Figure 5.

Innate Immunity Protected HLCs from Massive Apoptosis Induced by DENV

(A) DENV2 infection led to apoptosis of HLCs. At 48 hr post DENV infection at an MOI of 2, HLCs were fixed for TUNEL assay. For the positive control, 0.5 μM doxorubicin, as an apoptosis inducer, was incubated with HLCs for 24 hr. Scale bar, 50 μm.

(B) DENV2 infection resulted in PARP and CASP3 cleavage. HLCs at day 15 were pretreated with JAKi (1 μM) or Z-Vad (50 μM) for 3 hr, followed by DENV2 infection as described above.

(C) Most of the DENV2-infected cells survived the infection. Day-15 HLCs were incubated with or without JAKi (1 μM) for 3 hr, then subjected to DENV2 infection at an MOI of 5 for 144 hr. Cell samples were collected at different time points after infection for immunostaining. Scale bar, 50 μm.

(D) The time course of apoptosis induced by DENV2. HLCs treated with or without IFN-α2a (1,000 U/mL) or JAKi (1 μM) were incubated with or without DENV2 at an MOI of 5 for 144 hr as described above. Cell samples were collected every 24 hr and subjected to MTT assay. Relative cell viability was calculated by comparing each sample with the mock.

(E) PARP and CASP3 cleavage during DENV2 infection. HLCs were infected by DENV2 at an MOI of 5 for 144 hr. Cell samples at different time points were collected for western blotting.

(F) Comparison of cell death between HLCs and Huh 7.5 cells after DENV2 infection. Both HLCs and Huh 7.5 cells were infected by DENV2 at an MOI of 5 for 96 hr. Cell samples were collected every 24 hr for MTT assay.

Three independent experiments were performed. Data are presented as mean ± SD. p Values were calculated by Student's t test: ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001. See also Figure S4.