Overexpressed FOXO3 improves inflammatory status in mice by affecting NLRP3-mediated cell coronation in necrotizing colitis mice.

Objective: To investigate the relationship between FOXO3 overexpression and NLRP3 and explore the effect of FOXO3 on necrotizing colitis. Methods: 100 clean grade newborn SD (Sprague Dawley) rats were randomly divided into 4 groups: NEC group, NEC + FOXO3a group, NEC + NC group and control group. NEC rat model was established by hypoxia + hypothermia stimulation; HE staining was used for detection of the inflammation of intestinal tissue. The histological scores of intestinal tissues were histologically scored, generally, there were three types of inflammatory scoring systems including anatomically based systems, severity-based systems and quality of life systems (Lim et al., 2015) and in this study we utilized severity-based systems by HE staining. Human intestinal epithelial cell line was transfected with recombinant plasmid overexpressing FOXO3a and recombinant plasmid overexpressing NLRP3, and divided into control group, LPS group, LPS + NC group, LPS + FOXO3a group and LPS + FOXO3a + NLRP3 group; Caspase-1 was used for the detection of pyroptosis. The expressions of FOXO3a, NLRP3, cleaved Caspase-1 and the expression of TLR4 in TLR4 signaling pathway were detected by RT-qPCR and WB. IL-1 beta, IL-6, IL-18 and TNF-alpha were detected by ELISA. Results: (1) FOXO3a is under-expressed and NLRP3 is highly expressed in NEC neonatal rat intestinal tissue. (2) The inflammatory condition of intestinal tissue in NEC + FOXO3a group was improved compared with NEC group (P<0.05). (3) FOXO3a was highly expressed in NEC + FOXO3a group. The expression of IL-1 beta, IL-6, IL-18, SOD and MDA in NEC + FOXO3a group was lower than that in NEC group. (4) The expression of IL-1 beta, IL-6, IL-18, SOD and MDA in intestinal epithelial cells of LPS + FOXO3a group was lower than other groups. (5) Overexpression of FOXO3a inhibits LPS-induced pyroptotic cell death in intestinal epithelial cells by inhibiting NLRP3. Conclusion: Overexpression of FOXO3 in mice with necrotizing colitis can improve inflammatory conditions in mice by affecting NLRP3-mediated cell caking.