As determined by RT-qPCR, PAH showed dose-dependent inhibition on the Ifnb/IFNB expression with cellular IC50 of 151.6 ± 8.9 μM for L929, 40.3 ± 2.93 μM for MEF, and 55.79 ± 3.25 μM for HFF cells (Figure 2D). This evidence concerns the gene IFNB1 and pulmonary arterial hypertension.