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Heme oxygenase-1 protects corexit 9500A-induced respiratory epithelial injury across species.

Li FJ, Duggal RN, Oliva OM, Karki S, Surolia R, Wang Z, Watson RD, Thannickal VJ, Powell M, Watts S, Kulkarni T, Batra H, Bolisetty S, Agarwal A, Antony VB - PLoS ONE (2015)

Bottom Line: CE induced the expression of HO-1 as well as C-reactive protein (CRP) and NADPH oxidase 4 (NOX4), which are associated with ROS production.Treatment with carbon monoxide releasing molecule-2 (CORM-2) significantly inhibited CE-induced ROS production, while the addition of HO-1 inhibitor, significantly increased CE-induced ROS production and apoptosis, suggesting a protective role of HO-1 or its reaction product, CO, in CE-induced apoptosis.Using HO-1 knockout mice, we further demonstrated that HO-1 protected against CE-induced inflammation and cellular apoptosis and corrected CE-mediated inhibition of E-cadherin and FAK.

View Article: PubMed Central - PubMed

Affiliation: Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America.

ABSTRACT
The effects of Corexit 9500A (CE) on respiratory epithelial surfaces of terrestrial mammals and marine animals are largely unknown. This study investigated the role of CE-induced heme oxygenase-1 (HO-1), a cytoprotective enzyme with anti-apoptotic and antioxidant activity, in human bronchial airway epithelium and the gills of exposed aquatic animals. We evaluated CE-mediated alterations in human airway epithelial cells, mice lungs and gills from zebrafish and blue crabs. Our results demonstrated that CE induced an increase in gill epithelial edema and human epithelial monolayer permeability, suggesting an acute injury caused by CE exposure. CE induced the expression of HO-1 as well as C-reactive protein (CRP) and NADPH oxidase 4 (NOX4), which are associated with ROS production. Importantly, CE induced caspase-3 activation and subsequent apoptosis of epithelial cells. The expression of the intercellular junctional proteins, such as tight junction proteins occludin, zonula occludens (ZO-1), ZO-2 and adherens junctional proteins E-cadherin and Focal Adhesion Kinase (FAK), were remarkably inhibited by CE, suggesting that these proteins are involved in CE-induced increased permeability and subsequent apoptosis. The cytoskeletal protein F-actin was also disrupted by CE. Treatment with carbon monoxide releasing molecule-2 (CORM-2) significantly inhibited CE-induced ROS production, while the addition of HO-1 inhibitor, significantly increased CE-induced ROS production and apoptosis, suggesting a protective role of HO-1 or its reaction product, CO, in CE-induced apoptosis. Using HO-1 knockout mice, we further demonstrated that HO-1 protected against CE-induced inflammation and cellular apoptosis and corrected CE-mediated inhibition of E-cadherin and FAK. These observations suggest that CE activates CRP and NOX4-mediated ROS production, alters permeability by inhibition of junctional proteins, and leads to caspase-3 dependent apoptosis of epithelial cells, while HO-1 and its reaction products protect against oxidative stress and apoptosis.

No MeSH data available.


Related in: MedlinePlus

CE-induced apoptosis is caspase-3 dependent.(A) CE instigates apoptosis in BEAS-2B cells. Cells were pretreated with or without 10 μM ZnPP for overnight. Following exposure of BEAS-2B cells to 0 ppm, 150 ppm or 300 ppm (data not shown) of CE for 1 or 4 hours, flow cytometry dot plots for the simultaneous binding of Annexin V-FITC and PI uptake were shown. Numbers in the gates represent percentages of Dead (D) cells, as well as early (E), and late (L) apoptotic events. The data are representative of three independent experiments. Percentages of dead cells (PI+Annexin V-) and apoptotic cells (Annexin V+) were quantified and data are shown as a mean ± SD. * p < 0.05, ** p < 0.01 vs no CE control in the absence of ZnPP; # p < 0.05, ## p < 0.01 vs no CE treatment in the presence of ZnPP; & p < 0.05, && p < 0.01 vs with CE treatment in the absence of ZnPP by a one-way ANOVA with HSD test. (B) Representative western blots and associated quantification for active caspase-3, normalized by β-actin content. BEAS-2B cells were exposed to 0 to 150 ppm of CE for 4 hours. Antibodies specific cleaved caspase-3 was used and β-actin was used as a loading control. The representative blots from three independent experiments are shown. The densities of protein bands were determined by densitometry and the data represent a one-fold increase from the control density. (C) Caspase-3 activity was measured using a DEVD-pNA calorimetric assay. After treatment with different concentration of CE for 4 hours, cells were lysed and 100 μg of protein was incubated with 200 μM DEVD-pNA for 6 hours at 37°C. Absorbance measurements were taken at a wavelength of 405 nm and the fold induction of caspase-3 activity relative to the control was shown. * p < 0.05 and ** p < 0.01 vs control by a one-way ANOVA with HSD test. (D) Mice tracheal explants were isolated and IHC analysis was performed after exposure 0 ppm or 150 ppm CE for 2 hours. (E) Blue crabs were exposed to 0 ppm or 150 ppm CE for 19 hours. Gill tissues were harvested for IHC analysis using a cleaved caspase-3 polyclonal antibody (1:800 dilution) followed by treatment with biotinylated goat anti-rabbit antibody and streptavidin–alkaline phosphatase (AP), which produced a red coloration for cleaved caspase-3 positive areas.
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pone.0122275.g002: CE-induced apoptosis is caspase-3 dependent.(A) CE instigates apoptosis in BEAS-2B cells. Cells were pretreated with or without 10 μM ZnPP for overnight. Following exposure of BEAS-2B cells to 0 ppm, 150 ppm or 300 ppm (data not shown) of CE for 1 or 4 hours, flow cytometry dot plots for the simultaneous binding of Annexin V-FITC and PI uptake were shown. Numbers in the gates represent percentages of Dead (D) cells, as well as early (E), and late (L) apoptotic events. The data are representative of three independent experiments. Percentages of dead cells (PI+Annexin V-) and apoptotic cells (Annexin V+) were quantified and data are shown as a mean ± SD. * p < 0.05, ** p < 0.01 vs no CE control in the absence of ZnPP; # p < 0.05, ## p < 0.01 vs no CE treatment in the presence of ZnPP; & p < 0.05, && p < 0.01 vs with CE treatment in the absence of ZnPP by a one-way ANOVA with HSD test. (B) Representative western blots and associated quantification for active caspase-3, normalized by β-actin content. BEAS-2B cells were exposed to 0 to 150 ppm of CE for 4 hours. Antibodies specific cleaved caspase-3 was used and β-actin was used as a loading control. The representative blots from three independent experiments are shown. The densities of protein bands were determined by densitometry and the data represent a one-fold increase from the control density. (C) Caspase-3 activity was measured using a DEVD-pNA calorimetric assay. After treatment with different concentration of CE for 4 hours, cells were lysed and 100 μg of protein was incubated with 200 μM DEVD-pNA for 6 hours at 37°C. Absorbance measurements were taken at a wavelength of 405 nm and the fold induction of caspase-3 activity relative to the control was shown. * p < 0.05 and ** p < 0.01 vs control by a one-way ANOVA with HSD test. (D) Mice tracheal explants were isolated and IHC analysis was performed after exposure 0 ppm or 150 ppm CE for 2 hours. (E) Blue crabs were exposed to 0 ppm or 150 ppm CE for 19 hours. Gill tissues were harvested for IHC analysis using a cleaved caspase-3 polyclonal antibody (1:800 dilution) followed by treatment with biotinylated goat anti-rabbit antibody and streptavidin–alkaline phosphatase (AP), which produced a red coloration for cleaved caspase-3 positive areas.

Mentions: The extent of the apoptotic response to CE exposure was evaluated using FITC-Annexin V and PI staining followed by flow cytometry (Fig. 2A). Flow cytometry analysis demonstrated that CE treatment increased cellular apoptosis. Compared to control, the percentage of apoptotic cells (Annexin V+ cells) increased from 0.4% to 2.1% after 1 hour and from 4.1% to 8.3% after 4 hours. Cell exposure to CE also showed a significant increase in dead cells (PI+ Annexin V- cell, increased from 1.9% to 4.5% after 4 hours). These findings indicate that CE exposure induces epithelial cell apoptosis, which is exposure time and dose dependent.


Heme oxygenase-1 protects corexit 9500A-induced respiratory epithelial injury across species.

Li FJ, Duggal RN, Oliva OM, Karki S, Surolia R, Wang Z, Watson RD, Thannickal VJ, Powell M, Watts S, Kulkarni T, Batra H, Bolisetty S, Agarwal A, Antony VB - PLoS ONE (2015)

CE-induced apoptosis is caspase-3 dependent.(A) CE instigates apoptosis in BEAS-2B cells. Cells were pretreated with or without 10 μM ZnPP for overnight. Following exposure of BEAS-2B cells to 0 ppm, 150 ppm or 300 ppm (data not shown) of CE for 1 or 4 hours, flow cytometry dot plots for the simultaneous binding of Annexin V-FITC and PI uptake were shown. Numbers in the gates represent percentages of Dead (D) cells, as well as early (E), and late (L) apoptotic events. The data are representative of three independent experiments. Percentages of dead cells (PI+Annexin V-) and apoptotic cells (Annexin V+) were quantified and data are shown as a mean ± SD. * p < 0.05, ** p < 0.01 vs no CE control in the absence of ZnPP; # p < 0.05, ## p < 0.01 vs no CE treatment in the presence of ZnPP; & p < 0.05, && p < 0.01 vs with CE treatment in the absence of ZnPP by a one-way ANOVA with HSD test. (B) Representative western blots and associated quantification for active caspase-3, normalized by β-actin content. BEAS-2B cells were exposed to 0 to 150 ppm of CE for 4 hours. Antibodies specific cleaved caspase-3 was used and β-actin was used as a loading control. The representative blots from three independent experiments are shown. The densities of protein bands were determined by densitometry and the data represent a one-fold increase from the control density. (C) Caspase-3 activity was measured using a DEVD-pNA calorimetric assay. After treatment with different concentration of CE for 4 hours, cells were lysed and 100 μg of protein was incubated with 200 μM DEVD-pNA for 6 hours at 37°C. Absorbance measurements were taken at a wavelength of 405 nm and the fold induction of caspase-3 activity relative to the control was shown. * p < 0.05 and ** p < 0.01 vs control by a one-way ANOVA with HSD test. (D) Mice tracheal explants were isolated and IHC analysis was performed after exposure 0 ppm or 150 ppm CE for 2 hours. (E) Blue crabs were exposed to 0 ppm or 150 ppm CE for 19 hours. Gill tissues were harvested for IHC analysis using a cleaved caspase-3 polyclonal antibody (1:800 dilution) followed by treatment with biotinylated goat anti-rabbit antibody and streptavidin–alkaline phosphatase (AP), which produced a red coloration for cleaved caspase-3 positive areas.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4383564&req=5

pone.0122275.g002: CE-induced apoptosis is caspase-3 dependent.(A) CE instigates apoptosis in BEAS-2B cells. Cells were pretreated with or without 10 μM ZnPP for overnight. Following exposure of BEAS-2B cells to 0 ppm, 150 ppm or 300 ppm (data not shown) of CE for 1 or 4 hours, flow cytometry dot plots for the simultaneous binding of Annexin V-FITC and PI uptake were shown. Numbers in the gates represent percentages of Dead (D) cells, as well as early (E), and late (L) apoptotic events. The data are representative of three independent experiments. Percentages of dead cells (PI+Annexin V-) and apoptotic cells (Annexin V+) were quantified and data are shown as a mean ± SD. * p < 0.05, ** p < 0.01 vs no CE control in the absence of ZnPP; # p < 0.05, ## p < 0.01 vs no CE treatment in the presence of ZnPP; & p < 0.05, && p < 0.01 vs with CE treatment in the absence of ZnPP by a one-way ANOVA with HSD test. (B) Representative western blots and associated quantification for active caspase-3, normalized by β-actin content. BEAS-2B cells were exposed to 0 to 150 ppm of CE for 4 hours. Antibodies specific cleaved caspase-3 was used and β-actin was used as a loading control. The representative blots from three independent experiments are shown. The densities of protein bands were determined by densitometry and the data represent a one-fold increase from the control density. (C) Caspase-3 activity was measured using a DEVD-pNA calorimetric assay. After treatment with different concentration of CE for 4 hours, cells were lysed and 100 μg of protein was incubated with 200 μM DEVD-pNA for 6 hours at 37°C. Absorbance measurements were taken at a wavelength of 405 nm and the fold induction of caspase-3 activity relative to the control was shown. * p < 0.05 and ** p < 0.01 vs control by a one-way ANOVA with HSD test. (D) Mice tracheal explants were isolated and IHC analysis was performed after exposure 0 ppm or 150 ppm CE for 2 hours. (E) Blue crabs were exposed to 0 ppm or 150 ppm CE for 19 hours. Gill tissues were harvested for IHC analysis using a cleaved caspase-3 polyclonal antibody (1:800 dilution) followed by treatment with biotinylated goat anti-rabbit antibody and streptavidin–alkaline phosphatase (AP), which produced a red coloration for cleaved caspase-3 positive areas.
Mentions: The extent of the apoptotic response to CE exposure was evaluated using FITC-Annexin V and PI staining followed by flow cytometry (Fig. 2A). Flow cytometry analysis demonstrated that CE treatment increased cellular apoptosis. Compared to control, the percentage of apoptotic cells (Annexin V+ cells) increased from 0.4% to 2.1% after 1 hour and from 4.1% to 8.3% after 4 hours. Cell exposure to CE also showed a significant increase in dead cells (PI+ Annexin V- cell, increased from 1.9% to 4.5% after 4 hours). These findings indicate that CE exposure induces epithelial cell apoptosis, which is exposure time and dose dependent.

Bottom Line: CE induced the expression of HO-1 as well as C-reactive protein (CRP) and NADPH oxidase 4 (NOX4), which are associated with ROS production.Treatment with carbon monoxide releasing molecule-2 (CORM-2) significantly inhibited CE-induced ROS production, while the addition of HO-1 inhibitor, significantly increased CE-induced ROS production and apoptosis, suggesting a protective role of HO-1 or its reaction product, CO, in CE-induced apoptosis.Using HO-1 knockout mice, we further demonstrated that HO-1 protected against CE-induced inflammation and cellular apoptosis and corrected CE-mediated inhibition of E-cadherin and FAK.

View Article: PubMed Central - PubMed

Affiliation: Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America.

ABSTRACT
The effects of Corexit 9500A (CE) on respiratory epithelial surfaces of terrestrial mammals and marine animals are largely unknown. This study investigated the role of CE-induced heme oxygenase-1 (HO-1), a cytoprotective enzyme with anti-apoptotic and antioxidant activity, in human bronchial airway epithelium and the gills of exposed aquatic animals. We evaluated CE-mediated alterations in human airway epithelial cells, mice lungs and gills from zebrafish and blue crabs. Our results demonstrated that CE induced an increase in gill epithelial edema and human epithelial monolayer permeability, suggesting an acute injury caused by CE exposure. CE induced the expression of HO-1 as well as C-reactive protein (CRP) and NADPH oxidase 4 (NOX4), which are associated with ROS production. Importantly, CE induced caspase-3 activation and subsequent apoptosis of epithelial cells. The expression of the intercellular junctional proteins, such as tight junction proteins occludin, zonula occludens (ZO-1), ZO-2 and adherens junctional proteins E-cadherin and Focal Adhesion Kinase (FAK), were remarkably inhibited by CE, suggesting that these proteins are involved in CE-induced increased permeability and subsequent apoptosis. The cytoskeletal protein F-actin was also disrupted by CE. Treatment with carbon monoxide releasing molecule-2 (CORM-2) significantly inhibited CE-induced ROS production, while the addition of HO-1 inhibitor, significantly increased CE-induced ROS production and apoptosis, suggesting a protective role of HO-1 or its reaction product, CO, in CE-induced apoptosis. Using HO-1 knockout mice, we further demonstrated that HO-1 protected against CE-induced inflammation and cellular apoptosis and corrected CE-mediated inhibition of E-cadherin and FAK. These observations suggest that CE activates CRP and NOX4-mediated ROS production, alters permeability by inhibition of junctional proteins, and leads to caspase-3 dependent apoptosis of epithelial cells, while HO-1 and its reaction products protect against oxidative stress and apoptosis.

No MeSH data available.


Related in: MedlinePlus