Project description:Cell clones that lack P53 signaling occur frequently in ulcerative colitis (UC) and are considered drivers in UC-associated colorectal cancer. Trp53 mutant cells often display decreased P53 signaling and have previously been shown to outcompete wild type (WT) cells in a mouse model of colitis (DSS colitis), but not in healthy mice. However, the mechanism responsible for the observed context-dependent effects of P53 are not understood. Therefore, we aimed to explore this by studying the behavior of Trp53-deficient cells specifically in injured mucosa. We have developed murine and organoid-based models to study the context dependent role of Trp53 knock-out (KO). We use inducible KO systems in mouse models of DSS colitis to study the loss of Trp53 in the injury and regenerative state. Colon organoids are employed to recapitulate the in vivo findings in order to elucidate the pathways involved.
Project description:The capacity to regenerate the spinal cord after an injury is a coveted trait that only a limited group of non-mammalian organisms can achieve. In Xenopus laevis, this capacity is only present during larval or tadpole stages, but is absent during postmetamorphic frog stages. This provides an excellent model for comparative studies between a regenerative and a non-regenerative stage to identify the cellular and molecular mechanisms that explain the difference in regenerative potential. Here, we used iTRAQ chemistry to obtain a quantitative proteome of the spinal cord 1 day after a transection injury, and used sham operated animals as controls. We quantified a total of 6,384 proteins, with 172 showing significant differential expression in the regenerative stage and 240 in the non-regenerative stage, with an overlap of only 14 proteins. Functional enrichment analysis revealed that while the regenerative stage downregulated synapse/vesicle and mitochondrial proteins, the non-regenerative stage upregulated lipid metabolism proteins, and downregulated ribosomal and translation control proteins. Furthermore, STRING network analysis showed that proteins belonging to these groups are highly interconnected, providing interesting candidates for future functional studies.
Project description:The samples are a part of a study aiming at diagnosing ulcerative colitis from genome-wide gene expression analysis of the colonic mucosa. Colonic mucosal samples were collected as endoscopic pinch biopsies from ulcerative colitis patients and from control subjects. Samples with and without macroscopic signs of inflammation were collected from the patients. Experiment Overall Design: The series contain eight UC samples with macroscopic signs of inflammation, 13 UC smaples without macroscopic signs of inflammation, five control subjects.
Project description:The samples are a part of a study aiming at diagnosing ulcerative colitis from genome-wide gene expression analysis of the colonic mucosa. Colonic mucosal samples were collected as endoscopic pinch biopsies from ulcerative colitis patients and from control subjects. Samples with and without macroscopic signs of inflammation were collected from the patients. Keywords: Disease state analysis
Project description:The intestinal epithelium forms a barrier to the lumen and ensures uptake of vital nutrients. During inflammatory diseases, such as ulcerative colitis (UC), this barrier is compromised. Here, we perform single-cell RNA sequencing (scRNA-seq) of epithelial cells and outline patterns of cell fate decisions in healthy individuals and patients with UC. We demonstrate that lineage biased progenitors are major sources of normal tissue replenishment, and that patterns of cell behavior are profoundly altered in UC. We furthermore identify unique regenerative cell states linked to JAK/STAT activation extending into the non-inflamed areas of the colon. In organoid models, this can be mimicked by cytokine mediated activation of JAK/STAT leading to the emergence of cell populations with regenerative potential. These findings have profound implications for our understanding of tissue regeneration and illustrates how cytokine signaling influences cell fate decisions. This suggests widespread consequences in patients with chronic ulcerative conditions.