GATA1 pathogenic variants disrupt MYH10 silencing during megakaryopoiesis.

Background: GATA1 is an essential transcription factor for both polyploidization and megakaryocyte (MK) differentiation. The polyploidization defect observed in GATA1 variant carriers is not well understood.

Objective: To extensively phenotype two pedigrees displaying different variants in the GATA1 gene and determine if GATA1 controls MYH10 expression levels, a key modulator of MK polyploidization.

CD169 and CD64 could help differentiate bacterial from CoVID-19 or other viral infections in the Emergency Department.

The identification of a bacterial, viral, or even noninfectious cause is essential in the management of febrile syndrome in the emergency department (ED), especially in epidemic contexts such as flu or CoVID-19. The aim was to assess discriminative performances of two biomarkers, CD64 on neutrophils (nCD64) and CD169 on monocytes (mCD169), using a new flow cytometry procedure, in patients presenting with fever to the ED during epidemics. Eighty five adult patients presenting with potential infection were included during the 2019 flu season in the ED of La Timone Hospital.

Antiplatelet Agents Have a Distinct Efficacy on Platelet Aggregation Induced by Infectious Bacteria.

Platelets are the cornerstone of hemostasis. However, their exaggerated aggregation induces deleterious consequences. In several diseases, such as infectious endocarditis and sepsis, the interaction between platelets and bacteria leads to platelet aggregation.

Flow cytometry evaluation of infection-related biomarkers in febrile subjects in the emergency department.

In an Emergency Department (ED), the etiological identification of infected subjects is essential. 13 infection-related biomarkers were assessed using a new flow cytometry procedure. If subjects presented with febrile symptoms at the ED, 13 biomarkers' levels, including CD64 on neutrophils (nCD64) and CD169 on monocytes (mCD169), were tested and compared with clinical records.

Platelet CD40 ligand and bleeding during P2Y12 inhibitor treatment in acute coronary syndrome.

Antiplatelet therapy through inhibition of the adenosine diphosphate (ADP)/P2Y12 pathway is commonly used in the treatment of acute coronary syndrome (ACS). Although efficient in preventing platelet activation and thrombus formation, it increases the risk of bleeding complications. In patients with ACS receiving platelet aggregation inhibitors, that is, P2Y12 blockers (n = 923), we investigated the relationship between plasma and platelet-associated CD40L levels and bleeding events (n = 71).

A Novel Rapid Method of Red Blood Cell and Platelet Permeabilization and Staining for Flow Cytometry Analysis.

Background: Flow cytometry essentially focuses on surface-expressed proteins, with few protocols being devoted to intracellular components. We evaluated a two-step procedure using new formaldehyde-free permeabilization and staining reagents that allow the staining of platelets and red blood cells (RBCs) from whole blood.

Methods: Citrated blood was treated with the new staining protocol (NSP) or control reagent (phosphate-buffered solution bovine serum albumin) and stained with antibodies against surface or intracellular markers.

Early (Day 15 Post Diagnosis) Peripheral Blood Assessment of Measurable Residual Disease in Flow Cytometry is a Strong Predictor of Outcome in Childhood B-Lineage Lymphoblastic Leukemia.

Background: In children with acute lymphoblastic leukemia (ALL) low levels of minimal residual disease (MRD) after induction, essentially assessed in the bone marrow, have been shown to be of good prognosis. However, only few studies have tested the peripheral blood for MRD.

Methods: Here, we report the impact on survival of peripheral blood (PB) MRD assessment by multiparameter flow cytometry (MFC) at early time points of treatment in 125 B-ALL children, compared to Day 35 molecular bone marrow (BM) MRD.

Detection of Minimal Residual Disease in B Cell Acute Lymphoblastic Leukemia Using an Eight-Color Tube with Dried Antibody Reagents.

Background: Flow cytometry is a powerful tool for the detection of minimal residual disease (MRD) of B cell precursor acute lymphoblastic leukemia (BCP-ALL) patients. However, the staining process and the choice of antibodies rely on laboratory expertise and may be source of variability or technical errors. Recently, Beckman Coulter commercialized a ready to use tube with dried format reagents for BCP-ALL MRD detection.

Southeast asian ovalocytosis: the need for a carefull observation of red cell indices and blood smear.

Southeast asian ovalocytosis (SAO) is characterized by macro-ovalocytes and ovalo-stomatocytes on blood smear. SAO is common in Malaisia and Papua-New-Guinea where upwards to 40 per cent of the population is affected in some coastal region. Inherited in an autosomal dominant way, illness results from deletion of codons 400-408 in SLC4A1 gene which encodes for band 3 erythrocyte membrane protein.

Macrothrombocytopenia and dense granule deficiency associated with FLI1 variants: ultrastructural and pathogenic features.

Congenital macrothrombocytopenia is a family of rare diseases, of which a significant fraction remains to be genetically characterized. To analyze cases of unexplained thrombocytopenia, 27 individuals from a patient cohort of the Bleeding and Thrombosis Exploration Center of the University Hospital of Marseille were recruited for a high-throughput gene sequencing study. This strategy led to the identification of two novel variants (c.

Germline variants in ETV6 underlie reduced platelet formation, platelet dysfunction and increased levels of circulating CD34+ progenitors.

Variants in ETV6, which encodes a transcription repressor of the E26 transformation-specific family, have recently been reported to be responsible for inherited thrombocytopenia and hematologic malignancy. We sequenced the DNA from cases with unexplained dominant thrombocytopenia and identified six likely pathogenic variants in ETV6, of which five are novel. We observed low repressive activity of all tested ETV6 variants, and variants located in the E26 transformation-specific binding domain (encoding p.

All-trans retinoic acid induces oxidative phosphorylation and mitochondria biogenesis in adipocytes.

A positive effect of all-trans retinoic acid (ATRA) on white adipose tissue (WAT) oxidative and thermogenic capacity has been described and linked to an in vivo fat-lowering effect of ATRA in mice. However, little is known about the effects of ATRA on mitochondria in white fat. Our objective has been to characterize the effect of ATRA on mitochondria biogenesis and oxidative phosphorylation (OXPHOS) capacity in mature white adipocytes.

The plasminogen activation system modulates differently adipogenesis and myogenesis of embryonic stem cells.

Regulation of the extracellular matrix (ECM) plays an important functional role either in physiological or pathological conditions. The plasminogen activation (PA) system, comprising the uPA and tPA proteases and their inhibitor PAI-1, is one of the main suppliers of extracellular proteolytic activity contributing to tissue remodeling. Although its function in development is well documented, its precise role in mouse embryonic stem cell (ESC) differentiation in vitro is unknown.

Plasminogen activator inhibitor 1 is an intracellular inhibitor of furin proprotein convertase.

Proprotein convertases (PCs) are a family of serine proteases that are involved in the post-translational processing and activation of a wide range of regulatory proteins. The upstream role of PCs in the control of many physiological and pathological processes generates a growing interest in understanding their regulation. Here, we demonstrate that the serine protease inhibitor plasminogen activator inhibitor 1 (PAI-1) forms an SDS-stable complex with the PC furin, which leads to the inhibition of the intra-Golgi activity of furin.

p38 mitogen activated protein kinase controls two successive-steps during the early mesodermal commitment of embryonic stem cells.

Embryonic stem (ES) cells differentiate in vitro into all cell lineages. We previously found that the p38 mitogen activated kinase (p38MAPK) pathway controls the commitment of ES cells toward either cardiomyogenesis (p38 on) or neurogenesis (p38 off ). In this study, we show that p38α knock-out ES cells do not differentiate into cardiac, endothelial, smooth muscle, and skeletal muscle lineages.

Down-regulation of tissue inhibitor of metalloproteinase-3 (TIMP-3) expression is necessary for adipocyte differentiation.

Matrix metalloproteinase activity is essential for proper extracellular matrix remodeling that takes place during adipose tissue formation. Four tissue inhibitors of matrix metalloproteinases (TIMPs) regulate their activity. However, the role of TIMPs in adipocyte differentiation is poorly understood.

Proteasome inhibition activates the transport and the ectodomain shedding of TNF-alpha receptors in human endothelial cells.

Binding of tumor necrosis factor-alpha (TNF-alpha) to its transmembrane receptors (TNFRs) mediates proinflammatory, apoptotic and survival responses in several cell types including vascular endothelial cells. Because ectodomain shedding of cell surface molecules can be modified by proteasome activity, we studied in human endothelial cells whether the TNF-alpha-TNFRs axis can be regulated by the cleavage of their transmembrane forms in a proteasome-dependent manner. We show that proteasome inhibition increases the release of TNF-alpha and TNFRs from human endothelial cells and decreases their cellular and cell surface expression.

Proinflammatory properties of murine aortic endothelial cells exclusively expressing a non cleavable form of TNFalpha. Effect on tumor necrosis factor alpha receptor type 2.

Soluble (sTNF) and transmembrane (tmTNF) forms of TNFalpha (TNF) have distinct proinflammatory effects. We investigated whether tmTNF altered the synthesis of some proinflammatory proteins involved in atherothrombosis, in murine aortas and aortic endothelial cells (MAEC). Samples were obtained from wild-type (WT) mice and TNF-deficient mice that express a mutated non cleavable tmTNF transgene (tmTNFnc).

Upregulation of TNF-alpha-induced ICAM-1 surface expression by adenylate cyclase-dependent pathway in human endothelial cells.

The level of adhesion molecules expressed at the endothelial cell surface is critical in the control of inflammation. Adenylate cyclase (AC) activity allowing cyclic adenosine monophosphate (cAMP) production can modulate the inflammatory process. We investigated the AC-dependent modulation of ICAM-1 surface expression in human umbilical venous endothelial cells (HUVEC).

Modulation of PAI-1 and proMMP-9 syntheses by soluble TNFalpha and its receptors during differentiation of the human monocytic HL-60 cell line.

During phorbol ester-induced differentiation of HL-60 monocytic cells, tumor necrosis factoralpha (TNFalpha) synthesis and secretion are increased, which contributes to the autocrine regulation of TNFalpha-responsive genes. We investigated how, during phorbol ester-induced differentiation of HL-60 cells, the secreted TNFalpha modulated plasminogen activator inhibitor type I (PAI-1) and gelatinase B (MMP-9) syntheses, two proteins involved in pericellular proteolysis. The differentiation-induced release of TNFalpha, was abolished by the hydroxamate-based matrix metalloproteinase (MMP) inhibitor, RU36156.

Genomic organization and alternative transcripts of the human Connexin40 gene.

The human Cx40 gene (NT_004434.5) was sorted out from the GenBank database and as a result of a BLAST homology search, two ESTs (BE784549 from a human lung database, and BE732411 from a human placenta database) overlapping with the coding exon 2 sequence and upstream regions of the gene were identified. These ESTs correspond to two transcripts 1A and 1B, which diverge from each other in their 5' regions.

Effect of atorvastatin on adhesive phenotype of human endothelial cells activated by tumor necrosis factor alpha.

We studied the effect of atorvastatin on the adhesive phenotype of human endothelial cells (HUVEC) stimulated by tumor necrosis factor (TNF)-alpha. Surface expression of adhesion molecules on HUVEC was examined by flow cytometry and confocal microscopy, and adhesion of monocytes (human THP-1 cell line) was measured in vitro under flow conditions. In TNF-alpha-activated HUVEC, atorvastatin significantly enhanced surface expression of vascular cell adhesion molecule (VCAM)-1, intercellular adhesion molecule (ICAM)-1, E-selectin, and fractalkine, when compared with TNF-alpha stimulation alone.