1
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Ahirwar LK, Sharma S. Elevated levels of interleukins, leukocyte protein and cathelicidin antimicrobial peptide are strongly associated with early to mid-stage of Pythium insidiosum infection in rabbit corneas. Curr Eye Res 2022; 47:677-687. [PMID: 35179411 DOI: 10.1080/02713683.2021.2023192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
PURPOSE Corneal infection in humans caused by Pythium insidiosum can lead to blindness and the host ocular immune response to it is less studied. Herein, we investigate the expression of mediators of innate and adaptive immune responses in a rabbit model. METHODS P. insidiosum zoospores were injected intracorneally in right eye of the nine New Zealand White rabbits while left eye was injected with 1XPBS. RT-qPCR and multiplex ELISA (mELISA) were used to study the expression of antimicrobial peptides (AMPs) and immune mediators in infected cornea on 3rd, 7th and 9th day of post-infection(PI). STRING-11.0 analysis was used to predict the interactions of immune mediators. mRNA expressions of pathogen recognition receptors (PRRs) were determined in human corneal epithelial cells (HCECs) stimulated with P. insidiosum zoospores. Data was analyzed using one-way ANOVA with Post-Hoc Tukey HSD test and p-value <0.05 was considered significant. RESULTS mRNA expression assay for IL-1β, IL-6, IL-8 and Cathelicidin antimicrobial peptide (CAP)-18 showed significant upregulation (p-value <0.05) on 7thday post-infection (PI) compared to 3rd and 9thday while Leukocyte protein (LeukoP) was elevated significantly on 3rd day followed by 7th and 9th day PI . Only IL-17A among other adaptive immune cytokines showed significant upregulation on 7thday compared to 9thday PI. Expressed in pg/mL, mELISA showed significant higher levels (p-value <0.05) of IL-1β, IL-8 in infected tissue in each of the time points compared to control. STRING analysis revealed co-expression of IL-1β, IL-8 and IL-6. Among PRRs, Dectin 1 and TLR4 showed significant upregulation in HCECs at 12hrs compared to 6hrs. CONCLUSION In the rabbit P. insidiosum keratitis model, innate immune mediators: IL-1β, IL-8, IL-6, AMPs: LeukoP and CAP-18 are strongly associated in early to mid-stage of corneal infection. Dectin 1 and TLR4 were observed to be associated with recognition of P. insidiosum.
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Affiliation(s)
- Lalit Kishore Ahirwar
- Jhaveri Microbiology Centre, Brien Holden Eye Research Centre, L. V. Prasad Eye Institute, Kallam Anji Reddy Campus, L. V. Prasad Marg, Banjara Hills, Hyderabad-500034, India
| | - Savitri Sharma
- Jhaveri Microbiology Centre, Brien Holden Eye Research Centre, L. V. Prasad Eye Institute, Kallam Anji Reddy Campus, L. V. Prasad Marg, Banjara Hills, Hyderabad-500034, India
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2
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Zhu Y, Hao W, Wang X, Ouyang J, Deng X, Yu H, Wang Y. Antimicrobial peptides, conventional antibiotics, and their synergistic utility for the treatment of drug-resistant infections. Med Res Rev 2022; 42:1377-1422. [PMID: 34984699 DOI: 10.1002/med.21879] [Citation(s) in RCA: 83] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 12/09/2021] [Accepted: 12/23/2021] [Indexed: 12/13/2022]
Abstract
Antimicrobial peptides (AMPs), also known as host defense peptides (HDPs), are important effector immune defense molecules in multicellular organisms. AMPs exert their antimicrobial activities through several mechanisms; thus far, induction of drug resistance through AMPs has been regarded as unlikely. Therefore, they have great potential as new generation antimicrobial agents. To date, more than 30 AMP-related drugs are in the clinical trial phase. In recent years, studies show that some AMPs and conventional antibiotics have synergistic effects. The combined use of AMPs and antibiotics can kill drug-resistant pathogens, prevent drug resistance, and significantly improve the therapeutic effects of antibiotics. In this review, we discuss the progress in synergistic studies on AMPs and conventional antibiotics. An overview of the current understanding of the functional scope of AMPs, ongoing clinical trials, and challenges in the development processes are also presented.
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Affiliation(s)
- Yiyun Zhu
- Department of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Weijing Hao
- Department of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Xia Wang
- Department of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Jianhong Ouyang
- Department of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Xinyi Deng
- Department of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Haining Yu
- Department of Bioscience and Biotechnology, Dalian University of Technology, Dalian, Liaoning, China
| | - Yipeng Wang
- Department of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
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3
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Zhao J, Sugihara K. Analysis of PDA Dose Curves for the Extraction of Antimicrobial Peptide Properties. J Phys Chem B 2021; 125:12206-12213. [PMID: 34706534 DOI: 10.1021/acs.jpcb.1c07533] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
A mechanochromic polymer, polydiacetylene, changes color upon ligand binding, being a popular material in biosensing. However, whether it can also detect ligand functions in addition to binding is left understudied. In this work, we report that the polydiacetylene can be used to determine the net charges and the mode of actions (carpet model, toroidal pore model, etc.) of antimicrobial peptides and detergents via EC50 and Hill coefficients from the colorimetric response-dose curves. This opens a potential for high-throughput peptide screening by functions, which is difficult with the conventional methods.
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Affiliation(s)
- Jiangtao Zhao
- Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland
| | - Kaori Sugihara
- Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland.,Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba Meguro-Ku, Tokyo 153-8505, Japan
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4
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Drab E, Sugihara K. Cooperative Function of LL-37 and HNP1 Protects Mammalian Cell Membranes from Lysis. Biophys J 2020; 119:2440-2450. [PMID: 33157121 DOI: 10.1016/j.bpj.2020.10.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/08/2020] [Indexed: 01/10/2023] Open
Abstract
LL-37, cleaved from human cathelicidin, and human neutrophil peptide-1 (HNP1) from the defensin family are antimicrobial peptides that are occasionally co-released from neutrophils, which synergistically kill bacteria. We report that this couple presents another type of cooperativity against host eukaryotic cells, in which they antagonistically minimize cytotoxicity by protecting membranes from lysis. Our results describe the potential of the LL-37/HNP1 cooperativity that switches from membrane-destructive to membrane-protective functions, depending on whether the target is an enemy or a host.
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Affiliation(s)
- Ewa Drab
- Department of Physical Chemistry, University of Geneva, Geneva, Switzerland
| | - Kaori Sugihara
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan; Department of Physical Chemistry, University of Geneva, Geneva, Switzerland.
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5
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Ilyas H, Kim J, Lee D, Malmsten M, Bhunia A. Structural insights into the combinatorial effects of antimicrobial peptides reveal a role of aromatic-aromatic interactions in antibacterial synergism. J Biol Chem 2019; 294:14615-14633. [PMID: 31383740 DOI: 10.1074/jbc.ra119.009955] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/02/2019] [Indexed: 01/10/2023] Open
Abstract
The recent development of plants that overexpress antimicrobial peptides (AMPs) provides opportunities for controlling plant diseases. Because plants employ a broad-spectrum antimicrobial defense, including those based on AMPs, transgenic modification for AMP overexpression represents a potential way to utilize a defense system already present in plants. Herein, using an array of techniques and approaches, we report on VG16KRKP and KYE28, two antimicrobial peptides, which in combination exhibit synergistic antimicrobial effects against plant pathogens and are resistant against plant proteases. Investigating the structural origin of these synergistic antimicrobial effects with NMR spectroscopy of the complex formed between these two peptides and their mutated analogs, we demonstrate the formation of an unusual peptide complex, characterized by the formation of a bulky hydrophobic hub, stabilized by aromatic zippers. Using three-dimensional structure analyses of the complex in bacterial outer and inner membrane components and when bound to lipopolysaccharide (LPS) or bacterial membrane mimics, we found that this structure is key for elevating antimicrobial potency of the peptide combination. We conclude that the synergistic antimicrobial effects of VG16KRKP and KYE28 arise from the formation of a well-defined amphiphilic dimer in the presence of LPS and also in the cytoplasmic bacterial membrane environment. Together, these findings highlight a new application of solution NMR spectroscopy to solve complex structures to study peptide-peptide interactions, and they underscore the importance of structural insights for elucidating the antimicrobial effects of AMP mixtures.
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Affiliation(s)
- Humaira Ilyas
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VII (M), Kolkata 700054, India
| | - JaeWoong Kim
- Department of Fine Chemistry, Seoul National University of Science and Technology, Seoul 139743, Korea
| | - DongKuk Lee
- Department of Fine Chemistry, Seoul National University of Science and Technology, Seoul 139743, Korea
| | - Martin Malmsten
- Department of Pharmacy, Uppsala University, SE-75123 Uppsala, Sweden .,Department of Pharmacy, University of Copenhagen, DK 2100, Copenhagen, Denmark
| | - Anirban Bhunia
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VII (M), Kolkata 700054, India
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6
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Li W, O'Brien‐Simpson NM, Holden JA, Otvos L, Reynolds EC, Separovic F, Hossain MA, Wade JD. Covalent conjugation of cationic antimicrobial peptides with a β‐lactam antibiotic core. Pept Sci (Hoboken) 2018. [DOI: 10.1002/pep2.24059] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Wenyi Li
- School of ChemistryUniversity of Melbourne VIC3010 Australia
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne VIC3010 Australia
- Leibniz‐Forschungs Institut für Molekulare PharmakologieBerlin13125 Germany
| | - Neil M. O'Brien‐Simpson
- Bio21 Institute, University of Melbourne VIC3010 Australia
- Oral Health CRC, Melbourne Dental School, University of Melbourne VIC3010 Australia
| | - James A. Holden
- Bio21 Institute, University of Melbourne VIC3010 Australia
- Oral Health CRC, Melbourne Dental School, University of Melbourne VIC3010 Australia
| | - Laszlo Otvos
- OLPE LLC., AudubonPhiladelphia Pennsylvania19403
| | - Eric C. Reynolds
- Bio21 Institute, University of Melbourne VIC3010 Australia
- Oral Health CRC, Melbourne Dental School, University of Melbourne VIC3010 Australia
| | - Frances Separovic
- School of ChemistryUniversity of Melbourne VIC3010 Australia
- Bio21 Institute, University of Melbourne VIC3010 Australia
| | - Mohammed Akhter Hossain
- School of ChemistryUniversity of Melbourne VIC3010 Australia
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne VIC3010 Australia
| | - John D. Wade
- School of ChemistryUniversity of Melbourne VIC3010 Australia
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne VIC3010 Australia
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7
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Bolouri Moghaddam MR, Tonk M, Schreiber C, Salzig D, Czermak P, Vilcinskas A, Rahnamaeian M. The potential of the Galleria mellonella innate immune system is maximized by the co-presentation of diverse antimicrobial peptides. Biol Chem 2016; 397:939-45. [DOI: 10.1515/hsz-2016-0157] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 04/14/2016] [Indexed: 12/12/2022]
Abstract
Abstract
Antimicrobial peptides (AMPs) are ubiquitous components of the insect innate immune system. The model insect Galleria mellonella has at least 18 AMPs, some of which are still uncharacterized in terms of antimicrobial activity. To determine why G. mellonella secretes a repertoire of distinct AMPs following an immune challenge, we selected three different AMPs: cecropin A (CecA), gallerimycin and cobatoxin. We found that cobatoxin was active against Micrococcus luteus at a minimum inhibitory concentration (MIC) of 120 μm, but at 60 μm when co-presented with 4 μm CecA. In contrast, the MIC of gallerimycin presented alone was 60 μm and the co-presentation of CecA did not affect this value. Cobatoxin and gallerimycin were both inactive against Escherichia coli at physiological concentrations, however gallerimycin could potentiate the sublethal dose of CecA (0.25 μm) at a concentration of 30 μm resulting in 100% lethality. The ability of gallerimycin to potentiate the CecA was investigated by flow cytometry, revealing that 30 μm gallerimycin sensitized E. coli cells by inducing membrane depolarization, which intensified the otherwise negligible effects of 0.25 μm CecA. We therefore conclude that G. mellonella maximizes the potential of its innate immune response by the co-presentation of different AMPs that become more effective at lower concentrations when presented simultaneously.
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8
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Rahnamaeian M, Cytryńska M, Zdybicka-Barabas A, Dobslaff K, Wiesner J, Twyman RM, Zuchner T, Sadd BM, Regoes RR, Schmid-Hempel P, Vilcinskas A. Insect antimicrobial peptides show potentiating functional interactions against Gram-negative bacteria. Proc Biol Sci 2016; 282:20150293. [PMID: 25833860 PMCID: PMC4426631 DOI: 10.1098/rspb.2015.0293] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Antimicrobial peptides (AMPs) and proteins are important components of innate
immunity against pathogens in insects. The production of AMPs is costly owing to
resource-based trade-offs, and strategies maximizing the efficacy of AMPs at low
concentrations are therefore likely to be advantageous. Here, we show the
potentiating functional interaction of co-occurring insect AMPs (the bumblebee
linear peptides hymenoptaecin and abaecin) resulting in more potent
antimicrobial effects at low concentrations. Abaecin displayed no detectable
activity against Escherichia coli when tested alone at
concentrations of up to 200 μM, whereas hymenoptaecin affected bacterial
cell growth and viability but only at concentrations greater than 2 μM.
In combination, as little as 1.25 μM abaecin enhanced the bactericidal
effects of hymenoptaecin. To understand these potentiating functional
interactions, we investigated their mechanisms of action using atomic force
microscopy and fluorescence resonance energy transfer-based quenching assays.
Abaecin was found to reduce the minimal inhibitory concentration of
hymenoptaecin and to interact with the bacterial chaperone DnaK (an
evolutionarily conserved central organizer of the bacterial chaperone network)
when the membrane was compromised by hymenoptaecin. These naturally occurring
potentiating interactions suggest that combinations of AMPs could be used
therapeutically against Gram-negative bacterial pathogens that have acquired
resistance to common antibiotics.
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Affiliation(s)
- Mohammad Rahnamaeian
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Winchester Strasse 2, Giessen 35394, Germany
| | - Małgorzata Cytryńska
- Department of Immunobiology, Institute of Biology and Biochemistry, Maria Curie-Sklodowska University, Akademicka Street 19, Lublin 20-033, Poland
| | - Agnieszka Zdybicka-Barabas
- Department of Immunobiology, Institute of Biology and Biochemistry, Maria Curie-Sklodowska University, Akademicka Street 19, Lublin 20-033, Poland
| | - Kristin Dobslaff
- Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy and Center of Biotechnology and Biomedicine, University of Leipzig, Deutscher Platz 5, Leipzig 04103, Germany
| | - Jochen Wiesner
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Winchester Strasse 2, Giessen 35394, Germany
| | - Richard M Twyman
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Winchester Strasse 2, Giessen 35394, Germany TRM Ltd, PO Box 93, York YO43 3WE, UK
| | - Thole Zuchner
- Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy and Center of Biotechnology and Biomedicine, University of Leipzig, Deutscher Platz 5, Leipzig 04103, Germany
| | - Ben M Sadd
- School of Biological Sciences, Illinois State University, Campus Box 4120, Normal, IL 61790, USA
| | - Roland R Regoes
- ETH Zürich, Institute of Integrative Biology, ETH-Zentrum CHN, Universitätsstrasse 16, Zürich 8092, Switzerland
| | - Paul Schmid-Hempel
- ETH Zürich, Institute of Integrative Biology, ETH-Zentrum CHN, Universitätsstrasse 16, Zürich 8092, Switzerland
| | - Andreas Vilcinskas
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Winchester Strasse 2, Giessen 35394, Germany Institute of Phytopathology and Applied Zoology, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26-32, Giessen 35392, Germany
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9
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Rahnamaeian M, Cytryńska M, Zdybicka-Barabas A, Vilcinskas A. The functional interaction between abaecin and pore-forming peptides indicates a general mechanism of antibacterial potentiation. Peptides 2016; 78:17-23. [PMID: 26845197 DOI: 10.1016/j.peptides.2016.01.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 01/27/2016] [Accepted: 01/29/2016] [Indexed: 01/23/2023]
Abstract
Long-chain proline-rich antimicrobial peptides such as bumblebee abaecin show minimal activity against Gram-negative bacteria despite binding efficiently to specific intracellular targets. We recently reported that bumblebee abaecin interacts with Escherichia coli DnaK but shows negligible antibacterial activity unless it is combined with sublethal doses of the pore-forming peptide hymenoptaecin. These two bumblebee peptides are co-expressed in vivo in response to a bacterial challenge. Here we investigated whether abaecin interacts similarly with pore-forming peptides from other organisms by replacing hymenoptaecin with sublethal concentrations of cecropin A (0.3 μM) or stomoxyn (0.05 μM). We found that abaecin increased the membrane permeabilization effects of both peptides, confirming that it can reduce the minimal inhibitory concentrations of pore-forming peptides from other species. We also used atomic force microscopy to show that 20 μM abaecin combined with sublethal concentrations of cecropin A or stomoxyn causes profound structural changes to the bacterial cell surface. Our data indicate that the potentiating functional interaction between abaecin and pore-forming peptides is not restricted to specific co-expressed peptides from the same species but is likely to be a general mechanism. Combination therapies based on diverse insect-derived peptides could therefore be used to tackle bacteria that are recalcitrant to current antibiotics.
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Affiliation(s)
- Mohammad Rahnamaeian
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Winchester Strasse 2, D-35394 Giessen, Germany.
| | - Małgorzata Cytryńska
- Department of Immunobiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland
| | - Agnieszka Zdybicka-Barabas
- Department of Immunobiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland
| | - Andreas Vilcinskas
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Winchester Strasse 2, D-35394 Giessen, Germany; Institute for Insect Biotechnology, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany
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10
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Zhou ZP, Xia XY, Guo QS, Xu C. Bactericidal/permeability-increasing protein originates in both the testis and the epididymis and localizes in mouse spermatozoa. Asian J Androl 2014; 16:309-13. [PMID: 24457839 PMCID: PMC3955346 DOI: 10.4103/1008-682x.122583] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Bactericidal/permeability-increasing protein (BPI) is an endogenous antibiotic protein with activity against gram-negative bacteria. In the present study, we examined the expression of BPI in postnatal mouse testes and epididymides as well as the subcellular localization within epididymal spermatozoa. Our results showed that, BPI mRNA was expressed in testis and epididymis independently. Throughout the epididymis, the BPI protein level gradually decreased in the epididymal epithelium in a spatial manner, specialized within the cytoplasm of clear cells in the cauda part. We detected BPI proteins in intact acrosome, implying its testicular origin; on the other hand, after the acrosome reaction, BPI proteins were observed dispersed across the entire sperm head, especially enriched at the equatorial segment. Our findings suggested a dual origin of the BPI that generated both in the testis and epididymis, and associated with mouse spermatozoa. BPI protein might be involved in the dynamics modification of the sperm plasma membrane and also the fertilization process.
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Affiliation(s)
| | | | | | - Chen Xu
- Department of Histology and Embryology, Shanghai Jiao Tong University School of Medicine; Shanghai Key Laboratory of Reproductive Medicine, Shanghai, China
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11
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Miajlovic H, Smith SG. Bacterial self-defence: how Escherichia coli evades serum killing. FEMS Microbiol Lett 2014; 354:1-9. [PMID: 24617921 DOI: 10.1111/1574-6968.12419] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/04/2014] [Accepted: 03/05/2014] [Indexed: 12/19/2022] Open
Abstract
The ability to survive the bactericidal action of serum is advantageous to extraintestinal pathogenic Escherichia coli that gain access to the bloodstream. Evasion of the innate defences present in serum, including complement and antimicrobial peptides, involves multiple factors. Serum resistance mechanisms utilized by E. coli include the production of protective extracellular polysaccharide capsules and expression of factors that inhibit or interfere with the complement cascade. Recent studies have also highlighted the importance of structural integrity of the cell envelope in serum survival. These survival strategies are outlined in this review with particular attention to novel findings and recent insights into well-established resistance mechanisms.
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Affiliation(s)
- Helen Miajlovic
- Department of Clinical Microbiology, Sir Patrick Dun Research Laboratory, School of Medicine, Trinity College, Dublin, Ireland
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12
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Cassone M, Otvos Jr L. Synergy among antibacterial peptides and between peptides and small-molecule antibiotics. Expert Rev Anti Infect Ther 2014; 8:703-16. [DOI: 10.1586/eri.10.38] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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13
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Levy O, Elsbach P. Bactericidal/permeability-increasing protein in host defense and its efficacy in the treatment of bacterial sepsis. Curr Infect Dis Rep 2014; 3:407-12. [PMID: 24395478 DOI: 10.1007/s11908-007-1007-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The 55-kD bactericidal/permeability-increasing protein (BPI) is a neutrophil-derived polypeptide belonging to a family of lipid and endotoxin binding proteins. BPI is composed of two functionally distinct structural domains: a potently antibacterial and antiendotoxin ∼ 20-kD aminoterminal half, and an opsonic carboxy-terminal portion. In multiple animal models, a recombinant amino-terminal fragment of BPI (rBPI21) is nontoxic and protects against gram-negative bacteria and endotoxin. In humans, rBPI21 is also nontoxic and nonimmunogenic and has undergone phase II/III clinical trials with apparent therapeutic benefit.
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Affiliation(s)
- Ofer Levy
- Division of Infectious Diseases, Children's Hospital of Boston, 300 Longwood Avenue, 02115, Boston, MA, USA,
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14
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Zdybicka-Barabas A, Stączek S, Mak P, Skrzypiec K, Mendyk E, Cytryńska M. Synergistic action of Galleria mellonella apolipophorin III and lysozyme against Gram-negative bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1449-56. [DOI: 10.1016/j.bbamem.2013.02.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 01/14/2013] [Accepted: 02/08/2013] [Indexed: 12/14/2022]
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15
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Alexander DB, Iigo M, Yamauchi K, Suzui M, Tsuda H. Lactoferrin: an alternative view of its role in human biological fluids. Biochem Cell Biol 2012; 90:279-306. [PMID: 22553915 DOI: 10.1139/o2012-013] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Lactoferrin is a major component of biologically important mucosal fluids and of the specific granules of neutrophils. Understanding its biological function is essential for understanding neutrophil- and mucosal-mediated immunity. In this review, we reevaluate the in vivo functions of human lactoferrin (hLF) emphasizing in vivo studies and in vitro studies performed in biologically relevant fluids. We discuss the evidence in the literature that supports (or does not support) proposed roles for hLF in mucosal immunity and in neutrophil function. We argue that the current literature supports a microbiostatic role, but not a microbicidal role, for hLF in vivo. The literature also supports a role for hLF in inhibiting colonization and infection of epithelial surfaces by microorganisms and in protecting tissues from neutrophil-mediated damage. Using this information, we briefly discuss hLF in the context of the complex biological fluids in which it is found.
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Affiliation(s)
- David B Alexander
- Laboratory of Nanotoxicology Project, Nagoya City University, 3-1 Tanabedohri, Mizuho-ku, Nagoya 467-8603, Japan.
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16
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Rahnamaeian M. Antimicrobial peptides: modes of mechanism, modulation of defense responses. PLANT SIGNALING & BEHAVIOR 2011; 6:1325-32. [PMID: 21847025 PMCID: PMC3258061 DOI: 10.4161/psb.6.9.16319] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 05/21/2011] [Accepted: 05/23/2011] [Indexed: 05/20/2023]
Abstract
Complicated schemes of classical breeding and their drawbacks, environmental risks imposed by agrochemicals, decrease of arable land, and coincident escalating damages of pests and pathogens have accentuated the necessity for highly efficient measures to improve crop protection. During co-evolution of host-microbe interactions, antimicrobial peptides (AMPs) have exhibited a brilliant history in protecting host organisms against devastation by invading pathogens. Since the 1980s, a plethora of AMPs has been isolated from and characterized in different organisms. Nevertheless the AMPs expressed in plants render them more resistant to diverse pathogens, a more orchestrated approach based on knowledge of their mechanisms of action and cellular targets, structural toxic principle, and possible impact on immune system of corresponding transgenic plants will considerably improve crop protection strategies against harmful plant diseases. This review outlines the current knowledge on different modes of action of AMPs and then argues the waves of AMPs’ ectopic expression on transgenic plants’ immune system.
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Affiliation(s)
- Mohammad Rahnamaeian
- Department of Plant Biotechnology, College of Agriculture, Shahid Bahonar University, Kerman, Iran.
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Pata S, Yaraksa N, Daduang S, Temsiripong Y, Svasti J, Araki T, Thammasirirak S. Characterization of the novel antibacterial peptide Leucrocin from crocodile (Crocodylus siamensis) white blood cell extracts. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2011; 35:545-553. [PMID: 21184776 DOI: 10.1016/j.dci.2010.12.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 12/15/2010] [Accepted: 12/15/2010] [Indexed: 05/30/2023]
Abstract
Four novel antibacterial peptides, Leucrocin I-IV from Siamese crocodile white blood cell extracts were purified by reverse phase high performance liquid chromatography (RP-HPLC). Leucrocins exhibit strong antibacterial activity towards Staphylococcus epidermidis, Salmonella typhi and Vibrio cholerae. The peptides were 7-10 residues in length with different primary structure. The amino acid sequence of Leucrocin I is NGVQPKY with molecular mass around 806.99 Da and Leucrocin II is NAGSLLSGWG with molecular mass around 956.3 Da. Further, the interaction between peptides and bacterial membranes as part of their killing mechanism was studied by fluorescence and electron microscopy. The outer membrane and cytoplasmic membrane was the target of action of Leucrocins as assayed in model membrane by release of β-galactosidase due to the membrane permeabilization. Finally, the hemolytic effect was tested against human red blood cell. Leucrocin I, III and IV showed less toxicity against human red blood cells than Leucrocin II.
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Affiliation(s)
- Supawadee Pata
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
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18
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Livne L, Epand RF, Papahadjopoulos-Sternberg B, Epand RM, Mor A. OAK-based cochleates as a novel approach to overcome multidrug resistance in bacteria. FASEB J 2010. [PMID: 20720156 DOI: 10.1096/fj.10.167809] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Antibiotic resistance has become a worldwide medical problem. To find new ways of overcoming this phenomenon, we investigated the role of the membrane-active oligo-acyl-lysyl (OAK) sequence C(12)K-7α(8), in combination with essentially ineffective antibiotics. Determination of minimal inhibitory concentration (MIC) against gram-negative multidrug-resistant strains of Escherichia coli revealed combinations with sub-MIC OAK levels that acted synergistically with several antibiotics, thus lowering their MICs by several orders of magnitude. To shed light into the molecular basis for this synergism, we used both mutant strains and biochemical assays. Our results suggest that bacterial sensitization to antibiotics was derived mainly from the OAK's capacity to overcome the efflux-enhanced resistance mechanism, by promoting backdoor entry of otherwise excluded antibiotics. To facilitate simultaneous delivery of the pooled drugs to an infection site, we developed a novel OAK-based cochleate system with demonstrable stability in whole blood. To assess the potential therapeutic use of such cochleates, we performed preliminary experiments that imitate systemic treatment of neutropenic mice infected with lethal inoculums of multidrug resistance E. coli. Single-dose administration of erythromycin coencapsulated in OAK-based cochleates has decreased drug toxicity and increased therapeutic efficacy in a dose-dependent manner. Collectively, our findings suggest a potentially useful approach for fighting efflux-enhanced resistance mechanisms.
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Affiliation(s)
- L Livne
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
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19
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Livne L, Epand RF, Papahadjopoulos-Sternberg B, Epand RM, Mor A. OAK-based cochleates as a novel approach to overcome multidrug resistance in bacteria. FASEB J 2010; 24:5092-101. [PMID: 20720156 DOI: 10.1096/fj.10-167809] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Antibiotic resistance has become a worldwide medical problem. To find new ways of overcoming this phenomenon, we investigated the role of the membrane-active oligo-acyl-lysyl (OAK) sequence C(12)K-7α(8), in combination with essentially ineffective antibiotics. Determination of minimal inhibitory concentration (MIC) against gram-negative multidrug-resistant strains of Escherichia coli revealed combinations with sub-MIC OAK levels that acted synergistically with several antibiotics, thus lowering their MICs by several orders of magnitude. To shed light into the molecular basis for this synergism, we used both mutant strains and biochemical assays. Our results suggest that bacterial sensitization to antibiotics was derived mainly from the OAK's capacity to overcome the efflux-enhanced resistance mechanism, by promoting backdoor entry of otherwise excluded antibiotics. To facilitate simultaneous delivery of the pooled drugs to an infection site, we developed a novel OAK-based cochleate system with demonstrable stability in whole blood. To assess the potential therapeutic use of such cochleates, we performed preliminary experiments that imitate systemic treatment of neutropenic mice infected with lethal inoculums of multidrug resistance E. coli. Single-dose administration of erythromycin coencapsulated in OAK-based cochleates has decreased drug toxicity and increased therapeutic efficacy in a dose-dependent manner. Collectively, our findings suggest a potentially useful approach for fighting efflux-enhanced resistance mechanisms.
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Affiliation(s)
- L Livne
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
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20
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Ueno S, Kusaka K, Tamada Y, Zhang H, Minaba M, Kato Y. An enhancer peptide for membrane-disrupting antimicrobial peptides. BMC Microbiol 2010; 10:46. [PMID: 20152058 PMCID: PMC2834666 DOI: 10.1186/1471-2180-10-46] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 02/15/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND NP4P is a synthetic peptide derived from a natural, non-antimicrobial peptide fragment (pro-region of nematode cecropin P4) by substitution of all acidic amino acid residues with amides (i.e., Glu --> Gln, and Asp --> Asn). RESULTS In the presence of NP4P, some membrane-disrupting antimicrobial peptides (ASABF-alpha, polymyxin B, and nisin) killed microbes at lower concentration (e.g., 10 times lower minimum bactericidal concentration for ASABF-alpha against Staphylococcus aureus), whereas NP4P itself was not bactericidal and did not interfere with bacterial growth at CONCLUSIONS NP4P selectively enhanced the bactericidal activities of membrane-disrupting antimicrobial peptides by increasing the efficacy of membrane disruption against the cytoplasmic membrane.
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Affiliation(s)
- Satoshi Ueno
- Division of Insect Sciences, National Institute of Agrobiological Sciences, Oowashi 1-2, Tsukuba, Ibaraki 305-8634, Japan
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8572, Japan
| | - Kohtaro Kusaka
- Division of Insect Sciences, National Institute of Agrobiological Sciences, Oowashi 1-2, Tsukuba, Ibaraki 305-8634, Japan
| | - Yasushi Tamada
- Division of Insect Sciences, National Institute of Agrobiological Sciences, Oowashi 1-2, Tsukuba, Ibaraki 305-8634, Japan
| | - Hong Zhang
- Division of Insect Sciences, National Institute of Agrobiological Sciences, Oowashi 1-2, Tsukuba, Ibaraki 305-8634, Japan
| | - Masaomi Minaba
- Division of Insect Sciences, National Institute of Agrobiological Sciences, Oowashi 1-2, Tsukuba, Ibaraki 305-8634, Japan
| | - Yusuke Kato
- Division of Insect Sciences, National Institute of Agrobiological Sciences, Oowashi 1-2, Tsukuba, Ibaraki 305-8634, Japan
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21
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Canny G, Levy O. Bactericidal/permeability-increasing protein (BPI) and BPI homologs at mucosal sites. Trends Immunol 2009; 29:541-7. [PMID: 18838299 DOI: 10.1016/j.it.2008.07.012] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 07/24/2008] [Accepted: 07/28/2008] [Indexed: 12/19/2022]
Abstract
At mucosal surfaces, we must co-exist with a high density of diverse microorganisms; therefore, protection against these occurs on multiple levels. Leukocyte- and epithelial derived-antimicrobial peptides and proteins (AMPs) comprise an essential component of immune defense. These molecules possess antibacterial, antifungal and signalling properties and probably contribute to defence and maintenance of homeostasis between the host and commensal microorganisms. Among these AMPs is bactericidal/permeability-increasing protein (BPI), an antimicrobial protein with potent endotoxin-neutralising activity, and several homologs. This review explores the roles of BPI and and its homologs at the mucosal interface. Congeners of BPI are under biopharmaceutical development as novel anti-infective agents, highlighting the potential therapeutic relevance of this protein family.
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Affiliation(s)
- Geraldine Canny
- Department of Gynecology, Obstetrics and Medical Genetics, Central University Hospital of Vaud (CHUV), 1011 Lausanne, Switzerland.
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22
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Gueguen Y, Bernard R, Julie F, Paulina S, Delphine DG, Franck V, Philippe B, Evelyne B. Oyster hemocytes express a proline-rich peptide displaying synergistic antimicrobial activity with a defensin. Mol Immunol 2009; 46:516-22. [DOI: 10.1016/j.molimm.2008.07.021] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Accepted: 07/10/2008] [Indexed: 12/21/2022]
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23
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Rotem S, Mor A. Antimicrobial peptide mimics for improved therapeutic properties. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1788:1582-92. [PMID: 19028449 DOI: 10.1016/j.bbamem.2008.10.020] [Citation(s) in RCA: 203] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 10/16/2008] [Accepted: 10/21/2008] [Indexed: 01/04/2023]
Abstract
The relatively recent recognition of the major role played by antimicrobial peptides (AMPs) in sustaining an effective host response to immune challenges was greatly influenced by studies of amphibian peptides. AMPs are also widely regarded as a potential source of future antibiotics owing to a remarkable set of advantageous properties ranging from molecular simplicity to low-resistance swift-kill of a broad range of microbial cells. However, the peptide formula per se, represents less than ideal drug candidates, namely because of poor bioavailability issues, potential immunogenicity, optional toxicity and high production costs. To address these issues, synthetic peptides have been designed, reproducing the critical peptide biophysical characteristic in unnatural sequence-specific oligomers. Thus, the use of peptidomimetics to overcome the limitations inherent to peptides physical characteristics is becoming an important and promising approach for improving the therapeutic potential of AMPs. Here, we review most recent advances in the design strategies and the biophysical properties of the main classes of mimics to natural AMPs, emphasizing the importance of structure-activity relationship studies in fine-tuning of their physicochemical attributes for improved antimicrobial properties.
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Affiliation(s)
- Shahar Rotem
- Department of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Israel
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24
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Wittmann I, Schönefeld M, Aichele D, Groer G, Gessner A, Schnare M. Murine Bactericidal/Permeability-Increasing Protein Inhibits the Endotoxic Activity of Lipopolysaccharide and Gram-Negative Bacteria. THE JOURNAL OF IMMUNOLOGY 2008; 180:7546-52. [DOI: 10.4049/jimmunol.180.11.7546] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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25
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Bacteria in the intestine, helpful residents or enemies from within? Infect Immun 2008; 76:3360-73. [PMID: 18474643 DOI: 10.1128/iai.00187-08] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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26
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Zhou L, Beuerman RW, Huang L, Barathi A, Foo YH, Li SFY, Chew FT, Tan D. Proteomic analysis of rabbit tear fluid: Defensin levels after an experimental corneal wound are correlated to wound closure. Proteomics 2007; 7:3194-206. [PMID: 17676663 DOI: 10.1002/pmic.200700137] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The cornea is the major refracting optical element of the eye and therefore critical for forming a retinal image. The exposed surface of the eye is protected from pathogens by the innate immune system whose components include defensins, naturally occurring peptides with antimicrobial properties, and the physical barrier formed by the outer epithelial layer of the cornea. The proteomic approach has revealed that tear levels of defensins are correlated with the course of healing of an experimental corneal wound. Tears were collected from New Zealand White rabbits prior to (day 0) and daily for 5 days (days 1-5) following a standard unilateral 6 mm diameter corneal epithelial abrasion. Tear protein profiles obtained from wounded and contra-lateral control eyes were compared using SELDI ProteinChip technology. Peptides and proteins of interest were purified by RP-HPLC and characterized by nanoESI-MS/MS. Mass spectra of tears on post-wound day 1, revealed 13 peaks whose level decreased and five that increased. During wound healing the tear protein profile correlated with wound closure. An important finding was that the levels of rabbit defensins (NP-1 and NP-2), which were elevated after wounding returned to normal levels by the time the corneal abrasion healed. Relative quantification of NP-2 in tear fluid prior to (day 0) and after corneal wounding (days 1- 3) was determined using iTRAQ technology. A corneal wound eliminates the barrier function of innate immunity and puts the cornea at risk from microbial attack until the epithelial cells restore the surface barrier. The increased availability of defensins in the tears during healing suggests that these peptides could protect the cornea from microbial attack during a period of increased vulnerability.
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Affiliation(s)
- Lei Zhou
- Singapore Eye Research Institute, Singapore
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27
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Evidence of a bactericidal permeability increasing protein in an invertebrate, the Crassostrea gigas Cg-BPI. Proc Natl Acad Sci U S A 2007; 104:17759-64. [PMID: 17965238 DOI: 10.1073/pnas.0702281104] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A cDNA sequence with homologies to members of the LPS-binding protein and bactericidal/permeability-increasing protein (BPI) family was identified in the oyster Crassostrea gigas. The recombinant protein was found to bind LPS, to display bactericidal activity against Escherichia coli, and to increase the permeability of the bacterial cytoplasmic membrane. This indicated that it is a BPI rather than an LPS-binding protein. By in situ hybridization, the expression of the C. gigas BPI (Cg-bpi) was found to be induced in hemocytes after oyster bacterial challenge and to be constitutive in various epithelia of unchallenged oysters. Thus, Cg-bpi transcripts were detected in the epithelial cells of tissues/organs in contact with the external environment (mantle, gills, digestive tract, digestive gland diverticula, and gonad follicles). Therefore, Cg-BPI, whose expression profile and biological properties are reminiscent of mammalian BPIs, may provide a first line of defense against potential bacterial invasion. To our knowledge, this is the first characterization of a BPI in an invertebrate.
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28
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Elsbach P. Bactericidal permeability-increasing protein in host defence against gram-negative bacteria and endotoxin. CIBA FOUNDATION SYMPOSIUM 2007; 186:176-87; discussion 187-9. [PMID: 7768151 DOI: 10.1002/9780470514658.ch11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The bactericidal permeability-increasing protein (BPI) is a highly conserved host-defence molecule produced and stored by myeloid cells only and a major constituent of the primary granules of human and rabbit polymorphonuclear leukocytes. The c. 50 kDa BPI and a c. 23 kDa bioactive N-terminal fragment are cytotoxic only for Gram-negative bacteria. This target-cell specificity reflects the high affinity (apparent Kd: 1-10 nM) of BPI for the lipid A portion of lipopolysaccharide (LPS or endotoxin). Native and recombinant (r) holo-BPI and the N-terminal fragment (rBPI-23) bind with equal affinity to all forms of isolated LPS examined and inhibit the numerous biological effects of LPS in vitro (including in whole blood ex vivo) as well as in animals. Under the same conditions the antibacterial potencies of holo-BPI and rBPI-23 against Gram-negative bacteria with rough chemotype LPS (whether encapsulated or not) are also the same, but against more resistant smooth chemotype Gram-negative bacteria rBPI-23 is up to 30-fold more potent than holo-BPI. Holo-BPI and rBPI-23 protect a broad range of animals against lethal cytotoxic effects of LPS and in some cases against lethal inoculations with live Gram-negative bacteria.
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Affiliation(s)
- P Elsbach
- Department of Medicine, New York University Medical Center, New York 10016, USA
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29
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Schultz H, Weiss JP. The bactericidal/permeability-increasing protein (BPI) in infection and inflammatory disease. Clin Chim Acta 2007; 384:12-23. [PMID: 17678885 PMCID: PMC2695927 DOI: 10.1016/j.cca.2007.07.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 05/23/2007] [Accepted: 07/03/2007] [Indexed: 11/28/2022]
Abstract
Gram-negative bacteria (GNB) and their endotoxin present a constant environmental challenge. Endotoxins can potently signal mobilization of host defenses against invading GNB but also potentially induce severe pathophysiology, necessitating controlled initiation and resolution of endotoxin-induced inflammation to maintain host integrity. The bactericidal/permeability-increasing protein (BPI) is a pluripotent protein expressed, in humans, mainly neutrophils. BPI exhibits strong antimicrobial activity against GNB and potent endotoxin-neutralizing activity. BPI mobilized with neutrophils in response to invading GNB can promote intracellular and extracellular bacterial killing, endotoxin neutralization and clearance, and delivery of GNB outer membrane antigens to dendritic cells. Tissue expression by dermal fibroblasts and epithelia could further amplify local levels of BPI and local interaction with GNB and endotoxin, helping to constrain local tissue infection and inflammation and prevent systemic infection and systemic inflammation. This review article focuses on the structural and functional properties of BPI with respect to its contribution to host defense during GNB infections and endotoxin-induced inflammation and the genesis of autoantibodies against BPI that can blunt BPI activity and potentially contribute to chronic inflammatory disease.
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Affiliation(s)
- Hendrik Schultz
- Division of Infectious Diseases, University of Iowa, and Iowa City VAMC, USA, Iowa City, Iowa 52242, USA.
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30
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Xiao Y, Dai H, Bommineni YR, Soulages JL, Gong YX, Prakash O, Zhang G. Structure-activity relationships of fowlicidin-1, a cathelicidin antimicrobial peptide in chicken. FEBS J 2006; 273:2581-93. [PMID: 16817888 DOI: 10.1111/j.1742-4658.2006.05261.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cationic antimicrobial peptides are naturally occurring antibiotics that are actively being explored as a new class of anti-infective agents. We recently identified three cathelicidin antimicrobial peptides from chicken, which have potent and broad-spectrum antibacterial activities in vitro (Xiao Y, Cai Y, Bommineni YR, Fernando SC, Prakash O, Gilliland SE & Zhang G (2006) J Biol Chem281, 2858-2867). Here we report that fowlicidin-1 mainly adopts an alpha-helical conformation with a slight kink induced by glycine close to the center, in addition to a short flexible unstructured region near the N terminus. To gain further insight into the structural requirements for function, a series of truncation and substitution mutants of fowlicidin-1 were synthesized and tested separately for their antibacterial, cytolytic and lipopolysaccharide (LPS)-binding activities. The short C-terminal helical segment after the kink, consisting of a stretch of eight amino acids (residues 16-23), was shown to be critically involved in all three functions, suggesting that this region may be required for the peptide to interact with LPS and lipid membranes and to permeabilize both prokaryotic and eukaryotic cells. We also identified a second segment, comprising three amino acids (residues 5-7) in the N-terminal flexible region, that participates in LPS binding and cytotoxicity but is less important in bacterial killing. The fowlicidin-1 analog, with deletion of the second N-terminal segment (residues 5-7), was found to retain substantial antibacterial potency with a significant reduction in cytotoxicity. Such a peptide analog may have considerable potential for development as an anti-infective agent.
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Affiliation(s)
- Yanjing Xiao
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA
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31
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Canny G, Cario E, Lennartsson A, Gullberg U, Brennan C, Levy O, Colgan SP. Functional and biochemical characterization of epithelial bactericidal/permeability-increasing protein. Am J Physiol Gastrointest Liver Physiol 2006; 290:G557-67. [PMID: 16282362 DOI: 10.1152/ajpgi.00347.2005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Epithelial cells of many mucosal organs have adapted to coexist with microbes and microbial products. In general, most studies suggest that epithelial cells benefit from interactions with commensal microorganisms present at the lumenal surface. However, potentially injurious molecules found in this microenvironment also have the capacity to elicit local inflammatory responses and even systemic disease. We have recently demonstrated that epithelia cells express the anti-infective molecule bactericidal/permeability-increasing protein (BPI). Here, we extend these findings to examine molecular mechanisms of intestinal epithelial cell (IEC) BPI expression and function. Initial experiments revealed a variance of BPI mRNA and protein expression among various IEC lines. Studies of BPI promoter expression in IECs identified regulatory regions of the BPI promoter and revealed a prominent role for CCAAT/enhancer binding protein and especially Sp1/Sp3 in the basal regulation of BPI. To assess the functional significance of this protein, we generated an IEC line stably transfected with full-length BPI. We demonstrated that, whereas epithelia express markedly less BPI protein than neutrophils, epithelial BPI contributes significantly to bacterial killing and attenuating bacterial-elicted proinflammatory signals. Additional studies in murine tissue ex vivo revealed that BPI is diffusely expressed along the crypt-villous axis and that epithelial BPI levels decrease along the length of the intestine. Taken together, these data confirm the transcriptional regulation of BPI in intestinal epithelia and provide insight into the relevance of BPI as an anti-infective molecule at intestinal surfaces.
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Affiliation(s)
- Geraldine Canny
- Center for Experimental Therapeutics and Reperfusion Injury, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
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32
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Rotem S, Radzishevsky I, Inouye RT, Samore M, Mor A. Identification of antimicrobial peptide regions derived from genomic sequences of phage lysins. Peptides 2006; 27:18-26. [PMID: 16165250 DOI: 10.1016/j.peptides.2005.07.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2005] [Revised: 07/04/2005] [Accepted: 07/06/2005] [Indexed: 11/30/2022]
Abstract
This study was designed to test the possibility that antimicrobial peptides could be derived from the genomic sequences of phage lysins. Using two lysins (D3 and PhiKZ) we selected and produced two putative peptides (X and Z, respectively) believed to possess antimicrobial properties based on their physicochemical characteristics. The data presented support this hypothesis in that the peptides and various analogs displayed antibacterial activity, bacteriostatic or bactericidal, either individually or upon combination. These putative peptides are believed to act by a mechanism of action resembling that of conventional antimicrobial peptides when judged by both structural and functional criteria. Thus, the peptides are shown to have the ability to form a helical structure, to bind to model bacterial membranes and permeabilize model liposomes. They also display rapid bactericidal kinetics and their antibacterial potency is increased upon amidation. The possible relevance of these results in contributing to potency of phage lysins is discussed. Such peptides may be used to design new potent antimicrobial compounds much needed in face of the ever threatening drug resistance problems.
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Affiliation(s)
- Shahar Rotem
- Laboratory of Antimicrobial Investigation (LAPI), Department of Biotechnology & Food Engineering, Technion - Israel Institute of Technology, Haifa, Israel
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33
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Villarrubia VG, Costa LA, Díez RA. [Secreted phospholipases A2 (sPLA2): friends or foes? Are they actors in antibacterial and anti-HIV resistance?]. Med Clin (Barc) 2005; 123:749-57. [PMID: 15574291 DOI: 10.1016/s0025-7753(04)74656-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In this paper the authors update on the deletereous or beneficial roles of human and animal secretory phospholipases A2 (sPLA2). Although human sPLA2-IIA (inflammatory) was initially thought as a foe because its pathogenic implication in sepsis, multiorganic failure or other related syndromes, recent data indicates its role in in the antiinfectious host resistance. Thus, sPLA2-IIA exhibits potent bactericidal activities against gram-negative and gram-positive (in this case, together with other endogenous inflammatory factors) bacteria. Surprisingly, human sPLA-IIA does not show in vitro anti-human immunodeficiency virus (HIV) activity, whilst several sPLA2-IA isolated from bee and serpent venons do it: this is the case for crotoxin, a sPLA2-IA isolated from the venon of Crotalus durissus terrificus (sPLA2-Cdt). The mechanism for the in vitro anti-HIV activity of sPLA2-Cdt (inhibition of Gag p24) appears to be related to the ability of the drug to desestabilize ancorage (heparans) and fusion (cholesterol) receptors on HIV target cells.
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34
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Mak P, Wójcik K, Wicherek L, Suder P, Dubin A. Antibacterial hemoglobin peptides in human menstrual blood. Peptides 2004; 25:1839-47. [PMID: 15501514 DOI: 10.1016/j.peptides.2004.06.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Revised: 06/22/2004] [Accepted: 06/24/2004] [Indexed: 10/26/2022]
Abstract
This work documents that normal menstrual vaginal blood of healthy females is exceptionally rich in hemocidins--hemoglobin (Hb) fragments having bactericidal properties. The peptide fractions were isolated from the plasma of vaginal discharge of three healthy nulliparous women and subjected to identification by automatic sequencing as well as by mass spectrometry. All 44 identified peptides originate from Hb (mainly from the N-terminal part of alpha-globin) and all demonstrated differential killing activity toward Escherichia coli. The screening of antimicrobial activity was performed using two synthetic peptides identical to those found in menstrual blood. These peptides were active mainly toward Gram-negative bacteria and to a less degree toward Gram-positive bacteria. Our results confirm recent observations that Hb-derived fragments manifest pronounced antibacterial activity and suggest that these peptides help in maintaining human vaginal homeostasis during physiologic menstrual bleeding.
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Affiliation(s)
- Paweł Mak
- Department of Analytical Biochemistry, Faculty of Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387 Kraków, Poland.
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35
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Levy O. Antimicrobial proteins and peptides: anti-infective molecules of mammalian leukocytes. J Leukoc Biol 2004; 76:909-25. [PMID: 15292276 DOI: 10.1189/jlb.0604320] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Phagocytic leukocytes are a central cellular element of innate-immune defense in mammals. Over the past few decades, substantial progress has been made in defining the means by which phagocytes kill and dispose of microbes. In addition to the generation of toxic oxygen radicals and nitric oxide, leukocytes deploy a broad array of antimicrobial proteins and peptides (APP). The majority of APP includes cationic, granule-associated (poly)peptides with affinity for components of the negatively charged microbial cell wall. Over the past few years, the range of cells expressing APP and the potential roles of these agents have further expanded. Recent advances include the discovery of two novel families of mammalian APP (peptidoglycan recognition proteins and neutrophil gelatinase-associated lipocalin), that the oxygen-dependent and oxygen-independent systems are inextricably linked, that APP can be deployed in the context of novel subcellular organelles, and APP and the Toll-like receptor system interact. From a clinical perspective, congeners of several of the APP have been developed as potential therapeutic agents and have entered clinical trials with some evidence of benefit.
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Affiliation(s)
- Ofer Levy
- Department of Medicine, Division of Infectious Diseases, Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
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36
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Wang FS. Effect of antimicrobial proteins from porcine leukocytes on Staphylococcus aureus and Escherichia coli in comminuted meats. Meat Sci 2003; 65:615-21. [DOI: 10.1016/s0309-1740(02)00255-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2002] [Revised: 09/09/2002] [Accepted: 09/09/2002] [Indexed: 10/27/2022]
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Abstract
Antibacterial peptides are the effector molecules of innate immunity. Generally they contain 15-45 amino acid residues and the net charge is positive. The cecropin type of linear peptides without cysteine were found first in insects, whilst the defensin type with three disulphide bridges were found in rabbit granulocytes. Now a database stores more than 800 sequences of antibacterial peptides and proteins from the animal and plant kingdoms. Generally, each species has 15-40 peptides made from genes, which code for only one precursor. The dominating targets are bacterial membranes and the killing reaction must be faster than the growth rate of the bacteria. Some antibacterial peptides are clearly multifunctional and an attempt to predict this property from the hydrophobicity of all amino acid side chains are given. Gene structures and biosynthesis are known both in the fruit fly Drosophila and several mammals. Humans need two classes of defensins and the cathelicidin-derived linear peptide LL-37. Clinical cases show that deficiencies in these peptides give severe symptoms. Examples given are morbus Kostmann and atopic allergy. Several antibacterial peptides are being developed as drugs.
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Affiliation(s)
- H G Boman
- Microbiology and Tumor Biology Center, Karolinska Institutet, Stockholm, Sweden.
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38
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Abstract
The increasing development of bacterial resistance to traditional antibiotics has reached alarming levels, thus creating a strong need to develop new antimicrobial agents. These new antibiotics should possess novel mechanisms of action and different cellular targets compared with existing antimicrobials. Recent discoveries and isolations of so-called animal antibiotics, mostly small cationic peptides, which represent a potent branch of natural immunity, offered the possibility to acquire new and effective antibiotics of this provenance. To this date, more than 500 antibiotic peptides have been distinguished and defined. Their antimicrobial properties present new opportunities for their use as antibiotics or for construction of their more effective derivatives, but much research is still required to pave the way to their practical use. This is a survey of substances forming an armamentarium of natural immunity of mammals.
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Affiliation(s)
- P Síma
- Division of Immunology and Gnotobiology, Institute of Microbiology, Academy of Sciences of the Czech Republic, 142 20 Prague, Czechia.
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39
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Levy O, Sisson RB, Fryer HE, Goldmann D, Valore E, Ganz T, White ML, Carroll SF, Lehmann L, Guinan EC. Neutrophil defense in patients undergoing bone marrow transplantation: bactericidal/permeability-increasing protein (BPI) and defensins in graft-derived neutrophils. Transplantation 2002; 73:1522-6. [PMID: 12023636 DOI: 10.1097/00007890-200205150-00027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Even after neutrophil counts return to near normal levels, patients undergoing myeloablative chemotherapy and bone marrow transplantation (BMT) are at risk for invasive bacterial infections, raising the possibility that their neutrophil function might be impaired. To assess potential qualitative defects in neutrophil function in patients undergoing BMT, we measured neutrophil content of the antimicrobial (poly)peptides BPI and defensins. METHODS Neutrophil extracts were analyzed for content of BPI by Western blotting and ELISA and for defensin peptides by acid-urea polyacrylamide gel electrophoresis (PAGE). Antibacterial activity of neutrophil extracts was measured against Escherichia coli K1/r, a clinical isolate sensitive to synergistic killing by BPI and defensins. RESULTS Neutrophil extract BPI content on post-BMT days +20, +30, and +100 (169+/-35, 232+/-57, and 160+/-55 ng per 106 neutrophils, respectively) was similar to the neutrophil BPI content of normal controls (163+/-35 ng per 106 neutrophils). Neutrophil defensin content also did not vary during this time-span. Activity of neutrophil extracts against E. coli K1/r did not differ between BMT patients and controls. CONCLUSION At post-BMT days +20 to +100, neutrophils derived from engrafted marrow contain normal quantities of BPI and defensins. Any deficiencies of neutrophil function during this phase are not due to inadequate expression of these antimicrobial (poly)peptides but could reflect abnormalities in other aspects of neutrophil function.
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Affiliation(s)
- Ofer Levy
- Division of Infectious Diseases, General Clinical Research Center, and Medicine, Children's Hospital, Boston, Massachusetts, USA
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40
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Abstract
Innate immune mechanisms respond rapidly to bacterial infection. A key cellular component of the innate immune response is the neutrophil, whose cytoplasmic granules contain a variety of antimicrobial proteins and peptides. Among these is the bactericidal/permeability-increasing protein (BPI), a cationic 55 kDa protein whose selective anti-infective action against Gram-negative bacteria is based on its high (nM) affinity for lipopolysaccharide (LPS, or "endotoxin"). Binding of BPI to Gram-negative bacteria results in growth inhibition, serves as an opsonin that enhances phagocytosis of bacteria and inhibits bacteria-induced inflammatory responses by blocking the interaction of LPS with host pro-inflammatory pathways. Expression of BPI appears to be developmentally regulated as human newborns apparently have lower neutrophil BPI levels than adults. BPI expression has also recently been demonstrated in human epithelial cells where it appears to be inducible by endogenous anti-inflammatory lipids (lipoxins). BPI's potent anti-endotoxic activity against a broad range of Gram-negative bacterial pathogens is manifest in biological fluids and renders it an attractive template for pharmaceutical development. Indeed, rBPI(21), an active recombinant protein derived from human BPI, has proven safe in Phase I human trials, shown promise in Phase II trials and has recently completed a Phase III trial for severe meningococcaemia with apparent benefit. Identification and evaluation of additional disease entities characterised by Gram-negative bacteraemia and/or endotoxaemia as possible targets for BPI therapy continues.
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Affiliation(s)
- Ofer Levy
- Division of Infectious Diseases, Children's Hospital of Boston, MA, USA.
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41
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Zarember KA, Katz SS, Tack BF, Doukhan L, Weiss J, Elsbach P. Host defense functions of proteolytically processed and parent (unprocessed) cathelicidins of rabbit granulocytes. Infect Immun 2002; 70:569-76. [PMID: 11796584 PMCID: PMC127701 DOI: 10.1128/iai.70.2.569-576.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2001] [Revised: 09/20/2001] [Accepted: 11/05/2001] [Indexed: 11/20/2022] Open
Abstract
Members of the cathelicidin family are present in all mammals studied. Generally, these proteins contain a conserved N-terminal domain and a structurally and functionally divergent C-terminal region that expresses antibacterial or other activities when proteolytically released. Rabbit granulocytes produce CAP18, a cathelicidin that conforms to this structural and functional organization, and also 15-kDa protein isoforms (p15s) that share several key structural features with other cathelicidins but apparently do not undergo processing with release of an active peptide. To further define the importance of proteolysis in the antibacterial activities of these proteins, we have purified from granulocytes proCAP18, its C-terminal peptide (CAP18p), and two p15 isoforms to apparent homogeneity. Of these four polypeptides, only CAP18p was independently cytotoxic to encapsulated Escherichia coli (90% inhibitory concentration, approximately 600 nM) but it was approximately 50-fold less potent on a molar basis than the bactericidal/permeability-increasing protein (BPI). However, all four cathelicidin species, notably including proCAP18, exhibited antibacterial synergy with BPI, and the p15s also displayed synergy with CAP18p in the absence of BPI. Subnanomolar concentrations of proCAP18 blocked lipopolysaccharide-induced chemiluminescence of human leukocytes, showing a molar potency more than 100-fold greater than that of CAP18p ( approximately 20 nM) or BPI ( approximately 50 nM). Thus, while independent bactericidal activity of cathelicidins requires processing, other host-defense functions do not and are more potently expressed by the unprocessed protein than by the C-terminal peptide.
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Affiliation(s)
- Kol A Zarember
- Department of Microbiology, School of Medicine New York University, New York, New York 10016, USA.
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42
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Levy O, Elsbach P. Bactericidal/permeability-increasing protein in host defense and its efficacy in the treatment of bacterial sepsis. Curr Infect Dis Rep 2001. [DOI: 10.1007/bf03160475] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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43
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Giroir BP. Bactericidal/permeability-increasing protein: clinical development and potential pediatric applications. Pediatr Infect Dis J 2001; 20:885-7. [PMID: 11734769 DOI: 10.1097/00006454-200109000-00012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- B P Giroir
- Children's Medical Center of Dallas, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Giroir BP, Scannon PJ, Levin M. Bactericidal/permeability-increasing protein--lessons learned from the phase III, randomized, clinical trial of rBPI21 for adjunctive treatment of children with severe meningococcemia. Crit Care Med 2001; 29:S130-5. [PMID: 11445748 DOI: 10.1097/00003246-200107001-00039] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To review the scientific rationale for the clinical use of recombinant bactericidal permeability-increasing protein (rBPI21) and to discuss the results, implications, and lessons learned during the clinical development of rBPI21 for adjunctive treatment of children with severe meningococcemia. DATA SOURCES The published medical literature. STUDY SELECTION Of the phase I/II and phase III trials in humans, preclinical experimental studies were selected. Data from these sources are presented in the context of the authors' experiences as principal investigators in the phase I/II and/or phase III clinical trials. DATA EXTRACTION AND DATA SYNTHESIS Bactericidal permeability-increasing protein and N-terminal fragments of bactericidal permeability-increasing protein, such as rBPI21, bind and neutralize endotoxin and are potently bactericidal against both smooth and rough forms of Gram-negative bacteria, including Neisseria meningitidis. Based on these properties and compelling preclinical data indicating that administration of rBPI21 reduced mortality in several models of sepsis, we initiated clinical trials by using rBPI21 as adjunctive therapy for children with severe meningococcemia. Data from the phase III, randomized, placebo-controlled trial indicate that rBPI21 reduces clinically significant morbidities and improves the functional outcome of children with severe meningococcemia. No statistically significant benefit in mortality was demonstrated; however, because of the rare incidence of disease and the rapidity of death in this study, the trial was substantially underpowered to detect a statistically significant mortality advantage. Before the completion of the trial, the probability that the study might have been underpowered to detect a significant reduction in mortality was recognized. An attempt at selecting a previously unvalidated composite end point to increase the meaningful event rate for the primary end point proved unsuccessful. Significant improvements were seen in other prospectively defined outcome variables that suggest an overall substantial benefit of therapy with rBPI21 in children with severe meningococcemia. CONCLUSIONS As the largest therapeutic trial conducted in pediatric critical care, the phase III trial of rBPI21 demonstrates important principles that can influence the design of future trials targeting rare, life-threatening diseases.
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Affiliation(s)
- B P Giroir
- Children's Meical Center, Dallas, TX 75235, USA.
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45
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Yan H, Hancock RE. Synergistic interactions between mammalian antimicrobial defense peptides. Antimicrob Agents Chemother 2001; 45:1558-60. [PMID: 11302828 PMCID: PMC90506 DOI: 10.1128/aac.45.5.1558-1560.2001] [Citation(s) in RCA: 187] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A single animal can express several cationic antimicrobial peptides with different sequences and structures. We demonstrate that mammalian peptides from different structural classes frequently show synergy with each other and selectively show synergy with human lysozyme.
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Affiliation(s)
- H Yan
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
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46
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Abstract
The neutrophil is a critical effector cell in humoral and innate immunity and plays vital roles in phagocytosis and bacterial killing. Discussed here are the neutrophil components necessary for these processes and the diseases in which these components are either lacking or dysfunctional, illustrating that normal neutrophil function is vital for health.
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Affiliation(s)
- N D Burg
- Department of Medicine, New York University School of Medicine, New York, New York 10016, USA.
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47
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Skerlavaj B, Scocchi M, Gennaro R, Risso A, Zanetti M. Structural and functional analysis of horse cathelicidin peptides. Antimicrob Agents Chemother 2001; 45:715-22. [PMID: 11181349 PMCID: PMC90362 DOI: 10.1128/aac.45.3.715-722.2001] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cathelicidin-derived antimicrobial peptides are a component of the peptide-based host defense of neutrophils and epithelia, with a widespread distribution in mammals. We recently reported the cDNA sequences of three putative horse myeloid cathelicidins, named eCATH-1, -2, and -3. A Western analysis was performed to investigate their presence in neutrophils and processing to mature peptides. eCATH-2 and eCATH-3, but not eCATH-1, were found to be present in uncleaved forms in horse neutrophils. The corresponding mature peptides were detected in inflammatory sites, suggesting that processing of the propeptides takes place upon neutrophil activation. A functional characterization was then performed with synthetic eCATH peptides. Circular dichroism measurements indicated an amphipathic alpha-helical conformation of these peptides in an anisotropic environment, and in vitro assays revealed a potent activity and a broad spectrum of antimicrobial activity for eCATH-1 and a somewhat more restricted spectrum of activity for eCATH-2. Conversely, a strong dependence on salt concentration was observed when the activity of eCATH-3 was tested. This peptide efficiently killed bacteria and some fungal species, i.e., Cryptococcus neoformans and Rhodotorula rubra, in low-ionic-strength media, but the activity was inhibited in the presence of physiological salt medium. This behavior could be modified by modulating the amphipathicity of the molecule. In fact, the synthetic analogue LLK-eCATH-3, with a slightly modified sequence that increases the hydrophobic moment of the peptide, displayed a potent activity in physiological salt medium against the strains resistant to eCATH-3 under these conditions.
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Affiliation(s)
- B Skerlavaj
- Dipartimento di Scienze e Tecnologie Biomediche, Università di Udine, 33100 Udine, Italy
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48
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Levy O. A neutrophil-derived anti-infective molecule: bactericidal/permeability-increasing protein. Antimicrob Agents Chemother 2000; 44:2925-31. [PMID: 11036002 PMCID: PMC101582 DOI: 10.1128/aac.44.11.2925-2931.2000] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- O Levy
- Division of Infectious Disease and General Clinical Research Center, Children's Hospital, Boston, Massachusetts 02115, USA.
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49
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Abstract
AbstractThe innate immune system provides rapid and effective host defense against microbial invasion in a manner that is independent of prior exposure to a given pathogen.1 It has long been appreciated that the blood contains important elements that mediate rapid responses to infection. Thus, anatomic compartments with ample blood supply are less frequently infected and recover more readily once infected, whereas regions with poor perfusion are prone to severe infection and may require surgical débridement. Blood-borne innate immune mediators are either carried in circulating blood cells (ie, leukocytes and platelets) or in plasma after release from blood cells or on secretion by the liver.
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50
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Abstract
The innate immune system provides rapid and effective host defense against microbial invasion in a manner that is independent of prior exposure to a given pathogen.1 It has long been appreciated that the blood contains important elements that mediate rapid responses to infection. Thus, anatomic compartments with ample blood supply are less frequently infected and recover more readily once infected, whereas regions with poor perfusion are prone to severe infection and may require surgical débridement. Blood-borne innate immune mediators are either carried in circulating blood cells (ie, leukocytes and platelets) or in plasma after release from blood cells or on secretion by the liver.
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