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ABSTRACT: Carnosine is a physiologically important molecule in normal human body functions. Chicken meat is an excellent source of carnosine; especially slow-growing Korat chicken (KR) females have a high carnosine content in their meat. The carnosine content of chicken meat can be increased by dietary supplementation of β-alanine (βA) and L-histidine (L-His). Our objective was to reveal the pathways and genes through jejunal transcriptomic profiling related to βA and L-His absorption and transportation. We collected whole jejunum samples from 5 control and 5 experimental KR chicken, fed with 1% βA and 0.5% L-His supplementation. A total of 407 differentially expressed genes (P < 0.05, log2 fold change ≥2) were identified, 272 of which were down-regulated and 135 up-regulated in the group with dietary supplementation compared to the control group. Based on the integrated analysis of the protein–protein interaction network and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway maps, 87 gene ontology terms were identified and 6 KEGG pathways were significantly (P < 0.05) enriched in the jejunum. The analyses revealed 6 key genes, KCND3, OPRM1, CCK, GCG, TRH, and GABBR2, that are related to neuroactive ligand-receptor interaction and the calcium signaling pathway. These findings give insight regarding the molecular mechanism related to carnosine precursor absorption and transportation in the jejunum and help to identify useful molecular markers for improving the carnosine content in slow-growing KR chicken meat.

Inhabitants of rural Niger-Delta oil communities in Nigeria often, unintentionally, consume crude oil polluted water (COCW) due to crude oil spills in the region. The impact of vitamin C supplementation during COCW ingestion on the contractile mechanism of the jejunum is not fully known. Hence, this study investigates the outcomes of COCW water and vitamin C intake on the smooth muscle activity of the jejunum in Wistar rats using standard techniques. Data obtained showed that jejunal tissue SOD concentration was significantly reduced, while jejunal tissue MDA concentration was significantly increased in the COCW-only treated group. Contraction mediated by acetylcholine was significantly increased in the COCW-only treated rats. Calcium and potassium ion influx significantly increased jejunal contraction in the COCW-only rats. Incubation of the jejunal tissue in nifedipine, indomethacin, and L-NAME significantly increased acetylcholine-mediated contractions in the jejunal tissue of the COCW-only treated rats when compared to other groups. COCW causes free radical-induced jejunal damage that results in impaired jejunal contractile activity mediated by the M2 muscarinic receptor, nitric oxide synthase activity, voltage-gated large-conductance calcium channels, potassium channels, and prostaglandins. However, the oral intake of Vitamin C supplementation significantly ameliorated impairments by enhancing jejunal antioxidant activity. [ABSTRACT FROM AUTHOR]

Inhabitants of rural Niger-Delta oil communities in Nigeria often, unintentionally, consume crude oil polluted water (COCW) due to crude oil spills in the region. The impact of vitamin C supplementation during COCW ingestion on the contractile mechanism of the jejunum is not fully known. Hence, this study investigates the outcomes of COCW water and vitamin C intake on the smooth muscle activity of the jejunum in Wistar rats using standard techniques. Data obtained showed that jejunal tissue SOD concentration was significantly reduced, while jejunal tissue MDA concentration was significantly increased in the COCW-only treated group. Contraction mediated by acetylcholine was significantly increased in the COCW-only treated rats. Calcium and potassium ion influx significantly increased jejunal contraction in the COCW-only rats. Incubation of the jejunal tissue in nifedipine, indomethacin, and L-NAME significantly increased acetylcholine-mediated contractions in the jejunal tissue of the COCW-only treated rats when compared to other groups. COCW causes free radical-induced jejunal damage that results in impaired jejunal contractile activity mediated by the M2 muscarinic receptor, nitric oxide synthase activity, voltage-gated large-conductance calcium channels, potassium channels, and prostaglandins. However, the oral intake of Vitamin C supplementation significantly ameliorated impairments by enhancing jejunal antioxidant activity.

Carnosine is a physiologically important molecule in normal human body functions. Chicken meat is an excellent source of carnosine; especially slow-growing Korat chicken (KR) females have a high carnosine content in their meat. The carnosine content of chicken meat can be increased by dietary supplementation of β-alanine (βA) and L-histidine (L-His). Our objective was to reveal the pathways and genes through jejunal transcriptomic profiling related to βA and L-His absorption and transportation. We collected whole jejunum samples from 5 control and 5 experimental KR chicken, fed with 1% βA and 0.5% L-His supplementation. A total of 407 differentially expressed genes (P < 0.05, log 2 fold change ≥2) were identified, 272 of which were down-regulated and 135 up-regulated in the group with dietary supplementation compared to the control group. Based on the integrated analysis of the protein–protein interaction network and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway maps, 87 gene ontology terms were identified and 6 KEGG pathways were significantly (P < 0.05) enriched in the jejunum. The analyses revealed 6 key genes, KCND3, OPRM1, CCK, GCG, TRH, and GABBR2, that are related to neuroactive ligand-receptor interaction and the calcium signaling pathway. These findings give insight regarding the molecular mechanism related to carnosine precursor absorption and transportation in the jejunum and help to identify useful molecular markers for improving the carnosine content in slow-growing KR chicken meat. [ABSTRACT FROM AUTHOR]

Background Induction or inhibition of drug transporting proteins by concomitantly administered drugs can cause serious drug-drug interactions (DDIs). However, in vitro assays currently available are mostly for studying the inhibitory potential of drugs on intestinal transporter proteins, rather than induction. Therefore, this study investigated the suitability of the frequently used intestinal Caco-2 cell line to predict transporter-mediated DDIs as caused by induction via activation of nuclear receptors. Methods TaqMan® low density arrays and LC-MS/MS based targeted proteomics were used to evaluate transporter expression in Caco-2 cells in comparison with jejunal tissue, in culture-time dependence studies and after incubation with different known inducers of drug metabolism and transport. Additionally, studies on ABCB1 function were performed using Transwell® assays with [3H]-digoxin and [3H]-talinolol as substrates after incubation with the prototypical inducers rifampicin, St John's wort, carbamazepine and efavirenz. Results The gene and protein expression pattern of drug transporters in Caco-2 cells and jejunal tissue differed considerably. For some transporters culture-time dependent differences in mRNA expression and/or protein abundance could be determined. Finally, none of the studied prototypical inducers showed an effect either on mRNA expression and protein abundance or on the function of ABCB1. Conclusion Differences in transporter expression in Caco-2 cells compared with jejunal tissue, as well as expression dependence on culture time must be considered in in vitro studies to avoid under- or overestimation of certain transporters. The Caco-2 cell model is not suitable for the evaluation of DDIs caused by transporter induction. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]