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Inhibition of aldose reductase prevents experimental allergic airway inflammation in mice.

Yadav UC, Ramana KV, Aguilera-Aguirre L, Boldogh I, Boulares HA, Srivastava SK - PLoS ONE (2009)

Bottom Line: Our results indicate that inhibition of AR prevents RWE -induced apoptotic cell death as measured by annexin-v staining, increase in the activation of NF-kappaB and expression of inflammatory markers such as inducible nitric oxide synthase (iNOS), cycloxygenase (COX)-2, Prostaglandin (PG) E(2), IL-6 and IL-8.Our results indicate that inhibition of AR prevents airway inflammation and production of inflammatory cytokines, accumulation of eosinophils in airways and sub-epithelial regions, mucin production in the bronchoalveolar lavage fluid and airway hyperresponsiveness in mice.These results suggest that airway inflammation due to allergic response to RWE, which subsequently activates oxidative stress-induced expression of inflammatory cytokines via NF-kappaB-dependent mechanism, could be prevented by AR inhibitors.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Immunology, University of Texas Medical Branch, Galveston, Texas, United States.

ABSTRACT

Background: The bronchial asthma, a clinical complication of persistent inflammation of the airway and subsequent airway hyper-responsiveness, is a leading cause of morbidity and mortality in critically ill patients. Several studies have shown that oxidative stress plays a key role in initiation as well as amplification of inflammation in airways. However, still there are no good anti-oxidant strategies available for therapeutic intervention in asthma pathogenesis. Most recent studies suggest that polyol pathway enzyme, aldose reductase (AR), contributes to the pathogenesis of oxidative stress-induced inflammation by affecting the NF-kappaB-dependent expression of cytokines and chemokines and therefore inhibitors of AR could be anti-inflammatory. Since inhibitors of AR have already gone through phase-III clinical studies for diabetic complications and found to be safe, our hypothesis is that AR inhibitors could be novel therapeutic drugs for the prevention and treatment of asthma. Hence, we investigated the efficacy of AR inhibition in the prevention of allergic responses to a common natural airborne allergen, ragweed pollen that leads to airway inflammation and hyper-responsiveness in a murine model of asthma.

Methods and findings: Primary Human Small Airway Epithelial Cells (SAEC) were used to investigate the in vitro effects of AR inhibition on ragweed pollen extract (RWE)-induced cytotoxic and inflammatory signals. Our results indicate that inhibition of AR prevents RWE -induced apoptotic cell death as measured by annexin-v staining, increase in the activation of NF-kappaB and expression of inflammatory markers such as inducible nitric oxide synthase (iNOS), cycloxygenase (COX)-2, Prostaglandin (PG) E(2), IL-6 and IL-8. Further, BALB/c mice were sensitized with endotoxin-free RWE in the absence and presence of AR inhibitor and followed by evaluation of perivascular and peribronchial inflammation, mucin production, eosinophils infiltration and airway hyperresponsiveness. Our results indicate that inhibition of AR prevents airway inflammation and production of inflammatory cytokines, accumulation of eosinophils in airways and sub-epithelial regions, mucin production in the bronchoalveolar lavage fluid and airway hyperresponsiveness in mice.

Conclusions: These results suggest that airway inflammation due to allergic response to RWE, which subsequently activates oxidative stress-induced expression of inflammatory cytokines via NF-kappaB-dependent mechanism, could be prevented by AR inhibitors. Therefore, inhibition of AR could have clinical implications, especially for the treatment of airway inflammation, a major cause of asthma pathogenesis.

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Inhibition of AR prevents RWE-induced ROS generation in SAEC.Approximately 1×105 cells were seeded on 2-chambered slides and starved in serum-free basal medium with or without AR inhibitors, sorbinil or zopolrestat, for 24 h. The cells were treated with RWE (150 µg/ml) for 16 h. The SAEC were washed with cold PBS (pH 7.2) and stained with ROS-sensitive dye, dihydroethidium (DHE) for 15 min at 37°C. The cells were washed again and mounted with floursave (with diamidino-2-phenylindole (DAPI)) mounting medium. Photomicrographs were acquired by a fluorescence microscope (Nikon). A representative picture is given (n = 4); Magnification 200×. ARI, aldose reducatse inhibitor.
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pone-0006535-g002: Inhibition of AR prevents RWE-induced ROS generation in SAEC.Approximately 1×105 cells were seeded on 2-chambered slides and starved in serum-free basal medium with or without AR inhibitors, sorbinil or zopolrestat, for 24 h. The cells were treated with RWE (150 µg/ml) for 16 h. The SAEC were washed with cold PBS (pH 7.2) and stained with ROS-sensitive dye, dihydroethidium (DHE) for 15 min at 37°C. The cells were washed again and mounted with floursave (with diamidino-2-phenylindole (DAPI)) mounting medium. Photomicrographs were acquired by a fluorescence microscope (Nikon). A representative picture is given (n = 4); Magnification 200×. ARI, aldose reducatse inhibitor.

Mentions: It has been reported that addition of RWE to cultured epithelial cells or airways increases oxidative stress levels within minutes after exposure [21], [25]. To examine the nature of the RWE-induced decrease in SAEC viability, we measured the level of ROS in RWE-induced SAEC and whether AR inhibitors could prevent it. As shown in Fig. 2, RWE (150 µg/mL) caused increase in cellular ROS levels as evident by increased fluorescence by ROS sensitive dihydroethidium (DHE). Pre-incubation of SAEC with two different AR inhibitors, sorbinil or zopolrestat, prevented these changes (Fig. 2). Under the similar conditions, AR inhibition alone caused no significant change in the ROS levels in SAEC. These results suggest that inhibition of AR increased antioxidant potential of cells and prevented RWE-induced increase in ROS and resultant cell death.


Inhibition of aldose reductase prevents experimental allergic airway inflammation in mice.

Yadav UC, Ramana KV, Aguilera-Aguirre L, Boldogh I, Boulares HA, Srivastava SK - PLoS ONE (2009)

Inhibition of AR prevents RWE-induced ROS generation in SAEC.Approximately 1×105 cells were seeded on 2-chambered slides and starved in serum-free basal medium with or without AR inhibitors, sorbinil or zopolrestat, for 24 h. The cells were treated with RWE (150 µg/ml) for 16 h. The SAEC were washed with cold PBS (pH 7.2) and stained with ROS-sensitive dye, dihydroethidium (DHE) for 15 min at 37°C. The cells were washed again and mounted with floursave (with diamidino-2-phenylindole (DAPI)) mounting medium. Photomicrographs were acquired by a fluorescence microscope (Nikon). A representative picture is given (n = 4); Magnification 200×. ARI, aldose reducatse inhibitor.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2717330&req=5

pone-0006535-g002: Inhibition of AR prevents RWE-induced ROS generation in SAEC.Approximately 1×105 cells were seeded on 2-chambered slides and starved in serum-free basal medium with or without AR inhibitors, sorbinil or zopolrestat, for 24 h. The cells were treated with RWE (150 µg/ml) for 16 h. The SAEC were washed with cold PBS (pH 7.2) and stained with ROS-sensitive dye, dihydroethidium (DHE) for 15 min at 37°C. The cells were washed again and mounted with floursave (with diamidino-2-phenylindole (DAPI)) mounting medium. Photomicrographs were acquired by a fluorescence microscope (Nikon). A representative picture is given (n = 4); Magnification 200×. ARI, aldose reducatse inhibitor.
Mentions: It has been reported that addition of RWE to cultured epithelial cells or airways increases oxidative stress levels within minutes after exposure [21], [25]. To examine the nature of the RWE-induced decrease in SAEC viability, we measured the level of ROS in RWE-induced SAEC and whether AR inhibitors could prevent it. As shown in Fig. 2, RWE (150 µg/mL) caused increase in cellular ROS levels as evident by increased fluorescence by ROS sensitive dihydroethidium (DHE). Pre-incubation of SAEC with two different AR inhibitors, sorbinil or zopolrestat, prevented these changes (Fig. 2). Under the similar conditions, AR inhibition alone caused no significant change in the ROS levels in SAEC. These results suggest that inhibition of AR increased antioxidant potential of cells and prevented RWE-induced increase in ROS and resultant cell death.

Bottom Line: Our results indicate that inhibition of AR prevents RWE -induced apoptotic cell death as measured by annexin-v staining, increase in the activation of NF-kappaB and expression of inflammatory markers such as inducible nitric oxide synthase (iNOS), cycloxygenase (COX)-2, Prostaglandin (PG) E(2), IL-6 and IL-8.Our results indicate that inhibition of AR prevents airway inflammation and production of inflammatory cytokines, accumulation of eosinophils in airways and sub-epithelial regions, mucin production in the bronchoalveolar lavage fluid and airway hyperresponsiveness in mice.These results suggest that airway inflammation due to allergic response to RWE, which subsequently activates oxidative stress-induced expression of inflammatory cytokines via NF-kappaB-dependent mechanism, could be prevented by AR inhibitors.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Immunology, University of Texas Medical Branch, Galveston, Texas, United States.

ABSTRACT

Background: The bronchial asthma, a clinical complication of persistent inflammation of the airway and subsequent airway hyper-responsiveness, is a leading cause of morbidity and mortality in critically ill patients. Several studies have shown that oxidative stress plays a key role in initiation as well as amplification of inflammation in airways. However, still there are no good anti-oxidant strategies available for therapeutic intervention in asthma pathogenesis. Most recent studies suggest that polyol pathway enzyme, aldose reductase (AR), contributes to the pathogenesis of oxidative stress-induced inflammation by affecting the NF-kappaB-dependent expression of cytokines and chemokines and therefore inhibitors of AR could be anti-inflammatory. Since inhibitors of AR have already gone through phase-III clinical studies for diabetic complications and found to be safe, our hypothesis is that AR inhibitors could be novel therapeutic drugs for the prevention and treatment of asthma. Hence, we investigated the efficacy of AR inhibition in the prevention of allergic responses to a common natural airborne allergen, ragweed pollen that leads to airway inflammation and hyper-responsiveness in a murine model of asthma.

Methods and findings: Primary Human Small Airway Epithelial Cells (SAEC) were used to investigate the in vitro effects of AR inhibition on ragweed pollen extract (RWE)-induced cytotoxic and inflammatory signals. Our results indicate that inhibition of AR prevents RWE -induced apoptotic cell death as measured by annexin-v staining, increase in the activation of NF-kappaB and expression of inflammatory markers such as inducible nitric oxide synthase (iNOS), cycloxygenase (COX)-2, Prostaglandin (PG) E(2), IL-6 and IL-8. Further, BALB/c mice were sensitized with endotoxin-free RWE in the absence and presence of AR inhibitor and followed by evaluation of perivascular and peribronchial inflammation, mucin production, eosinophils infiltration and airway hyperresponsiveness. Our results indicate that inhibition of AR prevents airway inflammation and production of inflammatory cytokines, accumulation of eosinophils in airways and sub-epithelial regions, mucin production in the bronchoalveolar lavage fluid and airway hyperresponsiveness in mice.

Conclusions: These results suggest that airway inflammation due to allergic response to RWE, which subsequently activates oxidative stress-induced expression of inflammatory cytokines via NF-kappaB-dependent mechanism, could be prevented by AR inhibitors. Therefore, inhibition of AR could have clinical implications, especially for the treatment of airway inflammation, a major cause of asthma pathogenesis.

Show MeSH
Related in: MedlinePlus