AMP-activated protein kinase deficiency reduces ozone-induced lung injury and oxidative stress in mice
<p>Abstract</p> <p>Background</p> <p>Acute ozone exposure causes lung oxidative stress and inflammation leading to lung injury. At least one mechanism underlying the lung toxicity of ozone involves excessive production of reactive oxygen and nitrogen intermediates such...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2011-05-01
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| Series: | Respiratory Research |
| Online Access: | http://respiratory-research.com/content/12/1/64 |
| _version_ | 1818791310661779456 |
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| author | Jean Lancel Steve Tiesset Hélène Hulo Sébastien Viollet Benoit Sobaszek Annie Nevière Rémi |
| author_facet | Jean Lancel Steve Tiesset Hélène Hulo Sébastien Viollet Benoit Sobaszek Annie Nevière Rémi |
| author_sort | Jean |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Acute ozone exposure causes lung oxidative stress and inflammation leading to lung injury. At least one mechanism underlying the lung toxicity of ozone involves excessive production of reactive oxygen and nitrogen intermediates such as peroxynitrite. In addition and beyond its major prooxidant properties, peroxynitrite may nitrate tyrosine residues altering phosphorylation of many protein kinases involved in cell signalling. It was recently proposed that peroxynitrite activates 5'-AMP-activated kinase (AMPK), which regulates metabolic pathways and the response to cell stress. AMPK activation as a consequence of ozone exposure has not been previously evaluated. First, we tested whether acute ozone exposure in mice would impair alveolar fluid clearance, increase lung tissue peroxynitrite production and activate AMPK. Second, we tested whether loss of AMP-activated protein kinase alpha1 subunit in mouse would prevent enhanced oxidative stress and lung injury induced by ozone exposure.</p> <p>Methods</p> <p>Control and AMPKα1 deficient mice were exposed to ozone at a concentration of 2.0 ppm for 3 h in glass cages. Evaluation was performed 24 h after ozone exposure. Alveolar fluid clearance (AFC) was evaluated using fluorescein isothiocyanate tagged albumin. Differential cell counts, total protein levels, cytokine concentrations, myeloperoxidase activity and markers of oxidative stress, i.e. malondialdehyde and peroxynitrite, were determined in bronchoalveolar lavage (BAL) and lung homogenates (LH). Levels of AMPK-Thr<sup>172 </sup>phosphorylation and basolateral membrane Na(+)-K(+)-ATPase abundance were determined by Western blot.</p> <p>Results</p> <p>In control mice, ozone exposure induced lung inflammation as evidence by increased leukocyte count, protein concentration in BAL and myeloperoxidase activity, pro-inflammatory cytokine levels in LH. Increases in peroxynitrite levels (3 vs 4.4 nM, p = 0.02) and malondialdehyde concentrations (110 vs 230 μmole/g wet tissue) were detected in LH obtained from ozone-exposed control mice. Ozone exposure consistently increased phosphorylated AMPK-Thr<sup>172 </sup>to total AMPK ratio by 80% in control mice. Ozone exposure causes increases in AFC and basolateral membrane Na(+)-K(+)-ATPase abundance in control mice which did not occur in AMPKα1 deficient mice.</p> <p>Conclusions</p> <p>Our results collectively suggest that AMPK activation participates in ozone-induced increases in AFC, inflammation and oxidative stress. Further studies are needed to understand how the AMPK pathway may provide a novel approach for the prevention of ozone-induced lung injury.</p> |
| first_indexed | 2024-12-18T15:09:19Z |
| format | Article |
| id | doaj.art-a82526fec8a14e43a3ed349aefcc3ea2 |
| institution | Directory Open Access Journal |
| issn | 1465-9921 |
| language | English |
| last_indexed | 2024-12-18T15:09:19Z |
| publishDate | 2011-05-01 |
| publisher | BMC |
| record_format | Article |
| series | Respiratory Research |
| spelling | doaj.art-a82526fec8a14e43a3ed349aefcc3ea22022-12-21T21:03:42ZengBMCRespiratory Research1465-99212011-05-011216410.1186/1465-9921-12-64AMP-activated protein kinase deficiency reduces ozone-induced lung injury and oxidative stress in miceJeanLancel SteveTiesset HélèneHulo SébastienViollet BenoitSobaszek AnnieNevière Rémi<p>Abstract</p> <p>Background</p> <p>Acute ozone exposure causes lung oxidative stress and inflammation leading to lung injury. At least one mechanism underlying the lung toxicity of ozone involves excessive production of reactive oxygen and nitrogen intermediates such as peroxynitrite. In addition and beyond its major prooxidant properties, peroxynitrite may nitrate tyrosine residues altering phosphorylation of many protein kinases involved in cell signalling. It was recently proposed that peroxynitrite activates 5'-AMP-activated kinase (AMPK), which regulates metabolic pathways and the response to cell stress. AMPK activation as a consequence of ozone exposure has not been previously evaluated. First, we tested whether acute ozone exposure in mice would impair alveolar fluid clearance, increase lung tissue peroxynitrite production and activate AMPK. Second, we tested whether loss of AMP-activated protein kinase alpha1 subunit in mouse would prevent enhanced oxidative stress and lung injury induced by ozone exposure.</p> <p>Methods</p> <p>Control and AMPKα1 deficient mice were exposed to ozone at a concentration of 2.0 ppm for 3 h in glass cages. Evaluation was performed 24 h after ozone exposure. Alveolar fluid clearance (AFC) was evaluated using fluorescein isothiocyanate tagged albumin. Differential cell counts, total protein levels, cytokine concentrations, myeloperoxidase activity and markers of oxidative stress, i.e. malondialdehyde and peroxynitrite, were determined in bronchoalveolar lavage (BAL) and lung homogenates (LH). Levels of AMPK-Thr<sup>172 </sup>phosphorylation and basolateral membrane Na(+)-K(+)-ATPase abundance were determined by Western blot.</p> <p>Results</p> <p>In control mice, ozone exposure induced lung inflammation as evidence by increased leukocyte count, protein concentration in BAL and myeloperoxidase activity, pro-inflammatory cytokine levels in LH. Increases in peroxynitrite levels (3 vs 4.4 nM, p = 0.02) and malondialdehyde concentrations (110 vs 230 μmole/g wet tissue) were detected in LH obtained from ozone-exposed control mice. Ozone exposure consistently increased phosphorylated AMPK-Thr<sup>172 </sup>to total AMPK ratio by 80% in control mice. Ozone exposure causes increases in AFC and basolateral membrane Na(+)-K(+)-ATPase abundance in control mice which did not occur in AMPKα1 deficient mice.</p> <p>Conclusions</p> <p>Our results collectively suggest that AMPK activation participates in ozone-induced increases in AFC, inflammation and oxidative stress. Further studies are needed to understand how the AMPK pathway may provide a novel approach for the prevention of ozone-induced lung injury.</p>http://respiratory-research.com/content/12/1/64 |
| spellingShingle | Jean Lancel Steve Tiesset Hélène Hulo Sébastien Viollet Benoit Sobaszek Annie Nevière Rémi AMP-activated protein kinase deficiency reduces ozone-induced lung injury and oxidative stress in mice Respiratory Research |
| title | AMP-activated protein kinase deficiency reduces ozone-induced lung injury and oxidative stress in mice |
| title_full | AMP-activated protein kinase deficiency reduces ozone-induced lung injury and oxidative stress in mice |
| title_fullStr | AMP-activated protein kinase deficiency reduces ozone-induced lung injury and oxidative stress in mice |
| title_full_unstemmed | AMP-activated protein kinase deficiency reduces ozone-induced lung injury and oxidative stress in mice |
| title_short | AMP-activated protein kinase deficiency reduces ozone-induced lung injury and oxidative stress in mice |
| title_sort | amp activated protein kinase deficiency reduces ozone induced lung injury and oxidative stress in mice |
| url | http://respiratory-research.com/content/12/1/64 |
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