Project description:To identify the molecular pathways that are perturbed due to transient zinc chelation Zinc is known to regulate the functions of about 10% of the human proteome and a large number of physiological processes that are zinc dependent have been identified and characterized under conditions of zinc deficiency and supplementation. As zinc homeostasis is closely linked to the normal functioning of both prokaryotic and eukaryotic cells, many pathogens are directly or indirectly affected by perturbations in zinc homeostasis. Dengue virus (DENV), a mosquito-borne, positive-strand RNA virus from the family Flaviviridae, has emerged as one of the major public health concerns in India and recent estimates suggest that over 60 million people globally get infected with DENV every year. The crystal structures of NS5 protein of DENV and West Nile virus have identified zinc binding site in RdRp domain and propose an important structural role for zinc ions in polymerase activity. Therefore, we investigated whether perturbation in intracellular zinc pools influence dengue infection. We utilized N,N,N’,N’-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN), a zinc-specific chelator, to mimic zinc-deficiency in cell culture models of infection and investigated the effect of zinc depletion on DENV life-cycle.
Project description:Zinc-regulated gene expression in intestinal (Caco-2) and placental (JAR) cell-lines, after 12h or 24h exposure to different zinc concentrations
Project description:We investigated transcriptional response of CaCo-2 cells to iron treatments, we studied hemin effect by adding hemin to DMEM-FBS medium and iron deficiency effects in using an iron free medium compared to the same supplemented with FAC (ferric ammonium citrate). Keywords: various iron treatment, differential gene expression, hemin treatment, iron-free
Project description:Background: 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, in this study we explored the applicability of an in vitro model, namely human intestinal Caco-2 cells, to study the effect of food compounds on (intestinal) health. 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 their mode of actions in the intestinal cells. Methods: Caco-2 cells were incubated with in vitro digested onion extracts for 6 hours, total RNA was extracted and Affymterix Human Gene 1.1 ST arrays were used to analyze the gene expression profiles. To identify onion-induced gene expression profiles in Caco-2 cells, digested yellow onion and white onion samples were compared to a digest control samples. Results: We found that yellow onion (n=5586, p<0.05) had a more pronounced effect on gene expression than white onion (n=3688, p<0.05). However, a substantial number of genes (n=3281, p<0.05) were affected by both onion variants in the same direction. Pathway analyses revealed that mainly processes related to oxidative stress, and especially the Keap1-Nrf2 pathway, were affected by onions. Our data fit with previous in vivo studies showing that the beneficial effects of onions are mostly linked to their antioxidant properties. Conclusion: our data indicate that the in vitro Caco-2 intestinal model 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.
Project description:We previously identified the ZTRE in genes involved in zinc homeostasis and showed that it mediates transcriptional repression in response to zinc. We now report that ZNF658 acts at the ZTRE. ZNF658 was identified by MALDI-TOF mass spectrometry of a band excised after EMSA using a ZTRE probe. The protein contains a KRAB domain and 21 zinc fingers. It has similarity with ZAP1 from Saccharomyces cerevisiae, which regulates the response to zinc restriction, including a conserved DNA binding region we show to be functional also in ZNF658. siRNA targeted to ZNF658 abrogated the zinc-induced, ZTRE-dependent reduction in SLC30A5 (ZnT5), SLC30A10 (ZnT10) and CBWD transcripts in human Caco-2 cells and the ability of zinc to repress reporter gene expression from corresponding promoter-reporter constructs. Microarray analysis of the effect of reducing ZNF658 expression by siRNA uncovered large changes in rRNA. We find that ZTREs are clustered within the 45S rRNA precursor. We also saw effects on expression of multiple ribosomal proteins. ZNF658 thus links zinc homeostasis with ribosome biogenesis, the most active transcriptional, and hence zinc-demanding, process in the cell. ZNF658 is thus a novel transcriptional regulator that plays a fundamental role in the orchestrated cellular response to zinc availability.
Project description:Transcriptional profile of 21-days differentiated Caco-2 cells compared to Caco-2 cycling cells. Goal was to demonstrate the ability of Caco-2 cells to express most of the markers typical of differentiated enterocytes. A novel protocol of line maintenance was used.
Project description:The effect of CLA on gene expression in Caco-2 cells Experiment Overall Design: Caco-2 cells were treated with linoleic acid (LA; the parent and control fatty acid) trans-10, cis-12 CLA or cis-9, trans-11 CLA for 12 d.