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Mutations in transcription factor RUNX1 are associated with familial platelet disorder, thrombocytopenia, and predisposition to leukemia. We have described a patient with thrombocytopenia and impaired agonist-induced platelet aggregation, secretion, and glycoprotein (GP) IIb-IIIa activation, associated with a RUNX1 mutation. Platelet myosin light chain(More)
In the majority of patients with an inherited abnormality in platelet function and a bleeding diathesis, the underlying platelet molecular mechanisms are unknown. The usually considered entities, such as thrombasthenia, the Bernard-Soulier syndrome, and storage pool deficiency, occur in a small proportion of patients. A substantial number of patients(More)
Tissue factor (TF) is the physiological initiating mechanism for blood coagulation. Platelets play an important role in monocyte TF expression, thrombosis and inflammation. Aspirin, clopidogrel and cilostazol, which inhibit platelet responses by different mechanisms, are widely used in patients with arterial diseases. We tested the hypothesis that(More)
Haploinsufficiency of RUNX1 (also known as CBFA2/AML1) is associated with familial thrombocytopenia, platelet dysfunction, and predisposition to acute leukemia. We have reported on a patient with thrombocytopenia and impaired agonist-induced aggregation, secretion, and protein phosphorylation associated with a RUNX1 mutation. Expression profiling of(More)
BACKGROUND Galphaq (Gene GNAQ) plays a major role in platelet signal transduction but little is known regarding its transcriptional regulation. OBJECTIVES We studied Galphaq promoter activity using luciferase reporter gene assays in human erythroleukemia (HEL) cells treated with phorbol 12-myristate 13-acetate (PMA) for 24 h to induce megakaryocytic(More)
BACKGROUND Platelet factor 4 (PF4) is an abundant protein stored in platelet α-granules. Several patients have been described with platelet PF4 deficiency, including the gray platelet syndrome, characterized by a deficiency of α-granule proteins. Defective granule formation and protein targeting are considered to be the predominant mechanisms. We have(More)
OBJECTIVE Mutations in the hematopoietic transcription factor RUNX1 cause thrombocytopenia and impaired platelet function. In a patient with a heterozygous mutation in RUNX1, we have described decreased platelet pleckstrin phosphorylation and protein kinase C- (PKC-, gene PRKCQ) associated with thrombocytopenia, impaired platelet aggregation, and dense(More)
Essentials Platelet dense granule (DG) deficiency is a major abnormality in RUNX1 haplodeficiency patients. The molecular mechanisms leading to the platelet DG deficiency are unknown. Platelet expression of PLDN (BLOC1S6, pallidin), involved in DG biogenesis, is regulated by RUNX1. Downregulation of PLDN is a mechanism for DG deficiency in RUNX1(More)
Aspirin prevents cardiovascular disease and colon cancer; however aspirin's inhibition of platelet COX-1 only partially explains its diverse effects. We previously identified an aspirin response signature (ARS) in blood consisting of 62 co-expressed transcripts that correlated with aspirin's effects on platelets and myocardial infarction (MI). Here we(More)
Galphaq plays a major role in platelet signal transduction, but little is known regarding its transcriptional regulation. We have reported that Galphaq is upregulated during phorbol 12-myristate 13-acetate (PMA)-induced megakaryocytic transformation of human erythroleukemia (HEL) cells and regulated by EGR-1, an early growth transcription factor. These(More)