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RIG-I is required for the inhibition of measles virus by retinoids.

Soye KJ, Trottier C, Richardson CD, Ward BJ, Miller WH - PLoS ONE (2011)

Bottom Line: Vitamin A can significantly decrease measles-associated morbidity and mortality.Retinoid signaling was also found to act in combination with IFN to induce high levels of RIG-I expression.IRF-1 is known to be regulated by retinoids and MeV, but we found recruitment of IRF-1 to the RIG-I promoter by retinoids alone.

View Article: PubMed Central - PubMed

Affiliation: McGill University Health Center Research Institute, Department of Infectious Diseases, McGill University, Montreal, Quebec, Canada.

ABSTRACT
Vitamin A can significantly decrease measles-associated morbidity and mortality. Vitamin A can inhibit the replication of measles virus (MeV) in vitro through an RARα- and type I interferon (IFN)-dependent mechanism. Retinoid-induced gene I (RIG-I) expression is induced by retinoids, activated by MeV RNA and is important for IFN signaling. We hypothesized that RIG-I is central to retinoid-mediated inhibition of MeV in vitro. We demonstrate that RIG-I expression is increased in cells treated with retinoids and infected with MeV. The central role of RIG-I in the retinoid-anti-MeV effect was demonstrated in the Huh-7/7.5 model; the latter cells having non-functional RIG-I. RAR-dependent retinoid signaling was required for the induction of RIG-I by retinoids and MeV. Retinoid signaling was also found to act in combination with IFN to induce high levels of RIG-I expression. RIG-I promoter activation required both retinoids and MeV, as indicated by markers of active chromatin. IRF-1 is known to be regulated by retinoids and MeV, but we found recruitment of IRF-1 to the RIG-I promoter by retinoids alone. Using luciferase expression constructs, we further demonstrated that the IRF-1 response element of RIG-I was required for RIG-I activation by retinoids or IFN. These results reveal that retinoid treatment and MeV infection induces significant RIG-I. RIG-I is required for the retinoid-MeV antiviral response. The induction is dependent on IFN, retinoids and IRF-1.

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RIG-I necessary for inhibition of MeV by ATRA.(A) Huh7 and Huh7.5 cells were infected MeV at an MOI of 0.01 and treated with 1 µM ATRA or DMSO. Whole cell lysates were harvested after 48 hours and viral titers were measured by plaque assay. (B) Huh7 cells were infected with MeV at an MOI of 0.01 and treated with 1 µM ATRA or DMSO and transfected with the control plasmid or RIG-I dominant negative (RIG-IC) expression construct. Whole cell lysates were harvested after 48 hours and viral titers were measured by plaque assay. (C) Huh7.5 cells were transfected with the control plasmid or RIG-I expression construct and infected with MeV at an MOI of 0.01. Whole cell lysates were harvested after 48hr and viral titers were measured by plaque assay. Data represent two experiments performed in triplicate (N = 2). **p<0.01, ***p<0.001.
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pone-0022323-g002: RIG-I necessary for inhibition of MeV by ATRA.(A) Huh7 and Huh7.5 cells were infected MeV at an MOI of 0.01 and treated with 1 µM ATRA or DMSO. Whole cell lysates were harvested after 48 hours and viral titers were measured by plaque assay. (B) Huh7 cells were infected with MeV at an MOI of 0.01 and treated with 1 µM ATRA or DMSO and transfected with the control plasmid or RIG-I dominant negative (RIG-IC) expression construct. Whole cell lysates were harvested after 48 hours and viral titers were measured by plaque assay. (C) Huh7.5 cells were transfected with the control plasmid or RIG-I expression construct and infected with MeV at an MOI of 0.01. Whole cell lysates were harvested after 48hr and viral titers were measured by plaque assay. Data represent two experiments performed in triplicate (N = 2). **p<0.01, ***p<0.001.

Mentions: As expected in the Huh-7/7.5 system, Huh-7.5 cells with non-functional RIG-I permitted higher levels of viral replication compared to the RIG-I functional Huh-7 cells (Figure 2A). Levels of RIG-I mRNA and protein are comparable in both cell lines (data not shown). ATRA treatment significantly inhibited MeV production in Huh-7 cells but had no effect in Huh-7.5 cells (Figure 2A), suggesting that RIG-I has a central role in the inhibitory effect of retinoids.


RIG-I is required for the inhibition of measles virus by retinoids.

Soye KJ, Trottier C, Richardson CD, Ward BJ, Miller WH - PLoS ONE (2011)

RIG-I necessary for inhibition of MeV by ATRA.(A) Huh7 and Huh7.5 cells were infected MeV at an MOI of 0.01 and treated with 1 µM ATRA or DMSO. Whole cell lysates were harvested after 48 hours and viral titers were measured by plaque assay. (B) Huh7 cells were infected with MeV at an MOI of 0.01 and treated with 1 µM ATRA or DMSO and transfected with the control plasmid or RIG-I dominant negative (RIG-IC) expression construct. Whole cell lysates were harvested after 48 hours and viral titers were measured by plaque assay. (C) Huh7.5 cells were transfected with the control plasmid or RIG-I expression construct and infected with MeV at an MOI of 0.01. Whole cell lysates were harvested after 48hr and viral titers were measured by plaque assay. Data represent two experiments performed in triplicate (N = 2). **p<0.01, ***p<0.001.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3139622&req=5

pone-0022323-g002: RIG-I necessary for inhibition of MeV by ATRA.(A) Huh7 and Huh7.5 cells were infected MeV at an MOI of 0.01 and treated with 1 µM ATRA or DMSO. Whole cell lysates were harvested after 48 hours and viral titers were measured by plaque assay. (B) Huh7 cells were infected with MeV at an MOI of 0.01 and treated with 1 µM ATRA or DMSO and transfected with the control plasmid or RIG-I dominant negative (RIG-IC) expression construct. Whole cell lysates were harvested after 48 hours and viral titers were measured by plaque assay. (C) Huh7.5 cells were transfected with the control plasmid or RIG-I expression construct and infected with MeV at an MOI of 0.01. Whole cell lysates were harvested after 48hr and viral titers were measured by plaque assay. Data represent two experiments performed in triplicate (N = 2). **p<0.01, ***p<0.001.
Mentions: As expected in the Huh-7/7.5 system, Huh-7.5 cells with non-functional RIG-I permitted higher levels of viral replication compared to the RIG-I functional Huh-7 cells (Figure 2A). Levels of RIG-I mRNA and protein are comparable in both cell lines (data not shown). ATRA treatment significantly inhibited MeV production in Huh-7 cells but had no effect in Huh-7.5 cells (Figure 2A), suggesting that RIG-I has a central role in the inhibitory effect of retinoids.

Bottom Line: Vitamin A can significantly decrease measles-associated morbidity and mortality.Retinoid signaling was also found to act in combination with IFN to induce high levels of RIG-I expression.IRF-1 is known to be regulated by retinoids and MeV, but we found recruitment of IRF-1 to the RIG-I promoter by retinoids alone.

View Article: PubMed Central - PubMed

Affiliation: McGill University Health Center Research Institute, Department of Infectious Diseases, McGill University, Montreal, Quebec, Canada.

ABSTRACT
Vitamin A can significantly decrease measles-associated morbidity and mortality. Vitamin A can inhibit the replication of measles virus (MeV) in vitro through an RARα- and type I interferon (IFN)-dependent mechanism. Retinoid-induced gene I (RIG-I) expression is induced by retinoids, activated by MeV RNA and is important for IFN signaling. We hypothesized that RIG-I is central to retinoid-mediated inhibition of MeV in vitro. We demonstrate that RIG-I expression is increased in cells treated with retinoids and infected with MeV. The central role of RIG-I in the retinoid-anti-MeV effect was demonstrated in the Huh-7/7.5 model; the latter cells having non-functional RIG-I. RAR-dependent retinoid signaling was required for the induction of RIG-I by retinoids and MeV. Retinoid signaling was also found to act in combination with IFN to induce high levels of RIG-I expression. RIG-I promoter activation required both retinoids and MeV, as indicated by markers of active chromatin. IRF-1 is known to be regulated by retinoids and MeV, but we found recruitment of IRF-1 to the RIG-I promoter by retinoids alone. Using luciferase expression constructs, we further demonstrated that the IRF-1 response element of RIG-I was required for RIG-I activation by retinoids or IFN. These results reveal that retinoid treatment and MeV infection induces significant RIG-I. RIG-I is required for the retinoid-MeV antiviral response. The induction is dependent on IFN, retinoids and IRF-1.

Show MeSH
Related in: MedlinePlus