FOXO1 and intervertebral disk degenerative disorder: Our study identified some circRNA–miRNA–mRNA interaction axes, including circRNA_100086–miR-509-3p–MAPK1, circRNA_000200–miR-185-5p–TGFB1, circRNA_104308–miR-185-5p–TGFB1, circRNA_400090–miR-486-5p–FOXO1 and circRNA_400090–miR-486-5p–SMAD2, which may be associated with the progression of IDD and which may therefore serve as biomarkers of IDD.