Recent studies showed that Fusobacterium nucleatum (an oral and intestinal pathogenic bacterium) damaged intestinal epithelial integrity and increased intestinal epithelial permeability through regulating the distribution and expression of TJs proteins ZO-1 and occludin, and increasing the secretion of inflammatory cytokines (TNF-α, INF-γ, and IL-1β) which increased intestinal inflammation and exacerbated colitis [68]. Here, OCLN is linked to inflammatory response.