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Johnstone KF, Herzberg MC. Antimicrobial peptides: Defending the mucosal epithelial barrier. FRONTIERS IN ORAL HEALTH 2022; 3:958480. [PMID: 35979535 PMCID: PMC9376388 DOI: 10.3389/froh.2022.958480] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 06/30/2022] [Indexed: 11/13/2022] Open
Abstract
The recent epidemic caused by aerosolized SARS-CoV-2 virus illustrates the importance and vulnerability of the mucosal epithelial barrier against infection. Antimicrobial proteins and peptides (AMPs) are key to the epithelial barrier, providing immunity against microbes. In primitive life forms, AMPs protect the integument and the gut against pathogenic microbes. AMPs have also evolved in humans and other mammals to enhance newer, complex innate and adaptive immunity to favor the persistence of commensals over pathogenic microbes. The canonical AMPs are helictical peptides that form lethal pores in microbial membranes. In higher life forms, this type of AMP is exemplified by the defensin family of AMPs. In epithelial tissues, defensins, and calprotectin (complex of S100A8 and S100A9) have evolved to work cooperatively. The mechanisms of action differ. Unlike defensins, calprotectin sequesters essential trace metals from microbes, which inhibits growth. This review focuses on defensins and calprotectin as AMPs that appear to work cooperatively to fortify the epithelial barrier against infection. The antimicrobial spectrum is broad with overlap between the two AMPs. In mice, experimental models highlight the contribution of both AMPs to candidiasis as a fungal infection and periodontitis resulting from bacterial dysbiosis. These AMPs appear to contribute to innate immunity in humans, protecting the commensal microflora and restricting the emergence of pathobionts and pathogens. A striking example in human innate immunity is that elevated serum calprotectin protects against neonatal sepsis. Calprotectin is also remarkable because of functional differences when localized in epithelial and neutrophil cytoplasm or released into the extracellular environment. In the cytoplasm, calprotectin appears to protect against invasive pathogens. Extracellularly, calprotectin can engage pathogen-recognition receptors to activate innate immune and proinflammatory mechanisms. In inflamed epithelial and other tissue spaces, calprotectin, DNA, and histones are released from degranulated neutrophils to form insoluble antimicrobial barriers termed neutrophil extracellular traps. Hence, calprotectin and other AMPs use several strategies to provide microbial control and stimulate innate immunity.
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Affiliation(s)
| | - Mark C. Herzberg
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, United States
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Setoguchi D, Nagata E, Oho T. A novel mannose-containing sialoprotein adhesin involved in the binding of Candida albicans cells to DMBT1. Mol Oral Microbiol 2022; 37:154-163. [PMID: 35675924 DOI: 10.1111/omi.12374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 05/21/2022] [Accepted: 06/01/2022] [Indexed: 12/01/2022]
Abstract
Candida albicans colonizes the oral cavity and causes oral candidiasis and early childhood caries synergistically with cariogenic Streptococcus mutans. Colonization of oral tissues with C. albicans is an essential step in the initiation of these infectious diseases. Deleted in malignant brain tumors 1 (DMBT1), also known as salivary agglutinin or gp-340, belongs to the scavenger receptor cysteine-rich (SRCR) superfamily and has important functions in innate immunity. In the oral cavity, DMBT1 causes microbial adherence to tooth enamel and oral mucosa surfaces, but the adherence of C. albicans to DMBT1 has not been examined. In this study, we investigated the binding of C. albicans to DMBT1 and isolated the fungal components responsible for the binding. Candida albicans specifically bound to DMBT1 and strongly bound to the peptide domain SRCRP2. Binding to SRCRP2 was inhibited by N-acetylneuraminic acid and mannose and by lectins recognizing these sugars. The isolated component had a molecular mass of 25 kDa, contained sialic acid and mannose residues, and inhibited C. albicans binding to SRCRP2. The localization of the 25-kDa protein on the surface of C. albicans cell walls was confirmed by immunostaining and a cell ELISA using an antiserum to the protein, and Western blotting revealed the presence of the 25-kDa protein in the cell wall fraction of C. albicans. These results suggest that the isolated adhesin is localized on the surface of C. albicans cell walls and that sialic acid and mannose residues in the adhesin play a significant role in the binding reaction.
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Affiliation(s)
- Daisuke Setoguchi
- Department of Preventive Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Emi Nagata
- Division of Preventive Dentistry, Kagoshima University Hospital, Kagoshima, Japan
| | - Takahiko Oho
- Department of Preventive Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
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Salivary Trefoil Factor Family (TFF) Peptides and Their Roles in Oral and Esophageal Protection: Therapeutic Potential. Int J Mol Sci 2021; 22:ijms222212221. [PMID: 34830103 PMCID: PMC8624312 DOI: 10.3390/ijms222212221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/08/2021] [Accepted: 11/10/2021] [Indexed: 11/16/2022] Open
Abstract
Human saliva is a complex body fluid with more than 3000 different identified proteins. Besides rheological and lubricating properties, saliva supports wound healing and acts as an antimicrobial barrier. TFF peptides are secreted from the mucous acini of the major and minor salivary glands and are typical constituents of normal saliva; TFF3 being the predominant peptide compared with TFF1 and TFF2. Only TFF3 is easily detectable by Western blotting. It occurs in two forms, a disulfide-linked homodimer (Mr: 13k) and a high-molecular-mass heterodimer with IgG Fc binding protein (FCGBP). TFF peptides are secretory lectins known for their protective effects in mucous epithelia; the TFF3 dimer probably has wound-healing properties due to its weak motogenic effect. There are multiple indications that FCGBP and TFF3-FCGBP play a key role in the innate immune defense of mucous epithelia. In addition, homodimeric TFF3 interacts in vitro with the salivary agglutinin DMBT1gp340. Here, the protective roles of TFF peptides, FCGBP, and DMBT1gp340 in saliva are discussed. TFF peptides are also used to reduce radiotherapy- or chemotherapy-induced oral mucositis. Thus, TFF peptides, FCGBP, and DMBT1gp340 are promising candidates for better formulations of artificial saliva, particularly improving wound healing and antimicrobial effects even in the esophagus.
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Zhang S, Huo X, Li M, Hou R, Cong X, Xu X. Oral antimicrobial activity weakened in children with electronic waste lead exposure. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:14763-14770. [PMID: 32056098 DOI: 10.1007/s11356-020-08037-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 02/10/2020] [Indexed: 02/05/2023]
Abstract
Environmental lead (Pb) exposure can induce dysbacteriosis, impair oral health, and is associated with the development of dental caries. However, the mechanism is unclear. The aim of this study was to explore the effects of Pb toxicity on oral antimicrobial activity in children in an e-waste area. Results showed higher blood Pb levels in e-waste-exposed group children, accompanied by decreased saliva SAG (salivary agglutinin) concentrations, increased peripheral WBC (white blood cell) counts and monocyte counts, and elevated peripheral monocyte percentage. LnPb (natural logarithmic transformation of blood Pb level) was negatively correlated with saliva SAG concentration, while positively correlated with peripheral monocyte percentage. Saliva SAG concentration played a complete mediating role in the correlation of LnPb to peripheral monocyte percentage. To our knowledge, this is the first study on the relationship of environmental Pb exposure and oral antimicrobial activity in children, showing that environmental Pb exposure may weaken oral antimicrobial activity through reducing saliva SAG concentration, which may raise the risk of oral dysbacteriosis and ultimately pathogen infection.
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Affiliation(s)
- Shaocheng Zhang
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, 22 Xinling Rd, Shantou, 515041, Guangdong, China
| | - Xia Huo
- Laboratory of Environmental Medicine and Developmental Toxicology, Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 511486, Guangdong, China
| | - Minghui Li
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, 22 Xinling Rd, Shantou, 515041, Guangdong, China
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, 9713 GZ, Groningen, The Netherlands
| | - Ruikun Hou
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, 22 Xinling Rd, Shantou, 515041, Guangdong, China
| | - Xiaowei Cong
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, 22 Xinling Rd, Shantou, 515041, Guangdong, China
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, 9713 GZ, Groningen, The Netherlands
| | - Xijin Xu
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, 22 Xinling Rd, Shantou, 515041, Guangdong, China.
- Department of Cell Biology and Genetics, Shantou University Medical College, Shantou, 515041, Guangdong, China.
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Zhang S, Huo X, Zhang Y, Lu X, Xu C, Xu X. The association of PM 2.5 with airway innate antimicrobial activities of salivary agglutinin and surfactant protein D. CHEMOSPHERE 2019; 226:915-923. [PMID: 31509921 DOI: 10.1016/j.chemosphere.2019.04.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/04/2019] [Accepted: 04/04/2019] [Indexed: 02/05/2023]
Abstract
Fine particulate matter ≤2.5 μm (PM2.5) is a prominent global public health risk factor that can cause respiratory infection by downregulating the amounts of antimicrobial proteins and peptides (AMPs). Both salivary agglutinin (SAG) and surfactant protein D (SPD) are important AMPs in respiratory mucosal fluid, providing protection against airway pathogen invasion and infection by inducing microbial aggregation and enhancing pathogen clearance. However, the relationship between PM2.5 and these AMPs is unclear. To better understand the relationship between PM2.5 and airway innate immune defenses, we review the respiratory antimicrobial activities of SAG and SPD, as well as the adverse effects of PM2.5 on airway innate antimicrobial defense. We speculate there exists a dual effect between PM2.5 and respiratory antimicrobial activity, which means that PM2.5 suppresses respiratory antimicrobial activity through downregulating airway AMPs, while airway AMPs accelerate PM2.5 clearance by inducing PM2.5 microbial aggregation. We propose further research on the relationship between PM2.5 and these AMPs.
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Affiliation(s)
- Shaocheng Zhang
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, Shantou, 515041, Guangdong, China
| | - Xia Huo
- Laboratory of Environmental Medicine and Developmental Toxicology, Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 511486, Guangdong, China
| | - Yuling Zhang
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, Shantou, 515041, Guangdong, China
| | - Xueling Lu
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, Shantou, 515041, Guangdong, China
| | - Cheng Xu
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, Shantou, 515041, Guangdong, China
| | - Xijin Xu
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, Shantou, 515041, Guangdong, China; Department of Cell Biology and Genetics, Shantou University Medical College, Shantou, 515041, Guangdong, China.
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Zhang S, Huo X, Zhang Y, Huang Y, Zheng X, Xu X. Ambient fine particulate matter inhibits innate airway antimicrobial activity in preschool children in e-waste areas. ENVIRONMENT INTERNATIONAL 2019; 123:535-542. [PMID: 30622078 DOI: 10.1016/j.envint.2018.12.061] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 12/12/2018] [Accepted: 12/28/2018] [Indexed: 02/05/2023]
Abstract
Ambient fine particulate matter (PM2.5) is a risk factor for respiratory diseases. Previous studies suggest that PM2.5 exposure may down-regulate airway antimicrobial proteins and peptides (AMPs), thereby accelerating airway pathogen infection. However, epidemiological research is scarce. Hence, we estimated the associations between individual PM2.5 chronic daily intake (CDI) and the levels of the airway AMP salivary agglutinin (SAG), as well as peripheral leukocyte counts and pro-inflammatory cytokines, of preschool children in Guiyu (an e-waste area) and Haojiang (a reference area located 31.6 km to the east of Guiyu). We recruited 581 preschool children from Guiyu and Haojiang, of which 222 were included in this study for a matching design (Guiyu: n = 110 vs. Haojiang: n = 112). Air PM2.5 pollution data was collected to calculate individual PM2.5 CDI. The mean concentration of PM2.5 in Guiyu was higher than in Haojiang, resulting in a higher individual PM2.5 CDI. Concomitantly, saliva SAG levels were lower in Guiyu children (5.05 ng/mL) than in Haojiang children (8.68 ng/mL), and were negatively correlated with CDI. Additionally, peripheral counts of white blood cells, and the concentrations of interleukin-8 and tumor necrosis factor-alpha, in Guiyu children were greater than in Haojiang children, and were positively associated with CDI. Similar results were found for neutrophils and monocytes. To our knowledge, this is the first study on the relationship between PM2.5 exposure and innate airway antimicrobial activity in children, in an e-waste area, showing that PM2.5 pollution may weaken airway antimicrobial activity by down-regulation of saliva SAG levels, which might accelerate airway pathogen infection in children.
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Affiliation(s)
- Shaocheng Zhang
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, Shantou 515041, Guangdong, China
| | - Xia Huo
- Laboratory of Environmental Medicine and Developmental Toxicology, Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511486, Guangdong, China
| | - Yu Zhang
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, Shantou 515041, Guangdong, China; Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen 9713, GZ, the Netherlands
| | - Yu Huang
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, Shantou 515041, Guangdong, China
| | - Xiangbin Zheng
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, Shantou 515041, Guangdong, China
| | - Xijin Xu
- Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, Shantou 515041, Guangdong, China; Department of Cell Biology and Genetics, Shantou University Medical College, Shantou 515041, Guangdong, China.
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Tuttolomondo M, Hansen PL, Mollenhauer J, Ditzel HJ. One-step FPLC-size-exclusion chromatography procedure for purification of rDMBT1 6 kb with increased biological activity. Anal Biochem 2017; 542:16-19. [PMID: 29169777 DOI: 10.1016/j.ab.2017.11.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 11/16/2017] [Accepted: 11/19/2017] [Indexed: 10/18/2022]
Abstract
Deleted in Malignant Brain Tumor 1 (DMBT1, alias SAG or gp340) is a pattern recognition receptor involved in immune defense, cell polarization, differentiation and regeneration. To investigate the role of the protein in physiological and pathological processes, the protein has often been isolated from saliva or produced in vitro and purified by a multistep affinity purification procedure using bacteria, followed by FPLC. Here, we compared a simple, one-step FPLC-SEC protocol for purification of recombinant DMBT1 6 kb, with that of the standard bacteria affinity purification-based protocol. Our data suggest that our FPLC-SEC protocol yields DMBT1 in a more native conformation.
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Affiliation(s)
- Martina Tuttolomondo
- Lundbeckfonden Center of Excellence NanoCAN, University of Southern Denmark, Odense, Denmark; Department of Cancer and Inflammation Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.
| | - Pernille Lund Hansen
- Lundbeckfonden Center of Excellence NanoCAN, University of Southern Denmark, Odense, Denmark; Department of Cancer and Inflammation Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Jan Mollenhauer
- Lundbeckfonden Center of Excellence NanoCAN, University of Southern Denmark, Odense, Denmark; Department of Cancer and Inflammation Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Henrik J Ditzel
- Lundbeckfonden Center of Excellence NanoCAN, University of Southern Denmark, Odense, Denmark; Department of Cancer and Inflammation Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark; Department of Oncology, Odense University Hospital, Odense, Denmark.
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The scavenging capacity of DMBT1 is impaired by germline deletions. Immunogenetics 2017; 69:401-407. [PMID: 28364129 PMCID: PMC5435793 DOI: 10.1007/s00251-017-0982-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 03/27/2017] [Indexed: 12/31/2022]
Abstract
The Scavenger Receptor Cysteine-Rich (SRCR) proteins are an archaic group of proteins characterized by the presence of multiple SRCR domains. They are membrane-bound or secreted proteins, which are generally related to host defense systems in animals. Deleted in Malignant Brain Tumors 1 (DMBT1) is a SRCR protein which is secreted in mucosal fluids and involved in host defense by pathogen binding by its SRCR domains. Genetic polymorphism within DMBT1 leads to DMBT1-alleles giving rise to polypeptides with interindividually different numbers of SRCR domains, ranging from 8 SRCR domains (encoded by 6 kb DMBT1 variant) to 13 SRCR domains (encoded by the 8 kb DMBT1 variant). In the present study, we have investigated whether reduction from 13 to 8 amino-terminal SRCR domains leads to reduction of bacterial binding. The 6 kb variant bound ~20–45% less bacteria compared to the 8 kb variant. These results support the hypothesis that genetic variation in DMBT1 may influence microbial defense.
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