Project description:Stomach and intestinal epithelial cells are maintained by the activity of stem cells located in the isthmus and crypt, respectively1,2. Recent studies have demonstrated a surprisingly conserved role for Wnt signaling in stomach and intestinal development and stem cells3,4. Although accumulating evidence suggests that intestinal stromal cells secrete Wnt ligands to promote stem cell renewal5-10, the source of stomach Wnt ligands is still unclear. Moreover, how these gastrointestinal stem cell niche signals are produced is currently unknown. By performing single cell analysis of gastrointestinal stromal cells, we identified cell populations with transcriptome signatures that are conserved between the stomach and intestine. In close proximity to gastrointestinal epithelial cells, these cells highly expressed pericyte markers and Wnt ligands. They also were enriched for Hh signaling, which plays a key role in gut development11,12. A recent study has shown that intestinal pericryptal cells co-express Hh target and Wnt ligand genes8. To define their relationship, we analyzed mice with Hh gain of function in the pericyte-like stromal cells conserved between the stomach and intestine, and found increased levels of Wnt ligands, supporting Hh regulation of stromal Wnt ligand expression. Moreover, utilizing Sufu and Spop double knockout mice, which stabilized GLI2, a key Hh mediator in the gut, we were able to map GLI2 binding sites genome-wide and analyze super enhancers. This work demonstrates GLI2 activation of stromal Wnt ligands through enhancers that are conserved between the stomach and intestine. To determine the significance of Wnt secreting gastrointestinal stromal cells, we genetically inhibited Wnt secretion from the perictye-like or broad stromal cells, demonstrating their roles in gastrointestinal regeneration and development, respectively. Our work not only identifies the conserved gastrointestinal stromal niche cell populations but also reveals their underlying signaling and epigenetic mechanisms.
Project description:Murine Adult Stomach Small RNA Stomach samples were collected from adult mice. Small RNA was isolated from samples and cDNA libraries were generated for PGM sequencing. Sequences were aligned with Torrent Server tMap.
Project description:We demonstrate the conserved Hh-GLI2-mediated chromatin and transcriptional regulation of both stomach and intestinal stromal stem cell niche signals. Analyses of H3K27ac marks demonstrate GLI2-mediated transcription regulation of stem cell niche signals such as Wnt ligand genes, through enhancers conserved between the stomach and intestine.
Project description:We demonstrate the conserved Hh-GLI2-mediated chromatin and transcriptional regulation of both stomach and intestinal stromal stem cell niche signals. Analyses of H3K27ac marks demonstrate GLI2-mediated transcription regulation of stem cell niche signals such as Wnt ligand genes, through enhancers conserved between the stomach and intestine.
Project description:Bone marrow (BM) stromal cells are important in the development and maintenance of cells of the immune system. Using single cell RNA sequencing, we here explore the functional and phenotypic heterogeneity of individual transcriptomes of 1,167 murine BM mesenchymal stromal cells. These cells exhibit a tremendous heterogeneity of gene expression, which precludes the identification of defined subpopulations. However, according to the expression of 108 genes involved in the communication of stromal cells with hematopoietic cells, we have identified 14 non-overlapping subpopulations, with distinct cytokine or chemokine gene expression signatures. With respect to the maintenance of subsets of immune memory cells by stromal cells, we identify distinct subpopulations expressing IL7, IL15 and Tnfsf13b. Together, this study provides a comprehensive dissection of the BM stromal heterogeneity at the single cell transcriptome level and provides a basis to understand their lifestyle and their role as organizers of niches for the long-term maintenance of immune cells.
Project description:We employed single-cell RNA sequencing to understand stromal changes in murine melanomas and draining lymph nodes at single cell resolution at different points of tumour development.
Project description:Gastrointestinal stromal tumors (GIST) are thought to derive from the interstitial cells of Cajal (ICC) or an ICC precursor. Oncogenic mutations of the receptor tyrosine kinase KIT are present in most GIST. KIT K642E was originally identified in sporadic GIST and later found in the germ line of a familial GIST. A mouse model of harboring a germline Kit K641E mutant was created to model familial GIST. The expression profile was investigated in the gastric antrum in the knock-in Kit K641E murine GIST model by microarray.
Project description:The origin of bone marrow stromal cells (BMSCs) is not completely understood. We have identified a rare population of cells with a transcriptional profile consistent with endothelial to mesenchymal transition (Endo-MT) in human fetal development. Therefore, we hypothesized that Endo-MT contributes to bone marrow niche formation in mammals. Here, we sought to determine whether Endo-MT cells could be identified in murine bone marrow during embryonic development. We isolated bone marrow and collagenased bone fraction from long bones of 9 fetuses at embryonic day 17 (E17) and FACS purified endothelial cells and BMSCs for single cell RNA sequencing.