LAUSR

ABSTRACT Circular RNA (circRNA) had been confirmed to participate in ulcerative colitis (UC) development. Circular RNA_0001187 (Circ_0001187) had been found to be overexpressed in patients with Crohn disease. Therefore, circ_0001187 might be an important circRNA regulating intestinal inflammatory diseases. However, the role and mechanism of circ_0001187 in UC progression remains unclear. The colonic mucosal tissues were obtained from 23 UC patients and 23 healthy normal controls. Tumor necrosis factor-α (TNF-α) was used to mimic UC cell model in vitro. Cell function was assessed by cell counting kit 8 assay, EdU assay, flow cytometry, ELISA assay and oxidative stress detection. RNA interaction was confirmed by dual-luciferase reporter assay and RIP assay. Serum exosomes were isolated by ultracentrifugation and identified by transmission electron microscope. Circ_0001187 was overexpressed in UC patients. Circ_0001187 knockdown enhanced the proliferation, while suppressed apoptosis, inflammation and oxidative stress of TNF-α-induced FHC cells. Circ_0001187 acted as miR-1236-3p sponge, and the effects of circ_0001187 downregulation on TNF-α-induced FHC cell injury were overturned by miR-1236-3p inhibitor. MYD88 was targeted by miR-1236-3p, and circ_0001187 sponged miR-1236-3p to regulate MYD88. MYD88 knockdown alleviated TNF-α-induced FHC cell injury, and its upregulation revoked the inhibition effect of miR-1236-3p on TNF-α-induced FHC cell injury. High expression of circ_0001187 also was observed in the serum exosomes of UC patients. Our data confirmed that circ_0001187 facilitated UC progression through miR-1236-3p/MYD88 axis, which might be a potential treatment and diagnosis biomarker for UC. Graphical abstract