Identification of IPNV-induced ER stress signal can induce Bcl-2 family proteins downregulation and apoptotic cell death.

<p>Infection of IPNV in CHSE-214 cells following incubation for 0 h, 6 h, 9 h and 12 h p.i. (A) Bcl-2, Mcl-1 and Bcl-xL proteins expression levels were detected by Western blots, and the gels were immunoblotted with a polyclonal antibody to Bcl-2 and Bcl-xL, and with a monoclonal antibody to Mcl-1. Lanes 1–4: Cells infected with IPNV were incubated for 0 h (lane 1), 6 h (lane 2), 9 h (lane 3) and 12 h (lane 4). The HeLa cell lysate is a positive control as shown in lane 5. Internal control Actin for experiments whose results are depicted in panel A. (B–D) Quantification of Bcl-2, Mcl-1 and Bcl-xL proteins expression levels in IPNV-infected cells at early and middle replication stages. Protein expression level was quantified by Personal Densitometer (Molecular Dynamic). Data were analyzed using either paired or unpaired Student's t-tests, as appropriate. * <i>p</i><0.05 was taken as a statistically significant difference between group mean values. (E) Identification of IPNV induces apoptotic and post-apoptotic necrosis in CHSE-214 cells. Annexin V-labeled (fluorescing) apoptotic cells indicated by arrows at 12 h p.i. with IPNV infection. (Fig. 3E, panels c and d); without infection group as negative control (Fig. 3E, panels a and b) at 12 h p.i. (Bar = 10 µm.). (F) Annexin-V positive cells were counted per 200 cells and data was analyzed using either or unpaired Student <i>t</i>-tests as appropriate at 0 and 12 h p.i. A value of <i>p</i><0.02 was taken to represent a statistically significant difference between mean values of groups.