| 1. |
- Hansson, Marit, et al.
(författare)
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Interleukin-22 produced by alveolar macrophages during activation of the innate immune response
- 2013
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Ingår i: Inflammation Research. - : Springer Science and Business Media LLC. - 1023-3830 .- 1420-908X. ; 62:6, s. 561-569
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Tidskriftsartikel (refereegranskat)abstract
- Objective and design Interleukin (IL)-22 is important for mucosal host defense. Whereas previous studies focus on lymphocytes as sources of IL-22, we determined whether IL-22 is produced by inflammatory cells in the lungs other than T-lymphocytes during the activation of the innate immune response. Material, methods and treatment Inflammatory cells in the lungs of Balb/c mice were primed by endotoxin (LPS, 10 μg) or peptidoglycan (PG, 40 μg) intranasally (3 days). After CD3 + cell depletion, lung homogenates were re-stimulated 24 h with LPS (100 ng/ml), PG (10 μg/ml), IL-23 (100 ng/ml) or vehicle. Human BAL macrophages were stimulated 24 h with PG (50 μg/ml) and IL-23 (100 ng/ml) or vehicle. The release of IL-22 was measured with ELISA and intracellular IL-22 with immunostaining. For statistics, either Dunnett or Students t test method was employed (n = 3–8). Results Re-stimulation in vitro increased concentrations of mouse IL-22 protein irrespective of priming in vivo. A majority of macrophages in mouse lung and BAL samples displayed immunostaining for IL-22. In analogy, human BAL macrophages released IL-22 protein, and a third of these cells displayed immunostaining for IL-22. Conclusions Alveolar macrophages can produce and release IL-22 during the activation of the innate immune response and thereby constitute a potentially important regulator of mucosal host defence in the lungs.
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| 2. |
- Henningsson, Louise, 1979, et al.
(författare)
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Interleukin-17A during local and systemic Staphylococcus aureus-induced arthritis in mice.
- 2010
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Ingår i: Infection and immunity. - 1098-5522. ; 78:9, s. 3783-90
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus aureus is one of the dominant pathogens that induce septic arthritis in immunocompromised hosts, e.g., patients suffering from rheumatoid arthritis treated with immunosuppressive drugs. S. aureus-induced arthritis leads to severe joint destruction and high mortality despite antibiotic treatment. Recently, interleukin-17A (IL-17A) has been discovered to be an important mediator of aseptic arthritis both in mice and humans, but its function in S. aureus-induced arthritis is largely unknown. Here, we investigated the role of IL-17A in host defense against arthritis following systemic and local S. aureus infection in vivo. IL-17A knockout mice and wild-type mice were inoculated systemically (intravenously) or locally (intra-articularly) with S. aureus. During systemic infection, IL-17A knockout mice lost significantly more weight than the wild-type mice did, but no differences were found in the mortality rate. The absence of IL-17A had no impact on clinical arthritis development but led to increased histopathological erosivity late during systemic S. aureus infection. Bacterial clearance in kidneys was increased in IL-17A knockout mice compared to the level in wild-type mice only 1 day after bacterial inoculation. During systemic S. aureus infection, serum IL-17F protein levels and mRNA levels in the lymph nodes were elevated in the IL-17A knockout mice compared to the level in wild-type mice. In contrast to systemic infection, the IL-17A knockout mice had increased synovitis and erosions and locally decreased clearance of bacteria 3 days after local bacterial inoculation. On the basis of these findings, we suggest that IL-17A is more important in local host defense than in systemic host defense against S. aureus-induced arthritis.
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| 3. |
- Prause, Olof, 1973, et al.
(författare)
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IL-17-producing T lymphocytes in lung tissue and in the bronchoalveolar space after exposure to endotoxin from Escherichia coli in vivo - effects of anti-inflammatory pharmacotherapy.
- 2009
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Ingår i: Pulmonary pharmacology & therapeutics. - : Elsevier BV. - 1094-5539. ; 22:3, s. 199-207
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Tidskriftsartikel (refereegranskat)abstract
- Interleukin (IL)-17 may play a critical role for the innate immune response in mammals. However, little is known about its production in T lymphocytes in comparison with other cells, in lung tissue and in the bronchoalveolar space in vivo. Even less is known about the effects of anti-inflammatory pharmacotherapy on this IL-17 production. In this study on mice we show that one single, intranasal exposure to endotoxin from Escherichia coli increases extracellular IL-17 protein in bronchoalveolar (BAL) samples during 3 days, and is accompanied by a local increase in neutrophils and other inflammatory cells. This endotoxin exposure also elevates IL-17 mRNA in lung tissue samples. Moreover, after endotoxin exposure, the absolute number of CD3-positive cells containing intracellular IL-17 protein is increased as well; from a moderate cell number in lung tissue samples and from virtually none in BAL samples; with the number in lung tissue exceeding that observed in BAL samples. Notably, we also demonstrate that among the cells that contain intracellular IL-17 protein after endotoxin exposure, the percentage of CD3-positive cells is similar to that of CD3-negative cells in lung tissue. In contrast, CD3-negative cells dominate among IL-17-containing cells in BAL samples. A high systemic dose of a glucocorticoid receptor agonist attenuates the endotoxin-induced increase in extracellular IL-17 protein in BAL samples, IL-17 mRNA in lung tissue samples, and in IL-17-containing CD3-positive cells in BAL and lung tissue samples. This is also true for the endotoxin-induced accumulation of neutrophils and other inflammatory BAL cells in vivo. A systemic dose of a calcineurin phosphatase inhibitor exerts a less complete and more selective effect on the endotoxin-induced increase in extracellular IL-17 protein and on neutrophils in BAL samples. In vitro, endotoxin also increases extracellular IL-17 protein in a co-culture of CD3-positive spleen cells and adherent mononuclear BAL cells; an increase that was inhibited by a glucocorticoid as well as by a calcineurin phosphatase inhibitor. In conclusion, endotoxin-induced IL-17 production and release from T lymphocytes originates from cells that reside in lung tissue and from cells that have been recruited to the bronchoalveolar space. In both compartments, there is also a substantial number of cells other than T lymphocytes that contain IL-17 after endotoxin exposure. The sustained IL-17 production from T lymphocytes and the associated neutrophil accumulation may be inhibited non-selectively through glucocorticoid receptor stimulation and more selectively through calcineurin phosphatase inhibition.
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| 4. |
- Silverpil, Elin, 1978, et al.
(författare)
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IL-17 in human asthma
- 2012
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Ingår i: Expert Review of Respiratory Medicine. - : Informa UK Limited. - 1747-6348 .- 1747-6356. ; 6:2, s. 173-186
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Tidskriftsartikel (refereegranskat)abstract
- Expert Rev. Respir. Med. 6(2), 173-186 (2012) Asthma is perceived as a heterogeneous disease with several clinical phenotypes and triggering factors. In general, cytokines from T-helper 2 cells are believed to be critical contributors of asthma. In recent years, IL-17, another T-helper lymphocyte-associated cytokine, has been put forward as another potentially important mediator of asthma. Currently, several drugs that target IL-17 signaling are being tested in clinical trials. With the aim to find whether there are any specific features of this heterogeneous disease that potentially could be relieved by the use of IL-17-targeting drugs, this review scrutinizes the evidence for an involvement of IL-17 in human asthma.
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| 5. |
- Silverpil, Elin, 1978, et al.
(författare)
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Impact of Interleukin-17 on Macrophage Phagocytosis of Apoptotic Neutrophils and Particles
- 2011
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Ingår i: Inflammation. - 0360-3997. ; 34:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- There is now substantial evidence that the cytokine interleukin-17 orchestrates the accumulation of neutrophils in mammals and thereby contributes to host defense. However, the role of IL-17 in controlling neutrophil turnover is not fully understood. Here, we demonstrate that IL-17 stimulates the apoptosis of mouse neutrophils and, simultaneously, the release of the microbicidal compound, myeloperoxidase. IL-17 also stimulates mouse macrophages to phagocytose aged neutrophils and latex beads, and it induces an increase in a soluble form of the phagocytic receptor, lectin-like oxidized low-density lipoprotein receptor-1 as well. In contrast, IL-17 does not markedly increase the release of the archetype neutrophil-recruiting cytokine, macrophage inflammatory protein-2 in mouse macrophages. Importantly, IL-17 also stimulates the phagocytosis of latex beads in human monocyte-derived macrophages. Thus, IL-17 bears the potential to control both phagocytosis and neutrophil turnover during activation of host defense.
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| 6. |
- Silverpil, Elin, 1978
(författare)
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Modulatory role of IL-17 in airway inflammation
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- IL-17 orchestrates the accumulation of neutrophils to sites of infection and the release of microbicidal substances, and therefore plays a critical role in the innate immune response to infection. IL-17 is also involved in certain chronic inflammatory diseases in which dysfunctional control of neutrophil accumulation and turnover constitutes an important pathogenic factor. This pro-inflammatory potential of IL-17 in host defence and in inflammatory diseases has been studied extensively. However, there is now also published evidence that IL-17 has more complex actions, including inflammation-resolving potential under certain conditions. With this in mind, the aims of this thesis were to investigate endogenous and exogenous methods to regulate the production of IL-17 and to elucidate the role that IL-17 plays in resolving ongoing inflammation. More specifically, we looked at whether the cells in the lung produce IL-17 after exposure to lipopolysaccharide (LPS) from the Gram-negative Escherichia coli bacteria, and whether anti-inflammatory pharmacotherapies could be used to regulate the production of IL-17 in these cells. We also examined whether IL-17 contributes to neutrophil turnover through the regulation of macrophage phagocytosis of apoptotic neutrophils. Finally, we investigated whether IL-17 down-regulates the release of the upstream regulator IL-23. We found that LPS induced sustained IL-17 production and release from T cells that reside in lung tissue and that are recruited to the bronchoalveolar space in a mouse model of acute inflammation in vivo. In addition, population of cells other than T cells contributed to IL-17 production in the lung tissues and in the bronchoalveolar space. LPS-induced IL-17 production from T cells in lung tissues and in the bronchoalveolar space was inhibited by the anti-inflammatory drug dexamethasone. Furthermore, we found that IL-17 stimulated macrophage phagocytosis of apoptotic neutrophils and particles, and induced neutrophil apoptosis in an in vitro study on isolated murine and human cells. Finally, we found that that IL-17 inhibited the release of the upstream regulator IL-23, both in the bronchoalveolar space in mice in vivo and in isolated human cells of the monocyte lineage. A major finding is that the production of IL-17 can be regulated exogenously by anti-inflammatory drugs and endogenously by an IL-17-induced feedback loop, which, in turn, may protect against excessive, IL-23-induced IL-17 signalling. In addition, we demonstrate that IL-17 has both pro-inflammatory and inflammation-resolving actions; IL-17 accumulates neutrophils after stimulation with LPS, while it also induces the phagocytosis of apoptotic neutrophils, thereby controlling the total turnover of neutrophils. That IL-17 induces the apoptosis of neutrophils and increases the phagocytosis of these cells indicates a potentially valuable strategy to mitigate conditions in which necrotic neutrophils are an important contributor to severe and sometimes life-threatening conditions, such as chronic lung allograft rejection and acute respiratory distress syndrome.
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| 7. |
- Silverpil, Elin, 1978, et al.
(författare)
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Negative feedback on IL-23 exerted by IL-17A during pulmonary inflammation
- 2013
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Ingår i: Innate Immunity. - : SAGE Publications. - 1753-4259 .- 1753-4267. ; 19:5, s. 479-492
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Tidskriftsartikel (refereegranskat)abstract
- It is now established that IL-17 has a broad pro-inflammatory potential in mammalian host defense, in inflammatory disease and in autoimmunity, whereas little is known about its anti-inflammatory potential and inhibitory feedback mechanisms. Here, we examined whether IL-17A can inhibit the extracellular release of IL-23 protein, the upstream regulator of IL-17A producing lymphocyte subsets, that is released from macrophages during pulmonary inflammation. We characterized the effect of IL-17A on IL-23 release in several models of pulmonary inflammation, evaluated the presence of IL-17 receptor A (RA) and C (RC) on human alveolar macrophages and assessed the role of the Rho family GTPase Rac1 as a mediator of the effect of IL-17A on the release of IL-23 protein. In a model of sepsis-induced pneumonia, intravenous exposure to Staphylococcus aureus caused higher IL-23 protein concentrations in cell-free bronchoalveolar lavage (BAL) samples from IL-17A knockout (KO) mice, compared with wild type (WT) control mice. In a model of Gram-negative airway infection, pre-treatment with a neutralizing anti-IL-17A Ab and subsequent intranasal (i.n.) exposure to LPS caused higher IL-23 and IL-17A protein concentrations in BAL samples compared with mice exposed to LPS, but pre-treated with an isotype control Ab. Moreover, i.n. exposure with IL-17A protein per se decreased IL- 23 protein concentrations in BAL samples. We detected IL-17RA and IL-17RC on human alveolar macrophages, and found that invitro stimulation of these cells with IL-17A protein, after exposure to LPS, decreased IL-23 protein in conditioned medium, but not IL-23 p19 or p40 mRNA. This study indicates that IL-17A can partially inhibit the release of IL-23 protein during pulmonary inflammation, presumably by stimulating the here demonstrated receptor units IL-17RA and IL-17RC on alveolar macrophages. Hypothetically, the demonstrated mechanism may serve as negative feedback to protect from excessive IL-17A signaling and to control antibacterial host defense once it is activated.
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