Project description:We performed genome-wide profiling of oligodendrocyte lineage transcription factor 2 (Olig2) and other histone markers in platelet-derived growth factor subunit B (PDGFB)-induced glioma and genome-occupancy analyses coupled with transcriptome profiling to reveal gene regulatory network. Examination of Olig2, H327Ac, and H3K4me3 genome-wide occupancy in PDGFB-induced Ctrl-T and Olig2cKO brain tumors (gliomas).
Project description:The aim of this study is to identify candidate genes modulating platelet reactivity in aspirin-treated cardiovascular patients using an integrative network-based approach. Platelet reactivity was assessed in 110 cardiovascular patients treated with aspirin 100mg/d by aggregometry using several agonists. Patients with extreme high or low PR were selected for further analysis. Data derived from quantitative proteomic of platelets and platelet sub-cellular fractions, as well as from transcriptomic analysis were integrated with a network biology approach.
Project description:Platelet reactivity (PR) in cardiovascular (CV) patients is variable between individuals and modulates clinical outcome. However, the determinants of platelet reactivity are largely unknown. Integration of data derived from high-throughput omics technologies may yield novel insights into the molecular mechanisms that govern platelet reactivity. The aim of this study was to identify candidate genes modulating platelet reactivity in aspirin-treated cardiovascular patients PR was assessed in 110 CV patients treated with aspirin 100mg/d by aggregometry using several agonists. 12 CV patients with extreme high or low PR were selected for transcriptomics, proteomics and miRNA analysis.
Project description:To identify if platelet activation would result in altered platelet miRNA profile, not only in total RNA sample, also in AGO2-immunoprecipitation(AGO2-IP) products. To determinate if altered platelet miRNAs could regulate de novo protein synthesis of angiogenic factors in activated platelets, and even more importantly, if miRNA-regulated platelet angiogenic factor synthesis could result in changes of platelet angiogenic activities.
Project description:Cyclic thrombocytopenia (CTP) is a rare disease of characterized by periodic platelet count oscillations of uncertain etiology. As part of a study that applied systems biology approaches to investigate two patients with CTP, we performed whole blood transcriptome analyses on semi-weekly collected sequential samples covering two platelet cycles. This blood transcriptome analysis revealed cyclical gene expression changes of platelet-specific genes that are in parallel with, and leading platelet count oscillations in both patients. In addition, erythrocyte-specific genes and neutrophil-specific genes also exhibited cyclic patterns which preceded platelet-specific genes. These findings revealed cyclical trilineage hematopoiesis, most pronounced in megakaryopoiesis in both patients with CTP.
Project description:MicroRNAs (miRNAs) regulate cell physiology by altering protein expression, but the biology of platelet miRNAs is largely unexplored. We tested whether platelet miRNA levels were associated with platelet reactivity by genome-wide profiling using platelet RNA from 19 healthy subjects. We found that human platelets express 284 miRNAs. Unsupervised hierarchical clustering of miRNA profiles resulted in 2 groups of subjects that appeared to cluster by platelet aggregation phenotypes. Seventy-four miRNAs were differentially expressed (DE) between subjects grouped according to platelet aggregation to epinephrine, a subset of which predicted the platelet reactivity response. Using whole genome mRNA expression data on these same subjects, we computationally generated a high-priority list of miRNA-mRNA pairs in which the DE platelet miRNAs had binding sites in 3'UTRs of DE mRNAs, and the levels were negatively correlated. Three miRNA-mRNA pairs (miR-200b:PRKAR2B, miR-495:KLHL5 and miR-107:CLOCK) were selected from this list and all 3 miRNAs knocked down protein expression from the target mRNA. Reduced activation from platelets lacking PRKAR2B supported these findings. In summary, (1) platelet miRNAs are able to repress expression of platelet proteins, (2) miRNA profiles are associated with and may predict platelet reactivity, and (3) bioinformatic approaches can successfully identify functional miRNAs in platelets.
Project description:RUNX1 transcription factor (TF) is a key regulator of megakaryocytic development and when mutated is associated with familial platelet disorder and predisposition to acute myeloid leukemia (FPD-AML). We used mice lacking Runx1 specifically in megakaryocytes (MKs) to characterize the Runx1-mediated transcriptional program during advanced stages of MK differentiation. Gene expression and chromatin-immunoprecipitation-sequencing (ChIP-seq) of Runx1 and p300 identified functional Runx1-bound MK enhancers. Runx1/p300 co-bound regions showed significant enrichment in genes important for MK and platelet homeostasis. Runx1-bound regions were highly enriched in RUNX and ETS motifs and to a lesser extent in GATA motif. The data provides the first example of genome-wide Runx1/p300 occupancy in maturating FL-MK, unravels the Runx1-regulated program controlling MK maturation in vivo and identifies its bona fide regulated genes. It advances our understanding of the molecular events that upon mutations in RUNX1 lead to the predisposition to familial platelet disorders and FPD-AML. Examination of RUNX1 and P300 binding in WT mouse megakaryoctye cells using ChIP-Seq. The supplementary 'GSE45372_PeakList.txt' file includes a list of regions identified as binding for P300 or RUNX1 or both.
Project description:Platelets contain non-coding RNAs (ncRNAs), and their measurement may complement aggregometry. In the community-based Bruneck Study (N = 338), we conducted over 2,700 aggregometry measurements and over 65,000 RT-qPCR measurements in platelet releasates, platelet-poor plasma and isolated platelets. We show agonist-specific, dose-dependent platelet ncRNA release that is inhibited by aspirin. Collagen induces the strongest release for most ncRNAs, while miR-150 is hyperresponsive to ADP and miR-21 is hyperresponsive to arachidonic acid. Inflammation and high leukocyte-derived RNA content in platelets correlate inversely with platelet aggregation and platelet ncRNA release after stimulation. This inverse correlation is not observed in aspirin users. Finally, we reveal that platelet-derived microRNAs and YRNAs are carried by proteins and readily released, while circular RNAs, long non-coding RNAs and messenger RNAs are carried by vesicles and preferentially retained. Our findings provide evidence that inflammation leads to platelet pre-activation in vivo resulting in platelet exhaustion ex vivo.