ABSTRACT
BACKGROUND: Sodium butyrate (NaB) is a short-chain fatty acid produced by intestinal microbial fermentation of dietary fiber, and has been shown to be effective in inhibiting ulcerative colitis (UC). However, how NaB regulates inflammation and oxidative stress in the pathogenesis of UC is not clear. AIMS: The purpose of this study was to use a dextran sulfate sodium salt (DSS)-induced murine colitis model, and determine the effects of NaB and the related molecular mechanisms. METHODS: Colitis model was induced in mice by administration of 2.5%(wt/vol) DSS. 0.1 M NaB in drinking water, or intraperitoneal injection of NaB (1 g/kg body weight) was given during the study period. In vivo imaging was performed to detect abdominal reactive oxygen species (ROS). Western blotting and RT-PCR were used to determine the levels of target signals. RESULTS: The results showed that NaB decreases the severity of colitis as determined by an improved survival rate, colon length, spleen weight, disease activity index (DAI), and histopathological changes. NaB reduced oxidative stress as determined by a reduction in abdominal ROS chemiluminescence signaling, inhibition of the accumulation of myeloperoxidase and malondialdehyde, and restoration of glutathione activity. NaB activated the COX-2/Nrf2/HO-1 pathway by increasing the expressions of COX-2, Nrf2, and HO-1 proteins. NaB inhibited the phosphorylation of NF-κB and activation of NLRP3 inflammasomes, and reduced the secretion of corresponding inflammatory factors. Furthermore, NaB promoted the occurrence of mitophagy via activating the expression of Pink1/Parkin. CONCLUSIONS: In conclusion, our results indicate that NaB improves colitis by inhibiting oxidative stress and NF-κB/NLRP3 activation, which may be via COX-2/Nrf2/HO-1 activation and mitophagy.
Subject(s)
Colitis, Ulcerative , Colitis , Mice , Animals , NF-kappa B/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Butyric Acid/pharmacology , Dextran Sulfate/toxicity , NF-E2-Related Factor 2/genetics , NF-E2-Related Factor 2/metabolism , Reactive Oxygen Species/metabolism , Mitophagy , Cyclooxygenase 2/metabolism , Colitis/chemically induced , Colitis/drug therapy , Colitis/pathology , Colitis, Ulcerative/pathology , Signal Transduction , Oxidative Stress , Sodium Chloride , Mice, Inbred C57BL , Disease Models, AnimalABSTRACT
Colorectal cancer (CRC) is one of the most common malignancies, and effective treatment and prevention methods are lacking. Sodium butyrate (NaB) is a short-chain fatty acid produced by intestinal microbial fermentation of dietary fiber. It has been shown to be effective in inhibiting CRC, but the mechanism is not known. METHODS: Human normal intestinal epithelial cell line FHT and colorectal tumor cell line HCT-116 were treated with NaB alone or in combination with different programmed cell death inhibitors. Cell activity was then assessed with MTT assays and PI staining; ferroptosis with Fe2+, glutathione (GSH), and lipid peroxidation assays; signaling pathway screening with PCR arrays; and CD44, SCL7A11, and GPX4 expression with Western blotting. A CD44-overexpressing HCT-116 cell line was constructed to determine the effect of the overexpression of CD44 on NaB-induced ferroptosis. The synergistic effect of co-treatment with NaB and Erastin was assessed by isobolographic analysis. RESULTS: NaB induced apoptosis and ferroptosis in HCT-116 cells but only induced low-level apoptosis in FHC cells. Moreover, NaB significantly increased intracellular Fe2+ and promoted GSH depletion and lipid peroxidation in HCT-116 cells. Ferroptosis-related qPCR array analysis identified CD44/SLC7A11 as a potential effector molecular of NaB-induced ferroptosis. NaB significantly inhibited the expression of CD44 and SLC7A11 in mouse CRC tissues. A CD44 overexpressed HCT-116 cell line was used to verify that CD44/SLC7A11 was a key signaling pathway that NaB-induced GSH depletion, lipid peroxidation accumulation, and ferroptosis in HCT-116 cells. Examination of whether NaB can increase the effect of ferroptosis agents showed that NaB, in combination with Erastin, a ferroptosis inducer, further promoted HCT-116 cell death and increased changes of ferroptosis markers. CONCLUSIONS: Our results suggest that NaB induces ferroptosis in CRC cells through the CD44/SLC7A11 signaling pathway and has synergistic effects with Erastin. These results may provide new insights into CRC prevention and the combined use of NaB and ferroptosis-inducing agents.
