Abstract IL-33 levels and activity are differentially associated with Th1 and Th2 phenotypes. IL-33 mRNA is rapidly regulated but the fate of synthesized IL-33 protein is unknown. To assess the interplay between IL-33, IFN-γ, and IL-4 proteins, replication-deficient adenoviruses (AdV) were constructed for dual expression of IL-33 & IFN-γ or of IL-33 & IL-4. Combined IL-33 & IFN-γ or IL-33 & IL-4 effects were compared with similar AdV expression of each of these cytokines alone. Co-delivery of IL-33 & IFN-γ led to mutual suppression, and co-delivery of IL-33 & IL-4 led to mutual elevation of these proteins in cell culture and in vivo. Purified IFN-γ also attenuated IL-33 protein but not mRNA driven by the recombinant CMV promoter in AdV-IL-33-infected cells, suggesting that IFN-γ controls IL-33 protein degradation. Pharmacological inhibition, siRNA-mediated silencing, or gene deficiency of STAT1 potently upregulated IL-33 protein expression levels and attenuated the downregulating effect of IFN-γ on IL-33. Inhibition of caspase-1, -3, or -8 had minimal effect on IFN-γ-driven IL-33 protein downregulation. siRNA-mediated silencing of LMP2 proteasome subunit, which is known to be essential for IFN-γ-regulated antigen processing, also abrogated the effect of IFN-γ on IL-33. Thus, IL-33, IFN-γ, and IL-4 are engaged in a complex interplay, part of which involves IFN-γ-activated, caspase-independent, STAT1-mediated degradation of IL-33 protein through non-canonical use of LMP2 proteasome.
Idiopathic pulmonary fibrosis (IPF) poses challenges to understanding its underlying cellular and molecular mechanisms and the development of better therapies. Previous studies suggest a pathophysiological role for neuraminidase 1 (NEU1), an enzyme that removes terminal sialic acid from glycoproteins. We observed increased NEU1 expression in epithelial and endothelial cells, as well as fibroblasts, in the lungs of patients with IPF compared with healthy control lungs. Recombinant adenovirus-mediated gene delivery of NEU1 to cultured primary human cells elicited profound changes in cellular phenotypes. Small airway epithelial cell migration was impaired in wounding assays, whereas, in pulmonary microvascular endothelial cells, NEU1 overexpression strongly impacted global gene expression, increased T cell adhesion to endothelial monolayers, and disrupted endothelial capillary-like tube formation. NEU1 overexpression in fibroblasts provoked increased levels of collagen types I and III, substantial changes in global gene expression, and accelerated degradation of matrix metalloproteinase-14. Intratracheal instillation of NEU1 encoding, but not control adenovirus, induced lymphocyte accumulation in bronchoalveolar lavage samples and lung tissues and elevations of pulmonary transforming growth factor-β and collagen. The lymphocytes were predominantly T cells, with CD8 + cells exceeding CD4 + cells by nearly twofold. These combined data indicate that elevated NEU1 expression alters functional activities of distinct lung cell types in vitro and recapitulates lymphocytic infiltration and collagen accumulation in vivo, consistent with mechanisms implicated in lung fibrosis.
Event Abstract Back to Event IL-33 precursor and bleomycin synergize in inducing lymphocyte accumulation and fibrosis in the lungs Irina G. Luzina1, 2, Virginia Lockatell1, 2, Pavel Kopach1, Nevins W. Todd1, 2 and Sergei P. Atamas1, 2* 1 University of Maryland School of Medicine, United States 2 Baltimore VA Medical Center, United States We and others have previously found that precursor IL-33 (PRIL33) protein is biologically active without proteolytic activation. We reported that the levels of PRIL33 are substantially elevated in the lungs of patients with interstitial lung disease (ILD), which is associated with idiopathic pulmonary fibrosis and systemic sclerosis. PRIL33 remains intranuclear and promotes inflammation in a non-Th2 fashion by not engaging the mature IL-33 receptor T1/ST2. To further assess the biological role of the elevated expression of PRIL33 in ILD, intratracheal bleomycin injury to the lung, alone or in combination with recombinant adenovirus delivery of PRIL33, was used to model ILD in mice. Combined PRIL33 gene delivery and bleomycin challenge had a potentiating effect on pulmonary lymphocytosis; accumulation of collagen; expression of HSP70; and the levels of TGF-β, CCL6, MCP-1, and MIP-1α, with these combined effects significantly exceeding the sum of the effects of PRIL33 gene delivery or bleomycin challenge alone (p < 0.05). By contrast, the combined effects of PRIL33 expression and bleomycin on bronchoalveolar lavage counts of macrophages and neutrophils in these mice were additive of the effects of each of these factors alone. The Th2 cytokines IL-4, IL-5, and IL-13 were not part of this synergy, and gene deficiency of T1/ST2 did not affect the synergistic nature of the “double-hit” from PRIL33 expression and bleomycin injury. It was concluded that elevated PRIL33 expression in ILD is a likely contributor to inflammatory and fibrotic lung injury, and that this contribution is independent of the T1/ST2 receptor or Th2 cytokines. Keywords: interleukin-33, Inflammation, Fibrosis, Lung, Scleroderma, Systemic, Idiopathic Pulmonary Fibrosis Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Immune-mediated disease pathogenesis Citation: Luzina IG, Lockatell V, Kopach P, Todd NW and Atamas SP (2013). IL-33 precursor and bleomycin synergize in inducing lymphocyte accumulation and fibrosis in the lungs. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00859 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 18 Jun 2013; Published Online: 22 Aug 2013. * Correspondence: Dr. Sergei P Atamas, University of Maryland School of Medicine, Baltimore, Maryland, United States, satamas@umaryland.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Irina G Luzina Virginia Lockatell Pavel Kopach Nevins W Todd Sergei P Atamas Google Irina G Luzina Virginia Lockatell Pavel Kopach Nevins W Todd Sergei P Atamas Google Scholar Irina G Luzina Virginia Lockatell Pavel Kopach Nevins W Todd Sergei P Atamas PubMed Irina G Luzina Virginia Lockatell Pavel Kopach Nevins W Todd Sergei P Atamas Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.
Abstract IL-33 precursor (IL33PR) released from damaged cells is known to bind to the receptor T1/ST2 and activate cells in culture. However, we found that in patients with interstitial lung diseases (ILD) and in the bleomycin mouse model of lung injury, pulmonary expression of IL33PR is elevated intracellularly and intranuclearly. Recombinant adenoviral gene delivery of IL33PR to mouse lungs in vivo did not lead to IL-33 maturation and produced a phenotype that was strikingly different from that induced by mature IL33 (MIL33). IL33PR induced pulmonary lymphocytosis and neutrophilia, whereas MIL33 induced eosinophilia, goblet cell hyperplasia, and increases in Th2 cytokines. The effects of MIL33 were, but the effects of IL33PR were not, abrogated by gene deficiency of T1/ST2. When combined with bleomycin injury, IL33PR potentiated lymphocytosis, collagen accumulation, and the expression of proinflammatory and profibrotic cytokines TGF-β, IL-6, MCP-1, and MIP-1α in the lungs. Gene expression profiling in cultured fibroblasts and epithelial cells overexpressing IL33PR revealed 10 - 100 fold increases in HSP70 mRNA, further confirmed by RT-Q-PCR. Previous reports have associated HSP70 with ILD. Immunohistochemical analyses showed strong HSP70 protein increases in mice challenged with bleomycin, IL33PR gene delivery, and particularly in mice challenged with these factors combined. Thus, IL33PR promotes ILD by inducing proinflammatory and profibrotic cytokines and HSP70.
A 29-year-old man presented to our institution with acute, severe substernal chest pain. An ECG on arrival revealed 3mm ST-elevations in the lateral leads with reciprocal depressions in the inferior leads. Troponin-I was above assay (>50 ng/mL). Emergent coronary angiography showed normal coronary arteries, and left ventriculogram showed no wall motion abnormalities. A transthoracic echocardiogram showed normal biventricular size, wall thickness, and ejection fraction (EF). This was his fifth episode of chest pain over the past 10 years, consistent with prior presentations of ST-elevation myocardial infarction and angiographically normal coronary arteries. A prior cardiac magnetic resonance imaging (MRI, 6 years before the current presentation) revealed increased T2 signal intensity and subepicardial late gadolinium enhancement (LGE) in the septum, inferior, and inferolateral walls, suggestive of nonischemic acute myocardial injury. A repeat cardiac MRI during the current presentation showed mildly reduced biventricular systolic function (LVEF 52%, RVEF 36%), and again showed increased T2 signal intensity and subepicardial LGE involving the septum, inferior and inferolateral walls. The anterior and anterolateral walls were also now involved. Endomyocardial biopsy (EMB) showed focal interstitial fibrosis with no evidence of active myocarditis. On telemetry he was noted to have runs of non-sustained ventricular tachycardia (NSVT). Serologic evaluation was negative for parvovirus, cytomegalovirus, and Chagas disease. Erythrocyte sedimentation rate and C-reactive protein levels were normal. Genetic testing was performed at our newly established cardiovascular genetics program, which showed a pathogenic truncating mutation in the desmoplakin gene (DSP). DSP cardiomyopathy (CM) is an LV-predominant arrhythmogenic CM, which can present with episodic myocardial injury, and has a high disposition for ventricular arrhythmias with subepicardial LGE pattern often proceeding LV systolic dysfunction. A primary prevention implantable cardioverter-defibrillator was placed given extent of LGE and NSVT burden in the context of DSP variant. This case illustrates the importance of genetic testing in identifying rare CM phenotypes.
The mechanisms of interstitial lung disease (ILD) remain incompletely understood, although recent observations have suggested an important contribution by IL-33. Substantial elevations in IL-33 expression were found in the lungs of patients with idiopathic pulmonary fibrosis and scleroderma lung disease, as well as in the bleomycin injury mouse model. Most of the observed IL-33 expression was intracellular and intranuclear, suggesting involvement of the full-length (fl) protein, but not of the proteolytically processed mature IL-33 cytokine. The effects of flIL-33 on mouse lungs were assessed independently and in combination with bleomycin injury, using recombinant adenovirus-mediated gene delivery. Bleomycin-induced changes were not affected by gene deficiency of the IL-33 receptor T1/ST2. Combined flIL-33 expression and bleomycin injury exerted a synergistic effect on pulmonary lymphocyte and collagen accumulation, which could be explained by synergistic regulation of the cytokines transforming growth factor-β, IL-6, monocyte chemotactic protein-1, macrophage inflammatory protein\x{2013}1α, and tumor necrosis factor-α. By contrast, no increase in the levels of the Th2 cytokines IL-4, IL-5, or IL-13 was evident. Moreover, flIL-33 was found to increase the expression of several heat shock proteins (HSPs) significantly, and in particular HSP70, which is known to be associated with ILD. Thus, flIL-33 is a synergistic proinflammatory and profibrotic regulator that acts by stimulating the expression of several non-Th2 cytokines, and activates the expression of HSP70.
