Is host heparanase required for the rapid spread of heparan sulfate binding viruses?

Vaccinia virus (VACV), like many other viruses, binds to cell surface heparan sulfate (HS) prior to infecting cells. Since HS is ubiquitously expressed extracellularly, it seemed likely that VACV-HS interaction may impede virus spread, with host heparanase, the only known mammalian endoglycosidase that can degrade HS, potentially overcoming this problem. In support of this hypothesis, we found that, compared to wild type, mice deficient in heparanase showed a 1–3 days delay in the spread of VACV to distant organs, such as ovaries, following intranasal inoculation, or to ovaries and spleen following intramuscular inoculation. These delays in spread occurred despite heparanase deficiency having no effect on VACV replication at inoculation sites. Subsequent in vitro studies revealed that heparanase treatment released VACV from HS expressing, but not HS deficient, infected cell monolayers. Collectively these data suggest that VACV relies on host heparanase to degrade HS in order to spread to distant sites. • Poxviruses, like several other viruses, use cell surface heparan sulfate (HS) as a co-receptor during infection. • Heparanase is the only known mammalian endoglycosidase that can degrade HS. • Spread of HS binding viruses like vaccinia virus (VACV), is aided by host derived heparanase. • Heparanase treatment releases VACV from HS expressing, but not HS deficient, cell monolayers infected with VACV. • Targetting heparanase could be a novel approach to controlling HS-dependent viral infection. [ABSTRACT FROM AUTHOR]