The value of proteomics for the diagnosis of a platelet-related bleeding disorder

Abstract

Familial bleeding problems are frequently difficult to diagnose because currently used clinical tests cannot identify intracellular molecular defects of platelets. Using platelet proteomics, a comprehensive analytical tool, we diagnosed a family with severe bleeding problems of unknown origin with Quebec Platelet Disorder. Prior to proteomic analysis, we determined platelet counts, presence of glycoprotein (GP) Ib and GPIIb/IIIa, platelet aggregation, dense granule content and release, plasma levels of fibrinogen, Factor XIII and fibrin degradation products in four family members. Abnormalities were detected in platelet aggregation studies, which revealed variably reduced responses to ADP, collagen and epinephrine with concomitantly decreased ATP/serotonin secretion. In addition, D-dimer levels were significantly elevated 72 hours after in vitro thrombin stimulation of platelet-rich plasma. Together with the autosomal dominant inheritance and the delayed onset of bleeding in two of the four patients these results did not support any known platelet disorder. Therefore, the proteome of platelet lysates separated by one-dimensional SDS-PAGE was analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Platelet proteomics showed reduced amounts of alpha-granule proteins multimerin, fibrinogen and thrombospondin-1 in patient compared to control samples suggestive of Quebec Platelet Disorder. The diagnosis of Quebec Platelet Disorder was confirmed by urokinase-specific Western blots. Urokinase causes the degradation of alpha-granule proteins in this disorder. Diagnosis of rare bleeding disorders has important implications for prophylactic and acute treatment of bleeding patients. This is the first report using proteomics to identify a familial platelet defect.

The platelet proteome

“…Recently, proteomic techniques identified a diagnosis of Quebec Platelet Disorder in a family with severe bleeding problems of unknown origin[26**]. While clinical features were not clearly suggestive of the disorder, LC-MS/MS revealed reduced amounts of alpha granule proteins which led to the correct diagnosis.…”

Platelet proteomics in diagnostic differentiation of primary immune thrombocytopenia using SELDI-TOF-MS

“…The similarities and differences of protein expression and modification under various physiological and pathological conditions can provide novel insights into protein identification and classification, as well as protein interaction and function analysis [17]. The application of platelet proteomics has been explored in areas such as platelet-related diseases [25], type 2 diabetes [26,27], and acute coronary syndrome [28], providing pathogenic information of the diseases and highlighting biomarkers for new drug targets.…”

Platelet proteomics

“…Patients affected by a Bernard-Soulier syndrome present gingival and mucocutaneous bleeding, hemorrhage after trauma and epistaxis (Salles et al, 2008). Maurer-Spurej et al (2008) have published the first report of the identification of a familial platelet defect by proteomics, in 2008. They studied the platelet proteome of 4 family members presenting severe bleeding problems.…”