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Human intestinal tissue samples are barely accessible to study potential health benefits of nutritional compounds. Numbers of animals used in animal trials, however, need to be minimalized. Therefore, we explored the applicability of in vitro (human Caco-2 cells) and ex vivo intestine models (rat precision cut intestine slices and the pig in-situ small intestinal segment perfusion (SISP) technique) to study the effect of food compounds. In vitro digested yellow (YOd) and white onion extracts (WOd) were used as model food compounds and transcriptomics was applied to obtain more insight into which extent mode of actions depend on the model. The three intestine models shared 9,140 genes which were used to compare the responses to digested onions between the models. Unsupervised clustering analysis showed that genes up- or down-regulated by WOd in human Caco-2 cells and rat intestine slices were similarly regulated by YOd, indicating comparable modes of action for the two onion species. Highly variable responses to onion were found in the pig SISP model. By focussing only on genes with significant differential expression, in combination with a fold change > 1.5, 15 genes showed similar onion-induced expression in human Caco-2 cells and rat intestine slices and 2 overlapping genes were found between the human Caco-2 and pig SISP model. Pathway analyses revealed that mainly processes related to oxidative stress, and especially the Keap1-Nrf2 pathway, were affected by onions in all three models. Our data fit with previous in vivo studies showing that the beneficial effects of onions are mostly linked to their antioxidant properties. Taken together, our data indicate that each of the in vitro and ex vivo intestine models used in this study, taking into account their limitations, can be used to determine modes of action of nutritional compounds and can thereby reduce the number of animals used in conventional nutritional intervention studies.

Rat small intestine precision cut slices were exposed for 6 hours to in vitro digested yellow (YOd) and white onion extracts (WOd) that was followed by transcriptomics analysis. The digestion was performed to mimic the digestion that in vivo takes place in the stomach and small intestine. The transcriptomics response of the rat small intestine precision cut slices was compared to that of human Caco-2 cells and the pig in-situ small intestinal segment perfusion. The microarray data for the human Caco-2 cells (GSE83893) and the pig in-situ small intestinal segment perfusion (GSE83908) have been submitted separately from the current data on rat intestine. The goal was to obtain more insight into to which extent mode of actions depend on the experimental model. A main outcome was that each of the three models pointed to the same mode of action: induction of oxidative stress and particularly the Keap1-Nrf2 pathway.

Background: Studies in mice have shown that PPARα is an important regulator of lipid metabolism in liver and key transcription factor involved in the adaptive response to fasting. However, much less is known about the role of PPARα in human liver. Methods: Here we set out to study the function of PPARα in human liver via analysis of whole genome gene regulation in human liver slices treated with the PPARα agonist Wy14643. Results: Quantitative PCR indicated that PPARα is well expressed in human liver and human liver slices and that the classical PPARα targets PLIN2, VLDLR, ANGPTL4, CPT1A and PDK4 are robustly induced by PPARα activation. Transcriptomics analysis indicated that 617 genes were upregulated and 665 genes were downregulated by PPARα activation (q value < 0.05). Many genes induced by PPARα activation were involved in lipid metabolism (ACSL5, AGPAT9, FADS1, SLC27A4), xenobiotic metabolism (POR, ABCC2, CYP3A5) or the unfolded protein response, whereas most of the downregulated genes were involved in immune-related pathways. Among the most highly repressed genes upon PPARα activation were several chemokines (e.g. CXCL9-11, CCL8, CX3CL1, CXCL6), interferon γ-induced genes (e.g. IFITM1, IFIT1, IFIT2, IFIT3) and numerous other immune-related genes (e.g. TLR3, NOS2, and LCN2). Comparative analysis of gene regulation by Wy14643 between human liver slices and primary human hepatocytes showed that down-regulation of gene expression by PPARα is much better captured by liver slices as compared to primary hepatocytes. In particular, PPARα activation markedly suppressed immunity/inflammation-related genes in human liver slices but not in primary hepatocytes. Finally, several putative new target genes of PPARα were identified that were commonly induced by PPARα activation in the two human liver model systems, including TSKU, RHOF, CA12 and VSIG10L. Conclusion: Our paper demonstrates the suitability and superiority of human liver slices over primary hepatocytes for study

Background Unexpected cholestasis substantially contributes to drug failure in clinical trials. Current models used for safety assessment in drug development do not accurately predict cholestasis in humans. Therefore, it is of relevance to develop new screening models that allow identifying drugs with cholestatic properties. Methods We employed mouse precision cut liver slices (PCLS), which were incubated 24 h with two model cholestatic compounds: cyclosporin A (CsA) and chlorpromazine (CPZ). Subsequently, transcriptome analysis using DNA microarrays and q-PCR were performed to identify relevant biological processes and biomarkers. Additionally, histology was carried out and levels of triglycerides (TG) and bile acids (BA) were measured. To verify the ex vivo mouse data, these were compared with publically available human data relevant for cholestasis. Results Whole genome gene expression analysis showed that CsA up-regulated pathways related to NF-¿B, ER stress and inflammation. Both CsA and CPZ down-regulated processes related to extracellular matrix (ECM) remodelling, BA homeostasis, Fxr signalling, and energy metabolism. The differential expression of a number of characteristic genes (e.g. Abcg5, Abcg8, Klf15, and Baat) could be confirmed by q-PCR. Histology revealed that CsA but not CPZ induced “ballooning” of hepatocytes. No effects on TG and BA levels were observed after incubation of PCLS with CsA and CPZ. A substantial number of processes altered in CsA- and CPZ-treated mouse PCLS ex vivo was also found to be affected in liver biopsies of cholestatic patients. Conclusion The present study demonstrated that mouse PCLS can be used as a tool to identify mechanisms of action of cholestatic model compounds. The induction of general stress responses and down-regulated Fxr signalling could play a role in the development of drug induced cholestasis. Importantly, comparative data analysis showed that the ex vivo mouse findings are also relevant for human pathology.

Pyrethrins are active ingredients extracted from pyrethrum flowers (Tanacetum cinerariifolium), and are the most widely used botanical insecticide. However, several thrips species are commonly found on pyrethrum flowers in the field, and are the dominant insects found inside the flowers. Up to 80% of western flower thrips (WFT, Frankliniella occidentalis) adults died within 3 days of initiating feeding on leaves of pyrethrum, leading us to evaluate the role of pyrethrins in the defense of pyrethrum leaves against WFT. The effects of pyrethrins on WFT survival, feeding behavior, and reproduction were measured both in vitro and in planta (infiltrated leaves). The lethal concentration value (LC50) for pyrethrins against WFT adults was 12.9 mg/ml, and pyrethrins at 0.1% (w/v) and 1% (w/v) had significantly negative effects on feeding, embryo development, and oviposition. About 20-70% of WFT were killed within 2 days when they were fed chrysanthemum leaves containing 0.01-1% pyrethrins. Chrysanthemum leaves containing 0.1% or 1% pyrethrins were significantly deterrent to WFT. In a no-choice assay, the reproduction of WFT was reduced significantly when the insects were fed leaves containing 0.1% pyrethrins, and no eggs were found in leaves containing 1% pyrethrins. Our results suggest that the natural concentrations of pyrethrins in the leaves may be responsible for the observed high mortality of WFT on pyrethrum

Constructs carrying visual reporter genes coupled with efficient promoters could facilitate the process of identification and selection of stable transformants in recalcitrant crops. Here, a novel construct utilizing a ribulose-1,5-bisphosphate carboxylase (RbcS) promoter combined with the green fluorescent protein (GFP) reporter gene to initiate very high expression of GFP in florist's chrysanthemum (Chrysanthemum morifolium Ramat.) was described. Based on this expression cassette, a new regeneration protocol using leaf discs as explants was developed for the Agrobacterium-mediated transformation of Chrysanthemum genotype ‘1581’, and a transformation efficiency of 7% was obtained. The expression of two different GFP constructs targeted to either cytosol or plastids was compared in transgenic lines. Both GFP constructs were expressed at such a high level that the green fluorescence dominated red fluorescence in the leaf tissues, allowing easy observation and microdissection of transformed tissues even without a GFP filter. Under normal light, plants with GFP targeted to plastids had a light green phenotype deriving from the high GFP expression. Quantitative reverse transcriptional PCR analysis showed that the plastid targeted construct with intron had significantly higher steady state transcript levels of GFP mRNA. This novel expression cassette may allow direct visual selection of transformed tissues independent of antibiotic selection in a wide range of plant species