Project description:We used microarrays to investigate gene expression changes in tumor-bearing Sca1-TOMATO-Lmo2 Nu/Nu mice Tumor-bearing bone marrows of three Sca1-TOMATO-Lmo2 Nu/Nu mice compared with bone marrow cells from four Control Nude mice and with thymus leukemic cells from ten Sca1-TOMATO-Lmo2 mice. GSM2209767 - GSM2209776 are re-analyses of GSE83570 (GSM2209749 - GSM220975 and GSM2209757 - GSM2209759).
Project description:We used microarrays to investigate gene expression changes in tumor-bearing Sca1-TOMATO-Lmo2 mice and in preleukemic cells from Sca1-TOMATO-Lmo2 mice. Tumor-bearing thymus of eleven Sca1-TOMATO-Lmo2 mice compared with thymus cells from 4 WT mice, with TOMATO-positive thymus preleukemic T cells from 5 Sca1-TOMATO-Lmo2 mice and with TOMATO-negative thymus preleukemic T cells from 5 Sca1-TOMATO-Lmo2 mice GSM2209749 - GSM220975 and GSM2209757 - GSM2209759 were re-analyzed by GSE83571 (GSM2209767 - GSM2209776).
Project description:We used microarrays to investigate gene expression changes in tumor-bearing Sca1-TOMATO-Lmo2 mice and in preleukemic cells from Sca1-TOMATO-Lmo2 mice.
Project description:Maintenance of hematopoietic stem cells (HSCs) in vitro has been believed to be difficult due to a lack of complete understanding of HSC quiescence maintained by the niche. Recent evidence suggests that in vitro maintenance of human and mouse long-term HSCs (LT-HSCs) is possible through dual inhibition (2i) of both GSK-3 and mTOR in the absence of cytokines, serum, or feeder cells.
Project description:The thymic stroma supports T lymphocyte development and consists of an epithelium maintained by thymic epithelial progenitors. The molecular pathways that govern epithelial homeostasis are poorly understood. Here we demonstrate that deletion of Rac1 in Keratin 5/Keratin 14 expressing embryonic and adult thymic epithelial cells leads to loss of the thymic epithelial compartment. Rac1 deletion led to an increase in c-Myc expression and a generalized increase in apoptosis associated with a decrease in thymic epithelial proliferation. Our results suggest Rac1 maintains the epithelial population, and equilibrium between Rac1 and c-Myc may control proliferation, apoptosis and maturation of the thymic epithelial compartment. Understanding thymic epithelial maintenance is a step toward the dual goals of in vitro thymic epithelial cell culture and T cell differentiation, and the clinical repair of thymic damage from graft-versus-host-disease, chemotherapy or irradiation.
Project description:Reactive oxygen species (ROS) represent a by-product of metabolism and their excess is toxic for hematopoietic stem and progenitor cells (HSPCs). During embryogenesis, a small number of HSPCs are produced from the hemogenic endothelium, before they colonize a transient organ where they expand, for example the fetal liver in mammals. In this study, we use zebrafish to understand the molecular mechanisms that are important in the caudal hematopoietic tissue (equivalent to the mammalian fetal liver) to promote HSPC expansion. High levels of ROS are deleterious for HSPCs in this niche, however this is rescued by addition of antioxidants. We show that Cx41.8 is important to lower ROS levels in HSPCs. We also demonstrate a new role for ifi30, known to be involved in the immune response. In the hematopoietic niche, Ifi30 can recycle oxidized glutathione to allow HSPCs to dampen their levels of ROS, a role that could be conserved in human fetal liver.
Project description:The thymus represents the "cradle" for T cell development, with thymic stroma providing multiple soluble and membrane cues to developing thymocytes. Although IL-7 is recognized as an essential factor for thymopoiesis, the "environmental niche" of thymic IL-7 activity remains poorly characterized in vivo. Using bacterial artificial chromosome transgenic mice in which YFP is under control of IL-7 promoter, we identify a subset of thymic epithelial cells (TECs) that co-express YFP and high levels of Il7 transcripts (IL-7(hi) cells). IL-7(hi) TECs arise during early fetal development, persist throughout life, and co-express homeostatic chemokines (Ccl19, Ccl25, Cxcl12) and cytokines (Il15) that are critical for normal thymopoiesis. In the adult thymus, IL-7(hi) cells localize to the cortico-medullary junction and display traits of both cortical and medullary TECs. Interestingly, the frequency of IL-7(hi) cells decreases with age, suggesting a mechanism for the age-related thymic involution that is associated with declining IL-7 levels. Our temporal-spatial analysis of IL-7-producing cells in the thymus in vivo suggests that thymic IL-7 levels are dynamically regulated under distinct physiological conditions. This IL-7 reporter mouse provides a valuable tool to further dissect the mechanisms that govern thymic IL-7 expression in vivo.