CNR1 and idiopathic pulmonary fibrosis: In addition to AEA, the other major endocannabinoid, 2-AG, was also reported to increase in various inflammatory and fibrotic conditions in skin (15), kidney (40), liver (13), and heart (41, 42), along with the overactivity of CB1R. Although we did not observe increased levels of 2-AG in the BALF of patients with IPF or HPSPF (2, 3), 2-AG levels were increased in the lungs and BALF of mice with bleomycin-induced PF (Supplemental Figure 3, E and F).