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An intranasal selective antisense oligonucleotide impairs lung cyclooxygenase-2 production and improves inflammation, but worsens airway function, in house dust mite sensitive mice.

Torres R, Herrerias A, Serra-Pagès M, Roca-Ferrer J, Pujols L, Marco A, Picado C, de Mora F - Respir. Res. (2008)

Bottom Line: Finally, mRNA levels of hPGD synthase remained unchanged.Intranasal antisense therapy against COX-2 in vivo mimicked the reported impairment of COX-2 regulation in the airway cells of asthmatic patients.This strategy revealed an unexpected novel dual effect: inflammation was improved but AHR worsened.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pneumology and Respiratory Allergy, Hospital Clínic, IDIBAPS, Universitat de Barcelona, Barcelona, Spain. rosa.torres@uab.cat

ABSTRACT

Background: Despite its reported pro-inflammatory activity, cyclooxygenase (COX)-2 has been proposed to play a protective role in asthma. Accordingly, COX-2 might be down-regulated in the airway cells of asthmatics. This, together with results of experiments to assess the impact of COX-2 blockade in ovalbumin (OVA)-sensitized mice in vivo, led us to propose a novel experimental approach using house dust mite (HDM)-sensitized mice in which we mimicked altered regulation of COX-2.

Methods: Allergic inflammation was induced in BALBc mice by intranasal exposure to HDM for 10 consecutive days. This model reproduces spontaneous exposure to aeroallergens by asthmatic patients. In order to impair, but not fully block, COX-2 production in the airways, some of the animals received an intranasal antisense oligonucleotide. Lung COX-2 expression and activity were measured along with bronchovascular inflammation, airway reactivity, and prostaglandin production.

Results: We observed impaired COX-2 mRNA and protein expression in the lung tissue of selective oligonucleotide-treated sensitized mice. This was accompanied by diminished production of mPGE synthase and PGE2 in the airways. In sensitized mice, the oligonucleotide induced increased airway hyperreactivity (AHR) to methacholine, but a substantially reduced bronchovascular inflammation. Finally, mRNA levels of hPGD synthase remained unchanged.

Conclusion: Intranasal antisense therapy against COX-2 in vivo mimicked the reported impairment of COX-2 regulation in the airway cells of asthmatic patients. This strategy revealed an unexpected novel dual effect: inflammation was improved but AHR worsened. This approach will provide insights into the differential regulation of inflammation and lung function in asthma, and will help identify pharmacological targets within the COX-2/PG system.

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Related in: MedlinePlus

Photomicrographs of COX-2 immunolabeling in lung samples from HDM-sensitized mice following different treatments. Pictures a, b, and c show representative images of the COX-2 immunostaining pattern in the airways. Since the COX-2 distribution was almost the same in all 4 experimental groups, only representative images of one of them are included. 3 (a) shows a general view of COX-2 distribution in the airways, where labeling is detected in the bronchiolar epithelium but not in the principal airway. 3 (b) shows a single bronchiole (magnified view of the area outlined in [a]), and 3 (c) shows stained alveolar macrophages. Pictures d, e, and f reflect the consistent changes in the COX-2 antigen signal intensity under different experimental conditions. 3 (d) shows a single bronchiole from a non-sensitized mouse, 3 (e) A single bronchiole from a sensitized mouse treated with control mismatched oligonucleotides (MM), and 3 (f) COX-2 protein expression in the airways after treatment with the COX-2 antisense oligonucleotide (ASO). Similar staining intensity was seen in untreated sensitized mice, in which cells were heterogeneously labeled and peribronchial and perivascular inflammation was observed, but the immunostaining signal diminished clearly and consistently in the treatment group.
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Figure 3: Photomicrographs of COX-2 immunolabeling in lung samples from HDM-sensitized mice following different treatments. Pictures a, b, and c show representative images of the COX-2 immunostaining pattern in the airways. Since the COX-2 distribution was almost the same in all 4 experimental groups, only representative images of one of them are included. 3 (a) shows a general view of COX-2 distribution in the airways, where labeling is detected in the bronchiolar epithelium but not in the principal airway. 3 (b) shows a single bronchiole (magnified view of the area outlined in [a]), and 3 (c) shows stained alveolar macrophages. Pictures d, e, and f reflect the consistent changes in the COX-2 antigen signal intensity under different experimental conditions. 3 (d) shows a single bronchiole from a non-sensitized mouse, 3 (e) A single bronchiole from a sensitized mouse treated with control mismatched oligonucleotides (MM), and 3 (f) COX-2 protein expression in the airways after treatment with the COX-2 antisense oligonucleotide (ASO). Similar staining intensity was seen in untreated sensitized mice, in which cells were heterogeneously labeled and peribronchial and perivascular inflammation was observed, but the immunostaining signal diminished clearly and consistently in the treatment group.

Mentions: The concentration of COX-2 in lung protein extracts from some of the mice was measured by ELISA. A significant 45% reduction in COX-2 protein concentrations was observed in the lungs of COX-2 antisense-treated sensitized mice compared with non-treated sensitized mice (Figure 2b). Analysis of COX-2 expression in the lung by immunohistochemistry showed the same results for untreated HDM-sensitized mice and mismatched control oligonucleotide-treated sensitized mice (Figure 3e), that is, they consistently had a visibly increased number of positive cells and a stronger staining intensity than selective COX-2 oligonucleotide-treated mice (Figure 3f).


An intranasal selective antisense oligonucleotide impairs lung cyclooxygenase-2 production and improves inflammation, but worsens airway function, in house dust mite sensitive mice.

Torres R, Herrerias A, Serra-Pagès M, Roca-Ferrer J, Pujols L, Marco A, Picado C, de Mora F - Respir. Res. (2008)

Photomicrographs of COX-2 immunolabeling in lung samples from HDM-sensitized mice following different treatments. Pictures a, b, and c show representative images of the COX-2 immunostaining pattern in the airways. Since the COX-2 distribution was almost the same in all 4 experimental groups, only representative images of one of them are included. 3 (a) shows a general view of COX-2 distribution in the airways, where labeling is detected in the bronchiolar epithelium but not in the principal airway. 3 (b) shows a single bronchiole (magnified view of the area outlined in [a]), and 3 (c) shows stained alveolar macrophages. Pictures d, e, and f reflect the consistent changes in the COX-2 antigen signal intensity under different experimental conditions. 3 (d) shows a single bronchiole from a non-sensitized mouse, 3 (e) A single bronchiole from a sensitized mouse treated with control mismatched oligonucleotides (MM), and 3 (f) COX-2 protein expression in the airways after treatment with the COX-2 antisense oligonucleotide (ASO). Similar staining intensity was seen in untreated sensitized mice, in which cells were heterogeneously labeled and peribronchial and perivascular inflammation was observed, but the immunostaining signal diminished clearly and consistently in the treatment group.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2600823&req=5

Figure 3: Photomicrographs of COX-2 immunolabeling in lung samples from HDM-sensitized mice following different treatments. Pictures a, b, and c show representative images of the COX-2 immunostaining pattern in the airways. Since the COX-2 distribution was almost the same in all 4 experimental groups, only representative images of one of them are included. 3 (a) shows a general view of COX-2 distribution in the airways, where labeling is detected in the bronchiolar epithelium but not in the principal airway. 3 (b) shows a single bronchiole (magnified view of the area outlined in [a]), and 3 (c) shows stained alveolar macrophages. Pictures d, e, and f reflect the consistent changes in the COX-2 antigen signal intensity under different experimental conditions. 3 (d) shows a single bronchiole from a non-sensitized mouse, 3 (e) A single bronchiole from a sensitized mouse treated with control mismatched oligonucleotides (MM), and 3 (f) COX-2 protein expression in the airways after treatment with the COX-2 antisense oligonucleotide (ASO). Similar staining intensity was seen in untreated sensitized mice, in which cells were heterogeneously labeled and peribronchial and perivascular inflammation was observed, but the immunostaining signal diminished clearly and consistently in the treatment group.
Mentions: The concentration of COX-2 in lung protein extracts from some of the mice was measured by ELISA. A significant 45% reduction in COX-2 protein concentrations was observed in the lungs of COX-2 antisense-treated sensitized mice compared with non-treated sensitized mice (Figure 2b). Analysis of COX-2 expression in the lung by immunohistochemistry showed the same results for untreated HDM-sensitized mice and mismatched control oligonucleotide-treated sensitized mice (Figure 3e), that is, they consistently had a visibly increased number of positive cells and a stronger staining intensity than selective COX-2 oligonucleotide-treated mice (Figure 3f).

Bottom Line: Finally, mRNA levels of hPGD synthase remained unchanged.Intranasal antisense therapy against COX-2 in vivo mimicked the reported impairment of COX-2 regulation in the airway cells of asthmatic patients.This strategy revealed an unexpected novel dual effect: inflammation was improved but AHR worsened.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pneumology and Respiratory Allergy, Hospital Clínic, IDIBAPS, Universitat de Barcelona, Barcelona, Spain. rosa.torres@uab.cat

ABSTRACT

Background: Despite its reported pro-inflammatory activity, cyclooxygenase (COX)-2 has been proposed to play a protective role in asthma. Accordingly, COX-2 might be down-regulated in the airway cells of asthmatics. This, together with results of experiments to assess the impact of COX-2 blockade in ovalbumin (OVA)-sensitized mice in vivo, led us to propose a novel experimental approach using house dust mite (HDM)-sensitized mice in which we mimicked altered regulation of COX-2.

Methods: Allergic inflammation was induced in BALBc mice by intranasal exposure to HDM for 10 consecutive days. This model reproduces spontaneous exposure to aeroallergens by asthmatic patients. In order to impair, but not fully block, COX-2 production in the airways, some of the animals received an intranasal antisense oligonucleotide. Lung COX-2 expression and activity were measured along with bronchovascular inflammation, airway reactivity, and prostaglandin production.

Results: We observed impaired COX-2 mRNA and protein expression in the lung tissue of selective oligonucleotide-treated sensitized mice. This was accompanied by diminished production of mPGE synthase and PGE2 in the airways. In sensitized mice, the oligonucleotide induced increased airway hyperreactivity (AHR) to methacholine, but a substantially reduced bronchovascular inflammation. Finally, mRNA levels of hPGD synthase remained unchanged.

Conclusion: Intranasal antisense therapy against COX-2 in vivo mimicked the reported impairment of COX-2 regulation in the airway cells of asthmatic patients. This strategy revealed an unexpected novel dual effect: inflammation was improved but AHR worsened. This approach will provide insights into the differential regulation of inflammation and lung function in asthma, and will help identify pharmacological targets within the COX-2/PG system.

Show MeSH
Related in: MedlinePlus