Double-stranded RNA upregulates the expression of inflammatory mediators in human aortic valve cells through the TLR3-TRIF-noncanonical NF-{kappa}B pathway

The objective of this study is to determine the effect of dsRNA on AVIC inflammatory responses and the underlying mechanism. AVICs from normal human aortic valves were stimulated with polyinosinic-polycytidylic acid [poly(I:C)], a mimic of dsRNA. Poly(I:C) increased the production of IL-6, IL-8, monocyte chemoattractant protein-1, and ICAM-1. Poly(I:C) also induced robust activation of ERK1/2 and NF-B. Knockdown of Toll-like receptor 3 (TLR3) or Toll-IL-1 receptor domain-containing adapter-inducing IFN-β (TRIF) suppressed ERK1/2 and NF-B p65 phosphorylation and reduced inflammatory mediator production induced by poly(I:C). Inhibition of NF-B, not ERK1/2, reduced inflammatory mediator production in AVICs exposed to poly(I:C). Interestingly, inhibition of NF-B by prevention of p50 migration failed to suppress inflammatory mediator production. NF-B p65 intranuclear translocation induced by the TLR4 agonist was reduced by inhibition of p50 migration; however, poly(I:C)-induced p65 translocation was not, although the p65/p50 heterodimer is present in AVICs. Poly(I:C) upregulates the production of multiple inflammatory mediators through the TLR3-TRIF-NF-B pathway in human AVICs. The NF-B activated by dsRNA appears not to be the canonical p65/p50 heterodimers.
Source: AJP: Cell Physiology - Category: Cytology Authors: Tags: RESEARCH ARTICLE Source Type: research