Chang Cheng

A Novel Antiinflammatory Role for Andrographolide in Asthma via Inhibition of the Nuclear Factor-κB Pathway

RATIONALE Persistent activation of nuclear factor (NF)-kappaB has been associated with the development of asthma. Andrographolide, the principal active component of the medicinal plant Andrographis paniculata, has been shown to inhibit NF-kappaB activity. OBJECTIVES We hypothesized that andrographolide may attenuate allergic asthma via inhibition of the NF-kappaB signaling pathway. METHODS BALB/c mice sensitized and challenged with ovalbumin (OVA) developed airway inflammation. Bronchoalveolar lavage fluid was assessed for total and differential cell counts, and cytokine and chemokine levels. Serum IgE levels were also determined. Lung tissues were examined for cell infiltration and mucus hypersecretion, and the expression of inflammatory biomarkers. Airway hyperresponsiveness was monitored by direct airway resistance analysis. MEASUREMENTS AND MAIN RESULTS Andrographolide dose-dependently inhibited OVA-induced increases in total cell count, eosinophil count, and IL-4, IL-5, and IL-13 levels recovered in bronchoalveolar lavage fluid, and reduced serum level of OVA-specific IgE. It attenuated OVA-induced lung tissue eosinophilia and airway mucus production, mRNA expression of E-selectin, chitinases, Muc5ac, and inducible nitric oxide synthase in lung tissues, and airway hyperresponsiveness to methacholine. In normal human bronchial epithelial cells, andrographolide blocked tumor necrosis factor-alpha-induced phosphorylation of inhibitory kappaB kinase-beta, and downstream inhibitory kappaB alpha degradation, p65 subunit of NF-kappaB phosphorylation, and p65 nuclear translocation and DNA-binding activity. Similarly, andrographolide blocked p65 nuclear translocation and DNA-binding activity in the nuclear extracts from lung tissues of OVA-challenged mice. CONCLUSIONS Our findings implicate a potential therapeutic value of andrographolide in the treatment of asthma and it may act by inhibiting the NF-kappaB pathway at the level of inhibitory kappaB kinase-beta activation.

Anti-Malarial Drug Artesunate Attenuates Experimental Allergic Asthma via Inhibition of the Phosphoinositide 3-Kinase/Akt Pathway

Background Phosphoinositide 3-kinase (PI3K)/Akt pathway is linked to the development of asthma. Anti-malarial drug artesunate is a semi-synthetic derivative of artemisinin, the principal active component of a medicinal plant Artemisia annua, and has been shown to inhibit PI3K/Akt activity. We hypothesized that artesunate may attenuate allergic asthma via inhibition of the PI3K/Akt signaling pathway. Methodology/Principal Findings Female BALB/c mice sensitized and challenged with ovalbumin (OVA) developed airway inflammation. Bronchoalveolar lavage fluid was assessed for total and differential cell counts, and cytokine and chemokine levels. Lung tissues were examined for cell infiltration and mucus hypersecretion, and the expression of inflammatory biomarkers. Airway hyperresponsiveness was monitored by direct airway resistance analysis. Artesunate dose-dependently inhibited OVA-induced increases in total and eosinophil counts, IL-4, IL-5, IL-13 and eotaxin levels in bronchoalveolar lavage fluid. It attenuated OVA-induced lung tissue eosinophilia and airway mucus production, mRNA expression of E-selectin, IL-17, IL-33 and Muc5ac in lung tissues, and airway hyperresponsiveness to methacholine. In normal human bronchial epithelial cells, artesunate blocked epidermal growth factor-induced phosphorylation of Akt and its downstream substrates tuberin, p70S6 kinase and 4E-binding protein 1, and transactivation of NF-κB. Similarly, artesunate blocked the phosphorylation of Akt and its downstream substrates in lung tissues from OVA-challenged mice. Anti-inflammatory effect of artesunate was further confirmed in a house dust mite mouse asthma model. Conclusion/Significance Artesunate ameliorates experimental allergic airway inflammation probably via negative regulation of PI3K/Akt pathway and the downstream NF-κB activity. These findings provide a novel therapeutic value for artesunate in the treatment of allergic asthma.

Andrographolide protects against cigarette smoke-induced oxidative lung injury via augmentation of Nrf2 activity.

Cigarette smoke is a major cause for chronic obstructive pulmonary disease (COPD). Andrographolide is an active biomolecule isolated from the plant Andrographis paniculata. Andrographolide has been shown to activate nuclear factor erythroid‐2‐related factor 2 (Nrf2), a redox‐sensitive antioxidant transcription factor. As Nrf2 activity is reduced in COPD, we hypothesize that andrographolide may have therapeutic value for COPD.

Metabolomics Reveals Altered Metabolic Pathways in Experimental Asthma

Metabolomics refers to the comprehensive analysis of metabolites in biological systems, and has been employed to study patients with asthma based on their urinary metabolite profile. We hypothesize that airway allergic asthma would affect metabolism in the lungs, and could be detected in bronchoalveolar lavage (BAL) fluid (BALF) using a combined liquid chromatography- and gas chromatography-mass spectrometry (MS) platform. The objective of this study was to investigate changes of lung metabolism in allergic asthma by metabolomic analysis of BALF. BALB/c mice were sensitized and challenged with ovalbumin to develop experimental asthma. Dexamethasone was administered to study the effects of corticosteroids on lung metabolism. Metabolites in BALF were measured using liquid chromatography-MS and gas chromatography-MS, and multivariate statistical analysis was performed by orthogonal projections to latent structures discriminant analysis. Metabolomic analysis of BALF from ovalbumin-challenged mice revealed novel changes in metabolic pathways in the lungs as compared with control animals. These metabolite changes suggest alterations of energy metabolism in asthmatic lungs, with increases of lactate, malate, and creatinine and reductions in carbohydrates, such as mannose, galactose, and arabinose. Lipid and sterol metabolism were affected with significant decreases in phosphatidylcholines, diglycerides, triglycerides, cholesterol, cortol, and cholic acid. Dexamethasone treatment effectively reversed many key metabolite changes, but was ineffective in repressing lactate, malate, and creatinine, and induced additional metabolite changes. Metabolomic analysis of BALF offers a promising approach to investigating allergic asthma. Our overall findings revealed considerable pathway changes in lung metabolism in asthmatic lungs, including energy, amino acids, and lipid metabolism.

Anti-malarial drug artesunate ameliorates oxidative lung damage in experimental allergic asthma.

Oxidative stress is a critical pathophysiological factor in the development of allergic airway inflammation, resulting in oxidative damage to lipids, proteins, and DNA. Our recent report revealed potent anti-inflammatory effects of the antimalarial drug artesunate in experimental allergic asthma. The present study investigated potential antioxidative effects of artesunate in a murine model of allergic asthma in comparison with dexamethasone, a potent corticosteroid. Mice were sensitized and challenged with ovalbumin and developed airway inflammation and oxidative lung damage. Artesunate markedly suppressed ovalbumin-induced increases in total cell, eosinophil, and neutrophil counts. In contrast, dexamethasone failed to inhibit neutrophil recruitment. Levels of the oxidative damage markers 8-isoprostane, 8-hydroxy-2-deoxyguanosine, and 3-nitrotyrosine were potently repressed by artesunate. However, dexamethasone showed weaker inhibitory effects on 3-nitrotyrosine production. Ovalbumin-induced increases in the expression of the pro-oxidants iNOS and NADPH oxidase (NOX1, 2, 3, and 4) were significantly abated by artesunate. Gene expression of regulatory subunits of NOX, p22phox and p67phox, was also reduced by artesunate. The expression and activities of the antioxidants superoxide dismutase and catalase were substantially reversed with artesunate in ovalbumin-challenged mice. Artesunate significantly enhanced nuclear levels of nuclear factor erythroid-2-related factor 2 (Nrf2) in lung tissues from ovalbumin-challenged mice and in TNF-α-stimulated human bronchial epithelial cells. Our findings implicate a potential therapeutic value for artesunate in the treatment of asthma via the amelioration of oxidative damage in allergic airways, and it may act by suppressing pro-oxidants and restoring the activities and expression of antioxidants via activation of Nrf2. Artesunate may be a potential novel anti-asthma drug capable of controlling both inflammation and oxidative damage in chronic severe asthma.

Dendritic cell‐derived interferon‐γ‐induced protein mediates tumor necrosis factor‐α stimulation of human lung fibroblasts

Lung fibroblast plays a pivotal role in lung repair and remodeling, and also contributes to lung inflammation. The present study investigated differential protein profiling of normal human lung fibroblasts stimulated with tumor necrosis factor (TNF)‐α. Total proteins from lung fibroblasts were separated by 2‐DE, and differentially expressed proteins were identified by MALDI‐TOF MS. TNF‐α was found for the first time to alter the expression levels of myxovirus resistance protein A, interferon‐stimulated gene 15, plasminogen activator inhibitor‐2, lysyl hydroxylase 2 (isoform a), and prolyl 4‐hydroxylase (α subunit) in human lung fibroblasts. In particular, dendritic cell‐derived interferon‐γ‐induced protein (DCIP) was upregulated by TNF‐α in lung fibroblasts and its biological function is at present unknown. We found that TNF‐α‐induced DCIP expression was dependent on the transcription factor interferon regulatory factor‐1. DCIP‐selective antisense oligodeoxynucleotide inhibited the expression of TNF‐α‐responsive gene targets including vascular cell adhesion molecule‐1, intercellular adhesion molecule‐1, IL‐6, IL‐8, IP‐10, and thymic stromal lymphopoietin. In a lipopolysaccharide‐induced acute lung injury mouse model, DCIP mRNA level was elevated together with that of TNF‐α. We have demonstrated for the first time that DCIP is upregulated by TNF‐α and also mediates TNF‐α stimulation of human lung fibroblasts. Further studies on the role of DCIP in airway inflammation and remodeling are warranted.

Anti-allergic action of anti-malarial drug artesunate in experimental mast cell-mediated anaphylactic models

Allergy is an acquired hypersensitivity reaction of the immune system mediated by cross‐linking of allergen‐specific IgE‐bound high‐affinity IgE receptors, leading to immediate mast cell degranulation. Artesunate is a semi‐synthetic derivative of artemisinin, an active component of the medicinal plant Artemisia annua. Artesunate is a clinically effective anti‐malarial drug and has recently been shown to attenuate allergic asthma in mouse models. This study investigated potential anti‐allergic effects of artesunate in animal models of IgE‐dependent anaphylaxis.

Protective Role of 14-Deoxy-11,12-didehydroandrographolide, a Noncytotoxic Analogue of Andrographolide, in Allergic Airway Inflammation

Our group recently reported novel anti-inflammatory effects of andrographolide (2), a bioactive molecule isolated from Andrographis paniculata, in a mouse asthma model. However, 2 has been shown to possess cytotoxic activity. 14-Deoxy-11,12-didehydroandrographolide (1) is an analogue of 2 that can be isolated from A. paniculata. We hypothesized that 1 retains the anti-inflammatory effects for asthma but is devoid of cytotoxicity. In contrast to 2, 1 did not elicit any cytotoxic activity in A549 and BEAS-2B human lung epithelial cells and rat basophilic leukemia (RBL)-2H3 cells using a MTS assay. Compound 1 dose-dependently inhibited ovalbumin (OVA)-induced increases in total and eosinophil counts, IL-4, IL-5, and IL-13 levels in lavage fluid, and serum OVA-specific IgE level in a mouse asthma model. Compound 1 attenuated OVA-induced airway eosinophilia, mucus production, mast cell degranulation, pro-inflammatory biomarker expression in lung tissues, and airway hyper-responsiveness. This substance also blocked p65 nuclear translocation and DNA-binding activity in the OVA-challenged lung and in TNF-α-stimulated human lung epithelial cells. The present findings reveal for the first time that 1 retains the anti-inflammatory activities of 2 for asthma probably through the inhibition of NF-κB. 14-Deoxy-11,12-didehydroandrographolide (1) may be considered as a safer analogue of 2 for the potential treatment of asthma.

Metabolomics Reveals Inflammatory-Linked Pulmonary Metabolic Alterations in a Murine Model of House Dust Mite-Induced Allergic Asthma

Although the house dust mite (HDM) is a major environmental aeroallergen that promotes the pathogenesis and severity of allergic asthma, it remains elusive if HDM exposures can induce global metabolism aberrations during allergic airway inflammation. Using an integrated gas and liquid chromatography mass spectrometry-based metabolomics and multiplex cytokine profile analysis, metabolic alterations and cytokine changes were investigated in the bronchoalveolar lavage fluid (BALF), serum, and lung tissues in experimental HDM-induced allergic asthma. Allergic pulmonary HDM exposures lead to pronounced eosinophilia, neutrophilia, and increases in inflammatory cytokines. Metabolomics analysis of the BALF, serum, and lung tissues revealed distinctive compartmental metabolic signatures, which included depleted carbohydrates, increased energy metabolites, and consistent losses of sterols and phosphatidylcholines. Pearson correlation analysis uncovered strong associations between specific metabolic alterations and inflammatory cells and cytokines, linking altered pulmonary metabolism to allergic airway inflammation. The clinically prescribed glucocorticoid prednisolone could modulate airway inflammation but was ineffective against the reversal of many HDM-induced metabolic alterations. Collectively, metabolomics reveal comprehensive pulmonary metabolic signatures in HDM-induced allergic asthma, with specific alterations in carbohydrates, lipids, sterols, and energy metabolic pathways. Altered pulmonary metabolism may be a major underlying molecular feature involved during HDM-induced allergic airway inflammation, linked to inflammatory cells and cytokines changes.

Attenuated Bordetella pertussis BPZE1 protects against allergic airway inflammation and contact dermatitis in mouse models

We previously reported that prior nasal administration of highly attenuated Bordetella pertussis BPZE1 provides effective and sustained protection against lethal challenge with influenza A viruses. The protective effect was mediated by suppressing the production of major pro‐inflammatory mediators. To further explore the anti‐inflammatory properties of BPZE1, we investigated the effect of BPZE1 nasal pretreatment on two mouse models of allergic disease, allergic airway inflammation, and contact hypersensitivity (CHS).