1
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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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2
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Bjornson-Hooper ZB, Fragiadakis GK, Spitzer MH, Chen H, Madhireddy D, Hu K, Lundsten K, McIlwain DR, Nolan GP. A Comprehensive Atlas of Immunological Differences Between Humans, Mice, and Non-Human Primates. Front Immunol 2022; 13:867015. [PMID: 35359965 PMCID: PMC8962947 DOI: 10.3389/fimmu.2022.867015] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 02/16/2022] [Indexed: 01/01/2023] Open
Abstract
Animal models are an integral part of the drug development and evaluation process. However, they are unsurprisingly imperfect reflections of humans, and the extent and nature of many immunological differences are unknown. With the rise of targeted and biological therapeutics, it is increasingly important that we understand the molecular differences in the immunological behavior of humans and model organisms. However, very few antibodies are raised against non-human primate antigens, and databases of cross-reactivity between species are incomplete. Thus, we screened 332 antibodies in five immune cell populations in blood from humans and four non-human primate species generating a comprehensive cross-reactivity catalog that includes cell type-specificity. We used this catalog to create large mass cytometry universal cross-species phenotyping and signaling panels for humans, along with three of the model organisms most similar to humans: rhesus and cynomolgus macaques and African green monkeys; and one of the mammalian models most widely used in drug development: C57BL/6 mice. As a proof-of-principle, we measured immune cell signaling responses across all five species to an array of 15 stimuli using mass cytometry. We found numerous instances of different cellular phenotypes and immune signaling events occurring within and between species, and detailed three examples (double-positive T cell frequency and signaling; granulocyte response to Bacillus anthracis antigen; and B cell subsets). We also explore the correlation of herpes simian B virus serostatus on the immune profile. Antibody panels and the full dataset generated are available online as a resource to enable future studies comparing immune responses across species during the evaluation of therapeutics.
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Affiliation(s)
| | - Gabriela K. Fragiadakis
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, United States
- Department of Medicine, Division of Rheumatology, University of California San Francisco, San Francisco, CA, United States
- Bakar ImmunoX Initiative, University of California San Francisco, San Francisco, CA, United States
- University of California, San Francisco (UCSF) Data Science CoLab and University of California, San Francisco (UCSF) Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Matthew H. Spitzer
- Immunology Program, Stanford University, Stanford, CA, United States
- Departments of Otolaryngology – Head and Neck Surgery and Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, United States
- Parker Institute for Cancer Immunotherapy, San Francisco, CA, United States
- Chan Zuckerberg Biohub, San Francisco, CA, United States
| | - Han Chen
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, United States
| | - Deepthi Madhireddy
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, United States
| | - Kevin Hu
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, United States
| | - Kelly Lundsten
- BioLegend Inc, Advanced Cytometry, San Diego, CA, United States
| | - David R. McIlwain
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, United States
| | - Garry P. Nolan
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, United States
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3
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Abstract
Severe illness caused by coronavirus disease 2019 (COVID-19) is characterized by an overexuberant inflammatory response resulting in acute respiratory distress syndrome (ARDS) and progressive respiratory failure (A. Gupta, M. V. Madhavan, K. Sehgal, N. Nair, et al., Nat Med 26:1017–1032, 2020, https://doi.org/10.1038/s41591-020-0968-3). Rhesus theta (θ) defensin-1 (RTD-1) is a macrocyclic host defense peptide exhibiting antimicrobial and immunomodulatory activities. RTD-1 treatment significantly improved survival in murine models of a severe acute respiratory syndrome (SARS-CoV-1) and endotoxin-induced acute lung injury (ALI) (C. L. Wohlford-Lenane, D. K. Meyerholz, S. Perlman, H. Zhou, et al., J Virol 83:11385–11390, 2009, https://doi.org/10.1128/JVI.01363-09; J. G. Jayne, T. J. Bensman, J. B. Schaal, A. Y. J. Park, et al., Am J Respir Cell Mol Biol 58:310–319, 2018, https://doi.org/10.1165/rcmb.2016-0428OC). This investigation aimed to characterize the preclinical pharmacokinetics (PK) and safety of intravenous (i.v.) RTD-1. Based on the lack of adverse findings, the no observed adverse effect level (NOAEL) was established at 10 mg/kg/day in rats and 15 mg/kg/day in monkeys. Analysis of single ascending dose studies in both species revealed greater-than-dose-proportional increases in the area under the curve extrapolated to infinity (AUC0-∞) (e.g., 8-fold increase from 5 mg/kg to 20 mg/kg in rats) suggestive of nonlinear PK. The volume of distribution at steady state (Vss) ranged between 550 and 1,461 mL/kg, indicating extensive tissue distribution, which was validated in a biodistribution study of [14C]RTD-1 in rats. Based on interspecies allometric scaling, the predicted human clearance and Vss are 6.48 L/h and 28.0 L, respectively, for an adult (70 kg). To achieve plasma exposures associated with therapeutic efficacy established in a murine model of ALI, the estimated human equivalent dose (HED) is between 0.36 and 0.83 mg/kg/day. The excellent safety profile demonstrated in these studies and the efficacy observed in the murine models support the clinical investigation of RTD-1 for treatment of COVID-19 or other pulmonary inflammatory diseases.
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4
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OUP accepted manuscript. Med Mycol 2022; 60:6526320. [PMID: 35142862 PMCID: PMC8929677 DOI: 10.1093/mmy/myac008] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/13/2021] [Accepted: 02/01/2022] [Indexed: 11/23/2022] Open
Abstract
Candida auris is an emerging, multi drug resistant fungal pathogen that has caused infectious outbreaks in over 45 countries since its first isolation over a decade ago, leading to in-hospital crude mortality rates as high as 72%. The fungus is also acclimated to disinfection procedures and persists for weeks in nosocomial ecosystems. Alarmingly, the outbreaks of C. auris infections in Coronavirus Disease-2019 (COVID-19) patients have also been reported. The pathogenicity, drug resistance and global spread of C. auris have led to an urgent exploration of novel, candidate antifungal agents for C. auris therapeutics. This narrative review codifies the emerging data on the following new/emerging antifungal compounds and strategies: antimicrobial peptides, combinational therapy, immunotherapy, metals and nano particles, natural compounds, and repurposed drugs. Encouragingly, a vast majority of these exhibit excellent anti- C. auris properties, with promising drugs now in the pipeline in various stages of development. Nevertheless, further research on the modes of action, toxicity, and the dosage of the new formulations are warranted. Studies are needed with representation from all five C. auris clades, so as to produce data of grater relevance, and broader significance and validity.
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5
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Skeate JG, Segerink WH, Garcia MD, Fernandez DJ, Prins R, Lühen KP, Voss FO, Da Silva DM, Kast WM. Theta-Defensins Inhibit High-Risk Human Papillomavirus Infection Through Charge-Driven Capsid Clustering. Front Immunol 2020; 11:561843. [PMID: 33154746 PMCID: PMC7586039 DOI: 10.3389/fimmu.2020.561843] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/24/2020] [Indexed: 11/26/2022] Open
Abstract
Persistent infection with high-risk human papillomavirus (hrHPV) genotypes results in a large number of anogenital and head and neck cancers worldwide. Although prophylactic vaccination coverage has improved, there remains a need to develop methods that inhibit viral transmission toward preventing the spread of HPV-driven disease. Defensins are a class of innate immune effector peptides that function to protect hosts from infection by pathogens such as viruses and bacteria. Previous work utilizing α and β defensins from humans has demonstrated that the α-defensin HD5 is effective at inhibiting the most common high-risk genotype, HPV16. A third class of defensin that has yet to be explored are θ-defensins: small, 18-amino acid cyclic peptides found in old-world monkeys whose unique structure makes them both highly cationic and resistant to degradation. Here we show that the prototype θ-defensin, rhesus theta defensin 1, inhibits hrHPV infection through a mechanism involving capsid clustering that inhibits virions from binding to cell surface receptor complexes.
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Affiliation(s)
- Joseph G Skeate
- Department of Molecular Microbiology & Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Wouter H Segerink
- Department of Molecular Microbiology & Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Mauricio D Garcia
- Department of Molecular Microbiology & Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Daniel J Fernandez
- Department of Molecular Microbiology & Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Ruben Prins
- Department of Molecular Microbiology & Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Kim P Lühen
- Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, United States
| | - Féline O Voss
- Department of Molecular Microbiology & Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Diane M Da Silva
- Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, United States.,Department of Obstetrics and Gynecology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - W Martin Kast
- Department of Molecular Microbiology & Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.,Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, United States.,Department of Obstetrics and Gynecology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
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6
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Basso V, Tran DQ, Ouellette AJ, Selsted ME. Host Defense Peptides as Templates for Antifungal Drug Development. J Fungi (Basel) 2020; 6:jof6040241. [PMID: 33113935 PMCID: PMC7711597 DOI: 10.3390/jof6040241] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 12/15/2022] Open
Abstract
Current treatment for invasive fungal diseases is limited to three classes of antifungal drugs: azoles, polyenes, and echinocandins. The most recently introduced antifungal class, the echinocandins, was first approved nearly 30 years ago. The limited antifungal drug portfolio is rapidly losing its clinical utility due to the inexorable rise in the incidence of invasive fungal infections and the emergence of multidrug resistant (MDR) fungal pathogens. New antifungal therapeutic agents and novel approaches are desperately needed. Here, we detail attempts to exploit the antifungal and immunoregulatory properties of host defense peptides (HDPs) in the design and evaluation of new antifungal therapeutics and discuss historical limitations and recent advances in this quest.
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Affiliation(s)
- Virginia Basso
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA; (V.B.); (D.Q.T.); (A.J.O.)
| | - Dat Q. Tran
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA; (V.B.); (D.Q.T.); (A.J.O.)
- Oryn Therapeutics, Vacaville, CA 95688, USA
| | - André J. Ouellette
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA; (V.B.); (D.Q.T.); (A.J.O.)
- Norris Comprehensive Cancer Center of the University of Southern California, Los Angeles, CA 90089, USA
| | - Michael E. Selsted
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA; (V.B.); (D.Q.T.); (A.J.O.)
- Oryn Therapeutics, Vacaville, CA 95688, USA
- Norris Comprehensive Cancer Center of the University of Southern California, Los Angeles, CA 90089, USA
- Correspondence:
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7
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Fernández de Ullivarri M, Arbulu S, Garcia-Gutierrez E, Cotter PD. Antifungal Peptides as Therapeutic Agents. Front Cell Infect Microbiol 2020; 10:105. [PMID: 32257965 PMCID: PMC7089922 DOI: 10.3389/fcimb.2020.00105] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 02/27/2020] [Indexed: 12/17/2022] Open
Abstract
Fungi have been used since ancient times in food and beverage-making processes and, more recently, have been harnessed for the production of antibiotics and in processes of relevance to the bioeconomy. Moreover, they are starting to gain attention as a key component of the human microbiome. However, fungi are also responsible for human infections. The incidence of community-acquired and nosocomial fungal infections has increased considerably in recent decades. Antibiotic resistance development, the increasing number of immunodeficiency- and/or immunosuppression-related diseases and limited therapeutic options available are triggering the search for novel alternatives. These new antifungals should be less toxic for the host, with targeted or broader antimicrobial spectra (for diseases of known and unknown etiology, respectively) and modes of actions that limit the potential for the emergence of resistance among pathogenic fungi. Given these criteria, antimicrobial peptides with antifungal properties, i.e., antifungal peptides (AFPs), have emerged as powerful candidates due to their efficacy and high selectivity. In this review, we provide an overview of the bioactivity and classification of AFPs (natural and synthetic) as well as their mode of action and advantages over current antifungal drugs. Additionally, natural, heterologous and synthetic production of AFPs with a view to greater levels of exploitation is discussed. Finally, we evaluate the current and potential applications of these peptides, along with the future challenges relating to antifungal treatments.
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Affiliation(s)
- Miguel Fernández de Ullivarri
- APC Microbiome Ireland, University College Cork, Cork, Ireland.,Food Bioscience Department, Teagasc Food Research Centre, Fermoy, Ireland
| | - Sara Arbulu
- APC Microbiome Ireland, University College Cork, Cork, Ireland.,Food Bioscience Department, Teagasc Food Research Centre, Fermoy, Ireland
| | - Enriqueta Garcia-Gutierrez
- Food Bioscience Department, Teagasc Food Research Centre, Fermoy, Ireland.,Gut Microbes and Health, Quadram Institute Bioscience, Norwich, United Kingdom
| | - Paul D Cotter
- APC Microbiome Ireland, University College Cork, Cork, Ireland.,Food Bioscience Department, Teagasc Food Research Centre, Fermoy, Ireland
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8
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Tongaonkar P, Punj V, Subramanian A, Tran DQ, Trinh KK, Schaal JB, Laragione T, Ouellette AJ, Gulko PS, Selsted ME. RTD-1 therapeutically normalizes synovial gene signatures in rat autoimmune arthritis and suppresses proinflammatory mediators in RA synovial fibroblasts. Physiol Genomics 2019; 51:657-667. [PMID: 31762409 DOI: 10.1152/physiolgenomics.00066.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Rhesus theta defensin-1 (RTD-1), a macrocyclic immunomodulatory host defense peptide from Old World monkeys, is therapeutic in pristane-induced arthritis (PIA) in rats, a model of rheumatoid arthritis (RA). RNA-sequence (RNA-Seq) analysis was used to interrogate the changes in gene expression in PIA rats, which identified 617 differentially expressed genes (DEGs) in PIA synovial tissue of diseased rats. Upstream regulator analysis showed upregulation of gene expression pathways regulated by TNF, IL1B, IL6, proinflammatory cytokines, and matrix metalloproteases (MMPs) involved in RA. In contrast, ligand-dependent nuclear receptors like the liver X-receptors NR1H2 and NR1H3 and peroxisome proliferator-activated receptor gamma (PPARG) were downregulated in arthritic synovia. Daily RTD-1 treatment of PIA rats for 1-5 days following disease presentation modulated 340 of the 617 disease genes, and synovial gene expression in PIA rats treated 5 days with RTD-1 closely resembled the gene signature of naive synovium. Systemic RTD-1 inhibited proinflammatory upstream regulators such as TNF, IL1, and IL6 and activated antiarthritic ligand-dependent nuclear receptor pathways, including PPARG, NR1H2, and NR1H3, that were suppressed in untreated PIA rats. RTD-1 also inhibited proinflammatory responses in IL-1β-stimulated human RA fibroblast-like synoviocytes (FLS) in vitro and diminished expression of human orthologs of disease genes that are induced in rat PIA synovium. Thus, the antiarthritic mechanisms of systemic RTD-1 include homeostatic regulation of arthritogenic gene networks in a manner that correlates temporally with clinical resolution of rat PIA.
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Affiliation(s)
- Prasad Tongaonkar
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Vasu Punj
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Akshay Subramanian
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Dat Q Tran
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California.,Oryn Therapeutics, LLC, Vacaville, California
| | - Katie K Trinh
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Justin B Schaal
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Teresina Laragione
- Division of Rheumatology, Department of Medicine, Icahn School of Medicine at Mt. Sinai, New York, New York and
| | - André J Ouellette
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California.,USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Percio S Gulko
- Division of Rheumatology, Department of Medicine, Icahn School of Medicine at Mt. Sinai, New York, New York and
| | - Michael E Selsted
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California.,Oryn Therapeutics, LLC, Vacaville, California.,USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California
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9
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Jayne JG, Bensman TJ, Schaal JB, Park AYJ, Kimura E, Tran D, Selsted ME, Beringer PM. Rhesus θ-Defensin-1 Attenuates Endotoxin-induced Acute Lung Injury by Inhibiting Proinflammatory Cytokines and Neutrophil Recruitment. Am J Respir Cell Mol Biol 2018; 58:310-319. [PMID: 28954201 DOI: 10.1165/rcmb.2016-0428oc] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Acute lung injury (ALI) is a clinical syndrome characterized by acute respiratory failure and is associated with substantial morbidity and mortality. Rhesus θ-defensin (RTD)-1 is an antimicrobial peptide with immunomodulatory activity. As airway inflammation and neutrophil recruitment and activation are hallmarks of ALI, we evaluated the therapeutic efficacy of RTD-1 in preclinical models of the disease. We investigated the effect of RTD-1 on neutrophil chemotaxis and macrophage-driven pulmonary inflammation with human peripheral neutrophils and LPS-stimulated murine alveolar macrophage (denoted MH-S) cells. Treatment and prophylactic single escalating doses were administered subcutaneously in a well-established murine model of direct endotoxin-induced ALI. We assessed lung injury by histopathology, pulmonary edema, inflammatory cell recruitment, and inflammatory cytokines/chemokines in the BAL fluid. In vitro studies demonstrated that RTD-1 suppressed CXCL8-induced neutrophil chemotaxis, TNF-mediated neutrophil-endothelial cell adhesion, and proinflammatory cytokine release in activated murine alveolar immortalized macrophages (MH-S) cells. Treatment with RTD-1 significantly inhibited in vivo LPS-induced ALI by reducing pulmonary edema and histopathological changes. Treatment was associated with dose- and time-dependent inhibition of proinflammatory cytokines (TNF, IL-1β, and IL-6), peroxidase activity, and neutrophil recruitment into the airways. Antiinflammatory effects were demonstrated in animals receiving RTD-1 up to 12 hours after LPS challenge. Notably, subcutaneously administered RTD-1 demonstrates good peptide stability as demonstrated by the long in vivo half-life. Taken together, these studies demonstrate that RTD-1 is efficacious in an experimental model of ALI through inhibition of neutrophil chemotaxis and adhesion, and the attenuation of proinflammatory cytokines and gene expression from alveolar macrophages.
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Affiliation(s)
| | | | - Justin B Schaal
- 2 Keck School of Medicine, University of Southern California, Los Angeles, California; and
| | | | - Elza Kimura
- 3 State University of Maringá, Maringá, Paraná, Brazil
| | - Dat Tran
- 2 Keck School of Medicine, University of Southern California, Los Angeles, California; and
| | - Michael E Selsted
- 2 Keck School of Medicine, University of Southern California, Los Angeles, California; and
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10
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Fungicidal Potency and Mechanisms of θ-Defensins against Multidrug-Resistant Candida Species. Antimicrob Agents Chemother 2018; 62:AAC.00111-18. [PMID: 29610196 DOI: 10.1128/aac.00111-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 03/26/2018] [Indexed: 12/24/2022] Open
Abstract
Systemic candidiasis is a growing health care concern that is becoming even more challenging due to the growing frequency of infections caused by multidrug-resistant (MDR) Candida species. Thus, there is an urgent need for new therapeutic approaches to candidiasis, including strategies bioinspired by insights into natural host defense against fungal pathogens. The antifungal properties of θ-defensins, macrocyclic peptides expressed in tissues of Old World monkeys, were investigated against a panel of drug-sensitive and drug-resistant clinical isolates of Candida albicans and non-albicans Candida species. Rhesus θ-defensin 1 (RTD-1), the prototype θ-defensin, was rapidly and potently fungicidal against drug-sensitive and MDR C. albicans strains. Fungal killing occurred by cell permeabilization that was temporally correlated with ATP release and intracellular accumulation of reactive oxygen species (ROS). Killing by RTD-1 was compared with that by histatin 5 (Hst 5), an extensively characterized anticandidal peptide expressed in human saliva. RTD-1 killed C. albicans much more rapidly and at a >200-fold lower concentration than that of Hst 5. Unlike Hst 5, the anticandidal activity of RTD-1 was independent of mitochondrial ATP production. Moreover, RTD-1 was completely resistant to Candida proteases for 2 h under conditions that rapidly and completely degraded Hst 5. MICs and minimum fungicidal concentrations (MFCs) of 14 natural θ-defensins isoforms against drug-resistant C. albicans isolates identified peptides that are more active than amphotericin B and/or caspofungin against fluconazole-resistant organisms, including MDR Candida auris. These results point to the potential of macrocyclic θ-defensins as structural templates for the design of antifungal therapeutics.
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11
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Zhang RY, Thapa P, Espiritu MJ, Menon V, Bingham JP. From nature to creation: Going around in circles, the art of peptide cyclization. Bioorg Med Chem 2018; 26:1135-1150. [DOI: 10.1016/j.bmc.2017.11.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 11/06/2017] [Accepted: 11/09/2017] [Indexed: 02/02/2023]
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12
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Affiliation(s)
- Sylvia Knapp
- Department of Medicine 1Medical University of ViennaVienna, Austria
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13
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Schaal JB, Maretzky T, Tran DQ, Tran PA, Tongaonkar P, Blobel CP, Ouellette AJ, Selsted ME. Macrocyclic θ-defensins suppress tumor necrosis factor-α (TNF-α) shedding by inhibition of TNF-α-converting enzyme. J Biol Chem 2018; 293:2725-2734. [PMID: 29317500 DOI: 10.1074/jbc.ra117.000793] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 01/03/2018] [Indexed: 12/16/2022] Open
Abstract
Theta-defensins (θ-defensins) are macrocyclic peptides expressed exclusively in granulocytes and selected epithelia of Old World monkeys. They contribute to anti-pathogen host defense responses by directly killing a diverse range of microbes. Of note, θ-defensins also modulate microbe-induced inflammation by affecting the production of soluble tumor necrosis factor (sTNF) and other proinflammatory cytokines. Here, we report that natural rhesus macaque θ-defensin (RTD) isoforms regulate sTNF cellular release by inhibiting TNF-α-converting enzyme (TACE; also known as adisintegrin and metalloprotease 17; ADAM17), the primary pro-TNF sheddase. Dose-dependent inhibition of cellular TACE activity by RTDs occurred when leukocytes were stimulated with live Escherichia coli cells as well as numerous Toll-like receptor agonists. Moreover, the relative inhibitory potencies of the RTD isoforms strongly correlated with their suppression of TNF release by stimulated blood leukocytes and THP-1 monocytes. RTD isoforms also inhibited ADAM10, a sheddase closely related to TACE. TACE inhibition was abrogated by introducing a single opening in the RTD-1 backbone, demonstrating that the intact macrocycle is required for enzyme inhibition. Enzymologic analyses showed that RTD-1 is a fast binding, reversible, non-competitive inhibitor of TACE. We conclude that θ-defensin-mediated inhibition of pro-TNF proteolysis by TACE represents a rapid mechanism for the regulation of sTNF and TNF-dependent inflammatory pathways. Molecules with structural and functional features mimicking those of θ-defensins may have clinical utility as TACE inhibitors for managing TNF-driven diseases.
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Affiliation(s)
- Justin B Schaal
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90089
| | - Thorsten Maretzky
- Hospital for Special Surgery, Weill Cornell Medicine, New York, New York 10021; Inflammation Program and Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Dat Q Tran
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90089
| | - Patti A Tran
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90089
| | - Prasad Tongaonkar
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90089
| | - Carl P Blobel
- Hospital for Special Surgery, Weill Cornell Medicine, New York, New York 10021
| | - André J Ouellette
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90089; Norris Comprehensive Cancer Center of the University of Southern California, Los Angeles, California 90033
| | - Michael E Selsted
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90089; Norris Comprehensive Cancer Center of the University of Southern California, Los Angeles, California 90033.
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14
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In-cell production of a genetically-encoded library based on the θ-defensin RTD-1 using a bacterial expression system. Bioorg Med Chem 2017; 26:1212-1219. [PMID: 28927803 DOI: 10.1016/j.bmc.2017.09.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/01/2017] [Accepted: 09/05/2017] [Indexed: 02/08/2023]
Abstract
We report the high-yield heterologous expression of bioactive θ-defensin RTD-1 inside Escherichia coli cells by making use of intracellular protein trans-splicing in combination with a high efficient split-intein. RTD-1 is a small backbone-cyclized polypeptide with three disulfide bridges and a natural inhibitor of anthrax lethal factor protease. Recombinant RTD-1 was natively folded and able to inhibit anthrax lethal factor protease. In-cell expression of RTD-1 was very efficient and yielded ≈0.7mg of folded RTD-1 per gram of wet E. coli cells. This approach was used to generate of a genetically-encoded RTD-1-based peptide library in live E. coli cells. These results clearly demonstrate the possibility of using genetically-encoded RTD-1-based peptide libraries in live E. coli cells, which is a critical first step for developing in-cell screening and directed evolution technologies using the cyclic peptide RTD-1asa molecular scaffold.
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15
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The Role of Defensins in HIV Pathogenesis. Mediators Inflamm 2017; 2017:5186904. [PMID: 28839349 PMCID: PMC5559915 DOI: 10.1155/2017/5186904] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/24/2017] [Indexed: 02/08/2023] Open
Abstract
Profound loss of CD4+ T cells, progressive impairment of the immune system, inflammation, and sustained immune activation are the characteristics of human immunodeficiency virus-1 (HIV-1) infection. Innate immune responses respond immediately from the day of HIV infection, and a thorough understanding of the interaction between several innate immune cells and HIV-1 is essential to determine to what extent those cells play a crucial role in controlling HIV-1 in vivo. Defensins, divided into the three subfamilies α-, β-, and θ-defensins based on structure and disulfide linkages, comprise a critical component of the innate immune response and exhibit anti-HIV-1 activities and immunomodulatory capabilities. In humans, only α- and β-defensins are expressed in various tissues and have broad impacts on HIV-1 transmission, replication, and disease progression. θ-defensins have been identified as functional peptides in Old World monkeys, but not in humans. Instead, θ-defensins exist only as pseudogenes in humans, chimpanzees, and gorillas. The use of the synthetic θ-defensin peptide “retrocyclin” as an antiviral therapy was shown to be promising, and further research into the development of defensin-based HIV-1 therapeutics is needed. This review focuses on the role of defensins in HIV-1 pathogenesis and highlights future research efforts that warrant investigation.
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16
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Efficacy of Rhesus Theta-Defensin-1 in Experimental Models of Pseudomonas aeruginosa Lung Infection and Inflammation. Antimicrob Agents Chemother 2017; 61:AAC.00154-17. [PMID: 28559270 DOI: 10.1128/aac.00154-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 05/21/2017] [Indexed: 12/19/2022] Open
Abstract
Chronic airway infection and inflammation contribute to the progressive loss of lung function and shortened survival of patients with cystic fibrosis (CF). Rhesus theta defensin-1 (RTD-1) is a macrocyclic host defense peptide with antimicrobial and immunomodulatory activities. Combined with favorable preclinical safety and peptide stability data, RTD-1 warrants investigation to determine its therapeutic potential for treatment of CF lung disease. We sought to evaluate the therapeutic potential of RTD-1 for CF airway infection and inflammation using in vitro, ex vivo, and in vivo models. We evaluated RTD-1's effects on basal and Pseudomonas aeruginosa-induced inflammation in CF sputum leukocytes and CF bronchial epithelial cells. Peptide stability was evaluated by incubation with CF sputum. Airway pharmacokinetics, safety, and tolerance studies were performed in naive mice. Aerosolized RTD-1 treatment effects were assessed by analyzing lung bacterial burdens and airway inflammation using an established model of chronic P. aeruginosa endobronchial infection in CF (ΔF508) mice. RTD-1 directly reduces metalloprotease activity, as well as inflammatory cytokine secretion from CF airway leukocyte and bronchial epithelial cells. Intrapulmonary safety, tolerability, and stability data support the aerosol administration route. RTD-1 reduced the bacterial lung burden, airway neutrophils, and inflammatory cytokines in CF mice with chronic P. aeruginosa lung infection. Collectively, these studies support further development of RTD-1 for treatment of CF airway disease.
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17
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Ali H. Emerging Roles for MAS-Related G Protein-Coupled Receptor-X2 in Host Defense Peptide, Opioid, and Neuropeptide-Mediated Inflammatory Reactions. Adv Immunol 2017; 136:123-162. [PMID: 28950944 DOI: 10.1016/bs.ai.2017.06.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mast cells (MCs) are tissue-resident immune cells that contribute to host defense but are best known for their roles in allergic and inflammatory diseases. In humans, MCs are divided into two subtypes based on the protease content of their secretory granules. Thus, human lung MCs contain only tryptase and are known as MCT, whereas skin MCs contain both tryptase and chymase and are known as MCTC. Patients with severe asthma display elevated MCs in the lung, which undergo phenotypic change from MCT to MCTC. Although the human genome contains four Mas related G protein coupled receptor X (MRGPRX) genes, an important feature of MCTC is that they selectively express MRGPRX2. It is activated by antimicrobial host defense peptides such as human β-defensins and the cathelicidin LL-37 and likely contributes to host defense. MRGPRX2 is also a receptor for the neuropeptide substance P, major basic protein, eosinophil peroxidase, opioids, and many FDA-approved cationic drugs. Increased expression of MRGPRX2 or enhanced downstream signaling likely contributes to chronic inflammatory diseases such as rosacea, atopic dermatitis, chronic urticaria, and severe asthma. In this chapter, I will discuss the expression profile and function of MRGPRX1-4 and review the emerging roles of MRGPRX2 on host defense, chronic inflammatory diseases, and drug-induced pseudoallergic reactions. I will also examine the novel aspects of MRGPRX2 signaling in MCs as it related to degranulation and review the mechanisms of its regulation.
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Affiliation(s)
- Hydar Ali
- University of Pennsylvania School of Dental Medicine, Philadelphia, PA, United States.
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18
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Li Y, Gould A, Aboye T, Bi T, Breindel L, Shekhtman A, Camarero JA. Full Sequence Amino Acid Scanning of θ-Defensin RTD-1 Yields a Potent Anthrax Lethal Factor Protease Inhibitor. J Med Chem 2017; 60:1916-1927. [PMID: 28151653 DOI: 10.1021/acs.jmedchem.6b01689] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
θ-Defensin RTD-1 is a noncompetitive inhibitor of anthrax lethal factor (LF) protease (IC50 = 390 ± 20 nM, Ki = 365 ± 20 nM) and a weak inhibitor of other mammalian metalloproteases such as TNFα converting enzyme (TACE) (Ki = 4.45 ± 0.48 μM). Using full sequence amino acid scanning in combination with a highly efficient "one-pot" cyclization-folding approach, we obtained an RTD-1-based peptide that was around 10 times more active than wild-type RTD-1 in inhibiting LF protease (IC50 = 43 ± 3 nM, Ki = 18 ± 1 nM). The most active peptide was completely symmetrical, rich in Arg and Trp residues, and able to adopt a native RTD-1-like structure. These results show the power of optimized chemical peptide synthesis approaches for the efficient production of libraries of disulfide-rich backbone-cyclized peptides to quickly perform structure-activity relationship studies for optimizing protease inhibitors.
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Affiliation(s)
| | | | | | | | - Leonard Breindel
- Department of Chemistry, State University of New York , Albany, New York 12222, United States
| | - Alexander Shekhtman
- Department of Chemistry, State University of New York , Albany, New York 12222, United States
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19
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Strzelecka P, Czaplinska D, Sadej R, Wardowska A, Pikula M, Lesner A. Simplified, serine-rich theta-defensin analogues as antitumour peptides. Chem Biol Drug Des 2017; 90:52-63. [PMID: 28004513 DOI: 10.1111/cbdd.12927] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 12/05/2016] [Accepted: 12/10/2016] [Indexed: 01/15/2023]
Abstract
θ-defensins belong to the family of host defence peptides. They are the only known example of cyclic polypeptides in animal proteomes. This study presents the synthesis of simplified θ-defensin analogues with pairs of cysteine replaced either by alanine, leucine or serine residues. Cytotoxicity tests were performed on human mammary epithelial (HB2) and breast cancer (SKBR3, MDA-MB-231) cell lines to determine whether peptides are selectively targeting cancer cells. The effect of these peptides was also evaluated in 3D Matrigel cultures, which are based on extracellular matrix components and therefore closely represent in vivo conditions. Finally, to determine whether analogues are able to sensitize MDA-MB-231 triple-negative breast cancer cells to chemotherapeutics, we co-administrated peptides with cisplatin or doxorubicin hydrochloride also in 3D Matrigel cultures. Additionally, cytotoxicity towards peripheral blood mononuclear cells and haemolytic effect were examined for a chosen representative of synthesized compounds. The results showed that positively charged serine-containing θ-defensin derivatives were more cytotoxic towards breast cancer cells (SKBR3, MDA-MB-231) than towards mammary epithelial cells (HB2). Analogues enhanced the effect of cisplatin and doxorubicin hydrochloride on triple-negative breast cancer cell line (MDA-MB-231).
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Affiliation(s)
- Paulina Strzelecka
- Department of Molecular Biochemistry, Faculty of Chemistry, University of Gdansk, Gdansk, Poland
| | - Dominika Czaplinska
- Department of Medical Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Rafal Sadej
- Department of Medical Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Anna Wardowska
- Department of Clinical Immunology and Transplantology, Medical University of Gdansk, Gdansk, Poland
| | - Michal Pikula
- Department of Clinical Immunology and Transplantology, Medical University of Gdansk, Gdansk, Poland
| | - Adam Lesner
- Department of Molecular Biochemistry, Faculty of Chemistry, University of Gdansk, Gdansk, Poland
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20
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Gupta K, Kotian A, Subramanian H, Daniell H, Ali H. Activation of human mast cells by retrocyclin and protegrin highlight their immunomodulatory and antimicrobial properties. Oncotarget 2016; 6:28573-87. [PMID: 26378047 PMCID: PMC4745678 DOI: 10.18632/oncotarget.5611] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Accepted: 08/30/2015] [Indexed: 01/21/2023] Open
Abstract
Preclinical evaluation of Retrocyclins (RC-100, RC-101) and Protegrin-1 (PG-1) antimicrobial peptides (AMPs) is important because of their therapeutic potential against bacterial, fungal and viral infections. Human mast cells (HMCs) play important roles in host defense and wound healing but the abilities of retrocyclins and protegrin-1 to harness these functions have not been investigated. Here, we report that chemically synthesized RC-100 and PG-1 caused calcium mobilization and degranulation in HMCs but these responses were not blocked by an inhibitor of formyl peptide receptor-like 1 (FPRL1), a known receptor for AMPs. However, RC-100 and PG-1 induced degranulation in rat basophilic leukemia (RBL-2H3) cells stably expressing Mas related G protein coupled receptor X2 (MrgX2). Chemical synthesis of these AMPs is prohibitively expensive and post-synthesis modifications (cyclization, disulfide bonds, folding) are inadequate for optimal antimicrobial activity. Indeed, we found that synthetic RC-100, which caused mast cell degranulation via MrgX2, did not display any antimicrobial activity. Green-fluorescent protein (GFP)-tagged RC-101 (analog of RC-100) and GFP-tagged PG-1 purified from transgenic plant chloroplasts killed bacteria and induced mast cell degranulation. Furthermore, GFP-PG1 bound specifically to RBL-2H3 cells expressing MrgX2. These findings suggest that retrocyclins and protegrins activate HMCs independently of FPRL1 but via MrgX2. Harnessing this novel feature of AMPs to activate mast cell's host defense/wound healing properties in addition to their antimicrobial activities expands their clinical potential. Low cost production of AMPs in plants should facilitate their advancement to the clinic overcoming major hurdles in current production systems.
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Affiliation(s)
- Kshitij Gupta
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Akhil Kotian
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Hariharan Subramanian
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Henry Daniell
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Hydar Ali
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
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21
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Knyght I, Clifton L, Saaka Y, Lawrence MJ, Barlow DJ. Interaction of the Antimicrobial Peptides Rhesus θ-Defensin and Porcine Protegrin-1 with Anionic Phospholipid Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:7403-10. [PMID: 27357217 DOI: 10.1021/acs.langmuir.6b01688] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A combination of Langmuir isotherm, Brewster angle microscopy (BAM), and neutron reflectivity studies have been performed to gain insight into the effects on model bacterial cell membranes of the antimicrobial peptides, Rhesus θ-defensin 1 (RTD-1), and porcine protegrin 1 (PG-1). The peptides were interacted with monolayers spread at the air-water interface and prepared from a 3:1 molar mixture of phosphatidylethanolamine and phosphatidylglycerol used to approximate the cell membranes of Gram positive bacteria. The Langmuir film balance measurements show that both peptides perturb the lipid monolayers causing an increase in surface pressure, and the BAM studies show that each results in the formation of small domains within the lipid films, around 5 μm diameter. The overall change in monolayer surface pressure caused by PG-1, however, is a little more pronounced than that due to RTD-1 (+8.5 mN·m(-1) vs +5.5 mN·m(-1)), and the rate of its initial interaction with the monolayer is a little more rapid than that for RTD-1. The neutron reflectivity studies also show differences for PG-1 and RTD-1, with the model fits to these data showing that the more amphiphilic PG-1 becomes fully embedded within the lipid film-causing an extension of the lipid acyl chains but leaving the thickness of the lipid headgroup layer unaffected-while RTD-1 is seen to insert less deeply-causing the same extension of the lipid acyl chains as PG-1 but also causing a significant increase in thickness of the lipid headgroup layer. The various differing effects of the two peptides on anionic lipid monolayers are discussed in the context of their differing hemolytic activities, and their proposed differing propensities to form transmembrane pores.
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Affiliation(s)
- Ivana Knyght
- Institute of Pharmaceutical Science, King's College London , London SE1 9NH, United Kingdom
| | - Luke Clifton
- Rutherford Appleton Laboratory, ISIS Spallation Neutron Source, Harwell OX11 0QX, United Kingdom
| | - Yussif Saaka
- Institute of Pharmaceutical Science, King's College London , London SE1 9NH, United Kingdom
| | - M Jayne Lawrence
- Institute of Pharmaceutical Science, King's College London , London SE1 9NH, United Kingdom
| | - David J Barlow
- Institute of Pharmaceutical Science, King's College London , London SE1 9NH, United Kingdom
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22
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A synthetic antimicrobial peptide BTD-S expressed in Arabidopsis thaliana confers enhanced resistance to Verticillium dahliae. Mol Genet Genomics 2016; 291:1647-61. [PMID: 27138919 DOI: 10.1007/s00438-016-1209-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 04/19/2016] [Indexed: 12/13/2022]
Abstract
BTD-S is a synthetic non-cyclic θ-defensin derivative which was previously designed in our laboratory based on baboon θ-defensins (BTDs). It shows robust antimicrobial activity against economically important phytopathogen, Verticillium dahliae. Here, we deduced the coding nucleotide sequence of BTD-S and introduced the gene into wild-type (ecotype Columbia-0) Arabidopsis thaliana plants. Results demonstrated that BTD-S-transgenic lines displayed in bioassays inhibitory effects on the growth of V. dahliae in vivo and in vitro. Based on symptom severity, enhanced resistance was found in a survey of BTD-S-transgenic lines. Besides, crude protein extracts from root tissues of BTD-S-transformed plants significantly restricted the growth of fungal hyphae and the germination of conidia. Also, fungal biomass over time determined by real-time PCR demonstrated the overgrowth of V. dahliae in wild-type plants 2-3 weeks after inoculation, while almost no fungal DNA was detected in aerial tissues of their transgenic progenitors. The result suggested that fungus failed to invade and progress acropetally up to establish a systemic infection in BTD-S-transgenic plants. Moreover, the assessment of basal defense responses was performed in the leaves of WT and BTD-S-transgenic plants. The mitigated oxidative stress and low antioxidase level in BTD-S-transgenic plants revealed that BTD-S acts via permeabilizing target microbial membranes, which is in a category different from hypersensitive response-dependent defense. Taken together, our results demonstrate that BTD-S is a promising gene to be explored for transgenic engineering for plant protection against Verticillium wilt.
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23
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Wilmes M, Stockem M, Bierbaum G, Schlag M, Götz F, Tran DQ, Schaal JB, Ouellette AJ, Selsted ME, Sahl HG. Killing of staphylococci by θ-defensins involves membrane impairment and activation of autolytic enzymes. Antibiotics (Basel) 2016; 3:617-31. [PMID: 25632351 PMCID: PMC4306331 DOI: 10.3390/antibiotics3040617] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
θ-Defensins are cyclic antimicrobial peptides expressed in leukocytes of Old world monkeys. To get insight into their antibacterial mode of action, we studied the activity of RTDs (rhesus macaque θ-defensins) against staphylococci. We found that in contrast to other defensins, RTDs do not interfere with peptidoglycan biosynthesis, but rather induce bacterial lysis in staphylococci by interaction with the bacterial membrane and/or release of cell wall lytic enzymes. Potassium efflux experiments and membrane potential measurements revealed that the membrane impairment by RTDs strongly depends on the energization of the membrane. In addition, RTD treatment caused the release of Atl-derived cell wall lytic enzymes probably by interaction with membrane-bound lipoteichoic acid. Thus, the premature and uncontrolled activity of these enzymes contributes strongly to the overall killing by θ-defensins. Interestingly, a similar mode of action has been described for Pep5, an antimicrobial peptide of bacterial origin.
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Affiliation(s)
- Miriam Wilmes
- Institute of Medical Microbiology, Immunology and Parasitology, University of Bonn, 53105 Bonn, Germany; E-Mails: (M.S.); (G.B.); (H.-G.S.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +49-228-28711397
| | - Marina Stockem
- Institute of Medical Microbiology, Immunology and Parasitology, University of Bonn, 53105 Bonn, Germany; E-Mails: (M.S.); (G.B.); (H.-G.S.)
| | - Gabriele Bierbaum
- Institute of Medical Microbiology, Immunology and Parasitology, University of Bonn, 53105 Bonn, Germany; E-Mails: (M.S.); (G.B.); (H.-G.S.)
| | - Martin Schlag
- Interfaculty Institute of Microbiology and Infection Medicine, Microbial Genetics, University of Tübingen, 72076 Tübingen, Germany; E-Mails: (M.S.); (F.G.)
| | - Friedrich Götz
- Interfaculty Institute of Microbiology and Infection Medicine, Microbial Genetics, University of Tübingen, 72076 Tübingen, Germany; E-Mails: (M.S.); (F.G.)
| | - Dat Q. Tran
- Department of Pathology and Laboratory Medicine, USC Norris Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089-9601, USA; E-Mails: (D.Q.T.); (J.B.S.); (A.J.O.); (M.E.S.)
| | - Justin B. Schaal
- Department of Pathology and Laboratory Medicine, USC Norris Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089-9601, USA; E-Mails: (D.Q.T.); (J.B.S.); (A.J.O.); (M.E.S.)
| | - André J. Ouellette
- Department of Pathology and Laboratory Medicine, USC Norris Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089-9601, USA; E-Mails: (D.Q.T.); (J.B.S.); (A.J.O.); (M.E.S.)
| | - Michael E. Selsted
- Department of Pathology and Laboratory Medicine, USC Norris Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089-9601, USA; E-Mails: (D.Q.T.); (J.B.S.); (A.J.O.); (M.E.S.)
| | - Hans-Georg Sahl
- Institute of Medical Microbiology, Immunology and Parasitology, University of Bonn, 53105 Bonn, Germany; E-Mails: (M.S.); (G.B.); (H.-G.S.)
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24
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Reduction Impairs the Antibacterial Activity but Benefits the LPS Neutralization Ability of Human Enteric Defensin 5. Sci Rep 2016; 6:22875. [PMID: 26960718 PMCID: PMC4785407 DOI: 10.1038/srep22875] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 02/22/2016] [Indexed: 01/01/2023] Open
Abstract
Oxidized human defensin 5 (HD5OX), a Paneth cell-secreted antibacterial peptide with three characteristic disulfide bonds, protects the host from invasion by morbigenous microbes in the small intestine. HD5OX can be reduced by thioredoxin (Trx) in vitro, while the biochemical properties of the reduced linear peptide, HD5RED, remain unclear. Here, we first confirm that HD5RED does exist in vivo. Furthermore, we reveal that the recruitment of HD5RED to the outer membrane of Gram-negative bacteria and to the anionic lipid A is lower than that of HD5OX, and HD5RED is less efficient in penetrating bacterial outer and inner membranes and inducing membrane depolarization, which confers an attenuated antibacterial activity to HD5RED. However, due to its higher structural flexibility, the binding of HD5RED to bacterial lipopolysaccharide (LPS) is markedly stronger than that of HD5OX. Consequently, HD5RED is more effective in suppressing the production of the pro-inflammatory cytokine TNF-α in LPS-stimulated macrophages by blocking the interaction between LPS and LPS-binding protein, thus suggesting that HD5RED might act as a scavenger to neutralize LPS in the gut. This study provides insights into the antibacterial and immunoregulatory effects of HD5RED and expands the known repertoire of the enteric defensins.
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25
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Epand RM. Antiviral Host Defence Peptides. HOST DEFENSE PEPTIDES AND THEIR POTENTIAL AS THERAPEUTIC AGENTS 2016. [PMCID: PMC7123656 DOI: 10.1007/978-3-319-32949-9_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The ongoing global mortality and morbidity associated with viral pathogens highlights the need for the continued development of effective, novel antiviral molecules. The antiviral activity of cationic host defence peptides is of significant interest as novel therapeutics for treating viral infection and predominantly due to their broad spectrum antiviral activity. These peptides also display powerful immunomodulatory activity and are key mediators of inflammation. Therefore, they offer a significant opportunity to inform the development of novel therapeutics for treating viral infections by either directly targeting the pathogen or by enhancing the innate immune response. In this chapter, we review the antiviral activity of cathelicidins and defensins, and examine the potential for these peptides to be used as novel antiviral agents.
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Affiliation(s)
- Richard M. Epand
- Health Sciences Centre, McMaster University, Hamilton, Ontario Canada
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26
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Hayden RM, Goldberg GK, Ferguson BM, Schoeneck MW, Libardo MDJ, Mayeux SE, Shrestha A, Bogardus KA, Hammer J, Pryshchep S, Lehman HK, McCormick ML, Blazyk J, Angeles-Boza AM, Fu R, Cotten ML. Complementary Effects of Host Defense Peptides Piscidin 1 and Piscidin 3 on DNA and Lipid Membranes: Biophysical Insights into Contrasting Biological Activities. J Phys Chem B 2015; 119:15235-46. [DOI: 10.1021/acs.jpcb.5b09685] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Robert M. Hayden
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Gina K. Goldberg
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Bryan M. Ferguson
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Mason W. Schoeneck
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - M. Daben J. Libardo
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Sophie E. Mayeux
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Akritee Shrestha
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Kimberly A. Bogardus
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Janet Hammer
- Department
of Biomedical Sciences, Ohio University, Athens, Ohio 45701, United States
| | - Sergey Pryshchep
- Center
for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Herman K. Lehman
- Department
of Biology, Hamilton College, Clinton, New York 13323, United States
| | | | - Jack Blazyk
- Department
of Biomedical Sciences, Ohio University, Athens, Ohio 45701, United States
| | - Alfredo M. Angeles-Boza
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Riqiang Fu
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Myriam L. Cotten
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
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27
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Beringer PM, Bensman TJ, Ho H, Agnello M, Denovel N, Nguyen A, Wong-Beringer A, She R, Tran DQ, Moskowitz SM, Selsted ME. Rhesus θ-defensin-1 (RTD-1) exhibits in vitro and in vivo activity against cystic fibrosis strains of Pseudomonas aeruginosa. J Antimicrob Chemother 2015; 71:181-8. [PMID: 26433781 DOI: 10.1093/jac/dkv301] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 08/23/2015] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Chronic endobronchial infections with Pseudomonas aeruginosa contribute to bronchiectasis and progressive loss of lung function in patients with cystic fibrosis. This study aimed to evaluate the therapeutic potential of a novel macrocyclic peptide, rhesus θ-defensin-1 (RTD-1), by characterizing its in vitro antipseudomonal activity and in vivo efficacy in a murine model of chronic Pseudomonas lung infection. METHODS Antibacterial testing of RTD-1 was performed on 41 clinical isolates of P. aeruginosa obtained from cystic fibrosis patients. MIC, MBC, time-kill and post-antibiotic effects were evaluated following CLSI-recommended methodology, but using anion-depleted Mueller-Hinton broth. RTD-1 was nebulized daily for 7 days to cystic fibrosis transmembrane conductance regulator (CFTR) F508del-homozygous mice infected using the agar bead model of chronic P. aeruginosa lung infection. In vivo activity was evaluated by change in lung bacterial burden, airway leucocytes and body weight. RESULTS RTD-1 exhibited potent in vitro bactericidal activity against mucoid and non-mucoid strains of P. aeruginosa (MIC90 = 8 mg/L). Cross-resistance was not observed when tested against MDR and colistin-resistant isolates. Time-kill studies indicated very rapid, concentration-dependent bactericidal activity of RTD-1 with ≥3 log10 cfu/mL reductions at concentrations ≥4× MIC. No post-antibiotic effect was observed. In vivo, nebulized treatment with RTD-1 significantly decreased lung P. aeruginosa burden (mean difference of -1.30 log10 cfu; P = 0.0061), airway leucocytes (mean difference of -0.37 log10; P = 0.0012) and weight loss (mean difference of -12.62% at day 7; P < 0.05) when compared with controls. CONCLUSIONS This study suggests that RTD-1 is a promising potential therapeutic agent for cystic fibrosis airway disease.
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Affiliation(s)
- Paul M Beringer
- School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90033, USA
| | - Timothy J Bensman
- School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90033, USA
| | - Henry Ho
- School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90033, USA
| | - Melissa Agnello
- School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90033, USA
| | - Nicole Denovel
- School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90033, USA
| | - Albert Nguyen
- School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90033, USA
| | - Annie Wong-Beringer
- School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90033, USA
| | - Rosemary She
- Department of Pathology & Laboratory Medicine, Keck School of Medicine, University of Southern California, 2011 Zonal Avenue, Los Angeles, CA 90033, USA
| | - Dat Q Tran
- Department of Pathology & Laboratory Medicine, Keck School of Medicine, University of Southern California, 2011 Zonal Avenue, Los Angeles, CA 90033, USA
| | - Samuel M Moskowitz
- Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, 275 Cambridge Street, Boston, MA, USA
| | - Michael E Selsted
- Department of Pathology & Laboratory Medicine, Keck School of Medicine, University of Southern California, 2011 Zonal Avenue, Los Angeles, CA 90033, USA USC Norris Comprehensive Cancer Center, 1441 Eastlake Avenue, Los Angeles, CA, USA
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28
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Abstract
Defensins are a class of immune peptides with a broad range of activities against bacterial, fungal and viral pathogens. Besides exerting direct anti-microbial activity via dis-organization of bacterial membranes, defensins are also able to neutralize various unrelated bacterial toxins. Recently, we have demonstrated that in the case of human α- and β-defensins, this later ability is achieved through exploiting toxins' marginal thermodynamic stability, i.e. defensins act as molecular anti-chaperones unfolding toxin molecules and exposing their hydrophobic regions and thus promoting toxin precipitation and inactivation [Kudryashova et al. (2014) Immunity 41, 709-721]. Retrocyclins (RCs) are humanized synthetic θ-defensin peptides that possess unique cyclic structure, differentiating them from α- and β-defensins. Importantly, RCs are more potent against some bacterial and viral pathogens and more stable than their linear counterparts. However, the mechanism of bacterial toxin inactivation by RCs is not known. In the present study, we demonstrate that RCs facilitate unfolding of bacterial toxins. Using differential scanning fluorimetry (DSF), limited proteolysis and collisional quenching of internal tryptophan fluorescence, we show that hydrophobic regions of toxins normally buried in the molecule interior become more exposed to solvents and accessible to proteolytic cleavage in the presence of RCs. The RC-induced unfolding of toxins led to their precipitation and abrogated activity. Toxin inactivation by RCs was strongly diminished under reducing conditions, but preserved at physiological salt and serum concentrations. Therefore, despite significant structural diversity, α-, β- and θ-defensins employ similar mechanisms of toxin inactivation, which may be shared by anti-microbial peptides from other families.
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Johnson GP, Lloyd AT, O'Farrelly C, Meade KG, Fair S. Comparative genomic identification and expression profiling of a novel ?-defensin gene cluster in the equine reproductive tract. Reprod Fertil Dev 2015; 28:RD14345. [PMID: 25924226 DOI: 10.1071/rd14345] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 02/07/2015] [Indexed: 12/21/2022] Open
Abstract
?-defensins are small cationic proteins with potent immunoregulatory and antimicrobial activity. The number of genes encoding these peptides varies significantly between and within species but they have not been extensively characterised in the horse. Here, we describe a systematic search of the Equus caballus genome that identified a cluster of novel ?-defensin genes on Chromosome 22, which is homologous to a cluster on bovine Chromosome 13. Close genomic matches were found for orthologs of 13 of the bovine genes, which were named equine ?-defensins (eBD) 115, eBD116, eBD117, eBD119, eBD120, eBD122a, eBD123, eBD124, eBD125, eBD126, eBD127, eBD129 and eBD132. As expression of the homologous cluster in cattle was limited to the reproductive tract, tissue sections were obtained from the testis, caput, corpus and cauda epididymis and the vas deferens of three stallions and from the ovary, oviduct, uterine horn, uterus, cervix and vagina of three mares. Using a quantitative real-time polymerase chain reaction approach, each of the novel ?-defensin genes showed distinct region-specific patterns of expression. Preferential expression in the caput epididymis of these novel defensins in the stallion and in the oviduct in the mare suggests a possible role in immunoprotection of the equine reproductive tract or in fertility.
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Lipkin RB, Lazaridis T. Implicit Membrane Investigation of the Stability of Antimicrobial Peptide β-Barrels and Arcs. J Membr Biol 2014; 248:469-86. [PMID: 25430621 DOI: 10.1007/s00232-014-9759-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 11/18/2014] [Indexed: 12/31/2022]
Abstract
Previous simulations showed that the β-hairpin antimicrobial peptide (AMP) protegrin-1 can form stable octameric β-barrels and tetrameric arcs (half barrels) in both implicit and explicit membranes. Here, we extend this investigation to several AMPs of similar structure: tachyplesin, androctonin, polyphemusin, gomesin, and the retrocyclin θ-defensin. These peptides form short β-hairpins stabilized by 2-3 disulfide bonds. We also examine synthetic β-sheet peptides selected from a combinatorial library for their ability or inability to form pores in lipid membranes. When heptameric, octameric, and decameric β-barrels and tetrameric arcs of these peptides were embedded in pre-formed neutral or anionic lipid pores (i.e., pores in neutral or anionic membranes, respectively), a variety of behaviors and membrane binding energies were observed. Due to the cationic charge of the peptides, more favorable transfer energies and more stable binding were observed in anionic than neutral pores. The synthetic peptides bound very strongly and formed stable barrels and arcs in both neutral and anionic pores. The natural AMPs exhibited unfavorable or marginally favorable binding energy and kinetic stability in neutral pores, consistent with the lower hemolytic activity of some of them compared with protegrin-1. Binding to anionic pores was more favorable, but significant distortions of the barrel or arc structures were sometimes noted. These results are discussed in light of the available experimental data. The diversity of behaviors obtained makes it unlikely that the barrel and arc mechanisms are valid for the entire family of β-hairpin AMPs.
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Affiliation(s)
- Richard B Lipkin
- Department of Chemistry, City College of the City University of New York, 160 Convent Ave., New York, NY, 10031, USA
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31
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A hybrid cationic peptide composed of human β-defensin-1 and humanized θ-defensin sequences exhibits salt-resistant antimicrobial activity. Antimicrob Agents Chemother 2014; 59:217-25. [PMID: 25348533 DOI: 10.1128/aac.03901-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have designed a hybrid peptide by combining sequences of human β-defensin-1 (HBD-1) and θ-defensin, in an attempt to generate a molecule that combines the diversity in structure and biological activity of two different peptides to yield a promising therapeutic candidate. HBD-1 was chosen as it is a natural defensin of humans that is constitutively expressed, but its antibacterial activity is considerably impaired by elevated ionic strength. θ-Defensins are expressed in human bone marrow as a pseudogene and are homologous to rhesus monkey circular minidefensins. Retrocyclins are synthetic human θ-defensins. The cyclic nature of the θ-defensin peptides makes them salt resistant, nonhemolytic, and virtually noncytotoxic in vitro. However, a nonhuman circular molecule developed for clinical use would be less viable than a linear molecule. In this study, we have fused the C-terminal region of HBD-1 to the nonapeptide sequence of a synthetic retrocyclin. Cyclization was achieved by joining the terminal ends of the hybrid peptide by a disulfide bridge. The hybrid peptide with or without the disulfide bridge exhibited enhanced antimicrobial activity against both Gram-negative and Gram-positive bacteria as well as against fungi, including clinical bacterial isolates from eye infections. The peptide retained activity in the presence of NaCl and serum and was nonhemolytic in vitro. Thus, the hybrid peptide generated holds potential as a new class of antibiotics.
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32
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Abstract
There is a pressing need to develop new antiviral treatments; of the 60 drugs currently available, half are aimed at HIV-1 and the remainder target only a further six viruses. This demand has led to the emergence of possible peptide therapies, with 15 currently in clinical trials. Advancements in understanding the antiviral potential of naturally occurring host defence peptides highlights the potential of a whole new class of molecules to be considered as antiviral therapeutics. Cationic host defence peptides, such as defensins and cathelicidins, are important components of innate immunity with antimicrobial and immunomodulatory capabilities. In recent years they have also been shown to be natural, broad-spectrum antivirals against both enveloped and non-enveloped viruses, including HIV-1, influenza virus, respiratory syncytial virus and herpes simplex virus. Here we review the antiviral properties of several families of these host peptides and their potential to inform the design of novel therapeutics.
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Affiliation(s)
- Emily Gwyer Findlay
- MRC Centre for Inflammation Research, Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ Scotland, UK
| | - Silke M. Currie
- MRC Centre for Inflammation Research, Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ Scotland, UK
| | - Donald J. Davidson
- MRC Centre for Inflammation Research, Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ Scotland, UK
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33
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Northfield SE, Wang CK, Schroeder CI, Durek T, Kan MW, Swedberg JE, Craik DJ. Disulfide-rich macrocyclic peptides as templates in drug design. Eur J Med Chem 2014; 77:248-57. [DOI: 10.1016/j.ejmech.2014.03.011] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 02/25/2014] [Accepted: 03/05/2014] [Indexed: 01/04/2023]
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34
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Conibear AC, Bochen A, Rosengren KJ, Stupar P, Wang C, Kessler H, Craik DJ. The Cyclic Cystine Ladder of Theta-Defensins as a Stable, Bifunctional Scaffold: A Proof-of-Concept Study Using the Integrin-Binding RGD Motif. Chembiochem 2014; 15:451-9. [DOI: 10.1002/cbic.201300568] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Indexed: 11/06/2022]
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35
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Tai KP, Kamdar K, Yamaki J, Le VV, Tran D, Tran P, Selsted ME, Ouellette AJ, Wong-Beringer A. Microbicidal effects of α- and θ-defensins against antibiotic-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Innate Immun 2013; 21:17-29. [PMID: 24345876 DOI: 10.1177/1753425913514784] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Antibiotic-resistant bacterial pathogens threaten public health. Because many antibiotics target specific bacterial enzymes or reactions, corresponding genes may mutate under selection and lead to antibiotic resistance. Accordingly, antimicrobials that selectively target overall microbial cell integrity may offer alternative approaches to therapeutic design. Naturally occurring mammalian α- and θ-defensins are potent, non-toxic microbicides that may be useful for treating infections by antibiotic-resistant pathogens because certain defensin peptides disrupt bacterial, but not mammalian, cell membranes. To test this concept, clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA), including vancomycin heteroresistant strains, and ciprofloxacin-resistant Pseudomonas aeruginosa (Cip(R)-PA) were tested for sensitivity to α-defensins Crp-4, RMAD-4 and HNPs 1-3, and to RTD-1, macaque θ-defensin-1. In vitro, 3 μM Crp-4, RMAD-4 and RTD-1 reduced MRSA cell survival by 99%, regardless of vancomycin susceptibility. For PA clinical isolates that differ in fluoroquinolone resistance and virulence phenotype, peptide efficacy was independent of strain ciprofloxacin resistance, site of isolation or virulence factor expression. Thus, Crp-4, RMAD-4 and RTD-1 are effective in vitro antimicrobials against clinical isolates of MRSA and Cip(R)-PA, perhaps providing templates for development of α- and θ-defensin-based microbicides against antibiotic resistant or virulent infectious agents.
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Affiliation(s)
- Kenneth P Tai
- Department of Pathology and Laboratory Medicine, USC Norris Cancer Center, Keck School of Medicine, Los Angeles, CA, USA
| | - Karishma Kamdar
- Department of Pathology and Laboratory Medicine, USC Norris Cancer Center, Keck School of Medicine, Los Angeles, CA, USA
| | - Jason Yamaki
- Titus Family Department of Clinical Pharmacy and Pharmaceutical Economics and Policy, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Valerie V Le
- Department of Pathology and Laboratory Medicine, USC Norris Cancer Center, Keck School of Medicine, Los Angeles, CA, USA
| | - Dat Tran
- Department of Pathology and Laboratory Medicine, USC Norris Cancer Center, Keck School of Medicine, Los Angeles, CA, USA
| | - Patti Tran
- Department of Pathology and Laboratory Medicine, USC Norris Cancer Center, Keck School of Medicine, Los Angeles, CA, USA
| | - Michael E Selsted
- Department of Pathology and Laboratory Medicine, USC Norris Cancer Center, Keck School of Medicine, Los Angeles, CA, USA
| | - André J Ouellette
- Department of Pathology and Laboratory Medicine, USC Norris Cancer Center, Keck School of Medicine, Los Angeles, CA, USA
| | - Annie Wong-Beringer
- Titus Family Department of Clinical Pharmacy and Pharmaceutical Economics and Policy, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
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36
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Defensins: natural component of human innate immunity. Hum Immunol 2013; 74:1069-79. [PMID: 23756165 DOI: 10.1016/j.humimm.2013.05.008] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 04/23/2013] [Accepted: 05/29/2013] [Indexed: 12/19/2022]
Abstract
The widespread use of antibiotics has contributed to a huge increase in the number of resistant bacteria. New classes of drugs are therefore being developed of which defensins are a potential source. Defensins are a group of antimicrobial peptides found in different living organisms, involved in the first line of defense in their innate immune response against pathogens. This review summarizes the results of studies of this family of human antimicrobial peptides (AMPs). There is a special emphasis on describing the entire group and individual peptides, history of their discovery, their functions and expression sites. The results of the recent studies on the use of the biologically active peptides in human medicine are also presented. The pharmaceutical potential of human defensins cannot be ignored, especially considering their strong antimicrobial activity and properties such as low molecular weight, reduced immunogenicity, broad activity spectrum and resistance to proteolysis, but there are still many challenges and questions regarding the possibilities of their practical application.
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37
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Schaal JB, Tran D, Tran P, Ösapay G, Trinh K, Roberts KD, Brasky KM, Tongaonkar P, Ouellette AJ, Selsted ME. Rhesus macaque theta defensins suppress inflammatory cytokines and enhance survival in mouse models of bacteremic sepsis. PLoS One 2012; 7:e51337. [PMID: 23236475 PMCID: PMC3516535 DOI: 10.1371/journal.pone.0051337] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 11/07/2012] [Indexed: 02/08/2023] Open
Abstract
Theta-defensins (θ-defensins) are macrocyclic antimicrobial peptides expressed in leukocytes of Old World monkeys. The peptides are broad spectrum microbicides in vitro and numerous θ-defensin isoforms have been identified in granulocytes of rhesus macaques and Olive baboons. Several mammalian α- and β-defensins, genetically related to θ-defensins, have proinflammatory and immune-activating properties that bridge innate and acquired immunity. In the current study we analyzed the immunoregulatory properties of rhesus θ-defensins 1–5 (RTDs 1–5). RTD-1, the most abundant θ-defensin in macaques, reduced the levels of TNF, IL-1α, IL-1β, IL-6, and IL-8 secreted by blood leukocytes stimulated by several TLR agonists. RTDs 1–5 suppressed levels of soluble TNF released by bacteria- or LPS-stimulated blood leukocytes and THP-1 monocytes. Despite their highly conserved conformation and amino acid sequences, the anti-TNF activities of RTDs 1–5 varied by as much as 10-fold. Systemically administered RTD-1 was non-toxic for BALB/c mice, and escalating intravenous doses were well tolerated and non-immunogenic in adult chimpanzees. The peptide was highly stable in serum and plasma. Single dose administration of RTD-1 at 5 mg/kg significantly improved survival of BALB/c mice with E. coli peritonitis and cecal ligation-and-puncture induced polymicrobial sepsis. Peptide treatment reduced serum levels of several inflammatory cytokines/chemokines in bacteremic animals. Collectively, these results indicate that the anti-inflammatory properties of θ-defensins in vitro and in vivo are mediated by the suppression of numerous proinflammatory cytokines and blockade of TNF release may be a primary effect.
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Affiliation(s)
- Justin B. Schaal
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Dat Tran
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Patti Tran
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - George Ösapay
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, California, United States of America
| | - Katie Trinh
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Kevin D. Roberts
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Kathleen M. Brasky
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Prasad Tongaonkar
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - André J. Ouellette
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- Kenneth Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, United States of America
| | - Michael E. Selsted
- Department of Pathology and Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- Kenneth Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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38
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A non-cyclic baboon θ-defensin derivative exhibiting antimicrobial activity against the phytopathogen Verticillium dahliae. Appl Microbiol Biotechnol 2012; 97:2043-52. [PMID: 22903319 DOI: 10.1007/s00253-012-4309-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Revised: 07/13/2012] [Accepted: 07/14/2012] [Indexed: 01/19/2023]
Abstract
θ-Defensins are the only natural cyclic proteins found in primates. They have strong antimicrobial activity related to their trisulfide ladders and macrocyclic conformation. A non-cyclic baboon θ-defensin (BTD) was synthesized by substituting valine with phenylalanine at position 17, at the C-terminal end of the BTD; this was termed "BTD-S." The antimicrobial activities of this synthetic peptide were investigated against Escherichia coli and two cotton phytopathogens: Verticillium dahliae and Fusarium oxysporum. The minimum inhibitory concentration (MIC) of BTD-S for E. coli was 10 μg/mL and for V. dahliae was 5 μg/mL, significantly lower than that for F. oxysporum (40.0 μg/mL). A time course analysis of fungal cultures indicated that the growth of V. dahliae was completely inhibited after 96 h of BTD-S treatment. Furthermore, hemolysis assays revealed that BTD-S was not toxic to mammalian cells as it could not induce lysis of sheep red blood cells even at ten times the MIC (50 μg/mL). Scanning electron microscopy and double-stained (calcofluor white and propidium iodide binding) fluorescence microscopy showed that exposure of spores of V. dahliae to BTD-S either disabled normal germination or disintegrated the spores. The size of cells exposed to BTD-S was significantly reduced compared with controls, and their number increased in a dose-dependent curve when measured by flow cytometry. These findings suggest that BTD-S has great potential to inhibit the growth of V. dahliae and can be utilized as an effective remedy to control economic losses caused by Verticillium wilt in the development of wilt-resistant cotton.
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39
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Lehrer RI, Cole AM, Selsted ME. θ-Defensins: cyclic peptides with endless potential. J Biol Chem 2012; 287:27014-9. [PMID: 22700960 DOI: 10.1074/jbc.r112.346098] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
θ-Defensins, the only cyclic peptides of animal origin, have been isolated from the leukocytes of rhesus macaques and baboons. Their biogenesis is unusual because each peptide is an 18-residue chimera formed by the head-to-tail splicing of nonapeptides derived from two separate precursors. θ-Defensins have multiple arginines and a ladder-like tridisulfide array spanning their two antiparallel β-strands. Human θ-defensin genes contain a premature stop codon that prevents effective translation of the needed precursors; consequently, these peptides are not present in human leukocytes. Synthetic θ-defensins with sequences that correspond to those encoded within the human pseudogenes are called retrocyclins. Retrocyclin-1 inhibits the cellular entry of HIV-1, HSV, and influenza A virus. The rhesus θ-defensin RTD-1 protects mice from an experimental severe acute respiratory syndrome coronavirus infection, and retrocyclin-1 protects mice from infection by Bacillus anthracis spores. The small size, unique structure, and multiple host defense activities of θ-defensins make them intriguing potential therapeutic agents.
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Affiliation(s)
- Robert I Lehrer
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1688, USA.
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40
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Eade CR, Wood MP, Cole AM. Mechanisms and modifications of naturally occurring host defense peptides for anti-HIV microbicide development. Curr HIV Res 2012; 10:61-72. [PMID: 22264047 DOI: 10.2174/157016212799304580] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 09/30/2011] [Accepted: 10/27/2011] [Indexed: 11/22/2022]
Abstract
Despite advances in the treatment of HIV infection, heterosexual transmission of HIV remains high, and vaccines to prevent HIV acquisition have been unfruitful. Vaginal microbicides, on the other hand, have demonstrated considerable potential for HIV prevention, and a variety of compounds have been screened for their activity and safety as anti-HIV microbicides. Among these are the naturally occurring host defense peptides, small peptides from diverse lineages with intrinsic antiviral activity. Naturally occurring host defense peptides with anti-HIV activity are promising candidates for vaginal microbicide development. Their structural variance and accompanying mechanistic diversity provide a wide range of inhibitors whose antiviral activity can be exerted at nearly every stage of the HIV lifecycle. Additionally, peptide modification has been explored as a method for improving the anti-HIV activity of host defense peptides. Structure- and sequence-based alterations have achieved varying success in improving the potency and specificity of anti-HIV peptides. Overall, peptides have been discovered or engineered to inhibit HIV with therapeutic indices of > 1000, encouraging their advancement toward clinical trials. Here we review the naturally occurring anti-HIV host defense peptides, demonstrating their breadth of mechanistic diversity, and exploring approaches to enhance and optimize their activity in order to expedite their development as safe and effective anti-HIV vaginal microbicides.
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Affiliation(s)
- Colleen R Eade
- Department of Molecular Biology and Microbiology, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, FL 32816, USA.
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41
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Abstract
Defensins are small, multifunctional cationic peptides. They typically contain six conserved cysteines whose three intramolecular disulfides stabilize a largely β-sheet structure. This review of human α-defensins begins by describing their evolution, including their likely relationship to the Big Defensins of invertebrates, and their kinship to the β-defensin peptides of many if not all vertebrates, and the θ-defensins found in certain non-human primates. We provide a short history of the search for leukocyte-derived microbicidal molecules, emphasizing the roles played by luck (good), preconceived notions (mostly bad), and proper timing (essential). The antimicrobial, antiviral, antitoxic, and binding properties of human α-defensins are summarized. The structural features of α-defensins are described extensively and their functional contributions are assessed. The properties of HD6, an enigmatic Paneth cell α-defensin, are contrasted with those of the four myeloid α-defensins (HNP1-4) and of HD5, the other α-defensin of human Paneth cells. The review ends with a decalogue that may assist researchers or students interested in α-defensins and related aspects of neutrophil function.
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Affiliation(s)
- Robert I Lehrer
- Department of Medicine and Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1688, USA.
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42
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Rapireddy S, Nhon L, Meehan RE, Franks J, Stolz DB, Tran D, Selsted ME, Ly DH. RTD-1mimic containing γPNA scaffold exhibits broad-spectrum antibacterial activities. J Am Chem Soc 2012; 134:4041-4. [PMID: 22332599 PMCID: PMC4848027 DOI: 10.1021/ja211867j] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Macrocyclic peptides with multiple disulfide cross-linkages, such as those produced by plants and those found in nonhuman primates, as components of the innate immunity, hold great promise for molecular therapy because of their broad biological activities and high chemical, thermal, and enzymatic stability. However, for some, because of their intricate spatial arrangement and elaborate interstrand cross-linkages, they are difficult to prepare de novo in large quantities and high purity, due to the nonselective nature of disulfide-bond formation. We show that the disulfide bridges of RTD-1, a member of the θ-defensin subfamily, could be replaced with noncovalent Watson-Crick hydrogen bonds without significantly affecting its biological activities. The work provides a general strategy for engineering conformationally rigid, cyclic peptides without the need for disulfide-bond reinforcement.
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Affiliation(s)
- Srinivas Rapireddy
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| | - Linda Nhon
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| | - Robert E. Meehan
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| | - Jonathan Franks
- Department of Cell Biology & Physiology, University of Pittsburgh School of Medicine, S362 BST, 3500 Terrace Street, Pittsburgh, PA 15261
| | - Donna Beer Stolz
- Department of Cell Biology & Physiology, University of Pittsburgh School of Medicine, S362 BST, 3500 Terrace Street, Pittsburgh, PA 15261
| | - Dat Tran
- Department of Pathology & Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
| | - Michael E. Selsted
- Department of Pathology & Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
| | - Danith H. Ly
- Department of Chemistry and Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
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Aboye TL, Li Y, Majumder S, Hao J, Shekhtman A, Camarero JA. Efficient one-pot cyclization/folding of Rhesus θ-defensin-1 (RTD-1). Bioorg Med Chem Lett 2012; 22:2823-6. [PMID: 22425570 DOI: 10.1016/j.bmcl.2012.02.080] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 02/18/2012] [Accepted: 02/23/2012] [Indexed: 12/30/2022]
Abstract
We report an efficient approach for the chemical synthesis of Rhesus θ-defensin-1 (RTD-1) using Fmoc-based solid-phase peptide synthesis in combination with an intramolecular version of native chemical ligation. The corresponding linear thioester precursor was cyclized and folded in a one-pot reaction using reduced glutathione. The reaction was extremely efficiently yielding natively folded RTD-1 with minimal or no purification at all. This approach is fully compatible with the high throughput production of chemical libraries using this peptide scaffold.
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Affiliation(s)
- Teshome L Aboye
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90033, USA
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Gould A, Li Y, Majumder S, Garcia AE, Carlsson P, Shekhtman A, Camarero JA. Recombinant production of rhesus θ-defensin-1 (RTD-1) using a bacterial expression system. MOLECULAR BIOSYSTEMS 2012; 8:1359-65. [PMID: 22327102 DOI: 10.1039/c2mb05451e] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Defensins are antimicrobial peptides that are important in the innate immune defense of mammals. In contrast to mammalian α- and β-defensins, rhesus θ-defensin-1 (RTD-1) comprises only 18 amino acids stabilized by three disulfide bonds and an unusual backbone cyclic topology. In this work we report for the first time the recombinant expression of the fully folded θ-defensin RTD-1 using a bacterial expression system. This was accomplished using an intramolecular native chemical ligation in combination with a modified protein-splicing unit. RTD-1 was produced either in vitro or in vivo. In-cell production of RTD-1 was estimated to reach an intracellular concentration of ~4 μM. Recombinant RTD-1 was shown to be correctly folded as characterized by heteronuclear-NMR and by its ability to specifically inhibit lethal factor protease. The recombinant production of folded θ-defensins opens the possibility to produce peptide libraries based on this peptide scaffold that could be used to develop in-cell screening and directed evolution technologies.
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Affiliation(s)
- Andrew Gould
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90033, USA
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Pasupuleti M, Schmidtchen A, Malmsten M. Antimicrobial peptides: key components of the innate immune system. Crit Rev Biotechnol 2011; 32:143-71. [PMID: 22074402 DOI: 10.3109/07388551.2011.594423] [Citation(s) in RCA: 500] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Life-threatening infectious diseases are on their way to cause a worldwide crisis, as treating them effectively is becoming increasingly difficult due to the emergence of antibiotic resistant strains. Antimicrobial peptides (AMPs) form an ancient type of innate immunity found universally in all living organisms, providing a principal first-line of defense against the invading pathogens. The unique diverse function and architecture of AMPs has attracted considerable attention by scientists, both in terms of understanding the basic biology of the innate immune system, and as a tool in the design of molecular templates for new anti-infective drugs. AMPs are gene-encoded short (<100 amino acids), amphipathic molecules with hydrophobic and cationic amino acids arranged spatially, which exhibit broad spectrum antimicrobial activity. AMPs have been the subject of natural evolution, as have the microbes, for hundreds of millions of years. Despite this long history of co-evolution, AMPs have not lost their ability to kill or inhibit the microbes totally, nor have the microbes learnt to avoid the lethal punch of AMPs. AMPs therefore have potential to provide an important breakthrough and form the basis for a new class of antibiotics. In this review, we would like to give an overview of cationic antimicrobial peptides, origin, structure, functions, and mode of action of AMPs, which are highly expressed and found in humans, as well as a brief discussion about widely abundant, well characterized AMPs in mammals, in addition to pharmaceutical aspects and the additional functions of AMPs.
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Affiliation(s)
- Mukesh Pasupuleti
- Department of Microbiology and Immunology, Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, Canada.
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Abstract
This paper reports the use of natural amino acids, the tripeptide β-strand mimic Hao, and the β-turn mimic δ-linked ornithine to generate water-soluble 54-, 78-, and 102-membered-ring macrolactams. These giant macrocycles were efficiently prepared by synthesis of the corresponding protected linear peptides, followed by solution-phase cyclization and deprotection. The protected linear peptide precursors were synthesized on 2-chlorotrityl chloride resin by conventional Fmoc-based solid-phase peptide synthesis. Macrocyclization was typically performed using HCTU and N,N-diisopropylethylamine in DMF at ca. 0.5 mM concentration. The macrocycles were isolated in 13-45% overall yield after HPLC purification and lyophilization. 1D, 2D TOCSY, and 2D ROESY (1)H NMR studies of the 54- and 78-membered-ring macrolactams establish that these compounds fold to form β-sheet structures in aqueous solutions.
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Affiliation(s)
- Pin-Nan Cheng
- Department of Chemistry University of California, Irvine Irvine, CA 92697-2025
| | - James S. Nowick
- Department of Chemistry University of California, Irvine Irvine, CA 92697-2025
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Chrudimská T, Slaninová J, Rudenko N, Růžek D, Grubhoffer L. Functional characterization of two defensin isoforms of the hard tick Ixodes ricinus. Parasit Vectors 2011; 4:63. [PMID: 21504572 PMCID: PMC3102633 DOI: 10.1186/1756-3305-4-63] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 04/19/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The immune system of ticks is stimulated to produce many pharmacologically active molecules during feeding and especially during pathogen invasion. The family of cationic peptides - defensins - represents a specific group of antimicrobial compounds with six conserved cysteine residues in a molecule. RESULTS Two isoforms of the defensin gene (def1 and def2) were identified in the European tick Ixodes ricinus. Expression of both genes was induced in different tick organs by a blood feeding or pathogen injection. We have tested the ability of synthetic peptides def1 and def2 to inhibit the growth or directly kill several pathogens. The antimicrobial activities (expressed as minimal inhibition concentration and minimal bactericidal concentration values) against Gram positive bacteria were confirmed, while Gram negative bacteria, yeast, Tick Borne Encephalitis and West Nile Viruses were shown to be insensitive. In addition to antimicrobial activities, the hemolysis effect of def1 and def2 on human erythrocytes was also established. CONCLUSIONS Although there is nothing known about the realistic concentration of defensins in I. ricinus tick body, these results suggest that defensins play an important role in defence against different pathogens. Moreover this is a first report of a one amino acid substitution in a defensins molecule and its impact on antimicrobial activity.
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Affiliation(s)
- Tereza Chrudimská
- University of South Bohemia, Faculty of Science, České Buděovice, Czech Republic.
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Tongaonkar P, Tran P, Roberts K, Schaal J, Osapay G, Tran D, Ouellette AJ, Selsted ME. Rhesus macaque θ-defensin isoforms: expression, antimicrobial activities, and demonstration of a prominent role in neutrophil granule microbicidal activities. J Leukoc Biol 2010; 89:283-90. [PMID: 21084627 DOI: 10.1189/jlb.0910535] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Mammalian defensins are cationic, antimicrobial peptides that play a central role in innate immunity. The peptides are composed of three structural subfamilies: α-, β-, and θ-defensins. θ-defensins are macrocyclic octadecapeptides expressed only in Old World monkeys and orangutans and are produced by the pair-wise, head-to-tail splicing of nonapeptides derived from their respective precursors. The existence of three active θ-defensin genes predicts that six different RTDs (1-6) are produced in this species. In this study, we isolated and quantified RTDs 1-6 from the neutrophils of 10 rhesus monkeys. RTD-1 was the most abundant θ-defensin, constituting ~50% of the RTD content; total RTD content varied by as much as threefold between animals. All peptides tested were microbicidal at ∼1 μM concentrations. The contribution of θ-defensins to macaque neutrophil antimicrobial activity was assessed by analyzing the microbicidal properties of neutrophil granule extracts after neutralizing θ-defensin content with a specific antibody. θ-defensin neutralization markedly reduced microbicidal activities of the corresponding extracts. Macaque neutrophil granule extracts had significantly greater microbicidal activity than those of human neutrophils, which lack θ-defensins. Supplementation of human granule extracts with RTD-1 markedly increased the microbicidal activity of these preparations, further demonstrating a prominent microbicidal role for θ-defensins.
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Affiliation(s)
- Prasad Tongaonkar
- Department of Pathology & Laboratory Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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Das S, Nikolaidis N, Goto H, McCallister C, Li J, Hirano M, Cooper MD. Comparative genomics and evolution of the alpha-defensin multigene family in primates. Mol Biol Evol 2010; 27:2333-43. [PMID: 20457584 DOI: 10.1093/molbev/msq118] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Defensin genes encode small cationic antimicrobial peptides that form an important part of the innate immune system. They are divided into three families, alpha (α), beta (β), and theta (), according to arrangement of the disulfide bonding pattern between cysteine residues. Considering the functional importance of defensins, investigators have studied the evolution and the genomic organization of defensin genes. However, these studies have been restricted mainly to β-defensins. To understand the evolutionary dynamics of α-defensin genes among primates, we identified the α-defensin repertoires in human, chimpanzee, orangutan, macaque, and marmoset. The α-defensin genes in primates can be classified into three phylogenetic classes (class I, II, and III). The presence of all three classes in the marmoset indicates that their divergence occurred before the separation of New World and Old World monkeys. Comparative analysis of the α-defensin genomic clusters suggests that the makeup of the α-defensin gene repertoires between primates is quite different, as their genes have undergone dramatic birth-and-death evolution. Analysis of the encoded peptides of the α-defensin genes indicates that despite the overall high level of sequence divergence, certain amino acid residues or motifs are conserved within and between the three phylogenetic classes. The evolution of α-defensins in primates, therefore, appears to be governed by two opposing evolutionary forces. One force stabilizes specific amino acid residues and motifs to preserve the functional and structural integrity of the molecules and the other diversifies the sequences generating molecules with a wide range of activities against a large number of pathogens.
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Affiliation(s)
- Sabyasachi Das
- Department of Pathology and Laboratory Medicine, Emory Vaccine Center, School of Medicine, Emory University, USA.
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Comegna D, Benincasa M, Gennaro R, Izzo I, De Riccardis F. Design, synthesis and antimicrobial properties of non-hemolytic cationic alpha-cyclopeptoids. Bioorg Med Chem 2010; 18:2010-8. [PMID: 20153656 DOI: 10.1016/j.bmc.2010.01.026] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 01/08/2010] [Accepted: 01/09/2010] [Indexed: 11/19/2022]
Abstract
The synthesis and screening of neutral and cationic, linear and cyclic peptoids (N-alkylglycine peptidomimetics) is described. Structure-activity relationship studies show that the in vitro activities of the tested peptoids depend on both cyclization and decoration with cationic groups. The most powerful N-lysine cyclopeptoid derivatives showed good antifungal activity against Candida albicans (ATCC90029 and L21) and Candida famata (SA550, Amph B-resistant) and low hemolytic activity. The effects of the cyclic peptoids on membrane permeabilization were evaluated by the propidium iodide exclusion assay.
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Affiliation(s)
- Daniela Comegna
- Deparment of Chemistry, University of Salerno, Via Ponte Don Melillo, 84084 Fisciano (SA), Italy
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