Project description:Human embryonic stem cells (WA01) were differentiated in a step-wise manner into three-dimensional human gastric organoids (hGOs). At day 34 of differentiation, the hGOs were collected and analyzed by RNA-sequencing.
Project description:We previously established long-term 3D organoid culture systems for several murine tissues (intestine, stomach, pancreas and liver) as well as human intestine and pancreas. Here, we describe culture conditions to generate long-term 3D culture from human gastric stem cells. The technology can be applied to study the epithelial response to infection with Helicobacter pylori. Human gastric cultures can expand indefinitely in 3D Matrigel. Cultures can be generated from normal tissue, from single sorted stem cells, or from tumor tissue. Organoids maintain many characteristics of the respective tissue in terms of histology, marker expression and euploidy. Organoids from normal tissue express markers of four lineages of the stomach and self-organize in gland and pit-domains. They can be directed to specifically express either lineages of the gastric gland, or the gastric pit by addition of Nicotinamide and withdrawal of Wnt. While gastric pit lineages react marginally to bacterial infection, gastric gland lineages mount a strong inflammatory response. The gastric culture system provides a unique tool to study gastric pathologies. We generated 2 sets of experiments. The first set contains organoids in 4 conditions: (1) organoids in expansion condition ENRWFGNiTi ("gland-type organoids") from 3 donors, (2) organoids as in 1 but differentiated for 4 days in differentiation condition ENR_FGNiTi ("pit'type organoids"), (3) organoids as in 1 but infected with Helicobacter pylori strain P12 MOI 50 for 2 h, (4) organoids as in 2 but infected as in 3. All 4 conditions were tested on the same organoid line in parallel. This experiment was conducted independently with cultures from 3 different donors. The second set of experiments compares freshly isolated glands with organoids. Samples from 2 patients were analyzed. Each patient received a total gastrectomy. From each patient, glands from corpus region or pyloric antrum were isolated. From each isolation, one aliquod was stored for microarray analysis and one aliquod used to generate organoids. Organoids and glands were subsequently lysed and analyzed in parallel.
Project description:To understand the molecular basis of the acquisition of 5-FU resistance in gastric cancer stem cells, we established 5-FU-resistant gastric cancer organoids. We used microarrays to detail the global program of gene expression underlying 5-FU resistance and maintenance of stem cell properties in gastric cancer.
Project description:Coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a global public health emergency. COVID-19 typically manifests as a respiratory illness but an increasing number of clinical reports describe gastrointestinal (GI) symptoms. This is particularly true in children in whom GI symptoms are frequent and viral shedding outlasts viral clearance from the respiratory system. By contrast, fetuses seem to be rarely affected by COVID-19, although the virus has been detected in placentas of affected women. These observations raise the question of whether the virus can infect and replicate within the stomach once ingested. Moreover, it is not yet clear whether active replication of SARS-CoV-2 is possible in the stomach of children or in fetuses at different developmental stages. Here we show the novel derivation of fetal gastric organoids from 8-21 post-conception week (PCW) fetuses, and from pediatric biopsies, to be used as an in vitro model for SARS-CoV-2 gastric infection. Gastric organoids recapitulate human stomach with linear increase of gastric mucin 5AC along developmental stages, and expression of gastric markers pepsinogen, somatostatin, gastrin and chromogranin A. In order to investigate SARS-CoV-2 infection with minimal perturbation and under steady-state conditions, we induced a reversed polarity in the gastric organoids (RP-GOs) in suspension. In this condition of exposed apical polarity, the virus can easily access viral receptor angiotensin-converting enzyme 2 (ACE2). The pediatric RP-GOs are fully susceptible to infection with SARS-CoV-2, where viral nucleoprotein is expressed in cells undergoing programmed cell death, while the efficiency of infection is significantly lower in fetal organoids. The RP-GOs derived from pediatric patients show sustained robust viral replication of SARS-CoV-2, compared with organoids derived from fetal stomachs. Transcriptomic analysis shows a moderate innate antiviral response and the lack of differentially expressed genes belonging to the interferon family. Collectively, we established the first expandable human gastric organoid culture across fetal developmental stages, and we support the hypothesis that fetal tissue seems to be less susceptible to SARS-CoV-2 infection, especially in early stages of development. However, the virus can efficiently infect gastric epithelium in pediatric patients, suggesting that the stomach might have an active role in fecal-oral transmission of SARS-CoV-2.
Project description:Recent sequencing analyses have shed light on heterogeneous patterns of genomic aberrations in human gastric cancers (GCs). To explore how individual genetic events translate into cancer phenotypes, we established a biological library consisting of genetically engineered gastric organoids carrying various GC mutations and 37 patient-derived organoid lines, including rare genomically stable GCs. Phenotype analyses of GC organoids revealed divergent genetic and epigenetic routes to gain Wnt and R-spondin niche independency. An unbiased phenotype-based genetic screening identified a significant association between CDH1/TP53 compound mutations and the R-spondin independency that was functionally validated by CRISPR-based knockout. Xenografting of GC organoids further established the feasibility of Wnt-targeting therapy for Wnt-dependent GCs. Our results collectively demonstrate that multifaceted genetic abnormalities render human GCs independent of the stem cell niche and highlight the validity of the genotype-phenotype screening strategy in gaining deeper understanding of human cancers.
Project description:We treated mouse gastric organoids with Helicobacter pylori, Fusobacterium nucleatum, and Neisseria subflava, and extracted RNA after 4 hours. RNAs were applied to RNA sequencing analysis to investigate bacteria-specific effects on gastric epithelial cells.