tetano
Editor, Senior Moderator
Sci Rep. 2016 Jun 6;6:27275. doi: 10.1038/srep27275.
[h=1]Influenza A viruses suppress cyclooxygenase-2 expression by affecting its mRNA stability.[/h] Dudek SE[SUP]1,[/SUP][SUP]2[/SUP], Nitzsche K[SUP]2,[/SUP][SUP]2[/SUP], Ludwig S[SUP]2,[/SUP][SUP]2,[/SUP][SUP]2[/SUP], Ehrhardt C[SUP]2,[/SUP][SUP]2[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Infection with influenza A viruses (IAV) provokes activation of cellular defence mechanisms contributing to the innate immune and inflammatory response. In this process the cyclooxygenase-2 (COX-2) plays an important role in the induction of prostaglandin-dependent inflammation. While it has been reported that COX-2 is induced upon IAV infection, in the present study we observed a down-regulation at later stages of infection suggesting a tight regulation of COX-2 by IAV. Our data indicate the pattern-recognition receptor RIG-I as mediator of the initial IAV-induced COX-2 synthesis. Nonetheless, during on-going IAV replication substantial suppression of COX-2 mRNA and protein synthesis could be detected, accompanied by a decrease in mRNA half-life. Interestingly, COX-2 mRNA stability was not only imbalanced by IAV replication but also by stimulation of cells with viral RNA. Our results reveal tristetraprolin (TTP), which is known to bind COX-2 mRNA and promote its rapid degradation, as regulator of COX-2 expression in IAV infection. During IAV replication and viral RNA accumulation TTP mRNA synthesis was induced, resulting in reduced COX-2 levels. Accordingly, the down-regulation of TTP resulted in increased COX-2 protein expression after IAV infection. These findings indicate a novel IAV-regulated cellular mechanism, contributing to the repression of host defence and therefore facilitating viral replication.
PMID: 27265729 [PubMed - in process] Free full text
[h=1]Influenza A viruses suppress cyclooxygenase-2 expression by affecting its mRNA stability.[/h] Dudek SE[SUP]1,[/SUP][SUP]2[/SUP], Nitzsche K[SUP]2,[/SUP][SUP]2[/SUP], Ludwig S[SUP]2,[/SUP][SUP]2,[/SUP][SUP]2[/SUP], Ehrhardt C[SUP]2,[/SUP][SUP]2[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Infection with influenza A viruses (IAV) provokes activation of cellular defence mechanisms contributing to the innate immune and inflammatory response. In this process the cyclooxygenase-2 (COX-2) plays an important role in the induction of prostaglandin-dependent inflammation. While it has been reported that COX-2 is induced upon IAV infection, in the present study we observed a down-regulation at later stages of infection suggesting a tight regulation of COX-2 by IAV. Our data indicate the pattern-recognition receptor RIG-I as mediator of the initial IAV-induced COX-2 synthesis. Nonetheless, during on-going IAV replication substantial suppression of COX-2 mRNA and protein synthesis could be detected, accompanied by a decrease in mRNA half-life. Interestingly, COX-2 mRNA stability was not only imbalanced by IAV replication but also by stimulation of cells with viral RNA. Our results reveal tristetraprolin (TTP), which is known to bind COX-2 mRNA and promote its rapid degradation, as regulator of COX-2 expression in IAV infection. During IAV replication and viral RNA accumulation TTP mRNA synthesis was induced, resulting in reduced COX-2 levels. Accordingly, the down-regulation of TTP resulted in increased COX-2 protein expression after IAV infection. These findings indicate a novel IAV-regulated cellular mechanism, contributing to the repression of host defence and therefore facilitating viral replication.
PMID: 27265729 [PubMed - in process] Free full text