Fig. 3.

H1N1 replication is impaired by knocking down HIF-1 pathway. A Cell viability of shcontrol and shHIF-1α A549 cells was measured by a CCK-8 assay. B, C shcontrol and shHIF-1α A549 cells were infected with H1N1 at an MOI of 1, and cells and supernatants were harvested at 24 h p.i.. HIF-1α mRNA level was measured by qRT-PCR (B). Lactate in cell supernatant was measured by a lactate assay kit (C). D–F shcontrol and shHIF-1α A549 cells were mock infected or infected with H1N1 at an MOI of 1, and cells and supernatant were harvested at 24 h p.i.. The expression of HIF-1α and NP was analyzed by western blotting (D). Intracellular viral RNA (M gene) in infected groups was measured by qRT-PCR (E), β-actin expression was used as an internal control. Virus titer in cell supernatant in infected groups was measured by plaque forming unit assay (F). G Cell viability of shcontrol and shHIF-1β A549 cells was measured by a CCK-8 assay. H shcontrol and shHIF-1β A549 cells were mock infected or infected with H1N1 at an MOI of 1, and cells were harvested at 24 h p.i.. The expression of HIF-1β and NP was analyzed by western blotting. ns, not significant. **P < 0.01, ***P < 0.001.