Epizootic haemorrhagic disease virus induced apoptosis in bovine carotid artery endothelium is p53 independent.

Abstract

Epizootic haemorrhagic disease virus (EHDV) replicates in endothelium and it has been shown that EHDV serotype 2 (Ibaraki) is able to cause cell death by apoptosis in cow pulmonary artery endothelial cells. However, the underlying mechanism has not been established. For some viruses, such as influenza, a p53 dependent mechanism has been demonstrated in viral induced apoptosis. In this study, we investigate the involvement of p53 in the induction of apoptosis in a US isolate of EHDV serotype 2 in cow endothelium. We inoculated cow carotid artery endothelial cell cultures with live and inactivated EHDV‑2 isolated from a white‑tailed deer (Odocoileus virginianus). Using in situ nick end‑labeling (TUNEL), caspase‑3 (cleaved) immunohistochemistry (IHC), flow cytometry and annexin staining we documented the development of apoptosis and its direct relation to viral replication. p53 gene regulation and protein expression were assessed by reverse transcription polymerase chain reaction and IHC, respectively, in infected cells. We show that p53 mRNA was not upregulated and protein expression was not significantly increased. No increase of p53 mRNA or protein expression was observed in cells that stained positive for EHDV antigen. Our results indicate that EHDV induces apoptosis through a p53 independent mechanism.