Intrinsic, extrinsic and endoplasmic reticulum stress-induced apoptosis in RK13 cells infected with equine arteritis virus.

The modulation of the expression of caspases by viruses influences the cell survival of different cell types. Equine arteritis virus (EAV) induces apoptosis of BHK21 and Vero cell lines, but it is not known whether EAV induces apoptosis in RK13 cells, a common cell line routinely used in EAV diagnosis and research. In this study, we determined that caspase-3 expression was triggered after infection of RK13 cells with EAV in a time- and dose-dependent manner. We also detected caspase-8 and caspase-9 activation, indicating the stimulation of both extrinsic and intrinsic apoptosis pathways. Finally, we found caspase-12 activation, an indicator of endoplasmic reticulum stress-induced apoptosis. The variability observed in the apoptotic response in the different cell lines demonstrates that apoptosis depends on the distinctive sensitivity of each cell line used for investigation.

Equine arteritis virus gP5 protein induces apoptosis in cultured insect cells.

Equine Arteritis Virus (EAV) has been shown to induce apoptosis in vitro but the induction of this mechanism has not been previously associated with any viral gene product. In this work, we found a cytotoxicity effect of the EAV gP5 protein on baculovirus-insect cells and a low yield of protein recovery. Besides, different morphological features by electron transmission microscopy, DNA fragmentation in agarose gel, TUNEL analysis and caspase 3 activity were found. All these findings indicate that the EAV gP5 protein induces apoptosis in insect cells.