Starting from the evidence showing that A3AR has an anti-inflammatory effect in pulmonary fibrosis and that the highly selective A3AR agonist MRS5980 is extremely effective in chronic neuropathic pain, we evaluated the ability of MRS5980 to control lung inflammation and fibrosis in an established mouse model of bleomycin-induced pulmonary fibrosis. The gene discussed is ADORA3; the disease is fibrosis.