STAT1 participates in the induction of substance P expression in airway epithelial cells by respiratory syncytial virus.

PURPOSE The regulation effect and mechanism of respiratory syncytial virus (RSV) infection on the expression of tachykinin substance P (SP) in airway epithelial cells was investigated. METHODS The regulation of SP expression by RSV was investigated in the BEAS-2B airway epithelial cell line. RT-qPCR, immunofluorescence, and ELISA assay were used to examine the expression of the SP encoding gene TAC1, the intracellular SP protein expression, and the extracellular SP secretion. RESULTS The mRNA expression of TAC1 and the intracellular SP protein level in BEAS-2B cells were significantly enhanced by RSV infection with multiplicity of infection (MOI) values of both 1 and 0.1 at 48 hours post infection. Heat-inactivated and UV-inactivated RSV, but not live RSV, significantly induced SP secretion in both control BEAS-2B cells and CX3CR1 receptor knockout cells without affecting the TAC1 gene expression or cell viability. RSV G protein (2-10 μg/ml) and fractalkine (10-50 ng/ml), both CX3CR1 receptor ligands, did not affect SP secretion in BEAS-2B cells. Inhibition of STAT1 phosphorylation by fludarabine (1 μM) markedly reduced the RSV-induced TAC1 gene expression and antagonized the inhibition of RSV replication by interferon-α in BEAS-2B cells. CONCLUSIONS STAT1 participates in RSV infection-induced SP expression in airway epithelial cells.