Stimulus bias exhibited by ligands relative to the reference agonist GLP-1(7–36)NH2
Data were analyzed using an operational model of agonism as defined in eq. 4 to estimate log τc/KA ratios. Changes in log τc/KA ratios were calculated to provide a measure of the degree of stimulus bias exhibited between different signaling pathways relative to that of the reference agonist (GLP-1(7–36)NH2). Values are expressed as means ± S.E.M. of three to five independent experiments conducted in duplicate. Data were analyzed with one-way analysis of variance and Dunnett’s post test.
| Pathway 1: Pathway 2 | Ligand | |||||||
|---|---|---|---|---|---|---|---|---|
| GLP-1(7–36)NH2 | BMS21 | Boc5 | TT15 | BETP | Compound 2 | |||
| pERK1/2: | cAMP | 0 ± 0.11 (1) | 0.83 ± 0.34 (6.7) | 1.77 ± 0.49* (59) | 1.45 ± 0.55 (28) | 1.09 ± 0.60 (12) | 1.05 ± 0.43 (11) | |
| iCa2+ | 0 ± 0.10 (1) | 0.28 ± 0.36 (1.9) | -0.22 ± 0.56 (0.6) | ND | –1.23 ± 0.44 (0.06) | ND | ||
| β-Arr1 | 0 ± 0.09 (1) | ND | ND | ND | –1.39 ± 0.46 (0.04)* | 0.22 ± 0.46 (1.7) | ||
| β-Arr2 | 0 ± 0.11 (1) | ND | ND | ND | –1.97 ± 0.46 (0.01)* | –0.08 ± 0.44 (0.83) | ||
| iCa: | cAMP | 0 ± 0.14 (1) | 0.60 ± 0.37 (3.9) | 0.52 ± 0.28 (3.3) | ND | 1.74 ± 0.42 (55)* | ND | |
| pERK1/2 | 0 ± 0.10 (1) | –0.28 ± 0.36 (0.53) | 0.22 ± 0.56 (1.6) | ND | 1.23 ± 0.44 (20) | ND | ||
| β-Arr1 | 0 ± 0.08 (1) | ND | ND | ND | −0.16 ± 0.16 (0.70) | ND | ||
| β-Arr2 | 0 ± 0.14 (1) | ND | ND | ND | −1.22 ± 0.16 (0.06)* | ND | ||
| β-Arr1: | cAMP | 0 ± 0.09 (1) | ND | ND | ND | 2.38 ± 0.43 (239)* | 1.73 ± 0.22 (54)* | |
| pERK1/2 | 0 ± 0.09 (1) | ND | ND | ND | 1.39 ± 0.46 (24)* | −0.22 ± 0.46 (0.61) | ||
| iCa2+ | 0 ± 0.08 (1) | ND | ND | ND | 0.16 ± 0.16 (1.43) | ND | ||
| β-Arr2 | 0 ± 0.10 (1) | ND | ND | ND | −0.58 ± 0.19 (0.26) | −0.3 ± 0.24 (0.50) | ||
| β-Arr2: | cAMP | 0 ± 0.11 (1) | ND | ND | ND | 2.96 ± 0.43 (918)* | 2.03 ± 0.17 (108)* | |
| pERK1/2 | 0 ± 0.11 (1) | ND | ND | ND | 1.97 ± 0.46 (93)* | 0.08 ± 0.44 (1.2) | ||
| iCa2+ | 0 ± 0.16 (1) | ND | ND | ND | 1.22 ± 0.16 (17)* | ND | ||
| β-Arr1 | 0 ± 0.10 (1) | ND | ND | ND | 0.58 ± 0.19 (3.8) | 0.3 ± 0.24 (2.0) | ||
β-Arr, beta arrestin; BETP, 4-(3-benzyloxyphenyl)-2-ethylsulfinyl-6-(trifluoromethyl)pyrimidine; Boc5, 1,3-bis [[4-(tert-butoxy-carbonylamino)benzoyl]amino]-2,4-bis[3-methoxy-4-(thiophene-2-carbonyloxy)-phenyl]cyclobutane-1,3-dicarboxylic acid; Compound 2, 6.7-dichloro-2-methylsulfonyl-3-tert-butylaminoquinoxaline; ERK1/2, extracellular signal-related kinases 1 and 2; iCa2+, intracellular calcium; ND, not defined; TT15, (2S)-2-[[(8S)-7-benzoyl-3-[4-[(3,4-dichlorophenyl)methoxy]phenyl]-2-oxo-1,6,8,9-tetrahydropyrido[4,3-g][1,4]benzoxazine-8-carbonyl]amino]-3-[4-(4-cyanophenyl)phenyl]propanoic acid.
↵* P < 0.05.