Project description:Cutaneous melanoma is an aggressive type of skin cancer with a complex genetic landscape caused by the malignant transformation of melanocytes. The study aimed at providing an in-silico network model based on the systematic profiling of the melanoma-associated genes considering germline mutations, somatic mutations, and genome-wide association studies (GWAS) signals (collectively melanoma risk genes). A protein-protein interaction network (melanoma risk network) was constructed using the melanoma risk genes to describe the functional landscape in which the melanoma genes operate within the cellular milieu. A significant portion of the melanoma risk network showed differential expression when SK-MEL-28 human melanoma cells were exposed to the phytochemicals harmine and berberine chloride reinforcing the hypothesis that network modelling may represent an alternative screening approach to prioritize potentially active compounds.
Project description:We developed and applied a scalable genetic screening approach, in vivo Perturb-Seq, to functionally evaluate 35 autism spectrum disorder/neurodevelopmental delay (ASD/ND) de novo loss-of-function risk genes (see https://www.biorxiv.org/content/10.1101/791525v1 for complete list). Using CRISPR-Cas9, we introduced frameshift mutations in these risk genes in pools, within the developing mouse brain in utero, followed by single-cell RNA sequencing of perturbed cells in the postnatal brain. We identified cell type-specific and evolutionarily conserved gene modules from both neuronal and glial cell classes. Recurrent gene modules and cell types are affected across this cohort of perturbations, representing key cellular effects across sets of ASD/ND risk genes.
Project description:It has been proposed that endogenously formed N-nitroso compounds (NOCs) are partly responsible for the link between red meat consumption and colorectal cancer (CRC) risk. As nitrite has been indicated as one of the critical factors in the formation of endogenous NOCs, it is of high importance to replace or reduce the nitrite levels in meat. Therefore, the PHYTOME project was initiated (Phytochemicals to reduce nitrite in meat products; www.phytome.eu), an EU funded research project aiming to develop innovative meat products in which the food additive sodium nitrite (E251) has been replaced by natural compounds originating from fruits and vegetables. A human dietary intervention study was conducted in which healthy subjects consumed 300 grams of meat for two weeks, in subsequent order: normal processed red meat, white meat, and red processed meat with standard or reduced levels of nitrite and added phytochemicals. Consumption of standard-nitrite PHYTOME meat products leads to a significant reduction in Apparent Total N-nitroso Compounds (ATNC) levels in faecal water, a surrogate marker of endogenously formed NOCs, as compared to the consumption of conventional processed red meat products. A reduction of nitrite in the PHYTOME meat lowered these levels even further. In addition, DNA strand breaks induced in ex-vivo faecal water exposed Caco-2 cells and O6-methyl-guanine adducts levels in colonic DNA were significantly higher after consumption of normal processed red meat as compared to white meat intake. PHYTOME meat intake resulted in reduced levels of these genotoxic markers, however, these were not statistically significant. Whole genome gene expression analyses in colonic tissue identified differentially expressed genes and genes associated with ATNC, which are related to molecular pathways which may explain cancer risk initiation after intake of processed red meat and cancer risk prevention after intake of the PHYTOME meat. Together these results indicate that addition of natural extracts to conventional processed red meat products results in reduced endogenous formation of NOCs, and may therefore contribute to a reduced risk of CRC, which is mechanistically supported by gene expression analyses.
Project description:In this study we use a (targeted) perturb seq experiment in which we knock out 22 transcription factors downstream of MAPK signalling in order to reconstruct the transcriptional network downstream of RAF/MAPK signaling.
Project description:Induced pluripotent stem cell (iPSC) derived organoid systems provide models to study human organ development. Single-cell transcriptome sequencing enables highly-resolved descriptions of cell state heterogeneity within these systems and computational methods can reconstruct developmental trajectories. However, new approaches are needed to directly measure lineage relationships in these systems. Here we establish an inducible dual channel lineage recorder, iTracer, that couples reporter barcodes, inducible CRISPR/Cas9 scarring, and single-cell transcriptomics to analyze state and lineage relationships in iPSC-derived systems. This data set include the iTracer-perturb data of one cerebral organoid with simultaneous TSC2 perturbation and lineage recording.
Project description:Study hypothesis: We hypothesise that both colon inflammation and a diet high in red meat increase the endogenous formation of potentially carcinogenic N-nitroso compounds in the human colon and that these compounds increase the colorectal cancer risk, which could (partially) explain the increased colorectal cancer risk that is associated with inflammatory bowel disease and diets high in red meat.
Inflammatory bowel disease is characterised by a chronic inflammation within the gastrointestinal tract, which, in case of ulcerative colitis, is present in the colon and rectum.
Primary outcome(s): 1. Whole genome gene expression modifications by microarray analysis (4x44K Agilent platform)
2. Apparent total nitroso compounds in faecal matter by thermal energy analysis
3. Faecal water genotoxicity (30 minute exposure to 10% faecal water) by comet assay analysis in the adenocarcinoma cell line Caco-2
All outcomes are measured at baseline and post intervention.
Project description:Pooled CRISPR screens with single-cell RNA-seq readout (Perturb-seq) have emerged as a key technique in functional genomics, but are limited in scale by cost and combinatorial complexity. Here, we reimagine Perturb-seq’s design through the lens of algorithms applied to random, low-dimensional observations. We present compressed Perturb-seq, in which we measure multiple perturbations per cell or multiple cells per droplet, and decompress these measurements by leveraging the sparse structure of regulatory circuits. Applying compressed Perturb-seq to 598 genes in the immune response to bacterial lipopolysaccharide, we achieve the same accuracy as conventional Perturb-seq at 4 to 20-fold reduced cost, with greater power to learn genetic interactions. We identify known and novel regulators of immune responses and uncover evolutionarily constrained genes with downstream targets enriched for immune disease heritability, including many missed by existing GWAS or trans-eQTL studies. Our framework enables new scales of interrogation for a foundational method in functional genomics.