Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.108 (lactase)
 2,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using metabolic labeling techniques in human intestinal epithelial cell lines in tissue culture and in situ hybridization techniques in normal and inflamed (Crohn's) intestine, recent studies have shown that there is synthesis of acute phase proteins in enterocytes. Moreover, these studies have shown that acute phase protein biosynthesis in enterocytes is regulated by inflammatory cytokines in a manner characteristic of the physiologic acute phase response. In the course of these studies it was noticed that one inflammatory cytokine, interleukin-6 (IL-6), mediated selective down-regulation of the enterocyte-specific, differentiation-dependent integral membrane protein sucrase-isomaltase (SI) in the Caco2 intestinal epithelial cell line. In the current study we examined the effect of several other inflammatory cytokines interleukin-1 (IL-1 beta), tumor necrosis factor alpha (TNF alpha), and interferon gamma (IFN gamma) on synthesis of SI in Caco2 cells, examined the possibility that inflammatory cytokines affect the synthesis of other enterocyte integral membrane proteins using lactase as a prototype, and examined the possibility that SI gene expression was down-regulated in villous enterocytes in vivo during the local inflammatory response of Crohn's disease. The results show that IL-6 and IFN gamma each mediate a decrease and TNF alpha mediates an increase in synthesis of SI in Caco2 cells. The magnitude of down-regulation by IL-6 and IFN gamma is significantly greater than the up-regulation by TNF alpha. IL-1 beta has no effect on synthesis of SI. Synthesis of lactase is not affected by any of the cytokines. There is a marked specific decrease in SI gene expression in villous enterocytes in acutely inflamed Crohn's ileum as compared to adjacent uninflamed ileum and normal ileum. Taken together, these data show that inflammatory cytokines have specific and selective effects on the expression of the brush border hydrolase SI in tissue culture and in vivo and provide evidence for a previously unrecognized mechanism for disaccharidase deficiency in intestinal inflammation.
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PMID:Regulation of sucrase-isomaltase gene expression in human intestinal epithelial cells by inflammatory cytokines. 855 56

Controversial information is available regarding the feed efficiency-related variation in intestinal size, structure and functionality in pigs. The present objective was therefore to investigate the differences in visceral organ size, intestinal morphology, mucosal enzyme activity, intestinal integrity and related gene expression in low and high RFI pigs which were reared at three different geographical locations (Austria, AT; Northern Ireland, NI; Republic of Ireland, ROI) using similar protocols. Pigs (n = 369) were ranked for their RFI between days 42 and 91 postweaning and low and high RFI pigs (n = 16 from AT, n = 24 from NI, and n = 60 from ROI) were selected. Pigs were sacrificed and sampled on ~day 110 of life. In general, RFI-related variation in intestinal size, structure and function was small. Some energy saving mechanisms and enhanced digestive and absorptive capacity were indicated in low versus high RFI pigs by shorter crypts, higher duodenal lactase and maltase activity and greater mucosal permeability (P < 0.05), but differences were mainly seen in pigs from AT and to a lesser degree in pigs from ROI. Additionally, low RFI pigs from AT had more goblet cells in duodenum but fewer in jejunum compared to high RFI pigs (P < 0.05). Together with the lower expression of TLR4 and TNFA in low versus high RFI pigs from AT and ROI (P < 0.05), these results might indicate differences in the innate immune response between low and high RFI pigs. Results demonstrated that the variation in the size of visceral organs and intestinal structure and functionality was greater between geographic location (local environmental factors) than between RFI ranks of pigs. In conclusion, present results support previous findings that the intestinal size, structure and functionality do not significantly contribute to variation in RFI of pigs.
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PMID:Finishing pigs that are divergent in feed efficiency show small differences in intestinal functionality and structure. 2838 12