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Shrestha Palikhe N, Haji Q, Mack E, Sinnatamby T, Sandford AJ, Cameron L, Vliagoftis H. Association of single nucleotide polymorphisms in the F2RL1 gene with clinical and inflammatory characteristics of patients with asthma. ALLERGY, ASTHMA, AND CLINICAL IMMUNOLOGY : OFFICIAL JOURNAL OF THE CANADIAN SOCIETY OF ALLERGY AND CLINICAL IMMUNOLOGY 2024; 20:8. [PMID: 38308375 PMCID: PMC10837890 DOI: 10.1186/s13223-024-00873-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 01/07/2024] [Indexed: 02/04/2024]
Abstract
BACKGROUND Proteinase-activated receptor 2 (PAR-2) is a G-protein coupled receptor associated with many inflammatory diseases, including asthma. We have shown an association between PAR-2 expression in peripheral blood monocytes and asthma severity as well as blood PAR-2 mRNA level and lung function. Since F2RL1 (the gene encoding PAR-2) polymorphisms affect PAR-2 expression, we hypothesize they may affect asthma severity. METHODS We recruited 76 subjects with asthma of varying severity and collected clinical (FEV1 [% predicted], FEV1/FVC, IgE) and immunological (PAR-2 mRNA, blood eosinophils) disease parameters. We also genotyped these individuals for 3 F2RL1 SNPs (-45C/T, -149C/G, c.621C/T). RESULTS We found that the F2RL1 SNP "C" allele of -45C/T (rs1529505) was associated with PAR-2 mRNA and blood eosinophils. F2RL1 SNP c.621C/T (rs631465) was associated with PAR-2 mRNA. The F2RL1 SNP -149C/G (rs2242991) had no association with any of the parameters studied. This study identified one F2RL1 SNP rs1529505 is associated with parameters of asthma, but not asthma severity. CONCLUSION Larger studies are needed to further elucidate the role of PAR-2 in the pathophysiology of asthma and the influence of genetic variation.
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Affiliation(s)
- Nami Shrestha Palikhe
- Division of Pulmonary Medicine, Department of Medicine, Faculty of Medicine & Dentistry, University of Alberta, 550 A HMRC, Edmonton, AB, T6G 2S2, Canada.
- Alberta Respiratory Centre, University of Alberta, Edmonton, AB, Canada.
| | - Qahir Haji
- Division of Pulmonary Medicine, Department of Medicine, Faculty of Medicine & Dentistry, University of Alberta, 550 A HMRC, Edmonton, AB, T6G 2S2, Canada
| | - Emily Mack
- Division of Pulmonary Medicine, Department of Medicine, Faculty of Medicine & Dentistry, University of Alberta, 550 A HMRC, Edmonton, AB, T6G 2S2, Canada
- Faculty of Education, University of Alberta, Edmonton, Canada
| | - Tristan Sinnatamby
- Division of Pulmonary Medicine, Department of Medicine, Faculty of Medicine & Dentistry, University of Alberta, 550 A HMRC, Edmonton, AB, T6G 2S2, Canada
| | - Andrew J Sandford
- Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, BC, Canada
| | - Lisa Cameron
- Division of Pulmonary Medicine, Department of Medicine, Faculty of Medicine & Dentistry, University of Alberta, 550 A HMRC, Edmonton, AB, T6G 2S2, Canada
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Harissios Vliagoftis
- Division of Pulmonary Medicine, Department of Medicine, Faculty of Medicine & Dentistry, University of Alberta, 550 A HMRC, Edmonton, AB, T6G 2S2, Canada.
- Alberta Respiratory Centre, University of Alberta, Edmonton, AB, Canada.
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Chu TY, Zheng-Gérard C, Huang KY, Chang YC, Chen YW, I KY, Lo YL, Chiang NY, Chen HY, Stacey M, Gordon S, Tseng WY, Sun CY, Wu YM, Pan YS, Huang CH, Lin CY, Chen TC, El Omari K, Antonelou M, Henderson SR, Salama A, Seiradake E, Lin HH. GPR97 triggers inflammatory processes in human neutrophils via a macromolecular complex upstream of PAR2 activation. Nat Commun 2022; 13:6385. [PMID: 36302784 PMCID: PMC9613636 DOI: 10.1038/s41467-022-34083-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 10/13/2022] [Indexed: 12/25/2022] Open
Abstract
Neutrophils play essential anti-microbial and inflammatory roles in host defense, however, their activities require tight regulation as dysfunction often leads to detrimental inflammatory and autoimmune diseases. Here we show that the adhesion molecule GPR97 allosterically activates CD177-associated membrane proteinase 3 (mPR3), and in conjugation with several protein interaction partners leads to neutrophil activation in humans. Crystallographic and deletion analysis of the GPR97 extracellular region identified two independent mPR3-binding domains. Mechanistically, the efficient binding and activation of mPR3 by GPR97 requires the macromolecular CD177/GPR97/PAR2/CD16b complex and induces the activation of PAR2, a G protein-coupled receptor known for its function in inflammation. Triggering PAR2 by the upstream complex leads to strong inflammatory activation, prompting anti-microbial activities and endothelial dysfunction. The role of the complex in pathologic inflammation is underscored by the finding that both GPR97 and mPR3 are upregulated on the surface of disease-associated neutrophils. In summary, we identify a PAR2 activation mechanism that directs neutrophil activation, and thus inflammation. The PR3/CD177/GPR97/PAR2/CD16b protein complex, therefore, represents a potential therapeutic target for neutrophil-mediated inflammatory diseases.
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Affiliation(s)
- Tai-Ying Chu
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | | | - Kuan-Yeh Huang
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yu-Chi Chang
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ying-Wen Chen
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Kuan-Yu I
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yu-Ling Lo
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Nien-Yi Chiang
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Hsin-Yi Chen
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Martin Stacey
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Siamon Gordon
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Wen-Yi Tseng
- Division of Rheumatology, Allergy and Immunology, Chang Gung Memorial Hospital-Keelung, Keelung, Taiwan
| | - Chiao-Yin Sun
- Department of Nephrology, Chang Gung Memorial Hospital-Keelung, Keelung, Taiwan
- Department of Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yen-Mu Wu
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital-Linkou, Taoyuan, Taiwan
| | - Yi-Shin Pan
- Department of Gastroenterology and Hepatology, Chang Gung Memorial Hospital-Linkou, Taoyuan, Taiwan
| | - Chien-Hao Huang
- Department of Gastroenterology and Hepatology, Chang Gung Memorial Hospital-Linkou, Taoyuan, Taiwan
| | - Chun-Yen Lin
- Department of Gastroenterology and Hepatology, Chang Gung Memorial Hospital-Linkou, Taoyuan, Taiwan
| | - Tse-Ching Chen
- Department of Anatomic Pathology, Chang Gung Memorial Hospital-Linkou, Taoyuan, Taiwan
| | - Kamel El Omari
- Diamond Light Source Limited, Harwell Science and Innovation Campus, Didcot, UK
| | | | | | - Alan Salama
- Department of Renal Medicine, Royal Free Campus, UCL, London, UK
| | - Elena Seiradake
- Department of Biochemistry, University of Oxford, Oxford, UK.
| | - Hsi-Hsien Lin
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
- Division of Rheumatology, Allergy and Immunology, Chang Gung Memorial Hospital-Keelung, Keelung, Taiwan.
- Department of Anatomic Pathology, Chang Gung Memorial Hospital-Linkou, Taoyuan, Taiwan.
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Consalvo KM, Kirolos SA, Sestak CE, Gomer RH. Sex-Based Differences in Human Neutrophil Chemorepulsion. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 209:354-367. [PMID: 35793910 PMCID: PMC9283293 DOI: 10.4049/jimmunol.2101103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 04/02/2022] [Indexed: 05/25/2023]
Abstract
A considerable amount is known about how eukaryotic cells move toward an attractant, and the mechanisms are conserved from Dictyostelium discoideum to human neutrophils. Relatively little is known about chemorepulsion, where cells move away from a repellent signal. We previously identified pathways mediating chemorepulsion in Dictyostelium, and here we show that these pathways, including Ras, Rac, protein kinase C, PTEN, and ERK1 and 2, are required for human neutrophil chemorepulsion, and, as with Dictyostelium chemorepulsion, PI3K and phospholipase C are not necessary, suggesting that eukaryotic chemorepulsion mechanisms are conserved. Surprisingly, there were differences between male and female neutrophils. Inhibition of Rho-associated kinases or Cdc42 caused male neutrophils to be more repelled by a chemorepellent and female neutrophils to be attracted to the chemorepellent. In the presence of a chemorepellent, compared with male neutrophils, female neutrophils showed a reduced percentage of repelled neutrophils, greater persistence of movement, more adhesion, less accumulation of PI(3,4,5)P3, and less polymerization of actin. Five proteins associated with chemorepulsion pathways are differentially abundant, with three of the five showing sex dimorphism in protein localization in unstimulated male and female neutrophils. Together, this indicates a fundamental difference in a motility mechanism in the innate immune system in men and women.
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Affiliation(s)
| | - Sara A Kirolos
- Department of Biology, Texas A&M University, College Station, TX
| | - Chelsea E Sestak
- Department of Biology, Texas A&M University, College Station, TX
| | - Richard H Gomer
- Department of Biology, Texas A&M University, College Station, TX
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Protease-activated receptor 2 enhances innate and inflammatory mechanisms induced by lipopolysaccharide in macrophages from C57BL/6 mice. Inflamm Res 2022; 71:439-448. [PMID: 35274151 DOI: 10.1007/s00011-022-01551-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 02/11/2022] [Accepted: 02/16/2022] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE This study was conducted to investigate the effects of the synthetic PAR2 agonist peptide (PAR2-AP) SLIGRL-NH2 on LPS-induced inflammatory mechanisms in peritoneal macrophages. METHODS Peritoneal macrophages obtained from C57BL/6 mice were incubated with PAR2-AP and/or LPS, and the phagocytosis of zymosan fluorescein isothiocyanate (FITC) particles; nitric oxide (NO), reactive oxygen species (ROS), and cytokine production; and inducible NO synthase (iNOS) expression in macrophages co-cultured with PAR-2-AP/LPS were evaluated. RESULTS Co-incubation of macrophages with PAR2AP (30 µM)/LPS (100 ng/mL) enhanced LPS-induced phagocytosis; production of NO, ROS, and the pro-inflammatory cytokines interleukin (IL)-1β, tumour necrosis factor (TNF)-α, IL-6, and C-C motif chemokine ligand (CCL)2; and iNOS expression and impaired the release of the anti-inflammatory cytokine IL-10 after 4 h of co-stimulation. In addition, PAR2AP increased the LPS-induced translocation of the p65 subunit of the pro-inflammatory transcription factor nuclear factor kappa B (NF-κB) and reduced the expression of inhibitor of NF-κB. CONCLUSION This study provides evidence of a role for PAR2 in macrophage response triggered by LPS enhancing the phagocytic activity and NO, ROS, and cytokine production, resulting in the initial and adequate macrophage response required for their innate response mechanisms.
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Signaling Pathways Potentially Responsible for Foam Cell Formation: Cholesterol Accumulation or Inflammatory Response-What is First? Int J Mol Sci 2020; 21:ijms21082716. [PMID: 32295185 PMCID: PMC7216009 DOI: 10.3390/ijms21082716] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/03/2020] [Accepted: 04/07/2020] [Indexed: 02/07/2023] Open
Abstract
Accumulation of lipid-laden (foam) cells in the arterial wall is known to be the earliest step in the pathogenesis of atherosclerosis. There is almost no doubt that atherogenic modified low-density lipoproteins (LDL) are the main sources of accumulating lipids in foam cells. Atherogenic modified LDL are taken up by arterial cells, such as macrophages, pericytes, and smooth muscle cells in an unregulated manner bypassing the LDL receptor. The present study was conducted to reveal possible common mechanisms in the interaction of macrophages with associates of modified LDL and non-lipid latex particles of a similar size. To determine regulatory pathways that are potentially responsible for cholesterol accumulation in human macrophages after the exposure to naturally occurring atherogenic or artificially modified LDL, we used transcriptome analysis. Previous studies of our group demonstrated that any type of LDL modification facilitates the self-association of lipoprotein particles. The size of such self-associates hinders their interaction with a specific LDL receptor. As a result, self-associates are taken up by nonspecific phagocytosis bypassing the LDL receptor. That is why we used latex beads as a stimulator of macrophage phagocytotic activity. We revealed at least 12 signaling pathways that were regulated by the interaction of macrophages with the multiple-modified atherogenic naturally occurring LDL and with latex beads in a similar manner. Therefore, modified LDL was shown to stimulate phagocytosis through the upregulation of certain genes. We have identified at least three genes (F2RL1, EIF2AK3, and IL15) encoding inflammatory molecules and associated with signaling pathways that were upregulated in response to the interaction of modified LDL with macrophages. Knockdown of two of these genes, EIF2AK3 and IL15, completely suppressed cholesterol accumulation in macrophages. Correspondingly, the upregulation of EIF2AK3 and IL15 promoted cholesterol accumulation. These data confirmed our hypothesis of the following chain of events in atherosclerosis: LDL particles undergo atherogenic modification; this is accompanied by the formation of self-associates; large LDL associates stimulate phagocytosis; as a result of phagocytosis stimulation, pro-inflammatory molecules are secreted; these molecules cause or at least contribute to the accumulation of intracellular cholesterol. This chain of events may explain the relationship between cholesterol accumulation and inflammation. The primary sequence of events in this chain is related to inflammatory response rather than cholesterol accumulation.
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White MJV, Chinea LE, Pilling D, Gomer RH. Protease activated-receptor 2 is necessary for neutrophil chemorepulsion induced by trypsin, tryptase, or dipeptidyl peptidase IV. J Leukoc Biol 2017; 103:119-128. [PMID: 29345066 DOI: 10.1002/jlb.3a0717-308r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/22/2017] [Accepted: 10/12/2017] [Indexed: 12/15/2022] Open
Abstract
Compared to neutrophil chemoattractants, relatively little is known about the mechanism neutrophils use to respond to chemorepellents. We previously found that the soluble extracellular protein dipeptidyl peptidase IV (DPPIV) is a neutrophil chemorepellent. In this report, we show that an inhibitor of the protease activated receptor 2 (PAR2) blocks DPPIV-induced human neutrophil chemorepulsion, and that PAR2 agonists such as trypsin, tryptase, 2f-LIGRL, SLIGKV, and AC55541 induce human neutrophil chemorepulsion. Several PAR2 agonists in turn block the ability of the chemoattractant fMLP to attract neutrophils. Compared to neutrophils from male and female C57BL/6 mice, neutrophils from male and female mice lacking PAR2 are insensitive to the chemorepulsive effects of DPPIV or PAR2 agonists. Acute respiratory distress syndrome (ARDS) involves an insult-mediated influx of neutrophils into the lungs. In a mouse model of ARDS, aspiration of PAR2 agonists starting 24 h after an insult reduce neutrophil numbers in the bronchoalveolar lavage (BAL) fluid, as well as the post-BAL lung tissue. Together, these results indicate that the PAR2 receptor mediates DPPIV-induced chemorepulsion, and that PAR2 agonists might be useful to induce neutrophil chemorepulsion.
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Affiliation(s)
- Michael J V White
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Luis E Chinea
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Darrell Pilling
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Richard H Gomer
- Department of Biology, Texas A&M University, College Station, Texas, USA
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Cho KS, Lee EJ, Kim JN, Choi JW, Kim HY, Han SH, Ryu JH, Cheong JH, Shin CY, Kwon KJ. Proteinase 3 Induces Neuronal Cell Death Through Microglial Activation. Neurochem Res 2015; 40:2242-51. [PMID: 26349766 DOI: 10.1007/s11064-015-1714-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 07/30/2015] [Accepted: 08/28/2015] [Indexed: 01/29/2023]
Abstract
Proteinase 3 (PR3) is released from neutrophil granules and is involved in the inflammatory process. PR3 is implicated in antimicrobial defense and cell death, but the exact role of PR3 in the brain is less defined. Microglia is the major immune effector cells in the CNS and is activated by brain injury. In the present study, the effect of PR3 on glial activation was investigated. Microglial activation was assessed by the intracellular level of reactive oxygen species and expression of inflammatory cytokines. The conditioned media from activated microglia by PR3 was used for measuring the neurotoxic effects of PR3-stimulated microglia. The effects of PR3 in vivo were measured by microinjecting PR3 into the rat brain. Herein we show that PR3 increased the inflammatory responses including the intracellular ROS and pro-inflammatory cytokine production in rat primary microglia. Conditioned media from PR3-treated microglia induced neuronal cell death in a concentration dependent manner. Furthermore, microinjected PR3 into the striatum of the rat brain induced microglial activation and neuronal cell death. Interestingly treatment with anti-PR3 monoclonal antibody and protease inhibitors ameliorated microglial activation induced by PR3 in primary microglia and striatum, which also prevented neuronal cell death in both conditions. The data presented here suggest that PR3 is a direct modulator of microglial activation and causes neuronal death through the augmentation of inflammatory responses. We suggest that PR3 could be a new modulator of neuroinflammation, and blocking PR3 would be a promising novel therapeutic target for neuroinflammatory disease such as stroke and Alzheimer's disease.
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Affiliation(s)
- Kyu Suk Cho
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea
| | - Eun Joo Lee
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea
| | - Jung Nam Kim
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea
| | - Ji Woong Choi
- Department of Pharmacology, College of Pharmacy, Gachon University, Incheon, Korea
| | - Hahn Young Kim
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea.,Department of Neurology, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, Seoul, Korea
| | - Seol-Heui Han
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea.,Department of Neurology, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, Seoul, Korea
| | - Jong Hoon Ryu
- Department of Oriental Pharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul, Korea
| | - Jae Hoon Cheong
- Department of Pharmacy, College of Pharmacy, Sahmyook University, Seoul, Korea
| | - Chan Young Shin
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea
| | - Kyoung Ja Kwon
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea.
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Berthold T, Schubert N, Muschter S, Rohr M, Wesche J, Reil A, Bux J, Bakchoul T, Greinacher A. HNA antibody-mediated neutrophil aggregation is dependent on serine protease activity. Vox Sang 2015; 109:366-74. [PMID: 26084778 DOI: 10.1111/vox.12292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 03/31/2015] [Accepted: 04/01/2015] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND OBJECTIVES Transfusion-related acute lung injury (TRALI) is often caused by antibodies against human neutrophil alloantigen-2 (HNA-2) and HNA-3a. Neutrophil aggregation is considered as a major cause of TRALI, but little is known about how HNA antibodies initiate this process. We explored mechanisms involved in neutrophil aggregation induced by HNA-2 and HNA-3a antibodies. MATERIALS AND METHODS Isolated neutrophils were pretreated with broad-spectrum or specific inhibitors against different cell functions or proteases. Granulocyte agglutination test (GAT) was performed with serially diluted anti-HNA-2 and anti-HNA-3a plasmas or control plasma, and reactivity was evaluated microscopically. Reactive oxygen species (ROS) production in neutrophils was investigated using a lucigenin-based chemiluminescence assay. RESULTS HNA-2 and HNA-3a antibody-mediated neutrophil aggregation was inhibited by pretreatment with formaldehyde, iodoacetamide and the serine protease inhibitors Pefabloc-SC, N-p-tosyl-L-phenylalanine chloromethyl ketone (TPCK) and Nα-tosyl-L-lysine chloromethyl ketone hydrochloride (TLCK). In contrast, inhibition of actin polymerization, respiratory burst, cysteine proteases, metalloproteases or aspartic proteases did not affect neutrophil aggregation. Furthermore, HNA-3a antibodies did not directly cause ROS production in neutrophils. CONCLUSION Aggregation of neutrophils induced by HNA-2 and HNA-3a antibodies is an active process and depends on trypsin- or chymotrypsin-like serine proteases but is not dependent on the production of ROS. These findings may open new prospects for the pharmacologic prevention of neutrophil-associated acute lung injury.
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Affiliation(s)
- T Berthold
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
| | - N Schubert
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
| | - S Muschter
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
| | - M Rohr
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
| | - J Wesche
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
| | - A Reil
- Deutsches Rotes Kreuz - Blutspendedienst West, Hagen, Germany
| | - J Bux
- Ruhr Universität Bochum, Bochum, Germany
| | - T Bakchoul
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
| | - A Greinacher
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
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Alam J, Kim YC, Choi Y. Potential role of bacterial infection in autoimmune diseases: a new aspect of molecular mimicry. Immune Netw 2014; 14:7-13. [PMID: 24605075 PMCID: PMC3942510 DOI: 10.4110/in.2014.14.1.7] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 01/02/2014] [Accepted: 01/13/2014] [Indexed: 12/20/2022] Open
Abstract
Molecular mimicry is an attractive mechanism for triggering autoimmunity. In this review, we explore the potential role of evolutionary conserved bacterial proteins in the production of autoantibodies with focus on granulomatosis with polyangiitis (GPA) and rheumatoid arthritis (RA). Seven autoantigens characterized in GPA and RA were BLASTed against a bacterial protein database. Of the seven autoantigens, proteinase 3, type II collagen, binding immunoglobulin protein, glucose-6-phosphate isomerase, α-enolase, and heterogeneous nuclear ribonuclear protein have well-conserved bacterial orthologs. Importantly, those bacterial orthologs are also found in human-associated bacteria. The wide distribution of the highly conserved stress proteins or enzymes among the members of the normal flora and common infectious microorganisms raises a new question on how cross-reactive autoantibodies are not produced during the immune response to these bacteria in most healthy people. Understanding the mechanisms that deselect auto-reactive B cell clones during the germinal center reaction to homologous foreign antigens may provide a novel strategy to treat autoimmune diseases.
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Affiliation(s)
- Jehan Alam
- Department of Immunology and Molecular Microbiology, Dental research Institute, Seoul National University School of Dentistry, Seoul 110-749, Korea
| | - Yong Chul Kim
- Department of Immunology and Molecular Microbiology, Dental research Institute, Seoul National University School of Dentistry, Seoul 110-749, Korea
| | - Youngnim Choi
- Department of Immunology and Molecular Microbiology, Dental research Institute, Seoul National University School of Dentistry, Seoul 110-749, Korea
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Mechanisms of IL-8 suppression by Treponema denticola in gingival epithelial cells. Immunol Cell Biol 2013; 92:139-47. [PMID: 24296811 DOI: 10.1038/icb.2013.80] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 10/04/2013] [Accepted: 10/15/2013] [Indexed: 01/05/2023]
Abstract
The purpose of this study was to investigate the mechanism(s) of interleukin (IL)-8 suppression by Treponema denticola, one of the major periodontal pathogens, in gingival epithelial cells. Immortalized human gingival epithelial HOK-16B cells were infected with wild-type (WT), dentilisin-deficient (K1) or flagellin-deficient (flgE) T. denticola in the presence or absence of 2% human serum for 24 h. The levels of IL-8 expression were measured with real-time reverse transcription PCR and ELISA. In the absence of human serum, the WT and flgE, but not K1, substantially reduced not only the levels of IL-8 protein but also of IL-8 mRNA. Such downregulation of IL-8 mRNA was independent of bacterial invasion. Degradation of cytokine mixture by the WT, K1 and flgE revealed dentilisin-dependent preferential degradation of tumor necrosis factor (TNF)-α, an IL-8-inducing cytokine. WT and flgE significantly decreased the levels of TNFα secreted by HOK-16B cells, suggesting modulation of IL-8 through dentilisin-mediated degradation of TNFα. The addition of human serum to the culture potentiated the suppressive effect of T. denticola, resulting in substantial reductions of IL-8 and TNFα levels, even by K1. The serum-dependent effects of T. denticola were attributed to its ability to suppress the accumulation of intracellular reactive-oxygen species (ROS), a group of ubiquitous signaling molecules. Pretreatment with an antioxidant suppressed TNFα-induced IL-8 expression, confirming the role of ROS in TNFα signaling. Collectively, T. denticola targeted a key inflammatory cytokine and its signaling molecule to modulate the host innate immune response, which provides a new insight into modulation of host immunity by a periodontal pathogen.
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Schreiber A, Kettritz R. The neutrophil in antineutrophil cytoplasmic autoantibody-associated vasculitis. J Leukoc Biol 2013; 94:623-31. [DOI: 10.1189/jlb.1012525] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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