Project description:The purpose of this study was to characterise iPSC-derived human intestinal epithelial organoids (iPSCo) by comparing these cultures with primary purified intestinal epithelial cells (IEC). Intestinal epithelial organoid (IEO) cultures were derived from at least three different lines of iPSCs, RNA was extracted and gene expression was profiled using RNA-sequencing. We compared these profiles with datasets we have previously derived from purified IEC from mature terminal ileum (TI) and sigmoid colon (SC) as well as human fetal proximal gut (FPG) and fetal distal gut (FDG).
Project description:The purpose of this study was to characterise iPSC-derived human intestinal epithelial organoids (iPSCo) by comparing these cultures with primary purified intestinal epithelial cells (IEC). Intestinal epithelial organoid (IEO) cultures were derived from at least three different lines of iPSCs, DNA was extracted and gene expression was profiled using Illumina Infinium HumanMethylation450Beadarray. We compared these profiles with datasets we have previously derived from purified IEC from mature terminal ileum (TI) and sigmoid colon (SC) as well as human fetal proximal gut (FPG) and fetal distal gut (FDG).
Project description:We developed a compartmental model of the small intestinal epithelium that describes stem and progenitor cell proliferation and differentiation and cell migration onto the villus. The model includes a negative feedback loop from villus cells to regulate crypt proliferation and integrates heterogeneous epithelial-related processes, such as the transcriptional profile, citrulline kinetics and probability of diarrhea.
Project description:Aim: RNA binding proteins (RBPs) are emerging as critical regulators of gut homeostasis via post-transcriptional control of key growth and repair pathways. IMP1 (IGF2 mRNA Binding Protein 1) is ubiquitously expressed during embryonic development and Imp1 hypomorphic mice exhibit severe gut growth defects. In the present study, we investigated the mechanistic contribution of intestinal epithelial IMP1 to gut homeostasis and response to injury. Method: We evaluated IMP1 expression in patients with Crohn’s disease followed by unbiased ribosome profiling in IMP1 knockout cells. Concurrently, we measured differences in histology and cytokine expression in mice with intestinal epithelial-specific Imp1 deletion (Imp1ΔIEC) following dextran sodium sulfate (DSS)- colitis. Based on ribosome profiling analysis, we evaluated changes in autophagy in Imp1ΔIEC mice as well as in silico and in vitro approaches to evaluate direct protein:RNA interactions. Finally, we analyzed the consequence of genetic deletion of Atg7 in Imp1ΔIEC mice using colitis and irradiation models. Results: IMP1 was robustly upregulated in Crohn’s disease patients and Imp1 loss lessened DSS-colitis severity. Unbiased ribosome-profiling revealed that IMP1 may coordinate translation of multiple pathways important for intestinal homeostasis, including cell cycle and autophagy, which we verified by Western blotting. Mechanistically, we observed evidence for increased autophagy flux in Imp1ΔIEC mice, reinforced through in silico and biochemical analyses revealing direct binding of IMP1 to autophagy transcripts. Finally, we found genetic deletion of Atg7 reversed the phenotype observed in DSS- or irradiation-challenged Imp1ΔIEC mice. Conclusions: IMP1 acts as a post-transcriptional regulator of gut epithelial repair, in part through modulation of autophagy. This study highlights the need for examining post-transcriptional regulation as a critical mechanism in inflammatory bowel disease.
Project description:A human gut-on-a-chip microdevice was used to coculture multiple commensal microbes in contact with living human intestinal epithelial cells for more than a week in vitro and to analyze how gut microbiome, inflammatory cells, and peristalsis-associated mechanical deformations independently contribute to intestinal bacterial overgrowth and inflammation. This in vitro model replicated results from past animal and human studies, including demonstration that probiotic and antibiotic therapies can suppress villus injury induced by pathogenic bacteria. By ceasing peristalsis-like motions while maintaining luminal flow, lack of epithelial deformation was shown to trigger bacterial overgrowth similar to that observed in patients with ileus and inflammatory bowel disease. Analysis of intestinal inflammation on-chip revealed that immune cells and lipopolysaccharide endotoxin together stimulate epithelial cells to produce four proinflammatory cytokines (IL-8, IL-6, IL-1β, and TNF-α) that are necessary and sufficient to induce villus injury and compromise intestinal barrier function. Thus, this human gut-on-a-chip can be used to analyze contributions of microbiome to intestinal pathophysiology and dissect disease mechanisms in a controlled manner that is not possible using existing in vitro systems or animal models. 6 samples, 2 biological replicates for each 3 conditions.
Project description:The innate immune response of mucosal epithelial cells during pathogen invasion plays a central role in immune regulation in the gut. Toxoplasma gondii (T. gondii) is a protozoan intracellular parasite that is usually transmitted through oral infection. Although much of the information on immunity to T. gondii has come from intra-peritoneal infection models, more recent studies have revealed the importance of studying immunity following infection through the natural per-oral route. Oral infection studies have identified many of the key players in the intestinal response; however, they have relied on responses detected days to weeks following infection. Much less is known about how the gut epithelial layer senses and reacts during initial contact with the pathogen. Given the importance of epithelial cells during pathogen invasion, this study uses an in vitro approach to isolate the key players and examine the early response of intestinal epithelial cells during infection by T. gondii. We show that human intestinal epithelial cells infected with T. gondii elicit rapid MAPK phosphorylation, NF-κB nuclear translocation, and secretion of interleukin (IL)-8. Both ERK1/2 activation and IL-8 secretion responses were shown to be MyD88 dependent and TLR2 was identified to be involved in the recognition of the parasite regardless of the parasite genotype. Furthermore, we were able to identify additional T. gondii-regulated genes in the infected cells using a pathway-focused array. Together, our findings suggest that intestinal epithelial cells were able to recognize T. gondii during infection, and the outcome is important for modulating intestinal immune responses. Oral infection studies have demonstrated an increase in several cytokines and chemokines in response to T.gondii infection; however, the mixed population of the intestinal mucosa did not allow for the determination of the relative role that specific cell populations play in the production of these mediators. To address the role of intestinal epithelial cells to modulate the cytokine environment early following infection, we used specific pathway arrays to identify cytokines and chemokines induced 4 hours after exposure to T. gondii. At this time point most cells have become infected, but the parasites have not replicated.
Project description:The innate immune response of mucosal epithelial cells during pathogen invasion plays a central role in immune regulation in the gut. Toxoplasma gondii (T. gondii) is a protozoan intracellular parasite that is usually transmitted through oral infection. Although much of the information on immunity to T. gondii has come from intra-peritoneal infection models, more recent studies have revealed the importance of studying immunity following infection through the natural per-oral route. Oral infection studies have identified many of the key players in the intestinal response; however, they have relied on responses detected days to weeks following infection. Much less is known about how the gut epithelial layer senses and reacts during initial contact with the pathogen. Given the importance of epithelial cells during pathogen invasion, this study uses an in vitro approach to isolate the key players and examine the early response of intestinal epithelial cells during infection by T. gondii. We show that human intestinal epithelial cells infected with T. gondii elicit rapid MAPK phosphorylation, NF-κB nuclear translocation, and secretion of interleukin (IL)-8. Both ERK1/2 activation and IL-8 secretion responses were shown to be MyD88 dependent and TLR2 was identified to be involved in the recognition of the parasite regardless of the parasite genotype. Furthermore, we were able to identify additional T. gondii-regulated genes in the infected cells using a pathway-focused array. Together, our findings suggest that intestinal epithelial cells were able to recognize T. gondii during infection, and the outcome is important for modulating intestinal immune responses.