Apelin-12 is a 12-amino acid peptide fragment corresponding to residues 66-77 of apelin and an endogenous agonist of the apelin receptor (APJ), with roles in viral immunity, digestion, cell cycle regulation, and vasodilation.1 It induces calcium mobilization in APJ-Gαq16 cells expressing human APJ (EC50 = 0.18 nM). Apelin-12 inhibits HIV-1 and HIV-2 infection in NP-2/CD4/APJ cells (mean IC50 = 63 µg/ml).2 It inhibits or stimulates the expression of genes associated with apoptosis, mitosis, and DNA repair in IEC-6 and Caco-2 cells, respectively, when used at a concentration of 0.01 µM.3 Apelin-12 (100-1,000 nM) induces the production of nitric oxide (NO) via PI3K and Akt signaling pathways in human umbilical vein endothelial cells (HUVECs).4 In vivo, apelin-12 (20-100 µg/kg) increases gastric acid secretion, as well as stomach histamine synthesis and secretion, in rats.5 It also reduces mean arterial pressure (MAP) in rats when administered at a dose of 15 µg/kg.6
1.Giddings, A., Runyon, S., Thomas, J., et al.Development of a functional HTS assay for the APJ receptorInt. J. High Throughput Screen.139-47(2010) 2.Zou, M.X., Liu, H.Y., Haraguchi, Y., et al.Apelin peptides block the entry of human immunodeficiency virus (HIV)FEBS Lett.473(1)15-18(2000) 3.Antushevich, H., Krawczynska, A., Kapica, M., et al.Effect of apelin on mitosis, apoptosis and DNA repair enzyme OGG 1/2 expression in intestinal cell lines IEC-6 and Caco-2Folia Histochem. Cytobiol.52(1)51-59(2014) 4.Busch, R., Strohbach, A., Pennewitz, M., et al.Regulation of the endothelial apeliPJ system by hemodynamic fluid flowCell. Signal.27(7)1286-1296(2015) 5.Ohno, S., Yakabi, K., Ro, S., et al.Apelin-12 stimulates acid secretion through an increase of histamine release in rat stomachsRegul. Pept.174(1-3)71-79(2012) 6.Lee, D.K., Saldivia, V.R., Nguyen, T., et al.Modification of the terminal residue of apelin-13 antagonizes its hypotensive actionEndocrinology146(1)231-236(2005)