It has been reported that in atherosclerosis, 7a-Hydroxycholesterol can elicit TLR6-mediated expression of IL-23 by monocytic cells via PI3K/Akt and MAPKs pathways (55), leading to inflammation via the upregulation of CCL2 and MMP-9 in macrophages (56). Here, MMP9 is linked to atherosclerosis.