Lithium chloride restores host protein synthesis in herpes simplex virus-infected endothelial cells

In previous studies we have shown that herpes simplex virus type 1 (HSV-1) infection suppresses host-cell protein synthesis in human endothelial cells (EC). It has been demonstrated that lithium salts prevent viral replication in HSV-1 infected cells. In the present study, we have measured host-cell protein synthesis in HSV-1 infected EC in the presence or absence of 20 and 30 mM LiCl. Although LiCl restored synthesis of almost all host-cell proteins, [35S]methionine incorporation was most pronounced in thrombospondin and plasminogen activator inhibitor 1 and least in fibronectin and type IV collagen. LiCl was more effective at the higher concentration (30 mM) and when the compound was added to the EC culture at the time of infection rather than after adsorption of HSV-1. Synthesis of virus proteins continued in LiCl-treated EC but at a reduced rate. The data suggest that LiCl not only interferes with virus replication, but may also, to some extent, interfere with the virion-associated inhibition of host protein synthesis.