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Eng SJ, Nonnecke EB, de Lorimier AJ, Ali MR, Tsolis RM, Bevins CL, Ashwood P. FOXO inhibition rescues α-defensin expression in human intestinal organoids. Proc Natl Acad Sci U S A 2023; 120:e2312453120. [PMID: 37956278 PMCID: PMC10666032 DOI: 10.1073/pnas.2312453120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 10/05/2023] [Indexed: 11/15/2023] Open
Abstract
To mediate critical host-microbe interactions in the human small intestine, Paneth cells constitutively produce abundant levels of α-defensins and other antimicrobials. We report that the expression profile of these antimicrobials is dramatically askew in human small intestinal organoids (enteroids) as compared to that in paired tissue from which they are derived, with a reduction of α-defensins to nearly undetectable levels. Murine enteroids, however, recapitulate the expression profile of Paneth cell α-defensins seen in tissue. WNT/TCF signaling has been found to be instrumental in the regulation of α-defensins, yet in human enteroids exogenous stimulation of WNT signaling appears insufficient to rescue α-defensin expression. By stark contrast, forkhead box O (FOXO) inhibitor AS1842856 induced the expression of α-defensin mRNA in enteroids by >100,000-fold, restoring DEFA5 and DEFA6 to levels comparable to those found in primary human tissue. These results newly identify FOXO signaling as a pathway of biological and potentially therapeutic relevance for the regulation of human Paneth cell α-defensins in health and disease.
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Affiliation(s)
- Serena J. Eng
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA95616
- Medical Investigation of Neurodevelopmental Disorders Institute, University of California Davis, Sacramento, CA95817
| | - Eric B. Nonnecke
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA95616
| | - Arthur J. de Lorimier
- University of California Davis Medical Center, Department of Pediatrics, Sacramento, CA95817
| | - Mohamed R. Ali
- University of California Davis Medical Center, Department of Surgery, Sacramento, CA95817
| | - Renée M. Tsolis
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA95616
| | - Charles L. Bevins
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA95616
| | - Paul Ashwood
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA95616
- Medical Investigation of Neurodevelopmental Disorders Institute, University of California Davis, Sacramento, CA95817
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2
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Schlievert PM, Kilgore SH, Beck LA, Yoshida T, Klingelhutz AJ, Leung DYM. Host Cationic Antimicrobial Molecules Inhibit S. aureus Exotoxin Production. mSphere 2023; 8:e0057622. [PMID: 36598227 PMCID: PMC9942567 DOI: 10.1128/msphere.00576-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 12/02/2022] [Indexed: 01/05/2023] Open
Abstract
Innate immune molecules, including antimicrobial peptides (for example, defensins) and lysozyme, function to delay or prevent bacterial infections. These molecules are commonly found on mucosal and skin surfaces. Staphylococcus aureus is a common pathogen and causes millions of infections annually. It is well known that innate immune molecules, such as defensins and lysozyme, either poorly inhibit or do not inhibit the growth of S. aureus. Our current studies show that the α-defensin human neutrophil α-defensin-1 (HNP-1) and lysozyme inhibit exotoxin production, both hemolysins and superantigens, which are required for S. aureus infection. HNP-1 inhibited exotoxin production at concentrations as low as 0.001 μg/mL. Lysozyme inhibited exotoxin production at 0.05 to 0.5 μg/mL. Both HNP-1 and lysozyme functioned through at least one two-component system (SrrA/B). The β-defensin human β-defensin 1 (HBD-1) inhibited hemolysin but not superantigen production. The cation chelator S100A8/A9 (calprotectin), compared to EDTA, was tested for the ability to inhibit exotoxin production. EDTA at high concentrations inhibited exotoxin production; these were the same concentrations that interfered with staphylococcal growth. S100A8/A9 at the highest concentration tested (10 μg/mL) had no effect on S. aureus growth but enhanced exotoxin production. Lower concentrations had no effect on growth or exotoxin production. Lysostaphin is regularly used to lyse S. aureus. The lytic concentrations of lysostaphin were the only concentrations that also inhibited growth and exotoxin production. Our studies demonstrate that a major activity of innate defensin peptides and lysozyme is inhibition of staphylococcal exotoxin production but not inhibition of growth. IMPORTANCE Staphylococcus aureus causes large numbers of both relatively benign and serious human infections, which are mediated in large part by the organisms' secreted exotoxins. Since 1921, it has been known that lysozyme and, as shown later in the 1900s, other innate immune peptides, including human neutrophil α-defensin-1 (HNP-1) and human β-defensin 1 (HBD-1), are either not antistaphylococcal or are only weakly inhibitory to growth. Our study confirms those findings but, importantly, shows that at subgrowth inhibitory concentrations, these positively charged innate immune peptides inhibit exotoxin production, including both hemolysins and the superantigen toxic shock syndrome toxin-1. The data show that the principal activity of innate immune peptides in the host is likely to be inhibition of exotoxin production required for staphylococcal mucosal or skin colonization rather than growth inhibition.
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Affiliation(s)
- Patrick M. Schlievert
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Samuel H. Kilgore
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Lisa A. Beck
- Department of Dermatology, University of Rochester Medical Center, Rochester, New York, USA
| | - Takeshi Yoshida
- Department of Dermatology, University of Rochester Medical Center, Rochester, New York, USA
| | - Aloysius J. Klingelhutz
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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Chang XY, Zhang MW, Zhang LJ, Chai LQ. The Function and Modification of Human Defensin 5. Protein Pept Lett 2023; 30:830-840. [PMID: 37861034 DOI: 10.2174/0109298665252235230919071229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/17/2023] [Accepted: 04/19/2023] [Indexed: 10/21/2023]
Abstract
The antibacterial and antiviral functions of human defensin 5 lay the foundation for its role as a core host protective component. In addition, HD5 also has the function of inhibiting tumor proliferation and immune regulation. However, everything has two sides; cytotoxic and proinflammatory properties may exist, while HD5 performs physiological functions. Accordingly, the modification and engineering of HD5 are particularly important. Therefore, this review summarizes the role of HD5 in various aspects of host defense, as well as modification of HD5 to ameliorate the biological activity, with a view to promoting the clinical use of HD5.
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Affiliation(s)
- Xin-Yue Chang
- School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Meng-Wei Zhang
- School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Lin-Jie Zhang
- School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Lian-Qin Chai
- School of Life Sciences, Henan University, Kaifeng 475004, China
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4
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O’Brien DK, Ribot WJ, Chabot DJ, Scorpio A, Tobery SA, Jelacic TM, Wu Z, Friedlander AM. The capsule of Bacillus anthracis protects it from the bactericidal activity of human defensins and other cationic antimicrobial peptides. PLoS Pathog 2022; 18:e1010851. [PMID: 36174087 PMCID: PMC9560598 DOI: 10.1371/journal.ppat.1010851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 10/13/2022] [Accepted: 09/04/2022] [Indexed: 12/04/2022] Open
Abstract
During infection, Bacillus anthracis bacilli encounter potent antimicrobial peptides (AMPs) such as defensins. We examined the role that B. anthracis capsule plays in protecting bacilli from defensins and other cationic AMPs by comparing their effects on a fully virulent encapsulated wild type (WT) strain and an isogenic capsule-deficient capA mutant strain. We identified several human defensins and non-human AMPs that were capable of killing B. anthracis. The human alpha defensins 1–6 (HNP-1-4, HD-5-6), the human beta defensins 1–4 (HBD-1-4), and the non-human AMPs, protegrin, gramicidin D, polymyxin B, nisin, and melittin were all capable of killing both encapsulated WT and non-encapsulated capA mutant B. anthracis. However, non-encapsulated capA mutant bacilli were significantly more susceptible than encapsulated WT bacilli to killing by nearly all of the AMPs tested. We demonstrated that purified capsule bound HBD-2, HBD-3, and HNP-1 in an electrophoretic mobility shift assay. Furthermore, we determined that the capsule layer enveloping WT bacilli bound and trapped HBD-3, substantially reducing the amount reaching the cell wall. To assess whether released capsule might also play a protective role, we pre-incubated HBD-2, HBD-3, or HNP-1 with purified capsule before their addition to non-encapsulated capA mutant bacilli. We found that free capsule completely rescued the capA mutant bacilli from killing by HBD-2 and -3 while killing by HNP-1 was reduced to the level observed with WT bacilli. Together, these results suggest an immune evasion mechanism by which the capsule, both that enveloping the bacilli and released fragments, contributes to virulence by binding to and inhibiting the antimicrobial activity of cationic AMPs. Bacillus anthracis causes anthrax after spores infect the skin, respiratory tract, or gastrointestinal tract. Antimicrobial peptides (AMPs), such as defensins, are a first line of host defense that B. anthracis encounters in all of these tissues. B. anthracis bacteria are covered by a capsule that protects them from being engulfed and destroyed by phagocytic immune cells. In this study, we found that the capsule also provides protection from AMPs. An encapsulated B. anthracis strain is resistant to killing by multiple AMPs from humans and other species compared to an otherwise identical strain that is not encapsulated. By binding defensins the capsule surrounding the bacilli reduces the amount that gets to the bacterial cell wall where it can do damage. B. anthracis bacteria release large fragments of capsule in the host during infection and during growth in culture. We found that purified released capsule can bind defensins and reduce killing of non-encapsulated B. anthracis. Thus, both capsule covering the bacteria and capsule shed by the bacteria can contribute to the pathogenicity of B. anthracis by providing protection from AMPs. Our study reveals a new mechanism by which B. anthracis capsule contributes to virulence.
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Affiliation(s)
- David K. O’Brien
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Wilson J. Ribot
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Donald J. Chabot
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Angelo Scorpio
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Steven A. Tobery
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Tanya M. Jelacic
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Zhibin Wu
- Institute of Human Virology, University of Maryland Biotechnology Institute, Baltimore, Maryland, United States of America
| | - Arthur M. Friedlander
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
- Department of Medicine, Uniformed University of Health Services, Bethesda, Maryland, United States of America
- * E-mail: ,
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5
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Hu CT, Diaz K, Yang LC, Sharma A, Greenberg HB, Smith JG. VP4 Is a Determinant of Alpha-Defensin Modulation of Rotaviral Infection. J Virol 2022; 96:e0205321. [PMID: 35285683 PMCID: PMC9006894 DOI: 10.1128/jvi.02053-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/31/2022] [Indexed: 11/20/2022] Open
Abstract
Fecal-oral pathogens encounter constitutively expressed enteric alpha-defensins in the intestine during replication and transmission. Alpha-defensins can be potently antiviral and antibacterial; however, their primary sequences, the number of isoforms, and their activity against specific microorganisms often vary greatly between species, reflecting adaptation to species-specific pathogens. Therefore, alpha-defensins might influence not only microbial evolution and tissue tropism within a host but also species tropism and zoonotic potential. To investigate these concepts, we generated a panel of enteric and myeloid alpha-defensins from humans, rhesus macaques, and mice and tested their activity against group A rotaviruses, an important enteric viral pathogen of humans and animals. Rotaviral adaptation to the rhesus macaque correlated with resistance to rhesus enteric, but not myeloid, alpha-defensins and sensitivity to human alpha-defensins. While mouse rotaviral infection was increased in the presence of mouse enteric alpha-defensins, two prominent genotypes of human rotaviruses were differentially sensitive to human enteric alpha-defensins. Furthermore, the effects of cross-species alpha-defensins on human and mouse rotaviruses did not follow an obvious pattern. Thus, exposure to alpha-defensins may have shaped the evolution of some, but not all, rotaviruses. We then used a genetic approach to identify the viral attachment and penetration protein, VP4, as a determinant of alpha-defensin sensitivity. Our results provide a foundation for future studies of the VP4-dependent mechanism of defensin neutralization, highlight the species-specific activities of alpha-defensins, and focus future efforts on a broader range of rotaviruses that differ in VP4 to uncover the potential for enteric alpha-defensins to influence species tropism. IMPORTANCE Rotavirus is a leading cause of severe diarrhea in young children. Like other fecal-oral pathogens, rotaviruses encounter abundant, constitutively expressed defensins in the small intestine. These peptides are a vital part of the vertebrate innate immune system. By investigating the impact that defensins from multiple species have on the infectivity of different strains of rotavirus, we show that some rotaviral infections can be inhibited by defensins. We also found that some, but not all, rotaviruses may have evolved resistance to defensins in the intestine of their host species, and some even appropriate defensins to increase their infectivity. Because rotaviruses infect a broad range of animals and rotaviral infections are highly prevalent in children, identifying immune defenses against infection and how they vary across species and among viral genotypes is important for our understanding of the evolution, transmission, and zoonotic potential of these viruses as well as the improvement of vaccines.
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Affiliation(s)
- Ciara T. Hu
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Karina Diaz
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Linda C. Yang
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Anjali Sharma
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Harry B. Greenberg
- Department of Medicine and Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
| | - Jason G. Smith
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, USA
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6
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Xie Q, Wang Y, Zhang M, Wu S, Wei W, Xiao W, Wang Y, Zhao J, Liu N, Jin Y, Wu J, Xu P. Recombinant HNP-1 Produced by Escherichia coli Triggers Bacterial Apoptosis and Exhibits Antibacterial Activity against Drug-Resistant Bacteria. Microbiol Spectr 2022; 10:e0086021. [PMID: 35019682 PMCID: PMC8754131 DOI: 10.1128/spectrum.00860-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 12/08/2021] [Indexed: 12/14/2022] Open
Abstract
Human neutrophil peptide-1 (HNP-1) is a promising antibiotic candidate, but its clinical applications have been hampered by challenges during mass production and an inadequate understanding of its bactericidal mechanisms. In this study, we demonstrated that Escherichia coli expressing full-length preproHNP-1 secretes a soluble form of HNP-1, which can be recovered from the total cell lysate after isopropyl thio-β-d-galactoside (IPTG) induction and ultrafiltration. Label-free quantitative proteomics and co-immunoprecipitation experiments revealed that HNP-1 induces cell apoptosis in bacteria by causing DNA and membrane damage. Notably, we found that HNP-1 disrupts the DNA damage response pathway by interfering with the binding of RecA to single-stranded DNA (ssDNA). Further experiments demonstrated that HNP-1 encapsulated in liposomes inhibits the growth of methicillin-resistant Staphylococcus aureus (MRSA) and meropenem-resistant Pseudomonas aeruginosa (MRPA). These results indicated that recombinant protein expression may be a simple and cost-effective solution to produce HNP-1 and that RecA inhibition via HNP-1 may serve as an alternative strategy to counteract antibiotic resistance. IMPORTANCE Human neutrophil peptide-1 (HNP-1) is a promising antibiotic candidate, but its clinical application has been hampered by the difficulty of mass production and an inadequate understanding of its bactericidal mechanisms. In this study, we demonstrated that recombinant protein expression combined with ultrafiltration may be a simple and cost-effective solution to HNP-1 production. We further found that HNP-1 induces bacterial apoptosis and prevents its SOS repair pathway from binding to the RecA protein, which may be a new antibacterial mechanism. In addition, we showed that HNP-1 encapsulated in liposomes inhibits the growth of methicillin-resistant Staphylococcus aureus (MRSA) and meropenem-resistant Pseudomonas aeruginosa (MRPA). These results provide new insights into the production and antibacterial mechanism of HNP-1, both of which may promote its clinical application.
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Affiliation(s)
- Qi Xie
- School of Basic Medical Science, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery of Ministry of Education and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences Beijing, Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Institute of Lifeomics, Beijing, China
- Department of Neurology, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Yin Wang
- School of Basic Medical Science, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery of Ministry of Education and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences Beijing, Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Institute of Lifeomics, Beijing, China
| | - Mengmeng Zhang
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, Beijing, China
| | - Shujia Wu
- School of Basic Medical Science, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery of Ministry of Education and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences Beijing, Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Institute of Lifeomics, Beijing, China
| | - Wei Wei
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences Beijing, Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Institute of Lifeomics, Beijing, China
| | - Weidi Xiao
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences Beijing, Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Institute of Lifeomics, Beijing, China
| | - Yihao Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences Beijing, Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Institute of Lifeomics, Beijing, China
| | - Jinchao Zhao
- School of Basic Medical Science, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery of Ministry of Education and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Nan Liu
- School of Basic Medical Science, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery of Ministry of Education and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Yiguang Jin
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, Beijing, China
| | - Junzhu Wu
- School of Basic Medical Science, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery of Ministry of Education and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Ping Xu
- School of Basic Medical Science, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery of Ministry of Education and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences Beijing, Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Institute of Lifeomics, Beijing, China
- Anhui Medical University, Hefei, China
- School of Public Health, China Medical University, Shenyang, China
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7
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Kling C, Pulliainen AT, Barth H, Ernst K. Human Peptides α-Defensin-1 and -5 Inhibit Pertussis Toxin. Toxins (Basel) 2021; 13:toxins13070480. [PMID: 34357952 PMCID: PMC8310310 DOI: 10.3390/toxins13070480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/01/2021] [Accepted: 07/09/2021] [Indexed: 01/13/2023] Open
Abstract
Bordetella pertussis causes the severe childhood disease whooping cough, by releasing several toxins, including pertussis toxin (PT) as a major virulence factor. PT is an AB5-type toxin, and consists of the enzymatic A-subunit PTS1 and five B-subunits, which facilitate binding to cells and transport of PTS1 into the cytosol. PTS1 ADP-ribosylates α-subunits of inhibitory G-proteins (Gαi) in the cytosol, which leads to disturbed cAMP signaling. Since PT is crucial for causing severe courses of disease, our aim is to identify new inhibitors against PT, to provide starting points for novel therapeutic approaches. Here, we investigated the effect of human antimicrobial peptides of the defensin family on PT. We demonstrated that PTS1 enzyme activity in vitro was inhibited by α-defensin-1 and -5, but not β-defensin-1. The amount of ADP-ribosylated Gαi was significantly reduced in PT-treated cells, in the presence of α-defensin-1 and -5. Moreover, both α-defensins decreased PT-mediated effects on cAMP signaling in the living cell-based interference in the Gαi-mediated signal transduction (iGIST) assay. Taken together, we identified the human peptides α-defensin-1 and -5 as inhibitors of PT activity, suggesting that these human peptides bear potential for developing novel therapeutic strategies against whooping cough.
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Affiliation(s)
- Carolin Kling
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, 89081 Ulm, Germany; (C.K.); (H.B.)
| | - Arto T. Pulliainen
- Institute of Biomedicine, Research Unit for Infection and Immunity, University of Turku, FI-20520 Turku, Finland;
| | - Holger Barth
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, 89081 Ulm, Germany; (C.K.); (H.B.)
| | - Katharina Ernst
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, 89081 Ulm, Germany; (C.K.); (H.B.)
- Correspondence:
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Abdeen S, Bdeir K, Abu‐Fanne R, Maraga E, Higazi M, Khurram N, Feldman M, Deshpande C, Litzky LA, Heyman SN, Montone KT, Cines DB, Higazi AA. Alpha-defensins: risk factor for thrombosis in COVID-19 infection. Br J Haematol 2021; 194:44-52. [PMID: 34053084 PMCID: PMC8239944 DOI: 10.1111/bjh.17503] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 12/13/2022]
Abstract
The inflammatory response to SARS/CoV-2 (COVID-19) infection may contribute to the risk of thromboembolic complications. α-Defensins, antimicrobial peptides released from activated neutrophils, are anti-fibrinolytic and prothrombotic in vitro and in mouse models. In this prospective study of 176 patients with COVID-19 infection, we found that plasma levels of α-defensins were elevated, tracked with disease progression/mortality or resolution and with plasma levels of interleukin-6 (IL-6) and D-dimers. Immunohistochemistry revealed intense deposition of α-defensins in lung vasculature and thrombi. IL-6 stimulated the release of α-defensins from neutrophils, thereby accelerating coagulation and inhibiting fibrinolysis in human blood, imitating the coagulation pattern in COVID-19 patients. The procoagulant effect of IL-6 was inhibited by colchicine, which blocks neutrophil degranulation. These studies describe a link between inflammation and the risk of thromboembolism, and they identify a potential new approach to mitigate this risk in patients with COVID-19 and potentially in other inflammatory prothrombotic conditions.
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Affiliation(s)
- Suhair Abdeen
- Department of Clinical BiochemistryHadassah‐Hebrew UniversityJerusalemIL‐91120Israel
| | - Khalil Bdeir
- Departments of Pathology and Laboratory MedicineUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPA19104USA
| | - Rami Abu‐Fanne
- Heart InstituteHillel Yaffe Medical Center Affiliated with Rappaport Faculty of MedicineTechnion‐Israel Institute of TechnologyHaifaIsrael
| | - Emad Maraga
- Heart InstituteHillel Yaffe Medical Center Affiliated with Rappaport Faculty of MedicineTechnion‐Israel Institute of TechnologyHaifaIsrael
| | - Mohamed Higazi
- Department of Clinical BiochemistryHadassah‐Hebrew UniversityJerusalemIL‐91120Israel
| | - Nigar Khurram
- Departments of Pathology and Laboratory MedicineUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPA19104USA
| | - Michael Feldman
- Departments of Pathology and Laboratory MedicineUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPA19104USA
| | - Charuhas Deshpande
- Departments of Pathology and Laboratory MedicineUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPA19104USA
| | - Leslie A. Litzky
- Departments of Pathology and Laboratory MedicineUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPA19104USA
| | - Samuel N. Heyman
- Department of MedicineHadassah University HospitalMt. ScopusJerusalemIL‐91240Israel
| | - Kathleen T. Montone
- Departments of Pathology and Laboratory MedicineUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPA19104USA
| | - Douglas B. Cines
- Departments of Pathology and Laboratory MedicineUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPA19104USA
- Department of MedicineUniversity of Pennsylvania‐ Perelman School of MedicinePhiladelphiaPA19104USA
| | - Abd Al‐Roof Higazi
- Department of Clinical BiochemistryHadassah‐Hebrew UniversityJerusalemIL‐91120Israel
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Moazzezy N, Asadi Karam MR, Rafati S, Bouzari S, Oloomi M. Inhibition and eradication activity of truncated α-defensin analogs against multidrug resistant uropathogenic Escherichia coli biofilm. PLoS One 2020; 15:e0235892. [PMID: 32663201 PMCID: PMC7360030 DOI: 10.1371/journal.pone.0235892] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 06/25/2020] [Indexed: 01/24/2023] Open
Abstract
Today the development of antibiotic resistance, especially in the treatment of bacterial infections associated with biofilms, has led to increasing the importance of antimicrobial peptides (AMPs). In this work, antimicrobial and synergistic activity of three truncated HNP-1 analogs (2Abz14S29, 2Abz23S29, and HNP1ΔC18A) with β-lactam (amoxicillin and cefixime) and fluoroquinolones (ciprofloxacin and norfloxacin) antibiotics against multidrug-resistant (MDR) uropathogenic E. coli clinical isolates were evaluated. The anti-biofilm potential of peptides at different stages was also investigated. All peptides exhibited additive activity just with β-lactam antibiotics in a checkerboard synergy assay. Inhibition and eradication of MDR uropathogenic E. coli biofilm were shown by all test peptides at different concentrations. Thus, truncated HNP-1 analogs (2Abz14S29, 2Abz23S29, and HNP1ΔC18A) may have the potential for the treatment of urinary tract infections (UTIs) caused by biofilm-forming MDR uropathogenic E. coli.
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Affiliation(s)
- Neda Moazzezy
- Molecular Biology Department, Pasteur Institute of Iran, Tehran, Iran
| | | | - Sima Rafati
- Immunotherapy and Leishmania Vaccine Research Department, Pasteur Institute of Iran, Tehran, Iran
| | - Saeid Bouzari
- Molecular Biology Department, Pasteur Institute of Iran, Tehran, Iran
- * E-mail: (SB); (MO)
| | - Mana Oloomi
- Molecular Biology Department, Pasteur Institute of Iran, Tehran, Iran
- * E-mail: (SB); (MO)
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10
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Panjeta A, Preet S. Anticancer potential of human intestinal defensin 5 against 1, 2-dimethylhydrazine dihydrochloride induced colon cancer: A therapeutic approach. Peptides 2020; 126:170263. [PMID: 31981594 DOI: 10.1016/j.peptides.2020.170263] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/17/2020] [Accepted: 01/21/2020] [Indexed: 12/12/2022]
Abstract
The escalating predicament of multidrug resistant cancer cells and associated side effects of conventional chemotherapy necessitates the exploration of alternative anticancer therapies. The present study evaluated anticancer therapeutic potential of human defensin 5 (HD-5) against colon cancer. The in vivo anticancer efficacy of HD-5 against 1,2-dimethylhydrazine (DMH) induced colon cancer was elucidated in terms of tumor biostatistics, number of aberrant crypt foci (ACF), in situ apoptosis assay,changes in morphological as well as histological architecture of colon(s). The direct interaction of peptide was investigated by incubating peptide with normal and/or cancerous colonocytes followed by phase contrast, Hoechst 3342 and AO/PI staining as well as confocal microscopy. Changes in membrane dynamics were evaluated by MC 540 and N-NBD-PE staining. In vivo decrease(s) in tumor parameters, number of aberrant crypt foci along with marked increase in the rate of apoptosis was observed.H&E staining revealed neutrophils infiltration and restoration of normal architecture in treated colon(s) which was consistent with scanning electron microscopic observations. Furthermore, non-membranolytic mechanism was found to be acquired by peptide as it could traverse cell membrane gaining access to nucleus and cytoplasm thereby disintegrating cellular architecture. MC 540 and NBD-PE staining revealed that peptide could bind to cancerous cells by taking advantage of altered fluidity levels. Our results indicated that HD-5 exhibited strong cancer cell killing and does not affect normal host cells. The peptide can be exploited as promising option to combat developing menace of colon cancer and/or can at least be used as an adjunct to present day chemotherapies.
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Affiliation(s)
- Anshul Panjeta
- Department of Biophysics, Basic Medical Sciences, Block II, Panjab University, Sector 25, Chandigarh, 160014, India
| | - Simran Preet
- Department of Biophysics, Basic Medical Sciences, Block II, Panjab University, Sector 25, Chandigarh, 160014, India.
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11
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Sharma R, Raghav R, Priyanka K, Rishi P, Sharma S, Srivastava S, Verma I. Exploiting chitosan and gold nanoparticles for antimycobacterial activity of in silico identified antimicrobial motif of human neutrophil peptide-1. Sci Rep 2019; 9:7866. [PMID: 31133658 PMCID: PMC6536545 DOI: 10.1038/s41598-019-44256-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 05/13/2019] [Indexed: 12/13/2022] Open
Abstract
The upsurge of drug resistant tuberculosis is major health threat globally. To counteract, antimicrobial peptides are being explored as possible alternatives. However, certain limitations of peptide-based drugs such as potential toxicity, high cost and relatively low stability need to be addressed to enhance their clinical applicability. Use of computer predicted short active motifs of AMPs along with nanotechnology could not only overcome the limitations of AMPs but also potentiate their antimicrobial activity. Therefore, present study was proposed to in silico identify short antimicrobial motif (Pep-H) of human neutrophil peptide-1 (HNP-1) and explore its antimycobacterial activity in free form and using nanoparticles-based delivery systems. Based on colony forming unit analysis, motif Pep-H led to killing of more than 90% M. tb in vitro at 10 μg/ml, whereas, similar activity against intracellularly growing M. tb was observed at 5 μg/ml only. Thereafter, chitosan (244 nm) and gold nanoparticles (20 nm) were prepared for Pep-H with both the formulations showing minimal effects on the viability of human monocyte derived macrophages (MDMs) and RBC integrity. The antimycobacterial activity of Pep-H against intracellular mycobacteria was enhanced in both the nanoformulations as evident by significant reduction in CFU (>90%) at 5-10 times lower concentrations than that observed for free Pep-H. Thus, Pep-H is an effective antimycobacterial motif of HNP-1 and its activity is further enhanced by chitosan and gold nanoformulations.
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Affiliation(s)
- Richa Sharma
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, Chandigarh, India
- Albert Einstein College of Medicine, Bronx, New York, USA
| | - Ragini Raghav
- Department of Biotechnology, Jaypee Institute of Information Technology, Noida, Uttar Pradesh, India
| | - Kumari Priyanka
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Praveen Rishi
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Sadhna Sharma
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Sudha Srivastava
- Department of Biotechnology, Jaypee Institute of Information Technology, Noida, Uttar Pradesh, India
| | - Indu Verma
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
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12
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Zou G, de Leeuw E. Neutralization of Pseudomonas auruginosa Exotoxin A by human neutrophil peptide 1. Biochem Biophys Res Commun 2018; 501:454-457. [PMID: 29738776 DOI: 10.1016/j.bbrc.2018.05.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 05/02/2018] [Indexed: 01/01/2023]
Abstract
Pseudomonas aeruginosa produces a large number of virulence factors, including the extracellular protein, Exotoxin A (ETA). Human Neutrophil Peptide 1 (HNP1) neutralizes the Exotoxin A. HNP1 belongs to the family of α-defensins, small effector peptides of the innate immune system that combat against microbial infections. Neutralization of bacterial toxins such as ETA by HNP1 is a novel biological function in addition to direct killing of bacteria. In this study, we report on the interaction between HNP-1 and Exotoxin A at the molecular level to allow for the design and development of potent antibacterial peptides as alternatives to classical antibiotics.
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Affiliation(s)
- Guozhang Zou
- U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, USA
| | - Erik de Leeuw
- Institute of Human Virology of the University of Maryland Baltimore School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA.
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13
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Mathew B, Nagaraj R. Variations in the interaction of human defensins with Escherichia coli: Possible implications in bacterial killing. PLoS One 2017; 12:e0175858. [PMID: 28423004 PMCID: PMC5397029 DOI: 10.1371/journal.pone.0175858] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 03/31/2017] [Indexed: 01/08/2023] Open
Abstract
Human α and β-defensins are cationic antimicrobial peptides characterized by three disulfide bonds with a triple stranded β-sheet motif. It is presumed that interaction with the bacterial cell surface and membrane permeabilization by defensins is an important step in the killing process. In this study, we have compared interactions of three human α-defensins HNP3, HNP4, HD5 and human β-defensins HBD1-4 that are active against Escherichia coli, with its cell surface and inner membrane as well as negatively charged model membranes. We have also included the inactive α-defensin HD6 in the study. Among the α-defensins, HNP4, HD5 and HD6 were more effective in increasing the zeta potential as compared to HNP3. Among the β-defensins, HBD1 was the least effective in increasing the zeta potential. The zeta potential modulation data indicate variations in the surface charge neutralizing ability of α- and β-defensins. Comparison of E. coli inner membrane and model membrane permeabilizing abilities indicated that HD5, HD6 and HBD1 do not permeabilize membranes. Although HBD4 does not permeabilize model membranes, considerable damage to the inner membrane of E. coli is observed. Our data indicate that mammalian defensins do not kill E. coli by a simple mechanism involving membrane permeabilization though their antibacterial potencies are very similar.
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Affiliation(s)
- Basil Mathew
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
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14
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Brook M, Tomlinson GH, Miles K, Smith RWP, Rossi AG, Hiemstra PS, van 't Wout EFA, Dean JLE, Gray NK, Lu W, Gray M. Neutrophil-derived alpha defensins control inflammation by inhibiting macrophage mRNA translation. Proc Natl Acad Sci U S A 2016; 113:4350-5. [PMID: 27044108 PMCID: PMC4843457 DOI: 10.1073/pnas.1601831113] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Neutrophils are the first and most numerous cells to arrive at the site of an inflammatory insult and are among the first to die. We previously reported that alpha defensins, released from apoptotic human neutrophils, augmented the antimicrobial capacity of macrophages while also inhibiting the biosynthesis of proinflammatory cytokines. In vivo, alpha defensin administration protected mice from inflammation, induced by thioglychollate-induced peritonitis or following infection withSalmonella entericaserovar Typhimurium. We have now dissected the antiinflammatory mechanism of action of the most abundant neutrophil alpha defensin, Human Neutrophil Peptide 1 (HNP1). Herein we show that HNP1 enters macrophages and inhibits protein translation without inducing the unfolded-protein response or affecting mRNA stability. In a cell-free in vitro translation system, HNP1 powerfully inhibited both cap-dependent and cap-independent mRNA translation while maintaining mRNA polysomal association. This is, to our knowledge, the first demonstration of a peptide released from one cell type (neutrophils) directly regulating mRNA translation in another (macrophages). By preventing protein translation, HNP1 functions as a "molecular brake" on macrophage-driven inflammation, ensuring both pathogen clearance and the resolution of inflammation with minimal bystander tissue damage.
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Affiliation(s)
- Matthew Brook
- Medical Research Council (MRC) Centre for Reproductive Health, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland
| | - Gareth H Tomlinson
- MRC Centre for Inflammation Research, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland
| | - Katherine Miles
- MRC Centre for Inflammation Research, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland
| | - Richard W P Smith
- Medical Research Council (MRC) Centre for Reproductive Health, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland
| | - Adriano G Rossi
- MRC Centre for Inflammation Research, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland
| | - Pieter S Hiemstra
- Department of Pulmonology, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
| | - Emily F A van 't Wout
- Department of Pulmonology, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
| | - Jonathan L E Dean
- Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, United Kingdom
| | - Nicola K Gray
- Medical Research Council (MRC) Centre for Reproductive Health, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland
| | - Wuyuan Lu
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Mohini Gray
- MRC Centre for Inflammation Research, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, Scotland;
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15
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Abstract
Human α-defensin 5 (HD5) exhibits broad spectrum antimicrobial activity and plays an important role in mucosal immunity of the small intestine. Although there have been several studies, the structural requirements for activity and mechanism of bacterial killing is yet to be established unequivocally. In this study, we have investigated the antimicrobial activity of HD5 and linear analogs. Cysteine deletions attenuated the antibacterial activity considerably. Candidacidal activity was affected to a lesser extent. Fatty acid conjugated linear analogs showed antimicrobial activity comparable activity to HD5. Effective surface charge neutralization of bacteria was observed for HD5 as compared to the non-fatty acylated linear analogs. Our results show that HD5 and non-fatty acylated linear analogs enter the bacterial cytoplasm without causing damage to the bacterial inner membrane. Although fatty acylated peptides exhibited antimicrobial activity comparable to HD5, their mechanism of action involved permeabilization of the Escherichia coli inner membrane. HD5 and analogs had the ability to bind plasmid DNA. HD5 had greater binding affinity to plasmid DNA as compared to the analogs. The three dimensional structure of HD5 favors greater interaction with the bacterial cell surface and also with DNA. Antibacterial activity of HD5 involves entry into bacterial cytoplasm and binding to DNA which would result in shut down of the bacterial metabolism leading to cell death. We show how a moderately active linear peptide derived from the α-defensin HD5 can be engineered to enhance antimicrobial activity almost comparable to the native peptide.
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Affiliation(s)
- Basil Mathew
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Ramakrishnan Nagaraj
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.
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16
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Merriman JA, Nemeth KA, Schlievert PM. Novel antimicrobial peptides that inhibit gram positive bacterial exotoxin synthesis. PLoS One 2014; 9:e95661. [PMID: 24748386 PMCID: PMC3991719 DOI: 10.1371/journal.pone.0095661] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 03/29/2014] [Indexed: 01/31/2023] Open
Abstract
Gram-positive bacteria, such as Staphylococcus aureus, cause serious human illnesses through combinations of surface virulence factors and secretion of exotoxins. Our prior studies using the protein synthesis inhibitor clindamycin and signal transduction inhibitors glycerol monolaurate and α-globin and β-globin chains of hemoglobin indicate that their abilities to inhibit exotoxin production by S. aureus are separable from abilities to inhibit growth of the organism. Additionally, our previous studies suggest that inhibition of exotoxin production, in absence of ability to kill S. aureus and normal flora lactobacilli, will prevent colonization by pathogenic S. aureus, while not interfering with lactobacilli colonization. These disparate activities may be important in development of novel anti-infective agents that do not alter normal flora. We initiated studies to explore the exotoxin-synthesis-inhibition activity of hemoglobin peptides further to develop potential agents to prevent S. aureus infections. We tested synthesized α-globin chain peptides, synthetic variants of α-globin chain peptides, and two human defensins for ability to inhibit exotoxin production without significantly inhibiting S. aureus growth. All of these peptides were weakly or not inhibitory to bacterial growth. However, the peptides were inhibitory to exotoxin production with increasing activity dependent on increasing numbers of positively-charged amino acids. Additionally, the peptides could be immobilized on agarose beads or have amino acid sequences scrambled and still retain exotoxin-synthesis-inhibition. The peptides are not toxic to human vaginal epithelial cells and do not inhibit growth of normal flora L. crispatus. These peptides may interfere with plasma membrane signal transduction in S. aureus due to their positive charges.
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Affiliation(s)
- Joseph A. Merriman
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Kimberly A. Nemeth
- The Procter & Gamble Company, Cincinnati, Ohio, United States of America
| | - Patrick M. Schlievert
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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17
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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18
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Thomassin JL, Lee MJ, Brannon JR, Sheppard DC, Gruenheid S, Le Moual H. Both group 4 capsule and lipopolysaccharide O-antigen contribute to enteropathogenic Escherichia coli resistance to human α-defensin 5. PLoS One 2013; 8:e82475. [PMID: 24324796 PMCID: PMC3853201 DOI: 10.1371/journal.pone.0082475] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 11/02/2013] [Indexed: 12/18/2022] Open
Abstract
Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) are food-borne pathogens that colonize the small intestine and colon, respectively. To cause disease, these pathogens must overcome the action of different host antimicrobial peptides (AMPs) secreted into these distinct niches. We have shown previously that EHEC expresses high levels of the OmpT protease to inactivate the human cathelicidin LL-37, an AMP present in the colon. In this study, we investigate the mechanisms used by EPEC to resist human α-defensin 5 (HD-5), the most abundant AMP in the small intestine. Quantitative PCR was used to measure transcript levels of various EPEC surface structures. High transcript levels of gfcA, a gene required for group 4 capsule (G4C) production, were observed in EPEC, but not in EHEC. The unencapsulated EPEC ∆gfcA and EHEC wild-type strains were more susceptible to HD-5 than EPEC wild-type. Since the G4C is composed of the same sugar repeats as the lipopolysaccharide O-antigen, an -antigen ligase (waaL) deletion mutant was generated in EPEC to assess its role in HD-5 resistance. The ∆waaL EPEC strain was more susceptible to HD-5 than both the wild-type and ∆gfcA strains. The ∆gfcA∆waaL EPEC strain was not significantly more susceptible to HD-5 than the ∆waaL strain, suggesting that the absence of -antigen influences G4C formation. To determine whether the G4C and -antigen interact with HD-5, total polysaccharide was purified from wild-type EPEC and added to the ∆gfcA∆waaL strain in the presence of HD-5. The addition of exogenous polysaccharide protected the susceptible strain against HD-5 killing in a dose-dependent manner, suggesting that HD-5 binds to the polysaccharides present on the surface of EPEC. Altogether, these findings indicate that EPEC relies on both the G4C and the -antigen to resist the bactericidal activity of HD-5.
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Affiliation(s)
- Jenny-Lee Thomassin
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Mark J. Lee
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - John R. Brannon
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Donald C. Sheppard
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Microbiome and Disease Tolerance Centre, McGill University, Montreal, Quebec, Canada
| | - Samantha Gruenheid
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Microbiome and Disease Tolerance Centre, McGill University, Montreal, Quebec, Canada
| | - Hervé Le Moual
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Microbiome and Disease Tolerance Centre, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
- * E-mail:
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19
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Dabirian S, Taslimi Y, Zahedifard F, Gholami E, Doustdari F, Motamedirad M, Khatami S, Azadmanesh K, Nylen S, Rafati S. Human neutrophil peptide-1 (HNP-1): a new anti-leishmanial drug candidate. PLoS Negl Trop Dis 2013; 7:e2491. [PMID: 24147170 PMCID: PMC3798388 DOI: 10.1371/journal.pntd.0002491] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 09/08/2013] [Indexed: 11/19/2022] Open
Abstract
The toxicity of available drugs for treatment of leishmaniasis, coupled with emerging drug resistance, make it urgent to find new therapies. Antimicrobial peptides (AMPs) have a strong broad-spectrum antimicrobial activity with distinctive modes of action and are considered as promising therapeutic agents. The defensins, members of the large family of AMPs, are immunomodulatory molecules and important components of innate immune system. Human neutrophil peptide-1 (HNP-1), which is produced by neutrophils, is one of the most potent defensins. In this study, we described anti-parasitic activity of recombinant HNP-1 (rHNP-1) against Leishmania major promastigotes and amastigotes. Furthermore, we evaluated the immunomodulatory effect of rHNP-1 on parasite-infected neutrophils and how neutrophil apoptosis was affected. Our result showed that neutrophils isolated from healthy individuals were significantly delayed in the onset of apoptosis following rHNP-1 treatment. Moreover, there was a noteworthy increase in dying cells in rHNP-1- and/or CpG–treated neutrophils in comparison with untreated cells. There is a considerable increase in TNF-α production from rHNP-1-treated neutrophils and decreased level of TGF-β concentration, a response that should potentiate the immune system against parasite invasion. In addition, by using real-time polymerase chain reaction (real-time PCR), we showed that in vitro infectivity of Leishmania into neutrophils is significantly reduced following rHNP-1 treatment compared to untreated cells. In Iran, cutaneous leishmaniasis (CL) is a widespread and highly endemic disease in young individuals. To date, treatment strategy is based on chemotherapy accompanied with high incidence of toxicity and drug resistance. Distinctive mode of action of defensins (members of antimicrobial peptides) with low susceptibility to resistance and low toxicity to mammalian cells makes them suitable candidates for anti-leishmanial agents. The most active human defensin is human neutrophil peptide-1 (HNP-1) produced by neutrophils; the first effector cells during Leishmania infection. In this work, we used recombinant HNP-1 (rHNP-1) against both the promastigote and amastigote forms of Leishmania (L.) major. Furthermore, immunomodulatory effect of rHNP-1 on Leishmania-infected neutrophils was investigated. Our result showed that rHNP-1 has anti-parasitic effect against L. major promastigotes and amastigotes and also reduces infectivity rate of Leishmania-infected neutrophils. Moreover, assessment of cytokine production from Leishmania-infected neutrophils reveals an increase in TNF-α and a decrease in TGF-β production after rHNP-1 treatment; a cytokine pattern anticipated to facilitate control of parasites. The immunomodulatory effect of rHNP-1 on cytokine production from parasite-infected neutrophils besides its direct effect on free parasites is considered as promising step towards developing new anti-leishmanial agents.
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Affiliation(s)
- Sara Dabirian
- Molecular Immunology and Vaccine Research Laboratory, Pasteur Institute of Iran, Tehran, Iran
| | - Yasaman Taslimi
- Molecular Immunology and Vaccine Research Laboratory, Pasteur Institute of Iran, Tehran, Iran
| | - Farnaz Zahedifard
- Molecular Immunology and Vaccine Research Laboratory, Pasteur Institute of Iran, Tehran, Iran
| | - Elham Gholami
- Molecular Immunology and Vaccine Research Laboratory, Pasteur Institute of Iran, Tehran, Iran
| | - Fatemeh Doustdari
- Molecular Immunology and Vaccine Research Laboratory, Pasteur Institute of Iran, Tehran, Iran
| | | | - Shohreh Khatami
- Biochemistry Department, Pasteur Institute of Iran, Tehran, Iran
| | | | - Susanne Nylen
- Department of Microbiology Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Sima Rafati
- Molecular Immunology and Vaccine Research Laboratory, Pasteur Institute of Iran, Tehran, Iran
- * E-mail: ,
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Bai LL, Yin WB, Chen YH, Niu LL, Sun YR, Zhao SM, Yang FQ, Wang RRC, Wu Q, Zhang XQ, Hu ZM. A new strategy to produce a defensin: stable production of mutated NP-1 in nitrate reductase-deficient Chlorella ellipsoidea. PLoS One 2013; 8:e54966. [PMID: 23383016 PMCID: PMC3557228 DOI: 10.1371/journal.pone.0054966] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Accepted: 12/17/2012] [Indexed: 11/18/2022] Open
Abstract
Defensins are small cationic peptides that could be used as the potential substitute for antibiotics. However, there is no efficient method for producing defensins. In this study, we developed a new strategy to produce defensin in nitrate reductase (NR)-deficient C. ellipsoidea (nrm-4). We constructed a plant expression vector carrying mutated NP-1 gene (mNP-1), a mature α-defensin NP-1 gene from rabbit with an additional initiator codon in the 5′-terminus, in which the selection markers were NptII and NR genes. We transferred mNP-1 into nrm-4 using electroporation and obtained many transgenic lines with high efficiency under selection chemicals G418 and NaNO3. The mNP-1 was characterized using N-terminal sequencing after being isolated from transgenic lines. Excitingly, mNP-1 was produced at high levels (approximately 11.42 mg/l) even after 15 generations of continuous fermentation. In addition, mNP-1 had strong activity against Escherichia coli at 5 µg/ml. This research developed a new method for producing defensins using genetic engineering.
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Affiliation(s)
- Li-Li Bai
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Wei-Bo Yin
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Yu-Hong Chen
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Li-Li Niu
- Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Yong-Ru Sun
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Shi-Min Zhao
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Fu-Quan Yang
- Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Richard R.-C. Wang
- USDA-ARS, FRRL, Utah State University, Logan, Utah, United States of America
| | - Qing Wu
- Polo Biology Science Park Co., Ltd., Beijing, People’s Republic of China
| | - Xiang-Qi Zhang
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Zan-Min Hu
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, People’s Republic of China
- * E-mail:
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21
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Furci L, Tolazzi M, Sironi F, Vassena L, Lusso P. Inhibition of HIV-1 infection by human α-defensin-5, a natural antimicrobial peptide expressed in the genital and intestinal mucosae. PLoS One 2012; 7:e45208. [PMID: 23028850 PMCID: PMC3459904 DOI: 10.1371/journal.pone.0045208] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 08/17/2012] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND α-defensin-5 (HD5) is a key effector of the innate immune system with broad anti-bacterial and anti-viral activities. Specialized epithelial cells secrete HD5 in the genital and gastrointestinal mucosae, two anatomical sites that are critically involved in HIV-1 transmission and pathogenesis. We previously found that human neutrophil defensins (HNP)-1 and -2 inhibit HIV-1 entry by specific bilateral interaction both with the viral envelope and with its primary cellular receptor, CD4. Despite low amino acid identity, human defensin-5 (HD5) shares with HNPs a high degree of structural homology. METHODOLOGY/PRINCIPAL FINDINGS Here, we demonstrate that HD5 inhibits HIV-1 infection of primary CD4(+) T lymphocytes at low micromolar concentration under serum-free and low-ionic-strength conditions similar to those occurring in mucosal fluids. Blockade of HIV-1 infection was observed with both primary and laboratory-adapted strains and was independent of the viral coreceptor-usage phenotype. Similar to HNPs, HD5 inhibits HIV-1 entry into the target cell by interfering with the reciprocal interaction between the external envelope glycoprotein, gp120, and CD4. At high concentrations, HD5 was also found to downmodulate expression of the CXCR4 coreceptor, but not of CCR5. Consistent with its broad spectrum of activity, antibody competition studies showed that HD5 binds to a region overlapping with the CD4- and coreceptor-binding sites of gp120, but not to the V3 loop region, which contains the major determinants of coreceptor-usage specificity. CONCLUSION/SIGNIFICANCE These findings provide new insights into the first line of immune defense against HIV-1 at the mucosal level and open new perspectives for the development of preventive and therapeutic strategies.
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Affiliation(s)
- Lucinda Furci
- Unit of Human Virology, Department of Biological and Technological Research, San Raffaele Scientific Institute, Milan, Italy.
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22
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Schlusselhuber M, Jung S, Bruhn O, Goux D, Leippe M, Leclercq R, Laugier C, Grötzinger J, Cauchard J. In vitro potential of equine DEFA1 and eCATH1 as alternative antimicrobial drugs in rhodococcosis treatment. Antimicrob Agents Chemother 2012; 56:1749-55. [PMID: 22232283 PMCID: PMC3318344 DOI: 10.1128/aac.05797-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 12/30/2011] [Indexed: 11/20/2022] Open
Abstract
Rhodococcus equi, the causal agent of rhodococcosis, is a severe pathogen of foals but also of immunodeficient humans, causing bronchopneumonia. The pathogen is often found together with Klebsiella pneumoniae or Streptococcus zooepidemicus in foals. Of great concern is the fact that some R. equi strains are already resistant to commonly used antibiotics. In the present study, we evaluated the in vitro potential of two equine antimicrobial peptides (AMPs), eCATH1 and DEFA1, as new drugs against R. equi and its associated pathogens. The peptides led to growth inhibition and death of R. equi and S. zooepidemicus at low micromolar concentrations. Moreover, eCATH1 was able to inhibit growth of K. pneumoniae. Both peptides caused rapid disruption of the R. equi membrane, leading to cell lysis. Interestingly, eCATH1 had a synergic effect together with rifampin. Furthermore, eCATH1 was not cytotoxic against mammalian cells at bacteriolytic concentrations and maintained its high killing activity even at physiological salt concentrations. Our data suggest that equine AMPs, especially eCATH1, may be promising candidates for alternative drugs to control R. equi in mono- and coinfections.
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Affiliation(s)
- Margot Schlusselhuber
- Bacteriology and Parasitology Unit, Dozulé Laboratory for Equine Diseases, ANSES, Goustranville, Dozulé, France.
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Wang F, Sun B, Li H, Yin LR. [Inhibitory effects on Candida albicans of vagina cells transferred with antimicrobial peptide LL-37 and human defensin 5 recombinant plasmids]. Zhonghua Fu Chan Ke Za Zhi 2012; 47:205-211. [PMID: 22781073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
OBJECTIVE To evaluate the inhibitory effects on Candida albicans of vagina cells transferred with antimicrobial peptide LL-37 and human defensin 5 (HD5) recombinant plasmids and observe secretion of IL-8. METHODS (1) The epithelial cells from female vagina were culture primarily. The pcDNA3.1(+)/HD5-EGFP and pcDNA3.1(+)/LL-37-EGFP eukaryotic recombinant plasmids were separately or jointly transferred into the fourth generation of vaginal epithelial cells. Two test groups were defined: one test group was no Candida albicans group including four subgroups which were untransferred group, HD5 group transferred with pcDNA3.1(+)/HD5-EGFP, LL-37 group transferred with pcDNA3.1(+)/LL-37-EGFP, combining transferring group transferred with pcDNA3.1(+)/HD5-EGFP and pcDNA3.1(+)/LL-37-EGFP; the other test group was with Candida albicans group which the Candida albicans were coincubated with the four subgroups described above. (2) For examination of cytokines and chemokines, at 6, 12, 24 and 48 hours, the supernatant of every group was collected. ELISA was applied to detect the levels of LL-37, HD5 and IL-8. At each time point, the growth inhibition of Candida albicans was calculated by glucose consumption testing. RESULTS (1) The max level of LL-37, HD5 and IL-8 reached max level after being transferred for 24 hours, then showed decreasing trend. The secretion of LL-37, HD5 and IL-8 was significant higher in combining transferring group in Candida albicans group than other groups, and the secretion level of LL-37, HD5 and IL-8 was (100.16 ± 0.81) ng/ml, (58.50 ± 2.08) µg/ml and (101.03 ± 1.59) pg/ml (P < 0.01). (2) In different time point, the absorbance of each subgroup without Candida albicans declined slowly, and there were no statistically significant difference (P > 0.05), as while as in LL-37 subgroup and HD5 subgroup with Candida albicans. In group with Candida albicans, the absorbance of combining transferring subgroup were 3.210 ± 0.010, 3.150 ± 0.030, 3.099 ± 0.030 and 2.970 ± 0.040 at 6, 12, 24 and 48 hours, respectively, which was significantly higher than those in the other cells (P < 0.01), and the declined trend was the slowest. CONCLUSIONS The antifungal ability of vaginal epithelial cell became stronger after being transferred with LL-37 and HD5 recombinant plasmids. LL-37 and HD5 could also possess immunomodulatory activity and induce chemokine IL-8 production.
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Affiliation(s)
- Fang Wang
- Department of Gynecology, Second Hospital of Tianjin Medical University, Tianjin, China
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Vijayan S, Imani J, Tanneeru K, Guruprasad L, Kogel KH, Kirti PB. Enhanced antifungal and insect α-amylase inhibitory activities of Alpha-TvD1, a peptide variant of Tephrosia villosa defensin (TvD1) generated through in vitro mutagenesis. Peptides 2012; 33:220-9. [PMID: 22244814 DOI: 10.1016/j.peptides.2011.12.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 12/27/2011] [Accepted: 12/29/2011] [Indexed: 11/29/2022]
Abstract
TvD1 is a small, cationic, and highly stable defensin from the weedy legume, Tephrosia villosa with demonstrated in vitro antifungal activity. We show here peptide modifications in TvD1 that lead to enhanced antifungal activities. Three peptide variants, S32R, D37R, and Alpha-TvD1 (-G-M-T-R-T-) with variations in and around the β2-β3 loop region that imposes the two β-strands, β2 and β3 were generated through in vitro mutagenesis. Alpha-TvD1 exhibited enhanced antifungal activity against the fungal pathogens, Fusarium culmorum and Fusarium oxysporum with respective IC(50) values of 2.5 μM and 3.0 μM, when compared to S32R (<5.0 μM and >5.0 μM), D37R (5.5 μM and 4.5 μM), and the wild type TvD1 (6.5 μM). Because of the enhanced antifungal activity, this variant peptide was characterized further. Growth of F. culmorum in the presence of Alpha-TvD1 showed deformities in hyphal walls and nuclear damage. With respect to the plant pathogenic bacterium, Pseudomonas syringae pv. tomato strain DC3000, both Alpha-TvD1 and the wild type TvD1 showed comparable antibacterial activity. Both wild type TvD1 and Alpha-TvD1 displayed inhibitory activity against the α-amylase of the mealworm beetle, Tenebrio molitor (TMA) with the latter showing enhanced activity. The human salivary as well as barley α-amylase activities were not inhibited even at concentrations of up to 50 μM, which has been predicted to be due to differences in the pocket size and the size of the interacting loops. Present study shows that the variant Alpha-TvD1 exhibits enhanced antifungal as well as insect α-amylase inhibitory activity.
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Affiliation(s)
- S Vijayan
- Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, India
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25
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Zhou YS, Lamrani M, Chan-Park MB, Leong SSJ, Chang MW, Chen WN. iTRAQ-coupled two-dimensional liquid chromatography/tandem mass spectrometric analysis of protein profile in Escherichia coli incubated with human neutrophil peptide 1--potential in antimicrobial strategy. Rapid Commun Mass Spectrom 2010; 24:2787-2790. [PMID: 20814987 DOI: 10.1002/rcm.4712] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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26
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Smith JG, Silvestry M, Lindert S, Lu W, Nemerow GR, Stewart PL. Insight into the mechanisms of adenovirus capsid disassembly from studies of defensin neutralization. PLoS Pathog 2010; 6:e1000959. [PMID: 20585634 PMCID: PMC2891831 DOI: 10.1371/journal.ppat.1000959] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 05/20/2010] [Indexed: 12/23/2022] Open
Abstract
Defensins are effectors of the innate immune response with potent antibacterial activity. Their role in antiviral immunity, particularly for non-enveloped viruses, is poorly understood. We recently found that human alpha-defensins inhibit human adenovirus (HAdV) by preventing virus uncoating and release of the endosomalytic protein VI during cell entry. Consequently, AdV remains trapped in the endosomal/lysosomal pathway rather than trafficking to the nucleus. To gain insight into the mechanism of defensin-mediated neutralization, we analyzed the specificity of the AdV-defensin interaction. Sensitivity to alpha-defensin neutralization is a common feature of HAdV species A, B1, B2, C, and E, whereas species D and F are resistant. Thousands of defensin molecules bind with low micromolar affinity to a sensitive serotype, but only a low level of binding is observed to resistant serotypes. Neutralization is dependent upon a correctly folded defensin molecule, suggesting that specific molecular interactions occur with the virion. CryoEM structural studies and protein sequence analysis led to a hypothesis that neutralization determinants are located in a region spanning the fiber and penton base proteins. This model was supported by infectivity studies using virus chimeras comprised of capsid proteins from sensitive and resistant serotypes. These findings suggest a mechanism in which defensin binding to critical sites on the AdV capsid prevents vertex removal and thereby blocks subsequent steps in uncoating that are required for release of protein VI and endosomalysis during infection. In addition to informing the mechanism of defensin-mediated neutralization of a non-enveloped virus, these studies provide insight into the mechanism of AdV uncoating and suggest new strategies to disrupt this process and inhibit infection.
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Affiliation(s)
- Jason G. Smith
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Mariena Silvestry
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Steffen Lindert
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Wuyuan Lu
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Glen R. Nemerow
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Phoebe L. Stewart
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- * E-mail:
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27
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Froy O, Chapnik N, Nussinovitch A. Defensin carriers for better mucosal immunity in the digestive system. Int J Pharm 2010; 393:263-7. [PMID: 20438821 DOI: 10.1016/j.ijpharm.2010.04.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 04/19/2010] [Accepted: 04/25/2010] [Indexed: 11/16/2022]
Abstract
The innate immunity utilizes a battery of broad-spectrum antibacterial cationic polypeptides named defensins. In humans, defensins are the first line of defense against pathogens, and their expression has been implicated in several diseases. In addition to exerting direct antimicrobial effects, defensins facilitate and amplify innate and adaptive immune responses. HD-5 is a polypeptide that plays a pivotal role in combating bacteria in the digestive system. Our results show that HD-5 can be entrapped within alginate carriers and strengthen their structure without changing their brittleness. In addition, carrier-entrapped HD-5 is released when incubated in buffer and/or stomach-simulating solution and still retains its activity after the release. This incubation also led to a decrease in carrier strength as well as an increase in their brittleness. Nevertheless the carriers did not disintegrate and remained intact throughout the diffusion process. The release of the defensin exhibited a bimodal behavior, suggesting that it was found both in a cross-linked and non-cross-linked form within the carrier. These results indicate that defensins encapsulated within alginate carriers could possibly be used for better mucosal immunity in the digestive system.
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Affiliation(s)
- Oren Froy
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel.
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Abstract
Alpha-defensins are released from granules of leukocytes and are implicated in inflammatory and fibrotic lung diseases. In the present study, the effects of alpha-defensins on the proliferation and collagen synthesis of lung fibroblasts were examined. We found that alpha-defensin-1 and alpha-defensin-2 induced dose-dependent increases in the incorporation of 5-bromo-2'-deoxy-uridine into newly synthesized DNA in two lines of human lung fibroblasts (HFL-1 and LL-86), suggesting that alpha-defensin-1 and alpha-defensin-2 stimulate the proliferation of lung fibroblasts. alpha-defensin-1 and alpha-defensin-2 also increased collagen-I mRNA (COL1A1) levels and protein contents of collagen-I and active/dephosphorylated beta-catenin without changes in total beta-catenin protein content in lung fibroblasts (HFL-1 and LL-86). Inhibition of the beta-catenin signaling pathway using quercetin prevented increases in cell proliferation and the protein content of collagen-I and active/dephosphorylated beta-catenin in lung fibroblasts, and in COL1A1 mRNA levels and collagen release into culture medium induced by alpha-defensin-1 and alpha-defensin-2. Knocking-down beta-catenin using small interfering RNA technology also prevented alpha-defensin-induced increases in cell proliferation and the protein content of collagen-I and active/dephosphorylated beta-catenin in lung fibroblasts, and in COL1A1 mRNA levels. Moreover, increases in the phosphorylation of glycogen synthase kinase 3beta, accumulation/activation of beta-catenin, and collagen synthesis induced by alpha-defensin-1 and alpha-defensin-2 were prevented by p38 mitogen-activated protein kinase inhibitor SB203580 and phosphoinositide 3-kinase inhibitor LY294002. These results indicate that alpha-defensin-1 and alpha-defensin-2 stimulate proliferation and collagen synthesis of lung fibroblasts. The beta-catenin signaling pathway mediates alpha-defensin-induced increases in cell proliferation and collagen synthesis of lung fibroblasts. alpha-defensin-induced activation of beta-catenin in lung fibroblasts might be caused by phosphorylation/inactivation of glycogen synthase kinase 3beta as a result of the activation of the p38 mitogen-activated protein kinase and phosphoinositide 3-kinase/Akt pathways.
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Affiliation(s)
- Weihong Han
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA 30912, USA
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29
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Rodríguez-García M, Oliva H, Climent N, Escribese MM, García F, Moran TM, Gatell JM, Gallart T. Impact of alpha-defensins1-3 on the maturation and differentiation of human monocyte-derived DCs. Concentration-dependent opposite dual effects. Clin Immunol 2009; 131:374-84. [PMID: 19237318 DOI: 10.1016/j.clim.2009.01.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 01/12/2009] [Accepted: 01/14/2009] [Indexed: 12/14/2022]
Abstract
alpha-defensins1-3 are potent antimicrobial molecules that also link innate and adaptive immunity, depending on the concentration range. However, their effects on the biology of human DCs remain largely unknown. We analyzed the impact of different concentrations of alpha-defensins1-3 on the maturation and differentiation of monocyte-derived DCs (MDDCs). Low doses of alpha-defensins1-3 up-regulated CD83, CD86 and HLA-DR expression, increased TNF-alpha, IL-1beta, IL-12p40, IL-10 and IL-8 secretion, and slightly augmented allostimulatory capacity. By contrast, high doses down-regulated CD86 and HLA-DR expression, TNF-alpha, IL-1beta, IL-12p40 and IL-10 secretion and allostimulatory capacity, whereas strongly up-regulated IL-8. Furthermore, during the MDDC differentiation process, high doses of alpha-defensins1-3 affected CD14, CD11c and CD86 expression and strongly up-regulated IL-8. Results suggest that alpha-defensins1-3 might modulate the maturation and differentiation of MDDCs in vivo and therefore could be of special interest in the field of vaccine development.
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Affiliation(s)
- Marta Rodríguez-García
- Service of Immunology, Hospital Clínic Universitari de Barcelona, School of Medicine, University of Barcelona, Barcelona, Spain
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30
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Vasudevan S, Yuan J, Osapay G, Tran P, Tai K, Liang W, Kumar V, Selsted ME, Cocco MJ. Synthesis, structure, and activities of an oral mucosal alpha-defensin from rhesus macaque. J Biol Chem 2008; 283:35869-77. [PMID: 18930922 PMCID: PMC2602889 DOI: 10.1074/jbc.m806915200] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 10/10/2008] [Indexed: 11/06/2022] Open
Abstract
The oral cavity is an environment challenged by a large variety of pathogens. Consequently, the antimicrobial peptides expressed in that environment are interesting as they evolved to defend against a broad spectrum of bacteria and fungi. Here we report the discovery of new alpha-defensins from rhesus macaque oral mucosa and determine the first alpha-defensin structure from that species. The new peptides were identified by sequencing of reverse transcriptase-PCR products obtained from oral mucosal tissues, disclosing three mucosal alpha-defensins, termed rhesus macaque oral alpha-defensins (ROADs). The peptide corresponding to fully processed ROAD-1 was synthesized, subjected to folding/oxidation conditions, and purified. ROAD-1 was active against Staphylococcus aureus, Escherichia coli, and Candida albicans in a concentration-dependent manner. We determined the structure of ROAD-1 using NMR spectroscopy and find that the synthetic peptide adopts the canonical disulfide pairing and alpha-defensin fold. The antimicrobial mechanism of defensins has been correlated with their ability to disrupt and permeabilize the cell envelope, activities that depend on the surface features of the folded peptide. Although ROAD-1 maintains the defensin fold, the oral defensin displays distinct surface features when compared with other alpha-defensin structures.
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Affiliation(s)
- Sheeja Vasudevan
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697, USA
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Syeda F, Liu HY, Tullis E, Liu M, Slutsky AS, Zhang H. Differential signaling mechanisms of HNP-induced IL-8 production in human lung epithelial cells and monocytes. J Cell Physiol 2008; 214:820-7. [PMID: 17786963 PMCID: PMC4896810 DOI: 10.1002/jcp.21279] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Human neutrophil peptides (HNP) kill microorganisms but also modulate immune responses through upregulation of the chemokine IL-8 by activation of the nucleotide P2Y(6) receptor. However, the intracellular signaling mechanisms remain yet to be determined. Human lung epithelial cells (A549) and monocytes (U937) were stimulated with HNP in the absence and presence of the specific kinase inhibitors for Src, extracellular signal-regulated kinase-1 and -2 (ERK1/2), p38 mitogen-activated protein kinase (MAPK), c-Jun-N-terminal kinases (JNK), and Akt. HNP induced a rapid phosphorylation of the kinases in both cell types associated with a dose-dependent, selective production of IL-8 among 10 cytokines assayed. The HNP-induced IL-8 production was blocked by the Src tyrosine kinase inhibitor PP2, MEK1/2 inhibitor U0126, and the phosphatidylinositol 3 kinase (PI3K) inhibitor LY294002, but not by the JNK inhibitor SP600125 in both cell types. Treatment with the p38 inhibitor SB203580 attenuated the HNP-induced IL-8 production only in monocytes. Blockade of Src kinase blunted HNP-induced phosphorylation of the ERK1/2 and Akt but not p38 in monocytes. In contrast, Src inhibition had no effect on phosphorylation of the other kinases in the lung epithelial cells. We conclude that the activation of ERK1/2 and PI3K/Akt pathways is required for HNP-induced IL-8 release which occurs in a Src-independent manner in lung epithelial cells, while is Src-dependent in monocytes.
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Affiliation(s)
- Farisa Syeda
- The Keenan Research Centre, Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, ON, Canada
- Department of Anaesthesia, University of Toronto, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
- Division of Respirology, University of Toronto, Toronto, ON, Canada
| | - Hui-Yu Liu
- The Keenan Research Centre, Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, ON, Canada
- Department of Anaesthesia, University of Toronto, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
- Division of Respirology, University of Toronto, Toronto, ON, Canada
| | - Elizabeth Tullis
- The Keenan Research Centre, Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, ON, Canada
- Division of Respirology, University of Toronto, Toronto, ON, Canada
| | - Mingyao Liu
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Division of Respirology, University of Toronto, Toronto, ON, Canada
- Division of Thoracic Surgery, University of Toronto, Toronto, ON, Canada
| | - Arthur S. Slutsky
- The Keenan Research Centre, Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, ON, Canada
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
- Division of Respirology, University of Toronto, Toronto, ON, Canada
| | - Haibo Zhang
- The Keenan Research Centre, Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, ON, Canada
- Department of Anaesthesia, University of Toronto, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
- Division of Respirology, University of Toronto, Toronto, ON, Canada
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Falco A, Brocal I, Pérez L, Coll JM, Estepa A, Tafalla C. In vivo modulation of the rainbow trout (Oncorhynchus mykiss) immune response by the human alpha defensin 1, HNP1. Fish Shellfish Immunol 2008; 24:102-112. [PMID: 18023592 DOI: 10.1016/j.fsi.2007.09.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 09/24/2007] [Accepted: 09/26/2007] [Indexed: 05/25/2023]
Abstract
Recent studies have demonstrated that the synthetic human defensin-alpha1, also designated as human neutrophil peptide 1 (HNP1), not only has in vitro antiviral activity against viral hemorrhagic septicemia virus (VHSV), a fish rhabdovirus, but can also modulate some immune activities of rainbow trout (Oncorhynchus mykiss) head kidney leucocytes. However, none of these HNP1 properties have been analysed in vivo so far. Thus, in the current work, we have studied the in vivo immunomodulatory capacity of HNP1 on the rainbow trout immune system as a first approach to evaluate the possible use of this family of antimicrobial peptides (AMPs) to increase fish resistance by enhancing non-specific defence mechanisms. The intramuscular injection of synthetic HNP1 induced the transcript expression of genes encoding both pro-inflammatory cytokines (IL-1beta, TNF-alpha1 and specially IL-8) and CC chemokines (CK5B, CK6 and CK7A) as well as of the genes related to type I interferon (IFN) production (Mx1, Mx2, Mx3 and IFN regulatory factor 3, IRF-3) in different trout tissues (muscle, head kidney and blood). Furthermore, the chemotactic capacity of HNP1 towards trout leucocytes has been clearly revealed. All together, these results demonstrate that in vivo HNP1 is active across species and can modulate fish immune responses. Therefore, in a moment when most pathogens have developed resistance to commonly used antibiotics, natural antimicrobial peptides with inter-specific activity, such as HNP1, might prove to be useful model molecules for the development of novel therapeutic agents that exhibit both microbicidal and immunoenhancing capabilities.
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Affiliation(s)
- A Falco
- IBMC, Universidad Miguel Hernández, Elche, Alicante, Spain
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Andrianov IN, Nozdrachev AD, Ryzhova IV. [Comparative analysis of the effect of endogenous antibiotic defensin NP-1 and aminoglycoside antibiotic gentamicin on synaptic transmission in receptors of the frog vestibular apparatus]. Izv Akad Nauk Ser Biol 2007:705-710. [PMID: 19768964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The effect of human and rabbit neutrophilic defensins NP-1 and amonoglycoside antibiotic gentamicin on the synaptic transmission in the afferent synapse of isolated vestibular apparatus of the frog has been comparatively studied. Both defensins proved active in the concentration range of 0.0001 to 1 nM and efficiently decreased the impulse frequency in the afferent nerve fibers in a concentration-dependent manner. No significant differences in the efficiency of rabbit and human defensin NP-1 have been revealed in these experiments. Gentamicin also had an inhibitory effect on the afferent discharge in the concentration range of 10-500 microM (0.5-25 mg/kg). The inhibitory effect of gentamicin on the impulse activity of the vestibular nerve was observed at therapeutic doses. The excitatory effect of the putative neurotransmitter L-glutamate was considerably inhibited by defensin NP-1. These findings suggest that the mechanism of defensin action involves a modification of the synaptic transmission the hair receptor and is mediated by L-glutamate.
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Kougias P, Chai H, Lin PH, Yao Q, Lumsden AB, Chen C. Neutrophil antimicrobial peptide alpha-defensin causes endothelial dysfunction in porcine coronary arteries. J Vasc Surg 2007; 43:357-63. [PMID: 16476615 DOI: 10.1016/j.jvs.2005.10.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2005] [Accepted: 10/10/2005] [Indexed: 01/04/2023]
Abstract
BACKGROUND Defensins are cysteine-rich cationic polypeptides released from neutrophils that exhibit powerful antimicrobial activities. Because inflammation, including neutrophil infiltration and release of defensins, may play an important role in atherosclerosis and other vascular diseases, we determined whether alpha-defensin could cause endothelial dysfunction, a major initial event of atherosclerosis, in porcine coronary arteries. METHODS Porcine coronary arteries were sliced into 5-mm rings and treated with different concentrations of human recombinant alpha-defensin for 24 hours. Vasomotor reactivity was studied by using a myograph system. Levels of superoxide anion were detected by the lucigenin-enhanced chemiluminescence method. Endothelial nitric oxide synthase (eNOS) messenger RNA (mRNA) and protein levels were determined by real-time polymerase chain reaction and immunohistochemistry analysis, respectively. RESULTS Endothelium-dependent relaxation in response to bradykinin was significantly reduced by 40% for the rings treated with 1500 nM of alpha-defensin compared with controls (P< .05). Vessel contractility in response to the thromboxane A2 analogue U46619 and endothelium-independent relaxation in response to sodium nitroprusside were not affected with defensin treatment. In addition, the superoxide anion level at the endothelial layer of porcine coronary artery rings was significantly increased by 80% in the defensin-treated (1500 nM) vessels compared with controls (P< .05). Furthermore, the eNOS mRNA levels in endothelial cells isolated from the cultured rings treated with defensin (1500 nM) were significantly decreased by 27% compared with controls (P< .05). Immunoreactivity of eNOS in the defensin-treated vessel rings was also substantially reduced. CONCLUSIONS Defensin reduces the endothelium-dependent vasorelaxation. This effect is associated with increased superoxide radical production and decreased eNOS expression in porcine coronary arteries. CLINICAL RELEVANCE Inflammation is an important mechanism of atherosclerosis and other vascular diseases. The roles and interactions of biomediators released from inflammatory cells are not fully understood, however. This study provides new information about effects and potential molecular mechanisms of a major neutrophil releasing factor, alpha-defensin, on endothelial dysfunction of porcine coronary arteries. Thus, targeting alpha-defensin and its associated molecular mechanisms may become a new strategy to prevent vascular diseases.
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Affiliation(s)
- Panagiotis Kougias
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX 77030, USA
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Salvatore M, Garcia-Sastre A, Ruchala P, Lehrer RI, Chang T, Klotman ME. alpha-Defensin inhibits influenza virus replication by cell-mediated mechanism(s). J Infect Dis 2007; 196:835-43. [PMID: 17703413 DOI: 10.1086/521027] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Accepted: 04/17/2007] [Indexed: 11/03/2022] Open
Abstract
The innate immune system mounts the first host response to pathogens. Because alpha-defensins, which are cationic antimicrobial peptides of polymorphonuclear neutrophils and other leukocytes, are important effectors of the innate immune system, we studied the antiviral activity of human alpha-defensin-1 (also known as "human neutrophil peptide-1" [HNP-1]) against influenza virus in vitro. Treatment of cell cultures with HNP-1 soon after infection resulted in marked inhibition of influenza virus replication and viral protein synthesis. This effect was not due to cytotoxicity or to a direct effect on the virus. Treatment of cells with HNP-1 followed by its removal before infection also inhibited viral replication, suggesting that the inhibition was due to the modulation of cellular pathways. HNP-1 treatment inhibited protein kinase C (PKC) activation in infected cells, suggesting the involvement of the PKC pathway. Our data expand the previously known activity of alpha -defensins against influenza virus. Characterizing the mechanism of action of alpha -defensins may lead to the identification of new strategies for prevention and therapy.
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Affiliation(s)
- Mirella Salvatore
- Division of Infectious Diseases, Mount Sinai School of Medicine, New York, NY 100129, USA.
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Tecle T, White MR, Gantz D, Crouch EC, Hartshorn KL. Human neutrophil defensins increase neutrophil uptake of influenza A virus and bacteria and modify virus-induced respiratory burst responses. J Immunol 2007; 178:8046-52. [PMID: 17548642 DOI: 10.4049/jimmunol.178.12.8046] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Human neutrophil peptides (HNPs) are released from granules of neutrophils in response to various activating stimuli and they participate in the killing of bacteria and the stimulation of various inflammatory responses. HNPs also inhibit infectivity of enveloped viruses, including influenza A virus (IAV). In this study, we demonstrate that HNPs increase the uptake of IAV and bacteria by neutrophils. The dimeric HNPs also induced aggregation of IAV and bacterial particles, which may, in part, explain their ability to increase uptake. HNPs did not increase neutrophil respiratory burst responses to IAV. We have recently demonstrated direct interactions of HNPs with surfactant protein D (SP-D), another important effector of innate immunity and antimicrobial host defense. Although HNPs did not alter SP-D-dependent uptake of IAV, they counteracted the ability of SP-D to increase IAV-induced neutrophil H2O2 generation. Our studies reveal previously unappreciated functional effects of HNPs, expand our understanding of the antiviral properties of HNPs, and suggest important interactions between collectins and HNPs in the host response to viruses and bacteria.
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Affiliation(s)
- Tesfaldet Tecle
- Department of Medicine, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, USA
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Aarbiou J, Tjabringa GS, Verhoosel RM, Ninaber DK, White SR, Peltenburg LTC, Rabe KF, Hiemstra PS. Mechanisms of cell death induced by the neutrophil antimicrobial peptides alpha-defensins and LL-37. Inflamm Res 2007; 55:119-27. [PMID: 16673155 DOI: 10.1007/s00011-005-0062-9] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVE The aim of this study was to investigate the mechanisms of cell death mediated by the antimicrobial peptides neutrophil defensins (human neutrophil peptides 1-3 [HNP1-3]) and LL-37. MATERIALS AND METHODS HNP1-3- and LL-37-mediated cell death was assessed in human lung epithelial cells and Jurkat T-cells in serum-free culture media. RESULTS Both HNP1-3 and LL-37 induced cell death in Jurkat T-cells and A549 cells. HNP1-3 but not LL-37 induced caspase-3/-7 activity and caused cleavage of [ADP-ribose] polymerase (PARP) in Jurkat cells, while in A549 cells neither peptides induced caspase-3/-7 activation. Furthermore, both peptides increased mitochondrial cytochrome c release in A549 and Jurkat cells. Our observation that over-expression of the anti-apoptotic protein Bcl-2 in Jurkat cells did not affect HNP1-3- or LL-37-induced cell death indicates that antimicrobial peptide-induced cytochrome c release is not involved in peptide-induced cell death. Finally, in A549 cells and in primary bronchial epithelial cells, both HNP1-3 and LL-37 induced DNA breaks as demonstrated by increased TUNEL labelling. CONCLUSIONS The results from this study suggest that the antimicrobial peptides HNP1-3 and LL-37 induce cell death, which is associated with mitochondrial injury and mediated via different intracellular pathways.
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Affiliation(s)
- J Aarbiou
- Department of Pulmonology, C3-P, Leiden University Medical Center, P.O. Box 9600, 2300, RC Leiden, The Netherlands
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Falco A, Mas V, Tafalla C, Perez L, Coll JM, Estepa A. Dual antiviral activity of human alpha-defensin-1 against viral haemorrhagic septicaemia rhabdovirus (VHSV): inactivation of virus particles and induction of a type I interferon-related response. Antiviral Res 2007; 76:111-23. [PMID: 17655941 DOI: 10.1016/j.antiviral.2007.06.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Revised: 06/11/2007] [Accepted: 06/12/2007] [Indexed: 12/22/2022]
Abstract
It is well known that human alpha-defensin-1, also designated as human neutrophil peptide 1 (HNP1), is a potent inhibitor towards several enveloped virus infecting mammals. In this report, we analyzed the mechanism of the antiviral action of this antimicrobial peptide (AMP) on viral haemorrhagic septicaemia virus (VHSV), a salmonid rhabdovirus. Against VHSV, synthetic HNP1 possesses two antiviral activities. The inactivation of VHSV particles probably through interfering with VHSV-G protein-dependent fusion and the inhibition of VHSV replication in target cells by up-regulating genes related to the type I interferon (IFN) response, such as Mx. Neither induction of IFN-stimulated genes (ISGs) by HNP1 nor their antiviral activity against fish rhabovirus has been previously reported. Therefore, we can conclude that besides to acting as direct effector, HNP1 acts across species and can elicit one of the strongest antiviral responses mediated by innate immune system. Since the application of vaccine-based immunization strategies is very limited, the used of chemicals is restricted because of their potential harmful impact on the environment and no antimicrobial peptides from fish that exhibit both antiviral and immunoenhancing capabilities have been described so far, HNP1 could be a model molecule for the development of antiviral agents for fish. In addition, these results further confirm that molecules that mediate the innate resistance of animals to virus may prove useful as templates for new antivirals in both human and animal health.
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Affiliation(s)
- A Falco
- IBMC, Miguel Hernández University, 03202 Elche, Spain
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Cummings JE, Vanderlick TK. Aggregation and hemi-fusion of anionic vesicles induced by the antimicrobial peptide cryptdin-4. Biochimica et Biophysica Acta (BBA) - Biomembranes 2007; 1768:1796-804. [PMID: 17531950 DOI: 10.1016/j.bbamem.2007.04.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 04/20/2007] [Accepted: 04/20/2007] [Indexed: 10/23/2022]
Abstract
We show that cryptdin-4 (Crp4), an antimicrobial peptide found in mice, induces the aggregation and hemi-fusion of charged phospholipid vesicles constructed of the anionic lipid POPG and the zwitterionic lipid POPC. Hemi-fusion is confirmed with positive total lipid-mixing assay results, negative inner monolayer lipid-mixing assay results, and negative results from contents-mixing assays. Aggregation, as quantified by absorbance and dynamic light scattering, is self-limiting, creating finite-sized vesicle assemblies. The rate limiting step in the formation process is the mixing of juxtaposed membrane leaflets, which is regulated by bound peptide concentration as well as vesicle radius (with larger vesicles less prone to hemi-fusion). Bound peptide concentration is readily controlled by total peptide concentration and the fraction of anionic lipid in the vesicles. As little as 1% PEGylated lipid significantly reduces aggregate size by providing a steric barrier for membrane apposition. Finally, as stable hemi-fusion is a rare occurrence, we compare properties of Crp4 to those of many peptides known to induce complete fusion and lend insight into conditions necessary for this unusual type of membrane merger.
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Affiliation(s)
- Jason E Cummings
- Department of Chemical Engineering, Princeton University, Princeton, NJ 08544, USA
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Lundy FT, Nelson J, Lockhart D, Greer B, Harriott P, Marley JJ. Antimicrobial activity of truncated alpha-defensin (human neutrophil peptide (HNP)-1) analogues without disulphide bridges. Mol Immunol 2007; 45:190-3. [PMID: 17548109 DOI: 10.1016/j.molimm.2007.04.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2007] [Accepted: 04/16/2007] [Indexed: 12/21/2022]
Abstract
Antimicrobial peptides play an important role in host defence, particularly in the oral cavity where there is constant challenge by microorganisms. The alpha-defensin antimicrobial peptides comprise 30-50% of the total protein in the azurophilic granules of human neutrophils, the most abundant of which is human neutrophil peptide 1 (HNP-1). Despite its antimicrobial activity, a limiting factor in the potential therapeutic use of HNP-1 is its chemical synthesis with the correct disulphide topology. In the present study, we synthesised a range of truncated defensin analogues lacking disulphide bridges. All the analogues were modelled on the C-terminal region of HNP-1 and their antimicrobial activity was tested against a range of microorganisms, including oral pathogens. Although there was variability in the antimicrobial activity of the truncated analogues synthesised, a truncated peptide named 2Abz(23)S(29) displayed a broad spectrum of antibacterial activity, effectively killing all the bacterial strains tested. The finding that truncated peptides, modelled on the C-terminal beta-hairpin region of HNP-1 but lacking disulphide bridges, display antimicrobial activity could aid their potential use in therapeutic interventions.
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Affiliation(s)
- Fionnuala T Lundy
- Oral Science Research Centre, School of Medicine and Dentistry, Queen's University Belfast, Belfast BT12 6BP, Northern Ireland, UK.
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Furci L, Sironi F, Tolazzi M, Vassena L, Lusso P. Alpha-defensins block the early steps of HIV-1 infection: interference with the binding of gp120 to CD4. Blood 2007; 109:2928-35. [PMID: 17132727 DOI: 10.1182/blood-2006-05-024489] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Alpha-defensins are antibiotic peptides that act as natural inhibitors of HIV-1 infection. However, the mechanisms of such inhibition are still unclear. Here we demonstrate that alpha-defensins block the earliest steps in the viral infectious cycle, as documented using an HIV-1 envelope-mediated cell-fusion assay. A broad-spectrum inhibitory activity was observed on primary and laboratory-adapted HIV-1 isolates irrespective of their coreceptor specificity and genetic subtype. A primary mechanism of such inhibition was identified as the ability of alpha-defensins to bind specifically both to the primary HIV-1 cellular receptor, CD4, and to the viral envelope glycoprotein, gp120. Moreover, treatment of CD4+ T cells with alpha-defensins caused a dramatic downmodulation of CD4 expression. By monoclonal antibody competition, the regions of interaction with alpha-defensins were mapped to the D1 domain of CD4 and to a surface contiguous to the CD4- and coreceptor-binding sites of gp120. Consistent with these findings, alpha-defensins inhibited the binding of gp120 to CD4. These data demonstrate that alpha-defensins specifically block the initial phase of the HIV infectious cycle and modulate the expression of CD4, a critical receptor in the physiology of T-cell activation.
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Affiliation(s)
- Lucinda Furci
- Unit of Human Virology, Department of Biological and Technological Research (DIBIT), San Raffaele Scientific Institute, Milan, Italy
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42
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Hubert P, Herman L, Maillard C, Caberg JH, Nikkels A, Pierard G, Foidart JM, Noel A, Boniver J, Delvenne P. Defensins induce the recruitment of dendritic cells in cervical human papillomavirus-associated (pre)neoplastic lesions formed in vitro and transplanted in vivo. FASEB J 2007; 21:2765-75. [PMID: 17470569 DOI: 10.1096/fj.06-7646com] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In addition to their direct antimicrobial activity, defensins might also influence adaptive immunity by attracting immature dendritic cells (DC). As these cells have been shown to be deficient in uterine cervix carcinogenesis, we evaluated the ability of alpha-defensin (HNP-2, human neutrophil defensin 2) and beta-defensin (HbetaD2, human beta defensin 2) to stimulate their migration in human papillomavirus (HPV)-associated (pre)cancers. We first observed, using RT-PCR and immunohistology, that HbetaD2 is absent in HPV-transformed keratinocytes and that it is weakly expressed in cervical (pre)neoplastic lesions in comparison with normal keratinocytes. We next demonstrated that defensins exert a chemotactic activity for DC in a Boyden Chamber assay and stimulate their infiltration in an in vitro-formed (pre)neoplastic epithelium (organotypic culture of HPV-transformed keratinocytes). To evaluate the ability of defensins also to recruit DC in vivo, we developed a model of immunodeficient mice grafted with organotypic cultures of HPV+ keratinocytes, which form an epithelium similar to a high-grade neoplastic lesion, with tumoral invasion and neovascularization. Intravenously injected human DC were able to infiltrate grafts of HPV+ keratinocytes after administration of HNP-2 in the transplantation chamber. Taken together, these results suggest that defensins could reverse a frequent immune alteration observed in cancer development.
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Affiliation(s)
- Pascale Hubert
- Department of Pathology B35, University Hospital of Liège, CHU Sart Tilman, 4000 Liège, Belgium.
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Tanabe H, Ayabe T, Maemoto A, Ishikawa C, Inaba Y, Sato R, Moriichi K, Okamoto K, Watari J, Kono T, Ashida T, Kohgo Y. Denatured human alpha-defensin attenuates the bactericidal activity and the stability against enzymatic digestion. Biochem Biophys Res Commun 2007; 358:349-55. [PMID: 17482139 DOI: 10.1016/j.bbrc.2007.04.132] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2007] [Accepted: 04/22/2007] [Indexed: 01/07/2023]
Abstract
alpha-Defensin is an antimicrobial peptide which plays an important role in innate immunity. Human defensin (HD)-5 is stored in the Paneth cells of the small intestine as a pro-form and is cleaved by trypsin, which is co-secreted from the Paneth cell granules. The mature HD-5 is protected from further digestion by the proteolysis enzyme. We generated both recombinant HD-5 and proHD-5, and the reduced form of each peptide in order to determine their physiological roles of the disulfide bonds. The reduced proHD-5 attenuated the bactericidal activity and the stability against the trypsin digestion. Human defensin was protected from the enzymatic degradation by disulfide bridges. We further purified the HD-5 with a disulfide variation in the small intestine of Crohn's disease patients. The HD-5 was sensitive to the trypsin treatment. These observations evidently predict that a defensin deficiency may be caused by a disulfide disorder in the disease.
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Affiliation(s)
- Hiroki Tanabe
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical College, Japan.
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Yoshioka S, Mukae H, Ishii H, Kakugawa T, Ishimoto H, Sakamoto N, Fujii T, Urata Y, Kondo T, Kubota H, Nagata K, Kohno S. Alpha-defensin enhances expression of HSP47 and collagen-1 in human lung fibroblasts. Life Sci 2007; 80:1839-45. [PMID: 17367817 DOI: 10.1016/j.lfs.2007.02.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Revised: 01/20/2007] [Accepted: 02/14/2007] [Indexed: 11/17/2022]
Abstract
Neutrophils and lung fibroblasts are thought to play a role in the pathogenesis of pulmonary fibrosis. We reported previously that heat shock protein 47 (HSP47), a collagen-specific molecular chaperon, and collagen-1 synthesis were involved in pulmonary fibrosis, and that plasma levels of alpha-defensins (HNP; human neutrophil peptide), cationic proteins with antimicrobial and cytotoxic activity in neutrophils, were significantly higher in patients with idiopathic pulmonary fibrosis than in control subjects. Here, we investigated the direct effect of HNP-1 in vitro on the expression of HSP47 and collagen-1 in human lung fibroblasts (NHLF). HNP-1 at 5 microg/ml induced fibroblast proliferation but at concentrations >50 microg/ml, HNP-1 reduced cell viability. Incubation of NHLF with 10 to 25 microg/ml of HNP-1 for 24-h increased the expression of HSP47 and collagen-1 mRNAs (p<0.05). The levels of HSP47 protein also increased significantly at 50 microg/ml, and those of collagen-1 protein increased at 10 to 50 microg/ml of HNP-1 (p<0.05). The mitogen-activated protein kinase (MAPK) signaling pathway in NHLF was activated by HNP-1 stimulation, but inhibitor of MEK (PD98059) did not block HNP-1-induced HSP47 protein production. Our results suggest that alpha-defensin is a fibrogenic mediator that promotes collagen synthesis through the upregulation of HSP47 and collagen-1 in lung fibroblasts and participates in the pathogenesis of neutrophil-induced pulmonary fibrosis.
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Affiliation(s)
- Sumako Yoshioka
- Second Department of Internal Medicine, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki, 852-8501 Japan
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Abstract
To understand their mechanism of antimicrobial activity against Gram-negative bacteria, ostrich beta-defensins, ostricacins-1 and 2 (Osp-1 and Osp-2), were compared with those of sheep myeloid antimicrobial peptide (SMAP)-29 and human neutrophil peptide (HNP)-1, well-characterized sheep alpha-helical and human alpha-defensin peptides, respectively. Fluorescence-based biochemical assays demonstrated that the ostricacins bound lipopolysaccharides and disrupted both outer and cytoplasmic membrane integrity. The ostricacins' permeabilizing ability was weaker than that of SMAP-29, but stronger than HNP-1. As ostricacins have previously shown the ability to inhibit bacterial growth, these peptides were suggested to be bacteriostatic to Gram-negative bacteria, which are caused by the interaction between the peptides and cytoplasmic targets causing the inhibition of DNA, RNA, and protein synthesis as well as enzymatic activities. These findings indicated promising possibilities for the peptides to be used in the development of therapeutic and topical products.
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Affiliation(s)
- Haryadi Sugiarto
- Biotechnology Group, Institute of Technology and Engineering, Massey University, Palmerston North, New Zealand
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46
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Vaschetto R, Grinstein J, Del Sorbo L, Khine AA, Voglis S, Tullis E, Slutsky AS, Zhang H. Role of human neutrophil peptides in the initial interaction between lung epithelial cells and CD4+ lymphocytes. J Leukoc Biol 2007; 81:1022-31. [PMID: 17215524 DOI: 10.1189/jlb.0706435] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Human neutrophil peptides (HNP) exert immune-modulating effects. We hypothesized that HNP link innate and adaptive immunity through activation of costimulatory molecules. Human lung epithelial cells and CD4+ lymphocytes were treated with HNP separately or in coculture. Stimulation with HNP induced an increase in cell surface expression of CD54 (ICAM-1), CD80, and CD86 on lung epithelial cells and the corresponding major ligands, CD11a (LFA-1), CD152 (CTLA-4), and CD28 on CD4+ lymphocytes. There was an increased nuclear expression of the transcription factor p53 in human alveolar A549 cells and an elevated NF-kappaB (p50) and a degradation of I-kappaB protein in CD4+ lymphocytes following HNP stimulation. HNP enhanced the interaction between A549 cells and CD4+ lymphocytes by increasing cell adhesion and release of IFN-gamma, IL-2, and IL-8. This was attenuated by using an alpha1-proteinase inhibitor to neutralize HNP. We conclude that HNP play an important role in linking innate to acquired immunity by activation of costimulatory molecules in lung epithelial cells and CD4+ lymphocytes.
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Affiliation(s)
- Rosanna Vaschetto
- Department of Anaesthesia, University of Toronto, St. Michael's Hospital, Room 7-007, Queen Wing, 30 Bond St., Toronto, ON M5B 1W8, Canada
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de Leeuw E, Burks SR, Li X, Kao JPY, Lu W. Structure-dependent functional properties of human defensin 5. FEBS Lett 2007; 581:515-20. [PMID: 17250830 PMCID: PMC1832120 DOI: 10.1016/j.febslet.2006.12.036] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Revised: 12/06/2006] [Accepted: 12/15/2006] [Indexed: 10/23/2022]
Abstract
The mucosal epithelium secretes a variety of antimicrobial peptides that act as part of the innate immune system to protect against invading microbes. Here, we describe the functional properties of human defensin (HD) 5, the major antimicrobial peptide produced by Paneth cells in the ileum, in relation to its structure. The antimicrobial activity of HD-5 against Escherichia coli proved to be independent of its structure, whereas the unstructured peptide showed greatly reduced antimicrobial activity against Staphylococcus aureus. We find that HD-5 binds to the cell membrane of intestinal epithelial cells and induced secretion of the chemokine interleukin (IL)-8 in a concentration- and structure-dependent fashion. Incubation of HD-5 in the presence of tumor necrosis factor alpha further increased IL-8 secretion synergistically, suggesting that HD-5 may act as a regulator of the intestinal inflammatory response.
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Affiliation(s)
- Erik de Leeuw
- Institute of Human Virology, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, USA.
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48
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Liu CY, Lin HC, Yu CT, Lin SM, Lee KY, Chen HC, Chou CL, Huang CD, Chou PC, Liu WT, Wang CH, Kuo HP. The concentration-dependent chemokine release and pro-apoptotic effects of neutrophil-derived α-defensin-1 on human bronchial and alveolar epithelial cells. Life Sci 2007; 80:749-58. [PMID: 17141275 DOI: 10.1016/j.lfs.2006.11.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Revised: 10/25/2006] [Accepted: 11/02/2006] [Indexed: 11/18/2022]
Abstract
Defensins play a pivotal role in antimicrobial reactions, inflammatory responses, wound repair, and specific immunity. In inflammatory and infectious lung diseases, alpha-defensins are released from recruited neutrophils, and modulate a variety of lung cell functions. We found that human bronchial and alveolar epithelial cells treated with low and moderate concentrations (5 and 10 micro g/ml) of purified neutrophil-derived alpha-defensin-1 secreted more interleukin (IL)-8 and monocyte chemoattractant protein (MCP)-1 in a dose- and time-dependent manner. Under moderate and high concentrations (10 and 20 micro g/ml) of alpha-defensin-1, we observed typical apoptotic changes in the lung epithelial cells after stimulation for 24 h. Furthermore, alpha-defensin-1 triggered lung cell detachment in a time- and dose-dependent manner at moderate and high concentrations. Prior to the detachment, caspase-3 activity significantly increased. On confocal laser microscopy, rapid translocation of alpha-defensin-1 to the endoplasmic reticulum (ER) was noted. These findings suggest that neutrophil-derived alpha-defensin-1 has pro-inflammatory and apoptotic effects in human bronchial and alveolar epithelial cells, which are concentration-dependent and may be associated with ER activity.
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Affiliation(s)
- Chien-Ying Liu
- Department of Thoracic Medicine, Chang-Gung Memorial Hospital and Chang-Gung University, Taipei, Taiwan
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Rosengren KJ, Daly NL, Fornander LM, Jönsson LMH, Shirafuji Y, Qu X, Vogel HJ, Ouellette AJ, Craik DJ. Structural and Functional Characterization of the Conserved Salt Bridge in Mammalian Paneth Cell α-Defensins. J Biol Chem 2006; 281:28068-78. [PMID: 16857681 DOI: 10.1074/jbc.m604992200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
alpha-Defensins are mediators of mammalian innate immunity, and knowledge of their structure-function relationships is essential for understanding their mechanisms of action. We report here the NMR solution structures of the mouse Paneth cell alpha-defensin cryptdin-4 (Crp4) and a mutant (E15D)-Crp4 peptide, in which a conserved Glu(15) residue was replaced by Asp. Structural analysis of the two peptides confirms the involvement of this Glu in a conserved salt bridge that is removed in the mutant because of the shortened side chain. Despite disruption of this structural feature, the peptide variant retains a well defined native fold because of a rearrangement of side chains, which result in compensating favorable interactions. Furthermore, salt bridge-deficient Crp4 mutants were tested for bactericidal effects and resistance to proteolytic degradation, and all of the variants had similar bactericidal activities and stability to proteolysis. These findings support the conclusion that the function of the conserved salt bridge in Crp4 is not linked to bactericidal activity or proteolytic stability of the mature peptide.
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Affiliation(s)
- K Johan Rosengren
- Department of Chemistry and Biomedical Sciences, University of Kalmar, SE-391 82 Kalmar, Sweden.
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Li J, Raghunath M, Tan D, Lareu RR, Chen Z, Beuerman RW. Defensins HNP1 and HBD2 Stimulation of Wound-Associated Responses in Human Conjunctival Fibroblasts. ACTA ACUST UNITED AC 2006; 47:3811-9. [PMID: 16936092 DOI: 10.1167/iovs.05-1360] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
PURPOSE To study the responses of human conjunctival fibroblasts (HCFs) to stimulation by human neutrophil defensin 1 (HNP1) and beta defensin2 (HBD2). METHODS Defensin-stimulated gene expression in primary cultures of HCFs was analyzed by real-time PCR after exposure to various concentrations of HNP1 or HBD2. Gene and protein expression for selected collagens, matrix metalloproteinases, and tissue inhibitors of metalloproteinases were determined by real-time PCR and ELISA analysis. Activation of p42/44 mitogen-activated protein (MAP) and Akt was analyzed by Western blot. RESULTS HCFs did not express significant levels of the genes for HNP1 or HBD1-3. However, HNP1 and HBD2 stimulated HCF proliferation, the activation of p42/44 MAP kinase, and Akt kinase in a dose-dependent manner. HNP1 and HBD2 were not found to be chemotoxic for HCFs. It was demonstrated with the use of U0126 and wortmannin that the activation of p42/44 MAP kinase and Akt was responsible for the increased HCF proliferation observed under HNP1 and HBD2 stimulation. HNP1 stimulated the expression of the genes for collagen I, III, VI, and VIII. In addition, it reduced the secretion of collagen I protein but increased its intracellular retention. HNP1 and HBD2 upregulated the transcription and translation of MMP1. Small increases were observed in MMP14 gene expression after HNP1 stimulation and MMP2 gene expression after HBD2 stimulation. CONCLUSIONS The results of this study suggest that HNP1 and HBD2 have a potential role in the biosynthetic and tissue remodeling responses of conjunctival fibroblasts.
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Affiliation(s)
- Jing Li
- Singapore Eye Research Institute, Singapore
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