Project description:The aim was to investigate mechanisms contributing to quercetinâs previously described effects on cell-proliferation and -differentiation, which contradicted its proposed anti-carcinogenic potency. In a 10-day experiment, 40 µM quercetin stabilized by 1mM ascorbate reduced Caco-2 differentiation up to 50% (P<0.001). Caco-2 RNA from days 5 and 10, hybridized on HG-U133A2.0 Affymetrix® GeneChips®, showed 1,743 affected genes on both days (P<0.01). All 14 Caco-2 differentiation-associated genes showed decreased expression (P<0.01), including intestinal alkaline phosphatase that was confirmed technically (qRT-PCR) and functionally (enzyme-activity). The 1,743 genes contributed to 27 affected pathways (P<0.05) categorized under 6 gene ontology (GO) processes, including apoptosis and cell-cycle. Genes within these GO-processes showed fold changes that suggest increased cell-survival and -proliferation. Furthermore, quercetin downregulated expression of genes involved in tumor-suppression and phase II metabolism, and upregulated oncogenes. Gene expression changes mediated by ascorbate-stabilized quercetin were concordant with those occurring in human colorectal carcinogenesis (â 80-90%), but were opposite to those previously described for Caco-2 cells exposed to quercetin in the absence of ascorbate (â 75-90%). In conclusion, gene expression among Caco-2 cells exposed to ascorbate-stabilized quercetin showed mechanisms contrary to what is expected for a cancer-preventive agent. Whether this unexpected in vitro effect is relevant in vivo, remains to be elucidated. Experiment Overall Design: Caco-2 cells were harvested on days 5 and 10 post-confluency. Per day, fold changes were calculated as quercetin vs. control.
Project description:The aim was to investigate mechanisms contributing to quercetin’s previously described effects on cell-proliferation and -differentiation, which contradicted its proposed anti-carcinogenic potency. In a 10-day experiment, 40 µM quercetin stabilized by 1mM ascorbate reduced Caco-2 differentiation up to 50% (P<0.001). Caco-2 RNA from days 5 and 10, hybridized on HG-U133A2.0 Affymetrix® GeneChips®, showed 1,743 affected genes on both days (P<0.01). All 14 Caco-2 differentiation-associated genes showed decreased expression (P<0.01), including intestinal alkaline phosphatase that was confirmed technically (qRT-PCR) and functionally (enzyme-activity). The 1,743 genes contributed to 27 affected pathways (P<0.05) categorized under 6 gene ontology (GO) processes, including apoptosis and cell-cycle. Genes within these GO-processes showed fold changes that suggest increased cell-survival and -proliferation. Furthermore, quercetin downregulated expression of genes involved in tumor-suppression and phase II metabolism, and upregulated oncogenes. Gene expression changes mediated by ascorbate-stabilized quercetin were concordant with those occurring in human colorectal carcinogenesis (≈ 80-90%), but were opposite to those previously described for Caco-2 cells exposed to quercetin in the absence of ascorbate (≈ 75-90%). In conclusion, gene expression among Caco-2 cells exposed to ascorbate-stabilized quercetin showed mechanisms contrary to what is expected for a cancer-preventive agent. Whether this unexpected in vitro effect is relevant in vivo, remains to be elucidated. Keywords: Colon cancer; Caco-2; quercetin; differentiation
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes
Project description:The generation of pancreatic organoids from human pluripotent stem cells represents a major breakthrough for regenerative medicine and the modeling of diseases such as diabetes. However, current approaches remain inefficient due to lengthy multi-step differentiation protocols and limited functional maturity in the organoids. In this study, we overcome these challenges using multi-phase optimization screens to achieve rapid generation of functionally mature pancreatic organoids from a stable endocrine progenitor culture. We conducted stepwise culture condition screens that enabled the stable culture of multiple pancreatic progenitor cell states, including the unprecedented stable propagation of NEUROD1-expressing endocrine progenitor-like cells (EpSCs). Further transcriptomic profiling of EpSC confirmed similarity of that to previously reported endocrine progenitor populations. Using EpSCs, we significantly reduced the number of steps and timing required to generate pancreatic organoids, enabling rapid testing of conditions for organoid maturation. Utilizing this optimized protocol, we further tested conditions to promote pancreatic organoid maturation. We identified that exosome-delivered WNT5B, in combination with RSPO1 (exoW/R), could strongly induce non-canonical WNT/JNK signaling, promoting pancreatic organoid maturation. This combinatorial exosome treatment enhances epithelial organization, reduces immature cell states, and significantly improves glucose responsiveness and insulin secretion. Collectively, our work establishes a robust pancreatic differentiation platform that integrates long-term progenitor expansion with optimized organoid maturation. This system provides a reproducible experimental framework for studying pancreatic development, investigating disease mechanisms, and facilitating future translational applications involving pancreatic organoids.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes Sequence library of miRNAs from a single sample of human foetal mesenchymal stem cells. Results tested and confirmed by northern blotting. Please note that only raw data files are available for the embryonic and neual samples and thus, directly submitted to SRA (SRX547311, SRX548700, respectively under SRP042115/PRJNA247767)
Project description:SPO11-promoted DNA double-strand breaks (DSBs) formation is a crucial step for meiotic recombination, and it is indispensable to detect the broken DNA ends accurately for dissecting the molecular mechanisms behind. Here, we report a novel technique, named DEtail-seq (DNA End tailing followed by sequencing), that can directly and quantitatively capture the meiotic DSB 3’ overhang hotspots at single-nucleotide resolution.