TY - JOUR

T1 - Structure–activity relationship of GPR15L peptide analogues and investigation of their interaction with the GPR15 receptor

AU - Deng, Yufang

AU - Perez Almeria, Claudia V.

AU - van Gijzel, Lieke

AU - Schaller, Kay

AU - Vedel, Line

AU - Gloriam, David E.

AU - Ulven, Trond

AU - Bräuner-Osborne, Hans

N1 - Funding Information: We thank Asmita Manandhar for performing chemical analyses on some of the synthesized peptides. This project is funded by the China Scholarship Council (Grant 201907940002 to Y.D.), the Novo Nordisk Foundation (Grants NNF17OC0028412 and NNF19OC0057730 to H.B.‐O.), the Carlsberg Foundation (Grant CF20‐0248 to H.B.‐O.), Lundbeck Foundation (Grant R163‐2013‐16327 to D.E.G.), European Research Council (Grant 639125 to D.E.G.) and Novo Nordisk A/S (STAR postdoc program grant to D.E.G.). Publisher Copyright: © 2023 The Authors. Basic & Clinical Pharmacology & Toxicology published by John Wiley & Sons Ltd on behalf of Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

PY - 2023

Y1 - 2023

N2 - The 57-mer full-length GPR15L(25-81) peptide has been identified as the principal endogenous agonist of the G protein-coupled receptor GPR15. Its main activity resides in the C-terminal 11-mer GPR15L(71-81), which has full efficacy but ~40-fold lower potency than the full-length peptide. Here, we systematically investigated the structure–activity relationship of GPR15L(71-81) by truncations/extensions, alanine-scanning, and N- and C-terminal capping. The synthesized peptide analogues were tested at GPR15 stably expressed in HEK293A cells using a homogenous time-resolved Förster resonance energy transfer-based Gi cAMP functional assay. We show that the C-terminal α carboxyl group and the residues Leu78, Pro75, Val74, and Trp72 are critical for receptor interaction and contribute significantly to the peptide potency. Furthermore, we tested the ability of GPR15L(71-81), C-terminally amidated GPR15L(71-81), and GPR15L(25-81) to activate the three GPR15 receptor mutants in a bioluminescence resonance energy transfer-based G protein activation assay. The results demonstrate that the Lys192 and Glu272 residues in GPR15 are important for the potency of the GPR15L peptide. Overall, our study identifies critical residues in the peptide and receptor sequences for future drug design.

AB - The 57-mer full-length GPR15L(25-81) peptide has been identified as the principal endogenous agonist of the G protein-coupled receptor GPR15. Its main activity resides in the C-terminal 11-mer GPR15L(71-81), which has full efficacy but ~40-fold lower potency than the full-length peptide. Here, we systematically investigated the structure–activity relationship of GPR15L(71-81) by truncations/extensions, alanine-scanning, and N- and C-terminal capping. The synthesized peptide analogues were tested at GPR15 stably expressed in HEK293A cells using a homogenous time-resolved Förster resonance energy transfer-based Gi cAMP functional assay. We show that the C-terminal α carboxyl group and the residues Leu78, Pro75, Val74, and Trp72 are critical for receptor interaction and contribute significantly to the peptide potency. Furthermore, we tested the ability of GPR15L(71-81), C-terminally amidated GPR15L(71-81), and GPR15L(25-81) to activate the three GPR15 receptor mutants in a bioluminescence resonance energy transfer-based G protein activation assay. The results demonstrate that the Lys192 and Glu272 residues in GPR15 are important for the potency of the GPR15L peptide. Overall, our study identifies critical residues in the peptide and receptor sequences for future drug design.

KW - agonist

KW - GPR15 receptor

KW - GPR15L peptide

KW - receptor mutagenesis

KW - structure–activity relationship

U2 - 10.1111/bcpt.13861

DO - 10.1111/bcpt.13861

M3 - Journal article

C2 - 36930875

AN - SCOPUS:85151936041

VL - 132

SP - 459

EP - 471

JO - Basic and Clinical Pharmacology and Toxicology

JF - Basic and Clinical Pharmacology and Toxicology

SN - 1742-7835

IS - 6

ER -