Project description:Primary intestinal epithelial cells were isolated from the proximal part of the small intestine from either E16.5 foetal tissue or adult tissue and embedded in matrigel for culturing in in advanced F12/DMEM supplemented with EGF, R-spondin and Noggin. RNA was extracted from cultures established from independent animals and subjected to expression profiling.
Project description:Long-term tissue homeostasis is governed by balanced contribution from adult stem cells. We recently identified Lrig1 as a marker of stem cells in mouse epidermis. Here, we show that Lrig1 expressing cells are molecularly and functionally distinct from previously characterized epidermal stem cell populations. During steady state homeostasis, Lrig1 expressing cells are responsible for the maintenance of the uppermost compartment of the pilosebaceous unit known as the infundibulum. Lineage tracing demonstrates that the epidermis is divided into discrete compartments during homeostasis, each maintained by its own resident stem cells. Compartment boundaries are rapidly broken when stem cell progeny are recruited to sites of injury, where they subsequently change behavior according to the environment. Oncogene activation in Lrig1 expressing cells alters proliferation but auxiliary stimuli are required for rapid tumor growth. Our data demonstrate that stem cell niches are compartmentalized according to altering requirements for tissue replenishment.
Project description:Beta-catenin signaling is required for establishment of leukemic stem cells (LSCs) in acute myeloid leukemia (AML), yet the upstream regulators that can augment this pathway are unknown. Through genome-wide gene expression analysis and functional studies, we identified an important role for GPR84 in MLL AML. Suppression of GPR84 significantly inhibited cell growth in pre-LSCs, reduced LSC frequency and impaired reconstitution of MLL AML. Furthermore, GPR84 conferred a growth advantage to Hoxa9/Meis1a transduced hematopoietic stem cells (HSCs). Our microarray analysis demonstrated that GPR84 overexpression significantly up-regulated a small set of MLL-fusion targets and beta-catenin co-effectors, and down-regulated a hematopoietic cell cycle inhibitor. These data thus reveal a previously unrecognized role of GPR84 in the maintenance of fully developed AML by sustaining aberrant beta-catenin signaling in LSCs. HSC-derived Hoxa9/Meis1a pre-LSCs were transduced with GPR84 cDNA or empty vector, and replated in methylcellulose supplemented with cytokines. Each group contains triplicate samples.
Project description:Transcriptional profiling of hESCs differentiated towards an endodermal fate in chemically-defined media (3 days) compared to clones subjected to EOMES knockdown (via shRNA) under the same conditions.
Project description:Transcriptional profiling of hESCs in chemically-defined culture media compared to hESCs differentiated for 36h in the additional presence of FGF, LY294002 and either BMP or ActivinA.