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PLoS One. 2014 Jul 2;9(7):e101263. doi: 10.1371/journal.pone.0101263. eCollection 2014.

Reversible suppression of cyclooxygenase 2 (COX-2) expression in vivo by inducible RNA interference.

Author information

1
Department of Medical and Molecular Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America; Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America.
2
Cold Spring Harbor Laboratory and Howard Hughes Medical Institute, New York, New York, United States of America.

Abstract

Prostaglandin-endoperoxide synthase 2 (PTGS2), also known as cyclooxygenase 2 (COX-2), plays a critical role in many normal physiological functions and modulates a variety of pathological conditions. The ability to turn endogenous COX-2 on and off in a reversible fashion, at specific times and in specific cell types, would be a powerful tool in determining its role in many contexts. To achieve this goal, we took advantage of a recently developed RNA interference system in mice. An shRNA targeting the Cox2 mRNA 3'untranslated region was inserted into a microRNA expression cassette, under the control of a tetracycline response element (TRE) promoter. Transgenic mice containing the COX-2-shRNA were crossed with mice encoding a CAG promoter-driven reverse tetracycline transactivator, which activates the TRE promoter in the presence of tetracycline/doxycycline. To facilitate testing the system, we generated a knockin reporter mouse in which the firefly luciferase gene replaces the Cox2 coding region. Cox2 promoter activation in cultured cells from triple transgenic mice containing the luciferase allele, the shRNA and the transactivator transgene resulted in robust luciferase and COX-2 expression that was reversibly down-regulated by doxycycline administration. In vivo, using a skin inflammation-model, both luciferase and COX-2 expression were inhibited over 80% in mice that received doxycycline in their diet, leading to a significant reduction of infiltrating leukocytes. In summary, using inducible RNA interference to target COX-2 expression, we demonstrate potent, reversible Cox2 gene silencing in vivo. This system should provide a valuable tool to analyze cell type-specific roles for COX-2.

PMID:
24988319
PMCID:
PMC4079684
DOI:
10.1371/journal.pone.0101263
[Indexed for MEDLINE]
Free PMC Article

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