FIG 4.

Inhibition of DRD4 activity inhibits DENV2 infection. (A) HEK293 cells were infected with DENV2 at an MOI of 0.1 FFU/cell in the presence of either DMSO, 10 μM 4F-4PP oxalate (a 5HTR2A antagonist), L741,742 dihydrochloride (a DRD4 antagonist), or SKI-417616. Additionally, samples were treated with DMSO or 10 μM dopamine, as indicated. Supernatants were collected at 48 h p.i., and titers were determined on Vero cells. ***, P < 0.001; **, P < 0.01. (B) HeLa cells were transfected with siRNAs targeting 5HTR2A or DRD4. At 48 h posttransfection, total RNA was isolated and was analyzed by RT-qPCR for 5HTR2A (left) or DRD4 (right) expression; results were normalized to β-actin levels. (C) siRNA-transfected HeLa cells were infected with DENV2 at an MOI of 5 FFU/cell and were fixed at 72 h p.i. Envelope protein was detected by immunofluorescence. (D) Integrated density was quantitated for three independent experiments using ImageJ software.