Early gene expression in mouse hematopoietic stem cells induced by Thrombopoietin stimulation and irradiation
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE84195 | GEO | 2017/12/31
SECONDARY ACCESSION(S): PRJNA328265
REPOSITORIES: GEO
Similar Datasets
Project description:The haematopoietic cytokine thrombopoietin (Tpo) is the primary regulator of megakaryocyte and platelet numbers and is required for maintenance of the haematopoetic stem cell compartment. Tpo is a heavily glycosylated, hepatocyte-derived cytokine which functions by binding to its receptor (TpoR) on target cells and thereby activating intracellular signalling cascades that induce their proliferation and/or differentiation. In addition to its role in signal propagation, TpoR is expressed on the surface of platelets, where it contributes to regulation of Tpo levels by sequestering circulating cytokine. TpoR belongs to the homodimeric Class I cytokine receptor family but is unusual due to a duplication of the Cytokine binding Homology Region (CHR). Almost thirty years after initial discovery of TpoR, the structure of the human Tpo:TpoR interaction was recently reported. Here we determine the structure of extracellular portion of the murine Tpo:TpoR signalling complex using single particle cryo-EM. The structure reveals that Tpo:TpoR forms a largely symmetrical 1:2 complex. The cytokine cross-links the same site on the membrane-distal CHR of both receptor chains using opposing surfaces and with significantly different affinities. This orients the two membrane-proximal CHRs such that they contact one another adjacent to the plasma membrane. The potential cytokine-binding site in CHR2 is glycosylated and does not interact with Tpo. A large insertion in CHR1 that is unique to Tpo forms a partially structured loop that is disulphide bonded to CHR2 and, in one receptor chain, contacts cytokine. Biochemical analyses indicate that the glycosylated C-terminal domain of Tpo does not influence receptor binding. We demonstrate that the therapeutic TpoR agonist Romiplostim binds to the same site on the receptor as does cytokine. Our study characterises the Tpo/TpoR interaction structurally and biochemically to allow for the future development of potent TpoR agonists for therapeutic use.
2024-01-09 | PXD046926 | Pride
Project description:Notch signaling regulates cell-fate decisions in several developmental processes and cell functions. However, a role for Notch in hepatic thrombopoietin (TPO) production remains unclear. We noted thrombocytopenia in mice with hepatic Notch1 deficiency, and so investigated TPO production and other features of platelets in these mice. We found that the liver ultrastructure and hepatocyte function were comparable between control mice and Notch1-deficient mice. However, the Notch1-deficient mice had significantly lower plasma TPO and hepatic TPO mRNA levels, concomitant with lower numbers of platelets and impaired megakaryocyte differentiation and maturation, which were rescued by addition of exogenous TPO. Additionally, JAK2/STAT3 phosphorylation was significantly inhibited in Notch1-deficient hepatocytes, consistent with the RNA-seq analysis. JAK2/STAT3 phosphorylation and TPO production was also impaired in cultured Notch1-deficient hepatocytes after treatment with desialylated platelets. Consistently, hepatocyte-specific Notch1 deletion inhibited JAK2/STAT3 phosphorylation and hepatic TPO production induced by administration of desialylated platelets in vivo. Interestingly, Notch1 deficiency downregulated the expression of HES5 but not HES1. Moreover, desialylated platelets promoted the binding of HES5 to JAK2/STAT3, leading to JAK2/STAT3 phosphorylation and pathway activation in hepatocytes. Hepatocyte Ashwell-Morell receptor (AMR) (asialoglycoprotein receptor 1, ASGR1) physically associates with Notch1 and inhibition of AMR impaired Notch1 signaling activation and hepatic TPO production. Furthermore, blockage of Dll4 on desialylated platelets inhibited hepatocyte Notch1 activation and HES5 expression, JAK2/STAT3 phosphorylation and subsequent TPO production. In conclusion, our study identifies a novel regulatory role of Notch1 in hepatic TPO production, indicating that it might be a target for modulating TPO level.
2024-04-12 | GSE250529 | GEO
Project description:Thrombopoietin (TPO) and its receptor MPL play crucial roles in hematopoietic stem cell (HSC) function and platelet production. However, the precise effects of TPO/MPL signaling on HSC regulation in different hematopoietic niches remain unclear. Here, we investigated the effects of TPO/MPL ablation on marrow and splenic hematopoiesis in TPO-/- and MPL-/- mice during aging. Despite severe thrombocytopenia, TPO-/- and MPL-/- mice did not develop marrow failure during a 2-year follow-up. Marrow and splenic HSCs exhibited different responses to TPO/MPL ablation and exogenous TPO treatment. Splenic niche cells compensated for marrow HSC loss in TPO-/- and MPL-/- mice by upregulating CXCL12 levels. These findings provide new insights into the complex regulation of HSCs by TPO/MPL and reveal a previously unknown link between TPO and CXCL12, two key growth factors for HSC maintenance. Understanding the distinct regulatory mechanisms between marrow and spleen hematopoiesis will help develop novel therapeutic approaches for hematopoietic disorders.
2023-12-16 | GSE249912 | GEO
Project description:Thrombopoietin (TPO) is a critical cytokine regulating hematopoietic stem cell maintenance and differentiation into the megakaryocytic lineage. However, the transcriptional and chromatin dynamics elicited by TPO signaling are poorly understood. Here, we study the immediate early transcriptional and cis-regulatory responses to TPO in hematopoietic stem/progenitor cells (HSPCs) and use this paradigm of cytokine signaling to chromatin to dissect the relation between cis-regulatory activity and chromatin architecture. We show that TPO profoundly alters the transcriptome of HSPCs, with key hematopoietic regulators being transcriptionally repressed within 30 minutes of TPO. By examining cis-regulatory dynamics and chromatin architectures, we demonstrate that these changes are accompanied by rapid and extensive epigenome remodeling of cis-regulatory landscapes that is spatially coordinated within topologically associating domains (TADs). Moreover, homotypic TPO-responsive enhancers are spatially clustered and engage in preferential intra- and inter-TAD interactions that are only moderately perturbed by TPO signaling. By further examining the link between cis-regulatory dynamics and chromatin looping, we show that rapid modulation of cis-regulatory activity is largely independent of chromatin looping dynamics. Finally, we show that activated and repressed cis-regulatory elements share a remarkably similar DNA sequence composition and that in vivo transcription factor binding patterns accurately predict rapid cis-regulatory responses to TPO.
2018-01-25 | GSE100835 | GEO
Project description:Radiation-induced lung injury (RILI) initiates radiation pneumonitis and progresses to fibrosis as the main side effect of lung cancer patients treated with radiotherapy. There is no effective drug for RILI. Sustained vascular activation is a major contributor to the establishment of chronic disease. Here, using a whole thoracic irradiation (WTI) mouse model, we investigated the mechanisms and effectiveness of thrombopoietin mimetic (TPOm) for preventing RILI. We demonstrated that administering TPOm 24 hours before irradiation decreased histologic lung injury score, apoptosis, vascular permeability, expression of pro-inflammatory cytokines, and neutrophil infiltration in the lung of mice 2 weeks after WTI. We described the expression of c-MPL, a TPO receptor, in mouse primary pulmonary microvascular endothelial cells, showing TPOm reduced endothelial cell-neutrophil adhesion by inhibiting ICAM-1 expression. Seven months after WTI, TPOm-treated lung exhibited less collagen deposition, expression of MMP-9, TIMP-1, IL-6, TGF-b, and p21. Moreover, TPOm improved lung vascular structure, lung density, and respiration rate, leading to a prolonged survival time after WTI. Single-cell RNA sequencing analysis of lungs 2 weeks after WTI revealed that TPOm shifted populations of capillary endothelial cells towards a less activated and more homeostatic phenotype. Taken together, TPOm is protective for RILI by inhibiting endothelial cell activation.
2024-08-01 | GSE273235 | GEO
Project description:Romiplostim, a thrombopoietin (TPO) receptor agonist, is a clinically approved drug that is clearly effective in reconstituting hematopoiesis in refractory aplastic anemia and idiopathic thrombocytopenic purpura. However, the mechanism underlying its biological effect is unknown, and its difference with other TPO receptor agonists remains unclear. Therefore, we determined the in vitro expansion effect of romiplostim on human CD34+ hematopoietic stem and progenitor cells (HSPCs) versus recombinant human TPO (rhTPO) and another clinically available drug eltrombopag. We also performed single-cell RNA-seq to define the effect of romiplostim on CD34+ HSPCs at the molecular level. The maximum expansion effect of romiplostim on total CD34+ cells, CD34+CD38+ progenitor cells, and CD34+CD38− immature cells was comparable to that of rhTPO, but higher than that of eltrombopag, particularly on CD34+CD38− immature cells. Single-cell RNA-seq analysis revealed that both romiplostim and eltrombopag induced signatures driven by rhTPO, but romiplostim induced molecular changes related to RHOA signaling at the most primitive subsets in HSPCs that were partially or not driven by eltrombopag. Additionally, romiplostim lacked the ability to induce TFRC expression observed by eltrombopag. In conclusion, romiplostim expands and affects human HSPCs similar to rhTPO but partially different from eltrombopag in terms of induction of gene expression.
2024-09-24 | GSE253936 | GEO
Project description:Small molecular TPO mimetics, LGD-4665 and eltrombopag, were efficacious in stimulating the formation of CD41+ cells from human bone marrow CD34+ cells. To better understand the mechanism of action of TPO mimetics, a microarray study was performed to compare global gene expression in CD34+ cells induced by small molecular TPO mimetics eltrombopag and LGD4665, to changes in response to recombinant human thrombopoietin (TPO). Keywords: Drug Treatment
2019-03-24 | GSE12968 | GEO
Project description:Dnm2fl/fl Pf4-Cre (Dnm2Plt-/-) mice lacking the endocytic GTPase dynamin 2 (DNM2) in platelets and megakaryocytes (MKs) develop hallmarks of myelofibrosis. At the cellular level, the tyrosine kinase JAK2 is constitutively active but decreased in expression in Dnm2Plt-/- platelets. Additionally, Dnm2Plt-/- platelets cannot endocytose the thrombopoietin (TPO) receptor Mpl, leading to elevated circulating TPO levels. Here, we assessed whether the hyperproliferative phenotype of Dnm2Plt-/- mice was due to JAK2 constitutive activation or elevated circulating TPO levels. In unstimulated Dnm2Plt-/- platelets, STAT3 and to a lower extent STAT5 were phosphorylated, but their phosphorylation was slowed and diminished upon TPO stimulation. We further crossed Dnm2Plt-/- mice in the Mpl-/- background to generate Mpl-/- Dnm2Plt-/- mice lacking Mpl ubiquitously and DNM2 in platelets and MKs. Mpl-/- Dnm2Plt-/- platelets had severely reduced JAK2 and STAT3 but normal STAT5 expression. Mpl-/- Dnm2Plt-/- mice had severely reduced bone marrow MK and hematopoietic stem and progenitor cell numbers. Additionally, Mpl-/- Dnm2Plt-/- mice had severe erythroblast maturation defects, decreased expression of hemoglobin and heme homeostasis genes, increased expression of ribosome biogenesis and protein translation genes, and developed anemia with grossly elevated plasma erythropoietin levels, leading to early fatality by postnatal day 25. Mpl-/- Dnm2Plt+/+ mice had impaired EB development at three weeks of age, which normalized with adulthood. Together, the data shows that DNM2-dependent Mpl-mediated endocytosis in platelets and MKs is required for steady-state hematopoiesis and provides novel insights into a developmentally controlled role for Mpl in normal erythropoiesis, regulating hemoglobin and heme production.
2022-08-25 | GSE206343 | GEO
Project description:In order to examine the mechanism of TPO on cardiac protection against myocardial infarction damage (MI), we have employed whole genome microarray expression profiling as a discovery platform to identify genes with the potential to delineate the TPO cardioprotective mechanism against infarction. MI and TPO induced gene expressions in rat heart were measured at week 4. Two biological replicates were performed for each treatment group.
2012-12-01 | E-GEOD-22489 | biostudies-arrayexpress
Project description:Class I cytokine receptors such as Thrombopoietin receptor (MPL) are dimers, but it is unclear whether remodeling receptor dimer topology is a viable strategy to "tune" signaling output. We utilized diabodies (DA) as surrogate ligands in a prototypical dimeric receptor-ligand system, the cytokine Thrombopoietin (TPO) and its receptor (TpoR), to dimerize TpoR ectodomains in non-native architectures. Diabody-induced signaling amplitudes varied from full to minimal agonism. Here we describe a single-cell transcriptome analysis of 659 human Hematopoietic Stem Cells cultured with different DA. We find several difference between differentiation and activation of signaling pathways compared to TPO.
2021-02-01 | GSE115235 | GEO