TJP1 and colitis: 132,133E. coli Nissle 1917 (EcN), for instance, has been observed to increase ZO-1 expression in healthy and DSS-induced colitis mouse models (Figure 4(c)).132 While the precise mechanism by which EcN controls ZO-1 expression remains unclear, it is known that ZO-1 plays a crucial role in the formation of tight junctions, thereby maintaining intestinal barrier integrity.134