CLDN5 and lymphocytic colitis: Watari et al. (2016) showed that increased expression of CLDN5 by checkpoint kinase 1 (Chk1) activation enhances intestinal epithelial function in Caco-2 cells. Additionally, it has been shown in Campylobacter jejuni-infected IL10 knockout mice and in an in vitro model that resveratrol reduced leaky gut syndrome by upregulating CLDN5 expression (Lobo de Sa et al., 2021). Barmeyer et al. (2017) showed that epithelial barrier dysfunction and leaky gut in lymphocytic colitis occur through downregulation and redistribution of CLDN5.