Host Enzymes Heparanase and Cathepsin L Promote Herpes Simplex Virus-2 Release from Cells

Herpes simplex virus-2 (HSV-2) can productively infect many different cell types of human and non-human origin. Here we demonstrate interconnected roles for two host enzymes, heparanase (HPSE) and cathepsin L in HSV-2 release from cells. In vaginal epithelial cells and other cell lines tested, HSV-2 causes heparan sulfate shedding and upregulation in HPSE levels during the productive phase of infection. We also noted increased levels of cathepsin L and show that regulation of HPSE by cathepsin L via cleavage of HPSE proenzyme is important for infection. Furthermore, inhibition of HPSE by a specific inhibitor, OGT 2115, dramatically reduces HSV-2 release from vaginal epithelial cells. Likewise, we show evidence that the inhibition of cathepsin L is detrimental to the infection. The HPSE increase after infection is mediated by an increased NF-kB nuclear localization and a resultant activation of HPSE transcription. Together these mechanisms contribute to the removal of heparan sulfate from the cell surface, and thus facilitate virus release from cells.