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van der Walt M, Möller DS, van Wyk RJ, Ferguson PM, Hind CK, Clifford M, Do Carmo Silva P, Sutton JM, Mason AJ, Bester MJ, Gaspar ARM. QSAR Reveals Decreased Lipophilicity of Polar Residues Determines the Selectivity of Antimicrobial Peptide Activity. ACS OMEGA 2024; 9:26030-26049. [PMID: 38911757 PMCID: PMC11191095 DOI: 10.1021/acsomega.4c01277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/15/2024] [Accepted: 05/20/2024] [Indexed: 06/25/2024]
Abstract
Antimicrobial resistance has increased rapidly, causing daunting morbidity and mortality rates worldwide. Antimicrobial peptides (AMPs) have emerged as promising alternatives to traditional antibiotics due to their broad range of targets and low tendency to elicit resistance. However, potent antimicrobial activity is often accompanied by excessive cytotoxicity toward host cells, leading to a halt in AMP therapeutic development. Here, we present multivariate analyses that correlate 28 peptide properties to the activity and toxicity of 46 diverse African-derived AMPs and identify the negative lipophilicity of polar residues as an essential physiochemical property for selective antimicrobial activity. Twenty-seven active AMPs are identified, of which the majority are of scorpion or frog origin. Of these, thirteen are novel with no previously reported activities. Principal component analysis and quantitative structure-activity relationships (QSAR) reveal that overall hydrophobicity, lipophilicity, and residue side chain surface area affect the antimicrobial and cytotoxic activity of an AMP. This has been well documented previously, but the present QSAR analysis additionally reveals that a decrease in the lipophilicity, contributed by those amino acids classified as polar, confers selectivity for a peptide to pathogen over mammalian cells. Furthermore, an increase in overall peptide charge aids selectivity toward Gram-negative bacteria and fungi, while selectivity toward Gram-positive bacteria is obtained through an increased number of small lipophilic residues. Finally, a conservative increase in peptide size in terms of sequence length and molecular weight also contributes to improved activity without affecting toxicity. Our findings suggest a novel approach for the rational design or modification of existing AMPs to increase pathogen selectivity and enhance therapeutic potential.
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Affiliation(s)
- Mandelie van der Walt
- Department
of Biochemistry, Genetics and Microbiology, Faculty of Natural and
Agricultural Sciences, University of Pretoria, Pretoria 0002, South Africa
| | - Dalton S. Möller
- Department
of Biochemistry, Genetics and Microbiology, Faculty of Natural and
Agricultural Sciences, University of Pretoria, Pretoria 0002, South Africa
| | - Rosalind J. van Wyk
- Department
of Biochemistry, Genetics and Microbiology, Faculty of Natural and
Agricultural Sciences, University of Pretoria, Pretoria 0002, South Africa
| | - Philip M. Ferguson
- Institute
of Pharmaceutical Science, School of Cancer & Pharmaceutical Science, King’s College London, Franklin-Wilkins Building, 150 Stamford
Street, London SE1 9NH, United Kingdom
| | - Charlotte K. Hind
- Antimicrobial
Discovery Development and Diagnostics, Vaccine Evaluation and Development
Centre, UK Health Security Agency, Salisbury SP4 0JG, United Kingdom
| | - Melanie Clifford
- Antimicrobial
Discovery Development and Diagnostics, Vaccine Evaluation and Development
Centre, UK Health Security Agency, Salisbury SP4 0JG, United Kingdom
| | - Phoebe Do Carmo Silva
- Antimicrobial
Discovery Development and Diagnostics, Vaccine Evaluation and Development
Centre, UK Health Security Agency, Salisbury SP4 0JG, United Kingdom
| | - J. Mark Sutton
- Antimicrobial
Discovery Development and Diagnostics, Vaccine Evaluation and Development
Centre, UK Health Security Agency, Salisbury SP4 0JG, United Kingdom
| | - A. James Mason
- Institute
of Pharmaceutical Science, School of Cancer & Pharmaceutical Science, King’s College London, Franklin-Wilkins Building, 150 Stamford
Street, London SE1 9NH, United Kingdom
| | - Megan J. Bester
- Department
of Anatomy, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa
| | - Anabella R. M. Gaspar
- Department
of Biochemistry, Genetics and Microbiology, Faculty of Natural and
Agricultural Sciences, University of Pretoria, Pretoria 0002, South Africa
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2
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Chiramba C, Möller DS, Lorenz CD, Chirombo RR, Mason AJ, Bester MJ, Gaspar ARM. Tryptophan End-Tagging Confers Antifungal Activity on a Tick-Derived Peptide by Triggering Reactive Oxygen Species Production. ACS OMEGA 2024; 9:15556-15572. [PMID: 38585074 PMCID: PMC10993377 DOI: 10.1021/acsomega.4c00478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/26/2024] [Accepted: 03/07/2024] [Indexed: 04/09/2024]
Abstract
WHO has identified several Candida species including Candida albicans as critical priority fungal pathogens due to greater infection prevalence and formation of recalcitrant biofilms. Novel antifungal agents are urgently needed, and antimicrobial peptides (AMPs) are being considered as potential alternatives, but inactivity in physiological salt environments, serum, and plasma often limits further therapeutic development. Tryptophan end-tagging is a strategy to overcome these limitations and is thought to selectively enhance membrane permeabilization in both fungal and bacterial plasma membranes. Here, we show that C-terminal tryptophan end-tagging of the tick-derived peptide Os-C transforms an inactive peptide into Os-C(W5), an antifungal peptide capable of preventing the formation of C. albicans biofilms. Mechanistic insight is provided by circular dichroism spectroscopy and molecular dynamics simulations, which demonstrate that tryptophan end-tagging alters the secondary structure of Os-C, while the latter reveals that end-tagging reduces interactions with, and insertion into, a model C. albicans membrane but promotes peptide aggregation on its surface. Interestingly, this leads to the induction of reactive oxygen species production rather than membrane permeabilization, and consequently, oxidative stress leads to cell wall damage. Os-C(W5) does not induce the hemolysis of human erythrocytes. Reduced cell adhesion and viability contribute to decreased biofilm extracellular matrix formation which, although reduced, is retained in the serum-containing medium. In this study, tryptophan end-tagging was identified as a promising strategy for enhancing the antifungal activity, including the biofilm inhibitory activity of Os-C against C. albicans in physiological salt environments.
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Affiliation(s)
- Court
K. Chiramba
- Department
of Biochemistry, Genetics and Microbiology, Faculty of Natural and
Agricultural Sciences, University of Pretoria, Pretoria 0002, South Africa
| | - Dalton S. Möller
- Department
of Biochemistry, Genetics and Microbiology, Faculty of Natural and
Agricultural Sciences, University of Pretoria, Pretoria 0002, South Africa
| | | | - Rumbidzai R. Chirombo
- Department
of Anatomy, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa
| | - A. James Mason
- Institute
of Pharmaceutical Science, School of Cancer & Pharmaceutical Science, King’s College London, London SE1 9NH, U.K.
| | - Megan J. Bester
- Department
of Anatomy, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa
| | - Anabella R. M. Gaspar
- Department
of Biochemistry, Genetics and Microbiology, Faculty of Natural and
Agricultural Sciences, University of Pretoria, Pretoria 0002, South Africa
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Hilpert K, Munshi T, López-Pérez PM, Sequeira-Garcia J, Bull TJ. Redefining Peptide 14D: Substitutional Analysis for Accelerated TB Diagnosis and Enhanced Activity against Mycobacterium tuberculosis. Microorganisms 2024; 12:177. [PMID: 38258003 PMCID: PMC10819809 DOI: 10.3390/microorganisms12010177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/08/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024] Open
Abstract
Tuberculosis (TB) caused by Mycobacterium tuberculosis remains a predominant cause of mortality, especially in low- and middle-income nations. Recently, antimicrobial peptides have been discovered that at low concentrations could stimulate the growth of M. tuberculosis (hormetic response). In this study, such a peptide was used to investigate the effects on the time to positivity (TTP). A systematic substitution analysis of peptide 14D was synthesized using Spot synthesis technology, resulting in 171 novel peptides. Our findings revealed a spectrum of interactions, with some peptides accelerating M. tuberculosis growth, potentially aiding in faster diagnostics, while others exhibited inhibitory effects. Notably, peptide NH2-wkivfiwrr-CONH2 significantly reduced the TTP by 25 h compared to the wild-type peptide 14D, highlighting its potential in improving TB diagnostics by culture. Several peptides demonstrated potent antimycobacterial activity, with a minimum inhibitory concentration (MIC) of 20 µg/mL against H37Rv and a multidrug-resistant M. tuberculosis strain. Additionally, for two peptides, a strongly diminished formation of cord-like structures was observed, which is indicative of reduced virulence and transmission potential. This study underscores the multifaceted roles of antimicrobial peptides in TB management, from enhancing diagnostic efficiency to offering therapeutic avenues against M. tuberculosis.
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Affiliation(s)
- Kai Hilpert
- Institute of Infection and Immunity, St George’s, University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Tulika Munshi
- Institute of Infection and Immunity, St George’s, University of London, Cranmer Terrace, London SW17 0RE, UK
| | | | | | - Tim J. Bull
- Institute of Infection and Immunity, St George’s, University of London, Cranmer Terrace, London SW17 0RE, UK
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Ul Haq I, Maryam S, Shyntum DY, Khan TA, Li F. Exploring the frontiers of therapeutic breadth of antifungal peptides: A new avenue in antifungal drugs. J Ind Microbiol Biotechnol 2024; 51:kuae018. [PMID: 38710584 PMCID: PMC11119867 DOI: 10.1093/jimb/kuae018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 05/03/2024] [Indexed: 05/08/2024]
Abstract
The growing prevalence of fungal infections alongside rising resistance to antifungal drugs poses a significant challenge to public health safety. At the close of the 2000s, major pharmaceutical firms began to scale back on antimicrobial research due to repeated setbacks and diminished economic gains, leaving only smaller companies and research labs to pursue new antifungal solutions. Among various natural sources explored for novel antifungal compounds, antifungal peptides (AFPs) emerge as particularly promising. Despite their potential, AFPs receive less focus than their antibacterial counterparts. These peptides have been sourced extensively from nature, including plants, animals, insects, and especially bacteria and fungi. Furthermore, with advancements in recombinant biotechnology and computational biology, AFPs can also be synthesized in lab settings, facilitating peptide production. AFPs are noted for their wide-ranging efficacy, in vitro and in vivo safety, and ability to combat biofilms. They are distinguished by their high specificity, minimal toxicity to cells, and reduced likelihood of resistance development. This review aims to comprehensively cover AFPs, including their sources-both natural and synthetic-their antifungal and biofilm-fighting capabilities in laboratory and real-world settings, their action mechanisms, and the current status of AFP research. ONE-SENTENCE SUMMARY This comprehensive review of AFPs will be helpful for further research in antifungal research.
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Affiliation(s)
- Ihtisham Ul Haq
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, M. Strzody 9, 44-100 Gliwice, Poland
- Joint Doctoral School, Silesian University of Technology, Akademicka 2A, 44-100 Gliwice, Poland
- Programa de Pós-graduação em Inovação Tecnológica, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil
| | - Sajida Maryam
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, M. Strzody 9, 44-100 Gliwice, Poland
- Joint Doctoral School, Silesian University of Technology, Akademicka 2A, 44-100 Gliwice, Poland
| | - Divine Y Shyntum
- Biotechnology Centre, Silesian University of Technology, B. Krzywoustego 8, 44-100 Gliwice, Poland
| | - Taj A Khan
- Division of Infectious Diseases & Global Medicine, Department of Medicine, University of Florida, Gainesville, FL, USA
- Institute of Pathology and Diagnostic Medicine, Khyber Medical University, Peshawar, Pakistan
| | - Fan Li
- School of Life Sciences, Peking University, Beijing 100871, People's Republic of China
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Wu J, Zhou X, Chen Q, Chen Z, Zhang J, Yang L, Sun Y, Wang G, Dai J, Feng T. Defensins as a promising class of tick antimicrobial peptides: a scoping review. Infect Dis Poverty 2022; 11:71. [PMID: 35725522 PMCID: PMC9208123 DOI: 10.1186/s40249-022-00996-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 06/06/2022] [Indexed: 11/11/2022] Open
Abstract
Background Ticks are hematophagous parasites that transmit an extensive range of pathogens to their vertebrate hosts. Ticks can destroy invading microorganisms or alleviate infection via their rudimentary but orchestrated innate immune system. Antimicrobial peptides (AMPs) are important components of tick innate immunity. Among these humoral effector molecules, defensins are well-studied and widely identified in various species of Ixodidae (hard ticks) and Argasidae (soft ticks). This review was aimed at presenting the characterization of tick defensins from structure-based taxonomic status to antimicrobial function. Main text All published papers written in English from 2001 to May 2022 were searched through PubMed and Web of Science databases with the combination of relevant terms on tick defensins. Reports on identification and characterization of tick defensins were included. Of the 329 entries retrieved, 57 articles were finally eligible for our scoping review. Tick defensins mainly belong to the antibacterial ancient invertebrate-type defensins of the cis-defensins superfamily. They are generally small, cationic, and amphipathic, with six cysteine residues forming three intra-molecular disulfide bonds. Tick defensins primarily target membranes of a variety of pathogens, including Gram-positive and Gram-negative bacteria, fungi, viruses, and protozoa. Since tick defensins have a high degree of variability, we summarize their common biological properties and enumerate representative peptides. Along with the various and potent antimicrobial activities, the role of tick defensins in determining vector competence is discussed. Conclusions Due to their broad-spectrum antimicrobial activities, tick defensins are considered novel candidates or targets for controlling infectious diseases. Graphical Abstract ![]()
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Affiliation(s)
- Jiahui Wu
- Institute of Biology and Medical Sciences, Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Xia Zhou
- School of Biology and Basic Medical Science, Suzhou Medical College of Soochow University, Suzhou, China
| | - Qiaoqiao Chen
- Institute of Biology and Medical Sciences, Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Zhiqiang Chen
- Department of Nuclear Medicine, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Jinyu Zhang
- Institute of Biology and Medical Sciences, Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Lele Yang
- Institute of Biology and Medical Sciences, Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Yuxuan Sun
- Institute of Biology and Medical Sciences, Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Guohui Wang
- School of Life Science and Technology, Weifang Medical University, Weifang, China.
| | - Jianfeng Dai
- Institute of Biology and Medical Sciences, Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China.
| | - Tingting Feng
- Institute of Biology and Medical Sciences, Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China.
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