The HN protein of Newcastle disease virus induces cell apoptosis through the induction of lysosomal membrane permeabilization
Fig 3
LMP promotes NDV-induced apoptosis through the involvement of CTSB and CTSD.
(A) Schematic diagram of the experimental design for (B-G). HeLa cells or DF-1 cells were infected with Herts/33 at 0.01 MOI for 24h. Then, the cells were treated with Ca-074 (20 μM), Pep A (20 μM), DMSO, or mock-treated for 6h. (B&C&E&F) The apoptosis level of HeLa cells (B) or DF-1 cells (E) was measured by AnnexinV-FITC/PI staining using flow cytometry, and quantitation of the apoptosis rate of HeLa cells (C) and DF-1 cells (F) are shown, respectively. (D&G) The NP protein in HeLa cells (D) or DF-1 cells (G) was detected by Western blotting. (H) Schematic diagram of the experimental design for (I-M). HeLa cells were transfected with si-CTSB, si-CTSD, si-NC, or mock-transfected for 48h. Then, the cells were infected with Herts/33 at 0.01 MOI or mock-infected for 12h. (I-M) The indicated proteins were detected by Western blotting (I). The relative intensity of cleaved caspase 3 (J), cleaved caspase 7 (K), cleaved caspase 9 (L), and cleaved PARP1 (M) in NDV-infected cells were quantified by ImageJ software. GAPDH was used as a normalized control. All error bars represent SDs for triplicate analyses of three independent experiments. All significance analyses were assessed using one-way ANOVA with Dunnett’s multiple comparisons test.