Platelets (green) produce IL-1β (red) during a clotting reaction.
Platelets get no respect. Traditionally, these anucleate cells have been acknowledged as critical mediators of blood clotting, but they were considered metabolically challenged drones, incapable of signal-dependent gene expression. Now, Lindemann et al. (page 485) demonstrate that platelets are not only able to translate preformed mRNAs in response to environmental signals, they may also provide an important link between the coagulation and inflammatory cascades via regulated production of an inflammatory cytokine.
Using an arrayed cDNA library, the authors identified a variety of mRNAs present in resting platelets, including one encoding the interleukin-1β (IL-1β) precursor. Activation of the platelets as in clot formation triggers IL-1β production; the IL-1β then induces adhesiveness of endothelial cells for neutrophils, an inflammatory reaction. The platelet- produced IL-1β accumulates over a period of several hours, indicating that platelets can exert...
