Down-regulation of cellular protein heme oxygenase 1 inhibits proliferation of classical swine fever virus in PK-15 cells.

Heme oxygenase 1 (HO-1) is an inducible enzyme that exerts potent antioxidant and anti-inflammatory effects, which also plays a critical role in host defenses against microbial, and particularly viral, infections. In our previous study, up-regulation of HO-1 was observed in peripheral blood leukocytes (PBLs) by genomic expression profiling, following infection of pigs with virulent classical swine fever virus (CSFV), the causative agent of a highly contagious disease threatening global pig industry (Shi et al., 2009). To study the potential involvement of HO-1 in CSFV proliferation, the role of its down-regulation in CSFV-infected PK-15 cells was further investigated. Results showed that infection with virulent CSFV strain Shimen significantly up-regulated the expression of HO-1 and that its down-regulation by small interfering RNA (siRNA) could inhibit CSFV proliferation as measured by genomic replication and production of infectious virus. The study revealed the involvement of HO-1 in CSFV proliferation, indicating that HO-1 is a potential target for inhibition of CSFV replication.