Fig. 6: ATF4 promotes the transcription of fibrotic genes via enhancer-dependent mechanisms.

a The snapshots of normalized ATF4 and H3K27ac and input ChIP-seq tracks at COL1A1 and LOXL2 loci across different conditions: Ctrl, TGFβ, and Tg treatment. The super-enhancers with ATF4 binding sites were highlighted in gray rectangles. The black arrows indicate the binding loci of ATF4, which were adopted for the ChIP-qPCR test. b ChIP-qPCR analysis showing the recruitment of ATF4 in the corresponding regions of COL1A1 and LOXL2 in the presence of solvent control, TGFβ, or combined TGFβ and JQ1 (n = 3 biological replicates). c A luciferase reporter containing a genomic region upstream of the COL1A1 gene (–9108 to –8708) was constructed to measure the transcriptional activity of the ATF4- and H3K27ac- co-bound regions. The COL1A1 reporter, along with a Renilla luciferase reporter, was transfected into LX-2 cells transduced with a control vector (Vec) or an ATF4-overexpression construct (ATF4-OE). The transfected cells were treated with solvent control, TGFβ (1 ng/ml) for 2 days, JQ1 (250 nM) for 12 h, or a combination of TGFβ (1 ng/ml) for 2 days and JQ1 (250 nM) for 12 h before they were analyzed by the Dual-Luciferase assay (n = 4 biological replicates). d qPCR analysis showing the expression of COL1A1 and LOXL2 in control or LX-2 cells overexpressing ATF4 treated with solvent control, TGFβ, JQ1, or a combination of TGFβ and JQ1 (n = 4 biological replicates). Data are presented as mean ± s.e.m and representative of at least three independent experiments. Unpaired, two-tailed Student’s t tests were applied for (b–d). Source data are provided as a Source Data file.