Poly(I:C)-induced adhesion molecule expression mediated by NF-{kappa}B and phosphoinositide 3-kinase-Akt signaling pathways in human corneal fibroblasts.
OBJECTIVE
Viral infection at the ocular surface can lead to the chronic condition of viral stromal keratitis. Polyinosinic-polycytidylic acid [poly(I:C)], an analog of viral double-stranded RNA, induces the expression of adhesion molecules in cultured corneal fibroblasts. The authors investigated the roles of nuclear factor (NF)-κB and phosphoinositide 3-kinase (PI3K)-Akt signaling pathways in the poly(I:C)-induced expression of adhesion molecules in corneal fibroblasts.


METHODS
Human corneal fibroblasts were cultured with poly(I:C) in the absence or presence of IκB kinase 2 (IKK2) inhibitor (an inhibitor of NF-κB activation) or the PI3K inhibitor LY294002. The expression of vascular cell adhesion molecule (VCAM)-1, intercellular adhesion molecule (ICAM)-1, ICAM-2, and E-selectin, as well as the phosphorylation of the NF-κB inhibitory protein IκB-α and Akt, were examined by immunoblot analysis. The subcellular localization of adhesion molecules was determined by immunofluorescence analysis.


RESULTS
Poly(I:C) increased the expression of VCAM-1 and ICAM-1 but not that of ICAM-2 or E-selectin in corneal fibroblasts. Poly(I:C) also induced the phosphorylation of IκB-α and Akt. The poly(I:C)-induced expression of VCAM-1 and ICAM-1 was attenuated by both IKK2 inhibitor and LY294002.


CONCLUSIONS
The NF-κB and PI3K-Akt signaling pathways mediate the poly(I:C)-induced upregulation of VCAM-1 and ICAM-1 in corneal fibroblasts, with PI3K acting upstream of NF-κB activation. These pathways thus likely modulate local immune and inflammatory responses to viral infection in the corneal stroma.
Orita
Tomoko
T
Department of Ophthalmology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan.
Kimura
Kazuhiro
K
Zhou
Hong-Yan
HY
Nishida
Teruo
T
D015703:Antigens, CD / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D003315:Cornea / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D019040:E-Selectin / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D051550:I-kappa B Kinase / Q000494:pharmacology; D015151:Immunoblotting; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011070:Poly I-C / Q000494:pharmacology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D015398:Signal Transduction; D015854:Up-Regulation; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
D015703:Antigens, CD; D015815:Cell Adhesion Molecules; D002867:Chromones; D019040:E-Selectin; D004791:Enzyme Inhibitors; D051550:I-kappa B Kinase; D018799:Intercellular Adhesion Molecule-1; D009025:Morpholines; D016328:NF-kappa B; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011070:Poly I-C; D051057:Proto-Oncogene Proteins c-akt; D019010:Vascular Cell Adhesion Molecule-1; C065289:ICAM2 protein, human; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one