Probiotics, such as Bacillus subtilis and Bifidobacterium longum, on the other hand, alleviate inflammation and repair barrier function by downregulating proinflammatory cytokines (e.g., IL-17, IL-23, and TNF-α) and upregulating TJ proteins (e.g., claudin-1, occluding, and ZO-1) in colitis mice models (36–38). The gene discussed is IL17A; the disease is colitis.