Essential Role of Interferon Regulatory Factor 3 in Direct Activation of RANTES Chemokine Transcription

Toll-IL-1R domain-containing adaptor-inducing IFN-β (TRIF) is an adaptor molecule that mediates a distinct TLR signaling pathway. Roles of TRIF in the host defense have been primarily associated with virus infections owing to the induction of IFN-αβ. In this study, we investigated a role of TRIF in Pseudomonas aeruginosa infection. In vitro, TRIF-deficient mouse alveolar and peritoneal macrophages showed a complete inhibition of RANTES (CCL5) production, severely impaired TNF and KC (CXCL1) production, and reduced NF-κB activation in response to P. aeruginosa stimulation. In vivo, TRIF-deficient mice showed a complete inhibition of RANTES production, a severely impaired TNF and KC production, and an efficient MIP-2 and IL-1β production in the lung following P. aeruginosa infection. This outcome was associated with a delayed recruitment of neutrophils into the airways. These results suggest that TRIF mediates a distinct cytokine/chemokine profile in response to P. aeruginosa infection. P. aeruginosa-induced RANTES production is completely dependent on TRIF pathway in mice. Importantly, TRIF deficiency leads to impaired clearance of P. aeruginosa from the lung during the initial 24–48 h of infection. Thus, TRIF represents a novel mechanism involved in the development of host response to P. aeruginosa infection.

Section: Figurementioning

confidence: 99%

A Role of Toll-IL-1 Receptor Domain-Containing Adaptor-Inducing IFN-β in the Host Response to Pseudomonas aeruginosa Lung Infection in Mice

Power¹,

Li²,

Yamamoto

et al. 2007

“…This implies that the activation of NF-B is at least partially responsible for the saturated fatty acid-induced CD86 up-regulation. The activation of IRF3 through TRIF pathways is known to induce the expression of target genes with the ISRE binding site in the promoter regions (20,21). Both murine and human CD86-luciferase activity induced by lauric acid was inhibited by the IRF3 (DN) (Fig.…”

Section: Transcriptional Activity Of Cd86 Promoter Is Differentially mentioning

confidence: 99%

Saturated and Polyunsaturated Fatty Acids Reciprocally Modulate Dendritic Cell Functions Mediated through TLR4

Weatherill

Lee

Zhao

et al. 2005

274

204

TLRs provide critical signals to induce innate immune responses in APCs such as dendritic cells (DCs) that in turn link to adaptive immune responses. Results from our previous studies demonstrated that saturated fatty acids activate TLRs, whereas n-3 polyunsaturated fatty acids inhibit agonist-induced TLR activation. These results raise a significant question as to whether fatty acids differentially modulate immune responses mediated through TLR activation. The results presented in this study demonstrate that the saturated fatty acid, lauric acid, up-regulates the expression of costimulatory molecules (CD40, CD80, and CD86), MHC class II, and cytokines (IL-12p70 and IL-6) in bone marrow-derived DCs. The dominant negative mutant of TLR4 or its downstream signaling components inhibits lauric acid-induced expression of a CD86 promoter-reporter gene. In contrast, an n-3 polyunsaturated fatty acid, docosahexaenoic acid, inhibits TLR4 agonist (LPS)-induced up-regulation of the costimulatory molecules, MHC class II, and cytokine production. Similarly, DCs treated with lauric acid show increased T cell activation capacity, whereas docosahexaenoic acid inhibits T cell activation induced by LPS-treated DCs. Together, our results demonstrate that the reciprocal modulation of both innate and adaptive immune responses by saturated fatty acid and n-3 polyunsaturated fatty acid is mediated at least in part through TLRs. These results imply that TLRs are involved in sterile inflammation and immune responses induced by nonmicrobial endogenous molecules. These results shed new light in understanding how types of dietary fatty acids differentially modulate immune responses that could alter the risk of many chronic diseases.

“…Recent studies demonstrated that in response to virus infection, type I IFN gene activation required IRF-3 and IRF-7 gene products as direct transcriptional regulators, but played different roles in the induction of immediate-early vs delayed type I IFN gene (22,23). Previously, we demonstrated that IRF-3 plays a primary role in the Sendai virus-inducible activation of the human RANTES gene (24), based on the following data: 1) Tet-inducible expression of a constitutively activated phosphomimetic form of IRF-3 increased endogenous RANTES mRNA levels, mediated through the ISRE domain located between nucleotide Ϫ126 to Ϫ92 in the RANTES promoter (Fig. 1B); 2) mutations of the ISRE domain blocked virusmediated activation of RANTES promoter; and 3) a dominant negative mutant of IRF-3 repressed virus-induced transcription of endogenous RANTES mRNA.…”

Section: Regulation Of Rantes Chemokine Gene Expression Requiresmentioning

confidence: 99%

“…1B) were prepared by cloning BglII-SalI fragment (Ϫ397 to ϩ5, filled in with Klenow enzyme) from RANTES/chloramphenicol acetyltransferase reporter plasmid (25) into the NheI site (filled in with Klenow enzyme) of the pGL3-basic vector, as previously described (24). The IRF-3, IRF-7, p65/p50, and CBP expression plasmids used in cotransfection experiments have been previously described (24,26).…”

Section: Plasmid Constructions and Mutagenesismentioning

confidence: 99%

“…The 293 cells stably expressing either IRF-3, IRF-3(⌬N), IRF-7, or I B␣-2N were described previously (24,25,27). Transfections for luciferase assay were conducted in human embryonic kidney 293 cells grown in ␣MEM media (Life Technologies, Burlington, Canada) supplemented with 10% FBS, glutamine, and antibiotics.…”

Section: Cell Culture Transfections and Luciferase Assaysmentioning

confidence: 99%

See 1 more Smart Citation

Regulation of RANTES Chemokine Gene Expression Requires Cooperativity Between NF-κB and IFN-Regulatory Factor Transcription Factors

Génin

Algarté

Roof

et al. 2000

Self Cite

206

208

Virus infection of host cells activates a set of cellular genes, including cytokines, IFNs, and chemokines, involved in antiviral defense and immune activation. Previous studies demonstrated that virus-induced transcriptional activation of a member of the human CC-chemokine RANTES required activation of the latent transcription factors IFN-regulatory factor (IRF)-3 and NF-κB via posttranslational phosphorylation. In the present study, we further characterized the regulatory control of RANTES transcription during virus infection using in vivo genomic footprinting analyses. IRF-3, the related IRF-7, and NF-κB are identified as important in vivo binding factors required for the cooperative induction of RANTES transcription after virus infection. Using fibroblastic or myeloid cells, we demonstrate that the kinetics and strength of RANTES virus-induced transcription are highly dependent on the preexistence of IRFs and NF-κB. Use of dominant negative mutants of either IκB-α or IRF-3 demonstrate that disruption of either pathway dramatically abolishes the ability of the other to bind and activate RANTES expression. Furthermore, coexpression of IRF-3, IRF-7, and p65/p50 leads to synergistic activation of RANTES promoter transcription. These studies reveal a model of virus-mediated RANTES promoter activation that involves cooperative synergism between IRF-3/IRF-7 and NF-κB factors.