oa Editorial [Hot Topic: Platelet Proteomics in Health and Disease (Guest Editor: Wadie F. Bahou)]

This Special Edition of Current Proteomics is devoted to recent advances in blood platelets that have adapted proteomic or genomic technologies to dissect platelet function. The contents are relevant to the broad audience of biomedical researchers, clinicians, and biotechnology companies interested in novel approaches related to platelet biology. Platelets are fundamentally important in regulating normal hemostasis and pathological thrombus formation, and represent major cellular targets for drug discovery and therapeutics related to cerebro- and cardiovascular disorders. It is fully anticipated that platelet-directed therapies will likely have broader (and unexpected) therapeutic applicability, as highlighted by the recent application of platelet rich plasma as a novel therapeutic modality in sports medicine. From a historical perspective, the emergence of platelet-directed dialogues in the lay press is quite startling for cellular elements that were initially described as “particulate dust” during the early days of microscopy. This Special Edition contains seven original manuscripts from accomplished investigators that summarize basic and applied research that have re-defined the complexity of platelet biology, while developing novel model systems that will re-shape the fluctuating paradigm of platelet function. The lead two articles provide highly informative reviews that survey the range of proteomic and bioinformatic technologies that collectively serve to define the proteins and networks functionally important during quiescent and activated biologic conditions. The article by Premsler et al. presents an overview of the subcellular contents (granules, membrane composition and platelet-derived microparticles) that collectively define the platelet proteome, while the complementary article by Dittrich et al. provides insight into the dynamic networks that accompany intracellular signaling events. Presentation of a unique bioinformatic resource (PlateletWeb) that helps to dissect the functional interactome represents a highlight of this review. The article by Campbell et al. is a forward-looking review that updates the reader on the evolving field of platelet protein synthesis and translational controls, a surprisingly fresh area of investigation that delineates the capacity of blood platelets to synthesize proteins constitutively and upon activation. The related article by Landry et al. summarizes the experimental evidence and advances delineating the unique role of microRNAs as modulators of the platelet proteome. Support for this area of investigation is predicated on data highlighting the abundance and diversity of miRNAs in human platelets that among other functions may regulate expression of the platelet P2Y12 (ADP) receptor. The article by Maguire et al. was specifically included because of its application of proteomic approaches to dissect a novel pathway in platelet function (canonical Wnt pathway), with recent evidence that suppression of platelet activation and adhesion can be effected by a targeted Wnt ligand. The subsequent article by Dr. Klement provides an overview of the health-related implications of identifying plateletrestricted biomarkers as proteomic tools for disease diagnosis and monitoring. The article reviews the capacity of platelets to sequester plasma proteins, and how this provides a unique opportunity for biomarker development, emphasizing not only the interplay between platelets, angiogenesis, and cancer metastases, but also its relevance to other clinical conditions; this article is especially relevant for development of translational technologies. The Special Edition concludes with a comprehensive article on the application of new proteomic tools for identification of novel platelet targets. Building on progress in cancer and other diseases, the application and development of novel activity-based probes coupled with mass spectrometric technologies is likely to provide new insight into platelet signaling pathways and targeted drug development. In concluding, it is important to acknowledge the dedicated input of all the authors who have not only provided articles of the highest caliber, but were instrumental in providing highly thoughtful critiques that have collectively enhanced the overall quality of this Special Edition The successful completion of such a volume requires expert administrative assistance which was provided by Ms. Stacey Hondropulos.