Inherited dysfunctional platelet P2Y receptor mutations associated with bleeding disorders.

The platelet adenosine 5'-diphosphate (ADP) receptor P2Y (P2YR) plays a critical role in platelet aggregation. The present report illustrates an update of dysfunctional platelet P2YR mutations diagnosed with congenital lifelong bleeding problems. Described patients with heterozygous or homozygous substitution in the P2YR gene and qualitative abnormalities of the platelet P2YR are summarized.

Hemostatic properties and protein expression profile of therapeutic apheresis plasma treated with amotosalen and ultraviolet A for pathogen inactivation.

Background: The INTERCEPT Blood System (IBS) using amotosalen-HCl and ultraviolet (UV)A inactivates a large spectrum of microbial pathogens and white blood cells in therapeutic plasma. Our aim was to evaluate to what extent IBS modifies the capacity of plasma to generate thrombin and induces qualitative or quantitative modifications of plasma proteins.

Study Design And Methods: Plasma units from four donors were collected by apheresis.

In Vitro Binding of [³H]PSB-0413 to P2Y₁₂ Receptors.

The P2Y₁₂/ADP receptor plays a central role in platelet activation. Characterization of this receptor is mandatory for studying disorders associated with a P2Y₁₂ receptor defect and for evaluating P2Y₁₂ receptor agonists and antagonists. In the absence of suitable anti-P2Y₁₂ antibodies, radioligand binding assays are the only way to conduct such studies.

Identification of a new dysfunctional platelet P2Y12 receptor variant associated with bleeding diathesis.

Defects of the platelet P2Y12 receptor (P2Y12R) for adenosine diphosphate (ADP) are associated with increased bleeding risk. The study of molecular abnormalities associated with inherited qualitative defects of the P2Y12R protein is useful to unravel structure-function relationships of the receptor. We describe the case of 2 brothers, sons of first cousins, with lifelong history of abnormal bleeding, associated with dysfunctional P2Y12R and a previously undescribed missense mutation in the encoding gene.

Preserved functional and biochemical characteristics of platelet components prepared with amotosalen and ultraviolet A for pathogen inactivation.

Background: Platelet concentrate (PC) functionality decreases during storage. This is referred to as the storage lesion. Pathogen inactivation may accelerate or induce lesions, potentially accounting for reduced viability.

The platelet P2Y(12) receptor under normal and pathological conditions. Assessment with the radiolabeled selective antagonist [(3)H]PSB-0413.

Various radioligands have been used to characterize and quantify the platelet P2Y(12) receptor, which share several weaknesses: (a) they are metabolically unstable and substrates for ectoenzymes, (b) they are agonists, and (c) they do not discriminate between P2Y(1) and P2Y(12). We used the [(3)H]PSB-0413 selective P2Y(12) receptor antagonist radioligand to reevaluate the number of P2Y(12) receptors in intact platelets and in membrane preparations. Studies in humans showed that: (1) [(3)H]PSB-0413 bound to 425 ± 50 sites/platelet (K (D) = 3.

Quantification of recombinant and platelet P2Y(1) receptors utilizing a [(125)I]-labeled high-affinity antagonist 2-iodo-N(6)-methyl-(N)-methanocarba-2'-deoxyadenosine-3',5'-bisphosphate ([(125)I]MRS2500).

The ADP-activated P2Y(1) receptor is broadly expressed and plays a crucial role in ADP-promoted platelet aggregation. We previously synthesized 2-iodo-N(6)-methyl-(N)-methanocarba-2'-deoxyadenosine-3',5'-bisphosphate (MRS2500), as a selective, high-affinity, competitive antagonist of this receptor. Here we report utilization of a trimethylstannyl precursor molecule for the multi-step radiochemical synthesis of a [(125)I]-labeled form of MRS2500.

Use of tandem Biacore-mass spectrometry to identify platelet membrane targets of novel monoclonal antibodies.

The monoclonal antibodies (mAbs) ALMA.17 and ALMA.7 recognize human platelet membrane proteins.

The plaque lipid lysophosphatidic acid stimulates platelet activation and platelet-monocyte aggregate formation in whole blood: involvement of P2Y1 and P2Y12 receptors.

Despite the fact that lysophosphatidic acid (LPA) has been identified as a main platelet-activating lipid of mildly oxidized low-density lipoprotein (LDL) and human atherosclerotic lesions, it remains unknown whether it is capable of activating platelets in blood. We found that LPA at concentrations slightly above plasma levels induces platelet shape change, aggregation, and platelet-monocyte aggregate formation in blood. 1-alkyl-LPA (16:0 fatty acid) was almost 20-fold more potent than 1-acyl-LPA (16:0).