Early gene expression in mouse hematopoietic stem cells induced by Thrombopoietin stimulation and irradiation
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE84195 | GEO | 2017/12/31
SECONDARY ACCESSION(S): PRJNA328265
REPOSITORIES: GEO
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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: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) 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:To determine the molecules involved in beta3 integrin signaling in HSCs, we carried out DNA microarray analyses using HSCs stimulated with ligand-mimic antibody for intetegrin beta3 in the presence of stem cell factor(SCF) and/or thrombopoietin (TPO). All experiments were performed in duplicate or triplicate using sorted cells that were independently prepared in separate experiments.
2011-11-16 | GSE33696 | GEO
Project description:To determine the molecules involved in beta3 integrin signaling in HSCs, we carried out DNA microarray analyses using HSCs stimulated with ligand-mimic antibody for intetegrin beta3 in the presence of stem cell factor(SCF) and/or thrombopoietin (TPO). All experiments were performed in duplicate or triplicate using sorted cells that were independently prepared in separate experiments. After CD34-KSL HSCs were cultured with 2C9.G2 or control IgG for 5 days in S-Clone SF-03 medium supplemented with 50 ng/ml SCF and/or 50 ng/ml TPO, gene expression profiles were examimed using 5,000 sorted CD48-KSL cells from each sample.
2011-11-16 | E-GEOD-33696 | biostudies-arrayexpress
Project description:Eltrombopag, a small molecule thrombopoietin receptor (TPO-R) agonist and potent intracellular iron chelator, has shown remarkable efficacy to stimulate sustained multilineage hematopoiesis in patients with bone marrow failure syndromes, suggesting an effect at the most immature hematopoietic stem and multipotent progenitor level. While the functional and molecular effects of Eltrombopag on megakaryopoiesis have been carefully studied in the recent past, insights into its mechanistic impact on the earliest stages of hematopoiesis have been limited. Additionally, previous studies also revealed molecular pathway of Eltrombopag apart from stimulation of TPO signaling, detail characterization remains to be addressed. In this study, we investigated the effects of Eltrombopag, in comparison with TPO, on highly-purified primary hematopoietic stem cells (HSCs) from healthy human donors. The binding of Eltrombopag to TPO-R is species-specific to human and primate cells. we also utilized HSCs isolated mouse as separation-of-function models to directly assess the molecular effect of Eltrombopag on HSCs independent of TPOR stimulation.
2018-09-17 | GSE107429 | GEO
Project description:Eltrombopag, a small molecule thrombopoietin receptor (TPO-R) agonist and potent intracellular iron chelator, has shown remarkable efficacy to stimulate sustained multilineage hematopoiesis in patients with bone marrow failure syndromes, suggesting an effect at the most immature hematopoietic stem and multipotent progenitor level. While the functional and molecular effects of Eltrombopag on megakaryopoiesis have been carefully studied in the recent past, insights into its mechanistic impact on the earliest stages of hematopoiesis have been limited. Additionally, previous studies also revealed molecular pathway of Eltrombopag apart from stimulation of TPO signaling, detail characterization remains to be addressed. In this study, we investigated the effects of Eltrombopag, in comparison with TPO, on highly-purified primary hematopoietic stem cells (HSCs) from healthy human donors. The binding of Eltrombopag to TPO-R is species-specific to human and primate cells. we also utilized HSCs isolated mouse as separation-of-function models to directly assess the molecular effect of Eltrombopag on HSCs independent of TPOR stimulation.
2018-09-17 | GSE107428 | 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:Thrombopoietin (TPO), acting through its receptor Mpl, has two major physiological roles: ensuring production of sufficient platelets via stimulation of megakaryocyte production, and maintaining hematopoietic stem cell (HSC) quiescence. Mpl also controls circulating TPO concentration via receptor-mediated internalisation and degradation. We demonstrate that the megakaryocytosis and increased platelet mass in mice with mutations in the Myb or p300 genes causes reduced circulating TPO concentration and TPO starvation of the stem cell compartment, which is exacerbated because these cells additionally exhibit impaired responsiveness to TPO. Total RNA obtained from bone marrow Lineage- Sca-1+ c-Kit+ cells of mice that were mutant or knocked out for Myb, p300 or Mpl were compared to wild type samples. We have found that HSCs from MybPlt4/Plt4 and p300Plt6/Plt6 mice show altered expression of TPO-responsive genes, suggesting that TPO starvation is an important factor in the hematopoietic phenotypes observed in these mice .
2011-01-31 | E-TABM-1050 | biostudies-arrayexpress