tranilast and Influenza--Human

Asthma and chronic obstructive pulmonary disease (COPD) exacerbations are commonly associated with respiratory syncytial virus (RSV), rhinovirus (RV) and influenza A virus (IAV) infection. The ensuing airway inflammation is resistant to the anti-inflammatory actions of glucocorticoids (GCs). Viral infection elicits transforming growth factor-β (TGF-β) activity, a growth factor we have previously shown to impair GC action in human airway epithelial cells through the activation of activin-like kinase 5 (ALK5), the type 1 receptor of TGF-β. In the current study, we examine the contribution of TGF-β activity to the GC-resistance caused by viral infection. We demonstrate that viral infection of human bronchial epithelial cells with RSV, RV or IAV impairs GC anti-inflammatory action. Poly(I:C), a synthetic analog of double-stranded RNA, also impairs GC activity. Both viral infection and poly(I:C) increase TGF-β expression and activity. Importantly, the GC impairment was attenuated by the selective ALK5 (TGFβRI) inhibitor, SB431542 and prevented by the therapeutic agent, tranilast, which reduced TGF-β activity associated with viral infection. This study shows for the first time that viral-induced glucocorticoid-insensitivity is partially mediated by activation of endogenous TGF-β.

Topics: Anti-Inflammatory Agents; Antiviral Agents; Asthma; Benzamides; Cell Line; Dioxoles; Drug Resistance, Viral; Enzyme Activation; Epithelial Cells; Glucocorticoids; Humans; Influenza A virus; Influenza, Human; ortho-Aminobenzoates; Picornaviridae Infections; Poly I-C; Protein Serine-Threonine Kinases; Pulmonary Disease, Chronic Obstructive; Receptor, Transforming Growth Factor-beta Type I; Receptors, Transforming Growth Factor beta; Respiratory Mucosa; Respiratory Syncytial Virus Infections; Respiratory Syncytial Viruses; Rhinovirus; Transforming Growth Factor beta