Inhibiting the P2Y12 Receptor in Megakaryocytes and Platelets Suppresses Interferon-Associated Responses
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE242369 | GEO | 2025/05/07
REPOSITORIES: GEO
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Project description:d9 and d12 Mks were either cultured statically or subjected to shear flow for 30 min; at d9, half the Mks were placed back in culture for 30 min (60 min time point) Megakaryocytes (Mks) are exposed to shear flow as they migrate from the bone marrow hematopoietic compartment into circulation thus releasing platelets and pro/preplatelets directly into the blood stream. Shear forces have been now established as promoting Mk maturation and platelet biogenesis. In order to understand the underlying mechanisms that modulate the response of Mks to shear forces, we carried out transcriptional analysis on immature and mature stem cell-derived Mks that were exposed to physiologically-relevant shear (2.5 dyn/cm2). In immature (d9) Mks, shear exposure upregulated genes related to growth and Mk maturation, while in mature (d12) Mks, it upregulated genes involved in apoptosis and intracellular transport. Following shear-flow exposure, 6 AP-1 transcripts (ATF4, JUNB, JUN, FOSB, FOS, and JUND) were upregulated at d9 and two AP-1 proteins (JunD and c-Fos) were upregulated both at d9 and d12. Our data show that MAPK signaling is linked to both the shear-stress response and AP-1 upregulation. JNK phosphorylation increased significantly following shear stimulation, while JNK inhibition reduced shear-induced JunD protein expression. Although p38 phosphorylation did not increase following shear flow, its inhibition reduced shear-induced JunD and c-Fos protein expression. JNK inhibition reduced fibrinogen binding of d9 and d12 platelet-like particle s (PLPs) and P-selectin expression at d12 PLPs, while p38 inhibition reduced fibrinogen binding of d12 PLPs. Here we show that mechanotransduction of shear forces in Mks results in JNK activation, AP-1 upregulation, and downstream transcriptional changes that promote maturation of immature Mks and platelet biogenesis in mature Mks. Two- and Three-condition experiment (flow vs. static culture condition, d9 vs. d12, and 30 min vs. 60 min at d9); Biological replicates: 3; Technical replicates: 1 (dye-swap)
2016-02-01 | E-GEOD-75766 | biostudies-arrayexpress
Project description:Platelet homeostasis is essential for vascular integrity and immune defense. While the process of platelet formation by fragmenting megakaryocytes (thrombopoiesis) has been extensively studied, the cellular and molecular mechanisms required to constantly replenish the pool of megakaryocytes (MKs) by their progenitor cells (megakaryopoiesis) remains unclear. Here we use intravital imaging to track the cellular dynamics of megakaryopoiesis over days. We identify plasmacytoid dendritic cells (pDCs) as homeostatic sensors that monitor the bone marrow for apoptotic MKs and deliver IFN- to the MK niche triggering local on-demand proliferation and maturation of MK progenitors. This fine-tuned coordination between thrombopoiesis and megakaryopoiesis is crucial for MK and platelet homeostasis in steady state and stress. However, excessive activation of pDCs, such as by viral infections, can disturb this homeostatic circuit. Accordingly, we show that pDCs activated by SARS-CoV2 drive inappropriate megakaryopoiesis. Together, we uncover a hitherto unknown pDC-dependent homeostatic circuit that involves innate immune sensing and demand-adapted release of inflammatory mediators to maintain tissue homeostasis of the megakaryocytic lineage.
2024-05-01 | GSE261996 | GEO
Project description:Human embryonic stem cells (hESCs) have become an ideal cell source for the ex vivo generation of megakaryocyte (MK) and platelet products for clinical applications. However, an ongoing challenge is to establish scalable culture systems to maximize the yield of stem cell-derived MKs that release platelets. We defined a specific dynamic 3D manufacturing system that could remarkably facilitate megakaryopoiesis and increase the yield of platelet-producing MKs from hESCs within a 12-day induction period. Additionally, an increased number of > 16N ploidy MKs, proplatelets, and platelets were generated from induced cells harvested on day 12 using the specific dynamic culture method. The specific dynamic culture method significantly enhanced endothelium-to-hematopoietic transition and early hematopoiesis. More importantly, MK fate was significantly facilitated in a specific dynamic manner during early hematopoiesis. Mechanistically, this dynamic culture significantly enhanced mitochondrial function via the oxidative phosphorylation pathway and caused differentiation skewing of hESCs toward megakaryopoiesis. We defined a specific dynamic culture system in a baffled-flow manner that enabled the mass production of MKs from hESCs within 12 days. This study can aid in the automatic and scalable production of MKs from stem cells using baffled-flow bioreactors and assist in the manufacturing of hESC-derived MK and platelet products.
2023-12-14 | GSE228163 | GEO
Project description:d9 and d12 Mks were either cultured statically or subjected to shear flow for 30 min; at d9, half the Mks were placed back in culture for 30 min (60 min time point) Megakaryocytes (Mks) are exposed to shear flow as they migrate from the bone marrow hematopoietic compartment into circulation thus releasing platelets and pro/preplatelets directly into the blood stream. Shear forces have been now established as promoting Mk maturation and platelet biogenesis. In order to understand the underlying mechanisms that modulate the response of Mks to shear forces, we carried out transcriptional analysis on immature and mature stem cell-derived Mks that were exposed to physiologically-relevant shear (2.5 dyn/cm2). In immature (d9) Mks, shear exposure upregulated genes related to growth and Mk maturation, while in mature (d12) Mks, it upregulated genes involved in apoptosis and intracellular transport. Following shear-flow exposure, 6 AP-1 transcripts (ATF4, JUNB, JUN, FOSB, FOS, and JUND) were upregulated at d9 and two AP-1 proteins (JunD and c-Fos) were upregulated both at d9 and d12. Our data show that MAPK signaling is linked to both the shear-stress response and AP-1 upregulation. JNK phosphorylation increased significantly following shear stimulation, while JNK inhibition reduced shear-induced JunD protein expression. Although p38 phosphorylation did not increase following shear flow, its inhibition reduced shear-induced JunD and c-Fos protein expression. JNK inhibition reduced fibrinogen binding of d9 and d12 platelet-like particle s (PLPs) and P-selectin expression at d12 PLPs, while p38 inhibition reduced fibrinogen binding of d12 PLPs. Here we show that mechanotransduction of shear forces in Mks results in JNK activation, AP-1 upregulation, and downstream transcriptional changes that promote maturation of immature Mks and platelet biogenesis in mature Mks.
2016-02-01 | GSE75766 | GEO
Project description:Platelets are anucleated blood cells that are produced by their progenitor cell, the megakaryocyte (MK). Platelets are centrally positioned in hemostasis and thrombosis and, according to the recent findings, play key roles in innate immunity, inflammation, atherogenesis, and cancer metastasis. The quantitative and qualitative properties of platelets are crucial determinants of their hemostatic function. While the regulatory mechanisms of platelet number and size have been studied separately, critical questions remain regarding the interplay of platelet number and size in hemostasis. In this study, using a mouse model of irradiation (IR)-induced thrombocytopenia, we show that mature MKs (mMKs) are resistant to IR and maintain the nadir platelet levels post IR. To identify the phenotype switching and function variation in BM MKs post IR, we performed microarray expression profiling of MKs from the bone marrow of mice at 1- or 3-days post IR and control mice (Ctrl).
2023-12-27 | GSE222512 | GEO
Project description:We have published a novel method for the large-scale in vitro generation of megakaryocytes (MKs), the blood platelet precursors, by applying a transcription factor (TF) driven forward programming strategy to human pluripotent stem cells (hPSCs). We have demonstrated that the concurrent expression of GATA1, FLI1 and TAL1 in hPSCs and chemically defined culture conditions with minimal supportive cytokines produce highly pure MK cultures with long-term growth and release of functional platelets. Unravelling the molecular mechanisms underlying MK forward programming will bring biological insights that shall lead to improvements of the MK programming technology. Particularly, we have been focusing on the characterisation of the MK progenitor that allows long-term expansion of pure MK cultures, which is a key asset of the method. Using single cell RNA sequencing of long-term cultures, we have started to identify and functionally confirmed surface markers of the MK progenitor.
2018-10-23 | GSE121579 | GEO
Project description:Characterize the genes regulated by MKL1/SRF complex in human megakaryocytes (MKs) derived from cord blood or cytapheresis : Using a knock down approach by small interference of MKL1 in MK progenitors, we observed a decrease in the percentage of cells with actin polymerization after adhesion on various substrates, an increase of mean ploidy level and apoptosis. Furthermore, MKL1 inhibition induced a major defect in pro-platelet formation and MKs migration. These results clearly demonstrate that MKL1 is involved in the cytoskeleton organization and maturation of MKs as well as in platelet formation. The goal of gene profiling was to identify new potential MKL1/SRF targets the expression level of which was down regulated after MKL1 inhibition: Human CD34+ cells isolated from cord blood or cytapheresis were transduced by a control lentivirus (designed as SCR; scramble) or by the lentivirus encoding for shRNA of MKL1 (designed as shMKL1) both containing a GFP expressed under the control of PGK promoter. The cells were than grown in serum free medium supplemented by thrombopoietin leading to a generation of megakaryocytes. At day 9 of culture (80% of MKs), the GFP positive cells were sorted, RNAs were extracted and submitted to hybridization as described in annex protocols. Two lists of genes (one for cord blood samples and one for cytapheresis samples) deregulated after the repression of MKL1 were done comparing the intensity of hybridization between SCR and shMKL1 samples. The common list of genes deregulated in MKs from cord blood and cytapheresis after the repression of MKL1 was than generated.
2009-09-14 | E-TABM-640 | biostudies-arrayexpress
Project description:Megakaryocyte (MK) differentiation is well described in morphologic terms but its molecular counterparts and the basis for platelet release are incompletely understood. We profiled mRNA expression in populations of primary mouse MKs representing successive differentiation stages. Genes associated with DNA replication are highly expressed in young MKs, in parallel with endomitosis. Intermediate stages are characterized by disproportionate expression of genes associated with the cytoskeleton, cell migration and G-protein signaling, whereas terminally mature MKs accumulate hemostatic factors, including many membrane proteins. We used these expression profiles to extract a reliable panel of molecular markers for MKs of early, intermediate or advanced differentiation, and establish its value using mouse models of defective thrombopoiesis resulting from absence of GATA-1, NF-E2 or tubulinß1. Computational analysis of the promoters of late-expressed MK genes identified new candidate targets for NF-E2, a critical transcriptional regulator of platelet release. One such gene encodes the kinase adaptor protein LIMS1/PINCH1, which is highly expressed in MKs and platelets and significantly reduced in NF-E2-deficient cells. Transactivation studies and chromatin immunoprecipitation implicate Lims1 as a direct target of NF-E2 regulation. Attribution of stagespecific genes, in combination with various applications, thus constitutes a powerful way to study MK differentiation and platelet biogenesis Experiment Overall Design: MK progenitors expand in mouse bone marrow or fetal liver cell preparations cultured with thrombopoietin, and mature over 5-6 days in vitro. After 3 days of culture, a significant fraction of cells shows features of committed MK progenitors, and numerous terminally mature, proplatelet-forming MKs appear by day 5. Because isolation of cell populations that correspond to sequential stages in MK differentiation is hindered by the lack of synchrony in primary MK cultures, we applied flow cytometry to harvest sub-populations that are substantially enriched for MKs with defined properties. High surface expression of the lineage marker CD41 identified MKs, whereas forward-scatter (FSC) properties distinguished cells on the basis of size. We collected thrombopoietic culture suspensions from days 3, 4 and 6, and sorted populations by flow cytometry. RNAs were prepared from sorted cells to probe Affymetrix MOE430A mouse oligonucleotide arrays.
2008-11-07 | E-GEOD-6593 | biostudies-arrayexpress
Project description:Antiplatelet therapy is the most important treatment to reduce the risk of developing recurrent thrombosis, and to prevent progression to a complete occlusion of coronary arterial disease (CAD) patients after percutaneous coronary intervention Aim of study was to investigate the relationship between response to antiplatelet drugs and global mRNA gene expression in peripheral blood cells (PBC) in patients with coronary arterial disease (CAD) All patients were treated crhonically with acetylsalicylic acid (ASA) (100 mg/day) and clopidogrel (75 mg/day). Blood samples were drown before PCI to evaluate platelet reactivity by VerifyNow® ASA and P2Y12 assays and mRNA expression was measured by Affymetrix GeneChip Human Exon 1.0 ST array.
2012-09-15 | E-GEOD-32226 | biostudies-arrayexpress
Project description:Here, using single-cell sequencing we identified an MK derived immunoregulatory cell population, which plays an important role in host-protective responses against bacteria. In contrast to platelet-generating MKs, MK derived immunoregulatory cells highly express immune response genes and chemokines.
2022-03-24 | GSE168224 | GEO