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Foo ACY, Thompson PM, Perera L, Arora S, DeRose EF, Williams J, Mueller GA. Hydrophobic ligands influence the structure, stability, and processing of the major cockroach allergen Bla g 1. Sci Rep 2019; 9:18294. [PMID: 31797892 PMCID: PMC6893020 DOI: 10.1038/s41598-019-54689-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 11/13/2019] [Indexed: 11/09/2022] Open
Abstract
The cockroach allergen Bla g 1 forms a novel fold consisting of 12 amphipathic alpha-helices enclosing an exceptionally large hydrophobic cavity which was previously demonstrated to bind a variety of lipids. Since lipid-dependent immunoactivity is observed in numerous allergens, understanding the structural basis of this interaction could yield insights into the molecular determinants of allergenicity. Here, we report atomic modelling of Bla g 1 bound to both fatty-acid and phospholipids ligands, with 8 acyl chains suggested to represent full stoichiometric binding. This unusually high occupancy was verified experimentally, though both modelling and circular dichroism indicate that the general alpha-helical structure is maintained regardless of cargo loading. Fatty-acid cargoes significantly enhanced thermostability while inhibiting cleavage by cathepsin S, an endosomal protease essential for antigen processing and presentation; the latter of which was found to correlate to a decreased production of known T-cell epitopes. Both effects were strongly dependent on acyl chain length, with 18-20 carbons providing the maximal increase in melting temperature (~20 °C) while completely abolishing proteolysis. Diacyl chain cargoes provided similar enhancements to thermostability, but yielded reduced levels of proteolytic resistance. This study describes how the biophysical properties of Bla g 1 ligand binding and digestion may relate to antigen processing, with potential downstream implications for immunogenicity.
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Affiliation(s)
- Alexander C Y Foo
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, HHS, Research Triangle Park, NC, 27709, North Carolina, USA
| | - Peter M Thompson
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, HHS, Research Triangle Park, NC, 27709, North Carolina, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, HHS, Research Triangle Park, NC, 27709, North Carolina, USA
| | - Simrat Arora
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, HHS, Research Triangle Park, NC, 27709, North Carolina, USA
| | - Eugene F DeRose
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, HHS, Research Triangle Park, NC, 27709, North Carolina, USA
| | - Jason Williams
- Mass Spectrometry Research and Support Group, National Institute of Environmental Health Sciences, NIH, HHS, Research Triangle Park, NC, 27709, North Carolina, USA
| | - Geoffrey A Mueller
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, HHS, Research Triangle Park, NC, 27709, North Carolina, USA.
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2
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Lai KM. Are Cockroaches an Important Source of Indoor Endotoxins? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:E91. [PMID: 28106812 PMCID: PMC5295341 DOI: 10.3390/ijerph14010091] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 01/13/2017] [Accepted: 01/16/2017] [Indexed: 11/16/2022]
Abstract
Endotoxins are common indoor biocontaminants. Their levels have been shown to link to many sources and factors. One of them is cockroach infestation but the role of cockroaches and contamination mechanisms are unclear. We hypothesized that not only is cockroach infestation a sign of poor hygiene, but it also contributes to indoor endotoxins via fecal contamination. In this study, different cockroach species were caught in homes. The endotoxin and allergen levels and their ratios in cockroach feces were determined. To estimate the amount of indoor endotoxins that originated from cockroaches, a new approach of using these new cockroach endotoxin and allergen ratios to compare with environmental data was employed. We found that Supella (S.) longipalpa, Periplaneta (P.) australasiae, and Blattella (B.) germanica were dominant in homes. On average, P. australasiae feces had a higher level but greater variation of endotoxins. B. germanica feces had the highest levels of allergens measured. Depending on environmental bacterial load and the type of cockroaches present, cockroach endotoxins in the environment may vary greatly. Cockroaches directly contribute to indoor endotoxins rather than just being a sign of poor hygiene. The type and extent of cockroach infestation should be taken into consideration when assessing and remediating indoor endotoxin contamination.
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Affiliation(s)
- Ka Man Lai
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
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Dietrich DE, Martin AD, Brogden KA. Human β-defensin HBD3 binds to immobilized Bla g2 from the German cockroach (Blattella germanica). Peptides 2014; 53:265-9. [PMID: 24495736 PMCID: PMC3992933 DOI: 10.1016/j.peptides.2014.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/21/2014] [Accepted: 01/21/2014] [Indexed: 01/28/2023]
Abstract
Human β-defensin 3 (HBD3) is a small, well-characterized peptide in mucosal secretions with broad antimicrobial activities and diverse innate immune functions. Among these functions is the ability of HBD3 to bind to antigens. In this study, we hypothesize that HBD3 binds to the allergen Bla g2 from the German cockroach (Blattella germanica). The ability of HBD1 (used as a control β-defensin) and HBD3 to bind to Bla g2 and human serum albumin (HSA, used as a control ligand) was assessed using the SensíQ Pioneer surface plasmon resonance (SPR) spectroscopy biosensor system. HBD1 was observed to bind weakly to Bla g2, while HBD3 demonstrated a stronger affinity for the allergen. HBD3 was assessed under two buffer conditions using 0.15 M and 0.3 M NaCl to control the electrostatic attraction of the peptide to the chip surface. The apparent K(D) of HBD3 binding Bla g2 was 5.9±2.1 μM and for binding HSA was 4.2±0.7 μM, respectively. Thus, HBD3, found in mucosal secretions has the ability to bind to allergens like Bla g2 possibly by electrostatic interaction, and may alter the ability of Bla g2 to induce localized allergic and/or inflammatory mucosal responses.
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Affiliation(s)
- Deborah E Dietrich
- Dows Institute for Dental Research, College of Dentistry, The University of Iowa, Iowa City, IA 52242, USA
| | - Aaron D Martin
- SensíQ Technologies Inc., 800 Research Parkway, Suite 100, Oklahoma City, OK 73104, USA
| | - Kim A Brogden
- Dows Institute for Dental Research, College of Dentistry, The University of Iowa, Iowa City, IA 52242, USA; Department of Periodontics and Dows Institute for Dental Research, N423 DSB, College of Dentistry, The University of Iowa, 801 Newton Road, Iowa City, IA 52242, USA.
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4
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Herbert C, Siegle JS, Shadie AM, Nikolaysen S, Garthwaite L, Hansbro NG, Foster PS, Kumar RK. Development of asthmatic inflammation in mice following early-life exposure to ambient environmental particulates and chronic allergen challenge. Dis Model Mech 2012; 6:479-88. [PMID: 23223614 PMCID: PMC3597029 DOI: 10.1242/dmm.010728] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Childhood exposure to environmental particulates increases the risk of development of asthma. The underlying mechanisms might include oxidant injury to airway epithelial cells (AEC). We investigated the ability of ambient environmental particulates to contribute to sensitization via the airways, and thus to the pathogenesis of childhood asthma. To do so, we devised a novel model in which weanling BALB/c mice were exposed to both ambient particulate pollutants and ovalbumin for sensitization via the respiratory tract, followed by chronic inhalational challenge with a low mass concentration of the antigen. We also examined whether these particulates caused oxidant injury and activation of AEC in vitro. Furthermore, we assessed the potential benefit of minimizing oxidative stress to AEC through the period of sensitization and challenge by dietary intervention. We found that characteristic features of asthmatic inflammation developed only in animals that received particulates at the same time as respiratory sensitization, and were then chronically challenged with allergen. However, these animals did not develop airway hyper-responsiveness. Ambient particulates induced epithelial injury in vitro, with evidence of oxidative stress and production of both pro-inflammatory cytokines and Th2-promoting cytokines such as IL-33. Treatment of AEC with an antioxidant in vitro inhibited the pro-inflammatory cytokine response to these particulates. Ambient particulates also induced pro-inflammatory cytokine expression following administration to weanling mice. However, early-life dietary supplementation with antioxidants did not prevent the development of an asthmatic inflammatory response in animals that were exposed to particulates, sensitized and challenged. We conclude that injury to airway epithelium by ambient environmental particulates in early life is capable of promoting the development of an asthmatic inflammatory response in sensitized and antigen-challenged mice. These findings are likely to be relevant to the induction of childhood asthma.
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Affiliation(s)
- Cristan Herbert
- Inflammation and Infection Research Centre, School of Medical Sciences, University of New South Wales, Sydney, 2052, Australia
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Kulhankova K, George CL, Kline JN, Darling M, Thorne PS. Endotoxin inhalation alters lung development in neonatal mice. Am J Ind Med 2012; 55:1146-58. [PMID: 22576659 PMCID: PMC3549999 DOI: 10.1002/ajim.22061] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/06/2012] [Indexed: 11/11/2022]
Abstract
BACKGROUND Childhood asthma is a significant public health problem. Epidemiologic evidence suggests an association between childhood asthma exacerbations and early life exposure to environmental endotoxin. Although the pathogenesis of endotoxin-induced adult asthma is well studied, questions remain about the impact of environmental endotoxin on pulmonary responsiveness in early life. METHODS We developed a murine model of neonatal/juvenile endotoxin exposures approximating those in young children and evaluated the lungs inflammatory and remodeling responses. RESULTS Persistent lung inflammation induced by the inhalation of endotoxin in early life was demonstrated by the influx of inflammatory cells and pro-inflammatory mediators to the airways and resulted in abnormal alveolarization. CONCLUSIONS Results of this study advance the understanding of the impact early life endotoxin inhalation has on the lower airways, and demonstrates the importance of an experimental design that approximates environmental exposures as they occur in young children.
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Affiliation(s)
- Katarina Kulhankova
- Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA, USA
- Environmental Health Sciences Research Center, University of Iowa, Iowa City, IA, USA
- Department of Pathology, University of Iowa, Iowa City, IA, USA
| | | | - Joel N. Kline
- Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA, USA
- Environmental Health Sciences Research Center, University of Iowa, Iowa City, IA, USA
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
| | | | - Peter S. Thorne
- Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA, USA
- Environmental Health Sciences Research Center, University of Iowa, Iowa City, IA, USA
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Guibas GV, Makris M, Spandou E, Priftis KN. Exposure of immunologically naive laboratory rodents to antigen via the airways. Where does tolerance stop and sensitization begin? Clin Exp Allergy 2012; 42:1552-65. [DOI: 10.1111/j.1365-2222.2012.03974.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
| | - M. Makris
- Allergy Unit; 2nd Department of dermatology and Venereology; Medical School; “Attikon” General University Hospital; Athens; Greece
| | - E. Spandou
- Laboratory of Experimental Physiology; Medical School; Aristotle University of Thessaloniki; Thessaloniki; Greece
| | - K. N. Priftis
- 3rd Department of Pediatrics; Medical School; “Attikon” General University Hospital; Athens; Greece
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Helyes Z, Hajna Z. Endotoxin-Induced Airway Inflammation and Asthma Models. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2012. [DOI: 10.1007/978-1-62703-077-9_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Influenza A facilitates sensitization to house dust mite in infant mice leading to an asthma phenotype in adulthood. Mucosal Immunol 2011; 4:682-94. [PMID: 21881572 DOI: 10.1038/mi.2011.35] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The origins of allergic asthma, particularly in infancy, remain obscure. Respiratory viral infections and allergen sensitization in early life have been associated with asthma in young children. However, a causal link has not been established. We investigated whether an influenza A infection in early life alters immune responses to house dust mite (HDM) and promotes an asthmatic phenotype later in life. Neonatal (8-day-old) mice were infected with influenza virus and 7 days later, exposed to HDM for 3 weeks. Unlike adults, neonatal mice exposed to HDM exhibited negligible immune responsiveness to HDM, but not to influenza A. HDM responsiveness in adults was associated with distinct Ly6c+ CD11b+ inflammatory dendritic cell and CD8α+ plasmacytoid (pDC) populations that were absent in HDM-exposed infant mice, suggesting an important role in HDM-mediated inflammation. Remarkably, HDM hyporesponsiveness was overcome when exposure occurred concurrently with an acute influenza infection; young mice now displayed robust allergen-specific immunity, allergic inflammation, and lung remodeling. Remodeling persisted into early adulthood, even after prolonged discontinuation of allergen exposure and was associated with marked impairment of lung function. Our data demonstrate that allergen exposure coincident with acute viral infection in early life subverts constitutive allergen hyporesponsiveness and imprints an asthmatic phenotype in adulthood.
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Kim J, Natarajan S, Vaickus LJ, Bouchard JC, Beal D, Cruikshank WW, Remick DG. Diesel exhaust particulates exacerbate asthma-like inflammation by increasing CXC chemokines. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:2730-9. [PMID: 21967814 DOI: 10.1016/j.ajpath.2011.08.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Revised: 07/11/2011] [Accepted: 08/10/2011] [Indexed: 11/17/2022]
Abstract
Particulate matter heavily pollutes the urban atmosphere, and several studies show a link between increased ambient particulate air pollution and exacerbation of pre-existing pulmonary diseases, including asthma. We investigated how diesel exhaust particulates (DEPs) aggravate asthma-like pulmonary inflammation in a mouse model of asthma induced by a house dust extract (HDE) containing cockroach allergens and endotoxin. BALB/c mice were exposed to three pulmonary challenges via hypopharyngeal administration of an HDE collected from the home of an asthmatic child. One hour before each pulmonary challenge, mice were exposed to DEP or PBS. Pulmonary inflammation was assessed by histological features, oxidative stress, respiratory physiological features, inflammatory cell recruitment, and local CXC chemokine production. To prove the role of CXC chemokines in the augmented inflammation, CXC chemokine-specific antibodies were delivered to the lungs before DEP exposure. DEP exacerbated HDE-induced airway inflammation, with increased airway mucus production, oxidative stress, inflammatory cell infiltration, bronchoalveolar lavage concentrations of CXC chemokines, and airway hyperreactivity. Neutralization of airway keratinocyte-derived chemokine and macrophage inflammatory protein-2 significantly improves the respiratory function in addition to decreasing the infiltration of neutrophils and eosinophils. Blocking the chemokines also decreased airway mucus production. These results demonstrate that DEP exacerbates airway inflammation induced by allergen through increased pulmonary expression of the CXC chemokines (keratinocyte-derived chemokine and macrophage inflammatory protein-2).
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Affiliation(s)
- Jiyoun Kim
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
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Chu HW, Lloyd CM, Karmaus W, Maestrelli P, Mason P, Salcedo G, Thaikoottathil J, Wardlaw AJ. Developments in the field of allergy in 2009 through the eyes of Clinical and Experimental Allergy. Clin Exp Allergy 2011; 40:1611-31. [PMID: 21039970 DOI: 10.1111/j.1365-2222.2010.03625.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In 2009 the journal published in the region of 200 papers including reviews, editorials, opinion pieces and original papers that ran the full gamut of allergic disease. It is instructive to take stock of this output to determine patterns of interest and where the cutting edge lies. We have surveyed the field of allergic disease as seen through the pages of Clinical and Experimental Allergy (CEA) highlighting trends, emphasizing notable observations and placing discoveries in the context of other key papers published during the year. The review is divided into similar sections as the journal. In the field of Asthma and Rhinitis CEA has contributed significantly to the debate about asthma phenotypes and expressed opinions about the cause of intrinsic asthma. It has also added its halfpennyworth to the hunt for meaningful biomarkers. In Mechanisms the considerable interest in T cell subsets including Th17 and T regulatory cells continues apace and the discipline of Epidemiology continues to invoke a steady stream of papers on risk factors for asthma with investigators still trying to explain the post-second world war epidemic of allergic disease. Experimental Models continue to make important contributions to our understanding of pathogenesis of allergic disease and in the Clinical Allergy section various angles on immunotherapy are explored. New allergens continue to be described in the allergens section to make those allergen chips even more complicated. A rich and vibrant year helpfully summarized by some of our associate editors.
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Affiliation(s)
- H W Chu
- Department of Medicine, National Jewish Health, Denver, CO, USA
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