1
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Meganathan V, Hamilton CE, Natarajan K, Keshava S, Boggaram V. NADPH and xanthine oxidases control induction of inflammatory mediator expression by organic dust in the lung. FASEB J 2022; 36:e22381. [PMID: 35661421 DOI: 10.1096/fj.202100732r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 04/29/2022] [Accepted: 05/16/2022] [Indexed: 11/11/2022]
Abstract
Exposure to organic dust in animal and agricultural farms and the ensuing lung inflammation are linked to the development of respiratory diseases. We found previously that elevated production of reactive oxygen species (ROS) by aqueous poultry organic dust extract (hereafter referred to as dust extract) mediates induction of proinflammatory mediators in airway epithelial cells. In the present study, we investigated whether ROS generated by NADPH oxidases (NOX) and xanthine oxidase (XO) controls induction of inflammatory mediators by dust extract and the underlying mechanisms in bronchial epithelial cells. Using chemical inhibitors and siRNA targeted knockdown, we found that NOX1, NOX2, NOX4, and XO-derived ROS regulates induction of proinflammatory mediator levels. Like airway epithelial cells in vitro, NOX inhibitor VAS2870 reduced keratinocyte chemoattractant (KC), IL-6, and TNF-α production and 4-hydroxynonenal (4-HNE) staining induced by dust extract in mouse lungs. VAS2870 inhibition of proinflammatory mediators was associated with reduced NFκB and Stat3 activation indicating that NOX generated ROS activates NFκB and Stat3 to induce proinflammatory gene expression. Dust extract increased the membrane association of p47phox in airway epithelial cells indicating NOX2 activation but had no effect on NOX2 protein levels. In summary, our studies have shown that NOX and XO generated ROS control organic dust induction of proinflammatory mediators in airway epithelial cells via NFκB and Stat3 activation.
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Affiliation(s)
- Velmurugan Meganathan
- Department of Cellular and Molecular Biology, Health Science Center, University of Texas at Tyler, Tyler, Texas, USA
| | - Cory E Hamilton
- Department of Cellular and Molecular Biology, Health Science Center, University of Texas at Tyler, Tyler, Texas, USA
| | - Kartiga Natarajan
- Department of Cellular and Molecular Biology, Health Science Center, University of Texas at Tyler, Tyler, Texas, USA
| | - Shiva Keshava
- Department of Cellular and Molecular Biology, Health Science Center, University of Texas at Tyler, Tyler, Texas, USA
| | - Vijay Boggaram
- Department of Cellular and Molecular Biology, Health Science Center, University of Texas at Tyler, Tyler, Texas, USA
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2
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Shrestha D, Massey N, Bhat SM, Jelesijević T, Sahin O, Zhang Q, Bailey KL, Poole JA, Charavaryamath C. Nrf2 Activation Protects Against Organic Dust and Hydrogen Sulfide Exposure Induced Epithelial Barrier Loss and K. pneumoniae Invasion. Front Cell Infect Microbiol 2022; 12:848773. [PMID: 35521223 PMCID: PMC9062039 DOI: 10.3389/fcimb.2022.848773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 03/21/2022] [Indexed: 11/23/2022] Open
Abstract
Agriculture workers report various respiratory symptoms owing to occupational exposure to organic dust (OD) and various gases. Previously, we demonstrated that pre-exposure to hydrogen sulfide (H2S) alters the host response to OD and induces oxidative stress. Nrf2 is a master-regulator of host antioxidant response and exposures to toxicants is known to reduce Nrf2 activity. The OD exposure-induced lung inflammation is known to increase susceptibility to a secondary microbial infection. We tested the hypothesis that repeated exposure to OD or H2S leads to loss of Nrf2, loss of epithelial cell integrity and that activation of Nrf2 rescues this epithelial barrier dysfunction. Primary normal human bronchial epithelial (NHBE) cells or mouse precision cut-lung slices (PCLS) were treated with media, swine confinement facility organic dust extract (ODE) or H2S or ODE+H2S for one or five days. Cells were also pretreated with vehicle control (DMSO) or RTA-408, a Nrf2 activator. Acute exposure to H2S and ODE+H2S altered the cell morphology, decreased the viability as per the MTT assay, and reduced the Nrf2 expression as well as increased the keap1 levels in NHBE cells. Repeated exposure to ODE or H2S or ODE+H2S induced oxidative stress and cytokine production, decreased tight junction protein occludin and cytoskeletal protein ezrin expression, disrupted epithelial integrity and resulted in increased Klebsiella pneumoniae invasion. RTA-408 (pharmacological activator of Nrf2) activated Nrf2 by decreasing keap1 levels and reduced ODE+H2S-induced changes including reversing loss of barrier integrity, inflammatory cytokine production and microbial invasion in PCLS but not in NHBE cell model. We conclude that Nrf2 activation has a partial protective function against ODE and H2S.
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Affiliation(s)
- Denusha Shrestha
- Department of Biomedical Sciences, Iowa State University, Ames, IA, United States
| | - Nyzil Massey
- Department of Biomedical Sciences, Iowa State University, Ames, IA, United States
| | - Sanjana Mahadev Bhat
- Department of Biomedical Sciences, Iowa State University, Ames, IA, United States
- Immunobiology Interdepartmental Graduate Program, Iowa State University, Ames, IA, United States
| | - Tomislav Jelesijević
- Department of Comparative Biomedical Sciences, Louisiana State University, Baton Rouge, LA, United States
| | - Orhan Sahin
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, United States
| | - Qijing Zhang
- Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, United States
| | - Kristina L. Bailey
- Department of Internal Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, University of Nebraska Medical Center, Omaha, NE, United States
| | - Jill A. Poole
- Department of Medicine, University of Nebraska Medical Center, Omaha, NE, United States
| | - Chandrashekhar Charavaryamath
- Department of Biomedical Sciences, Iowa State University, Ames, IA, United States
- *Correspondence: Chandrashekhar Charavaryamath,
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3
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Chu SJ, Tang SE, Pao HP, Wu SY, Liao WI. Protease-Activated Receptor-1 Antagonist Protects Against Lung Ischemia/Reperfusion Injury. Front Pharmacol 2021; 12:752507. [PMID: 34658893 PMCID: PMC8514687 DOI: 10.3389/fphar.2021.752507] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/20/2021] [Indexed: 01/14/2023] Open
Abstract
Protease-activated receptor (PAR)-1 is a thrombin-activated receptor that plays an essential role in ischemia/reperfusion (IR)-induced acute inflammation. PAR-1 antagonists have been shown to alleviate injuries in various IR models. However, the effect of PAR-1 antagonists on IR-induced acute lung injury (ALI) has not yet been elucidated. This study aimed to investigate whether PAR-1 inhibition could attenuate lung IR injury. Lung IR was induced in an isolated perfused rat lung model. Male rats were treated with the specific PAR-1 antagonist SCH530348 (vorapaxar) or vehicle, followed by ischemia for 40 min and reperfusion for 60 min. To examine the role of PAR-1 and the mechanism of SCH530348 in lung IR injury, western blotting and immunohistochemical analysis of lung tissue were performed. In vitro, mouse lung epithelial cells (MLE-12) were treated with SCH530348 or vehicle and subjected to hypoxia-reoxygenation (HR). We found that SCH530348 decreased lung edema and neutrophil infiltration, attenuated thrombin production, reduced inflammatory factors, including cytokine-induced neutrophil chemoattractant-1, interleukin-6 and tumor necrosis factor-α, mitigated lung cell apoptosis, and downregulated the phosphoinositide 3-kinase (PI3K), nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways in IR-injured lungs. In addition, SCH530348 prevented HR-induced NF-κB activation and inflammatory chemokine production in MLE12 cells. Our results demonstrate that SCH530348 exerts protective effects by blocking PAR-1 expression and modulating the downstream PI3K, NF-κB and MAPK pathways. These findings indicate that the PAR-1 antagonist protects against IR-induced ALI and is a potential therapeutic candidate for lung protection following IR injury.
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Affiliation(s)
- Shi-Jye Chu
- Department of Internal Medicine, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan
| | - Shih-En Tang
- Division of Pulmonary and Critical Care, Department of Internal Medicine, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan.,Institute of Aerospace and Undersea Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Hsin-Ping Pao
- The Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Shu-Yu Wu
- Institute of Aerospace and Undersea Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Wen-I Liao
- Department of Emergency Medicine, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan
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4
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Vostrikova SM, Grinev AB, Gogvadze VG. Reactive Oxygen Species and Antioxidants in Carcinogenesis and Tumor Therapy. BIOCHEMISTRY (MOSCOW) 2021; 85:1254-1266. [PMID: 33202210 DOI: 10.1134/s0006297920100132] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Strictly regulated balance between the formation and utilization of reactive oxygen species (ROS) is the basis of normal functioning of organisms. ROS play an important role in the regulation of many metabolic processes; however, excessive content of ROS leads to the development of various disorders, including oncological diseases, as a result of ROS-induced mutations in DNA. In tumors, high levels of oxygen radicals promote cell proliferation and metastasis. On the other hand, high content of ROS can trigger cell death, a phenomenon used in the antitumor therapy. Water- and lipid-soluble antioxidants, as well as antioxidant enzyme systems, can inhibit ROS generation; however, they should be used with caution. Antioxidants can suppress ROS-dependent cell proliferation and metastasis, but at the same time, they may inhibit the death of tumor cells if the antitumor therapeutic agents stimulate oxidative stress. The data on the role of antioxidants in the death of tumor cells and on the effects of antioxidants taken as dietary supplements during antitumor therapy, are contradictory. This review focuses on the mechanisms by which antioxidants can affect tumor and healthy cells.
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Affiliation(s)
- S M Vostrikova
- Faculty of Medicine, Lomonosov Moscow State University, Moscow, 119192, Russia.,I. M. Sechenov First Moscow State Medical University of the Ministry of Health of the Russian Federation (Sechenov University), Moscow, 119991, Russia
| | - A B Grinev
- I. M. Sechenov First Moscow State Medical University of the Ministry of Health of the Russian Federation (Sechenov University), Moscow, 119991, Russia
| | - V G Gogvadze
- Faculty of Medicine, Lomonosov Moscow State University, Moscow, 119192, Russia. .,Division of Toxicology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, 171 77, Sweden
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5
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Rovai ES, Alves T, Holzhausen M. Protease-activated receptor 1 as a potential therapeutic target for COVID-19. Exp Biol Med (Maywood) 2021; 246:688-694. [PMID: 33302737 PMCID: PMC7746952 DOI: 10.1177/1535370220978372] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Acute respiratory disease caused by a novel coronavirus (SARS-CoV-2) has spread all over the world, since its discovery in 2019, Wuhan, China. This disease is called COVID-19 and already killed over 1 million people worldwide. The clinical symptoms include fever, dry cough, dyspnea, headache, dizziness, generalized weakness, vomiting, and diarrhea. Unfortunately, so far, there is no validated vaccine, and its management consists mainly of supportive care. Venous thrombosis and pulmonary embolism are highly prevalent in patients suffering from severe COVID-19. In fact, a prothrombotic state seems to be present in most fatal cases of the disease. SARS-CoV-2 leads to the production of proinflammatory cytokines, causing immune-mediated tissue damage, disruption of the endothelial barrier, and uncontrolled thrombogenesis. Thrombin is the key regulator of coagulation and fibrin formation. In severe COVID-19, a dysfunctional of physiological anticoagulant mechanisms leads to a progressive increase of thrombin activity, which is associated with acute respiratory distress syndrome development and a poor prognosis. Protease-activated receptor type 1 (PAR1) is the main thrombin receptor and may represent an essential link between coagulation and inflammation in the pathophysiology of COVID-19. In this review, we discuss the potential role of PAR1 inhibition and regulation in COVID-19 treatment.
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Affiliation(s)
- Emanuel S. Rovai
- Department of Dentistry, University of Taubate, Taubate 12010-490, Brazil
| | - Tomaz Alves
- Division of Periodontics, Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo 05508-000, Brazil
| | - Marinella Holzhausen
- Division of Periodontics, Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo 05508-000, Brazil
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6
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McNulty MJ, Silberstein DZ, Kuhn BT, Padgett HS, Nandi S, McDonald KA, Cross CE. Alpha-1 antitrypsin deficiency and recombinant protein sources with focus on plant sources: Updates, challenges and perspectives. Free Radic Biol Med 2021; 163:10-30. [PMID: 33279618 DOI: 10.1016/j.freeradbiomed.2020.11.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/20/2020] [Accepted: 11/24/2020] [Indexed: 12/16/2022]
Abstract
Alpha-1 antitrypsin deficiency (A1ATD) is an autosomal recessive disease characterized by low plasma levels of A1AT, a serine protease inhibitor representing the most abundant circulating antiprotease normally present at plasma levels of 1-2 g/L. The dominant clinical manifestations include predispositions to early onset emphysema due to protease/antiprotease imbalance in distal lung parenchyma and liver disease largely due to unsecreted polymerized accumulations of misfolded mutant A1AT within the endoplasmic reticulum of hepatocytes. Since 1987, the only FDA licensed specific therapy for the emphysema component has been infusions of A1AT purified from pooled human plasma at the 2020 cost of up to US $200,000/year with the risk of intermittent shortages. In the past three decades various, potentially less expensive, recombinant forms of human A1AT have reached early stages of development, one of which is just reaching the stage of human clinical trials. The focus of this review is to update strategies for the treatment of the pulmonary component of A1ATD with some focus on perspectives for therapeutic production and regulatory approval of a recombinant product from plants. We review other competitive technologies for treating the lung disease manifestations of A1ATD, highlight strategies for the generation of data potentially helpful for securing FDA Investigational New Drug (IND) approval and present challenges in the selection of clinical trial strategies required for FDA licensing of a New Drug Approval (NDA) for this disease.
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Affiliation(s)
- Matthew J McNulty
- Department of Chemical Engineering, University of California, Davis, CA, USA
| | - David Z Silberstein
- Department of Chemical Engineering, University of California, Davis, CA, USA
| | - Brooks T Kuhn
- Department of Internal Medicine, University of California, Davis, CA, USA; University of California, Davis, Alpha-1 Deficiency Clinic, Sacramento, CA, USA
| | | | - Somen Nandi
- Department of Chemical Engineering, University of California, Davis, CA, USA; Global HealthShare Initiative®, University of California, Davis, CA, USA
| | - Karen A McDonald
- Department of Chemical Engineering, University of California, Davis, CA, USA; Global HealthShare Initiative®, University of California, Davis, CA, USA
| | - Carroll E Cross
- Department of Internal Medicine, University of California, Davis, CA, USA; University of California, Davis, Alpha-1 Deficiency Clinic, Sacramento, CA, USA; Department of Physiology and Membrane Biology, University of California, Davis, CA, USA.
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7
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Davis KU, Sheats MK. The Role of Neutrophils in the Pathophysiology of Asthma in Humans and Horses. Inflammation 2020; 44:450-465. [PMID: 33150539 DOI: 10.1007/s10753-020-01362-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/07/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022]
Abstract
Asthma is a common and debilitating chronic airway disease that affects people and horses of all ages worldwide. While asthma in humans most commonly involves an excessive type 2 immune response and eosinophilic inflammation, neutrophils have also been recognized as key players in the pathophysiology of asthma, including in the severe asthma phenotype where neutrophilic inflammation predominates. Severe equine asthma syndrome (sEAS) features prominent neutrophilic inflammation and has been increasingly used as a naturally occurring animal model for the study of human neutrophilic asthma. This comparative review examines the recent literature in order to explore the role of neutrophil inflammatory functions in the pathophysiology and immunology of asthma in humans and horses.
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Affiliation(s)
- Kaori Uchiumi Davis
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 1060 William Moore Dr., Raleigh, NC, 27607, USA.,Center for Comparative Medicine and Translational Research, North Carolina State University, 1060 William Moore Dr, Raleigh, NC, 27607, USA
| | - M Katie Sheats
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 1060 William Moore Dr., Raleigh, NC, 27607, USA. .,Center for Comparative Medicine and Translational Research, North Carolina State University, 1060 William Moore Dr, Raleigh, NC, 27607, USA.
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8
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Meganathan V, Moyana R, Natarajan K, Kujur W, Kusampudi S, Mulik S, Boggaram V. Bacterial extracellular vesicles isolated from organic dust induce neutrophilic inflammation in the lung. Am J Physiol Lung Cell Mol Physiol 2020; 319:L893-L907. [PMID: 32996778 DOI: 10.1152/ajplung.00107.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Inhalation of organic dust is an occupational hazard leading to the development of respiratory symptoms and respiratory diseases. Bioaerosols from concentrated animal feeding operations are rich in bacteria and could carry bacterial extracellular vesicles (EVs) that could induce lung inflammation. It is not known if organic dust contains bacterial EVs and whether they modulate lung inflammation. Herein, we show that poultry organic dust contains bacterial EVs (dust EVs) that induce lung inflammation. Treatment of airway epithelial cells, THP-1-monocytes and -macrophages with dust EVs rapidly induced IL-8, IL-6, ICAM-1, proIL-1β, and TNF-α levels. In airway epithelial cells, induction of inflammatory mediators was due to increased mRNA levels and NF-κB activation. Induction of inflammatory mediators by dust EVs was not inhibited by polymyxin B. Single and repeated treatments of mice with dust EVs increased lung KC, IL-6, and TNF-α levels without significantly altering IL-17A levels. Increases in cytokines were associated with enhanced neutrophil infiltration into the lung. Repeated treatments of mice with dust EVs increased lung mean linear intercept and increased collagen deposition around airways indicating lung remodeling. Peribronchial cell infiltrates and airway epithelial thickening were also observed in treated mice. Because bacterial EVs are nanometer-sized particles, they can reach and accumulate in the bronchiolar and alveolar regions causing lung injury leading to the development of respiratory diseases. Our studies have provided new evidence for the presence of bacterial EVs in organic dust and for their role as one of the causative agents of organic dust-induced lung inflammation and lung injury.
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Affiliation(s)
- Velmurugan Meganathan
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas
| | - Regina Moyana
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas
| | - Kartiga Natarajan
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas
| | - Weshely Kujur
- Department of Pulmonary Immunology, University of Texas Health Science Center at Tyler, Tyler, Texas
| | - Shilpa Kusampudi
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas
| | - Sachin Mulik
- Department of Pulmonary Immunology, University of Texas Health Science Center at Tyler, Tyler, Texas
| | - Vijay Boggaram
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas
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9
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Huff RD, Carlsten C, Hirota JA. An update on immunologic mechanisms in the respiratory mucosa in response to air pollutants. J Allergy Clin Immunol 2020; 143:1989-2001. [PMID: 31176381 DOI: 10.1016/j.jaci.2019.04.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/16/2019] [Accepted: 04/23/2019] [Indexed: 12/11/2022]
Abstract
Every day, we breathe in more than 10,000 L of air that contains a variety of air pollutants that can pose negative consequences to lung health. The respiratory mucosa formed by the airway epithelium is the first point of contact for air pollution in the lung, functioning as a mechanical and immunologic barrier. Under normal circumstances, airway epithelial cells connected by tight junctions secrete mucus, airway surface lining fluid, host defense peptides, and antioxidants and express innate immune pattern recognition receptors to respond to inhaled foreign substances and pathogens. Under conditions of air pollution exposure, the defenses of the airway epithelium are compromised by reductions in barrier function, impaired host defense to pathogens, and exaggerated inflammatory responses. Central to the mechanical and immunologic changes induced by air pollution are activation of redox-sensitive pathways and a role for antioxidants in normalizing these negative effects. Genetic variants in genes important in epithelial cell function and phenotype contribute to a diversity of responses to air pollution in the population at the individual and group levels and suggest a need for personalized approaches to attenuate the respiratory mucosal immune responses to air pollution.
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Affiliation(s)
- Ryan D Huff
- Division of Respiratory Medicine, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chris Carlsten
- Division of Respiratory Medicine, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jeremy A Hirota
- Division of Respiratory Medicine, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Firestone Institute for Respiratory Health, Division of Respirology, Department of Medicine, Hamilton, Ontario, Canada; McMaster Immunology Research Centre, McMaster University, Hamilton, Ontario, Canada; Department of Medicine, McMaster University, Hamilton, Ontario, Canada; Department of Biology, University of Waterloo, Waterloo, Ontario, Canada.
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10
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Natarajan K, Gangam K, Meganathan V, Gottipati KR, Mitchell C, Boggaram V. Organic dust inhibits surfactant protein expression by reducing thyroid transcription factor-1 levels in human lung epithelial cells. Innate Immun 2020; 25:118-131. [PMID: 30774012 PMCID: PMC6830861 DOI: 10.1177/1753425919827360] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Exposure to organic dust is a risk factor for the development of respiratory
diseases. Surfactant proteins (SP) reduce alveolar surface tension and modulate
innate immune responses to control lung inflammation. Therefore, changes in SP
levels could contribute to the development of organic-dust-induced respiratory
diseases. Because information on the effects of organic dust on SP levels is
lacking, we studied the effects of dust from a poultry farm on SP expression. We
found that dust extract reduced SP-A and SP-B mRNA and protein levels in H441
human lung epithelial cells by inhibiting their promoter activities, but did not
have any effect on SP-D protein levels. Dust extract also reduced SP-A and SP-C
levels in primary human alveolar epithelial cells. The inhibitory effects were
not due to LPS or protease activities present in dust extract or mediated via
oxidative stress, but were dependent on a heat-labile factor(s). Thyroid
transcription factor-1, a key transcriptional activator of SP expression, was
reduced in dust-extract-treated cells, indicating that its down-regulation
mediates inhibition of SP levels. Our study implies that down-regulation of SP
levels by organic dust could contribute to the development of lung inflammation
and respiratory diseases in humans.
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Affiliation(s)
- Kartiga Natarajan
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, USA
| | - Keerthi Gangam
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, USA
| | - Velmurugan Meganathan
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, USA
| | - Koteswara R Gottipati
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, USA
| | - Courtney Mitchell
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, USA
| | - Vijay Boggaram
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, USA
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11
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Natarajan K, Meganathan V, Mitchell C, Boggaram V. Organic dust induces inflammatory gene expression in lung epithelial cells via ROS-dependent STAT-3 activation. Am J Physiol Lung Cell Mol Physiol 2019; 317:L127-L140. [PMID: 31042082 DOI: 10.1152/ajplung.00448.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exposure to dust in agricultural and animal environments, known as organic dust, is associated with the development of respiratory symptoms and respiratory diseases. Inflammation is a key feature of lung pathologies associated with organic dust exposure, and exposure to organic dust induces the expression of several immune and inflammatory mediators. However, information on transcription factors and cellular and molecular mechanisms controlling the production of immune and inflammatory mediators induced by organic dust is limited. In this study, we have identified STAT-3 as an important transcription factor controlling the induction of expression of immune and inflammatory mediators by poultry dust extracts in airway epithelial cells and in mouse lungs and delineated the cellular pathway for STAT-3 activation. Poultry dust extract activated STAT-3 phosphorylation in Beas2B and normal human bronchial epithelial cells and in mouse lungs. Chemical inhibition and siRNA knockdown of STAT-3 suppressed induction of immune and inflammatory mediator expression. Antioxidants suppressed the increase of STAT-3 phosphorylation induced by poultry dust extract indicating that oxidative stress [elevated reactive oxygen species (ROS) levels] is important for the activation. Chemical inhibition and siRNA knockdown experiments demonstrated that STAT-3 activation is dependent on the activation of nonreceptor tyrosine-protein kinase 2 (TYK2) and epidermal growth factor receptor (EGFR) tyrosine kinases. Our studies show that poultry dust extract controls the induction of immune and inflammatory mediator expression via a cellular pathway involving oxidative stress-mediated STAT-3 activation by TYK2 and EGFR tyrosine kinases.
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Affiliation(s)
- Kartiga Natarajan
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler , Tyler, Texas
| | - Velmurugan Meganathan
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler , Tyler, Texas
| | - Courtney Mitchell
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler , Tyler, Texas
| | - Vijay Boggaram
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler , Tyler, Texas
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