Cytokine and chemokine secretion induced by poly(I:C) through NF-κB and phosphoinositide 3-kinase signaling pathways in human corneal fibroblasts

Purpose/Aim: Viral infection of the cornea can result in inflammation and scarring and eventually lead to blindness. Polyinosinic-polycytidylic acid [poly(I:C)], an analog of viral double-stranded RNA, induces the secretion of cytokines and chemokines from cultured corneal fibroblasts. We have now investigated the role of nuclear factor (NF)-κB and phosphoinositide 3-kinase (PI3K) signaling pathways in poly(I:C)-induced cytokine and chemokine secretion from corneal fibroblasts. Materials and Methods: Human corneal fibroblasts were cultured with poly(I:C) in the absence or presence of IKK-2 inhibitor or LY294002, which are inhibitors of NF-κB and PI3K signaling, respectively. The release of the pro-inflammatory cytokine interleukin (IL)-6 and the chemokines IL-8, IP-10, and RANTES from the cells was measured with an enzyme-linked immunosorbent assay. Results: Poly(I:C) induced the secretion of IL-6, IL-8, IP-10, and RANTES from corneal fibroblasts. Whereas the poly(I:C)-induced secretion of IL-6, IP-10, and RANTES was inhibited by both IKK-2 inhibitor and LY294002, that of IL-8 was blocked only by IKK-2 inhibitor. Conclusions: The poly(I:C)-induced secretion of IL-6, IP-10, and RANTES from human corneal fibroblasts is mediated by both NF-κB and PI3K signaling pathways, whereas that of IL-8 is mediated by the NF-κB pathway. These signaling pathways thus likely contribute to local inflammation in the corneal stroma induced by viral infection.