Porcine parvovirus induces apopyosis by activating TLR2-mediated NF-κB signaling pathway in PK-15 cells

Porcine parvovirus (PPV) mainly induces severe reproductive failure in pregnant swine, and causes huge economic losses to the swine industry. Cell apoptosis induced by PPV infection has been identified the major cause of reproductive failure. However, the molecular mechanism was not fully elucidated. In this study, the potential mechanism of PPV induced apoptosis in PK-15 cells was investigated. Our results showed that PPV induced apoptosis in PK-15 cells. Further studies revealed that PPV induces apoptosis by activating the nuclear factor-kappa B (NF-κB) signaling. The activation of NF-κB signaling was demonstrated by the phosphorylation of p65, p65 nuclear translocation and degradation of inhibitor of kappa B α (IκBα). Finally, our studies provided evidence that toll-like receptor 2 (TLR2) was involved in the PPV-mediated apoptosis and activation of NF-κB signaling. The expression of TLR2 were increased after PPV infection. TLR2 siRNA significantly decreased the apoptosis and activation of NF-κB after PPV infection. Together, these results provided evidence that the recognition between PPV and PK-15 cells was mainly through TLR2, and then induction of the NF-κB signaling pathway activation, which further induces apoptosis. Our study could provide information to understand the molecular mechanisms of PPV infection.