Electrophilic eicosanoids: Signaling and targets

Electrophilic eicosanoids are reactive mediators that arise by non-enzymatic transformations of arachidonic acid or of its products and display varied biological actions. Various electrophilic eicosanoids have shown anti-proliferative and anti-inflammatory effects, which have elicited a great interest in their study as potential therapeutic agents. A key feature of these compounds is their ability to covalently modify proteins, thus altering their structure and function. The modification of several components of the NF-κB pathway contributes to the anti-inflammatory effects of electrophilic eicosanoids, whereas addition to redox-sensitive proteins plays a key role in the antioxidant response. However, electrophilic eicosanoids may also have a dark side, and accumulating evidence points towards their involvement in neurotoxicity and/or neurodegeneration. The ability of some electrophilic eicosanoids to induce protein oligomerization or aggregation through various mechanisms may contribute to these effects. Biochemical and proteomic studies have led to the identification of numerous protein targets for modification by electrophilic eicosanoids, the number of which continues to expand, revealing novel potential functions for these compounds and providing a basis for their pleiotropic effects. The ample number of targets identified, together with the non-enzymatic nature of the modification argue against the potential specificity or regulation of electrophilic eicosanoid action. However, protein modification displays selectivity depending on structural features of the proteins and of the electrophilic compounds as well as on context factors such as cell type and GSH availability. Understanding the factors which control the extent and selectivity of protein modification by electrophilic eicosanoids is therefore essential to elucidate their pathophysiological roles and therapeutic potential in specific settings.