Adenylyl cyclase 6 overexpression decreases the permeability of endothelial monolayers via preferential enhancement of prostacyclin receptor function.

Overexpression of adenylyl cyclase (AC) has been proposed as a potential gene therapy strategy to increase cAMP formation in cardiomyocytes and cardiac function in vivo. The impact of AC overexpression on endothelial cells, which will be traversed by genes delivered in vivo, has not been examined. Hence, the goal of the current study was to determine the consequence of AC overexpression on vascular endothelial cells in terms of G-protein-coupled receptor (GPCR) signaling and endothelial barrier function. We demonstrate that adenoviral-mediated gene transfer of AC6 in human umbilical vein endothelial cells preferentially enhances prostacyclin receptor (versus other GPCR)-stimulated cAMP synthesis and, in parallel, inhibits thrombin-stimulated increases in endothelial cell barrier function. Using multiple strategies, including prostacyclin receptor-targeted small interfering RNA, we identify that the enhancement of endothelial barrier function by AC6 overexpression is dependent on an autocrine/paracrine feedback pathway involving the release of prostacyclin and activation of prostacyclin receptors. AC6 overexpression in endothelial cells may have use as a means to enhance prostacyclin function and reduce endothelial barrier permeability.