LXRα is regulated by miR-155. A, miR-155 binds to human LXRα. HEK293 were transfected with either empty vector (pmiRGLO-MS2BD) or miR-155 sponge (pmiRGLO-MS2BD-miR155Sp) or 3′UTR-LXRα (pmiRGLO-MS2BD-LXRα WT), or MS2 mutated in MRE 3′UTR-LXRα (pmiRGLO-MS2BD-Lxrα-MT), and miR-155 captured in the immunoprecipitate quantified by quantitative PCR. Data presented as mean ± SEM of 2 technical replicates; representative of 3 experiments. B, miR-155−/− fibroblasts show downregulation of LXRα protein after transfection with miR-155 mimic. C, Time course of Lxrα mRNA expression in lungs of WT mice after bleomycin (n = 4-7 per group). D, Lung fibroblast gating strategy. Representative histograms (E) and quantitative evaluation (F) of an increase in LXRα expression in lung fibroblasts during fibrosis. Expression of Lxrα(G) and Abca1(H) in lungs of WT and miR-155−/− mice on day 18. I, Constitutive expression of Abca1 in lung fibroblasts (n = 4) and in alveolar macrophages (n = 4). Constitutive expression of Arg2 in alveolar macrophages (n = 5) (J) and after transfection with Lxrα siRNA (K) or treatment with 22(S)HC (30 μM) (L). Data presented as mean ± SEM or median and interquartile range. bleo, Bleomycin; MRE, microRNA recognition element; DMSO, dimethyl sulfoxide; MS2BD, MS2-binding domain. *P < .05.