Maria Lopes Pires

My research interests focus on the intracellular mechanisms involved in platelet signalling and reactive oxygen species (ROS).

Much of my experience to date has being in the role of platelets in sepsis.  I have gained significant experience with in vivo (animal models) and isolation and functional analysis of human platelets. As part of my research, I showed that the treatment of rats with lipopolysaccharide (LPS) affects platelet aggregation through intraplatelet ROS generation. The increased intraplatelet ROS production does not contribute to the inhibitory effect of LPS in vivo on platelet aggregation, however, the maintenance of redox balance in LPS-treated rats is fundamental to restore the normal platelet response in these animals. In addition, we showed that the inhibition of rat platelet aggregation by LPS is mediated by cGMP/PKG-dependent mechanisms. PKC and AKT play a role in the inhibitory effects of LPS on platelet aggregation by acting as upstream modulators of the cGMP/ PKG pathway. In my recent work at the University of Reading with Prof Jon Gibbins, we sought to explore the signalling pathways through which LPS in vitro modulates platelets regulation.

My current research is focused on the relationship between zinc ions and platelets with Dr Nicholas Pugh. Zinc ions are also released from platelets and damaged cells and have been shown to act as a platelet agonist. However, the mechanism of zinc-induced platelet activation is not well understood. The group has showed that zinc enters the platelet cytosol and regulates protein phosphorylation-dependent platelet signalling events, leading to granule release and full PKC-mediated aIIbb3-dependent aggregation.