1
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Zeng P, Wang H, Zhang P, Leung SSY. Unearthing naturally-occurring cyclic antibacterial peptides and their structural optimization strategies. Biotechnol Adv 2024; 73:108371. [PMID: 38704105 DOI: 10.1016/j.biotechadv.2024.108371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 03/08/2024] [Accepted: 04/29/2024] [Indexed: 05/06/2024]
Abstract
Natural products with antibacterial activity are highly desired globally to combat against multidrug-resistant (MDR) bacteria. Antibacterial peptide (ABP), especially cyclic ABP (CABP), is one of the abundant classes. Most of them were isolated from microbes, demonstrating excellent bactericidal effects. With the improved proteolytic stability, CABPs are normally considered to have better druggability than linear peptides. However, most clinically-used CABP-based antibiotics, such as colistin, also face the challenges of drug resistance soon after they reached the market, urgently requiring the development of next-generation succedaneums. We present here a detail review on the novel naturally-occurring CABPs discovered in the past decade and some of them are under clinical trials, exhibiting anticipated application potential. According to their chemical structures, they were broadly classified into five groups, including (i) lactam/lactone-based CABPs, (ii) cyclic lipopeptides, (iii) glycopeptides, (iv) cyclic sulfur-rich peptides and (v) multiple-modified CABPs. Their chemical structures, antibacterial spectrums and proposed mechanisms are discussed. Moreover, engineered analogs of these novel CABPs are also summarized to preliminarily analyze their structure-activity relationship. This review aims to provide a global perspective on research and development of novel CABPs to highlight the effectiveness of derivatives design in identifying promising antibacterial agents. Further research efforts in this area are believed to play important roles in fighting against the multidrug-resistance crisis.
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Affiliation(s)
- Ping Zeng
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Honglan Wang
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Pengfei Zhang
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Sharon Shui Yee Leung
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong.
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2
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Mourenza A, Ganesan R, Camarero JA. Resistance is futile: targeting multidrug-resistant bacteria with de novo Cys-rich cyclic polypeptides. RSC Chem Biol 2023; 4:722-735. [PMID: 37799576 PMCID: PMC10549238 DOI: 10.1039/d3cb00015j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 07/27/2023] [Indexed: 10/07/2023] Open
Abstract
The search for novel antimicrobial agents to combat microbial pathogens is intensifying in response to rapid drug resistance development to current antibiotic therapeutics. The use of disulfide-rich head-to-tail cyclized polypeptides as molecular frameworks for designing a new type of peptide antibiotics is gaining increasing attention among the scientific community and the pharmaceutical industry. The use of macrocyclic peptides, further constrained by the presence of several disulfide bonds, makes these peptide frameworks remarkably more stable to thermal, biological, and chemical degradation showing better activities when compared to their linear analogs. Many of these novel peptide scaffolds have been shown to have a high tolerance to sequence variability in those residues not involved in disulfide bonds, able to cross biological membranes, and efficiently target complex biomolecular interactions. Hence, these unique properties make the use of these scaffolds ideal for many biotechnological applications, including the design of novel peptide antibiotics. This article provides an overview of the new developments in the use of several disulfide-rich cyclic polypeptides, including cyclotides, θ-defensins, and sunflower trypsin inhibitor peptides, among others, in the development of novel antimicrobial peptides against multidrug-resistant bacteria.
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Affiliation(s)
- Alvaro Mourenza
- Department of Pharmacology and Pharmaceutical Sciences, Alfred E. Mann School of Pharmacy Los Angeles CA90033 USA +1-(323) 442-1417
| | - Rajasekaran Ganesan
- Department of Pharmacology and Pharmaceutical Sciences, Alfred E. Mann School of Pharmacy Los Angeles CA90033 USA +1-(323) 442-1417
| | - Julio A Camarero
- Department of Pharmacology and Pharmaceutical Sciences, Alfred E. Mann School of Pharmacy Los Angeles CA90033 USA +1-(323) 442-1417
- Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California Los Angeles CA90033 USA
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3
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Chen X, Su S, Yan Y, Yin L, Liu L. Anti- Pseudomonas aeruginosa activity of natural antimicrobial peptides when used alone or in combination with antibiotics. Front Microbiol 2023; 14:1239540. [PMID: 37731929 PMCID: PMC10508351 DOI: 10.3389/fmicb.2023.1239540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/22/2023] [Indexed: 09/22/2023] Open
Abstract
The World Health Organization has recently published a list of 12 drug-resistant bacteria that posed a significant threat to human health, and Pseudomonas aeruginosa (P. aeruginosa) was among them. In China, P. aeruginosa is a common pathogen in hospital acquired pneumonia, accounting for 16.9-22.0%. It is a ubiquitous opportunistic pathogen that can infect individuals with weakened immune systems, leading to hospital-acquired acute and systemic infections. The excessive use of antibiotics has led to the development of various mechanisms in P. aeruginosa to resist conventional drugs. Thus, there is an emergence of multidrug-resistant strains, posing a major challenge to conventional antibiotics and therapeutic approaches. Antimicrobial peptides are an integral component of host defense and have been found in many living organisms. Most antimicrobial peptides are characterized by negligible host toxicity and low resistance rates, making them become promising for use as antimicrobial products. This review particularly focuses on summarizing the inhibitory activity of natural antimicrobial peptides against P. aeruginosa planktonic cells and biofilms, as well as the drug interactions when these peptides used in combination with conventional antibiotics. Moreover, the underlying mechanism of these antimicrobial peptides against P. aeruginosa strains was mainly related to destroy the membrane structure through interacting with LPS or increasing ROS levels, or targeting cellular components, leaded to cell lysis. Hopefully, this analysis will provide valuable experimental data on developing novel compounds to combat P. aeruginosa.
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Affiliation(s)
- Xueqi Chen
- Department of Pharmacy, China-Japan Friendship Hospital, Beijing, China
| | - Shan Su
- Department of Pharmacy, The Affiliated Taian City Central Hospital of Qingdao University, Taian, China
| | - Yan Yan
- Department of Pharmacy, China-Japan Friendship Hospital, Beijing, China
| | - Limei Yin
- Department of Pharmacy, China-Japan Friendship Hospital, Beijing, China
| | - Lihong Liu
- Department of Pharmacy, China-Japan Friendship Hospital, Beijing, China
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4
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Tyler TJ, Durek T, Craik DJ. Native and Engineered Cyclic Disulfide-Rich Peptides as Drug Leads. Molecules 2023; 28:molecules28073189. [PMID: 37049950 PMCID: PMC10096437 DOI: 10.3390/molecules28073189] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 03/27/2023] [Accepted: 03/29/2023] [Indexed: 04/07/2023] Open
Abstract
Bioactive peptides are a highly abundant and diverse group of molecules that exhibit a wide range of structural and functional variation. Despite their immense therapeutic potential, bioactive peptides have been traditionally perceived as poor drug candidates, largely due to intrinsic shortcomings that reflect their endogenous heritage, i.e., short biological half-lives and poor cell permeability. In this review, we examine the utility of molecular engineering to insert bioactive sequences into constrained scaffolds with desired pharmaceutical properties. Applying lessons learnt from nature, we focus on molecular grafting of cyclic disulfide-rich scaffolds (naturally derived or engineered), shown to be intrinsically stable and amenable to sequence modifications, and their utility as privileged frameworks in drug design.
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Affiliation(s)
- Tristan J. Tyler
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Thomas Durek
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia
| | - David J. Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia
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5
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Moreno-Morales J, Guardiola S, Ballesté-Delpierre C, Giralt E, Vila J. A new synthetic protegrin as a promising peptide with antibacterial activity against MDR Gram-negative pathogens. J Antimicrob Chemother 2022; 77:3077-3085. [PMID: 35972429 DOI: 10.1093/jac/dkac284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 07/30/2022] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Protegrins are a family of natural peptides from the innate immune system of vertebrates, with broad-spectrum antimicrobial activity. However, the toxicity and haemolysis of protegrin-1 (PG-1) at low concentrations renders it useless for therapeutic application. We rationally designed PLP-3, a novel synthetic PG-1-like peptide, comprising key activity features of protegrins in a constrained bicyclic structure. Our main objective was to investigate PLP-3's activity against MDR strains of Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae and to analyse its haemolysis and cytotoxicity. METHODS Peptide synthesis was performed via solid phase and intramolecular ligation in solution, and the correct folding of the peptide was verified by circular dichroism. Antimicrobial activity was performed through broth microdilution. The test panel contained 45 bacterial strains belonging to A. baumannii, P. aeruginosa and K. pneumoniae (15 strains per species) comprising colistin-resistant and MDR strains. Cytotoxicity was assessed by XTT cell viability assays using HeLa and A549 cells and haemolysis of human erythrocytes. RESULTS PLP-3 was successfully synthesized, and its antiparallel β-sheet conformation was confirmed. Antimicrobial activity screening showed MIC90 values of 2 mg/L for A. baumannii, 16 mg/L for K. pneumoniae and 8 mg/L for P. aeruginosa. The haemolysis IC50 value was 48.53 mg/L. Cytotoxicity against human HeLa and A549 cells showed values of ca. 200 mg/L in both cell lines resulting in a 100-fold selectivity window for bacterial over human cells. CONCLUSIONS PLP-3 has potent antimicrobial activity, especially against A. baumannii, while maintaining low haemolysis and toxicity against human cell lines at antimicrobial concentrations. These characteristics make PLP-3 a promising peptide with an interesting therapeutic window.
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Affiliation(s)
| | | | - Clara Ballesté-Delpierre
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,CIBER de Enfermedades Infecciosas (CIBERINFEC), Instituto Salud Carlos III, Madrid, Spain
| | - Ernest Giralt
- IRB Barcelona, Barcelona, Spain.,Department of Inorganic and Organic Chemistry, Universitat de Barcelona, Barcelona, Spain
| | - Jordi Vila
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,CIBER de Enfermedades Infecciosas (CIBERINFEC), Instituto Salud Carlos III, Madrid, Spain.,Department of Clinical Microbiology, Hospital Clinic, Barcelona, Spain
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6
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New Antimicrobial Peptide with Two CRAC Motifs: Activity against Escherichia coli and Bacillus subtilis. Microorganisms 2022; 10:microorganisms10081538. [PMID: 36013956 PMCID: PMC9412426 DOI: 10.3390/microorganisms10081538] [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: 07/01/2022] [Revised: 07/21/2022] [Accepted: 07/27/2022] [Indexed: 02/04/2023] Open
Abstract
Due to the emergence of multiple antibiotic resistance in many pathogens, the studies on new antimicrobial peptides (AMPs) have become a priority scientific direction in fundamental and applied biology. Diverse mechanisms underlie the antibacterial action of AMPs. Among them are the effects that AMPs cause on bacterial cell membranes. In this work, we studied the antibacterial activity of a peptide named P4 with the following sequence RTKLWEMLVELGNMDKAVKLWRKLKR that was constructed from two alpha-helical fragments of the influenza virus protein M1 and containing two cholesterol-recognizing amino-acid consensus (CRAC) motifs. Previously we have shown that 50 μM of peptide P4 is toxic to cultured mouse macrophages. In the present work, we have found that peptide P4 inhibits the growth of E. coli and B. subtilis strains at concentrations that are significantly lower than the cytotoxic concentration that was found for macrophages. The half-maximal inhibitory concentration (IC50) for B. subtilis and E. coli cells were 0.07 ± 0.01 μM and 1.9 ± 0.4 μM, respectively. Scramble peptide without CRAC motifs did not inhibit the growth of E. coli cells and was not cytotoxic for macrophages but had an inhibitory effect on the growth of B. subtilis cells (IC50 0.4 ± 0.2 μM). A possible involvement of CRAC motifs and membrane sterols in the mechanism of the antimicrobial action of the P4 peptide is discussed. We assume that in the case of the Gram-negative bacterium E. coli, the mechanism of the toxic action of peptide P4 is related to the interaction of CRAC motifs with sterols that are present in the bacterial membrane, whereas in the case of the Gram-positive bacterium B. subtilis, which lacks sterols, the toxic action of peptide P4 is based on membrane permeabilization through the interaction of the peptide cationic domain and anionic lipids of the bacterial membrane. Whatever the mechanism can be, we report antimicrobial activity of the peptide P4 against the representatives of Gram-positive (B. subtilis) and Gram-negative (E. coli) bacteria.
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7
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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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8
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Zhang Z, Chen D, Lu X, Zhao R, Chen Z, Li M, Xu T, Mao Y, Yang Y, Yang Z. Directed Expression of Tracheal Antimicrobial Peptide as a Treatment for Bovine-Associated Staphylococcus Aureus-Induced Mastitis in Mice. Front Vet Sci 2021; 8:700930. [PMID: 34671659 PMCID: PMC8520960 DOI: 10.3389/fvets.2021.700930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 08/24/2021] [Indexed: 11/13/2022] Open
Abstract
Bovine mastitis is perplexing the dairy industry since the initiation of intensive dairy farming, which has caused a reduction in the productivity of cows and an escalation in costs. The use of antibiotics causes a series of problems, especially the formation of bacterial antimicrobial resistance. However, there are limited antibiotic-free therapeutic strategies that can effectively relieve bacterial infection of bovine mammary glands. Hence, in this study, we constructed a mammary gland tissue-specific expression vector carrying the antimicrobial peptide of bovine-derived tracheal antimicrobial peptide (TAP) and evaluated it in both primary bovine mammary epithelial cells (pBMECs) and mice. The results showed that the vector driven by the β-lactoglobulin gene (BLG) promoter could efficiently direct the expression of TAP in pBMECs and the mammary gland tissue of mice. In addition, significant antibacterial effects were observed in both in vitro and in vivo experiments when introducing this vector to bovine-associated Staphylococcus aureus-treated pBMECs and mice, respectively. This study demonstrated that the mammary gland tissue-specific expression vector could be used to introduce antimicrobial peptide both in in vitro and in vivo and will provide a new therapeutic strategy in the treatment of bovine mastitis.
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Affiliation(s)
- Zhipeng Zhang
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Daijie Chen
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Xubin Lu
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Ruifeng Zhao
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Zhi Chen
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture & Agri-Product Safety, Ministry of Education, Yangzhou University, Yangzhou, China
| | - Mingxun Li
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Tianle Xu
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture & Agri-Product Safety, Ministry of Education, Yangzhou University, Yangzhou, China
| | - Yongjiang Mao
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Yi Yang
- Joint International Research Laboratory of Agriculture & Agri-Product Safety, Ministry of Education, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Zhangping Yang
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture & Agri-Product Safety, Ministry of Education, Yangzhou University, Yangzhou, China
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9
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Li W, Jiang YX, Chen QY, Wang GG. Recombinant fusion protein by lysozyme and antibacterial peptide enhances ischemic wound healing via angiogenesis and reduction of inflammation in diabetic db/db mice. PeerJ 2021; 9:e11256. [PMID: 33959422 PMCID: PMC8054754 DOI: 10.7717/peerj.11256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 03/21/2021] [Indexed: 01/11/2023] Open
Abstract
Background & aims Lysozyme and antibacterial peptides have been reported to broad-spectrum antibacterial activity and can further improve wound healing. The aim of this study was to assess the effectiveness of a recombinant fusion protein created by combining lysozyme and an antibacterial peptide in forming new vessels and wound healing in an ischemic hind limb. Methods An ischemic hind limb model was established by isolation and ligation of the femoral artery in diabetic db/db mice. Cutaneous wounds were created with or without ischemia. Adductor muscles and wounds were treated with or without the fusion protein. Results The fusion protein accelerated ischemic diabetic wound healing and attenuated impairment of ischemic adductor muscle . Further, the fusion protein elevated expression of platelet derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) protein and mRNA in ischemic adductor muscle, reduced levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in serum and expression of phosphorylated nuclear factor κB (p-NF-κB) and p-IKB α in ischemic adductor. The fusion protein also enhanced levels of phosphorylated VEGF and PDGF receptors in the ischemic adductor muscles from diabetic db/db mice. Conclusion The data showed that the beneficial effects of the fusion protein on ischemic wound healing may be associated with angiogenesis and reduction of inflammatory response in the ischemic adductor muscles of diabetic db/db mice.
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Affiliation(s)
- Wei Li
- Department of Pathophysiology, School of Basic Medicine, Wannan Medical College, Wuhu, Anhui, China
| | - Yu-Xin Jiang
- Department of Basic Medicine, School of Medicine, Jiaxing University, Jiaxing, Zhejiang, China
| | - Qing-Ying Chen
- Department of Integrated traditional and western medicine, General Hospital of Jinan Military Command, Jinan, Shandong, China
| | - Guo-Guang Wang
- Department of Pathophysiology, School of Basic Medicine, Wannan Medical College, Wuhu, Anhui, China
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10
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Toledo EB, Lucas DR, Simão TLBV, Calixto SD, Lassounskaia E, Muzitano MF, Damica FZ, Gomes VM, de Oliveira Carvalho A. Design of improved synthetic antifungal peptides with targeted variations in charge, hydrophobicity and chirality based on a correlation study between biological activity and primary structure of plant defensin γ-cores. Amino Acids 2021; 53:219-237. [PMID: 33483849 DOI: 10.1007/s00726-020-02929-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/07/2020] [Indexed: 12/30/2022]
Abstract
Microbial resistance to available drugs is a growing health threat imposing the need for the development of new drugs. The scaffold of plant defensins, including their γ-cores, are particularly good candidates for drug design. This work aimed to improve the antifungal activity of a previous design peptide, named A36,42,44γ32-46VuDef (for short DD) against yeasts by altering its biochemical parameters. We explore the correlation of the biological activity and structure of plant defensins and compared their primary structures by superimposition with VuDef1 and DD which indicated us the favorable position and the amino acid to be changed. Three new peptides with modifications in charge, hydrophobicity (RR and WR) and chirality (D-RR) were designed and tested against pathogenic yeasts. Inhibition was determined by absorbance. Viability of mammalian cells was determined by MTT. The three designed peptides had better inhibitory activity against the yeasts with better potency and spectrum of yeast species inhibition, with low toxicity to mammalian cells. WR, the most hydrophobic and cationic, exhibited better antifungal activity and lower toxicity. Our study provides experimental evidence that targeted changes in the primary structure of peptides based on plant defensins γ-core primary structures prove to be a good tool for the synthesis of new compounds that may be useful as alternative antifungal drugs. The method described did not have the drawback of synthesis of several peptides, because alterations are guided. When compared to other methods, the design process described is efficient and viable to those with scarce resources.
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Affiliation(s)
- Estefany Braz Toledo
- Laboratório de Fisiologia e Bioquímica de Microrganismos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Av. Alberto Lamego, nº 2000, Campos dos Goytacazes, RJ, CEP 28013-602, Brazil
| | - Douglas Ribeiro Lucas
- Laboratório de Fisiologia e Bioquímica de Microrganismos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Av. Alberto Lamego, nº 2000, Campos dos Goytacazes, RJ, CEP 28013-602, Brazil
| | - Thatiana Lopes Biá Ventura Simão
- Laboratório de Biologia do Reconhecer, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, 28013-602, Brazil
| | - Sanderson Dias Calixto
- Laboratório de Biologia do Reconhecer, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, 28013-602, Brazil
| | - Elena Lassounskaia
- Laboratório de Biologia do Reconhecer, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, 28013-602, Brazil
| | - Michele Frazão Muzitano
- Laboratório de Produtos Bioativos, Curso de Farmácia, Universidade Federal do Rio de Janeiro, Campus Macaé, Pólo Novo Cavaleiro-IMMT, Macaé, RJ, 27933-378, Brazil
| | - Filipe Zanirati Damica
- Laboratório de Fisiologia e Bioquímica de Microrganismos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Av. Alberto Lamego, nº 2000, Campos dos Goytacazes, RJ, CEP 28013-602, Brazil
| | - Valdirene Moreira Gomes
- Laboratório de Fisiologia e Bioquímica de Microrganismos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Av. Alberto Lamego, nº 2000, Campos dos Goytacazes, RJ, CEP 28013-602, Brazil
| | - André de Oliveira Carvalho
- Laboratório de Fisiologia e Bioquímica de Microrganismos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Av. Alberto Lamego, nº 2000, Campos dos Goytacazes, RJ, CEP 28013-602, Brazil.
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11
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Liu Y, Shi J, Tong Z, Jia Y, Yang B, Wang Z. The revitalization of antimicrobial peptides in the resistance era. Pharmacol Res 2020; 163:105276. [PMID: 33161137 DOI: 10.1016/j.phrs.2020.105276] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 01/14/2023]
Abstract
The antibiotic resistance crisis is becoming incredibly thorny due to the indiscriminate employment of antibiotics in agriculture and aquaculture, such as growth promoters, and the emergence of bacteria that are capable of enduring antibiotic treatment in an endless stream. Hence, to reverse this situation, vigorous efforts should be made in the process of identifying other alternative strategies with a lower frequency of resistance. Antimicrobial peptides (AMPs), originated from host defense peptides, are generally produced by a variety of organisms as defensive weapons to protect the host from other pathogenic bacteria. The unique ability of AMPs to control bacterial infections, as well as low propensity to acquire resistance, provides the basis for it to become one of the promising antibacterial substances. Herein, we present new insights into the biological functions, structural properties, distinct mechanisms of action of AMPs and their resistance determinants. Besides, we separately discuss natural and synthetic AMPs, including their source, screening pathway and antibacterial activity. Lastly, challenges and perspectives to identify novel potent AMPs are highlighted, which will expand our understanding of the chemical space of antimicrobials and provide a pipeline for discovering the next-generation of AMPs.
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Affiliation(s)
- Yuan Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China; Institute of Comparative Medicine, Yangzhou University, Yangzhou, 225009, China.
| | - Jingru Shi
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, China
| | - Ziwen Tong
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, China
| | - Yuqian Jia
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, China
| | - Bingqing Yang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, China
| | - Zhiqiang Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China.
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12
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Moo CL, Yang SK, Yusoff K, Ajat M, Thomas W, Abushelaibi A, Lim SHE, Lai KS. Mechanisms of Antimicrobial Resistance (AMR) and Alternative Approaches to Overcome AMR. Curr Drug Discov Technol 2020; 17:430-447. [PMID: 30836923 DOI: 10.2174/1570163816666190304122219] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 01/30/2019] [Accepted: 01/30/2019] [Indexed: 01/21/2023]
Abstract
Antimicrobials are useful compounds intended to eradicate or stop the growth of harmful microorganisms. The sustained increase in the rates of antimicrobial resistance (AMR) worldwide is worrying and poses a major public health threat. The development of new antimicrobial agents is one of the critical approaches to overcome AMR. However, in the race towards developing alternative approaches to combat AMR, it appears that the scientific community is falling behind when pitched against the evolutionary capacity of multi-drug resistant (MDR) bacteria. Although the "pioneering strategy" of discovering completely new drugs is a rational approach, the time and effort taken are considerable, the process of drug development could instead be expedited if efforts were concentrated on enhancing the efficacy of existing antimicrobials through: combination therapies; bacteriophage therapy; antimicrobial adjuvants therapy or the application of nanotechnology. This review will briefly detail the causes and mechanisms of AMR as background, and then provide insights into a novel, future emerging or evolving strategies that are currently being evaluated and which may be developed in the future to tackle the progression of AMR.
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Affiliation(s)
- Chew-Li Moo
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Shun-Kai Yang
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Khatijah Yusoff
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Mokrish Ajat
- Department of Veterinary Pre Clinical Sciences, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
| | - Warren Thomas
- Perdana University-Royal College of Surgeons in Ireland School of Medicine, Perdana University, MAEPS Building, Serdang, Selangor, Malaysia
| | - Aisha Abushelaibi
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, 41012 Abu Dhabi, United Arab Emirates
| | - Swee-Hua-Erin Lim
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, 41012 Abu Dhabi, United Arab Emirates
| | - Kok-Song Lai
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
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Elucidation of structural and functional integration of a novel antimicrobial peptide from Antheraea mylitta. Bioorg Med Chem Lett 2017; 27:1686-1692. [DOI: 10.1016/j.bmcl.2017.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 02/22/2017] [Accepted: 03/02/2017] [Indexed: 01/09/2023]
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14
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Panteleev PV, Myshkin MY, Shenkarev ZO, Ovchinnikova TV. Dimerization of the antimicrobial peptide arenicin plays a key role in the cytotoxicity but not in the antibacterial activity. Biochem Biophys Res Commun 2016; 482:1320-1326. [PMID: 27940358 DOI: 10.1016/j.bbrc.2016.12.035] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 12/06/2016] [Indexed: 12/11/2022]
Abstract
The β-hairpin antimicrobial peptides arenicins from marine polychaeta Arenicola marina exhibit a broad spectrum of antimicrobial activity and high cytotoxicity. In this study the biological activities of arenicin-1 and its therapeutically valuable analog Ar-1[V8R] were investigated. The peptide Ar-1[V8R] displays significantly reduced cytotoxicity against mammalian cells relative to the wild-type arenicin-1. At the same time, both peptides exhibit similar antibacterial activities and kinetics of bacterial membrane permeabilization. Comparative NMR analysis of the peptides spatial structures in water and membrane-mimicking environment showed that Ar-1[V8R] in contrast to arenicin has significantly lower dimerization propensity. Thus, dimerization of the antimicrobial peptide arenicin plays a key role in the cytotoxicity but not in the antibacterial activity.
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Affiliation(s)
- Pavel V Panteleev
- M.M.Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow, Russia
| | - Mikhail Yu Myshkin
- M.M.Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow, Russia
| | - Zakhar O Shenkarev
- M.M.Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow, Russia
| | - Tatiana V Ovchinnikova
- M.M.Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow, Russia.
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15
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Omardien S, Brul S, Zaat SAJ. Antimicrobial Activity of Cationic Antimicrobial Peptides against Gram-Positives: Current Progress Made in Understanding the Mode of Action and the Response of Bacteria. Front Cell Dev Biol 2016; 4:111. [PMID: 27790614 PMCID: PMC5063857 DOI: 10.3389/fcell.2016.00111] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 09/21/2016] [Indexed: 01/11/2023] Open
Abstract
Antimicrobial peptides (AMPs) have been proposed as a novel class of antimicrobials that could aid the fight against antibiotic resistant bacteria. The mode of action of AMPs as acting on the bacterial cytoplasmic membrane has often been presented as an enigma and there are doubts whether the membrane is the sole target of AMPs. Progress has been made in clarifying the possible targets of these peptides, which is reported in this review with as focus gram-positive vegetative cells and spores. Numerical estimates are discussed to evaluate the possibility that targets, other than the membrane, could play a role in susceptibility to AMPs. Concerns about possible resistance that bacteria might develop to AMPs are addressed. Proteomics, transcriptomics, and other molecular techniques are reviewed in the context of explaining the response of bacteria to the presence of AMPs and to predict what resistance strategies might be. Emergent mechanisms are cell envelope stress responses as well as enzymes able to degrade and/or specifically bind (and thus inactivate) AMPs. Further studies are needed to address the broadness of the AMP resistance and stress responses observed.
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Affiliation(s)
- Soraya Omardien
- Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam, Netherlands
| | - Stanley Brul
- Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam, Netherlands
| | - Sebastian A J Zaat
- Department of Medical Microbiology, Center for Infection and Immunity Amsterdam, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
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16
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Battersby AJ, Khara J, Wright VJ, Levy O, Kampmann B. Antimicrobial Proteins and Peptides in Early Life: Ontogeny and Translational Opportunities. Front Immunol 2016; 7:309. [PMID: 27588020 PMCID: PMC4989132 DOI: 10.3389/fimmu.2016.00309] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 07/29/2016] [Indexed: 12/18/2022] Open
Abstract
While developing adaptive immune responses, young infants are especially vulnerable to serious infections, including sepsis, meningitis, and pneumonia. Antimicrobial proteins and peptides (APPs) are key effectors that function as broad-spectrum anti-infectives. This review seeks to summarize the clinically relevant functional qualities of APPs and the increasing clinical trial evidence for their use to combat serious infections in infancy. Levels of APPs are relatively low in early life, especially in infants born preterm or with low birth weight (LBW). There are several rationales for the potential clinical utility of APPs in the prevention and treatment of infections in infants: (a) APPs may be most helpful in those with reduced levels; (b) during sepsis microbial products signal via pattern recognition receptors causing potentially harmful inflammation that APPs may counteract; and (c) in the era of antibiotic resistance, development of new anti-infective strategies is essential. Evidence supports the potential clinical utility of exogenous APPs to reduce infection-related morbidity in infancy. Further studies should characterize the ontogeny of antimicrobial activity in mucosal and systemic compartments, and examine the efficacy of exogenous-APP formulations to inform translational development of APPs for infant groups.
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Affiliation(s)
- Anna J Battersby
- Academic Paediatrics, Imperial College London, London, UK; Medical Research Council (MRC) Unit, Vaccines and Immunity Theme, Fajara, Gambia
| | - Jasmeet Khara
- Academic Paediatrics, Imperial College London, London, UK; Department of Pharmacy, National University of Singapore, Singapore
| | | | - Ofer Levy
- Precision Vaccines Program, Department of Medicine, Division of Infectious Diseases, Boston Children's Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Beate Kampmann
- Academic Paediatrics, Imperial College London, London, UK; Medical Research Council (MRC) Unit, Vaccines and Immunity Theme, Fajara, Gambia
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17
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AtomicChargeCalculator: interactive web-based calculation of atomic charges in large biomolecular complexes and drug-like molecules. J Cheminform 2015; 7:50. [PMID: 26500704 PMCID: PMC4613891 DOI: 10.1186/s13321-015-0099-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 10/08/2015] [Indexed: 01/24/2023] Open
Abstract
Background Partial atomic charges are a well-established concept, useful in understanding and modeling the chemical behavior of molecules, from simple compounds, to large biomolecular complexes with many reactive sites. Results This paper introduces AtomicChargeCalculator (ACC), a web-based application for the calculation and analysis of atomic charges which respond to changes in molecular conformation and chemical environment. ACC relies on an empirical
method to rapidly compute atomic charges with accuracy comparable to quantum mechanical approaches. Due to its efficient implementation, ACC can handle any type of molecular system, regardless of size and chemical complexity, from drug-like molecules to biomacromolecular complexes with hundreds of thousands of atoms. ACC writes out atomic charges into common molecular structure files, and offers interactive facilities for statistical analysis and comparison of the results, in both tabular and graphical form. Conclusions Due to high customizability and speed, easy streamlining and the unified platform for calculation and analysis, ACC caters to all fields of life sciences, from drug design to nanocarriers. ACC is freely available via the Internet at http://ncbr.muni.cz/ACC. Electronic supplementary material The online version of this article (doi:10.1186/s13321-015-0099-x) contains supplementary material, which is available to authorized users.
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18
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Lehrer RI. Is there a single porcine protegrin gene? FEBS J 2014; 281:5418-9. [PMID: 25387882 DOI: 10.1111/febs.13143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 11/06/2014] [Accepted: 11/07/2014] [Indexed: 11/26/2022]
Affiliation(s)
- Robert I Lehrer
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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19
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Mohanram H, Bhattacharjya S. Cysteine deleted protegrin-1 (CDP-1): anti-bacterial activity, outer-membrane disruption and selectivity. Biochim Biophys Acta Gen Subj 2014; 1840:3006-16. [PMID: 24997421 DOI: 10.1016/j.bbagen.2014.06.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Revised: 06/14/2014] [Accepted: 06/27/2014] [Indexed: 12/26/2022]
Abstract
BACKGROUND Protegin-1 (PG-1: RGGRLCYCRRRFCVCVGR-amide) assumes a rigid β-hairpin like structure that is stabilized by two disulfide bridges between Cys6-Cys15 and Cys8-Cys13. Previous studies, employing linear analogs of PG-1, with Cys to Ala mutations or modified Cys, have demonstrated that the disulfide bridges are critical for the broad spectrum and salt resistant antimicrobial activity of PG-1. METHODS In order to understand structural and functional roles of disulfide bonds in protegrins, we have synthesized a Cys deleted variant of PG-1 or CDP-1, RGGRLYRRRFVVGR-amide, and two of its analogs, RR11, RLYRRRFVVGR-amide, and LR10, LYRRRFVVGR-amide, containing deletion of residues at the N-terminus. These peptides have been characterized for bactericidal activity and mode of action in lipopolysaccharide (LPS) using optical spectroscopy, ITC and NMR. RESULTS Antibacterial activity, against Gram-negative and Gram-positive strains, of the three peptides follows the order: CDP-1>RR11>LR10. LR10 displays only limited activity toward Gram-negative strains. CDP-1 demonstrates efficient membrane permeabilization and high-affinity interactions with LPS. CDP-1 and RR11 both assume β-hairpin like compact structures in complex with LPS, whereas LR10 adopts an extended conformation in LPS. In zwitterionic DPC micelles CDP-1 and the truncated analog peptides do not adopt folded conformations. MAJOR CONCLUSIONS Despite the absence of stabilizing disulfide bridges CDP-1 shows broad-spectrum antibacterial activity and assumes β-hairpin like structure in complex with LPS. The β-hairpin structure may be essential for outer membrane permeabilization and cell killing.
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Affiliation(s)
- Harini Mohanram
- School of Biological Sciences, Structural Biology and Biochemistry, Nanyang Technological University, 637551, Singapore
| | - Surajit Bhattacharjya
- School of Biological Sciences, Structural Biology and Biochemistry, Nanyang Technological University, 637551, Singapore.
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20
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Dong N, Zhu X, Chou S, Shan A, Li W, Jiang J. Antimicrobial potency and selectivity of simplified symmetric-end peptides. Biomaterials 2014; 35:8028-39. [PMID: 24952979 DOI: 10.1016/j.biomaterials.2014.06.005] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 06/01/2014] [Indexed: 11/19/2022]
Abstract
Because antimicrobial peptides (AMPs) are potentially useful for the treatment of multidrug-resistant infections, more attention is being paid to the structural modification and structure-function relationship of both naturally occurring and synthetic AMPs. Previous studies indicated that Protegrin-1 (PG-1), isolated from porcine leukocytes, exhibited considerable antimicrobial activity and cytotoxicity. The β-turn of PG-1 floated on the surface of bacterial membrane, while its β-strand inserted into the bacterial membrane and formed pores that were dedicated to producing cytotoxicity. For reducing cytotoxicity and improving cells selectivity, we designed a series of simplified symmetric-end peptides by combining the β-turn of PG-1 with simple amino acid repeat sequences. The sequence of designed symmetric-end peptides is (XR)nH(RX)n, (n = 1,2; X represents I, F, W and P; H represents CRRRFC). The symmetric-end peptides displayed antimicrobial activity against both gram-positive and gram-negative bacteria. In particular, (XR)2H(RX)2 (X here is I, F and W) showed greater antimicrobial potency than PG-1. Hemolysis activity and cytotoxicity, detected by using human red blood cells (RBCs) and human embryonic lung fibroblasts MRC-5 cells, were observably lower than the native peptide PG-1. (IR)2H(RI)2 (IR2), folded into β-sheet structures, displayed the highest therapeutic index, suggesting its great cell selectivity. The fluorescence spectroscopy, flow cytometry, and electron microscopy observation indicated that IR2 exhibited great membrane penetration potential by inducing membrane blebbing, disruption and lysis. Collectively, generating symmetric-end β-sheet peptides is a promising strategy for designing effective AMPs with great antimicrobial activities and cell selectivity.
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Affiliation(s)
- Na Dong
- Laboratory of Molecular Nutrition and Immunity, The Institute of Animal Nutrition, Northeast Agricultural University, Harbin, PR China
| | - Xin Zhu
- Laboratory of Molecular Nutrition and Immunity, The Institute of Animal Nutrition, Northeast Agricultural University, Harbin, PR China
| | - Shuli Chou
- Laboratory of Molecular Nutrition and Immunity, The Institute of Animal Nutrition, Northeast Agricultural University, Harbin, PR China
| | - Anshan Shan
- Laboratory of Molecular Nutrition and Immunity, The Institute of Animal Nutrition, Northeast Agricultural University, Harbin, PR China.
| | - Weizhong Li
- Laboratory of Molecular Nutrition and Immunity, The Institute of Animal Nutrition, Northeast Agricultural University, Harbin, PR China
| | - Junguang Jiang
- The State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, PR China
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21
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Rothan HA, Mohamed Z, Sasikumar PG, Reddy KA, Rahman NA, Yusof R. In Vitro Characterization of Novel Protegrin-1 Analogues Against Neoplastic Cells. Int J Pept Res Ther 2013. [DOI: 10.1007/s10989-013-9388-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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22
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Andrès E. Cationic antimicrobial peptides in clinical development, with special focus on thanatin and heliomicin. Eur J Clin Microbiol Infect Dis 2011; 31:881-8. [DOI: 10.1007/s10096-011-1430-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 09/12/2011] [Indexed: 11/21/2022]
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23
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Su Y, Hong M. Conformational disorder of membrane peptides investigated from solid-state NMR line widths and line shapes. J Phys Chem B 2011; 115:10758-67. [PMID: 21806038 PMCID: PMC3222302 DOI: 10.1021/jp205002n] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A challenge in the application of solid-state NMR spectroscopy to membrane peptides and proteins is the relatively broad line widths compared to those for solution NMR spectra. To understand the linewidth contributions to membrane protein NMR spectra, we have measured the inhomogeneous and homogeneous line widths of several well-studied membrane peptides under immobilized conditions. (13)C T(2) relaxation times of uniformly (13)C-labeled residues show that the homogeneous line widths of the peptides are comparable to those of crystalline model compounds under identical (1)H decoupling and magic angle spinning conditions, indicating that the homogeneous line widths are determined by conformation-independent factors, including residual dipolar coupling, J-coupling, and intrinsic T(2) relaxation. However, the membrane peptides exhibit larger apparent line widths than the crystalline compounds, indicating conformational disorder. A cationic cell-penetrating peptide, the human immunodeficiency virus TAT, exhibits the largest apparent line widths, which are about five-fold larger than the homogeneous line widths, while the transmembrane helix of the influenza M2 peptide and the β-hairpin antimicrobial peptide PG-1 show moderately larger apparent line widths than the crystalline compounds. These results are consistent with the random coil nature of the TAT peptide, which contrasts with the intramolecularly hydrogen bonded M2 and PG-1. Cross peak line shapes of 2D double-quantum correlation spectra show that the conformational disorder can occur at the residue level and can result from three origins, lipid-peptide interaction, intrinsic conformational disorder encoded in the amino acid sequence, and side-chain rotameric averaging. A particularly important lipid-peptide interaction for cationic membrane peptides is guanidinium-phosphate ion pair interaction. Thus, NMR line widths and line shapes are useful for understanding the conformational disorder of membrane peptides and proteins.
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Affiliation(s)
- Yongchao Su
- Department of Chemistry, Iowa State University, Ames, IA 50011
| | - Mei Hong
- Department of Chemistry, Iowa State University, Ames, IA 50011
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24
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Su Y, Waring AJ, Ruchala P, Hong M. Structures of β-hairpin antimicrobial protegrin peptides in lipopolysaccharide membranes: mechanism of gram selectivity obtained from solid-state nuclear magnetic resonance. Biochemistry 2011; 50:2072-83. [PMID: 21302955 PMCID: PMC3062705 DOI: 10.1021/bi101975v] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The structural basis for the gram selectivity of two disulfide-bonded β-hairpin antimicrobial peptides (AMPs) is investigated using solid-state nuclear magnetic resonance (NMR) spectroscopy. The hexa-arginine PG-1 exhibits potent activities against both gram-positive and gram-negative bacteria, while a mutant of PG-1 with only three cationic residues maintains gram-positive activity but is 30-fold less active against gram-negative bacteria. We determined the topological structure and lipid interactions of these two peptides in a lipopolysaccharide (LPS)-rich membrane that mimics the outer membrane of gram-negative bacteria and in the POPE/POPG membrane, which mimics the membrane of gram-positive bacteria. (31)P NMR line shapes indicate that both peptides cause less orientational disorder in the LPS-rich membrane than in the POPE/POPG membrane. (13)C chemical shifts and (13)C-(1)H dipolar couplings show that both peptides maintain their β-hairpin conformation in these membranes and are largely immobilized, but the mutant exhibits noticeable intermediate-time scale motion in the LPS membrane at physiological temperature, suggesting shallow insertion. Indeed, (1)H spin diffusion from lipid chains to the peptides shows that PG-1 fully inserts into the LPS-rich membrane whereas the mutant does not. The (13)C-(31)P distances between the most hydrophobically embedded Arg of PG-1 and the lipid (31)P are significantly longer in the LPS membrane than in the POPE/POPG membrane, indicating that PG-1 does not cause toroidal pore defects in the LPS membrane, in contrast to its behavior in the POPE/POPG membrane. Taken together, these data indicate that PG-1 causes transmembrane pores of the barrel-stave type in the LPS membrane, thus allowing further translocation of the peptide into the inner membrane of gram-negative bacteria to kill the cells. In comparison, the less cationic mutant cannot fully cross the LPS membrane because of weaker electrostatic attractions, thus causing weaker antimicrobial activities. Therefore, strong electrostatic attraction between the peptide and the membrane surface, ensured by having a sufficient number of Arg residues, is essential for potent antimicrobial activities against gram-negative bacteria. The data provide a rational basis for controlling gram selectivity of AMPs by adjusting the charge densities.
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Affiliation(s)
- Yongchao Su
- Department of Chemistry, Iowa State University, Ames, IA 50011
| | - Alan J. Waring
- Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA 92697-4560
| | - Piotr Ruchala
- Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095
| | - Mei Hong
- Department of Chemistry, Iowa State University, Ames, IA 50011
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25
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Hong M, Su Y. Structure and dynamics of cationic membrane peptides and proteins: insights from solid-state NMR. Protein Sci 2011; 20:641-55. [PMID: 21344534 DOI: 10.1002/pro.600] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Revised: 01/14/2011] [Accepted: 01/18/2011] [Indexed: 12/11/2022]
Abstract
Many membrane peptides and protein domains contain functionally important cationic Arg and Lys residues, whose insertion into the hydrophobic interior of the lipid bilayer encounters significant energy barriers. To understand how these cationic molecules overcome the free energy barrier to insert into the lipid membrane, we have used solid-state NMR spectroscopy to determine the membrane-bound topology of these peptides. A versatile array of solid-state NMR experiments now readily yields the conformation, dynamics, orientation, depth of insertion, and site-specific protein-lipid interactions of these molecules. We summarize key findings of several Arg-rich membrane peptides, including β-sheet antimicrobial peptides, unstructured cell-penetrating peptides, and the voltage-sensing helix of voltage-gated potassium channels. Our results indicate the central role of guanidinium-phosphate and guanidinium-water interactions in dictating the structural topology of these cationic molecules in the lipid membrane, which in turn account for the mechanisms of this functionally diverse class of membrane peptides.
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Affiliation(s)
- Mei Hong
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
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26
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Li S, Su Y, Luo W, Hong M. Water-protein interactions of an arginine-rich membrane peptide in lipid bilayers investigated by solid-state nuclear magnetic resonance spectroscopy. J Phys Chem B 2010; 114:4063-9. [PMID: 20199036 PMCID: PMC2853767 DOI: 10.1021/jp912283r] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The interaction of an arginine (Arg) residue with water in a transmembrane antimicrobial peptide, PG-1, is investigated by two-dimensional heteronuclear correlation (HETCOR), solid-state nuclear magnetic resonance (NMR) spectroscopy. Using (13)C and (15)N dipolar-edited (1)H-(15)N HETCOR experiments, we unambiguously assigned a water-guanidinium cross-peak that is distinct from intramolecular protein-protein cross-peaks. This water-Arg cross-peak was detected within a short (1)H spin diffusion mixing time of 1 ms, indicating that water is in close contact with the membrane-inserted guanidinium. Together with previously observed short guanidinium-phosphate distances, these solid-state NMR data suggest that the Arg side chains of PG-1 are stabilized by both hydration water and neutralizing lipid headgroups. The membrane deformation that occurs when water and lipid headgroups are pulled into the hydrophobic region of the bilayer is symptomatic of the membrane-disruptive function of this antimicrobial peptide. The water-Arg interactions observed here provide direct experimental evidence for molecular dynamics simulations of the solvation of Arg side chains of membrane proteins by deeply embedded water in lipid bilayers.
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Affiliation(s)
- Shenhui Li
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Yongchao Su
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Wenbin Luo
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Mei Hong
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
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27
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Bolintineanu D, Hazrati E, Davis HT, Lehrer RI, Kaznessis YN. Antimicrobial mechanism of pore-forming protegrin peptides: 100 pores to kill E. coli. Peptides 2010; 31:1-8. [PMID: 19931583 PMCID: PMC2825693 DOI: 10.1016/j.peptides.2009.11.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Accepted: 11/13/2009] [Indexed: 10/20/2022]
Abstract
Antimicrobial peptides (AMPs), important effector molecules of the innate immune system, also provide templates for designing novel antibiotics. Protegrin, an especially potent AMP found in porcine leukocytes, was recently shown to form octameric transmembrane pores. We have employed a combination of experiments and models spanning length scales from the atomistic to the cellular level in order to elucidate the microbicidal mechanism of protegrin. Comparison of the modeling and experimental data suggests that approximately 10-100 protegrin pores are necessary to explain the observed rates of potassium leakage and Escherichia coli death in exponential-phase bacteria. The kinetics of viability loss suggest that bacterial death results largely from uncontrolled ion exchange processes and decay of transmembrane potential. However, ion exchange processes alone cannot account for the experimentally observed cell swelling and osmotic lysis-a redundant "overkill" mechanism most likely to occur in locales with high protegrin concentrations. Although our study is limited to protegrin and E. coli, the timeline of events described herein is likely shared by other AMPs that act primarily by permeabilizing microbial membranes. This work provides many of the missing links in describing antimicrobial action, as well as providing a quantitative connection between several previous experimental and simulation studies of protegrin.
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Affiliation(s)
- Dan Bolintineanu
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - Ehsan Hazrati
- Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
| | - H. Ted Davis
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - Robert I. Lehrer
- Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
| | - Yiannis N. Kaznessis
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
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Kulkarni MM, McMaster WR, Kamysz W, McGwire BS. Antimicrobial peptide-induced apoptotic death of leishmania results from calcium-de pend ent, caspase-independent mitochondrial toxicity. J Biol Chem 2009; 284:15496-504. [PMID: 19357081 DOI: 10.1074/jbc.m809079200] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
alpha- and -defensin-, magainin-, and cathelicidin-type antimicrobial peptides (AMPs) can kill the pathogenic protozoan Leishmania. Comparative studies of a panel of AMPs have defined two distinct groups: those that induce nonapoptotic (Class I) and apoptotic (Class II) parasite killing based on their differential ability to induce phosphatidyl serine exposure, loss of mitochondrial membrane potential and decreased ATP production, induction of caspase-3/7 and -12 activity, and DNA degradation. Class II AMPs cause rapid influx of the vital stain SYTOX and an increase in intracellular Ca2+, whereas Class I AMPs cause a slow accumulation of SYTOX and do not affect intracellular Ca2+ levels. Inhibitors of cysteine or caspase proteases diminished fast influx of SYTOX through the surface membrane and DNA degradation but do not ablate the annexin V staining or the induction of apoptosis by Class II AMPs. This suggests that the changes in surface permeability in AMP-mediated apoptosis are related to the downstream events of intracellular cysteine/caspase activation or the loss of ATP. The activation of caspase-12-like activity was Ca(2+)-dependent, and inhibitors of voltage-gated and nonspecific Ca2+ channels diminished this activity. Flufenamic acid, a nonspecific Ca2+ inhibitor, completely ablated AMP-induced mitochondrial dysfunction and cell death, indicating the importance of dysregulation of Ca2+ in antimicrobial peptide-induced apoptosis.
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Affiliation(s)
- Manjusha M Kulkarni
- Division of Infectious Diseases and Center for Microbial Interface Biology, The Ohio State University Medical Center, Columbus, Ohio 43210, USA
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29
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Tang M, Hong M. Structure and mechanism of beta-hairpin antimicrobial peptides in lipid bilayers from solid-state NMR spectroscopy. MOLECULAR BIOSYSTEMS 2009; 5:317-22. [PMID: 19396367 PMCID: PMC2866158 DOI: 10.1039/b820398a] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The membrane-bound structure, lipid interaction, and dynamics of the arginine-rich beta-hairpin antimicrobial peptide PG-1 as studied by solid-state NMR are highlighted here. A variety of solid-state NMR techniques, including paramagnetic relaxation enhancement, (1)H and (19)F spin diffusion, dipolar recoupling distance experiments, and 2D anisotropic-isotropic correlation experiments, are used to elucidate the structural basis for the membrane disruptive activity of this representative beta-hairpin antimicrobial peptide. We found that PG-1 structure is membrane dependent: in bacteria-mimetic anionic lipid membranes the peptide forms oligomeric transmembrane beta-barrels, whereas in cholesterol-rich membranes mimicking eukaryotic cells the peptide forms beta-sheet aggregates on the surface of the bilayer. PG-1 causes toroidal pore defects in the anionic membrane, suggesting that the cationic arginine residues drag the lipid phosphate groups along as the peptide inserts. Mutation of PG-1 to reduce the number of cationic residues or to change the arginine guanidinium structure significantly changes the degree of insertion and orientation of the peptide in the lipid membrane, resulting in much weaker antimicrobial activities.
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Affiliation(s)
- Ming Tang
- Department of Chemistry, Iowa State University, Ames, IA 50011
| | - Mei Hong
- Department of Chemistry, Iowa State University, Ames, IA 50011
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30
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Dai JG, Xie HW, Jin G, Wang WG, Zhang Y, Guo Y. Preliminary study on high-level expression of tandem-arranged tachyplesin-encoding gene in Bacillus subtilis Wb800 and its antibacterial activity. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2009; 11:109-117. [PMID: 18670810 DOI: 10.1007/s10126-008-9125-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Accepted: 06/10/2008] [Indexed: 05/26/2023]
Abstract
To produce tachyplesin, an antimicrobial peptide, by a stable and efficient gene engineering approach, cDNAs containing single tachyplesin gene sequence (tac)(1) and tandem repeat of tachyplesin gene sequence (tac2) were respectively developed by annealing two synthesized complementary single-stranded DNAs and constructed into pSBPTQ shuttle vector under the control of the SacB.p.s promoter. The vectors containing the target gene sequence were then transformed into Bacillus subtilis WB800, respectively. Both expression of tac and tac2 were induced by 2% sucrose. The fermentation supernatant was purified by regenerated cellulose membrane tubing (MWCO 2000) and the secreted TAC(2) and TAC2 were about 5 and 10 mg/l of supernatant, respectively. The antimicrobial activities of TAC and TAC2 were measured by the size of bacteriostatic circle of the fermentation supernatants against Escherichia coli K88. Ultrastructural alteration of E. coli K88 and Salmonella typhimurium was observed under scanning electron microscope and transmission electron microscopy. The results showed that in comparison with TAC, TAC2 was expressed at a higher level and also indicating strong antimicrobial activity both in vitro and in vivo.
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Affiliation(s)
- Jian-guo Dai
- School of Applied Chemistry and Biological Technology, Shenzhen Polytechnic, Shenzhen 518055, China.
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31
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Tang M, Waring AJ, Hong M. Effects of arginine density on the membrane-bound structure of a cationic antimicrobial peptide from solid-state NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1788:514-21. [PMID: 19059201 DOI: 10.1016/j.bbamem.2008.10.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 10/02/2008] [Accepted: 10/30/2008] [Indexed: 11/30/2022]
Abstract
Solid-state NMR spectroscopy is used to determine the membrane-bound topological structure of a cationic beta-hairpin antimicrobial peptide in which the number of Arg residues has been halved. The parent peptide, PG-1, was previously found to form transmembrane beta-barrels in anionic membranes where the Arg residues complex with the lipid phosphate groups to cause toroidal pore defects in the membrane. In comparison, the charge-attenuated and less active mutant studied here forms beta-sheets that lie on the surface of the zwitterionic membrane and only partially insert into the anionic membrane. The mutant also exhibits much looser contact with the lipid headgroups. These results indicate that transmembrane insertion and tight Arg-phosphate association are two important elements for strong antimicrobial activities of this class of peptides. Comparison with other beta-hairpin antimicrobial peptides studied so far further suggests a relative potency scale for the various mechanisms of action for the beta-sheet family of antimicrobial peptides. The transmembrane insertion-toroidal pore mechanism is the most potent in disrupting the lipid bilayer, followed by the large-amplitude in-plane motional mechanism. The carpet model, where peptides aggregate on the membrane surface to cause lateral expansion and eventual micellization of the membrane, is a weaker mechanism of action.
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Affiliation(s)
- Ming Tang
- Department of Chemistry, Iowa State University, Ames, IA 50011, USA
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32
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Tang M, Waring AJ, Hong M. Arginine dynamics in a membrane-bound cationic beta-hairpin peptide from solid-state NMR. Chembiochem 2008; 9:1487-92. [PMID: 18442147 DOI: 10.1002/cbic.200800005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The site-specific motion of Arg residues in a membrane-bound disulfide-linked antimicrobial peptide, protegrin-1 (PG-1), was investigated by using magic-angle-spinning solid-state NMR spectroscopy to better understand the membrane insertion and lipid interaction of this cationic membrane-disruptive peptide. The C-H and N-H dipolar couplings and 13C chemical shift anisotropies were measured in the anionic POPE/POPG membrane, and were found to be reduced from the rigid-limit values by varying extents; this indicates the presence of segmental motion. An Arg residue at the beta-turn region of the peptide showed much weaker spin interactions, which indicates larger amplitudes of motion than an Arg residue in the beta-strand region of the peptide. This is consistent with the exposure of the beta turn to the membrane surface and the immersion of the beta strand in the hydrophobic middle of the membrane, and supports the previously proposed oligomerization of the peptide into beta barrels in the anionic membrane. The 13C T2 and 1H T(1rho) relaxation times indicate that the beta-turn backbone undergoes large-amplitude intermediate-timescale motion in the fluid phase of the membrane; this causes significant line broadening and loss of spectral intensity. This study illustrates the strong correlation between the dynamics and structure of membrane proteins, and the capability of solid-state NMR spectroscopy to provide detailed information on site-specific dynamics in complex membrane-protein assemblies.
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Affiliation(s)
- Ming Tang
- Department of Chemistry, Iowa State University, Ames, IA 50011, USA.
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33
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Zhu S, Wei L, Yamasaki K, Gallo RL. Activation of cathepsin L by the cathelin-like domain of protegrin-3. Mol Immunol 2008; 45:2531-6. [PMID: 18289683 DOI: 10.1016/j.molimm.2008.01.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 01/05/2008] [Accepted: 01/08/2008] [Indexed: 11/18/2022]
Abstract
The cathelin-like domain (CLD) of the antimicrobial cathelicidin family constitutes a unique protein family with structural similarity to cystatins, the cysteine protease inhibitors. CLDs are derived from the processed amino-terminal prosequence of the cathelicidin precursors with conservation across the vertebrate lineage ranging from fish to human. Initial attempt to characterize a possible inhibitory activity of protegrin-3 (PG3) CLD protein (a member of the multigene family of porcine cathelicidins) against several proteases led to an unexpected finding that PG3 CLD efficiently activated rather than inhibited human cathepsin L. Partial deletion of the L2 loop of PG3 CLD, a structurally equivalent region important in interaction of cystatins with proteases, significantly decreased its activating effect on cathepsin L. A complex model based on this functional loop was proposed to explain this unexpected effect, in which evolutionary emergence of completely opposite biological activity could be associated with structural discrepancies of the loop due to sequence variations between pig and human. Our results provide new insights into deeper understanding of the immune-related biological activity of this so-called pro-domain of the cathelicidin family.
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Affiliation(s)
- Shunyi Zhu
- Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
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34
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Mani R, Waring AJ, Hong M. Conformation, dynamics, and insertion of a noncysteine-containing protegrin-1 analogue in lipid membranes from solid-state NMR spectroscopy. Chembiochem 2008; 8:1877-84. [PMID: 17868158 DOI: 10.1002/cbic.200700335] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Disulfide-bonded beta-hairpin structures are common among antimicrobial peptides. Disulfide bonds are known to be important for antimicrobial activity, but the underlying structural reason is not well understood. We have investigated the membrane-bound structure of a disulfide-deleted analogue of the antimicrobial peptide protegrin-1, in which the four Cys residues were replaced by Ala. The secondary structure, dynamics, and topology of this Ala-PG1 peptide in the membrane were determined by using magic-angle-spinning NMR spectroscopy. Conformation-dependent (13)C isotropic chemical shifts of multiple (13)C-labeled residues were obtained from 1D cross-polarization and direct-polarization spectra, and from 2D J-coupling-mediated (13)C-(13)C correlation spectra. Most labeled residues exhibited two conformations: a random coil and a beta-sheet structure. The dual-conformation property was present in both anionic lipid bilayers, which mimic the bacterial membrane, and zwitterionic cholesterol-containing bilayers, which mimic the eukaryotic cell membrane. The mobility of the peptide was measured by using a 2D C-H dipolar-shift correlation experiment. The random-coil fraction was highly mobile whereas the beta-sheet component was rigid. (1)H spin diffusion from the lipid chains to the peptide indicates that the beta-sheet component was well inserted into the anionic membrane, but surface bound in the cholesterol-containing neutral membrane. Thus, the removal of disulfide bonds changed some PG-1 molecules to highly mobile random coils that were poorly associated with the lipid membrane, but other molecules retained a beta-sheet conformation and had a similar membrane-binding topology to the parent peptide. Thus, the reduced antimicrobial activity of Ala-PG1 was largely due to the reduced number of insertion-competent beta-sheet molecules, rather than uniformly weakened activity of identically structured peptides.
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Affiliation(s)
- Rajeswari Mani
- Department of Chemistry, Iowa State University, Ames, IA 50011, USA
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35
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Abstract
The concept of the therapeutic ratio (TR) is central to understanding the rationale for using radioprotectors. The TR relates tumor control probabilities and normal tissue complication probabilities to one another. An ideal radioprotector will reduce the latter without compromising the former. It should also be minimally toxic itself. Radioprotective strategies can be classified under the categories of protection, mitigation, and treatment. Protectors are administered before radiotherapy (RT) and are designed to prevent radiation-induced injury. Amifostine is the prototype drug. Mitigants are administered after RT but before the phenotypic expression of injury and are intended to ameliorate injury. Palifermin can be considered as the prototype mitigant. Treatment is a strategy that is predominantly palliative and supportive in nature. Pharmacologic radioprotective strategies should be integrated with physical strategies such as intensity-modulated radiotherapy to realize their maximum clinical potential.
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Affiliation(s)
- David M Brizel
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
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36
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Radek K, Gallo R. Antimicrobial peptides: natural effectors of the innate immune system. Semin Immunopathol 2007; 29:27-43. [PMID: 17621952 DOI: 10.1007/s00281-007-0064-5] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Antimicrobial peptides (AMPs) are an evolutionarily conserved component of the innate immune system that defend against invading bacteria, viruses, and fungi through membrane or metabolic disruption. The efficiency of host defense via AMPs derives from the ability of these peptides to quickly identify and eradicate foreign pathogens through precise biochemical mechanisms. Recent advances in this field have expanded the repertoire of activities for AMPs to include immunostimulatory and immunomodulatory capacity as a catalyst for secondary host defense mechanisms. Further scrutiny of the biochemical and regulatory mechanisms of AMPs will lead to novel alternative approaches to the treatment of human pathogenic disorders.
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Affiliation(s)
- Katherine Radek
- Division of Dermatology, University of California, San Diego, CA, USA
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37
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Tang M, Waring AJ, Hong M. Phosphate-Mediated Arginine Insertion into Lipid Membranes and Pore Formation by a Cationic Membrane Peptide from Solid-State NMR. J Am Chem Soc 2007; 129:11438-46. [PMID: 17705480 DOI: 10.1021/ja072511s] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The insertion of charged amino acid residues into the hydrophobic part of lipid bilayers is energetically unfavorable yet found in many cationic membrane peptides and protein domains. To understand the mechanism of this translocation, we measured the (13)C-(31)P distances for an Arg-rich beta-hairpin antimicrobial peptide, PG-1, in the lipid membrane using solid-state NMR. Four residues, including two Arg's, scattered through the peptide were chosen for the distance measurements. Surprisingly, all residues show short distances to the lipid (31)P: 4.0-6.5 A in anionic POPE/POPG membranes and 6.5-8.0 A in zwitterionic POPC membranes. The shortest distance of 4.0 A, found for a guanidinium Czeta at the beta-turn, suggests N-H...O-P hydrogen bond formation. Torsion angle measurements of the two Arg's quantitatively confirm that the peptide adopts a beta-hairpin conformation in the lipid bilayer, and gel-phase 1H spin diffusion from water to the peptide indicates that PG-1 remains transmembrane in the gel phase of the membrane. For this transmembrane beta-hairpin peptide to have short (13)C-(31)P distances for multiple residues in the molecule, some phosphate groups must be embedded in the hydrophobic part of the membrane, with the local (31)P plane parallel to the beta-strand. This provides direct evidence for toroidal pores, where some lipid molecules change their orientation to merge the two monolayers. We propose that the driving force for this toroidal pore formation is guanidinium-phosphate complexation, where the cationic Arg residues drag the anionic phosphate groups along as they insert into the hydrophobic part of the membrane. This phosphate-mediated translocation of guanidinium ions may underlie the activity of other Arg-rich antimocrobial peptides and may be common among cationic membrane proteins.
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Affiliation(s)
- Ming Tang
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
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38
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Andrès E, Dimarcq JL. Peptides antimicrobiens cationiques: de l'étude de l'immunité innée à la production de médicaments. Mise à jour. Med Mal Infect 2007; 37:194-9. [PMID: 17306486 DOI: 10.1016/j.medmal.2006.09.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Accepted: 09/11/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Host defense, cationic anti-microbial peptides are recognized as an important component of innate immune response in most multicellular organisms. NEW FEATURES These cationic amphipathic peptides include 20 to 50 amino acids and several hundreds of peptides have been identified. They have a broad spectrum activity against bacterial, fungal, and viral pathogens. The mode of action is best known for cecropins and magainins, which act on the cytoplasmic membrane of microorganisms, causing its disruption by a detergent-like activity and pore formation. Several of these peptides or analogs (from magainin, protegrin, indolicidin, and histatin) are under advanced clinical development, especially when used for localized infections. PROJECTS AND PERSPECTIVES Several other molecules (rBPI, heliomicin, and thanatine) are currently under development for various systemic infections. These will probably be important drugs for future anti-infectious therapy.
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Affiliation(s)
- E Andrès
- Service de Médecine Interne, Clinique Médicale B, Hôpitaux Universitaires de Strasbourg, France.
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39
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Tang M, Waring AJ, Hong M. Trehalose-protected lipid membranes for determining membrane protein structure and insertion. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 184:222-7. [PMID: 17084650 PMCID: PMC2561142 DOI: 10.1016/j.jmr.2006.10.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2006] [Revised: 10/01/2006] [Accepted: 10/16/2006] [Indexed: 05/12/2023]
Abstract
Trehalose preserves lipid bilayers during dehydration and rehydration by replacing water to form hydrogen bonds between its own OH groups and lipid headgroups. We compare the lipid conformation and dynamics between trehalose-protected lyophilized membranes and hydrated membranes, to assess the suitability of the trehalose-containing membrane as a matrix for membrane protein structure determination. (31)P spectra indicate that the lipid headgroup of trehalose-protected dry POPC membrane (TRE-POPC) have an effective phase transition temperature that is approximately 50K higher than that of the hydrated POPC membrane. In contrast, the acyl chains have similar transition temperatures in the two membranes. Intramolecular lipid (13)C'-(31)P distances are the same in TRE-POPC and crystalline POPC, indicating that the lipid headgroup and glycerol backbone conformation is unaffected by trehalose incorporation. Intermolecular (13)C-(31)P distances between a membrane peptide and the lipid headgroups are 10% longer in the hydrated membrane at 226 K than in the trehalose-protected dry membrane at 253 K. This is attributed to residual motions in the hydrated membrane, manifested by the reduced (31)P chemical shift anisotropy, even at the low temperature of 226 K. Thus, trehalose lyoprotection facilitates the study of membrane protein structure by allowing experiments to be conducted at higher temperatures than possible with the hydrated membranes.
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Affiliation(s)
- Ming Tang
- Department of Chemistry, Iowa State University, Ames, IA 50011, USA
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40
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Mani R, Cady SD, Tang M, Waring AJ, Lehrer RI, Hong M. Membrane-dependent oligomeric structure and pore formation of a beta-hairpin antimicrobial peptide in lipid bilayers from solid-state NMR. Proc Natl Acad Sci U S A 2006; 103:16242-7. [PMID: 17060626 PMCID: PMC1637567 DOI: 10.1073/pnas.0605079103] [Citation(s) in RCA: 199] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We used solid-state NMR spectroscopy to investigate the oligomeric structure and insertion of protegrin-1 (PG-1), a beta-hairpin antimicrobial peptide, in lipid bilayers that mimic either the bacterial inner membrane [palmitoyloleoylphosphatidyl ethanolamine and palmitoyloleoylphosphatidylglycerol (POPE/POPG) bilayers] or the red blood cell membrane [neutral palmitoyloleoylphosphatidylcholine (POPC)/cholesterol bilayers]. (1)H spin diffusion from lipids to the peptide indicates that PG-1 contacts both the lipid acyl chains and the headgroups in the anionic membrane but resides far from the lipid chains in the POPC/cholesterol bilayer. (19)F spin diffusion data indicates that 75% of the beta-hairpins have homodimerized N strands and C strands in the anionic membrane. The resulting (NCCN)(n) multimer suggests a membrane-inserted beta-barrel enclosing a water pore. The lipids surrounding the beta-barrel have high orientational disorder and chain upturns, thus they may act as fillers for the pore. These results revise several features of the toroidal pore model, first proposed for magainin and subsequently applied to PG-1. In the POPC/cholesterol membrane, the N and C strands of PG-1 cluster into tetramers, suggesting the formation of beta-sheets on the membrane surface. Thus, the membrane composition plays a decisive role in defining the assembly and insertion of PG-1. The different oligomeric structures of PG-1 help to explain its greater toxicity for bacteria than for eukaryotic cells.
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Affiliation(s)
- Rajeswari Mani
- *Department of Chemistry, Iowa State University, Ames, IA 50011; and
| | - Sarah D. Cady
- *Department of Chemistry, Iowa State University, Ames, IA 50011; and
| | - Ming Tang
- *Department of Chemistry, Iowa State University, Ames, IA 50011; and
| | - Alan J. Waring
- Department of Medicine, University of California School of Medicine, Los Angeles, CA 90095
| | - Robert I. Lehrer
- Department of Medicine, University of California School of Medicine, Los Angeles, CA 90095
| | - Mei Hong
- *Department of Chemistry, Iowa State University, Ames, IA 50011; and
- To whom correspondence should be addressed. E-mail:
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41
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Ishitsuka Y, Pham DS, Waring AJ, Lehrer RI, Lee KYC. Insertion selectivity of antimicrobial peptide protegrin-1 into lipid monolayers: effect of head group electrostatics and tail group packing. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:1450-60. [PMID: 16989771 DOI: 10.1016/j.bbamem.2006.08.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Revised: 07/31/2006] [Accepted: 08/01/2006] [Indexed: 11/24/2022]
Abstract
The ability to selectively target the harmful microbial membrane over that of the host cell is one of the most important characteristics of the antimicrobial peptides (AMPs). This selectivity strongly depends on the chemical and structural properties of the lipids that make up the cell membrane. A systematic study of the initial membrane selectivity of protegrin-1 (PG-1), a beta-sheet AMP, was performed using Langmuir monolayers. Constant pressure insertion assay was used to quantify the amount of PG-1 insertion and fluorescence microscopy was employed to observe the effect of PG-1 on lipid ordering. Charge and packing properties of the monolayer were altered by using lipids with different head groups, substituting saturated with unsaturated lipid tail group(s) and incorporating spacer molecules. PG-1 inserted most readily into anionic films composed of phosphatidylglycerol (PG) and lipid A, consistent with its high selectivity for microbial membranes. It also discriminated between zwitteranionic phospholipids, inserting more readily into phosphatidylcholine (PC) monolayers than those composed of phosphatidylethanolamine, potentially explaining why PG-1 is hemolytic for PC-rich human erythrocytes and not for the PE-rich erythrocytes of ruminants. Increased packing density of the monolayer by increased surface pressure, increased tail group saturation or incorporation of dihydrocholesterol diminishes the insertion of PG-1. Fluorescence microscopy shows that lipid packing is disordered upon PG-1 insertion. However, the presence of PG-1 can still affect lipid morphology even with no observed PG-1 insertion. These results show the important role that lipid composition of the cell membrane plays in the activity of AMPs.
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Affiliation(s)
- Yuji Ishitsuka
- Department of Chemistry, The Institute for Biophysical Dynamics and the James Franck Institute, The University of Chicago, Chicago, IL 60637, USA
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42
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Epstein JB, Klasser GD. Emerging approaches for prophylaxis and management of oropharyngeal mucositis in cancer therapy. Expert Opin Emerg Drugs 2006; 11:353-73. [PMID: 16634706 DOI: 10.1517/14728214.11.2.353] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Oral mucositis is a common treatment-limiting side effect of cancer therapy that may have a significant impact on quality of life and on the cost of care. Oral mucositis is the most distressing complication of cancer therapy as reported by head and neck cancer patients, in patients receiving dose-dense myelosuppressive chemotherapy and in patients receiving haematopoietic stem cell transplant. Mucositis may increase the risk of local and systemic infection, particularly in myelosuppressed patients. Severe oral mucositis can lead to the need to interrupt or discontinue cancer therapy, and thus may impact cure of the primary disease. Current care of patients with mucositis is essentially palliative, and includes appropriate oral hygiene, nonirritating diet and oral care products, topical palliative mouth rinses, topical anaesthetics and use of systemic opioid analgesics. Emerging approaches for prevention and treatment of oral mucositis are developing based on an increasing understanding of the pathobiology of mucosal damage and repair. New interventions are expected to be administered based on the mechanisms of initiation, progression and resolution of the condition. The approval by the FDA of keratinocyte growth factor (palifermin; Amgen) in 2004 represents a new step in prevention of oral mucositis in stem cell transplant patients based on the increasing understanding of the pathogenesis of mucositis. Progress in the prevention and management of mucositis will improve quality of life, reduce cost of care and facilitate completion of more intensive cancer chemotherapy and radiotherapy protocols. Improved management of mucositis may allow implementation of cancer treatment protocols that are currently excessively mucotoxic, but have potentially higher cure rates of the malignant disease.
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Affiliation(s)
- Joel B Epstein
- Department of Oral Medicine and Diagnostic Sciences, University of Illinois at Chicago, College of Dentistry, 801 South Paulina St, MC 838, Chicago, Illinois 60612, USA
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43
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Doherty T, Waring AJ, Hong M. Peptide-lipid interactions of the beta-hairpin antimicrobial peptide tachyplesin and its linear derivatives from solid-state NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:1285-91. [PMID: 16678119 DOI: 10.1016/j.bbamem.2006.03.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2005] [Revised: 03/13/2006] [Accepted: 03/14/2006] [Indexed: 10/24/2022]
Abstract
The peptide-lipid interaction of a beta-hairpin antimicrobial peptide tachyplesin-1 (TP-1) and its linear derivatives are investigated to gain insight into the mechanism of antimicrobial activity. (31)P and (2)H NMR spectra of uniaxially aligned lipid bilayers of varying compositions and peptide concentrations are measured to determine the peptide-induced orientational disorder and the selectivity of membrane disruption by tachyplesin. The disulfide-linked TP-1 does not cause any disorder to the neutral POPC and POPC/cholesterol membranes but induces both micellization and random orientation distribution to the anionic POPE/POPG membranes above a peptide concentration of 2%. In comparison, the anionic POPC/POPG bilayer is completely unaffected by TP-1 binding, suggesting that TP-1 induces negative curvature strain to the membrane as a mechanism of its action. Removal of the disulfide bonds by substitution of Cys residues with Tyr and Ala abolishes the micellization of POPE/POPG bilayers but retains the orientation randomization of both POPC/POPG and POPE/POPG bilayers. Thus, linear tachyplesin derivatives have membrane disruptive abilities but use different mechanisms from the wild-type peptide. The different lipid-peptide interactions between TP-1 and other beta-hairpin antimicrobial peptides are discussed in terms of their molecular structure.
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Affiliation(s)
- Timothy Doherty
- Department of Chemistry, Iowa State University, Ames, IA 50011, USA
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Tang M, Waring AJ, Hong M. Intermolecular packing and alignment in an ordered beta-hairpin antimicrobial peptide aggregate from 2D solid-state NMR. J Am Chem Soc 2006; 127:13919-27. [PMID: 16201813 DOI: 10.1021/ja0526665] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The aggregation and packing of a membrane-disruptive beta-hairpin antimicrobial peptide, protegrin-1 (PG-1), in the solid state are investigated to understand its oligomerization and hydrogen-bonding propensity. Incubation of PG-1 in phosphate buffer saline produced well-ordered nanometer-scale aggregates, as indicated by 13C and 15N NMR line widths, chemical shifts, and electron microscopy. Two-dimensional 13C and 1H spin diffusion experiments using C-terminus strand and N-terminus strand labeled peptides indicate that the beta-hairpin molecules in these ordered aggregates are oriented parallel to each other with like strands lining the intermolecular interface. In comparison, disordered and lyophilized peptide samples are randomly packed with both parallel and antiparallel alignments. The PG-1 aggregates show significant immobilization of the Phe ring near the beta-turn, further supporting the structural ordering. The intermolecular packing of PG-1 found in the solid state is consistent with its oligomerization in lipid bilayers. This solid-state aggregation approach may be useful for determining the quaternary structure of peptides in general and for gaining insights into the oligomerization of antimicrobial peptides in lipid bilayers in particular.
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Affiliation(s)
- Ming Tang
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
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Jing W, Prenner EJ, Vogel HJ, Waring AJ, Lehrer RI, Lohner K. Headgroup structure and fatty acid chain length of the acidic phospholipids modulate the interaction of membrane mimetic vesicles with the antimicrobial peptide protegrin-1. J Pept Sci 2006; 11:735-43. [PMID: 16059971 DOI: 10.1002/psc.702] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The interaction of protegrin-1 (PG-1), a small beta-sheet antimicrobial peptide with acidic phospholipid model membranes was investigated by differential scanning calorimetry. We found that PG-1 can distinguish between liposomes of the anionic phospholipids DPPG, DPPS and DPPA, eventhough the headgroups of these phospholipids all have the same net charge and they carry the same hydrocarbon chains. Specifically, PG-1 had only a minor effect on the thermotropic phase behavior of DPPA liposomes, while it interacted preferentially with the fluid phase of DPPS. Furthermore, PG-1 could induce a phase separation in DPPG liposomes resulting in the formation of peptide-rich domains even at low concentrations of the peptide. However, this peptide-rich domain was not evident when the fatty acyl chains were longer or shorter by two carbon atoms. In addition, PG-1 can also form peptide-rich domains in DPPS vesicles but only at high concentrations of the peptide. These results suggest that in addition to an overall negative charge, the structural features of the phospholipid headgroups, lipid packing and thus membrane fluidity will influence the interaction with PG-1, thereby modulating its biological activity.
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Affiliation(s)
- Weiguo Jing
- Institute of Biophysics and X-ray Structure Research, Austrian Academy of Sciences, Graz
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Mani R, Waring AJ, Lehrer RI, Hong M. Membrane-disruptive abilities of beta-hairpin antimicrobial peptides correlate with conformation and activity: a 31P and 1H NMR study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1716:11-8. [PMID: 16182236 DOI: 10.1016/j.bbamem.2005.08.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Revised: 08/08/2005] [Accepted: 08/23/2005] [Indexed: 11/28/2022]
Abstract
The membrane interaction and solution conformation of two mutants of the beta-hairpin antimicrobial peptide, protegrin-1 (PG-1), are investigated to understand the structural determinants of antimicrobial potency. One mutant, [A(6,8,13,15)] PG-1, does not have the two disulfide bonds in wild-type PG-1, while the other, [Delta(4,18) G10] PG-1, has only half the number of cationic residues. 31P solid-state NMR lineshapes of uniaxially aligned membranes indicate that the membrane disorder induced by the three peptides decreases in the order of PG-1 > [Delta(4,18) G10] PG-1>>[A(6,8,13,15)] PG-1. Solution NMR studies of the two mutant peptides indicate that [Delta(4,18) G10] PG-1 preserves the beta-hairpin fold of the wild-type peptide while [A(6,8,13,15)] PG-1 adopts a random coil conformation. These NMR results correlate well with the known activities of these peptides. Thus, for this class of peptides, the presence of a beta-hairpin fold is more essential than the number of cationic charges for antimicrobial activity. This study indicates that 31P NMR lineshapes of uniaxially aligned membranes are well correlated with antimicrobial activity, and can be used as a diagnostic tool to understand the peptide-lipid interactions of these antimicrobial peptides.
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Affiliation(s)
- Rajeswari Mani
- Department of Chemistry, Iowa State University, Ames, IA 50011, USA
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Marasinghe PAB, Buffy JJ, Schmidt-Rohr K, Hong M. Membrane Curvature Change Induced by an Antimicrobial Peptide Detected by 31P Exchange NMR. J Phys Chem B 2005; 109:22036-44. [PMID: 16853861 DOI: 10.1021/jp054396i] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The influence of an antimicrobial peptide, protegrin-1 (PG-1), on the curvature and lateral diffusion coefficient (D(L)) of phosphocholine bilayers is investigated using one- (1D) and two-dimensional (2D) (31)P exchange NMR. The experiments utilize the fact that lipid lateral diffusion over the curved surface of vesicles changes the molecular orientation and thus the (31)P chemical shift anisotropy. This reorientation is manifested in 2D spectra as off-diagonal intensities and in 1D stimulated-echo experiments as reduced echo heights. The 2D spectra give information on the reorientation-angle distribution while the decay of the stimulated-echo intensity, which closely tracks the second-order correlation function in our experiments, yields the correlation times of the reorientation. The relationships among the 2D exchange spectra, stimulated-echo intensities, the correlation function, and reorientation-angle distributions are analyzed in detail. In the absence of PG-1, both dilaurylphosphotidylcholine (DLPC) and palmitoyloleoylphosphatidylcholine (POPC) vesicles show biexponential decays of the stimulated-echo intensities to equilibrium values of 0.20-0.25, suggesting that the curvature of the lipid vesicles has a bimodal distribution. The addition of PG-1 to DLPC vesicles increased the decay time constants, indicating that D(L) decreases due to peptide binding. In contrast, the addition of PG-1 to POPC vesicles decreased the decay constants by three to fivefold, indicating that the POPC vesicles are fragmented into smaller vesicles. On the basis of the changes in D(L) and the decay constants, we estimate that the radius of the POPC vesicles decreases by threefold due to PG-1 binding. Simulations of the 2D exchange spectra yielded quantitative reorientation-angle distributions that are consistent with the bimodal distributions of the vesicle curvature and the effects of the peptide on the two types of lipid bilayers. Thus, (31)P exchange NMR provides useful insights into the membrane morphological changes induced by this antimicrobial peptide.
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Affiliation(s)
- P A B Marasinghe
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
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Deslouches B, Islam K, Craigo JK, Paranjape SM, Montelaro RC, Mietzner TA. Activity of the de novo engineered antimicrobial peptide WLBU2 against Pseudomonas aeruginosa in human serum and whole blood: implications for systemic applications. Antimicrob Agents Chemother 2005; 49:3208-16. [PMID: 16048927 PMCID: PMC1196285 DOI: 10.1128/aac.49.8.3208-3216.2005] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cationic amphipathic peptides have been extensively investigated as a potential source of new antimicrobials that can complement current antibiotic regimens in the face of emerging drug-resistant bacteria. However, the suppression of antimicrobial activity under certain biologically relevant conditions (e.g., serum and physiological salt concentrations) has hampered efforts to develop safe and effective antimicrobial peptides for clinical use. We have analyzed the activity and selectivity of the human peptide LL37 and the de novo engineered antimicrobial peptide WLBU2 in several biologically relevant conditions. The host-derived synthetic peptide LL37 displayed high activity against Pseudomonas aeruginosa but demonstrated staphylococcus-specific sensitivity to NaCl concentrations varying from 50 to 300 mM. Moreover, LL37 potency was variably suppressed in the presence of 1 to 6 mM Mg(2+) and Ca(2+) ions. In contrast, WLBU2 maintained its activity in NaCl and physiologic serum concentrations of Mg(2+) and Ca(2+). WLBU2 is able to kill P. aeruginosa (10(6) CFU/ml) in human serum, with a minimum bactericidal concentration of <9 microM. Conversely, LL37 is inactive in the presence of human serum. Bacterial killing kinetic assays in serum revealed that WLBU2 achieved complete bacterial killing in 20 min. Consistent with these results was the ability of WLBU2 (15 to 20 microM) to eradicate bacteria from ex vivo samples of whole blood. The selectivity of WLBU2 was further demonstrated by its ability to specifically eliminate P. aeruginosa in coculture with human monocytes or skin fibroblasts without detectable adverse effects to the host cells. Finally, WLBU2 displayed potent efficacy against P. aeruginosa in an intraperitoneal infection model using female Swiss Webster mice. These results establish a potential application of WLBU2 in the treatment of bacterial sepsis.
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Affiliation(s)
- Berthony Deslouches
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, E1240 Biochemical Science Tower, Lothrop Street, Pittsburgh, PA 15261, USA
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Doncel G, Mauck C. Vaginal microbicides: a novel approach to preventing sexual transmission of HIV. Curr HIV/AIDS Rep 2005; 1:25-32. [PMID: 16091220 DOI: 10.1007/s11904-004-0004-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The AIDS epidemic continues its unrelentless expansion. According to the Joint United Nations Programme on HIV/AIDS, there are more than 40 million people living with HIV, and more than 15,000 new infections occur every day. One approach to curbing HIV is the development of topical microbicidal agents or microbicides. These are compounds designed to protect the body's mucosal surfaces from infection by sexually transmitted disease-causing pathogens, including HIV. Several candidates are in preclinical stages; however, only a handful have been tested in humans for safety, and even fewer are ready for clinical efficacy trials. In this update, we describe microbicide research and development, including preclinical screening algorithms, ideal properties, compounds in the pipeline, and future prospects. This review is based on a previous work, which has been updated to contain new information, especially regarding microbicide candidates in preclinical and clinical stages of development.
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Affiliation(s)
- Gustavo Doncel
- CONRAD, Eastern Virginia Medical School, 601 Colley Avenue, Norfolk, VA 23507, USA.
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Buffy JJ, Waring AJ, Hong M. Determination of peptide oligomerization in lipid bilayers using 19F spin diffusion NMR. J Am Chem Soc 2005; 127:4477-83. [PMID: 15783230 DOI: 10.1021/ja043621r] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aggregation or oligomerization is important for the function of many membrane peptides such as ion channels and antimicrobial peptides. However, direct proof of aggregation and the determination of the number of molecules in the aggregate have been difficult due to the lack of suitable high-resolution methods for membrane peptides. We propose a 19F spin diffusion magic-angle-spinning NMR technique to determine the oligomeric state of peptides bound to the lipid bilayer. Magnetization transfer between chemically equivalent but orientationally different 19F spins on different molecules reduces the 19F magnetization in an exchange experiment. At long mixing times, the equilibrium 19F magnetization is 1/M, where M is the number of orientationally different molecules in the aggregate. The use of the 19F spin increases the homonuclear dipolar coupling and thus the distance reach. We demonstrate this technique on crystalline model compounds with known numbers of molecules in the asymmetric unit cell, and show that 19F spin diffusion is more efficient than that of 13C by a factor of approximately 500. Application to a beta-hairpin antimicrobial peptide, protegrin-1, shows that the peptide is almost completely dimerized in POPC bilayers at a concentration of 7.4 mol %. Decreasing the peptide concentration reduced the dimer fraction. Using a monomer-dimer equilibrium model, we estimate the DeltaG for dimer formation to be -10.2 +/- 2.3 kJ/mol. This is in good agreement with the previously measured free energy reduction for partitioning and aggregating beta-sheet peptides into phospholipid membranes. This 19F spin diffusion technique opens the possibility of determining the oligomeric structures of membrane peptides.
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Affiliation(s)
- Jarrod J Buffy
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
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