The underlying biochemical consequences of inflammatory bowel disease (IBD) on the systemic and gastrointestinal metabolism have not yet been fully elucidated but could help to better understand the disease pathogenesis and to identify tissue-specific markers associated with the different disease stages. Here, we applied a metabonomic approach to monitor metabolic events associated with the gradual development of Crohn's disease (CD)-like ileitis in the TNF(ΔARE/WT) mouse model. Metabolic profiles of different intestinal compartments from the age of 4 up to 24 weeks were generated by combining proton nuclear magnetic resonance ((1)H NMR) spectroscopy and liquid chromatography-mass spectrometry (LC-MS). From 8 weeks onward, mice developed CD similar to the immune and tissue-related phenotype of human CD with ileal involvement, including ileal histological abnormalities, reduced fat mass and body weight, as well as hallmarks of malabsorption with higher energy wasting. The metabonomic approach highlighted shifts in the intestinal lipid metabolism concomitant to the histological onset of inflammation. Moreover, the advanced disease status was characterized by a significantly altered metabolism of cholesterol, triglycerides, phospholipids, plasmalogens, and sphingomyelins in the inflamed tissue (ileum) and the adjacent intestinal parts (proximal colon). These results describe different biological processes associated with the disease onset, including modifications of the general cell membrane composition, alteration of energy homeostasis, and finally the generation of inflammatory lipid mediators. Taken together, this provides novel insights into IBD-related alterations of specific lipid-dependant processes during inflammatory states.
BackgroundInflammatory bowel diseases (IBD) are chronic intestinal inflammatory diseases affecting about 1% of western populations. New eating behaviors might contribute to the global emergence of IBD. Although the immunoregulatory effects of omega-3 fatty acids have been well characterized in vitro, their role in IBD is controversial.MethodsThe aim of this study was to assess the impact of increased fish oil intake on colonic gene expression, eicosanoid metabolism and development of colitis in a mouse model of IBD. Rag-2 deficient mice were fed fish oil (FO) enriched in omega-3 fatty acids i.e. EPA and DHA or control diet for 4 weeks before colitis induction by adoptive transfer of naïve T cells and maintained in the same diet for 4 additional weeks. Onset of colitis was monitored by colonoscopy and further confirmed by immunological examinations. Whole genome expression profiling was made and eicosanoids were measured by HPLC-MS/MS in colonic samples.ResultsA significant reduction of colonic proinflammatory eicosanoids in FO fed mice compared to control was observed. However, neither alteration of colonic gene expression signature nor reduction in IBD scores was observed under FO diet.ConclusionThus, increased intake of dietary FO did not prevent experimental colitis.
These results demonstrate the anti-inflammatory properties of LWB and suggest that the underlying mechanism is at least in part due to NF-κB inhibition and improved anti-oxidative capacity.
The hydroperoxide of linoleic acid (13-HPODE) degrades to 9,12-dioxo-10(E)-dodecenoic acid (DODE) which readily modifies proteins. This study identified the major proteins in MCF7 cells modified by DODE. To reduce false positives, three methods were use to identify DODEmodified proteins. First, cells were treated with a synthetically biotinylated 13-HPODE (13-HPODE-biotin). Modified proteins were enriched by neutravidin affinity and identified by 2D-LC-MS/MS. Second, cells were treated with native 13-HPODE. Protein-carbonyls were biotinylated with an aldehyde reactive probe (ARP) and modified proteins enriched by neutravidin affinity and identified by 2D-LC-MS/MS. Third, using a newly developed DODE antibody, DODE modified proteins were located by 2D-SDS-PAGE and Western blot and identified by ingel digestion and LC-MS/MS. Analysis of the proteins characterized by all three methods revealed a significant overlap and identified 32 primary proteins modified by DODE in MCF7 cells. These results demonstrated the feasibility for the cellular formation of DODE protein-carbonyl adducts that may be future indicators of oxidative stress.
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