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N‐terminal alterations turn the gut hormone GLP‐2 into an antagonist with gradual loss of GLP‐2 receptor selectivity towards more GLP‐1 receptor interaction
Author(s) -
Gabe Maria Buur Nordskov,
Gasbjerg Lærke Smidt,
Gadgaard Sarina,
Lindquist Peter,
Holst Jens Juul,
Rosenkilde Mette Marie
Publication year - 2022
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/bph.15866
Subject(s) - glucagon like peptide 1 receptor , receptor , antagonism , endocrinology , medicine , antagonist , glucagon like peptide 1 , receptor antagonist , chemistry , hek 293 cells , pharmacology , biology , agonist , type 2 diabetes , diabetes mellitus
Background and Purpose To fully elucidate the regulatory role of the GLP‐2 system in the gut and the bones, potent and selective GLP‐2 receptor (GLP‐2R) antagonists are needed. Searching for antagonist activity, we performed systematic N‐terminal truncations of human GLP‐2(1‐33). Experimental Approach COS‐7 cells were transfected with the human GLP‐2R and assessed for cAMP accumulation or competition binding using 125 I‐GLP‐2(1‐33)[M10Y]. To examine selectivity, COS‐7 cells expressing human GLP‐1 or GIP receptors were assessed for cAMP accumulation. Key Results Affinity of the N‐terminally truncated GLP‐2 peptides for the GLP‐2 receptor decreased with reduced N‐terminal peptide length (K i 6.5–871 nM), while increasing antagonism appeared with inhibitory potencies (IC 50 ) values from 79 to 204 nM for truncation up to GLP‐2(4‐33) and then declined. In contrast, truncation‐dependent increases in intrinsic activity were observed from an E max of only 20% for GLP‐(2‐33) up to 46% for GLP‐2(6‐33) at 1 μM, followed by a decline. GLP‐2(9‐33) had the highest intrinsic efficacy (E max 65%) and no antagonistic properties. Moreover, with truncations up to GLP‐2(8‐33), a gradual loss in selectivity for the GLP‐2 receptor appeared with increasing GLP‐1 receptor (GLP‐1R) inhibition (up to 73% at 1 μM). Lipidation of the peptides improved antagonism (IC 50 down to 7.9 nM) for both the GLP‐2 and the GLP‐1R. Conclusion and Implications The N‐terminus of GLP‐2 is crucial for GLP‐2R activity and selectivity. Our observations form the basis for the development of tool compounds for further characterization of the GLP‐2 system.