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Biochem Biophys Res Commun. 2013 Aug 23;438(2):249-56. doi: 10.1016/j.bbrc.2013.07.006. Epub 2013 Jul 11.

Differential COX-2 induction by viral and bacterial PAMPs: Consequences for cytokine and interferon responses and implications for anti-viral COX-2 directed therapies.

Author information

1
National Heart & Lung Institute, Imperial College London, UK. n.kirkby@imperial.ac.uk

Abstract

Cyclooxygenase 2 (COX)-2 is induced by bacterial and viral infections and has complex, poorly understood roles in anti-pathogen immunity. Here, we use a knock-in luciferase reporter model to image Cox2 expression across a range of tissues in mice following treatment with the either the prototypical bacterial pathogen-associated molecular pattern (PAMP), LPS, which activates Toll-like receptor (TLR)4, or with poly(I:C), a viral PAMP, which activates TLR3. LPS induced Cox2 expression in all tissues examined. In contrast, poly(I:C) elicited a milder response, limited to a subset of tissues. A panel of cytokines and interferons was measured in plasma of wild-type, Cox1(-/-) and Cox2(-/-) mice treated with LPS, poly(I:C), MALP2 (TLR2/6), Pam3CSK4 (TLR2/1), R-848 (TLR7/8) or CpG ODN (TLR9), to establish whether/how each COX isoform modulates specific PAMP/TLR responses. Only LPS induced notable loss of condition in mice (inactivity, hunching, piloerection). However, all TLR agonists produced cytokine responses, many of which were modulated in specific fashions by Cox1 or Cox2 gene deletion. Notably we observed opposing effects of Cox2 gene deletion on the responses to the bacterial PAMP, LPS, and the viral PAMP, poly(I:C), consistent with the differing abilities of the PAMPs to induce Cox2 expression. Cox2 gene deletion limited the plasma IL-1β and interferon-γ responses and hypothermia produced by LPS. In contrast, in response to poly(I:C), Cox2(-/-) mice exhibited enhanced plasma interferon (IFNα,β,γ,λ) and related cytokine responses (IP-10, IL-12). These observations suggest that a COX-2 selective inhibitor, given early in infection, may enhance and/or prolong endogenous interferon responses, and thereby increase anti-viral immunity.

KEYWORDS:

Cyclooxygenase; LPS; Poly(I:C); TLR3; TLR4; Toll-like receptor

PMID:
23850620
PMCID:
PMC3759847
DOI:
10.1016/j.bbrc.2013.07.006
[Indexed for MEDLINE]
Free PMC Article
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