The AHR ligands FICZ (Shi et al., 2020), kynurenine (Li et al., 2014) and dioxin (Tsai et al., 2014) promote MMP-1 in vitro. The AHR ligand indole-3-carbinol inhibits MMP-2 and MMP-9 in vitro (Wu et al., 2005) and in a murine model of liver fibrosis, the AHR ligand paquinimod reduced the expression of MMP-2 (Fransen Pettersson et al., 2018), highlighting the diversity of the AHR response in ECM maintenance. Here, MMP2 is linked to Hepatic fibrosis.