cAMP-dependent activation of protein kinase A attenuates respiratory syncytial virus-induced human airway epithelial barrier disruption
Confluent airway epithelial cell monolayers were infected with RSV (MOI, 0.5) for 48 h. Forskolin (20 μM) was added to the cells either at the onset of viral infection (0 h) or at different times after RSV administration. (A) Cells were fixed and immunolabeled for different TJ and AJ proteins. Note that forskolin attenuated RSV-induced TJ and AJ disruption, even when added after the beginning of the infection (arrows). Scale bar, 40 μm. (B) The effect of forskolin on the permeability of control and RSV-infected cell monolayers was determined by measuring transepithelial dextran flux at 48 h of RSV infection. (C) mRNA expression of RSV F protein in epithelial cell lysates was quantified by RT-PCR at 48 h after RSV administration. For all assays, data is presented as mean ± SEM (n = 3). ***, P<0.001. Each image is representative of at least 3 independent experiments.