Browsing by Author "Lugogo, Njira L"
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Item Open Access Airway fibroblasts in asthma manifest an invasive phenotype.(American journal of respiratory and critical care medicine, 2011-06) Ingram, Jennifer L; Huggins, Molly J; Church, Tony D; Li, Yuejuan; Francisco, Dave C; Degan, Simone; Firszt, Rafael; Beaver, Denise M; Lugogo, Njira L; Wang, Ying; Sunday, Mary E; Noble, Paul W; Kraft, MonicaRationale
Invasive cell phenotypes have been demonstrated in malignant transformation, but not in other diseases, such as asthma. Cellular invasiveness is thought to be mediated by transforming growth factor (TGF)-β1 and matrix metalloproteinases (MMPs). IL-13 is a key T(H)2 cytokine that directs many features of airway remodeling through TGF-β1 and MMPs.Objectives
We hypothesized that, in human asthma, IL-13 stimulates increased airway fibroblast invasiveness via TGF-β1 and MMPs in asthma compared with normal controls.Methods
Fibroblasts were cultured from endobronchial biopsies in 20 subjects with mild asthma (FEV(1): 90 ± 3.6% pred) and 17 normal control subjects (FEV(1): 102 ± 2.9% pred) who underwent bronchoscopy. Airway fibroblast invasiveness was investigated using Matrigel chambers. IL-13 or IL-13 with TGF-β1 neutralizing antibody or pan-MMP inhibitor (GM6001) was added to the lower chamber as a chemoattractant. Flow cytometry and immunohistochemistry were performed in a subset of subjects to evaluate IL-13 receptor levels.Measurements and main results
IL-13 significantly stimulated invasion in asthmatic airway fibroblasts, compared with normal control subjects. Inhibitors of both TGF-β1 and MMPs blocked IL-13-induced invasion in asthma, but had no effect in normal control subjects. At baseline, in airway tissue, IL-13 receptors were expressed in significantly higher levels in asthma, compared with normal control subjects. In airway fibroblasts, baseline IL-13Rα2 was reduced in asthma compared with normal control subjects.Conclusions
IL-13 potentiates airway fibroblast invasion through a mechanism involving TGF-β1 and MMPs. IL-13 receptor subunits are differentially expressed in asthma. These effects may result in IL-13-directed airway remodeling in asthma.Item Open Access Effect of the S-nitrosoglutathione reductase inhibitor N6022 on bronchial hyperreactivity in asthma.(Immunity, inflammation and disease, 2018-06) Que, Loretta G; Yang, Zhonghui; Lugogo, Njira L; Katial, Rohit K; Shoemaker, Steven A; Troha, Janice M; Rodman, David M; Tighe, Robert M; Kraft, MonicaRationale
Patients with asthma demonstrate depletion of the endogenous bronchodilator GSNO and upregulation of GSNOR.Objectives
An exploratory proof of concept clinical study of N6022 in mild asthma to determine the potential bronchoprotective effects of GSNOR inhibition. Mechanistic studies aimed to provide translational evidence of effect.Methods
Fourteen mild asthma patients were treated with intravenous N6022 (5 mg) or placebo and observed for 7 days, with repeated assessments of the provocative dose of methacholine causing a 20% fall in FEV1 (methacholine PC20 FEV1), followed by a washout period and crossover treatment and observation. In vitro studies in isolated eosinophils investigated the effect of GSNO and N6022 on apoptosis.Measurements and main results
This was a negative trial as it failed to reach its primary endpoint, which was change from baseline in methacholine PC20 FEV1 at 24 h. However, our exploratory analysis demonstrated significantly more two dose-doubling increases in PC20 FEV1 for N6022 compared with placebo (21% vs 6%, P < 0.05) over the 7-day observation period. Furthermore, a significant treatment effect was observed in the change in PC20 FEV1 from baseline averaged over the 7-day observation period (mean change: +0.82 mg/ml [N6022] from 1.34 mg/ml [baseline] vs -0.18 mg/ml [placebo] from 1.16 mg/ml [baseline], P = 0.023). N6022 was well tolerated in mild asthmatics. In vitro studies demonstrated enhanced eosinophilic apoptosis with N6022.Conclusions
In this early phase exploratory proof of concept trial in asthma, N6022 did not significantly alter methacholine PC20 FEV1 at 24 h, but did have a treatment effect at 7 days compared to baseline. Further investigation of the efficacy of S-nitrosoglutathione reductase inhibition in a patient population with eosinophilic asthma is warranted.Item Open Access Role of Matrix Metalloproteinases-1 and -2 in Interleukin-13-Suppressed Elastin in Airway Fibroblasts in Asthma.(American journal of respiratory cell and molecular biology, 2016-01) Ingram, Jennifer L; Slade, David; Church, Tony D; Francisco, Dave; Heck, Karissa; Sigmon, R Wesley; Ghio, Michael; Murillo, Anays; Firszt, Rafael; Lugogo, Njira L; Que, Loretta; Sunday, Mary E; Kraft, MonicaElastin synthesis and degradation in the airway and lung parenchyma contribute to airway mechanics, including airway patency and elastic recoil. IL-13 mediates many features of asthma pathobiology, including airway remodeling, but the effects of IL-13 on elastin architecture in the airway wall are not known. We hypothesized that IL-13 modulates elastin expression in airway fibroblasts from subjects with allergic asthma. Twenty-five subjects with mild asthma (FEV1, 89 ± 3% predicted) and 30 normal control subjects (FEV1, 102 ± 2% predicted) underwent bronchoscopy with endobronchial biopsy. Elastic fibers were visualized in airway biopsy specimens using Weigert's resorcin-fuchsin elastic stain. Airway fibroblasts were exposed to IL-13; a pan-matrix metalloproteinase (MMP) inhibitor (GM6001); specific inhibitors to MMP-1, -2, -3, and -8; and combinations of IL-13 with MMP inhibitors in separate conditions in serum-free media for 48 hours. Elastin (ELN) expression as well as MMP secretion and activity were quantified. Results of this study show that elastic fiber staining of airway biopsy tissue was significantly associated with methacholine PC20 (i.e., the provocative concentration of methacholine resulting in a 20% fall in FEV1 levels) in patients with asthma. IL-13 significantly suppressed ELN expression in asthmatic airway fibroblasts as compared with normal control fibroblasts. The effect of IL-13 on ELN expression was significantly correlated with postbronchodilator FEV1/FVC in patients with asthma. MMP inhibition significantly stimulated ELN expression in patients with asthma as compared with normal control subjects. Specific inhibition of MMP-1 and MMP-2, but not MMP-3 or MMP-8, reversed the IL-13-induced suppression of ELN expression. In asthma, MMP-1 and MMP-2 mediate IL-13-induced suppression of ELN expression in airway fibroblasts.Item Open Access SHP-1 as a critical regulator of Mycoplasma pneumoniae-induced inflammation in human asthmatic airway epithelial cells.(Journal of immunology (Baltimore, Md. : 1950), 2012-04) Wang, Ying; Zhu, Zhou; Church, Tony D; Lugogo, Njira L; Que, Loretta G; Francisco, Dave; Ingram, Jennifer L; Huggins, Molly; Beaver, Denise M; Wright, Jo Rae; Kraft, MonicaAsthma is a chronic inflammatory disease in which airway epithelial cells are the first line of defense against exposure of the airway to infectious agents. Src homology protein (SHP)-1, a protein tyrosine phosphatase, is a negative regulator of signaling pathways that are critical to the development of asthma and host defense. We hypothesize that SHP-1 function is defective in asthma, contributing to the increased inflammatory response induced by Mycoplasma pneumoniae, a pathogen known to exacerbate asthma. M. pneumoniae significantly activated SHP-1 in airway epithelial cells collected from nonasthmatic subjects by bronchoscopy with airway brushing but not in cells from asthmatic subjects. In asthmatic airway epithelial cells, M. pneumoniae induced significant PI3K/Akt phosphorylation, NF-κB activation, and IL-8 production compared with nonasthmatic cells, which were reversed by SHP-1 overexpression. Conversely, SHP-1 knockdown significantly increased IL-8 production and PI3K/Akt and NF-κB activation in the setting of M. pneumoniae infection in nonasthmatic cells, but it did not exacerbate these three parameters already activated in asthmatic cells. Thus, SHP-1 plays a critical role in abrogating M. pneumoniae-induced IL-8 production in nonasthmatic airway epithelial cells through inhibition of PI3K/Akt and NF-κB activity, but it is defective in asthma, resulting in an enhanced inflammatory response to infection.Item Open Access Surfactant protein A is defective in abrogating inflammation in asthma.(American journal of physiology. Lung cellular and molecular physiology, 2011-10) Wang, Ying; Voelker, Dennis R; Lugogo, Njira L; Wang, Guirong; Floros, Joanna; Ingram, Jennifer L; Chu, Hong Wei; Church, Tony D; Kandasamy, Pitchaimani; Fertel, Daniel; Wright, Jo Rae; Kraft, MonicaSurfactant protein A (SP-A) regulates a variety of immune cell functions. We determined the ability of SP-A derived from normal and asthmatic subjects to modulate the inflammatory response elicited by Mycoplasma pneumoniae, a pathogen known to exacerbate asthma. Fourteen asthmatic and 10 normal control subjects underwent bronchoscopy with airway brushing and bronchoalveolar lavage (BAL). Total SP-A was extracted from BAL. The ratio of SP-A1 to total SP-A (SP-A1/SP-A) and the binding of total SP-A to M. pneumoniae membranes were determined. Airway epithelial cells from subjects were exposed to either normal or asthmatic SP-A before exposure to M. pneumoniae. IL-8 protein and MUC5AC mRNA were measured. Total BAL SP-A concentration did not differ between groups, but the percentage SP-A1 was significantly increased in BAL of asthmatic compared with normal subjects. SP-A1/SP-A significantly correlated with maximum binding of total SP-A to M. pneumoniae, but only in asthma. SP-A derived from asthmatic subjects did not significantly attenuate IL-8 and MUC5AC in the setting of M. pneumoniae infection compared with SP-A derived from normal subjects. We conclude that SP-A derived from asthmatic subjects does not abrogate inflammation effectively, and this dysfunction may be modulated by SP-A1/SP-A.