Oral inoculation of Fusobacterium nucleatum exacerbates ulcerative colitis via the secretion of virulence adhesin FadA

The present study aimed to investigate the role of FadA adhesin in the colonization and invasion of F. nucleatum to epithelial cells using dextran sulfate sodium-induced colitis mice and molecular techniques. Oral inoculation of F. nulceatum strains harbored FadA adhesin further facilitated DSS mice in alveolar bone loss, disease severity, and mortality instead of FadA-deficient strains. In addition, CDH1 knockout mice manifested increased body weight, alveolar bone density, and alleviative disease severity in contrast with C57BL/6 mice. Moreover, FadA adhesin adheres to receptor E-cadherin and leads to phosphorylate of β-catenin and IκBα, regulating the NF-κB signaling pathway and up-regulating cytokines.