Chemerin-derived peptide C-20 suppressed gonadal steroidogenesis.

Problem: Chemerin is a novel chemo-attractant and adipokine involved in leukocyte recruitment, inflammation, adipogenesis, lipid/carbohydrate metabolism, and reproduction. Based on the bioinformatic search for putative small peptides in the conserved region of pre-pro-chemerin, an evolutionary conserved region flanked by potential convertase cleavage sites was identified and we named it as C-20. The binding capacity of C-20 to chemerin receptors and its potential bioactivities were investigated in this study.

Method Of Study: Radioligand binding assay, receptor internalization assay, and early response gene C-FOS simulation, cAMP assay were carried out in chemokine-like receptor 1 (CMKLR1)/HEK293 transfectants and G protein-coupled receptor 1 (GPR1)/HEK293 transfectants. In vitro transwell chemotaxis assay in CMKLR1/L1.2 transfectants, primary Leydig cell culture, and antral follicle culture was explored to investigate the bioactivity of C-20.

Results: C-20 bound to chemerin receptors CMKLR1 and GPR1 with high affinity triggered CMKLR1 internalization and stimulated subsequent signal C-FOS expression and cAMP production. C-20, such as chemerin, showed CMKLR1-dependent chemotactic property. Furthermore, in primary Leydig cells and antral follicles, C-20 showed similar but less potent suppressive effect on human chorionic gonadotropin-stimulated testosterone production and progesterone production, compared with chemerin.

Conclusion: The novel chemerin-derived C-20 peptide binds to chemerin receptors CMKLR1 and GPR1 and showed similar but less potent bioactivity in chemotaxis and the suppression of gonadal steroidogenesis, suggesting that after optimization, C-20 is possible to be a useful experimental tool for the understanding of the biological functions of chemerin/CMKLR1 and chemerin/GPR1 signaling.