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COX-1, and not COX-2 activity, regulates airway function: relevance to aspirin-sensitive asthma.

Harrington LS, Lucas R, McMaster SK, Moreno L, Scadding G, Warner TD, Mitchell JA - FASEB J. (2008)

Bottom Line: Cells cultured from aspirin-sensitive or control human donors contained similar levels of COX-1 and COX-2 immunoreactivity.COX activity in cells from aspirin-sensitive or tolerant patients was inhibited by aspirin, SC560, which blocks COX-1 selectively, but not by rofecoxib, which is a selective inhibitor of COX-2.These observations show that despite the presence of COX-2, COX-1 is functionally predominant in the airways and explains clinical observations relating to drug specificity in patients with aspirin-sensitive asthma.

View Article: PubMed Central - PubMed

Affiliation: Cardiac Medicine, NHLI, Imperial College, Dovehouse St., London SW3 6LY, UK.

ABSTRACT
Cyclooxygenase (COX) -1 and COX-2 are expressed in airway cells, where their activities influence functions such as airway hyperreactivity. Clinical data show that mixed COX-1/COX-2 inhibitors such as aspirin, but not COX-2 selective inhibitors such as rofecoxib, induce bronchoconstriction and asthma in sensitive individuals. This anomaly has not yet been explained. Here, we have used tissue from genetically modified mice lacking functional COX-1 (COX-1(-/-)), as well as airway tissue from "aspirin-sensitive" and control patients to address this issue. Bronchi from wild-type mice contained predominantly COX-1 immunoreactivity and contracted in vitro in response to acetylcholine and U46619. Bronchi from COX-1(-/-) mice were hyperresponsive to bronchoconstrictors. Inhibitors of COX (naproxen, diclofenac, or ibuprofen) increased bronchoconstriction in tissue from wild-type but not from COX-1(-/-) mice. Cells cultured from aspirin-sensitive or control human donors contained similar levels of COX-1 and COX-2 immunoreactivity. COX activity in cells from aspirin-sensitive or tolerant patients was inhibited by aspirin, SC560, which blocks COX-1 selectively, but not by rofecoxib, which is a selective inhibitor of COX-2. These observations show that despite the presence of COX-2, COX-1 is functionally predominant in the airways and explains clinical observations relating to drug specificity in patients with aspirin-sensitive asthma.

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Relative levels of COX-1 and COX-2 expressed in human cells derived from control (no aspirin sensitivity) and aspirin-sensitive donors and cultured under control conditions or in the presence of IL-1β for 24 h. COX-1 and COX-2 immunoreactivity was detected in extracts from control cells and those treated with IL-1β (Α). Positive controls used for this blot were MEG-01 cytosol, which contains only COX-1 (22), and A549 cells treated with IL-1β, which express only COX-2 (23). COX activity in cells measured by release of PGE2 into the medium after incubation with A23187 (10−5 M) for 30 min (B). Data are means ± se; n = 15 experiments (cells from at least 3 different patients; experiments performed in triplicate on at least 5 experimental days); 1-way ANOVA with post hoc test. *P < 0.05.
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Figure 5: Relative levels of COX-1 and COX-2 expressed in human cells derived from control (no aspirin sensitivity) and aspirin-sensitive donors and cultured under control conditions or in the presence of IL-1β for 24 h. COX-1 and COX-2 immunoreactivity was detected in extracts from control cells and those treated with IL-1β (Α). Positive controls used for this blot were MEG-01 cytosol, which contains only COX-1 (22), and A549 cells treated with IL-1β, which express only COX-2 (23). COX activity in cells measured by release of PGE2 into the medium after incubation with A23187 (10−5 M) for 30 min (B). Data are means ± se; n = 15 experiments (cells from at least 3 different patients; experiments performed in triplicate on at least 5 experimental days); 1-way ANOVA with post hoc test. *P < 0.05.

Mentions: Similar to observations made with murine airway tissues, cells cultured from nasal polyps obtained from aspirin-sensitive or aspirin-tolerant patients contained predominantly COX-1 protein. However, although in limited amounts, COX-2 immunoreactivity was detected in cells from both patient groups (Fig. 5A). In contrast to some other types of human cells [e.g., A549 (12, 14), endothelial (15), vascular smooth muscle (16)], the cytokine IL-1β did not induce increased expression of COX-2 in nasal polyp cells (Fig. 5A). Cells cultured from control and aspirin-sensitive individuals released detectable levels of PGE2 over 24 h in culture (Fig. 5B). There was no significant difference in absolute levels of PGE2 released by cells from the two patient groups cultured under control conditions (Fig. 5B). Despite having little or no effect on protein expression, treatment of cells with IL-1β for 24 h increased the release of PGE2. PGE2 release after IL-1β was significantly higher from cells cultured from aspirin-sensitive than from aspirin-tolerant individuals (Fig. 5B).


COX-1, and not COX-2 activity, regulates airway function: relevance to aspirin-sensitive asthma.

Harrington LS, Lucas R, McMaster SK, Moreno L, Scadding G, Warner TD, Mitchell JA - FASEB J. (2008)

Relative levels of COX-1 and COX-2 expressed in human cells derived from control (no aspirin sensitivity) and aspirin-sensitive donors and cultured under control conditions or in the presence of IL-1β for 24 h. COX-1 and COX-2 immunoreactivity was detected in extracts from control cells and those treated with IL-1β (Α). Positive controls used for this blot were MEG-01 cytosol, which contains only COX-1 (22), and A549 cells treated with IL-1β, which express only COX-2 (23). COX activity in cells measured by release of PGE2 into the medium after incubation with A23187 (10−5 M) for 30 min (B). Data are means ± se; n = 15 experiments (cells from at least 3 different patients; experiments performed in triplicate on at least 5 experimental days); 1-way ANOVA with post hoc test. *P < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2691413&req=5

Figure 5: Relative levels of COX-1 and COX-2 expressed in human cells derived from control (no aspirin sensitivity) and aspirin-sensitive donors and cultured under control conditions or in the presence of IL-1β for 24 h. COX-1 and COX-2 immunoreactivity was detected in extracts from control cells and those treated with IL-1β (Α). Positive controls used for this blot were MEG-01 cytosol, which contains only COX-1 (22), and A549 cells treated with IL-1β, which express only COX-2 (23). COX activity in cells measured by release of PGE2 into the medium after incubation with A23187 (10−5 M) for 30 min (B). Data are means ± se; n = 15 experiments (cells from at least 3 different patients; experiments performed in triplicate on at least 5 experimental days); 1-way ANOVA with post hoc test. *P < 0.05.
Mentions: Similar to observations made with murine airway tissues, cells cultured from nasal polyps obtained from aspirin-sensitive or aspirin-tolerant patients contained predominantly COX-1 protein. However, although in limited amounts, COX-2 immunoreactivity was detected in cells from both patient groups (Fig. 5A). In contrast to some other types of human cells [e.g., A549 (12, 14), endothelial (15), vascular smooth muscle (16)], the cytokine IL-1β did not induce increased expression of COX-2 in nasal polyp cells (Fig. 5A). Cells cultured from control and aspirin-sensitive individuals released detectable levels of PGE2 over 24 h in culture (Fig. 5B). There was no significant difference in absolute levels of PGE2 released by cells from the two patient groups cultured under control conditions (Fig. 5B). Despite having little or no effect on protein expression, treatment of cells with IL-1β for 24 h increased the release of PGE2. PGE2 release after IL-1β was significantly higher from cells cultured from aspirin-sensitive than from aspirin-tolerant individuals (Fig. 5B).

Bottom Line: Cells cultured from aspirin-sensitive or control human donors contained similar levels of COX-1 and COX-2 immunoreactivity.COX activity in cells from aspirin-sensitive or tolerant patients was inhibited by aspirin, SC560, which blocks COX-1 selectively, but not by rofecoxib, which is a selective inhibitor of COX-2.These observations show that despite the presence of COX-2, COX-1 is functionally predominant in the airways and explains clinical observations relating to drug specificity in patients with aspirin-sensitive asthma.

View Article: PubMed Central - PubMed

Affiliation: Cardiac Medicine, NHLI, Imperial College, Dovehouse St., London SW3 6LY, UK.

ABSTRACT
Cyclooxygenase (COX) -1 and COX-2 are expressed in airway cells, where their activities influence functions such as airway hyperreactivity. Clinical data show that mixed COX-1/COX-2 inhibitors such as aspirin, but not COX-2 selective inhibitors such as rofecoxib, induce bronchoconstriction and asthma in sensitive individuals. This anomaly has not yet been explained. Here, we have used tissue from genetically modified mice lacking functional COX-1 (COX-1(-/-)), as well as airway tissue from "aspirin-sensitive" and control patients to address this issue. Bronchi from wild-type mice contained predominantly COX-1 immunoreactivity and contracted in vitro in response to acetylcholine and U46619. Bronchi from COX-1(-/-) mice were hyperresponsive to bronchoconstrictors. Inhibitors of COX (naproxen, diclofenac, or ibuprofen) increased bronchoconstriction in tissue from wild-type but not from COX-1(-/-) mice. Cells cultured from aspirin-sensitive or control human donors contained similar levels of COX-1 and COX-2 immunoreactivity. COX activity in cells from aspirin-sensitive or tolerant patients was inhibited by aspirin, SC560, which blocks COX-1 selectively, but not by rofecoxib, which is a selective inhibitor of COX-2. These observations show that despite the presence of COX-2, COX-1 is functionally predominant in the airways and explains clinical observations relating to drug specificity in patients with aspirin-sensitive asthma.

Show MeSH
Related in: MedlinePlus