Expression of AQP3 protein in hAECs is regulated by Camp-PKA-CREB signalling pathway.

Previous studies by others and our group have demonstrated the expression of AQP3 protein in human chorioamniotic membranes. Here, we investigated whether cyclic adenosine monophosphate (cAMP) up-regulation of aquaporin 3 (AQP3) protein expression in human amniotic epithelial cells (hAECs) is mediated by protein kinase A (PKA) dependent or independent pathway. Cells were treated with various concentrations of Forskolin, SP-cAMP, H-89 at various time intervals or optimal concentration of Forskolin in combination with H-89 in the blocking experiments. Forskolin significantly increased cAMP levels and the expression of PKA, p-CREB and AQP3. SP-cAMP had similar effects. H-89 inhibited PKA, p-CREB and AQP3 protein expression, and attenuated the stimulatory effect of Forskolin. These results show that the AQP3 protein expression in hAECs was regulated by cAMP-PKA-CREB signal pathway. A relatively short biological half life of AQP3 renders its rapid responsiveness to regulation.