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Am J Respir Crit Care Med. 2010 Jul 15;182(2):170-82. doi: 10.1164/rccm.200907-1047OC. Epub 2010 Mar 11.

Nrf2-regulated PPAR{gamma} expression is critical to protection against acute lung injury in mice.

Author information

1
Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Dr., Building 101, MD D-201, Research Triangle Park, NC 27709, USA. cho2@niehs.nih.gov

Abstract

RATIONALE:

The NF-E2 related factor 2 (Nrf2)-antioxidant response element (ARE) pathway is essential for protection against oxidative injury and inflammation including hyperoxia-induced acute lung injury. Microarray expression profiling revealed that lung peroxisome proliferator activated receptor gamma (PPARgamma) induction is suppressed in hyperoxia-susceptible Nrf2-deficient (Nrf2(-/-)) mice compared with wild-type (Nrf2(+/+)) mice. PPARgamma has pleiotropic beneficial effects including antiinflammation in multiple tissues.

OBJECTIVES:

We tested the hypothesis that PPARgamma is an important determinant of pulmonary responsivity to hyperoxia regulated by Nrf2.

METHODS:

A computational bioinformatic method was applied to screen potential AREs in the Pparg promoter for Nrf2 binding. The functional role of a potential ARE was investigated by in vitro promoter analysis. A role for PPARgamma in hyperoxia-induced acute lung injury was determined by temporal silencing of PPARgamma via intranasal delivery of PPARgamma-specific interference RNA and by administration of a PPARgamma ligand 15-deoxy-Delta(12,14)-prostaglandin J(2) in mice.

MEASUREMENTS AND MAIN RESULTS:

Deletion or site-directed mutagenesis of a potential ARE spanning -784/-764 sequence significantly attenuated hyperoxia-increased Pparg promoter activity in airway epithelial cells overexpressing Nrf2, indicating that the -784/-764 ARE is critical for Nrf2-regulated PPARgamma expression. Mice with decreased lung PPARgamma by specific interference RNA treatment had significantly augmented hyperoxia-induced pulmonary inflammation and injury. 15 Deoxy-Delta(12,14)-prostaglandin J(2) administration significantly reduced hyperoxia-induced lung inflammation and edema in Nrf2(+/+), but not in Nrf2(-/-) mice.

CONCLUSIONS:

Results indicate for the first time that Nrf2-driven PPARgamma induction has an essential protective role in pulmonary oxidant injury. Our observations provide new insights into the therapeutic potential of PPARgamma in airway oxidative inflammatory disorders.

PMID:
20224069
PMCID:
PMC2913232
DOI:
10.1164/rccm.200907-1047OC
[Indexed for MEDLINE]
Free PMC Article

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