Miao et al. found that indole-3-aldehyde (IAld) significantly ameliorated renal fibrosis in CKD by inhibiting the AHR signaling pathway, as evidenced by the fact that IAld downregulates the expression of its downstream target genes (e.g., CYP1A1, CYP1B1) by reducing the nuclear translocation of the AHR, and thus inhibiting the production of pro-fibrotic proteins (e.g., α-SMA, collagen I) (Miao et al., 2024a). The gene discussed is CYP1B1; the disease is renal fibrosis.