P4pal10 is a pepducin antagonist of proteinase-activated receptor 4 (PAR4) and formyl peptide receptor 2 (FPR2), as well as an agonist of free fatty acid receptor 2 (FFAR2/GPR43).1,2 It is composed of a peptide that corresponds to the third intracellular loop of human PAR4 that is conjugated to palmitic acid .1 P4pal10 selectively inhibits the aggregation of isolated human platelets induced by the PAR4 peptide agonist AYPGKF-NH2 over the PAR1 peptide agonist SFLLRN-NH2 , the TP receptor agonist U-46619 , the platelet glycoprotein Ib (GPIb), GPIX, and GPV agonist ristocetin, ADP , or collagen at 5 µM. It inhibits increases in intracellular calcium induced by the FPR1 and FPR2 agonist WKYMVm but not by the FPR1 agonist fMLF in isolated human neutrophils and induces superoxide production in TNF-α primed isolated human neutrophils stimulated with the FFAR2 allosteric modulator Cmp58.2 P4pal10 (1, 3, or 10 µg/kg) reduces myocardial infarct size in a rat model of coronary artery ligation-induced ischemia-reperfusion injury.3 It increases the paw withdrawal threshold in rat models of osteoarthritis induced by monoiodoacetate injection into the knee joint or medial meniscal transection.4
1.Covic, L., Misra, M., Badar, J., et al.Pepducin-based intervention of thrombin-receptor signaling and systemic platelet activationNat. Med.8(10)1161-1165(2002) 2.Holdfeldt, A., Lind, S., Hesse, C., et al.The PAR4-derived pepducin P4Pal10 lacks effect on neutrophil GPCRs that couple to Gαq for signaling but distinctly modulates function of the Gαi-coupled FPR2 and FFAR2Biochem Pharmacol.114143(2020) 3.Strande, J.L., Hsu, A., Su, J., et al.Inhibiting protease-activated receptor 4 limits myocardial ischemia/reperfusion injury in rat hearts by unmasking adenosine signalingJ. Pharmacol. Exp. Ther.324(3)1045-1054(2008) 4.O'Brien, M.S., and McDougall, J.J.Targeting proteinase activated receptor-4 reduces mechanonociception during the acute inflammatory phase but not the chronic neuropathic phase of osteoarthritis in ratsFront. Pharmacol.12756632(2021)