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:Whereas the cellular basis of the hematopoietic stem cell (HSC) niche in the bone marrow has been characterized, the nature of the fetal liver (FL) niche is not yet elucidated. We show that Nestin+NG2+ pericytes associate with portal vessels, forming a niche promoting HSC expansion. Nestin+NG2+ cells and HSCs scale during development with the fractal branching patterns of portal vessels, tributaries of the umbilical vein. After closure of the umbilical inlet at birth, portal vessels undergo a transition from Neuropilin-1+Ephrin-B2+ artery to EphB4+ vein phenotype, associated with a loss of peri-portal Nestin+NG2+ cells and emigration of HSCs away from portal vessels. These data support a model in which HSCs are titrated against a peri-portal vascular niche with a fractal-like organization enabled by placental circulation. Characterization of the transcriptome of fetal liver and adult bone marrow niche using RNA-seq
Project description:Adult hematopoietic stem cells (HSCs) reside primarily in bone marrow. However, hematopoietic stresses such as myelofibrosis, anemia, pregnancy, infection or myeloablation can mobilize HSCs to the spleen and induce extramedullary hematopoiesis (EMH). While the bone marrow HSC niche has been studied intensively, the EMH niche has received little attention. Here, we systematically assessed the physiological sources of the key niche factors, SCF and CXCL12, in the mouse spleen after EMH induction by cyclophosphamide plus granulocyte colony-stimulating factor, blood loss, or pregnancy. In each case, Scf was expressed by endothelial cells and Tcf21+ stromal cells, primarily around sinusoids in red pulp, while Cxcl12 was expressed by a subset of Tcf21+ stromal cells. EMH induction markedly expanded the Scf-expressing endothelial cells and stromal cells by inducing proliferation. Most splenic HSCs were adjacent to Tcf21+ stromal cells in red pulp. Conditional deletion of Scf from spleen endothelial cells or Scf or Cxcl12 from Tcf21+ stromal cells severely reduced spleen EMH and reduced blood cell counts without affecting bone marrow hematopoiesis. Endothelial cells and Tcf21+ stromal cells thus create the splenic EMH niche, which is necessary for the physiological response to diverse hematopoietic stresses. Unfractionated spleen cells (2 replicates) and FACS-sorted VE-cadherein negative Scf-GFP positive cells (3 replicates)
Project description:We here show that the niche regulates the quality of the hematopoietic stem cells (HSCs) that are regenerated after transplantation. We find that a reduced level of Wnt5a in the niche regenerates dysfunctional HSCs, which do not successfully engraft secondary recipients. In particular, RNA sequencing shows a dysregulated Zeb1-associated gene expression of multiple genes involved in the small GTPase-dependent actin polymerization pathway. Misexpression of these genes results in reduced ability to direct polarized F-actin localization, leading to defects in adhesion, migratory behavior and homing to the bone marrow of secondary recipients. Our study further shows that the Wnt5a-haploinsufficient environment similarly affects BCR-ABLp185+ cells, which, in 42% of the studied recipients, fail to generate leukemia and, in the remaining cases, fail to transfer leukemia to secondary hosts. Thus, we show that Wnt5a in the niche is required to regenerate HSCs and leukemic cells with functional ability to rearrange the actin cytoskeleton which is required for successful engraftment. Overall design: Hematopoietic stem cells are regenerated in WT or Wnt5a-haploinsufficient niches. We profile LSK hematopoiteic stem cells after transplantation and three cell populations from the niche environment: endothelial cells (EC), osteoblastic cells (OBC), and mesenchymal cells (MSC)
Project description:To further identify gene expression signatures in the niche cells (CD45 negative) during proliferation of Hematopoietic stem cells (LSK), we employed mice whole genome (60K) microarray expression profiling as a discovery platform to identify the up-regulated and down-regulated genes of the niche. [Samples A-D] In this experiment a physiological stress model was created where the recipient mice were subjected to sub lethal radiation (700 CGy) following a transplantation of 30,000 LSK cells (HSCs). Bone marrow cells were isolated on day 0 (before transplantation) and day 10 (post transplantation of 30,000 LSK cells when maximum proliferation of HSCs was observed). Donor HSCs was sorted by FACS following RNA isolation and cDNA synthesis followed by single color global gene expression analysis. Agilent one-color experiment,Organism:Mouse, Agilent Whole Genome Mouse 8x60k (AMADID: 26986) , Labeling kit: Agilent Quick-Amp labeling Kit (p/n5190-0442)