides.
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Lorenz K, Bader M, Klaus A, Weiss W, Görg A, Hofmann T. Orosensory stimulation effects on human saliva proteome. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:10219-10231. [PMID: 21846099 DOI: 10.1021/jf2024352] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Saliva flow induced by 6-gingerol (pungent), hydroxy-α/β-sanshools (tingling), and citric acid (sour) was measured, and the time-dependent changes in the whole saliva proteome were analyzed by means of 2D-PAGE, followed by tryptic in-gel digestion and MALDI-TOF-MS peptide mass fingerprint analysis. The proteins showing significantly decreased abundance after oral 6-gingerol stimulation were identified as glutathione S-transferase P, the heat shock protein β-1, the heat shock 70 kDa protein 1, annexin A1, and cytoplasmic β-actin, whereas prolactin inducible proteins (PIP), short palate, lung and nasal epithelium carcinoma-associated protein 2 (SPLUNC2), zinc-α-2-glycoproteins (Zn-α-GP), and carbonic anhydrase VI (CAVI) were found with increased abundance. As the effects of this study were observed instantaneously upon stimulation, any proteome modulation is very likely to result from the release of proteins from preformed vesicles and not from de novo synthesis. The elevated levels of SPLUNC2, Zn-α-GP, and CAVI might be interpreted to trigger innate protective mechanisms in mucosal immunity and in nonimmune mucosal defense and might play an important role during the initial stage of inflammation.
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Affiliation(s)
- Katharina Lorenz
- Food Chemistry and Molecular Sensory Science, Technische Universität München, Lise-Meitner Strasse 34, D-85354 Freising, Germany
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Fornander L, Ghafouri B, Kihlström E, Åkerlind B, Schön T, Tagesson C, Lindahl M. Innate immunity proteins and a new truncated form of SPLUNC1 in nasopharyngeal aspirates from infants with respiratory syncytial virus infection. Proteomics Clin Appl 2011; 5:513-22. [DOI: 10.1002/prca.201100016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 06/16/2011] [Accepted: 07/11/2011] [Indexed: 11/07/2022]
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Abstract
Members of the protein family having similarity to BPI (bactericidal/permeability increasing protein) (the BPI-like proteins), also known as the PLUNC (palate, lung and nasal epithelium clone) family, have been found in a range of mammals; however, those in species other than human or mouse have been relatively little characterized. Analysis of the BPI-like proteins in cattle presents unique opportunities to investigate the function of these proteins, as well as address their evolution and contribution to the distinct physiology of ruminants. The present review summarizes the current understanding of the nature of the BPI-like locus in cattle, including the duplications giving rise to the multiple BSP30 (bovine salivary protein 30 kDa) genes from an ancestral gene in common with the single PSP (parotid secretory protein) gene found in monogastric species. Current knowledge of the expression of the BPI-like proteins in cattle is also presented, including their pattern of expression among tissues, which illustrate their independent regulation at sites of high pathogen exposure, and the abundance of the BSP30 proteins in saliva and salivary tissues. Finally, investigations of the function of the BSP30 proteins are presented, including their antimicrobial, lipopolysaccharide-binding and bacterial aggregation activities. These results are discussed in relation to hypotheses regarding the physiological role of the BPI-like proteins in cattle, including the role they may play in host defence and the unique aspects of digestion in ruminants.
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Abdolhosseini M, Sotsky JB, Shelar AP, Joyce PBM, Gorr SU. Human parotid secretory protein is a lipopolysaccharide-binding protein: identification of an anti-inflammatory peptide domain. Mol Cell Biochem 2011; 359:1-8. [PMID: 21833535 DOI: 10.1007/s11010-011-0991-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 07/06/2011] [Indexed: 12/11/2022]
Abstract
Parotid secretory protein (PSP) (C20orf70) is a salivary protein of unknown function. The protein belongs to the palate, lung, and nasal epithelium clone (PLUNC) family of mucosal secretory proteins that are predicted to be structurally similar to lipid-binding and host-defense proteins including bactericidal/permeability-increasing protein and lipopolysaccharide-binding protein. However, the PLUNC proteins exhibit significant sequence variation and different biological functions have been proposed for different family members. This study tested the functional implications of the proposed similarity of PSP to the acute phase protein lipopolysaccharide-binding protein (LBP). PSP was identified in human saliva and was soluble in 70% ethanol, as shown for other PLUNC proteins. PSP binds lipopolysaccharide and can be eluted by non-ionic detergent, but not by urea or high salt. A synthetic PSP peptide, GL13NH2, which corresponds to a lipopolysaccharide-inhibiting peptide from LBP, inhibited the binding of lipopolysaccharide to both PSP and lipopolysaccharide-binding protein. Peptides from other regions of PSP and the control peptide polymyxin B showed no effect on the binding of PSP to lipopolysaccharide. GL13NH2 also inhibited lipopolysaccharide-stimulated secretion of tumor necrosis factor from macrophages. The other PSP peptides had no effect in this assay. PSP peptides had no or only minor effect on macrophage cell viability. These results indicate that PSP is a lipopolysaccharide-binding protein that is functionally related to LBP, as suggested by their predicted structural similarities.
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Affiliation(s)
- Mahsa Abdolhosseini
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA
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Abstract
AIMS The goal of this review is to identify the antimicrobial proteins in the oral fluids, saliva and gingival crevicular fluid and identify functional families and candidates for antibacterial treatment. RESULTS Periodontal biofilms initiate a cascade of inflammatory and immune processes that lead to the destruction of gingival tissues and ultimately alveolar bone loss and tooth loss. Treatment of periodontal disease with conventional antibiotics does not appear to be effective in the absence of mechanical debridement. An alternative treatment may be found in antimicrobial peptides and proteins, which can be bactericidal and anti-inflammatory and block the inflammatory effects of bacterial toxins. The peptides have co-evolved with oral bacteria, which have not developed significant peptide resistance. Over 45 antibacterial proteins are found in human saliva and gingival crevicular fluid. The proteins and peptides belong to several different functional families and offer broad protection from invading microbes. Several antimicrobial peptides and proteins (AMPs) serve as templates for the development of therapeutic peptides and peptide mimetics, although to date none have demonstrated efficacy in human trials. CONCLUSIONS Existing and newly identified AMPs may be developed for therapeutic use in periodontal disease or can serve as templates for peptide and peptide mimetics with improved therapeutic indices.
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Affiliation(s)
- Sven-Ulrik Gorr
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA.
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31
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Nashida T, Sato R, Imai A, Shimomura H. Gene expression profiles of the three major salivary glands in rats. ACTA ACUST UNITED AC 2011; 31:387-99. [PMID: 21187650 DOI: 10.2220/biomedres.31.387] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The protein components of saliva reflect the condition of the whole body as well as the salivary glands. The aim of this study is to characterize the gene expression profiles in each of the rat major salivary glands-the parotid, submandibular, and sublingual glands. Gene expression was analyzed using DNA microarrays, and observed differences in expression of representative genes were confirmed by quantitative, real-time polymerase chain reaction. Among the glands, the contribution to the high expression of genes encoding various proteins, specifically mucin 10, proline-rich glycoproteins, proline-rich protein 2, proline-rich proteoglycans, cystatin 10, amylase, deoxyribonuclease I, and von Ebner's gland protein, was significantly greater in the parotid gland than the other glands. The submandibular and sublingual glands had similar gene expression profiles that differed from profile of the parotid gland. For example, the genes encoding mucin 19 and ovomacroglobulin were highly expressed only in the submandibular and sublingual glands. In summary, we characterized gene expression in the rat major salivary glands and provided basic information on salivary gland marker proteins.
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Affiliation(s)
- Tomoko Nashida
- Department of Biochemistry, Nippon Dental University, School of Life Dentistry at Niigata, 1-8 Hamaura-cho, Chuo-ku, Niigata, Japan.
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Torrent M, Andreu D, Nogués VM, Boix E. Connecting peptide physicochemical and antimicrobial properties by a rational prediction model. PLoS One 2011; 6:e16968. [PMID: 21347392 PMCID: PMC3036733 DOI: 10.1371/journal.pone.0016968] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 01/19/2011] [Indexed: 11/18/2022] Open
Abstract
The increasing rate in antibiotic-resistant bacterial strains has become an imperative health issue. Thus, pharmaceutical industries have focussed their efforts to find new potent, non-toxic compounds to treat bacterial infections. Antimicrobial peptides (AMPs) are promising candidates in the fight against antibiotic-resistant pathogens due to their low toxicity, broad range of activity and unspecific mechanism of action. In this context, bioinformatics' strategies can inspire the design of new peptide leads with enhanced activity. Here, we describe an artificial neural network approach, based on the AMP's physicochemical characteristics, that is able not only to identify active peptides but also to assess its antimicrobial potency. The physicochemical properties considered are directly derived from the peptide sequence and comprise a complete set of parameters that accurately describe AMPs. Most interesting, the results obtained dovetail with a model for the AMP's mechanism of action that takes into account new concepts such as peptide aggregation. Moreover, this classification system displays high accuracy and is well correlated with the experimentally reported data. All together, these results suggest that the physicochemical properties of AMPs determine its action. In addition, we conclude that sequence derived parameters are enough to characterize antimicrobial peptides.
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Affiliation(s)
- Marc Torrent
- Department of Biochemistry and Molecular Biology, Biosciences Faculty, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain.
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33
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Structural dissection and in vivo effectiveness of a peptide inhibitor of Porphyromonas gingivalis adherence to Streptococcus gordonii. Infect Immun 2010; 79:67-74. [PMID: 21041492 DOI: 10.1128/iai.00361-10] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interaction of the minor fimbrial antigen (Mfa) with streptococcal antigen I/II (e.g., SspB) facilitates colonization of the dental biofilm by Porphyromonas gingivalis. We previously showed that a 27-mer peptide derived from SspB (designated BAR) resembles the nuclear receptor (NR) box protein-protein interacting domain and potently inhibits this interaction in vitro. Here, we show that the EXXP motif upstream of the NR core α-helix contributes to the Mfa-SspB interaction and that BAR reduces P. gingivalis colonization and alveolar bone loss in vivo in a murine model of periodontitis. Substitution of Gln for Pro(1171) or Glu(1168) increased the α-helicity of BAR and reduced its inhibitory activity in vitro by 10-fold and 2-fold, respectively. To determine if BAR prevents P. gingivalis infection in vivo, mice were first infected with Streptococcus gordonii and then challenged with P. gingivalis in the absence and presence of BAR. Animals that were infected with either 10(9) CFU of S. gordonii DL-1 or 10(7) CFU of P. gingivalis 33277 did not show a statistically significant increase in alveolar bone resorption over sham-infected controls. However, infection with 10(9) CFU of S. gordonii followed by 10(7) CFU of P. gingivalis induced significantly greater bone loss (P < 0.01) than sham infection or infection of mice with either organism alone. S. gordonii-infected mice that were subsequently challenged with 10(7) CFU of P. gingivalis in the presence of BAR exhibited levels of bone resorption similar to those of sham-infected animals. Together, these results indicate that both EXXP and the NR box are important for the Mfa-SspB interaction and that BAR peptide represents a potential therapeutic that may limit colonization of the oral cavity by P. gingivalis.
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35
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Torrent M, Badia M, Moussaoui M, Sanchez D, Nogués MV, Boix E. Comparison of human RNase 3 and RNase 7 bactericidal action at the Gram-negative and Gram-positive bacterial cell wall. FEBS J 2010; 277:1713-25. [PMID: 20180804 DOI: 10.1111/j.1742-4658.2010.07595.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The eosinophil cationic protein/RNase 3 and the skin-derived RNase 7 are two human antimicrobial RNases involved in host innate immunity. Both belong to the RNase A superfamily and share a high cationicity and a common structural architecture. However, they present significant divergence at their primary structures, displaying either a high number of Arg or Lys residues, respectively. Previous comparative studies with a membrane model revealed two distinct mechanisms of action for lipid bilayer disruption. We have now compared their bactericidal activity, identifying some features that confer specificity at the bacterial cell wall level. RNase 3 displays a specific Escherichia coli cell agglutination activity, which is not shared by RNase 7. The RNase 3 agglutination process precedes the bacterial death and lysis event. In turn, RNase 7 can trigger the release of bacterial cell content without inducing any cell aggregation process. We hypothesize that the RNase 3 agglutination activity may depend on its high affinity for lipopolysaccharides and the presence of an N-terminal hydrophobic patch, and thus could facilitate host clearance activity at the infection focus by phagocytic cells. The present study suggests that the membrane disruption abilities do not solely explain the protein bacterial target preferences and highlights the key role of antimicrobial action at the bacterial cell wall level. An understanding of the interaction between antimicrobial proteins and their target at the bacterial envelope should aid in the design of alternative peptide-derived antibiotics.
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Affiliation(s)
- Marc Torrent
- Departament de Bioquímica i Biologia Molecular, Facultat Biociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
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Loit E, Hincke MT, Altosaar I. Synthetic antimicrobial peptide L8 (MHLHKTSRVTLYLL) has membrane permeabilisation and bacterial aggregation activity. Int J Antimicrob Agents 2010; 35:410-1. [PMID: 20129762 DOI: 10.1016/j.ijantimicag.2009.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 12/04/2009] [Accepted: 12/04/2009] [Indexed: 11/30/2022]
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37
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Bactericidal and membrane disruption activities of the eosinophil cationic protein are largely retained in an N-terminal fragment. Biochem J 2009; 421:425-34. [PMID: 19450231 DOI: 10.1042/bj20082330] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
ECP (eosinophil cationic protein) is an eosinophil secretion protein with antipathogen activities involved in the host immune defence system. The bactericidal capacity of ECP relies on its action on both the plasma membrane and the bacterial wall. In a search for the structural determinants of ECP antimicrobial activity, we have identified an N-terminal domain (residues 1-45) that retains most of ECP's membrane-destabilizing and antimicrobial activities. Two sections of this domain, ECP-(1-19) and ECP-(24-45), have also been evaluated. All three peptides bind and partially insert into lipid bilayers, inducing aggregation of lipid vesicles and leakage of their aqueous content. In such an environment, the peptides undergo conformational change, significantly increasing their alpha-helix content. The bactericidal activity of the three peptides against Escherichia coli and Staphylococcus aureus has been assessed at both the cytoplasmic membrane and the bacterial envelope levels. ECP-(1-45) and ECP-(24-45) partially retain the native proteins ability to bind LPS (lipopolysaccharides), and electron microscopy reveals cell damage by both peptides. Interestingly, in the E. coli cells agglutination activity of ECP is only retained by the longest segment ECP-(1-45). Comparative results suggest a task distribution, whereby residues 1-19 would contribute to membrane association and destabilization, while the 24-45 region would be essential for bactericidal action. Results also indicate that ECP cytotoxicity is not uniquely dependant on its membrane disruption capacity, and that specific interactions at the bacteria wall are also involved.
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Characterisation and expression of SPLUNC2, the human orthologue of rodent parotid secretory protein. Histochem Cell Biol 2009; 132:339-49. [PMID: 19499239 DOI: 10.1007/s00418-009-0610-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2009] [Indexed: 10/20/2022]
Abstract
We recently described the Palate Lung Nasal Clone (PLUNC) family of proteins as an extended group of proteins expressed in the upper airways, nose and mouth. Little is known about these proteins, but they are secreted into the airway and nasal lining fluids and saliva where, due to their structural similarity with lipopolysaccharide-binding protein and bactericidal/permeability-increasing protein, they may play a role in the innate immune defence. We now describe the generation and characterisation of novel affinity-purified antibodies to SPLUNC2, and use them to determine the expression of this, the major salivary gland PLUNC. Western blotting showed that the antibodies identified a number of distinct protein bands in saliva, whilst immunohistochemical analysis demonstrated protein expression in serous cells of the major salivary glands and in the ductal lumens as well as in cells of minor mucosal glands. Antibodies directed against distinct epitopes of the protein yielded different staining patterns in both minor and major salivary glands. Using RT-PCR of tissues from the oral cavity, coupled with EST analysis, we showed that the gene undergoes alternative splicing using two 5' non-coding exons, suggesting that the gene is regulated by alternative promoters. Comprehensive RACE analysis using salivary gland RNA as template failed to identify any additional exons. Analysis of saliva showed that SPLUNC2 is subject to N-glycosylation. Thus, our study shows that multiple SPLUNC2 isoforms are found in the oral cavity and suggest that these proteins may be differentially regulated in distinct tissues where they may function in the innate immune response.
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