Cyclic guanosine monophosphate compartmentation in human vascular smooth muscle cells

Aims: The role of different vascular subtypes of phosphodiesterases (PDE) in cGMP compartmentalization was evaluated in human smooth muscle cells. Methods and results: To understand how the cGMP conveys different information we infected smooth muscle cells with adenovirus containing mutants of the rat olfactory cyclic nucleotide-gated (CNG) channel-subunit and we recorded the associated cGMP-gated current (I-CNG). The whole cell configuration of patch clamp technique was used to measure the I-CNG and also the potassium current (I-K) in human umbilical artery smooth muscle cells (HUASMC). ANP (0.1 mu M) induced a clear activation of basal I-CNG, whereas SNP (100 mu M) had a slight effect. The nonselective PDE inhibitor (IBMX; 100 mu M), the PDE5 inhibitor (T0-156; 1 mu M) and the PDE3 inhibitor (cilostamide; 10 mu M), all had a tiny effects on the basal I-CNG current. Concerning potassium channels, we observed that ANP and testosterone induced activation of IK and this activation is bigger than that elicited by SNP, cilostamide and T0-156. Cilostamide and T0-156 decreased the CNG stimulation induced by ANP and testosterone, suggesting that pGC pool is controlled by PDE3 and 5. Thus, the effects of SNP show the existence of two separated pools, one localized next to the plasma membrane and controlled by the PDE5 and PDE3, and a second pool localized in the cytosol of the cells that is regulated mainly by PDE3. Conclusions: Our results show the existence of cGMP compartmentalization in human vascular smooth muscle cells and this phenomenon can open new perspectives concerning the examination of PDE families as therapeutic targets. (C) 2015 Elsevier Inc. All rights reserved.