MMP9 and pulmonary arterial hypertension: Moreover, both phosphorylation of signal transducer and activator of transcription 3 (STAT3, as the vital downstream signal of IL-6) and matrix metalloproteinase-9 (MMP9, as a critical mediator for migration) were suppressed by DMY in MCT induced PAH of rats and IL-6 stimulated HPASMCs (Li et al., 2017).