Abstract
Purpose: :
Polyinosinic-polycytidylic acid [poly(I:C)] is an analog of viral double-stranded RNA produced during viral replication. We have previously shown that poly(I:C) increases the expression of cytokines and cell adhesion molecules in human corneal fibroblasts in a manner dependent on mitogen-activated protein kinase (MAPK) signaling. We have now examined the possible role of nuclear factor (NF)-ΚB signaling in these effects of poly(I:C).
Methods: :
Human corneal fibroblasts were cultured with various concentrations of poly (I:C) in the absence or presence of an inhibitor of the IΚB kinase 2 (IKK2) inhibitor. The expression of the adhesion molecules ICAM-1 and VCAM-1 as well as the phosphorylation and degradation of the NF-ΚB-inhibitory protein IΚB- were examined by immunoblot analysis. Release of the pro-inflammatory cytokines interleukin (IL)-6 and IL-8 into the culture medium was measured with assay kits. The subcellular localization of ICAM-1, VCAM-1, and the p65 subunit of NF-ΚB was determined by immunofluorescence analysis.
Results: :
Poly(I:C) induced the phosphorylation and degradation of IΚB- as well as the nuclear translocation of the p65 subunit of NF-ΚB. The release of IL-6 and IL-8 as well as the expression of ICAM-1 and VCAM-1 induced by poly(I:C) were inhibited by IKK2 inhibitor in a concentration- and time-dependent manner. The inhibitor also induced a decrease in the levels of ICAM-1 and VCAM-1 immunofluorescence at the cell surface.
Conclusions: :
The NF-ΚB signaling pathway contributes to local immune and inflammatory responses to viral infection in the corneal stroma.
Keywords: cornea: stroma and keratocytes • signal transduction