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Ashtiwi NM, Kim SO, Chandler JD, Rada B. The therapeutic potential of thiocyanate and hypothiocyanous acid against pulmonary infections. Free Radic Biol Med 2024; 219:104-111. [PMID: 38608822 DOI: 10.1016/j.freeradbiomed.2024.04.217] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 03/18/2024] [Accepted: 04/09/2024] [Indexed: 04/14/2024]
Abstract
Hypothiocyanous acid (HOSCN) is an endogenous oxidant produced by peroxidase oxidation of thiocyanate (SCN-), an ubiquitous sulfur-containing pseudohalide synthesized from cyanide. HOSCN serves as a potent microbicidal agent against pathogenic bacteria, viruses, and fungi, functioning through thiol-targeting mechanisms, independent of currently approved antimicrobials. Additionally, SCN- reacts with hypochlorous acid (HOCl), a highly reactive oxidant produced by myeloperoxidase (MPO) at sites of inflammation, also producing HOSCN. This imparts both antioxidant and antimicrobial potential to SCN-. In this review, we discuss roles of HOSCN/SCN- in immunity and potential therapeutic implications for combating infections.
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Affiliation(s)
- Nuha Milad Ashtiwi
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Susan O Kim
- Pediatrics, Division of Pulmonary, Allergy & Immunology, Cystic Fibrosis, and Sleep Medicine, Emory University, Atlanta, GA, USA
| | - Joshua D Chandler
- Pediatrics, Division of Pulmonary, Allergy & Immunology, Cystic Fibrosis, and Sleep Medicine, Emory University, Atlanta, GA, USA; Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
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Krepuska M, Mayer B, Vitale-Cross L, Myneni VD, Boyajian MK, Németh K, Szalayova I, Cho T, McClain-Caldwell I, Gingerich AD, Han H, Westerman M, Rada B, Mezey É. Bone marrow stromal cell-derived hepcidin has antimicrobial and immunomodulatory activities. Sci Rep 2024; 14:3986. [PMID: 38368463 PMCID: PMC10874407 DOI: 10.1038/s41598-024-54227-1] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 02/09/2024] [Indexed: 02/19/2024] Open
Abstract
Bone marrow stromal cells (BMSCs) have immunomodulatory activities in numerous species and have been used in clinical trials. BMSCs also make antibacterial agents. Since hepcidin is known to have antimicrobial effects in fish, we wondered if it might also be used as an antimicrobial agent by mammalian BMSCs. In the present study, we show hepcidin expression in both mouse (mBMSC) and human BMSCs (hBMSC). We observed a hBMSC hepcidin-dependent degradation of ferroportin in HEK-293 reporter cells in vitro. In human and mouse bone marrows (BM) we detected hepcidin-positive BMSCs in close proximity to hematopoietic progenitors. The conditioned culture medium of hBMSCs significantly reduced bacterial proliferation that was partially blocked by a hepcidin-neutralizing antibody. Similarly, medium in which hepcidin-deficient (Hamp-/-) mouse BMSCs had been grown was significantly less effective in reducing bacterial counts than the medium of wild-type cells. In a zymosan-induced peritonitis mouse model we found that mBMSC-derived hepcidin reduced the number of invading polymorphonuclear (PMN) cells in the peritoneal cavity. Our results show that BMSC-derived hepcidin has antimicrobial properties in vitro and also reduces inflammation in vivo. We conclude that hepcidin should be added to the expanding arsenal of agents available to BMSCs to fight infections and inflammation.
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Affiliation(s)
- Miklós Krepuska
- National Institutes of Health, NIDCR, ASCS, Bethesda, MD, USA
- Department of Neuroradiology, University Hospital Zürich, Zürich, Switzerland
| | - Balázs Mayer
- National Institutes of Health, NIDCR, ASCS, Bethesda, MD, USA
- Stem Cell Laboratory, Department of Dermatology, Venereology and Dermato-Oncology, Semmelweis University, Budapest, Hungary
| | | | - Vamsee D Myneni
- National Institutes of Health, NIDCR, ASCS, Bethesda, MD, USA
| | | | - Krisztián Németh
- National Institutes of Health, NIDCR, ASCS, Bethesda, MD, USA
- Stem Cell Laboratory, Department of Dermatology, Venereology and Dermato-Oncology, Semmelweis University, Budapest, Hungary
| | | | - Ted Cho
- National Institutes of Health, NIDCR, ASCS, Bethesda, MD, USA
| | | | - Aaron D Gingerich
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | | | | | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
| | - Éva Mezey
- National Institutes of Health, NIDCR, ASCS, Bethesda, MD, USA
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Almeida NBF, Fantone KM, Sarr D, Ashtiwi NM, Channell S, Grenfell RFQ, Martins-Filho OA, Rada B. Variant-dependent oxidative and cytokine responses of human neutrophils to SARS-CoV-2 spike protein and anti-spike IgG1 antibodies. Front Immunol 2023; 14:1255003. [PMID: 37908356 PMCID: PMC10613679 DOI: 10.3389/fimmu.2023.1255003] [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: 07/08/2023] [Accepted: 09/25/2023] [Indexed: 11/02/2023] Open
Abstract
Introduction Severe forms of COVID-19, the disease caused by SARS-CoV-2, are characterized by acute respiratory distress syndrome, robust lung inflammation and death in some patients. Strong evidence has been accumulating that polymorphonuclear neutrophilic granulocytes (PMN) play an important role in the pathophysiology of severe COVID-19. SARS-CoV-2 directly induces in vitro PMN activation, mainly the release of neutrophil extracellular traps (NETs). However, the viral components inducing this PMN response remain unclear. Methods In this work human PMN responses were assessed in vitro in response to the spike (S) protein of two different SARS-CoV-2 variants, anti-S IgG1 antibodies or immune complexes formed by them. Production of reactive oxygen species (ROS) was measured by Diogenes-based chemiluminescence. Release of myeloperoxidase (MPO) was assessed by ELISA while secretion of a list of cytokines and growth factors was determined by high-performance multiplex cytokine assay. Results and discussion We show that the SARS-CoV-2 Omicron variant S protein and anti-spike IgG1, either alone or together, stimulate ROS production in human PMNs. We also observed that the SARS-CoV-2 Wuhan S protein and anti-S IgG1 antibody together trigger MPO release from PMNs. Based on the relevance of SARS-CoV-2 and influenza co-infections, we have also investigated the impact of influenza virus infection on the previous PMN responses to S proteins or anti-S antibodies. We did not detect any significant effect of influenza co-infection on ROS generation in PMNs. Our data also show that PMN stimulation by S proteins induced the release of different chemokines, growth factors, regulatory and proinflammatory cytokines. Overall, our findings show that the SARS-CoV-2 S protein, an anti-spike IgG1 antibody or their immune complex, promote oxidative responses of PMNs in a variant-dependent manner, contributing to a better understanding of the role of PMN responses during SARS-CoV-2 infection.
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Affiliation(s)
- Nathalie Bonatti Franco Almeida
- Department of Infectious Diseases, The University of Georgia, Athens, GA, United States
- René Rachou Institute, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Kayla Marie Fantone
- Department of Infectious Diseases, The University of Georgia, Athens, GA, United States
| | - Demba Sarr
- Department of Infectious Diseases, The University of Georgia, Athens, GA, United States
| | - Nuha Milad Ashtiwi
- Department of Infectious Diseases, The University of Georgia, Athens, GA, United States
| | - Sarah Channell
- Department of Infectious Diseases, The University of Georgia, Athens, GA, United States
| | - Rafaella Fortini Queiroz Grenfell
- Department of Infectious Diseases, The University of Georgia, Athens, GA, United States
- René Rachou Institute, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | | | - Balázs Rada
- Department of Infectious Diseases, The University of Georgia, Athens, GA, United States
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4
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Yadav R, Li QZ, Huang H, Bridges SL, Kahlenberg JM, Stecenko AA, Rada B. Cystic fibrosis autoantibody signatures associate with Staphylococcus aureus lung infection or cystic fibrosis-related diabetes. Front Immunol 2023; 14:1151422. [PMID: 37767091 PMCID: PMC10519797 DOI: 10.3389/fimmu.2023.1151422] [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: 01/26/2023] [Accepted: 08/18/2023] [Indexed: 09/29/2023] Open
Abstract
Introduction While cystic fibrosis (CF) lung disease is characterized by persistent inflammation and infections and chronic inflammatory diseases are often accompanied by autoimmunity, autoimmune reactivity in CF has not been studied in depth. Methods In this work we undertook an unbiased approach to explore the systemic autoantibody repertoire in CF using autoantibody microarrays. Results and discussion Our results show higher levels of several new autoantibodies in the blood of people with CF (PwCF) compared to control subjects. Some of these are IgA autoantibodies targeting neutrophil components or autoantigens linked to neutrophil-mediated tissue damage in CF. We also found that people with CF with higher systemic IgM autoantibody levels have lower prevalence of S. aureus infection. On the other hand, IgM autoantibody levels in S. aureus-infected PwCF correlate with lung disease severity. Diabetic PwCF have significantly higher levels of IgA autoantibodies in their circulation compared to nondiabetic PwCF and several of their IgM autoantibodies associate with worse lung disease. In contrast, in nondiabetic PwCF blood levels of IgA autoantibodies correlate with lung disease. We have also identified other autoantibodies in CF that associate with P. aeruginosa airway infection. In summary, we have identified several new autoantibodies and associations of autoantibody signatures with specific clinical features in CF.
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Affiliation(s)
- Ruchi Yadav
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, United States
| | - Quan-Zhen Li
- Department of Immunology and Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Hanwen Huang
- Department of Epidemiology & Biostatistics, College of Public Health, The University of Georgia, Athens, GA, United States
| | - S. Louis Bridges
- Department of Medicine, Hospital for Special Surgery, Division of Rheumatology, Weill Cornell Medical College, New York, NY, United States
| | - J. Michelle Kahlenberg
- Division of Rheumatology, University of Michigan, School of Medicine, Ann Arbor, MI, United States
| | - Arlene A. Stecenko
- Division of Pulmonology, Asthma, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, United States
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5
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Fantone KM, Goldberg JB, Stecenko AA, Rada B. Sputum from People with Cystic Fibrosis Reduces the Killing of Methicillin-Resistant Staphylococcus aureus by Neutrophils and Diminishes Phagosomal Production of Reactive Oxygen Species. Pathogens 2023; 12:1148. [PMID: 37764956 PMCID: PMC10538153 DOI: 10.3390/pathogens12091148] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/23/2023] [Accepted: 08/27/2023] [Indexed: 09/29/2023] Open
Abstract
Cystic fibrosis (CF) airway disease is characterized by chronic polymicrobial infections and an infiltration of neutrophils (PMNs). Staphylococcus aureus has been the most prevalent respiratory pathogen in CF. In particular, methicillin-resistant S. aureus (MRSA) represents a huge clinical burden in CF due to its association with lung disease and increased resistance to antibiotics. In CF, PMNs are unable to kill and clear MRSA. The reason for this remains largely unknown. Our study found that CF PMNs are as equally capable of killing MRSA as healthy PMNs. We show that the CF sputum, however, significantly impairs the ability of human PMNs to kill CF MRSA isolates. In the absence of CF sputum, PMNs kill MRSA via intracellular mechanisms mediated by phagocytosis, rather than extracellular mechanisms via NET formation. CF sputum does not affect the phagocytosis of MRSA via healthy or CF PMNs. Our results demonstrate that CF sputum exposure impairs phagosomal levels of reactive oxygen species (ROS) in MRSA-phagocytosing PMNs. While phagosomal co-localizations of MRSA with primary granule markers, myeloperoxidase and cathepsin D, were significantly reduced upon CF sputum exposure, that of a third azurophilic granule marker, neutrophil elastase, remained unaffected. This suggests that CF sputum does not compromise the fusion of primary granules with phagosomes but diminishes phagosomal ROS levels via another, likely more specific, mechanism. Overall, we identified the airway environment as an important factor that restricts neutrophils' oxidative microbicidal activities in CF against MRSA. These results deliver new details of the complex host-pathogen interactions present in the CF lung.
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Affiliation(s)
- Kayla M. Fantone
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA;
| | - Joanna B. Goldberg
- Division of Pulmonology, Asthma, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30602, USA; (J.B.G.); (A.A.S.)
| | - Arlene A. Stecenko
- Division of Pulmonology, Asthma, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30602, USA; (J.B.G.); (A.A.S.)
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA;
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Miller A, Fantone KM, Tucker SL, Gokanapudi N, Goldberg JB, Rada B. Short chain fatty acids reduce the respiratory burst of human neutrophils in response to cystic fibrosis isolates of Staphylococcus aureus. J Cyst Fibros 2023; 22:756-762. [PMID: 37211502 PMCID: PMC10524534 DOI: 10.1016/j.jcf.2023.04.022] [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: 08/26/2022] [Revised: 04/21/2023] [Accepted: 04/27/2023] [Indexed: 05/23/2023]
Abstract
Short chain fatty acids (SCFA) are produced by anaerobic bacteria. The most common SCFAs are acetate, propionate and butyrate. SCFAs have been implicated in several inflammatory diseases including cystic fibrosis (CF) where they are present in the airways at millimolar concentrations. Staphylococcus aureus is one of the main respiratory pathogens in CF. Polymorphonuclear neutrophil granulocytes (PMN) represent the most important immune defense the host uses against S. aureus. However, the reason why PMNs are unable to clear S. aureus in CF remains largely unclear. We hypothesized that SCFAs impair effector functions of PMNs in response to S. aureus. To test this, human PMNs were exposed to CF clinical isolates of S. aureus in vitro in the presence or absence of SCFAs and effector functions of PMNs were assessed. Our data show that SCFAs do not affect the viability of PMNs and do not stimulate the release of neutrophil extracellular traps (NET) from human PMNs. Production of reactive oxygen species (ROS), another important antimicrobial function of PMNs, on the other hand, was significantly inhibited by SCFAs in response to the bacterium. SCFAs did not compromise the ability of PMNs to kill CF isolates of S. aureus in vitro. Overall, our results provide new knowledge into the interactions between SCFAs and the immune system, and indicate that SCFAs produced by anaerobic bacteria in the CF lung could interfere with reactive oxidant production of PMNs in response to S. aureus, one of the prominent respiratory pathogens in this disease.
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Affiliation(s)
- Arthur Miller
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
| | - Kayla M Fantone
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
| | - Samantha L Tucker
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
| | - Naveen Gokanapudi
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
| | - Joanna B Goldberg
- Division of Pulmonology, Asthma, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA.
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Gupta T, Sarr D, Fantone K, Ashtiwi NM, Sakamoto K, Quinn FD, Rada B. Dual oxidase 1 is dispensable during Mycobacterium tuberculosis infection in mice. Front Immunol 2023; 14:1044703. [PMID: 36936954 PMCID: PMC10020924 DOI: 10.3389/fimmu.2023.1044703] [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: 09/14/2022] [Accepted: 02/16/2023] [Indexed: 03/06/2023] Open
Abstract
Introduction Mycobacterium tuberculosis (Mtb) is the primary cause of human tuberculosis (TB) and is currently the second most common cause of death due to a singleinfectious agent. The first line of defense against airborne pathogens, including Mtb, is the respiratory epithelium. One of the innate defenses used by respiratory epithelial cells to prevent microbial infection is an oxidative antimicrobial system consisting of the proteins, lactoperoxidase (LPO) and Dual oxidase 1 (Duox1), the thiocyanate anion (SCN-) and hydrogen peroxide (H2O2), which together lead to the generation of antimicrobial hypothiocyanite (OSCN-) in the airway lumen. OSCN- kills bacteria and viruses in vitro, but the role of this Duox1-based system in bacterial infections in vivo remains largely unknown. The goal of this study was to assess whether Duox1 contributes to the immune response against the unique respiratory pathogen, Mtb. Methods Duox1-deficient (Duox1 KO) and wild-type (WT) mice were infected with Mtb aerosols and bacterial titers, lung pathology, cytokines and immune cell recruitment were assessed. Results and discussion Mtb titers in the lung, spleen and liver were not different 30 days after infection between WT and Duox1 KO mice. Duox1 did not affect lung histology assessed at days 0, 30, and 90 post-Mtb infection. Mtb-infected Duox1 KO animals exhibited enhanced production of certain cytokines and chemokines in the airway; however, this response was not associated with significantly higher numbers of macrophages or neutrophils in the lung. B cell numbers were lower, while apoptosis was higher in the pulmonary lesions of Mtb-infected Duox1 KO mice compared to infected WT animals. Taken together, these data demonstrate that while Duox1 might influence leukocyte recruitment to inflammatory cell aggregates, Duox1 is dispensable for the overall clinical course of Mtb lung infection in a mouse model.
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Affiliation(s)
- Tuhina Gupta
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Demba Sarr
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Kayla Fantone
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Nuha Milad Ashtiwi
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Kaori Sakamoto
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Frederick D. Quinn
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
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Fantone K, Channell S, Goldberg J, Stecenko A, Rada B. 516 Cystic fibrosis sputum attenuates killing of Staphylococcus aureus by neutrophils by impairing phagolysosome fusion. J Cyst Fibros 2022. [DOI: 10.1016/s1569-1993(22)01206-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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9
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Ashtiwi NM, Sarr D, Nagy T, Reneer ZB, Tripp RA, Rada B. The Hypothiocyanite and Amantadine Combination Treatment Prevents Lethal Influenza A Virus Infection in Mice. Front Immunol 2022; 13:859033. [PMID: 35663985 PMCID: PMC9159274 DOI: 10.3389/fimmu.2022.859033] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 04/12/2022] [Indexed: 11/21/2022] Open
Abstract
The influenza virus has a large clinical burden and is associated with significant mortality and morbidity. The development of effective drugs for the treatment or prevention of influenza is important in order to reduce its impact. Adamantanes and neuraminidase inhibitors are two classes of anti-influenza drugs in which resistance has developed; thus, there is an urgent need to explore new therapeutic options. Boosting antiviral innate immune mechanisms in the airways represents an attractive approach. Hypothiocyanite (OSCN−) is produced by the airway epithelium and is effective in reducing the replication of several influenza A virus strains in vitro. It remains, however, largely unexplored whether OSCN− has such an antiviral effect in vivo. Here we determined the therapeutic potential of OSCN−, alone or in combination with amantadine (AMT), in preventing lethal influenza A virus replication in mice and in vitro. Mice intranasally infected with a lethal dose of A/Puerto Rico/8/1934 (H1N1) or A/Hong Kong/8/1968 (H3N2) were cured by the combination treatment of OSCN− and AMT. Monotherapy with OSCN− or AMT alone did not substantially improve survival outcomes. However, AMT+OSCN− treatment significantly inhibited viral replication, and in vitro treatment inhibited viral entry and nuclear transport of different influenza A virus strains (H1N1 and H3N2) including the AMT-resistant strain A/WSN/33 (H1N1). A triple combination treatment consisting of AMT, oseltamivir, and OSCN− was also tested and further inhibited in vitro viral replication of the AMT-resistant A/WSN/33 strain. These results suggest that OSCN− is a promising anti-influenza treatment option when combined with other antiviral drugs.
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Affiliation(s)
- Nuha Milad Ashtiwi
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Demba Sarr
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Tamás Nagy
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Z Beau Reneer
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Ralph A Tripp
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
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10
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Fantone K, Channell S, Goldberg J, Stecenko A, Rada B. WS12.04 Understanding the mechanism of Staphylococcus aureus killing by neutrophils in the cystic fibrosis airway environment. J Cyst Fibros 2022. [DOI: 10.1016/s1569-1993(22)00222-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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11
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Linnemann RW, Yadav R, Zhang C, Sarr D, Rada B, Stecenko AA. Serum anti-PAD4 autoantibodies are present in cystic fibrosis children and increase with age and lung disease severity. Autoimmunity 2022; 55:109-117. [PMID: 35199621 PMCID: PMC9996683 DOI: 10.1080/08916934.2021.2021193] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Cystic fibrosis (CF) lung disease begins early in childhood and is characterized by neutrophilic inflammation of the airways. Neutrophil extracellular traps (NETs) represent one mechanism by which neutrophils contribute to lung damage. The enzyme peptidylarginine deiminase 4 (PAD4) is required for NET formation. Our overall concept is that NET formation delivers PAD4 outside the neutrophil resulting in autoantibody generation, and this autoimmunity may be a novel mechanism contributing to CF lung disease progression. The aim of this study was to investigate clinical predictors of serum anti-PAD4 autoantibody (PAD4 Ab) levels in CF subjects with a wide range of ages from early childhood through middle age. We measured PAD4 Ab levels in sera from 104 CF subjects. PAD4 Abs were detectable among CF children as young as one year of age and elevated compared to paediatric healthy controls. PAD4 Ab levels increased significantly with age (r = 0.584, p <.001) and correlated with lower lung function (r = -0.481, n = 99, p <.001). PAD4 Abs were elevated in subjects with chronic Pseudomonas aeruginosa airways infection (p <.001), but not with other key clinical CF co-variates including sex, CFTR genotype, sweat chloride, pancreatic enzyme use, nutritional status, recent pulmonary exacerbations, Staphylococcus aureus, or CF-related diabetes. PAD4 Ab levels were also correlated with serum anti-double-stranded DNA IgA autoantibodies, which have similarly been shown to be elevated in CF subjects and associated with lung damage. In multivariable analysis, age and lung function remained correlated with PAD4 Ab levels. In summary, we describe novel findings of anti-PAD4 autoantibodies in CF that are present early in childhood, increase over time with age, and correlate with lung disease severity. Autoimmunity to antigens extruded by NETs appears to be an early event in CF lung disease, and airway autoimmunity related to NET formation is a potential mechanism of lung disease progression in CF.HighlightsSerum anti-PAD4 autoantibodies are detected in paediatric CF serum and are elevated compared to healthy paediatric controlsAnti-PAD4 autoantibodies increase with ageAnti-PAD4 autoantibodies correlate with lower lung function, Pseudomonas aeruginosa airway infection and anti-dsDNA IgA autoantibodies, but not with other key clinical CF co-variatesAge and lung function remain correlated with anti-PAD4 autoantibodies in multivariable analysis.
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Affiliation(s)
- Rachel W Linnemann
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Ruchi Yadav
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
| | - Chao Zhang
- Biostatistics Core, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Demba Sarr
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
| | - Arlene A Stecenko
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
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12
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Almutairi F, Sarr D, Tucker SL, Fantone K, Lee JK, Rada B. RGS10 Reduces Lethal Influenza Infection and Associated Lung Inflammation in Mice. Front Immunol 2021; 12:772288. [PMID: 34912341 PMCID: PMC8667315 DOI: 10.3389/fimmu.2021.772288] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 11/10/2021] [Indexed: 01/05/2023] Open
Abstract
Seasonal influenza epidemics represent a significant global health threat. The exacerbated immune response triggered by respiratory influenza virus infection causes severe pulmonary damage and contributes to substantial morbidity and mortality. Regulator of G-protein signaling 10 (RGS10) belongs to the RGS protein family that act as GTPase activating proteins for heterotrimeric G proteins to terminate signaling pathways downstream of G protein-coupled receptors. While RGS10 is highly expressed in immune cells, in particular monocytes and macrophages, where it has strong anti-inflammatory effects, its physiological role in the respiratory immune system has not been explored yet. Here, we show that Rgs10 negatively modulates lung immune and inflammatory responses associated with severe influenza H1N1 virus respiratory infection in a mouse model. In response to influenza A virus challenge, mice lacking RGS10 experience enhanced weight loss and lung viral titers, higher mortality and significantly faster disease onset. Deficiency of Rgs10 upregulates the levels of several proinflammatory cytokines and chemokines and increases myeloid leukocyte accumulation in the infected lung, markedly neutrophils, monocytes, and inflammatory monocytes, which is associated with more pronounced lung damage. Consistent with this, influenza-infected Rgs10-deficent lungs contain more neutrophil extracellular traps and exhibit higher neutrophil elastase activities than wild-type lungs. Overall, these findings propose a novel, in vivo role for RGS10 in the respiratory immune system controlling myeloid leukocyte infiltration, viral clearance and associated clinical symptoms following lethal influenza challenge. RGS10 also holds promise as a new, potential therapeutic target for respiratory infections.
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Affiliation(s)
- Faris Almutairi
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA, United States
| | - Demba Sarr
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Samantha L. Tucker
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Kayla Fantone
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Jae-Kyung Lee
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
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13
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Sarr D, Oliveira LJ, Russ BN, Owino SO, Middii JD, Mwalimu S, Ambasa L, Almutairi F, Vulule J, Rada B, Moore JM. Myeloperoxidase and Other Markers of Neutrophil Activation Associate With Malaria and Malaria/HIV Coinfection in the Human Placenta. Front Immunol 2021; 12:682668. [PMID: 34737733 PMCID: PMC8562302 DOI: 10.3389/fimmu.2021.682668] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 09/17/2021] [Indexed: 01/21/2023] Open
Abstract
Introduction Placental malaria (PM) is characterized by accumulation of inflammatory leukocytes in the placenta, leading to poor pregnancy outcomes. Understanding of the underlying mechanisms remains incomplete. Neutrophils respond to malaria parasites by phagocytosis, generation of oxidants, and externalization of Neutrophil Extracellular Traps (NETs). NETs drive inflammation in malaria but evidence of NETosis in PM has not been reported. Neutrophil activity in the placenta has not been directly investigated in the context of PM and PM/HIV-co-infection. Methods Using peripheral and placental plasma samples and placental tissue collected from Kenyan women at risk for malaria and HIV infections, we assessed granulocyte levels across all gravidities and markers of neutrophil activation, including NET formation, in primi- and secundigravid women, by ELISA, western blot, immunohistochemistry and immunofluorescence. Results Reduced peripheral blood granulocyte numbers are observed with PM and PM/HIV co-infection in association with increasing parasite density and placental leukocyte hemozoin accumulation. In contrast, placental granulocyte levels are unchanged across infection groups, resulting in enhanced placental: peripheral count ratios with PM. Within individuals, PM- women have reduced granulocyte counts in placental relative to peripheral blood; in contrast, PM stabilizes these relative counts, with HIV coinfection tending to elevate placental counts relative to the periphery. In placental blood, indicators of neutrophil activation, myeloperoxidase (MPO) and proteinase 3 (PRTN3), are significantly elevated with PM and, more profoundly, with PM/HIV co-infection, in association with placental parasite density and hemozoin-bearing leukocyte accumulation. Another neutrophil marker, matrix metalloproteinase (MMP9), together with MPO and PRTN3, is elevated with self-reported fever. None of these factors, including the neutrophil chemoattractant, CXCL8, differs in relation to infant birth weight or gestational age. CXCL8 and MPO levels in the peripheral blood do not differ with infection status nor associate with birth outcomes. Indicators of NETosis in the placental plasma do not vary with infection, and while structures consistent with NETs are observed in placental tissue, the results do not support an association with PM. Conclusions Granulocyte levels are differentially regulated in the peripheral and placental blood in the presence and absence of PM. PM, both with and without pre-existing HIV infection, enhances neutrophil activation in the placenta. The impact of local neutrophil activation on placental function and maternal and fetal health remains unclear. Additional investigations exploring how neutrophil activation and NETosis participate in the pathogenesis of malaria in pregnant women are needed.
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Affiliation(s)
- Demba Sarr
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Lilian J. Oliveira
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Brittany N. Russ
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Simon O. Owino
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
- Vector Biology and Control Research Centre, Kenya Medical Research Institute, Kisian, Kenya
- University of Georgia/Kenya Medical Research Institute Placental Malaria Study, Siaya District Hospital, Siaya, Kenya
- Faculty of Science, Department of Zoology, Maseno University, Maseno, Kenya
| | - Joab D. Middii
- Vector Biology and Control Research Centre, Kenya Medical Research Institute, Kisian, Kenya
- University of Georgia/Kenya Medical Research Institute Placental Malaria Study, Siaya District Hospital, Siaya, Kenya
- Kisumu Specialists Hospital Laboratory, Kisumu, Kenya
| | - Stephen Mwalimu
- Vector Biology and Control Research Centre, Kenya Medical Research Institute, Kisian, Kenya
- University of Georgia/Kenya Medical Research Institute Placental Malaria Study, Siaya District Hospital, Siaya, Kenya
- Animal and Human Health Program, International Livestock Research Institute, Nairobi, Kenya
| | - Linda Ambasa
- Vector Biology and Control Research Centre, Kenya Medical Research Institute, Kisian, Kenya
- University of Georgia/Kenya Medical Research Institute Placental Malaria Study, Siaya District Hospital, Siaya, Kenya
- #1 Heartsaved Adult Family Care, Marysville, WA, United States
| | - Faris Almutairi
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA, United States
| | - John Vulule
- Vector Biology and Control Research Centre, Kenya Medical Research Institute, Kisian, Kenya
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Julie M. Moore
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
- Vector Biology and Control Research Centre, Kenya Medical Research Institute, Kisian, Kenya
- University of Georgia/Kenya Medical Research Institute Placental Malaria Study, Siaya District Hospital, Siaya, Kenya
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14
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Abstract
Cystic Fibrosis (CF) is a genetic disease that causes chronic and severe lung inflammation and infection associated with high rates of mortality. In CF, disrupted ion exchange in the epithelium results in excessive mucus production and reduced mucociliary clearance, leading to immune system exacerbation and chronic infections with pathogens such as P. aeruginosa and S. aureus. Constant immune stimulation leads to altered immune responses including T cell impairment and neutrophil dysfunction. Specifically, CF is considered a Th17-mediated disease, and it has been proposed that both P. aeruginosa and a subset of neutrophils known as granulocytic myeloid suppressor cells (gMDSCs) play a role in T cell suppression. The exact mechanisms behind these interactions are yet to be determined, but recent works demonstrate a role for arginase-1. It is also believed that P. aeruginosa drives gMDSC function as a means of immune evasion, leading to chronic infection. Herein, we review the current literature regarding immune suppression in CF by gMDSCs with an emphasis on T cell impairment and the role of P. aeruginosa in this dynamic interaction.
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Affiliation(s)
- Samantha L Tucker
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, United States
| | - Demba Sarr
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, United States
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, United States
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15
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Almutairi F, Tucker SL, Sarr D, Rada B. PI3K/ NF-κB-dependent TNF-α and HDAC activities facilitate LPS-induced RGS10 suppression in pulmonary macrophages. Cell Signal 2021; 86:110099. [PMID: 34339853 PMCID: PMC8406451 DOI: 10.1016/j.cellsig.2021.110099] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 07/22/2021] [Accepted: 07/23/2021] [Indexed: 12/16/2022]
Abstract
Regulator of G-protein signaling 10 (RGS10) is a member of the superfamily of RGS proteins that canonically act as GTPase activating proteins (GAPs). RGS proteins accelerate GTP hydrolysis on the G-protein α subunits and result in termination of signaling pathways downstream of G protein-coupled receptors. Beyond its GAP function, RGS10 has emerged as an anti-inflammatory protein by inhibiting LPS-mediated NF-κB activation and expression of inflammatory cytokines, in particular TNF-α. Although RGS10 is abundantly expressed in resting macrophages, previous studies have shown that RGS10 expression is suppressed in macrophages following Toll-like receptor 4 (TLR4) activation by LPS. However, the molecular mechanism by which LPS induces Rgs10 silencing has not been clearly defined. The goal of the current study was to determine whether LPS silences Rgs10 expression through an NF-κB-mediated proinflammatory mechanism in pulmonary macrophages, a unique type of innate immune cells. We demonstrate that Rgs10 transcript and RGS10 protein levels are suppressed upon LPS treatment in the murine MH-S alveolar macrophage cell line. We show that pharmacological inhibition of PI3K/ NF-κB/p300 (NF-κB co-activator)/TNF-α signaling cascade and the activities of HDAC (1-3) enzymes block LPS-induced silencing of Rgs10 in MH-S cells as well as microglial BV2 cells and BMDMs. Further, loss of RGS10 generated by using CRISPR/Cas9 amplifies NF-κB phosphorylation and inflammatory gene expression following LPS treatment in MH-S cells. Together, our findings strongly provide critical insight into the molecular mechanism underlying RGS10 suppression by LPS in pulmonary macrophages.
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Affiliation(s)
- Faris Almutairi
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA; Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA, USA
| | - Samantha L Tucker
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Demba Sarr
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
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16
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Soumana IH, Linz B, Dewan KK, Sarr D, Gestal MC, Howard LK, Caulfield AD, Rada B, Harvill ET. Modeling Immune Evasion and Vaccine Limitations by Targeted Nasopharyngeal Bordetella pertussis Inoculation in Mice. Emerg Infect Dis 2021; 27:2107-2116. [PMID: 34286682 PMCID: PMC8314809 DOI: 10.3201/eid2708.203566] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Conventional pertussis animal models deliver hundreds of thousands of Bordetella pertussis bacteria deep into the lungs, rapidly inducing severe pneumonic pathology and a robust immune response. However, human infections usually begin with colonization and growth in the upper respiratory tract. We inoculated only the nasopharynx of mice to explore the course of infection in a more natural exposure model. Nasopharyngeal colonization resulted in robust growth in the upper respiratory tract but elicited little immune response, enabling prolonged and persistent infection. Immunization with human acellular pertussis vaccine, which prevents severe lung infections in the conventional pneumonic infection model, had little effect on nasopharyngeal colonization. Our infection model revealed that B. pertussis can efficiently colonize the mouse nasopharynx, grow and spread within and between respiratory organs, evade robust host immunity, and persist for months. This experimental approach can measure aspects of the infection processes not observed in the conventional pneumonic infection model.
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17
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Fantone K, Tucker SL, Miller A, Yadav R, Bernardy EE, Fricker R, Stecenko AA, Goldberg JB, Rada B. Cystic Fibrosis Sputum Impairs the Ability of Neutrophils to Kill Staphylococcus aureus. Pathogens 2021; 10:pathogens10060703. [PMID: 34200034 PMCID: PMC8229215 DOI: 10.3390/pathogens10060703] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/26/2021] [Accepted: 05/26/2021] [Indexed: 02/06/2023] Open
Abstract
Cystic fibrosis (CF) airway disease is characterized by chronic microbial infections and infiltration of inflammatory polymorphonuclear (PMN) granulocytes. Staphylococcus aureus (S. aureus) is a major lung pathogen in CF that persists despite the presence of PMNs and has been associated with CF lung function decline. While PMNs represent the main mechanism of the immune system to kill S. aureus, it remains largely unknown why PMNs fail to eliminate S. aureus in CF. The goal of this study was to observe how the CF airway environment affects S. aureus killing by PMNs. PMNs were isolated from the blood of healthy volunteers and CF patients. Clinical isolates of S. aureus were obtained from the airways of CF patients. The results show that PMNs from healthy volunteers were able to kill all CF isolates and laboratory strains of S. aureus tested in vitro. The extent of killing varied among strains. When PMNs were pretreated with supernatants of CF sputum, S. aureus killing was significantly inhibited suggesting that the CF airway environment compromises PMN antibacterial functions. CF blood PMNs were capable of killing S. aureus. Although bacterial killing was inhibited with CF sputum, PMN binding and phagocytosis of S. aureus was not diminished. The S. aureus-induced respiratory burst and neutrophil extracellular trap release from PMNs also remained uninhibited by CF sputum. In summary, our data demonstrate that the CF airway environment limits killing of S. aureus by PMNs and provides a new in vitro experimental model to study this phenomenon and its mechanism.
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Affiliation(s)
- Kayla Fantone
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA; (K.F.); (S.L.T.); (A.M.); (R.Y.); (R.F.)
| | - Samantha L. Tucker
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA; (K.F.); (S.L.T.); (A.M.); (R.Y.); (R.F.)
| | - Arthur Miller
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA; (K.F.); (S.L.T.); (A.M.); (R.Y.); (R.F.)
| | - Ruchi Yadav
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA; (K.F.); (S.L.T.); (A.M.); (R.Y.); (R.F.)
| | - Eryn E. Bernardy
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA; (E.E.B.); (A.A.S.); (J.B.G.)
| | - Rachel Fricker
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA; (K.F.); (S.L.T.); (A.M.); (R.Y.); (R.F.)
| | - Arlene A. Stecenko
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA; (E.E.B.); (A.A.S.); (J.B.G.)
| | - Joanna B. Goldberg
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA; (E.E.B.); (A.A.S.); (J.B.G.)
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA; (K.F.); (S.L.T.); (A.M.); (R.Y.); (R.F.)
- Correspondence:
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18
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Almutairi F, Rada B. The PKC
‐δ/ NF‐κB/p300/
TNFα signaling cascade and HDAC activity facilitate LPS‐induced Rgs10 silencing in pulmonary macrophages Faris Almutairi
1,2
and Balázs Rada
2
1
Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia, USA.
2
Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.02941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Faris Almutairi
- Pharmaceutical and Biomedical SciencesUniversity of GeorgiaAthensGA
| | - Balázs Rada
- Department of Infectious DiseasesUniversity of GeorgiaAthensGA
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19
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Abstract
Dual oxidase 1 (DUOX1) is a member of the protein family of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases. DUOX1 has several normal physiological, immunological, and biochemical functions in different parts of the body. Dysregulated oxidative metabolism interferes with various disease pathologies and numerous therapeutic options are based on targeting cellular redox pathways. DUOX1 forms an important enzymatic source of biological oxidants, and DUOX1 expression is frequently dysregulated in various diseases. While this review shortly addresses the biochemical and cellular properties and proposed physiological roles of DUOX1, its main purpose is to summarize the current knowledge with respect to the potential role of DUOX1 enzyme in disease pathology, especially in mammalian organisms. Although DUOX1 is normally prominently expressed in epithelial lineages, it is frequently silenced in epithelial-derived cancers by epigenetic mechanisms. While an abundance of information is available on DUOX1 transcription in different diseases, an increasing number of mechanistic studies indicate a causative relationship between DUOX1 function and disease pathophysiology. Additionally, specific functions of the DUOX1 maturation factor, DUOXA1, will also be addressed. Lastly, urgent and outstanding questions on the field of DUOX1 will be discussed that could provide valuable new diagnostic tools and novel therapeutic options.
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Affiliation(s)
- Nuha Milad Ashtiwi
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Demba Sarr
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
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20
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Tucker SL, Sarr D, Rada B. Neutrophil extracellular traps are present in the airways of ENaC-overexpressing mice with cystic fibrosis-like lung disease. BMC Immunol 2021; 22:7. [PMID: 33478382 PMCID: PMC7819174 DOI: 10.1186/s12865-021-00397-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 01/10/2021] [Indexed: 12/13/2022] Open
Abstract
Background Neutrophils are key components of the exacerbated inflammation and tissue damage in cystic fibrosis (CF) airways. Neutrophil extracellular traps (NETs) trap and kill extracellular pathogens. While NETs are abundant in the airways of CF patients and have been hypothesized to contribute to lung damage in CF, the in vivo role of NETs remains controversial, partially due to lack of appropriate animal models. The goal of this study was to detect NETs and to further characterize neutrophil-mediated inflammation in the airways of mice overexpressing the epithelial sodium channel (βENaC-Tg mice on C57BL/6 background) in their lung with CF-like airway disease, in the absence of any apparent bacterial infections. Methods Histology scoring of lung tissues, flow cytometry, multiplex ELISA, immunohistochemistry and immunofluorescence were used to characterize NETs and the airway environment in uninfected, βENaC-Tg mice at 6 and 8 weeks of age, the most chronic time points so far studied in this model. Results Excessive neutrophilic infiltration characterized the lungs of uninfected, βENaC-Tg mice at 6 and 8 weeks of age. The bronchoalveolar lavage fluid (BALF) of βENaC-Tg mice contains increased levels of CF-associated cytokines and chemokines: KC, MIP-1α/β, MCP-1, G-CSF, IL-5, and IL-6. The BALF of βENaC-Tg mice contain MPO-DNA complexes, indicative of the presence of NETs. Immunofluorescence and flow cytometry of BALF neutrophils and lung tissues demonstrated increased histone citrullination, a NET-specific marker, in βENaC-Tg mice. Conclusions NETs are detected in the airways of βENaC-Tg mice, in the absence of bacterial infections. These data demonstrate the usefulness of the βENaC-Tg mouse to serve as a model for studying the role of NETs in chronic CF airway inflammation. Supplementary Information The online version contains supplementary material available at 10.1186/s12865-021-00397-w.
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Affiliation(s)
- Samantha L Tucker
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
| | - Demba Sarr
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA.
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21
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Fantone K, Miller A, Fricker R, Yadav R, Stecenko A, Rada B. P114 Neutrophil effector responses to cystic fibrosis clinical isolates of Pseudomonas aeruginosa. J Cyst Fibros 2021. [DOI: 10.1016/s1569-1993(21)01140-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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22
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Tucker S, Fejes Z, Li QZ, Nagy B, Rada B. P131 The systemic IgA autoantibody profile of adult cystic fibrosis. J Cyst Fibros 2021. [DOI: 10.1016/s1569-1993(21)01157-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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23
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Thomas C, Nothaft H, Yadav R, Fodor C, Alemka A, Oni O, Bell M, Rada B, Szymanski CM. Characterization of ecotin homologs from Campylobacter rectus and Campylobacter showae. PLoS One 2020; 15:e0244031. [PMID: 33378351 PMCID: PMC7773321 DOI: 10.1371/journal.pone.0244031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 07/28/2020] [Accepted: 12/01/2020] [Indexed: 12/18/2022] Open
Abstract
Ecotin, first described in Escherichia coli, is a potent
inhibitor of a broad range of serine proteases including those typically
released by the innate immune system such as neutrophil elastase (NE). Here we
describe the identification of ecotin orthologs in various
Campylobacter species, including Campylobacter
rectus and Campylobacter showae residing in the
oral cavity and implicated in the development and progression of periodontal
disease in humans. To investigate the function of these ecotins in
vitro, the orthologs from C.
rectus and C. showae were
recombinantly expressed and purified from E.
coli. Using CmeA degradation/protection assays,
fluorescence resonance energy transfer and NE activity assays, we found that
ecotins from C. rectus and C.
showae inhibit NE, factor Xa and trypsin, but not the
Campylobacter jejuni serine protease HtrA or its ortholog
in E. coli, DegP. To further evaluate ecotin
function in vivo, an E. coli
ecotin-deficient mutant was complemented with the C.
rectus and C. showae
homologs. Using a neutrophil killing assay, we demonstrate that the low survival
rate of the E. coli ecotin-deficient mutant
can be rescued upon expression of ecotins from C.
rectus and C. showae. In
addition, the C. rectus and
C. showae ecotins partially compensate for
loss of N-glycosylation and increased protease susceptibility in the related
pathogen, Campylobacter jejuni, thus implicating a similar role
for these proteins in the native host to cope with the protease-rich environment
of the oral cavity.
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Affiliation(s)
- Cody Thomas
- Department of Microbiology and Complex Carbohydrate Research Center,
University of Georgia, Athens, Georgia, United States of
America
| | - Harald Nothaft
- Department of Biological Sciences, University of Alberta, Edmonton,
Alberta, Canada
| | - Ruchi Yadav
- Department of Infectious Diseases, University of Georgia, Athens,
Georgia, United States of America
| | - Christopher Fodor
- Department of Biological Sciences, University of Alberta, Edmonton,
Alberta, Canada
| | - Abofu Alemka
- Department of Biological Sciences, University of Alberta, Edmonton,
Alberta, Canada
| | - Oluwadamilola Oni
- Department of Infectious Diseases, University of Georgia, Athens,
Georgia, United States of America
| | - Michael Bell
- Department of Infectious Diseases, University of Georgia, Athens,
Georgia, United States of America
| | - Balázs Rada
- Department of Infectious Diseases, University of Georgia, Athens,
Georgia, United States of America
| | - Christine M. Szymanski
- Department of Microbiology and Complex Carbohydrate Research Center,
University of Georgia, Athens, Georgia, United States of
America
- Department of Biological Sciences, University of Alberta, Edmonton,
Alberta, Canada
- * E-mail:
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24
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Abstract
Neutrophils and eosinophils are granulocytes that have very distinct functions. Neutrophils are first responders to external threats, and they use different mechanisms to control pathogens. Phagocytosis, reactive oxygen species, and neutrophil extracellular traps (NETs) are some of the mechanisms that neutrophils utilize to fight pathogens. Although there is some controversy as to whether NETs are in fact beneficial or detrimental to the host, it mainly depends on the biological context. NETs can contribute to disease pathogenesis in certain types of diseases, while they are also undeniably critical components of the innate immune response. On the contrary, the role of eosinophils during host immune responses remains to be better elucidated. Eosinophils play an important role during helminthic infections and allergic responses. Eosinophils can function as effector cells in viral respiratory infections, gut bacterial infections, and as modulators of immune responses by driving the balance between Th1 and Th2 responses. In particular, eosinophils have biological activities that appear to be quite similar to those of neutrophils. Both possess bactericidal activity, can activate proinflammatory responses, can modulate adaptive immune responses, can form extracellular traps, and can be beneficial or detrimental to the host according to the underlying pathology. In this review we compare these two cell types with a focus on highlighting their numerous similarities related to extracellular traps.
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Affiliation(s)
- Tyler L. Williams
- Department of Microbiology and Immunology, Louisiana State University (LSU), Health Science Center, Shreveport, LA 71103, USA; (T.L.W.); (E.T.)
| | - Balázs Rada
- Department of Infectious Diseases, University of Georgia, Athens, GA 30302, USA;
| | - Eshaan Tandon
- Department of Microbiology and Immunology, Louisiana State University (LSU), Health Science Center, Shreveport, LA 71103, USA; (T.L.W.); (E.T.)
| | - Monica C. Gestal
- Department of Microbiology and Immunology, Louisiana State University (LSU), Health Science Center, Shreveport, LA 71103, USA; (T.L.W.); (E.T.)
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Yadav R, Linnemann RW, Kahlenberg JM, Bridges LS, Stecenko AA, Rada B. IgA autoantibodies directed against self DNA are elevated in cystic fibrosis and associated with more severe lung dysfunction. Autoimmunity 2020; 53:476-484. [PMID: 33258386 DOI: 10.1080/08916934.2020.1839890] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although extracellular host DNA (ecDNA) levels in CF airways were linked to airflow obstruction and recombinant DNAse therapy is beneficial for CF patients, it remains incompletely understood whether ecDNA also leads to an autoimmune response. Here we hypothesized that chronic presence of DNA in CF airways triggers the production of autoantibodies targeting host human DNA. We measured the levels of IgA autoantibodies recognising host double-stranded (ds) DNA in the blood and sputum samples of CF patients and only sera of controls subjects and patients suffering from rheumatoid arthritis and systemic lupus erythematosus (SLE) that served as non-CF, autoimmune disease cohorts. We found that concentrations of anti-dsDNA IgA, but not IgG, autoantibodies in the circulation were significantly elevated in adult CF patients compared to age-matched, control subjects. Systemic levels of anti-dsDNA IgA antibodies negatively correlated with FEV1% predicted, a measure of lung function, in CF patients. Anti-dsDNA IgA autoantibodies were also detected in CF sputa but sputum levels did not correlate with the degree of airway obstruction or sputum levels of DNA. We also found elevated autoantibody levels in CF children as 76.5% of CF patients younger than 10 years and 87.5% of CF patients 10-21 years had higher blood anti-dsDNA IgA levels than the highest value found in healthy control adults. Overall, our results detect elevated systemic anti-dsDNA IgA autoantibody levels in CF adults, teenagers and young children. We speculate that the appearance of an autoimmune response against host DNA in CF is an early event potentially contributing to disease pathogenesis. Highlights CF serum contains elevated levels of anti-dsDNA IgA, but not anti-dsDNA IgG, autoantibodies Anti-dsDNA IgA autoantibody levels in serum correlate with airflow obstruction in CF Anti-dsDNA IgA autoantibodies are detected in CF sputum but do not correlate with airflow obstruction Anti-dsDNA IgA autoantibodies are also elevated in the blood of the majority of CF toddlers and youth.
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Affiliation(s)
- Ruchi Yadav
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
| | - Rachel W Linnemann
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Joanne Michelle Kahlenberg
- Division of Rheumatology, Department of Internal Medicine, School of Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Louis S Bridges
- Division of Clinical Immunology and Rheumatology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Arlene A Stecenko
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
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Almutairi F, Lee JK, Rada B. Regulator of G protein signaling 10: Structure, expression and functions in cellular physiology and diseases. Cell Signal 2020; 75:109765. [PMID: 32882407 PMCID: PMC7579743 DOI: 10.1016/j.cellsig.2020.109765] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/26/2020] [Accepted: 08/27/2020] [Indexed: 01/22/2023]
Abstract
Regulator of G protein signaling 10 (RGS10) belongs to the superfamily of RGS proteins, defined by the presence of a conserved RGS domain that canonically binds and deactivates heterotrimeric G-proteins. RGS proteins act as GTPase activating proteins (GAPs), which accelerate GTP hydrolysis on the G-protein α subunits and result in termination of signaling pathways downstream of G protein-coupled receptors. RGS10 is the smallest protein of the D/R12 subfamily and selectively interacts with Gαi proteins. It is widely expressed in many cells and tissues, with the highest expression found in the brain and immune cells. RGS10 expression is transcriptionally regulated via epigenetic mechanisms. Although RGS10 lacks multiple of the defined regulatory domains found in other RGS proteins, RGS10 contains post-translational modification sites regulating its expression, localization, and function. Additionally, RGS10 is a critical protein in the regulation of physiological processes in multiple cells, where dysregulation of its expression has been implicated in various diseases including Parkinson's disease, multiple sclerosis, osteopetrosis, chemoresistant ovarian cancer and cardiac hypertrophy. This review summarizes RGS10 features and its regulatory mechanisms, and discusses the known functions of RGS10 in cellular physiology and pathogenesis of several diseases.
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Affiliation(s)
- Faris Almutairi
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA, USA; Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Jae-Kyung Lee
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
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Gingerich AD, Doja F, Thomason R, Tóth E, Bradshaw JL, Douglass MV, McDaniel LS, Rada B. Oxidative killing of encapsulated and nonencapsulated Streptococcus pneumoniae by lactoperoxidase-generated hypothiocyanite. PLoS One 2020; 15:e0236389. [PMID: 32730276 PMCID: PMC7392276 DOI: 10.1371/journal.pone.0236389] [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: 08/22/2019] [Accepted: 07/06/2020] [Indexed: 01/04/2023] Open
Abstract
Streptococcus pneumoniae (Pneumococcus) infections affect millions of people worldwide, cause serious mortality and represent a major economic burden. Despite recent successes due to pneumococcal vaccination and antibiotic use, Pneumococcus remains a significant medical problem. Airway epithelial cells, the primary responders to pneumococcal infection, orchestrate an extracellular antimicrobial system consisting of lactoperoxidase (LPO), thiocyanate anion and hydrogen peroxide (H2O2). LPO oxidizes thiocyanate using H2O2 into the final product hypothiocyanite that has antimicrobial effects against a wide range of microorganisms. However, hypothiocyanite’s effect on Pneumococcus has never been studied. Our aim was to determine whether hypothiocyanite can kill S. pneumoniae. Bactericidal activity was measured in a cell-free in vitro system by determining the number of surviving pneumococci via colony forming units on agar plates, while bacteriostatic activity was assessed by measuring optical density of bacteria in liquid cultures. Our results indicate that hypothiocyanite generated by LPO exerted robust killing of both encapsulated and nonencapsulated pneumococcal strains. Killing of S. pneumoniae by a commercially available hypothiocyanite-generating product was even more pronounced than that achieved with laboratory reagents. Catalase, an H2O2 scavenger, inhibited killing of pneumococcal by hypothiocyanite under all circumstances. Furthermore, the presence of the bacterial capsule or lytA-dependent autolysis had no effect on hypothiocyanite-mediated killing of pneumococci. On the contrary, a pneumococcal mutant deficient in pyruvate oxidase (main bacterial H2O2 source) had enhanced susceptibility to hypothiocyanite compared to its wild-type strain. Overall, results shown here indicate that numerous pneumococcal strains are susceptible to LPO-generated hypothiocyanite.
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Affiliation(s)
- Aaron D. Gingerich
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, United States of America
| | - Fayhaa Doja
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, United States of America
| | - Rachel Thomason
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, United States of America
| | - Eszter Tóth
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, United States of America
| | - Jessica L. Bradshaw
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Martin V. Douglass
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, United States of America
| | - Larry S. McDaniel
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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Cyr JL, Gawriluk TR, Kimani JM, Rada B, Watford WT, Kiama SG, Seifert AW, Ezenwa VO. Regeneration-Competent and -Incompetent Murids Differ in Neutrophil Quantity and Function. Integr Comp Biol 2020; 59:1138-1149. [PMID: 30989211 DOI: 10.1093/icb/icz023] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Regeneration is rare in mammals, but spiny mice (Acomys spp.) naturally regenerate skin and ear holes. Inflammation is thought to inhibit regeneration during wound healing, but aspects of inflammation contribute to both regeneration and pathogen defense. We compared neutrophil traits among uninjured, regeneration-competent (Acomys: A. cahirinus, A. kempi, A. percivali) and -incompetent (Mus musculus: Swiss Webster, wild-caught strains) murids to test for constitutive differences in neutrophil quantity and function between these groups. Neutrophil quantity differed significantly among species. In blood, Acomys had lower percentages of circulating neutrophils than Mus; and in bone marrow, Acomys had higher percentages of band neutrophils and lower percentages of segmented neutrophils. Functionally, Acomys and Mus neutrophils did not differ in their ability to migrate or produce reactive oxygen species, but Acomys neutrophils phagocytosed more fungal zymosan. Despite this enhanced phagocytosis activity, Acomys neutrophils were not more effective than Mus neutrophils at killing Escherichia coli. Interestingly, whole blood bacteria killing was dominated by serum in Acomys versus neutrophils only or neutrophils and serum in Mus, suggesting that Acomys primarily rely on serum to kill bacteria whereas Mus do not. These subtle differences in neutrophil traits may allow regeneration-competent species to offset damaging effects of inflammation without compromising pathogen defense.
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Affiliation(s)
- Jennifer L Cyr
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Thomas R Gawriluk
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA
| | - John M Kimani
- Department of Veterinary Anatomy and Physiology, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Wendy T Watford
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Stephen G Kiama
- Department of Veterinary Anatomy and Physiology, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
| | - Ashley W Seifert
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA.,Department of Veterinary Anatomy and Physiology, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
| | - Vanessa O Ezenwa
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.,Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
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Yadav R, Yoo DG, Kahlenberg JM, Bridges SL, Oni O, Huang H, Stecenko A, Rada B. Systemic levels of anti-PAD4 autoantibodies correlate with airway obstruction in cystic fibrosis. J Cyst Fibros 2019; 18:636-645. [PMID: 30638826 PMCID: PMC6620172 DOI: 10.1016/j.jcf.2018.12.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [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: 07/13/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 12/15/2022]
Abstract
Cystic fibrosis (CF) airway disease is characterized by the long-term presence of neutrophil granulocytes. Formation of neutrophil extracellular traps (NETs) and/or autoantibodies directed against extracellular components of NETs are possible contributors to neutrophil-mediated lung damage in CF. The goal of this study was to measure their levels in CF adults compared to healthy controls and subjects with rheumatologic diseases known to develop NET-related autoantibodies and pathologies, rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Sera were analyzed from the following number of subjects: 37 CF, 23 healthy controls (HC), 20 RA, and 21 SLE. CF had elevated serum myeloperoxidase (MPO) concentrations (347.5±56.1 ng/ml, mean+/-S.E.M., p = .0132) compared to HC (144.5±14.6 ng/ml) but not of neutrophil elastase (NE) complexed with alpha-1-antitrypsin, cell-free DNA or NE-DNA complexes. The peptidylarginine deiminase 4 (PAD4) enzyme is required for NET formation and associated DNA release in neutrophils. Serum levels of anti-PAD4 antibodies (Ab) were elevated in CF (p = .0147) compared to HC and showed an inverse correlation with a measure of lung function, FEV1% predicted (r = -0.5020, p = .015), as did MPO levels (r = -0.4801, p = .0026). Anti-PAD4 Ab levels in CF sera associated with lung infection by P. aeruginosa, but not that by S. aureus, age, sex, CF-related diabetes or the presence of musculoskeletal pain. Serum levels of anti-citrullinated protein Abs (ACPAs) and anti-nucleosome Abs were not elevated in CF compared to HC (p = .7498, p = .0678). In summary, adult CF subjects develop an autoimmune response against NET components that correlates with worsening lung disease.
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Affiliation(s)
- Ruchi Yadav
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
| | - Dae-Goon Yoo
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
| | - J Michelle Kahlenberg
- Division of Rheumatology, University of Michigan, School of Medicine, Ann Arbor, MI, USA
| | - S Louis Bridges
- Division of Clinical Immunology and Rheumatology, University of Alabama at Birmingham, School of Medicine, Birmingham, AL, USA
| | - Oluwadamilola Oni
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA
| | - Hanwen Huang
- Department of Epidemiology & Biostatistics, College of Public Health, The University of Georgia, Athens, GA, USA
| | - Arlene Stecenko
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, GA, USA.
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Patel U, Gingerich A, Widman L, Sarr D, Tripp RA, Rada B. Susceptibility of influenza viruses to hypothiocyanite and hypoiodite produced by lactoperoxidase in a cell-free system. PLoS One 2018; 13:e0199167. [PMID: 30044776 PMCID: PMC6059396 DOI: 10.1371/journal.pone.0199167] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [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: 01/03/2018] [Accepted: 06/01/2018] [Indexed: 12/03/2022] Open
Abstract
Lactoperoxidase (LPO) is an enzyme found in several exocrine secretions including the airway surface liquid producing antimicrobial substances from mainly halide and pseudohalide substrates. Although the innate immune function of LPO has been documented against several microbes, a detailed characterization of its mechanism of action against influenza viruses is still missing. Our aim was to study the antiviral effect and substrate specificity of LPO to inactivate influenza viruses using a cell-free experimental system. Inactivation of different influenza virus strains was measured in vitro system containing LPO, its substrates, thiocyanate (SCN-) or iodide (I-), and the hydrogen peroxide (H2O2)-producing system, glucose and glucose oxidase (GO). Physiologically relevant concentrations of the components of the LPO/H2O2/(SCN-/I-) antimicrobial system were exposed to twelve different strains of influenza A and B viruses in vitro and viral inactivation was assessed by determining plaque-forming units of non-inactivated viruses using Madin-Darby canine kidney cells (MDCK) cells. Our data show that LPO is capable of inactivating all influenza virus strains tested: H1N1, H1N2 and H3N2 influenza A viruses (IAV) and influenza B viruses (IBV) of both, Yamagata and Victoria lineages. The extent of viral inactivation, however, varied among the strains and was in part dependent on the LPO substrate. Inactivation of H1N1 and H1N2 viruses by LPO showed no substrate preference, whereas H3N2 influenza strains were inactivated significantly more efficiently when iodide, not thiocyanate, was the LPO substrate. Although LPO-mediated inactivation of the influenza B strains tested was strain-dependent, it showed slight preference towards thiocyanate as the substrate. The results presented here show that the LPO/H2O2/(SCN-/I-) cell-free, in vitro experimental system is a functional tool to study the specificity, efficiency and the molecular mechanism of action of influenza inactivation by LPO. These studies tested the hypothesis that influenza strains are all susceptible to the LPO-based antiviral system but exhibit differences in their substrate specificities. We propose that a LPO-based antiviral system is an important contributor to anti-influenza virus defense of the airways.
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Affiliation(s)
- Urmi Patel
- University of Georgia, College of Veterinary Medicine, Department of Infectious Diseases, Athens, Georgia, United States of America
| | - Aaron Gingerich
- University of Georgia, College of Veterinary Medicine, Department of Infectious Diseases, Athens, Georgia, United States of America
| | - Lauren Widman
- University of Georgia, College of Veterinary Medicine, Department of Infectious Diseases, Athens, Georgia, United States of America
| | - Demba Sarr
- University of Georgia, College of Veterinary Medicine, Department of Infectious Diseases, Athens, Georgia, United States of America
| | - Ralph A. Tripp
- University of Georgia, College of Veterinary Medicine, Department of Infectious Diseases, Athens, Georgia, United States of America
| | - Balázs Rada
- University of Georgia, College of Veterinary Medicine, Department of Infectious Diseases, Athens, Georgia, United States of America
- * E-mail:
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31
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Rada B, Floyd M, Winn M, Chassaing B, Gewirtz A, Goldberg J, McCarter L. 72 Neutrophil extracellular trap formation triggered by Pseudomonas aeruginosa: relevance to cystic fibrosis lung disease. J Cyst Fibros 2017. [DOI: 10.1016/s1569-1993(17)30436-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Acuff NV, Li X, Elmore J, Rada B, Watford WT. Tpl2 promotes neutrophil trafficking, oxidative burst, and bacterial killing. J Leukoc Biol 2017; 101:1325-1333. [PMID: 28356348 DOI: 10.1189/jlb.3a0316-146r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 02/03/2017] [Accepted: 03/06/2017] [Indexed: 12/17/2022] Open
Abstract
Tumor progression locus 2 (Tpl2) is a serine/threonine kinase that promotes inflammatory cytokine production by activating the MEK/ERK pathway. Tpl2 has been shown to be important for eliciting the inflammatory properties of macrophages; however, there is relatively little known about the contribution of Tpl2 to neutrophil effector functions. This is an important consideration, as neutrophils provide the first line of defense against infection in the innate immune system. We found that Tpl2 is expressed in both human and murine neutrophils, suggesting a potential function for Tpl2 in this lineage. Despite significantly higher proportions of bone marrow (BM) neutrophils in Tpl2-deficient (Tpl2-/- ) mice compared with wild-type (WT) mice, Tpl2-/- mice have significantly reduced proportions of circulating neutrophils. Tpl2-/- neutrophils show impaired recruitment to thioglycollate, which was primarily a result of neutrophil-extrinsic factors in the host. In response to infection, neutrophils secrete inflammatory cytokines and produce reactive oxygen species (ROS), which promote bacterial killing. Tpl2 ablation impaired neutrophil TNF secretion in response to LPS stimulation, superoxide generation in response to the chemotactic peptide fMLP, and killing of the extracellular bacterium, Citrobacter rodentium, despite normal bacterial phagocytosis. These results implicate Tpl2 in the regulation of multiple neutrophil antimicrobial pathways, including inflammatory cytokine secretion and oxidative burst. Furthermore, they indicate that Tpl2 functions early during infection to bolster neutrophil-mediated innate immunity against extracellular bacteria.
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Affiliation(s)
- Nicole V Acuff
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Xin Li
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Jessica Elmore
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Balázs Rada
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Wendy T Watford
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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McCoy CJ, Reaves BJ, Giguère S, Coates R, Rada B, Wolstenholme AJ. Human Leukocytes Kill Brugia malayi Microfilariae Independently of DNA-Based Extracellular Trap Release. PLoS Negl Trop Dis 2017; 11:e0005279. [PMID: 28045905 PMCID: PMC5234842 DOI: 10.1371/journal.pntd.0005279] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [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: 07/11/2016] [Revised: 01/13/2017] [Accepted: 12/21/2016] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Wuchereria bancrofti, Brugia malayi and Brugia timori infect over 100 million people worldwide and are the causative agents of lymphatic filariasis. Some parasite carriers are amicrofilaremic whilst others facilitate mosquito-based disease transmission through blood-circulating microfilariae (Mf). Recent findings, obtained largely from animal model systems, suggest that polymorphonuclear leukocytes (PMNs) contribute to parasitic nematode-directed type 2 immune responses. When exposed to certain pathogens PMNs release extracellular traps (NETs) in the form of chromatin loaded with various antimicrobial molecules and proteases. PRINCIPAL FINDINGS In vitro, PMNs expel large amounts of NETs that capture but do not kill B. malayi Mf. NET morphology was confirmed by fluorescence imaging of worm-NET aggregates labelled with DAPI and antibodies to human neutrophil elastase, myeloperoxidase and citrullinated histone H4. A fluorescent, extracellular DNA release assay was used to quantify and observe Mf induced NETosis over time. Blinded video analyses of PMN-to-worm attachment and worm survival during Mf-leukocyte co-culture demonstrated that DNase treatment eliminates PMN attachment in the absence of serum, autologous serum bolsters both PMN attachment and PMN plus peripheral blood mononuclear cell (PBMC) mediated Mf killing, and serum heat inactivation inhibits both PMN attachment and Mf killing. Despite the effects of heat inactivation, the complement inhibitor compstatin did not impede Mf killing and had little effect on PMN attachment. Both human PMNs and monocytes, but not lymphocytes, are able to kill B. malayi Mf in vitro and NETosis does not significantly contribute to this killing. Leukocytes derived from presumably parasite-naïve U.S. resident donors vary in their ability to kill Mf in vitro, which may reflect the pathological heterogeneity associated with filarial parasitic infections. CONCLUSIONS/SIGNIFICANCE Human innate immune cells are able to recognize, attach to and kill B. malayi microfilariae in an in vitro system. This suggests that, in vivo, the parasites can evade this ability, or that only some human hosts support an infection with circulating Mf.
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Affiliation(s)
- Ciaran J. McCoy
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States of America
| | - Barbara J. Reaves
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States of America
| | - Steeve Giguère
- Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
| | - Ruby Coates
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States of America
- Department of Biology & Biochemistry, University of Bath, Bath, United Kingdom
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
| | - Adrian J. Wolstenholme
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States of America
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Sil P, Hayes CP, Reaves BJ, Breen P, Quinn S, Sokolove J, Rada B. P2Y6 Receptor Antagonist MRS2578 Inhibits Neutrophil Activation and Aggregated Neutrophil Extracellular Trap Formation Induced by Gout-Associated Monosodium Urate Crystals. J Immunol 2016; 198:428-442. [PMID: 27903742 DOI: 10.4049/jimmunol.1600766] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 10/23/2016] [Indexed: 12/27/2022]
Abstract
Human neutrophils (polymorphonuclear leukocytes [PMNs]) generate inflammatory responses within the joints of gout patients upon encountering monosodium urate (MSU) crystals. Neutrophil extracellular traps (NETs) are found abundantly in the synovial fluid of gout patients. The detailed mechanism of MSU crystal-induced NET formation remains unknown. Our goal was to shed light on possible roles of purinergic signaling and neutrophil migration in mediating NET formation induced by MSU crystals. Interaction of human neutrophils with MSU crystals was evaluated by high-throughput live imaging using confocal microscopy. We quantitated NET levels in gout synovial fluid supernatants and detected enzymatically active neutrophil primary granule enzymes, myeloperoxidase, and human neutrophil elastase. Suramin and PPADS, general P2Y receptor blockers, and MRS2578, an inhibitor of the purinergic P2Y6 receptor, blocked NET formation triggered by MSU crystals. AR-C25118925XX (P2Y2 antagonist) did not inhibit MSU crystal-stimulated NET release. Live imaging of PMNs showed that MRS2578 represses neutrophil migration and blocked characteristic formation of MSU crystal-NET aggregates called aggregated NETs. Interestingly, the store-operated calcium entry channel inhibitor (SK&F96365) also reduced MSU crystal-induced NET release. Our results indicate that the P2Y6/store-operated calcium entry/IL-8 axis is involved in MSU crystal-induced aggregated NET formation, but MRS2578 could have additional effects affecting PMN migration. The work presented in the present study could lead to a better understanding of gouty joint inflammation and help improve the treatment and care of gout patients.
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Affiliation(s)
- Payel Sil
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602
| | - Craig P Hayes
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602
| | - Barbara J Reaves
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602
| | - Patrick Breen
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602
| | - Shannon Quinn
- Department of Computer Science, Franklin College of Arts and Sciences, University of Georgia, Athens, 30602 GA
| | - Jeremy Sokolove
- Stanford University School of Medicine, Stanford, CA 94305; and.,Internal Medicine and Rheumatology, VA Palo Alto Health Care System, Palo Alto, CA 94034
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602;
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Floyd M, Winn M, Cullen C, Sil P, Chassaing B, Yoo DG, Gewirtz AT, Goldberg JB, McCarter LL, Rada B. Swimming Motility Mediates the Formation of Neutrophil Extracellular Traps Induced by Flagellated Pseudomonas aeruginosa. PLoS Pathog 2016; 12:e1005987. [PMID: 27855208 PMCID: PMC5113990 DOI: 10.1371/journal.ppat.1005987] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [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: 01/19/2016] [Accepted: 10/10/2016] [Indexed: 12/11/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen causing severe infections often characterized by robust neutrophilic infiltration. Neutrophils provide the first line of defense against P. aeruginosa. Aside from their defense conferred by phagocytic activity, neutrophils also release neutrophil extracellular traps (NETs) to immobilize bacteria. Although NET formation is an important antimicrobial process, the details of its mechanism are largely unknown. The identity of the main components of P. aeruginosa responsible for triggering NET formation is unclear. In this study, our focus was to identify the main bacterial factors mediating NET formation and to gain insight into the underlying mechanism. We found that P. aeruginosa in its exponential growth phase promoted strong NET formation in human neutrophils while its NET-inducing ability dramatically decreased at later stages of bacterial growth. We identified the flagellum as the primary component of P. aeruginosa responsible for inducing NET extrusion as flagellum-deficient bacteria remained seriously impaired in triggering NET formation. Purified P. aeruginosa flagellin, the monomeric component of the flagellum, does not stimulate NET formation in human neutrophils. P. aeruginosa-induced NET formation is independent of the flagellum-sensing receptors TLR5 and NLRC4 in both human and mouse neutrophils. Interestingly, we found that flagellar motility, not flagellum binding to neutrophils per se, mediates NET release induced by flagellated bacteria. Immotile, flagellar motor-deficient bacterial strains producing paralyzed flagella did not induce NET formation. Forced contact between immotile P. aeruginosa and neutrophils restored their NET-inducing ability. Both the motAB and motCD genetic loci encoding flagellar motor genes contribute to maximal NET release; however the motCD genes play a more important role. Phagocytosis of P. aeruginosa and superoxide production by neutrophils were also largely dependent upon a functional flagellum. Taken together, the flagellum is herein presented for the first time as the main organelle of planktonic bacteria responsible for mediating NET release. Furthermore, flagellar motility, rather than binding of the flagellum to flagellum-sensing receptors on host cells, is required for P. aeruginosa to induce NET release.
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Affiliation(s)
- Madison Floyd
- College of Veterinary Medicine, Department of Infectious Diseases, The University of Georgia, Athens, Georgia, United States of America
| | - Matthew Winn
- College of Veterinary Medicine, Department of Infectious Diseases, The University of Georgia, Athens, Georgia, United States of America
| | - Christian Cullen
- College of Veterinary Medicine, Department of Infectious Diseases, The University of Georgia, Athens, Georgia, United States of America
| | - Payel Sil
- College of Veterinary Medicine, Department of Infectious Diseases, The University of Georgia, Athens, Georgia, United States of America
| | - Benoit Chassaing
- Center for Inflammation, Immunity, & Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia, United States of America
| | - Dae-goon Yoo
- College of Veterinary Medicine, Department of Infectious Diseases, The University of Georgia, Athens, Georgia, United States of America
| | - Andrew T. Gewirtz
- Center for Inflammation, Immunity, & Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia, United States of America
| | - Joanna B. Goldberg
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Linda L. McCarter
- Carver College of Medicine, Department of Microbiology, The University of Iowa, Iowa City, Iowa, United States of America
| | - Balázs Rada
- College of Veterinary Medicine, Department of Infectious Diseases, The University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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Sil P, Wicklum H, Surell C, Rada B. Macrophage-derived IL-1β enhances monosodium urate crystal-triggered NET formation. Inflamm Res 2016; 66:227-237. [PMID: 27853847 DOI: 10.1007/s00011-016-1008-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [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: 07/30/2016] [Revised: 11/01/2016] [Accepted: 11/09/2016] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE AND DESIGN Arthritic gout is caused by joint inflammation triggered by the damaging effects of monosodium uric acid (MSU) crystal accumulation in the synovial space. Neutrophils play a major role in mediating joint inflammation in gout. Along with neutrophils, other immune cells, such as macrophages, are present in inflamed joints and contribute to gout pathogenesis. Neutrophils form neutrophil extracellular traps (NETs) in response to MSU crystals. In the presence of MSU crystals, macrophages release IL-1β, a cytokine crucial to initiate gout pathogenesis and neutrophil recruitment. Our research investigated interactions between human macrophages and neutrophils in an in vitro model system and asked how macrophages affect NET formation stimulated by MSU crystals. MATERIALS OR SUBJECTS Human neutrophils and PBMCs were isolated from peripheral blood of healthy volunteers. PBMCs were differentiated into macrophages in vitro using human M-CSF. TREATMENT Human neutrophils were pretreated with macrophage-conditioned media, neutrophil-conditioned media, recombinant human IL-1β or anakinra prior to stimulation by MSU crystals. METHOD Interaction of neutrophils with MSU crystals was evaluated by live imaging using confocal microscopy. The presence of myeloperoxidase (MPO) and neutrophil elastase (NE) was measured by ELISA. NET formation was quantitated by Sytox Orange-based extracellular DNA release assay and NE-DNA ELISA. AggNET formation was assessed by macroscopic evaluation. RESULTS We found that crystal- and cell-free supernatants of macrophages stimulated with MSU crystals promote MSU crystal-stimulated NET formation in human neutrophils. This observation was confirmed by additional assays measuring the release of MPO, NE, and the enzymatic activity of NE. MSU crystal-induced NET formation remained unchanged when neutrophil supernatants were tested. IL-1β is a crucial cytokine orchestrating the onset of inflammation in gout and is known to be released in large amounts from macrophages following MSU crystal stimulation. We found that recombinant IL-1β strongly promoted MSU crystal-induced NET formation in human neutrophils. Interestingly, IL-1β alone did not induce any NET release. We also found that clinical grade anakinra, an IL-1 receptor blocker, strongly reduced the NETosis-enhancing effect of macrophage supernatants indicating that IL-1β is mainly responsible for this effect. CONCLUSIONS Macrophage-derived IL-1β enhances MSU crystal-induced NET release in neutrophils. We identified a new mechanism by which macrophages and IL-1β affect neutrophil functions, and could contribute to the inflammatory conditions present in gout. Our results also revealed a new anti-inflammatory mechanism of anakinra.
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Affiliation(s)
- Payel Sil
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, 501 D.W. Brooks Drive, Athens, GA, 30602, USA
| | - Haley Wicklum
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, 501 D.W. Brooks Drive, Athens, GA, 30602, USA
| | - Chandler Surell
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, 501 D.W. Brooks Drive, Athens, GA, 30602, USA
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, 501 D.W. Brooks Drive, Athens, GA, 30602, USA.
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Gingerich A, Pang L, Hanson J, Dlugolenski D, Streich R, Lafontaine ER, Nagy T, Tripp RA, Rada B. Hypothiocyanite produced by human and rat respiratory epithelial cells inactivates extracellular H1N2 influenza A virus. Inflamm Res 2016; 65:71-80. [PMID: 26608498 PMCID: PMC10483388 DOI: 10.1007/s00011-015-0892-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [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: 07/08/2015] [Revised: 09/22/2015] [Accepted: 10/27/2015] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE AND DESIGN Our aim was to study whether an extracellular, oxidative antimicrobial mechanism inherent to tracheal epithelial cells is capable of inactivating influenza H1N2 virus. MATERIAL OR SUBJECTS Epithelial cells were isolated from tracheas of male Sprague-Dawley rats. Both primary human and rat tracheobronchial epithelial cells were differentiated in air-liquid interface cultures. TREATMENT A/swine/Illinois/02860/09 (swH1N2) influenza A virions were added to the apical side of airway cells for 1 h in the presence or absence of lactoperoxidase or thiocyanate. METHODS Characterization of rat epithelial cells (morphology, Duox expression) occurred via western blotting, PCR, hydrogen peroxide production measurement and histology. The number of viable virions was determined by plaque assays. Statistical difference of the results was analyzed by ANOVA and Tukey's test. RESULTS Our data show that rat tracheobronchial epithelial cells develop a differentiated, polarized monolayer with high transepithelial electrical resistance, mucin production and expression of dual oxidases. Influenza A virions are inactivated by human and rat epithelial cells via a dual oxidase-, lactoperoxidase- and thiocyanate-dependent mechanism. CONCLUSIONS Differentiated air-liquid interface cultures of rat tracheal epithelial cells provide a novel model to study airway epithelium-influenza interactions. The dual oxidase/lactoperoxidase/thiocyanate extracellular oxidative system producing hypothiocyanite is a fast and potent anti-influenza mechanism inactivating H1N2 viruses prior to infection of the epithelium.
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Affiliation(s)
- Aaron Gingerich
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, 501 D.W. Brooks Drive, Athens, GA, 30602, USA
| | - Lan Pang
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, 501 D.W. Brooks Drive, Athens, GA, 30602, USA
| | - Jarod Hanson
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, 501 D.W. Brooks Drive, Athens, GA, 30602, USA
| | - Daniel Dlugolenski
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, 501 D.W. Brooks Drive, Athens, GA, 30602, USA
| | - Rebecca Streich
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, 501 D.W. Brooks Drive, Athens, GA, 30602, USA
| | - Eric R Lafontaine
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, 501 D.W. Brooks Drive, Athens, GA, 30602, USA
| | - Tamás Nagy
- Department of Pathology, College of Veterinary Medicine, University of Georgia, 501 D.W. Brooks Drive, Athens, GA, 30602, USA
| | - Ralph A Tripp
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, 501 D.W. Brooks Drive, Athens, GA, 30602, USA
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, 501 D.W. Brooks Drive, Athens, GA, 30602, USA.
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Kuriakose T, Rada B, Watford WT. Tumor progression locus 2-dependent oxidative burst drives phosphorylation of extracellular signal-regulated kinase during TLR3 and 9 signaling. J Biol Chem 2014; 289:36089-100. [PMID: 25378393 DOI: 10.1074/jbc.m114.587121] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Signal transduction via NFκB and MAP kinase cascades is a universal response initiated upon pathogen recognition by Toll-like receptors (TLRs). How activation of these divergent signaling pathways is integrated to dictate distinct immune responses to diverse pathogens is still incompletely understood. Herein, contrary to current perception, we demonstrate that a signaling pathway defined by the inhibitor of κB kinase β (IKKβ), MAP3 kinase tumor progression locus 2 (Tpl2/MAP3K8), and MAP kinase ERK is differentially activated by TLRs. TLRs 2, 4, and 7 directly activate this inflammatory axis, inducing immediate ERK phosphorylation and early TNFα secretion. In addition to TLR adaptor proteins, IKKβ-Tpl2-ERK activation by TLR4 is regulated by the TLR4 co-receptor CD14 and the tyrosine kinase Syk. Signals from TLRs 3 and 9 do not initiate early activation of IKKβ-Tpl2-ERK pathway but instead induce delayed, NADPH-oxidase-dependent ERK phosphorylation and TNFα secretion via autocrine reactive oxygen species signaling. Unexpectedly, Tpl2 is an essential regulator of ROS production during TLR signaling. Overall, our study reveals distinct mechanisms activating a common inflammatory signaling cascade and delineates differences in MyD88-dependent signaling between endosomal TLRs 7 and 9. These findings further confirm the importance of Tpl2 in innate host defense mechanisms and also enhance our understanding of how the immune system tailors pathogen-specific gene expression patterns.
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Affiliation(s)
- Teneema Kuriakose
- From the Department of Infectious Diseases, The University of Georgia, College of Veterinary Medicine, Athens, Georgia 30602
| | - Balázs Rada
- From the Department of Infectious Diseases, The University of Georgia, College of Veterinary Medicine, Athens, Georgia 30602
| | - Wendy T Watford
- From the Department of Infectious Diseases, The University of Georgia, College of Veterinary Medicine, Athens, Georgia 30602
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Rada B, Park JJ, Sil P, Geiszt M, Leto TL. NLRP3 inflammasome activation and interleukin-1β release in macrophages require calcium but are independent of calcium-activated NADPH oxidases. Inflamm Res 2014; 63:821-30. [PMID: 25048991 DOI: 10.1007/s00011-014-0756-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 06/18/2014] [Accepted: 07/02/2014] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE AND DESIGN We studied the involvement of calcium and calcium-activated NADPH oxidases in NLRP3 inflammasome activation and IL-1β release to better understand inflammasome signaling in macrophages. MATERIAL OR SUBJECTS Human volunteer blood donors were recruited to isolate monocytes to differentiate them into macrophages. Wild-type or DUOX1-deficient C57/B6 mice were used to prepare bone marrow-derived macrophages. TREATMENT Murine or human macrophages were treated in vitro with NLRP3 inflammasome agonists (ATP, silica crystals) or calcium agonists (thapsigargin, ionomycin) in calcium-containing or calcium-free medium. METHODS Intracellular calcium changes were followed by measuring FURA2-based fluorescence. Gene expression changes were measured by quantitative real-time PCR. Protein expression was assessed by western blotting. Enzymatic activity was measured by fluorescence caspase-1 activity assay. IL-1β release was determined by ELISA. ELISA data were analyzed by ANOVA and Tukey's post hoc test. RESULTS Our data show that calcium is essential for IL-1β release in human macrophages. Increases in cytosolic calcium alone lead to IL-1β secretion. Calcium removal blocks caspase-1 activation. Human macrophages express Duox1, a calcium-regulated NADPH oxidase that produces reactive oxygen species. However, Duox1-deficient murine macrophages show normal IL-1β release. CONCLUSIONS Human macrophage inflammasome activation and IL-1β secretion requires calcium but does not involve NADPH oxidases.
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Affiliation(s)
- Balázs Rada
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12441 Parklawn Drive, Rockville, MD, 20852, USA,
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Rada B, Boudreau HE, Park JJ, Leto TL. Histamine stimulates hydrogen peroxide production by bronchial epithelial cells via histamine H1 receptor and dual oxidase. Am J Respir Cell Mol Biol 2014; 50:125-34. [PMID: 23962049 DOI: 10.1165/rcmb.2013-0254oc] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Oxidative stress has been implicated in the pathogenesis of bronchial asthma. Besides granulocytes, the airway epithelium can produce large amounts of reactive oxygen species and can contribute to asthma-related oxidative stress. Histamine is a major inflammatory mediator present in large quantities in asthmatic airways. Whether histamine triggers epithelium-derived oxidative stress is unknown. We therefore aimed at characterizing human airway epithelial H2O2 production stimulated by histamine. We found that air-liquid interface cultures of primary human bronchial epithelial cells (BECs) and an immortalized BEC model (Cdk4/hTERT HBEC) produce H2O2 in response to histamine. The main source of airway epithelial H2O2 is an NADPH dual oxidase, Duox1. Out of the four histamine receptors (H1R-H4R), H1R has the highest expression in BECs and mediates the H2O2-producing effects of histamine. IL-4 induces Duox1 gene and protein expression levels and enhances histamine-induced H2O2 production by epithelial cells. Using HEK-293 cells expressing Duox1 or Duox2 and endogenous H1R, histamine triggers an immediate intracellular calcium signal and H2O2 release. Overexpression of H1R further increases the oxidative output of Duox-expressing HEK-293 cells. Our observations show that BECs respond to histamine with Duox-mediated H2O2 production. These findings reveal a mechanism that could be an important contributor to oxidative stress characteristic of asthmatic airways, suggesting novel therapeutic targets for treating asthmatic airway disease.
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Affiliation(s)
- Balázs Rada
- 1 Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia; and
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Yoo DG, Winn M, Pang L, Moskowitz SM, Malech HL, Leto TL, Rada B. Release of cystic fibrosis airway inflammatory markers from Pseudomonas aeruginosa-stimulated human neutrophils involves NADPH oxidase-dependent extracellular DNA trap formation. J Immunol 2014; 192:4728-38. [PMID: 24740504 DOI: 10.4049/jimmunol.1301589] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cystic fibrosis (CF) airways are characterized by bacterial infections, excess mucus production, and robust neutrophil recruitment. The main CF airway pathogen is Pseudomonas aeruginosa. Neutrophils are not capable of clearing the infection. Neutrophil primary granule components, myeloperoxidase (MPO) and human neutrophil elastase (HNE), are inflammatory markers in CF airways, and their increased levels are associated with poor lung function. Identifying the mechanism of MPO and HNE release from neutrophils is of high clinical relevance for CF. In this article, we show that human neutrophils release large amounts of neutrophil extracellular traps (NETs) in the presence of P. aeruginosa. Bacteria are entangled in NETs and colocalize with extracellular DNA. MPO, HNE, and citrullinated histone H4 are all associated with DNA in Pseudomonas-triggered NETs. Both laboratory standard strains and CF isolates of P. aeruginosa induce DNA, MPO, and HNE release from human neutrophils. The increase in peroxidase activity of neutrophil supernatants after Pseudomonas exposure indicates that enzymatically active MPO is released. P. aeruginosa induces a robust respiratory burst in neutrophils that is required for extracellular DNA release. Inhibition of the cytoskeleton prevents Pseudomonas-initiated superoxide production and DNA release. NADPH oxidase inhibition suppresses Pseudomonas-induced release of active MPO and HNE. Blocking MEK/ERK signaling results in only minimal inhibition of DNA release induced by Pseudomonas. Our data describe in vitro details of DNA, MPO, and HNE release from neutrophils activated by P. aeruginosa. We propose that Pseudomonas-induced NET formation is an important mechanism contributing to inflammatory conditions characteristic of CF airways.
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Affiliation(s)
- Dae-goon Yoo
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602
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Yoo DG, Floyd M, Winn M, Moskowitz SM, Rada B. NET formation induced by Pseudomonas aeruginosa cystic fibrosis isolates measured as release of myeloperoxidase-DNA and neutrophil elastase-DNA complexes. Immunol Lett 2014; 160:186-94. [PMID: 24670966 DOI: 10.1016/j.imlet.2014.03.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 02/28/2014] [Accepted: 03/12/2014] [Indexed: 01/19/2023]
Abstract
Cystic fibrosis (CF) airway disease is characterized by Pseudomonas aeruginosa infection and recruitment of neutrophil granulocytes. Neutrophil granule components (myeloperoxidase (MPO), human neutrophil elastase (HNE)), extracellular DNA and P. aeruginosa can all be found in the CF respiratory tract and have all been associated with worsening CF lung function. Pseudomonas-induced formation of neutrophil extracellular traps (NETs) offers a likely mechanism for release of MPO, HNE and DNA from neutrophils. NETs are composed of a DNA backbone decorated with granule proteins like MPO and HNE. Here we sought to examine whether CF clinical isolates of Pseudomonas are capable of inducing NET release from human neutrophil granulocytes. We used two methods to quantify NETs. We modified a previously employed ELISA that detects MPO-DNA complexes and established a new HNE-DNA ELISA. We show that these methods reliably quantify MPO-DNA and HNE-DNA complexes, measures of NET formation. We have found that CF isolates of P. aeruginosa stimulate robust respiratory burst and NET release in human neutrophils. By comparing paired "early" and "late" bacterial isolates obtained from the same CF patient we have found that early isolates induced significantly more NET release than late isolates. Our data support that Pseudomonas-induced NET release represents an important mechanism for release of neutrophil-derived CF inflammatory mediators, and confirm that decreased induction of NET formation is required for long-term adaptation of P. aeruginosa to CF airways.
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Affiliation(s)
- Dae-goon Yoo
- University of Georgia, College of Veterinary Medicine, Department of Infectious Diseases, 501 DW Brooks Drive, Athens, GA 30602, USA
| | - Madison Floyd
- University of Georgia, College of Veterinary Medicine, Department of Infectious Diseases, 501 DW Brooks Drive, Athens, GA 30602, USA
| | - Matthew Winn
- University of Georgia, College of Veterinary Medicine, Department of Infectious Diseases, 501 DW Brooks Drive, Athens, GA 30602, USA
| | - Samuel M Moskowitz
- Massachusetts General Hospital, Department of Pediatrics, 175 Cambridge Street, Boston, MA 02114, USA; Harvard Medical School, Department of Pediatrics, 25 Shattuck Street, Boston, MA 02115 USA
| | - Balázs Rada
- University of Georgia, College of Veterinary Medicine, Department of Infectious Diseases, 501 DW Brooks Drive, Athens, GA 30602, USA.
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Pang L, Hayes CP, Buac K, Yoo DG, Rada B. Pseudogout-Associated Inflammatory Calcium Pyrophosphate Dihydrate Microcrystals Induce Formation of Neutrophil Extracellular Traps. J I 2013; 190:6488-500. [DOI: 10.4049/jimmunol.1203215] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Rada B, Jendrysik MA, Pang L, Hayes CP, Yoo DG, Park JJ, Moskowitz SM, Malech HL, Leto TL. Pyocyanin-enhanced neutrophil extracellular trap formation requires the NADPH oxidase. PLoS One 2013; 8:e54205. [PMID: 23342104 PMCID: PMC3544820 DOI: 10.1371/journal.pone.0054205] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [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: 08/10/2012] [Accepted: 11/26/2012] [Indexed: 11/26/2022] Open
Abstract
Beyond intracellular killing, a novel neutrophil-based antimicrobial mechanism has been recently discovered: entrapment and killing by neutrophil extracellular traps (NETs). NETs consist of extruded nuclear DNA webs decorated with granule proteins. Although NET formation is an important innate immune mechanism, uncontrolled NET release damages host tissues and has been linked to several diseases including cystic fibrosis (CF). The major CF airway pathogen Pseudomonas aeruginosa establishes chronic infection. Pseudomonas imbedded within biofilms is protected against the immune system, but maintains chronic inflammation that worsens disease symptoms. Aberrant NET release from recruited neutrophils was found in CF, but the underlying mechanisms remain unclear. One of the most important Pseudomonas virulence factors is pyocyanin, a redox-active pigment that has been associated with diminished lung function in CF. Here we show that pyocyanin promotes NET formation in a time- and dose-dependent manner. Most CF Pseudomonas clinical isolates tested produce pyocyanin in vitro. Pyocyanin-derived reactive oxygen species are required for its NET release. Inhibitor experiments demonstrated involvement of Jun N-terminal Kinase (JNK) and phosphatidylinositol 3-Kinase (PI3K) in pyocyanin-induced NET formation. Pyocyanin-induced NETs also require the NADPH oxidase because NET release in chronic granulomatous disease neutrophils was greatly reduced. Comparison of neutrophils from gp91phox- and p47phox-deficient patients revealed that pyocyanin-triggered NET formation is proportional to their residual superoxide production. Our studies identify pyocyanin as the first secreted bacterial toxin that enhances NET formation. The involvement of NADPH oxidase in pyocyanin-induced NET formation represents a novel mechanism of pyocyanin toxicity.
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Affiliation(s)
- Balázs Rada
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
- * E-mail: (TLL); (BR)
| | - Meghan A. Jendrysik
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Lan Pang
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Craig P. Hayes
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Dae-goon Yoo
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Jonathan J. Park
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Samuel M. Moskowitz
- Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Harry L. Malech
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Thomas L. Leto
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
- * E-mail: (TLL); (BR)
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Rada B, Leto TL. Pyocyanin effects on respiratory epithelium: relevance in Pseudomonas aeruginosa airway infections. Trends Microbiol 2012; 21:73-81. [PMID: 23140890 DOI: 10.1016/j.tim.2012.10.004] [Citation(s) in RCA: 195] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/03/2012] [Accepted: 10/05/2012] [Indexed: 01/26/2023]
Abstract
Pseudomonas aeruginosa (PA) uses several virulence factors to establish chronic respiratory infections in bronchiectasis, chronic obstructive pulmonary disease, and cystic fibrosis (CF) patients. One of its toxins, pyocyanin (PYO), is a redox-active pigment that is required for full virulence in animal models and has been detected in patients' airway secretions. PYO promotes virulence by interfering with several cellular functions in host cells including electron transport, cellular respiration, energy metabolism, gene expression, and innate immune mechanisms. This review summarizes recent advances in PYO biology with special attention to current views on its role in human airway infections and on its interactions with the first line of our airway defense, the respiratory epithelium.
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Affiliation(s)
- Balázs Rada
- University of Georgia, College of Veterinary Medicine, Department of Infectious Diseases, 501 DW Brooks Drive, Athens, GA 30602, USA
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Rada B, Gardina P, Myers TG, Leto TL. Reactive oxygen species mediate inflammatory cytokine release and EGFR-dependent mucin secretion in airway epithelial cells exposed to Pseudomonas pyocyanin. Mucosal Immunol 2011; 4:158-71. [PMID: 20962773 PMCID: PMC3026888 DOI: 10.1038/mi.2010.62] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Despite the long-appreciated in vivo role of the redox-active virulence factor pyocyanin in Pseudomonas airway infections and the importance of airway epithelial cells in combating bacterial pathogens, little is known about pyocyanin's effect on airway epithelial cells. We find that exposure of bronchiolar epithelial cells to pyocyanin results in MUC2/MUC5AC induction and mucin secretion through release of inflammatory cytokines and growth factors (interleukin (IL)-1β, IL-6, heparin-bound epidermal growth factor, tissue growth factor-α, tumor necrosis factor-α) that activate the epidermal growth factor receptor pathway. These changes are mediated by reactive oxygen species produced by pyocyanin. Microarray analysis identified 286 pyocyanin-induced genes in airway epithelial cells, including many inflammatory mediators elevated in cystic fibrosis (granulocyte colony-stimulating factor (G-CSF), granulocyte-monocyte CSF, chemokine (C-X-C motif) ligand 1 (CXCL1), serum amyloid, IL-23) and several novel pyocyanin-responsive genes of potential importance in the infection process (IL-24, CXCL2, CXCL3, CCL20, CXCR4). This comprehensive study uncovers numerous details of pyocyanin's proinflammatory action and establishes airway epithelial cells as key responders to this microbial toxin.
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Affiliation(s)
- Balázs Rada
- National Institutes of Health, National Institute of Allergy and Infectious Diseases, Laboratory of Host Defenses, 12441 Parklawn Drive, 20852 Rockville, MD, U.S.A
| | - Paul Gardina
- National Institutes of Health, National Institute of Allergy and Infectious Diseases, Research Technologies Branch, Genomic Technologies Section, 50 South Drive, 20892 Bethesda MD, U.S.A
| | - Timothy G. Myers
- National Institutes of Health, National Institute of Allergy and Infectious Diseases, Research Technologies Branch, Genomic Technologies Section, 50 South Drive, 20892 Bethesda MD, U.S.A
| | - Thomas L. Leto
- National Institutes of Health, National Institute of Allergy and Infectious Diseases, Laboratory of Host Defenses, 12441 Parklawn Drive, 20852 Rockville, MD, U.S.A
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Yu M, Lam J, Rada B, Leto TL, Levine SJ. Double-stranded RNA induces shedding of the 34-kDa soluble TNFR1 from human airway epithelial cells via TLR3-TRIF-RIP1-dependent signaling: roles for dual oxidase 2- and caspase-dependent pathways. J Immunol 2010; 186:1180-8. [PMID: 21148036 DOI: 10.4049/jimmunol.1001499] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
TNF, an important mediator of inflammatory and innate immune responses, can be regulated by binding to soluble TNF receptors. The 55-kDa type 1 TNFR (TNFR1), the key receptor for TNF signaling, is released to the extracellular space by two mechanisms, the inducible cleavage and shedding of 34-kDa soluble TNFR1 (sTNFR1) ectodomains and the constitutive release of full-length 55-kDa TNFR1 within exosome-like vesicles. The aim of this study was to identify and characterize TLR signaling pathways that mediate TNFR1 release to the extracellular space. To our knowledge, we demonstrate for the first time that polyinosinic-polycytidylic acid [poly (I:C)], a synthetic dsRNA analogue that signals via TLR3, induces sTNFR1 shedding from human airway epithelial (NCI-H292) cells, whereas ligands for other microbial pattern recognition receptors, including TLR4, TLR7, and nucleotide-binding oligomerization domain containing 2, do not. Furthermore, poly (I:C) selectively induces the cleavage of 34-kDa sTNFR1 ectodomains but does not enhance the release of full-length 55-kDa TNFR1 within exosome-like vesicles. RNA interference experiments demonstrated that poly (I:C)-induced sTNFR1 shedding is mediated via activation of TLR3-TRIF-RIP1 signaling, with subsequent activation of two downstream pathways. One pathway involves the dual oxidase 2-mediated generation of reactive oxygen species, and the other pathway is via the caspase-mediated activation of apoptosis. Thus, the ability of dsRNA to induce the cleavage and shedding of the 34-kDa sTNFR1 from human bronchial epithelial cells represents a novel mechanism by which innate immune responses to viral infections are modulated.
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Affiliation(s)
- Man Yu
- Pulmonary and Vascular Medicine Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Rada B, Leto TL. Characterization of hydrogen peroxide production by Duox in bronchial epithelial cells exposed to Pseudomonas aeruginosa. FEBS Lett 2010; 584:917-22. [PMID: 20085766 DOI: 10.1016/j.febslet.2010.01.025] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 01/11/2010] [Accepted: 01/12/2010] [Indexed: 01/16/2023]
Abstract
Hydrogen peroxide production by the NADPH oxidase Duox1 occurs during activation of respiratory epithelial cells stimulated by purified bacterial ligands, such as lipopolysaccharide. Here, we characterize Duox activation using intact bacterial cells of several airway pathogens. We found that only Pseudomonas aeruginosa, not Burkholderia cepacia or Staphylococcus aureus, triggers H2O2 production in bronchial epithelial cells in a calcium-dependent but predominantly ATP-independent manner. Moreover, by comparing mutant Pseudomonas strains, we identify several virulence factors that participate in Duox activation, including the type-three secretion system. These data provide insight on Duox activation by mechanisms unique to P. aeruginosa.
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Affiliation(s)
- Balázs Rada
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda 20852, USA
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Rada B, Lekstrom K, Damian S, Dupuy C, Leto TL. The Pseudomonas toxin pyocyanin inhibits the dual oxidase-based antimicrobial system as it imposes oxidative stress on airway epithelial cells. J Immunol 2008; 181:4883-93. [PMID: 18802092 DOI: 10.4049/jimmunol.181.7.4883] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The dual oxidase-thiocyanate-lactoperoxidase (Duox/SCN(-)/LPO) system generates the microbicidal oxidant hypothiocyanite in the airway surface liquid by using LPO, thiocyanate, and Duox-derived hydrogen peroxide released from the apical surface of the airway epithelium. This system is effective against several microorganisms that infect airways of cystic fibrosis and other immunocompromised patients. We show herein that exposure of airway epithelial cells to Pseudomonas aeruginosa obtained from long-term cultures inhibits Duox1-dependent hydrogen peroxide release, suggesting that some microbial factor suppresses Duox activity. These inhibitory effects are not seen with the pyocyanin-deficient P. aeruginosa strain PA14 Phz1/2. We show that purified pyocyanin, a redox-active virulence factor produced by P. aeruginosa, inhibits human airway cell Duox activity by depleting intracellular stores of NADPH, as it generates intracellular superoxide. Long-term exposure of human airway (primary normal human bronchial and NCI-H292) cells to pyocyanin also blocks induction of Duox1 by Th2 cytokines (IL-4, IL-13), which was prevented by the antioxidants glutathione and N-acetylcysteine. Furthermore, we showed that low concentrations of pyocyanin blocked killing of wild-type P. aeruginosa by the Duox/SCN(-)/LPO system on primary normal human bronchial epithelial cells. Thus, pyocyanin can subvert Pseudomonas killing by the Duox-based system as it imposes oxidative stress on the host. We also show that lactoperoxidase can oxidize pyocyanin, thereby diminishing its cytotoxicity. These data establish a novel role for pyocyanin in the survival of P. aeruginosa in human airways through competitive redox-based reactions between the pathogen and host.
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Affiliation(s)
- Balázs Rada
- National Institutes of Health, National Institute of Allergy and Infectious Diseases, Laboratory of Host Defenses, Rockville, MD 20852, USA
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