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"NETtling" the host: Breaking of tolerance in chronic inflammation and chronic infection. J Autoimmun 2019; 88:1-10. [PMID: 29100671 DOI: 10.1016/j.jaut.2017.10.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/24/2017] [Accepted: 10/24/2017] [Indexed: 12/31/2022]
Abstract
How and why we break tolerance to self-proteins still remains a largely unanswered question. Neutrophils have been identified as a rich source of autoantigens in a wide array of autoimmune diseases that arise as a consequence of different environmental and genetic factors, e.g. rheumatoid arthritis (RA), lupus, vasculitis, cystic fibrosis (CF) etc. Specifically, neutrophil extracellular trap (NET) formation has been identified as a link between innate and adaptive immune responses in autoimmunity. Autoantigens including neutrophil granular proteins (targeted by anti-neutrophil cytoplasmic antibodies, ANCA) as well as post-translationally modified proteins, i.e. citrullinated and carbamylated proteins targeted by anti-citrullinated protein antibodies (ACPA) and anti-carbamylated protein antibodies (ACarPA), respectively, localize to the NETs. Moreover, NETs provide stimuli to dendritic cells that potentiate adaptive autoimmune responses. However, while NETs promote inflammation and appear to induce humoral autoreactivity across autoimmune diseases, the antigen specificity of autoantibodies found in these disorders is striking. These unique autoantigen signatures suggest that not all NETs are created equal and that the environment in which NETs arise shapes their disease-specific character. In this review article, we discuss the effects of different stimuli on the mechanism of NET formation as well as how they contribute to antigen specificity in the breaking of immune tolerance. Specifically, we compare and contrast the autoreactive nature of NETs in two settings of chronic airway inflammation: one triggered by smoking, a recognized environmental NET stimulus in RA patients, and one mediated by Pseudomonas aeruginosa, the most prevalent lung pathogen in CF patients. Finally, we draw attention to novel findings that, together with the specific environmental/chemical stimuli, should be taken into account when investigating how and why antigen specificity arises in the context of NET formation.
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Song Y, Kadiyala U, Weerappuli P, Valdez JJ, Yalavarthi S, Louttit C, Knight JS, Moon JJ, Weiss DS, VanEpps JS, Takayama S. Antimicrobial Microwebs of DNA-Histone Inspired from Neutrophil Extracellular Traps. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1807436. [PMID: 30698844 PMCID: PMC6467213 DOI: 10.1002/adma.201807436] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/16/2019] [Indexed: 05/07/2023]
Abstract
Neutrophil extracellular traps (NETs) are decondensed chromatin networks released by neutrophils that can trap and kill pathogens but can also paradoxically promote biofilms. The mechanism of NET functions remains ambiguous, at least in part, due to their complex and variable compositions. To unravel the antimicrobial performance of NETs, a minimalistic NET-like synthetic structure, termed "microwebs," is produced by the sonochemical complexation of DNA and histone. The prepared microwebs have structural similarity to NETs at the nanometer to micrometer dimensions but with well-defined molecular compositions. Microwebs prepared with different DNA to histone ratios show that microwebs trap pathogenic Escherichia coli in a manner similar to NETs when the zeta potential of the microwebs is positive. The DNA nanofiber networks and the bactericidal histone constituting the microwebs inhibit the growth of E. coli. Moreover, microwebs work synergistically with colistin sulfate, a common and a last-resort antibiotic, by targeting the cell envelope of pathogenic bacteria. The synthesis of microwebs enables mechanistic studies not possible with NETs, and it opens new possibilities for constructing biomimetic bacterial microenvironments to better understand and predict physiological pathogen responses.
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Affiliation(s)
- Yang Song
- Wallace H Coulter Department of Biomedical Engineering & Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology & Emory School of Medicine, Atlanta, GA, 30332, USA
| | - Usha Kadiyala
- Department of Emergency Medicine, Michigan Center for Integrative Research in Critical Care, Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Priyan Weerappuli
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jordan J. Valdez
- Emory Antibiotic Resistance Center, Emory Vaccine Center, School of Medicine, Emory University, Atlanta, GA, 30307, USA
| | | | - Cameron Louttit
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jason S. Knight
- Division of Rheumatology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - James J. Moon
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - David S. Weiss
- Emory Antibiotic Resistance Center, Emory Vaccine Center, School of Medicine, Emory University, Atlanta, GA, 30307, USA
| | - J. Scott VanEpps
- Department of Emergency Medicine, Michigan Center for Integrative Research in Critical Care, Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Shuichi Takayama
- Wallace H Coulter Department of Biomedical Engineering & Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology & Emory School of Medicine, Atlanta, GA, 30332, USA
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Reaves BJ, Wallis C, McCoy CJ, Lorenz WW, Rada B, Wolstenholme AJ. Recognition and killing of Brugia malayi microfilariae by human immune cells is dependent on the parasite sample and is not altered by ivermectin treatment. Int J Parasitol Drugs Drug Resist 2018; 8:587-595. [PMID: 30279092 PMCID: PMC6287470 DOI: 10.1016/j.ijpddr.2018.09.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/14/2018] [Accepted: 09/16/2018] [Indexed: 12/20/2022]
Abstract
Mass administration of macrocyclic lactones targets the transmission of the causative agents of lymphatic filariasis to their insect vectors by rapidly clearing microfilariae (Mf) from the circulation. It has been proposed that the anti-filarial action of these drugs may be mediated through the host immune system. We recently developed an in vitro assay for monitoring the attachment to and killing of B. malayi Mf by human neutrophils (PMNs) and monocytes (PBMCs), however, the levels of both cell to worm attachment and leukocyte mediated Mf killing varied greatly between individual experiments. To determine whether differences in an individual's immune cells or the Mf themselves might account for the variability in survival, PMNs and PBMCs were isolated from 12 donors every week for 4 weeks and the cells used for survival assays with a different batch of Mf, thereby keeping donors constant but varying the Mf sample. Results from these experiments indicate that, overall, killing is Mf-rather than donor-dependent. To assess whether ivermectin (IVM) or diethylcarbamazine (DEC) increase killing, Mf were incubated either alone or with immune cells in the presence of IVM or DEC. Neither drug induced a significant difference in the survival of Mf whether cultured with or without cells, with the exception of DEC at 2 h post incubation. In addition, human PBMCs and PMNs were incubated with IVM or DEC for 1 h or 16 h prior to RNA extraction and Illumina sequencing. Although donor-to-donor variation may mask subtle differences in gene expression, principle component analysis of the RNASeq data indicates that there is no significant change in the expression of any genes from the treated cells versus controls. Together these data suggest that IVM and DEC have little direct effect on immune cells involved in the rapid clearance of Mf from the circulation.
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Affiliation(s)
- Barbara J Reaves
- Department of Infectious Diseases, University of Georgia, Athens, GA, 30602, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA.
| | - Connor Wallis
- Department of Infectious Diseases, University of Georgia, Athens, GA, 30602, USA.
| | - Ciaran J McCoy
- Department of Infectious Diseases, University of Georgia, Athens, GA, 30602, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA.
| | - W Walter Lorenz
- Institute for Bioinformatics, University of Georgia, Athens, GA, 30602, USA.
| | - Balazs Rada
- Department of Infectious Diseases, University of Georgia, Athens, GA, 30602, USA.
| | - Adrian J Wolstenholme
- Department of Infectious Diseases, University of Georgia, Athens, GA, 30602, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA.
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54
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Roesch EA, Nichols DP, Chmiel JF. Inflammation in cystic fibrosis: An update. Pediatr Pulmonol 2018; 53:S30-S50. [PMID: 29999593 DOI: 10.1002/ppul.24129] [Citation(s) in RCA: 161] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 06/25/2018] [Indexed: 12/13/2022]
Abstract
Inflammation plays a critical role in cystic fibrosis (CF) lung pathology and disease progression making it an active area of research and important therapeutic target. In this review, we explore the most recent research on the major contributors to the exuberant inflammatory response seen in CF as well as potential therapeutics to combat this response. Absence of functional cystic fibrosis transmembrane conductance regulator (CFTR) alters anion transport across CF airway epithelial cells and ultimately results in dehydration of the airway surface liquid. The dehydrated airway surface liquid in combination with abnormal mucin secretion contributes to airway obstruction and subsequent infection that may serve as a trigger point for inflammation. There is also evidence to suggest that airway inflammation may be excessive and sustained relative to the infectious stimuli. Studies have shown dysregulation of both pro-inflammatory mediators such as IL-17 and pro-resolution mediators including metabolites of the eicosanoid pathway. Recently, CFTR potentiators and correctors have garnered much attention in the CF community. Although these modulators address the underlying defect in CF, their impact on downstream consequences such as inflammation are not known. Here, we review pre-clinical and clinical data on the impact of CFTR modulators on inflammation. In addition, we examine other cell types including neutrophils, macrophages, and T-lymphocytes that express CFTR and contribute to the CF inflammatory response. Finally, we address challenges in developing anti-inflammatory therapies and highlight some of the most promising anti-inflammatory drugs under development for CF.
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Affiliation(s)
- Erica A Roesch
- Department of Pediatrics, Case Western Reserve University School of Medicine, Rainbow Babies and Children's Hospital, Cleveland, Ohio
| | - David P Nichols
- Department of Pediatrics, Seattle Children's Hospital, University of Washington, Seattle, Washington
| | - James F Chmiel
- Department of Pediatrics, Case Western Reserve University School of Medicine, Rainbow Babies and Children's Hospital, Cleveland, Ohio
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55
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Baker LY, Hobby CR, Siv AW, Bible WC, Glennon MS, Anderson DM, Symes SJ, Giles DK. Pseudomonas aeruginosa responds to exogenous polyunsaturated fatty acids (PUFAs) by modifying phospholipid composition, membrane permeability, and phenotypes associated with virulence. BMC Microbiol 2018; 18:117. [PMID: 30217149 PMCID: PMC6137939 DOI: 10.1186/s12866-018-1259-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 09/05/2018] [Indexed: 12/20/2022] Open
Abstract
Background Pseudomonas aeruginosa, a common opportunistic pathogen, is known to cause infections in a variety of compromised human tissues. An emerging mechanism for microbial survival is the incorporation of exogenous fatty acids to alter the cell’s membrane phospholipid profile. With these findings, we show that exogenous fatty acid exposure leads to changes in bacterial membrane phospholipid structure, membrane permeability, virulence phenotypes and consequent stress responses that may influence survival and persistence of Pseudomonas aeruginosa. Results Thin-layer chromatography and ultra performance liquid chromatography / ESI-mass spectrometry indicated alteration of bacterial phospholipid profiles following growth in the presence of polyunsaturated fatty acids (PUFAs) (ranging in carbon length and unsaturation). The exogenously supplied fatty acids were incorporated into the major bacterial phospholipids phosphatidylethanolamine and phosphatidylglycerol. The incorporation of fatty acids increased membrane permeability as judged by both accumulation and exclusion of ethidium bromide. Individual fatty acids were identified as modifying resistance to the cyclic peptide antibiotics polymyxin B and colistin, but not the beta-lactam imipenem. Biofilm formation was increased by several PUFAs and significant fluctuations in swimming motility were observed. Conclusions Our results emphasize the relevance and complexity of exogenous fatty acids in the membrane physiology and pathobiology of a medically important pathogen. P. aeruginosa exhibits versatility with regard to utilization of and response to exogenous fatty acids, perhaps revealing potential strategies for prevention and control of infection. Electronic supplementary material The online version of this article (10.1186/s12866-018-1259-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lyssa Y Baker
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Chelsea R Hobby
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Andrew W Siv
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - William C Bible
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Michael S Glennon
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Derek M Anderson
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Steven J Symes
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - David K Giles
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA.
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56
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Westerman TL, Bogomolnaya L, Andrews-Polymenis HL, Sheats MK, Elfenbein JR. The Salmonella type-3 secretion system-1 and flagellar motility influence the neutrophil respiratory burst. PLoS One 2018; 13:e0203698. [PMID: 30204776 PMCID: PMC6133356 DOI: 10.1371/journal.pone.0203698] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 08/24/2018] [Indexed: 11/28/2022] Open
Abstract
Neutrophils are innate immune response cells designed to kill invading microorganisms. One of the mechanisms neutrophils use to kill bacteria is generation of damaging reactive oxygen species (ROS) via the respiratory burst. However, during enteric salmonellosis, neutrophil-derived ROS actually facilitates Salmonella expansion and survival in the gut. This seeming paradox led us to hypothesize that Salmonella may possess mechanisms to influence the neutrophil respiratory burst. In this work, we used an in vitro Salmonella-neutrophil co-culture model to examine the impact of enteric infection relevant virulence factors on the respiratory burst of human neutrophils. We report that neutrophils primed with granulocyte-macrophage colony stimulating factor and suspended in serum containing complement produce a robust respiratory burst when stimulated with viable STm. The magnitude of the respiratory burst increases when STm are grown under conditions to induce the expression of the type-3 secretion system-1. STm mutants lacking the type-3 secretion system-1 induce less neutrophil ROS than the virulent WT. In addition, we demonstrate that flagellar motility is a significant agonist of the neutrophil respiratory burst. Together our data demonstrate that both the type-3 secretion system-1 and flagellar motility, which are established virulence factors in enteric salmonellosis, also appear to directly influence the magnitude of the neutrophil respiratory burst in response to STm in vitro.
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Affiliation(s)
- Trina L. Westerman
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, United States of America
| | - Lydia Bogomolnaya
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Bryan, TX, United States of America
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Helene L. Andrews-Polymenis
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Bryan, TX, United States of America
| | - M. Katherine Sheats
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, United States of America
| | - Johanna R. Elfenbein
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, United States of America
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57
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Haripriyan J, Omanakuttan A, Menon ND, Vanuopadath M, Nair SS, Corriden R, Nair BG, Nizet V, Kumar GB. Clove Bud Oil Modulates Pathogenicity Phenotypes of the Opportunistic Human Pathogen Pseudomonas aeruginosa. Sci Rep 2018; 8:3437. [PMID: 29467483 PMCID: PMC5821892 DOI: 10.1038/s41598-018-19771-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 01/08/2018] [Indexed: 02/01/2023] Open
Abstract
Earlier studies from our laboratory have demonstrated that clove bud oil (CBO) attenuates expression of certain virulence factors of Pseudomonas aeruginosa PAO1. Here, we probe more deeply into the effect of CBO on four pseudomonal proteases - elastase A, elastase B, protease IV and alkaline protease - each known to play key roles in disease pathogenesis. CBO inhibited the activity of these proteases present in the bacterial culture supernatant. Zymography studies indicated that these proteases can activate host matrix metalloproteases (MMPs) to establish infection, through conversion of pro-MMP-2 to active MMP-2. PAO1 is a predominant pathogen in burn wound infections and we show the modulatory effect of CBO on MMPs in an in vitro model of burn injury. Furthermore, CBO induced dose-dependent neutrophil extracellular trap formation in human neutrophils. CBO also increased the survival of C. elegans infected with PAO1, establishing an anti-infective role in a whole animal model of pathogenesis. LC-MS/MS analysis indicated that CBO treatment elicited a significant reduction of signalling molecules (Acyl-Homoserine-Lactone) involved in quorum sensing regulation. Our observations demonstrate that CBO attenuates key virulence mechanisms of this important human pathogen, while concomitantly enhancing host innate immunomodulatory functions, with potential implications for topical therapy against antibiotic-resistant infections.
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Affiliation(s)
- Jayalekshmi Haripriyan
- School of Biotechnology, Amrita University, Amrita Vishwa Vidyapeetham, Clappana P.O., Kollam, Kerala, 690525, India
| | - Athira Omanakuttan
- School of Biotechnology, Amrita University, Amrita Vishwa Vidyapeetham, Clappana P.O., Kollam, Kerala, 690525, India
| | - Nitasha D Menon
- School of Biotechnology, Amrita University, Amrita Vishwa Vidyapeetham, Clappana P.O., Kollam, Kerala, 690525, India.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Muralidharan Vanuopadath
- School of Biotechnology, Amrita University, Amrita Vishwa Vidyapeetham, Clappana P.O., Kollam, Kerala, 690525, India
| | - Sudarslal Sadasivan Nair
- School of Biotechnology, Amrita University, Amrita Vishwa Vidyapeetham, Clappana P.O., Kollam, Kerala, 690525, India
| | - Ross Corriden
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Bipin G Nair
- School of Biotechnology, Amrita University, Amrita Vishwa Vidyapeetham, Clappana P.O., Kollam, Kerala, 690525, India
| | - Victor Nizet
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.,Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 920093, USA
| | - Geetha B Kumar
- School of Biotechnology, Amrita University, Amrita Vishwa Vidyapeetham, Clappana P.O., Kollam, Kerala, 690525, India.
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Influence of Different Bacteria Strains Isolated from Septic Children on Release and Degradation of Extracellular Traps by Neutrophils from Healthy Adults. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1108:1-12. [DOI: 10.1007/5584_2018_245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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59
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Abstract
Neutrophils are innate immune phagocytes that have a central role in immune defence. Our understanding of the role of neutrophils in pathogen clearance, immune regulation and disease pathology has advanced dramatically in recent years. Web-like chromatin structures known as neutrophil extracellular traps (NETs) have been at the forefront of this renewed interest in neutrophil biology. The identification of molecules that modulate the release of NETs has helped to refine our view of the role of NETs in immune protection, inflammatory and autoimmune diseases and cancer. Here, I discuss the key findings and concepts that have thus far shaped the field of NET biology.
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Abstract
The versatile and ubiquitous
Pseudomonas aeruginosa is an opportunistic pathogen causing acute and chronic infections in predisposed human subjects. Here we review recent progress in understanding
P. aeruginosa population biology and virulence, its cyclic di-GMP-mediated switches of lifestyle, and its interaction with the mammalian host as well as the role of the type III and type VI secretion systems in
P. aeruginosa infection.
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Affiliation(s)
- Jens Klockgether
- Molecular Pathology of Cystic Fibrosis Clinical Research Group, Clinic for Paediatric Pneumology, Allergology, and Neonatology, OE 6710, Hannover Medical School, Hannover, Germany
| | - Burkhard Tümmler
- Molecular Pathology of Cystic Fibrosis Clinical Research Group, Clinic for Paediatric Pneumology, Allergology, and Neonatology, OE 6710, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hannover, Germany
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61
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Newman JW, Floyd RV, Fothergill JL. The contribution of Pseudomonas aeruginosa virulence factors and host factors in the establishment of urinary tract infections. FEMS Microbiol Lett 2017; 364:3866593. [DOI: 10.1093/femsle/fnx124] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/09/2017] [Indexed: 12/26/2022] Open
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Hoppenbrouwers T, Autar ASA, Sultan AR, Abraham TE, van Cappellen WA, Houtsmuller AB, van Wamel WJB, van Beusekom HMM, van Neck JW, de Maat MPM. In vitro induction of NETosis: Comprehensive live imaging comparison and systematic review. PLoS One 2017; 12:e0176472. [PMID: 28486563 PMCID: PMC5423591 DOI: 10.1371/journal.pone.0176472] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 04/11/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Multiple inducers of in vitro Neutrophil Extracellular Trap (NET) formation (NETosis) have been described. Since there is much variation in study design and results, our aim was to create a systematic review of NETosis inducers and perform a standardized in vitro study of NETosis inducers important in (cardiac) wound healing. METHODS In vitro NETosis was studied by incubating neutrophils with PMA, living and dead bacteria (S. aureus and E. coli), LPS, (activated) platelets (supernatant), glucose and calcium ionophore Ionomycin using 3-hour periods of time-lapse confocal imaging. RESULTS PMA is a consistent and potent inducer of NETosis. Ionomycin also consistently resulted in extrusion of DNA, albeit with a process that differs from the NETosis process induced by PMA. In our standardized experiments, living bacteria were also potent inducers of NETosis, but dead bacteria, LPS, (activated) platelets (supernatant) and glucose did not induce NETosis. CONCLUSION Our systematic review confirms that there is much variation in study design and results of NETosis induction. Our experimental results confirm that under standardized conditions, PMA, living bacteria and Ionomycin all strongly induce NETosis, but real-time confocal imaging reveal different courses of events.
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Affiliation(s)
- Tamara Hoppenbrouwers
- Department of Plastic and Reconstructive Surgery, Erasmus MC, Rotterdam, The Netherlands
- Department of Hematology, Erasmus MC, Rotterdam, The Netherlands
| | - Anouchska S. A. Autar
- Department of Hematology, Erasmus MC, Rotterdam, The Netherlands
- Department of Cardiology, Erasmus MC, Rotterdam, The Netherlands
| | - Andi R. Sultan
- Department of Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
| | - Tsion E. Abraham
- Optical Imaging Center, Department of Pathology, Erasmus MC, Rotterdam, The Netherlands
| | | | | | - Willem J. B. van Wamel
- Department of Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
| | | | - Johan W. van Neck
- Department of Plastic and Reconstructive Surgery, Erasmus MC, Rotterdam, The Netherlands
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63
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Interactions between Neutrophils and Pseudomonas aeruginosa in Cystic Fibrosis. Pathogens 2017; 6:pathogens6010010. [PMID: 28282951 PMCID: PMC5371898 DOI: 10.3390/pathogens6010010] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 03/03/2017] [Indexed: 12/23/2022] Open
Abstract
Cystic fibrosis (CF) affects 70,000 patients worldwide. Morbidity and mortality in CF is largely caused by lung complications due to the triad of impaired mucociliary clearance, microbial infections and chronic inflammation. Cystic fibrosis airway inflammation is mediated by robust infiltration of polymorphonuclear neutrophil granulocytes (PMNs, neutrophils). Neutrophils are not capable of clearing lung infections and contribute to tissue damage by releasing their dangerous cargo. Pseudomonas aeruginosa is an opportunistic pathogen causing infections in immunocompromised individuals. P. aeruginosa is a main respiratory pathogen in CF infecting most patients. Although PMNs are key to attack and clear P. aeruginosa in immunocompetent individuals, PMNs fail to do so in CF. Understanding why neutrophils cannot clear P. aeruginosa in CF is essential to design novel therapies. This review provides an overview of the antimicrobial mechanisms by which PMNs attack and eliminate P. aeruginosa. It also summarizes current advances in our understanding of why PMNs are incapable of clearing P. aeruginosa and how this bacterium adapts to and resists PMN-mediated killing in the airways of CF patients chronically infected with P. aeruginosa.
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64
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Rada B. Neutrophil extracellular trap release driven by bacterial motility: Relevance to cystic fibrosis lung disease. Commun Integr Biol 2017; 10:e1296610. [PMID: 28451056 PMCID: PMC5398203 DOI: 10.1080/19420889.2017.1296610] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/10/2017] [Accepted: 02/13/2017] [Indexed: 10/28/2022] Open
Abstract
Neutrophil extracellular trap (NET) formation represents a unique effector function of neutrophils (PMN). The mechanism of NET release in response to bacteria is largely unknown. We studied the process by which Pseudomonas aeruginosa, an opportunistic pathogen, interacts with primary PMNs, and found that flagellar swimming motility of the bacterium is essential for inducing NET extrusion. Cystic fibrosis (CF) lung disease is associated with P. aeruginosa infection and PMN-dominated inflammation. Although NETs are abundant in CF airways, the main factors triggering NET release in CF remain unclear. Our study implicates that motile P. aeruginosa is a strong NET-inducer in CF. In early stages of CF lung disease flagellated, motile isolates of P. aeruginosa are characteristic and their interactions with PMNs could lead to NET formation. In chronic CF, P. aeruginosa down-regulates its flagellum expression to avoid recognition by the immune system and forms biofilms. Flagellated bacteria, however, are released from biofilms and could interact with PMNs to form NETs. Although flagellated forms likely represent only a small fraction of the total P. aeruginosa load in chronic CF, NET release induced by them could have a significant impact on inflammation and lung function since flagellated forms trigger the most robust response of the immune system including PMNs. Overall, we speculate that NET formation driven by motile P. aeruginosa could be a novel, significant contributor to pathogenesis at both, early and late stages of CF lung disease.
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Affiliation(s)
- Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
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