The effect of phosphodiesterase (PDEs) 4C to regulation the activity of lysosomes

Phosphodiesterases (PDEs) are involved in many cellular signal transductions mediated by cAMP. The PDEs are involved in phosphorylation when the precursors of soluble lysosomal enzymes transport into the lysosomes. To certify the relation between lysosomal activity and PDEs, Bovine Aortic Endothelial cells (BAECs) were transfected with 200, 300 and 400 pmol antisenses of PDE4A, B, C and D, respectively. Through cytochemical analysis of lysosomes with LysoTracker, we demonstrated the number and fluorescent intensity of lysosomes in BAECs. The PDE4 series, cathepsin B and D were quantitatively analyzed by western blotting. We found that the lysosomes decreased only in the case of PDE4C knock-down, and was not affected by other PDE series. In addition, PDE4 series were decreased by antisense transfection, cathepsin B was reduced by transfection of PDE4C antisense, while cathepsin D was increased. Therefore, our results suggest that only PDE4C would affect the activity of cathepsin B and D in cells.