FEBS Lett. 2004 Apr 9;563(1-3):223-8
Auch CJ, Saha RN, Sheikh FG, Liu X, Jacobs BL, Pahan K.
Department of Oral Biology, University of Nebraska Medical Center, Lincoln, NE 68583-0740, USA.
Environmental factor(s), such as viral infection, has been implicated as one of the triggering events leading to neuroinflammation in multiple sclerosis.
This study underlines the importance of double-stranded RNA (dsRNA), the active component of a viral infection, in inducing the expression of inducible nitric oxide synthase (iNOS) in human astroglia.
DsRNA in the form of synthetic polyinosinic-polycytidylic acid (poly IC) induced expression of iNOS and iNOS promoter-driven luciferase activity through activation of nuclear factor (NF)-kappaB and CCAAT/enhancer-binding proteinbeta (C/EBPbeta).
In addition, we show that inhibitors of protein kinase R attenuated iNOS by suppressing the activation of NF-kappaB but not C/EBPbeta.
In contrast, knock down of p38 mitogen-activated protein kinase (MAPK) attenuated iNOS by suppressing the activation of C/EBPbeta but not NF-kappaB.
This study delineates a novel role of dsRNA in inducing the expression of iNOS through dsRNA-activated protein kinase (PKR)-mediated activation of NF-kappaB and p38-mediated activation of C/EBPbeta in human astroglia that may participate in virus-induced neurological abnormalities.