Platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) is a biologically active phospholipid mediator that was first described by its ability to cause platelet aggregation and dilation of blood vessels. In addition, PAF acts as a mediator of cell-to-cell communication, inflammation, allergic responses and shock¹.

PAF acts on PAF receptor (PAFR) a G protein-coupled receptor (GPCR). It consists of 7 transmembrane-spanning domains (TMDs), and two potential N-linked glycosylation sites. PAFR was found to expressed in the lung, neutrophils, monocytes, macrophages, placenta, small intestine, heart, liver, kidney, brain, and spleen. As a results of PAF interaction, PAFR is coupled to Gq protein and consequently activates various downstream signaling pathways².

Experiments in both PAF receptor knockout animals and transgenic animals overexpressing PAF receptors support the pathophysiological role attributed to PAF receptor signaling. For example, Mice model of obstructive nephropathy show that PAFR signaling contributes to a pro-inflammatory environment leading to renal dysfunction and progressive organ failure³. In addition, inhibition of PAFR signaling results in an effective inhibition of experimental tumor growth and metastasis⁴.