Project description:The purpose of this study was to perform an unbiased RNA expression profile in platelets from HIV subjects under ART and healthy controls to identify a gene signature for the HIV hyperactive phenotype. Methods: Rna-Sequencing was performed in leukocyte-depleted platelet RNA from 6 HIV subjects and 3 healthy controls. qRT–PCR validation was performed to validate our candidate transcripts. Results: Across the 9 platelet samples, there was an average of 28.3 million mapped reads per sample with an average unique mapping rate of 91.6 %. Using a cut-off of normalized counts ≥1 across the 9 samples, we found 11988 expressed transcripts. Conclusions: Our study represents a detailed analysis of platelet transcriptome generated by RNA-seq technology in HIV patients under ART. Further experiments identified the mechanism of our transcript target in mediating platelet activity and platelet cell effector function.
Project description:Results: MiRNA expression profiling of 1281 human miRNAs revealed relevant expression of 221 miRNAs consistently expressed in all samples at all time points. Correlation of platelet miRNA ranks was highly significant with data from other studies. Global distribution of miRNA expression was relatively similar in all subjects. No miRNA exhibited a significant effect of time at level 0.05. This finding was supported by exploratory analysis of predicted time effects from the mixed effects models. Furthermore, no significant effect of ASA could be found. Concerning the functional implication of the 20 most abundantly expressed miRNAs, we found 6 functional themes: nuclear import, cell cycle, transmembrane receptor protein serine/threonine kinase signaling pathway, regulation of kinase activity, pathways in cancer, and leukocyte differentiation. Conclusion: Our study shows that the platelet miRNA profile is remarkably stable in healthy subjects and is not affected by single-dose ASA treatment. For this reason, single-point analysis of platelet miRNA profile is reasonable when inter-individual differences are studied. The functional annotation network points toward additional extra-platelet effects of platelet miRNAs.
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:A common feature in patients with abdominal aortic aneurysms (AAA) is the formation of a nonocclusive intraluminal thrombus (ILT) in regions of aortic dilation. Platelets are known to maintain hemostasis and propagate thrombosis through several redundant activation mechanisms, yet the role of platelet activation in the pathogenesis of AAA associated ILT is still poorly understood. Thus, we sought to investigate how platelet activation impacts the pathogenesis of AAA. Using RNA-sequencing, we identify that the platelet-associated transcripts are significantly enriched in the ILT compared to the adjacent aneurysm wall and healthy control aortas. We found that the platelet specific receptor glycoprotein VI (GPVI) is among the top enriched genes in AAA ILT and is increased on the platelet surface of AAA patients. Examination of a specific indicator of platelet activity, soluble GPVI (sGPVI), in two independent AAA patient cohorts is highly predictive of a AAA diagnosis and associates more strongly with aneurysm growth rate when compared to D-dimer in humans. Finally, intervention with the anti-GPVI antibody (JAQ1) in mice with established aneurysms blunted the progression of AAA in two independent mouse models. In conclusion, we show that levels of sGPVI in humans can predict a diagnosis of AAA and AAA growth rate, which may be critical in the identification of high-risk patients. We also identify GPVI as a novel platelet-specific AAA therapeutic target, with minimal risk of adverse bleeding complications, where none currently exist.
Project description:Recent technological advances have made transcriptome sequencing (RNA-seq) possible in cells with low RNA copy number including platelets. Resulting studies have used RNA-seq in platelets isolated from healthy individuals to characterize the platelet transcriptome. However, platelets, possibly through gene expression changes, contribute to the etiology of and response to cardiovascular disease and events. To address this, we performed the largest human platelet RNA-seq analysis to date in 34 platelet samples: 16 ST-segment elevation myocardial infarction (STEMI), 16 non-STEMI (NSTEMI), and 2 controls. RNA-seq of platelet samples from 34 individuals: 16 with ST-elevation myocardial infarction (STEMI), 16 with non-STEMI, and 2 non-myocardial infarction controls
Project description:RNA-sequencing analysis of human platelet rRNA-depleted total RNA from two normal males and one female. The goal of this experiment was to identify genes expressed in unstimulated circulating platelets. Data from platelet polyA-mRNA has also been deposited at ArrayExpress, under accession number E-MTAB-715, https://www.ebi.ac.uk/arrayexpress/experiments/E-MTAB-715/ .
Project description:Results: MiRNA expression profiling of 1281 human miRNAs revealed relevant expression of 221 miRNAs consistently expressed in all samples at all time points. Correlation of platelet miRNA ranks was highly significant with data from other studies. Global distribution of miRNA expression was relatively similar in all subjects. No miRNA exhibited a significant effect of time at level 0.05. This finding was supported by exploratory analysis of predicted time effects from the mixed effects models. Furthermore, no significant effect of ASA could be found. Concerning the functional implication of the 20 most abundantly expressed miRNAs, we found 6 functional themes: nuclear import, cell cycle, transmembrane receptor protein serine/threonine kinase signaling pathway, regulation of kinase activity, pathways in cancer, and leukocyte differentiation. Conclusion: Our study shows that the platelet miRNA profile is remarkably stable in healthy subjects and is not affected by single-dose ASA treatment. For this reason, single-point analysis of platelet miRNA profile is reasonable when inter-individual differences are studied. The functional annotation network points toward additional extra-platelet effects of platelet miRNAs. We assessed the platelet miRNA profile blood in 5 volunteers at five time points over a time course of 10 days; 24 h prior to the last blood sampling, all subjects took 500 mg acetylsalicylic acid (ASA) once. Platelet miRNA was isolated from platelet-rich plasma which was leucocyte-depleted by negative bead separation. Then miRNA array analysis was performed on the isolated platelet miRNA. Temporal patterns and the effect of ASA were explored by a linear mixed effects model for each miRNA. For the 20 most abundantly expressed platelet miRNAs, a target gene search was performed by using miRWalk for validated and predicted targets. To visualize which molecular functions arerelated to those miRNAs, an annotation network was created by ClueGO, a Cytoscape plug-in.
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:In sickle cell disease, ischemia-reperfusion injury and intravascular hemolysis produce endothelial dysfunction and vasculopathy characterized by reduced nitric oxide (NO) and arginine bioavailability. Recent functional studies of platelets in patients with sickle cell disease reveal a basally activated state, suggesting that pathological platelet activation may contribute to sickle cell disease vasculopathy. Studies were therefore undertaken to examine transcriptional signaling pathways in platelets that may be dysregulated in sickle cell disease. We demonstrate and validate here the feasibility of comparative platelet transcriptome studies on clinical samples from single donors, by the application of RNA amplification followed by microarray-based analysis of 54,000 probe sets. Data mining an existing microarray database, we identified 220 highly abundant genes in platelets and a subset of 72 relatively platelet-specific genes, defined by more than 10-fold increased expression compared to the median of other cell types in the database with amplified transcripts. The highly abundant platelet transcripts found in the current study included 82% or 70% of platelet abundant genes identified in two previous gene expression studies on non-amplified mRNA from pooled or apheresis samples, respectively. On comparing the platelet gene expression profiles in 18 patients with sickle cell disease in steady state to 12 African American controls, at a 3-fold cut-off and 5% false discovery rate, we identified ~100 differentially expressed genes, including multiple genes involved in arginine metabolism and redox homeostasis. Further characterization of these pathways using real time PCR and biochemical assays revealed increased arginase II expression and activity and decreased platelet polyamine levels. These studies suggest a potential pathogenic role for platelet arginase and altered arginine and polyamine metabolism in sickle cell disease and provide a novel framework for the study of disease-specific platelet biology. Experiment Overall Design: There are 18 sickle cell samples and 12 control samples from healthy African American volunteers.