The role of sphingosine-1-phosphate signaling in HSV-1-infected human umbilical vein endothelial cells.

Infections with the herpes simplex virus type 1 (HSV-1) are common and widespread. Most infections remain undetected but severe forms may develop in newborns and in immunocompromised patients. Moreover, HSV-1 might be involved in the pathogenesis of atherosclerosis, which may include viral infection of the endothelium. Antiviral therapy is efficient to treat symptomatic patients. However, an increasing accumulation of resistance-associated mutations has been observed in the viral genome. Thus, new antiviral strategies are focused on host factors. Among others, signaling of bioactive sphingolipids seems to be important in mediating HSV-1 replication. With the present study, regulation and function of sphingosine-1-phosphate (S1P)-based signaling were analyzed in HSV-1-infected human umbilical vein endothelial cells (HUVEC). Our data indicate that viral replication in endothelial cells relies on sphingosine kinase (SK) activity and S1P receptor (S1PR) signaling, which involves the activation of phosphatidylinositol-3-kinase (PI3K) and the small GTPase Ras-related C3 botulinum toxin substrate 1 (Rac-1). Inhibitor- or siRNA-meditated reduction of Rac-1 activity decreased HSV-1 replication. In general, targeting S1P-related signaling may be a successful strategy to establish new anti-HSV-1 therapies.