R3(BDelta23 27)R/I5 chimeric peptide, a selective antagonist for GPCR135 and GPCR142 over relaxin receptor LGR7: in vitro and in vivo characterization.
Both relaxin-3 and its receptor (GPCR135) are expressed predominantly in brain regions known to play important roles in processing sensory signals. Recent studies have shown that relaxin-3 is involved in the regulation of stress and feeding behaviors. The mechanisms underlying the involvement of relaxin-3/GPCR135 in the regulation of stress, feeding, and other potential functions remain to be studied. Because relaxin-3 also activates the relaxin receptor (LGR7), which is also expressed in the brain, selective GPCR135 agonists and antagonists are crucial to the study of the physiological functions of relaxin-3 and GPCR135 in vivo. Previously, we reported the creation of a selective GPCR135 agonist (a chimeric relaxin-3/INSL5 peptide designated R3/I5). In this report, we describe the creation of a high affinity antagonist for GPCR135 and GPCR142 over LGR7. This GPCR135 antagonist, R3(BDelta23-27)R/I5, consists of the relaxin-3 B-chain with a replacement of Gly23 to Arg, a truncation at the C terminus (Gly24-Trp27 deleted), and the A-chain of INSL5. In vitro pharmacological studies showed that R3(BDelta23-27)R/I5 binds to human GPCR135 (IC50=0.67 nM) and GPCR142 (IC50=2.29 nM) with high affinity and is a potent functional GPCR135 antagonist (pA2=9.15) but is not a human LGR7 ligand. Furthermore, R3(BDelta23-27)R/I5 had a similar binding profile at the rat GPCR135 receptor (IC50=0.25 nM, pA2=9.6) and lacked affinity for the rat LGR7 receptor. When administered to rats intracerebroventricularly, R3(BDelta23-27)R/I5 blocked food intake induced by the GPCR135 selective agonist R3/I5. Thus, R3(BDelta23-27)R/I5 should prove a useful tool for the further delineation of the functions of the relaxin-3/GPCR135 system.
Kuei
Chester
C
Johnson & Johnson Pharmaceutical Research and Development, LLC, San Diego, California 92121, USA.
Sutton
Steven
S
Bonaventure
Pascal
P
Pudiak
Cindy
C
Shelton
Jonathan
J
Zhu
Jessica
J
Nepomuceno
Diane
D
Wu
Jiejun
J
Chen
Jingcai
J
Kamme
Fredrik
F
Seierstad
Mark
M
Hack
Michael D
MD
Bathgate
Ross A D
RA
Hossain
Mohammed Akhter
MA
Wade
John D
JD
Atack
John
J
Lovenberg
Timothy W
TW
Liu
Changlu
C
D000818:Animals; D001921:Brain / Q000378:metabolism; D019556:COS Cells; D002522:Chlorocebus aethiops; D006801:Humans; D007328:Insulin / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D008565:Membrane Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009475:Neurons, Afferent / Q000378:metabolism; D011485:Protein Binding / Q000235:genetics; D017433:Protein Structure, Secondary / Q000235:genetics; D011506:Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors* / Q000378:metabolism; D018000:Receptors, Peptide / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology*; D012065:Relaxin / Q000031:analogs & derivatives* / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects
D007328:Insulin; C084797:Leydig insulin-like protein; D008565:Membrane Proteins; D011506:Proteins; C480238:RLN3 protein, human; C417543:RXFP1 protein, human; C410092:RXFP3 protein, human; C480239:RXFP4 protein, human; D043562:Receptors, G-Protein-Coupled; D018000:Receptors, Peptide; D011993:Recombinant Fusion Proteins; C504789:Rxfp1 protein, rat; D012065:Relaxin