Figure 1. Carvedilol-mediated in vivo activation of miR-466g, miR-532-5p and miR-674 requires β-arrestin1 or β-arrestin2 and GRK5 or GRK6. Moreover, β₁-adrenergic receptor is required for Carv-mediated post-transcriptional activation of miR-674, while β₂-adrenergic receptor is required for Carv-mediated post-transcriptional activation of miR-466g or miR-532-5p.

A–C, WT, β-arrestin1 knockout (KO), β-arrestin2 KO, GRK5 KO, GRK6 KO, β₁AR KO, β₂AR KO or β₁AR/β₂AR double KO (DKO) mice were infused with DMSO (vehicle control) or Carv (19mg/Kg/day) for 7 days by using micro-osmotic pumps. QRT-PCR experiments were performed on RNAs isolated from mouse hearts. Three mature miRs were elevated upon Carv stimulation in WT mice. However, this induction was completely abolished in β-arrestin1 KO, β-arrestin2 KO, GRK5 KO or GRK6 KO mice, indicating an essential role of either β-arrestin and either GRK in the synthesis of mature miRs. Moreover, Carv-mediated activation of miR-466g and miR-532-5p, which is seen in WT and β₁AR KO mice, was abolished in β₂ AR KO and β₁AR/β₂AR DKO mice (A–B). Carv-mediated activation of miR-674, which is seen in WT and β₂AR KO mice, was abolished in β₁AR KO and β₁AR/β₂AR DKO mice (C). Data are shown as mean ± SEM for n=6 independent mice per group. The relative fold induction of Carv is calculated by normalizing DMSO controls for each genotype, which is indicated by vertical lines. *P<0.05 or **P<0.01 vs. DMSO. D–E, WT mice were infused with DMSO or Carv as above. QRT-PCR experiments were performed on RNAs from mouse hearts. The three pri- (D) or pre- (E) miRs were not changed significantly upon Carv stimulation in WT mice. NS: not significant. Data are shown as mean ± SEM for n=8 independent mice per group.