MiR-223 promotes pyroptosis of enteritis cells through activating NF-κB signalling pathway by targeting SNIP1 in inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a common inflammation-related intestinal disease. Studies have shown that excessive pyroptosis of intestinal cells is involved in the development of IBD. However, the regulatory mechanism of pyroptosis in IBD remains unclear. Here, our study purposed to clarify the underlying regulatory mechanism of miR-223 to promote pyroptosis in IBD.MiR-223 and Smad Nuclear Interacting Protein 1 (SNIP1) expression in colon tissues collected from IBD patients and healthy volunteers were evaluated using qRT-PCR. Cell viability and pyroptosis were evaluated by CCK8 and flow cytometry assay, respectively. Pyroptosis-related proteins and nuclear factor κB (NF-κB) signals were determined by WB. Dual-luciferase reporter gene assay was employed to investigate the binding relationship between miR-223 and SNIP1.MiR-223 was significantly upregulated in IBD colon tissues and cell models, while SNIP1 was significantly decreased. Silence of miR-223 markedly enhanced cell viability and inhibited pyroptosis in the IBD cell model. MiR-223 could bind to 3'-UTR of SNIP1 and SNIP1 could activate NF-κB signalling pathway. Further rescued experiment found that knockdown of SNIP1 dramatically abolished the bio-effects mediated by miR-223 silence on the cell viability and pyroptosis of the IBD cell model. Likewise, the inactivation of NF-κB signalling markedly weakened the regulatory roles of SNIP1 downregulation in the IBD cell model. Besides, inhibition of NF-κB signalling attenuated the pyroptosis-promoting effect of overexpressing miR-223.Our data suggested that miR-223 activated the NF-κB pathway via targeting SNIP1, thus promoting the process of cell pyroptosis, and ultimately participating in the pathogenesis of IBD.

[Intervention mechanism of electroacupuncture in rats with ulcerative colitis: an analysis based on the Toll-like receptor 4/myeloid differentiation factor 88/nuclear factor-kappa B signaling pathway].

OBJECTIVE: To investigate the protective effect of electroacupuncture(EA) on rats with ulcerative colitis (UC) and its effect on the Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor-kappa B (NF-κB) signaling pathway. METHODS: Sprague-Dawley rats were randomly divided into blank group, model group, salicylazosulfapyridine (SASP) group, low-intensity EA group, and high-intensity EA group, with 8 rats in each group. Enema with 2，4，6-trinitrobenzenesulfonic acid was performed to establish a model of UC. The rats in the two EA groups were given EA at"Tianshu" (ST25), "Guanyuan" (CV4), and "Zusanli"(ST36) for 15 min each time, once a day, with a current intensity of 1 mA for the low-intensity EA group and 5 mA for the high-intensity EA group(among them, "Tianshu" "Zusanli" bilateral alternate acupoints); the rats in the SASP group were given SASP suspension 3 mL every day by gavage. The course of treatment was 15 days for all groups. HE staining was used to observe the pathology of the colon and determine tissue damage index(TDI); ELISA was used to measure the serum levels of interleukin-4 (IL-4), interleukin-10 (IL-10), interleukin-17 (IL-17), and prostaglandin E2 (PGE2); immunohistochemical staining and real-time PCR were used to measure the protein and mRNA expression of TLR4, MyD88, and NF-κB in colonic tissue. RESULTS: Compared with the blank group, the model group had significant reductions in body weight, serum IL-4, and IL-10 (P<0.05) and significant increases in colonic mucosa TID, the serum levels of IL-17 and PGE2 and the protein and mRNA expression of TLR4, MyD88, and NF-κB in colonic tissue (P<0.05). Compared with the model group, the SASP group and the EA groups had significantly higher body weight and serum levels of IL-4 and IL-10 (P<0.05), as well as significantly lower colonic TDI, serum levels of IL-17 and PGE2, and integrated optical density and mRNA expression of TLR4, MyD88, and NF-κB in colonic tissue (P<0.05). Compared with the SASP group, the low-intensity EA group had significantly higher colonic TDI and protein and mRNA expression of TLR4, MyD88, and NF-κB in colonic tissue (P<0.05), and compared with the SASP group, the high-intensity EA group had a significantly higher body weight (P<0.05) and lower colonic TDI and protein and mRNA expression of TLR4, MyD88, and NF-κB in colonic tissue (P<0.05). Compared with the low-intensity EA group, the high-intensity EA group had significantly higher body weight (P<0.05), and lower colonic TDI and protein and mRNA expression of TLR4, MyD88, and NF-kB in colonic tissue (P<0.05). CONCLUSION: Electroacupuncture exerts a protective effect on the colonic mucosa in rats with UC possibly by inhibiting the TLR4/MyD88/NF-κB signaling pathway and reducing the release of inflammatory cytokines, and high-intensity EA may have a better effect than low-intensity EA.