Antagonists of macrophage migration inhibitory factor (MIF), such as MIF098 and ISO-1, inhibit pulmonary artery smooth muscle cell proliferation and collagen deposition by modulating MAPK/ERK and TGF-β1/Smad signaling, improving cardiopulmonary pathology in systemic lupus erythematosus– and idiopathic pulmonary fibrosis–associated PAH models (157, 158). The gene discussed is MIF; the disease is pulmonary fibrosis.