PDE4A and inflammatory bowel disease: In addition to ferroptosis and cell differentiation, further investigation was needed to explore the other function of VTN in IBD in the future, including intestinal mucosal immunity, drug resistance, and intestinal fibrosis, and whether VTN regulated the phosphorylation of PDE4 in an integrin-dependent manner could be confirmed in next work, although the studies have confirmed that intergern was activated by VTN stimulation [26, 47, 48].