Oxidation of calmodulin-dependent protein kinase II (ox-CaMKII) by ROS has been associated with asthma. However, the contribution of ox-CaMKII to the development of asthma remains to be fully characterized. Here, we tested the effect of ox-CaMKII on IgE-mediated mast cell activation in an allergen-induced mouse model of asthma using oxidant-resistant CaMKII MMVVδ knockin (MMVVδ) mice. Compared with WT mice, the allergen-challenged MMVVδ mice displayed less airway hyperresponsiveness (AHR) and inflammation. These MMVVδ mice exhibited reduced levels of ROS and diminished recruitment of mast cells to the lungs. OVA-activated bone marrow–derived mast cells (BMMCs) from MMVVδ mice showed a significant inhibition of ROS and ox-CaMKII expression. ROS generation was dependent on intracellular Ca2+ concentration in BMMCs. Importantly, OVA-activated MMVVδ BMMCs had suppressed degranulation, histamine release, leukotriene C4, and IL-13 expression. Adoptive transfer of WT, but not MMVVδ, BMMCs, reversed the alleviated AHR and inflammation in allergen-challenged MMVVδ mice. The CaMKII inhibitor KN-93 significantly suppressed IgE-mediated mast cell activation and asthma. These studies support a critical but previously unrecognized role of ox-CaMKII in mast cells that promotes asthma and suggest that therapies to reduce ox-CaMKII may be a novel approach for asthma.
Jingjing Qu, Danh C. Do, Yufeng Zhou, Elizabeth Luczak, Wayne Mitzner, Mark E. Anderson, Peisong Gao
The epigenome provides a substrate through which environmental exposures can exert their effects on gene expression and disease risk, but the relative importance of epigenetic variation on human disease onset and progression is poorly characterized. Asthma is a heterogeneous disease of the airways, for which both onset and clinical course result from interactions between host genotype and environmental exposures, yet little is known about the molecular mechanisms for these interactions. We assessed genome-wide DNA methylation using the Infinium Human Methylation 450K Bead Chip and characterized the transcriptome by RNA sequencing in primary airway epithelial cells from 74 asthmatic and 41 nonasthmatic adults. Asthma status was based on doctor’s diagnosis and current medication use. Genotyping was performed using various Illumina platforms. Our study revealed a regulatory locus on chromosome 17q12-21 associated with asthma risk and epigenetic signatures of specific asthma endotypes and molecular networks. Overall, these data support a central role for DNA methylation in lung cells, which promotes distinct molecular pathways of asthma pathogenesis and modulates the effects of genetic variation on disease risk and clinical heterogeneity.
Jessie Nicodemus-Johnson, Rachel A. Myers, Noburu J. Sakabe, Debora R. Sobreira, Douglas K. Hogarth, Edward T. Naureckas, Anne I. Sperling, Julian Solway, Steven R. White, Marcelo A. Nobrega, Dan L. Nicolae, Yoav Gilad, Carole Ober
Maladaptive epithelial repair from chronic injury is a common feature in fibrotic diseases, which in turn activates a pathogenic fibroblast response that produces excessive matrix deposition. Dysregulated microRNAs (miRs) can regulate expression of multiple genes and fundamentally alter cellular phenotypes during fibrosis. Although several miRs have been shown to be associated with lung fibrosis, the mechanisms by which miRs modulate epithelial behavior in lung fibrosis are lacking. Here, we identified miR-323a-3p to be downregulated in the epithelium of lungs with bronchiolitis obliterans syndrome (BOS) after lung transplantation, idiopathic pulmonary fibrosis (IPF), and murine bleomycin-induced fibrosis. Antagomirs for miR-323a-3p augment, and mimics suppress, murine lung fibrosis after bleomycin injury, indicating that this miR may govern profibrotic signals. We demonstrate that miR-323a-3p attenuates TGF-α and TGF-β signaling by directly targeting key adaptors in these important fibrogenic pathways. Moreover, miR-323a-3p lowers caspase-3 expression, thereby limiting programmed cell death from inducers of apoptosis and ER stress. Finally, we find that epithelial expression of miR-323a-3p modulates inhibitory crosstalk with fibroblasts. These studies demonstrate that miR-323a-3p has a central role in lung fibrosis that spans across murine and human disease, and downregulated expression by the lung epithelium releases inhibition of various profibrotic pathways to promote fibroproliferation.
Lingyin Ge, David M. Habiel, Phil M. Hansbro, Richard Y. Kim, Sina A. Gharib, Jeffery D. Edelman, Melanie Königshoff, Tanyalak Parimon, Rena Brauer, Ying Huang, Jenieke Allen, Dianhua Jiang, Adrianne A. Kurkciyan, Takako Mizuno, Barry R. Stripp, Paul W. Noble, Cory M. Hogaboam, Peter Chen
The stasis of mucus secretions in the lungs of cystic fibrosis (CF) patients leads to recurrent infections and pulmonary exacerbations, resulting in decreased survival. Prior studies have assessed the biochemical and biophysical features of airway mucus in individuals with CF. However, these measurements are unable to probe mucus structure on microscopic length scales relevant to key players in the progression of CF-related lung disease, namely, viruses, bacteria, and neutrophils. In this study, we quantitatively determined sputum microstructure based on the diffusion of muco-inert nanoparticle probes in CF sputum and found that a reduction in sputum mesh pore size is characteristic of CF patients with reduced lung function, as indicated by measured FEV1. We also discovered that the effect of ex vivo treatment of CF sputum with rhDNase I (Pulmozyme) on microstructure is dependent upon the time interval between the most recent inhaled rhDNase I treatment and the sample collection. Microstructure of mucus may serve as a marker for the extent of CF lung disease and as a parameter for assessing the effectiveness of mucus-altering agents.
Gregg A. Duncan, James Jung, Andrea Joseph, Abigail L. Thaxton, Natalie E. West, Michael P. Boyle, Justin Hanes, Jung Soo Suk
Chronic inflammation with mucous metaplasia and airway remodeling are hallmarks of allergic asthma, and these outcomes have been associated with enhanced expression and activation of EGFR signaling. Here, we demonstrate enhanced expression of EGFR ligands such as amphiregulin as well as constitutive EGFR activation in cultured nasal epithelial cells from asthmatic subjects compared with nonasthmatic controls and in lung tissues of mice during house dust mite–induced (HDM-induced) allergic inflammation. EGFR activation was associated with cysteine oxidation within EGFR and the nonreceptor tyrosine kinase Src, and both amphiregulin production and oxidative EGFR activation were diminished by pharmacologic or genetic inhibition of the epithelial NADPH oxidase dual oxidase 1 (DUOX1). DUOX1 deficiency also attenuated several EGFR-dependent features of HDM-induced allergic airway inflammation, including neutrophilic inflammation, type 2 cytokine production (IL-33, IL-13), mucous metaplasia, subepithelial fibrosis, and central airway resistance. Moreover, targeted inhibition of airway DUOX1 in mice with previously established HDM-induced allergic inflammation, by intratracheal administration of DUOX1-targeted siRNA or pharmacological NADPH oxidase inhibitors, reversed most of these outcomes. Our findings indicate an important function for DUOX1 in allergic inflammation related to persistent EGFR activation and suggest that DUOX1 targeting may represent an attractive strategy in asthma management.
Aida Habibovic, Milena Hristova, David E. Heppner, Karamatullah Danyal, Jennifer L. Ather, Yvonne M.W. Janssen-Heininger, Charles G. Irvin, Matthew E. Poynter, Lennart K. Lundblad, Anne E. Dixon, Miklos Geiszt, Albert van der Vliet
Alveolar epithelial cell (AEC) dysfunction underlies the pathogenesis of pulmonary fibrosis in Hermansky-Pudlak syndrome (HPS) and other genetic syndromes associated with interstitial lung disease; however, mechanisms linking AEC dysfunction and fibrotic remodeling are incompletely understood. Since increased macrophage recruitment precedes pulmonary fibrosis in HPS, we investigated whether crosstalk between AECs and macrophages determines fibrotic susceptibility. We found that AECs from HPS mice produce excessive MCP-1, which was associated with increased macrophages in the lungs of unchallenged HPS mice. Blocking MCP-1/CCR2 signaling in HPS mice with genetic deficiency of CCR2 or targeted deletion of MCP-1 in AECs normalized macrophage recruitment, decreased AEC apoptosis, and reduced lung fibrosis in these mice following treatment with low-dose bleomycin. We observed increased TGF-β production by HPS macrophages, which was eliminated by CCR2 deletion. Selective deletion of TGF-β in myeloid cells or of TGF-β signaling in AECs through deletion of TGFBR2 protected HPS mice from AEC apoptosis and bleomycin-induced fibrosis. Together, these data reveal a feedback loop in which increased MCP-1 production by dysfunctional AECs results in recruitment and activation of lung macrophages that produce TGF-β, thus amplifying the fibrotic cascade through AEC apoptosis and stimulation of fibrotic remodeling.
Lisa R. Young, Peter M. Gulleman, Chelsi W. Short, Harikrishna Tanjore, Taylor Sherrill, Aidong Qi, Andrew P. McBride, Rinat Zaynagetdinov, John T. Benjamin, William E. Lawson, Sergey V. Novitskiy, Timothy S. Blackwell
Adaptive changes in the genome of a locally predominant clinical isolate of the multidrug-resistant
Danielle Ahn, Hernán Peñaloza, Zheng Wang, Matthew Wickersham, Dane Parker, Purvi Patel, Antonius Koller, Emily I. Chen, Susan M. Bueno, Anne-Catrin Uhlemann, Alice Prince
Lymphangioleiomyomatosis (LAM) is a rare lung disease of women that leads to progressive cyst formation and accelerated loss of pulmonary function. Neoplastic smooth muscle cells from an unknown source metastasize to the lung and drive destructive remodeling. Given the role of NK cells in immune surveillance, we postulated that NK cell activating receptors and their cognate ligands are involved in LAM pathogenesis. We found that ligands for the NKG2D activating receptor UL-16 binding protein 2 (ULBP2) and ULBP3 are localized in cystic LAM lesions and pulmonary nodules. We found elevated soluble serum ULBP2 (mean = 575 pg/ml ± 142) in 50 of 100 subjects and ULBP3 in 30 of 100 (mean = 8,300 pg/ml ± 1,515) subjects. LAM patients had fewer circulating NKG2D+ NK cells and decreased NKG2D surface expression. Lung function decline was associated with soluble NKG2D ligand (sNKG2DL) detection. The greatest rate of decline forced expiratory volume in 1 second (FEV1, –124 ± 30 ml/year) in the 48 months after enrollment (NHLBI LAM Registry) occurred in patients expressing both ULBP2 and ULBP3, whereas patients with undetectable sNKG2DL levels had the lowest rate of FEV1 decline (–32.7 ± 10 ml/year). These data suggest a role for NK cells, sNKG2DL, and the innate immune system in LAM pathogenesis.
Andrew R. Osterburg, Rebecca L. Nelson, Benyamin Z. Yaniv, Rachel Foot, Walter R.F. Donica, Madison A. Nashu, Huan Liu, Kathryn A. Wikenheiser-Brokamp, Joel Moss, Nishant Gupta, Francis X. McCormack, Michael T. Borchers
Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in the US. The majority of COPD patients have symptoms of chronic bronchitis, which lacks specific therapies. A major impediment to therapeutic development has been the absence of animal models that recapitulate key clinical and pathologic features of human disease. Ferrets are well suited for the investigation of the significance of respiratory diseases, given prior data indicating similarities to human airway physiology and submucosal gland distribution. Here, we exposed ferrets to chronic cigarette smoke and found them to approximate complex clinical features of human COPD. Unlike mice, which develop solely emphysema, smoke-exposed ferrets exhibited markedly higher numbers of early-morning spontaneous coughs and sporadic infectious exacerbations as well as a higher level of airway obstruction accompanied by goblet cell metaplasia/hyperplasia and increased mucus expression in small airways, indicative of chronic bronchitis and bronchiolitis. Overall, we demonstrate the first COPD animal model exhibiting clinical and pathologic features of chronic bronchitis to our knowledge, providing a key advance that will greatly facilitate the preclinical development of novel treatments for this disease.
S. Vamsee Raju, Hyunki Kim, Stephen A. Byzek, Li Ping Tang, John E. Trombley, Patricia Jackson, Lawrence Rasmussen, J. Michael Wells, Emily Falk Libby, Erik Dohm, Lindy Winter, Sharon L. Samuel, Kurt R. Zinn, J. Edwin Blalock, Trenton R. Schoeb, Mark T. Dransfield, Steven M. Rowe
Telomeres are short in type II alveolar epithelial cells (AECs) of patients with idiopathic pulmonary fibrosis (IPF). Whether dysfunctional telomeres contribute directly to development of lung fibrosis remains unknown. The objective of this study was to investigate whether telomere dysfunction in type II AECs, mediated by deletion of the telomere shelterin protein TRF1, leads to pulmonary fibrosis in mice (
Ram P. Naikawadi, Supparerk Disayabutr, Benat Mallavia, Matthew L. Donne, Gary Green, Janet L. La, Jason R. Rock, Mark R. Looney, Paul J. Wolters
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