Fig. 4

The effect of miRNA-21 on viral replication and host cell apoptosis and proliferation. HeLa cells were transduced with Lenti-miRNA-21 at MOI = 10, followed by CVB3 infection at MOI = 1 at 3 days after transduction. Cells transduced with Lenti-miR-CON and sham-infected cells were used as controls. a Western blot assay was conducted to detect CVB3 capsid protein VP1 at 12 h post infection. Representative results from 3 independent experiments are shown. b Intracellular viral titers were detected at 12 h post CVB3 infection. c Cell lysates were harvested and caspase-3 activity was detected using a fluorogenic substrate at indicated time points. d Immunoblot analysis of whole-cell protein lysates from CVB3 infected cells probed with cleave-caspase 3 and Bax antibody. e CVB3 induces apoptosis was measured by Annexin-V binding to externalized phosphatidylserine, representative FACS data of annexin-V⁺ apoptotic cells were shown. Cell viability assay was performed at multiple time points, with different amounts of miRNA-21 without (f) or with CVB3 infection (g). The viability of HeLa cell was determined by MTS assay at indicated time points, (*p < 0.05)