Common mechanism in endothelin-3 and PAF receptor function for anti-inflammatory responses

Platelet-activating factor (PAF) is a potent lipid mediator that is implicated in numerous inflammatory diseases. Under inflammatory conditions, PAF is biosynthesized through the remodelling pathway and elicits many inflammatory responses through binding to its specific PAF receptor. Endogenous bioactive endothelins (ETs: ET-1, -2, and -3) are also considered potent inflammatory mediators that play a critical role in many inflammatory diseases. In this perspective, we provide a brief overview of possible common mechanisms in ETs and PAF receptor function for inflammatory responses. Accumulating evidence strongly suggests that ET-3, but not ET-1 and ET-2, can attenuate PAF-induced inflammation through direct binding of the Tyr-Lys-Asp (YKD) region in the peptide to PAF and its metabolite/precursor lyso-PAF, followed by inhibition of binding between PAF and its receptor. Additionally, YKD sequence-containing peptides may be useful as a novel type of anti-inflammatory drugs targeting this mechanism. These findings should lead to new treatment strategies for numerous inflammatory diseases by targeting the common mechanism in ET and PAF receptor function.