Summary of affinity and cooperativity estimates for class C GPCR allosteric modulators binding to mGlu5 in HEK293A-mGlu5-low cells and cortical neurons, determined from [3H]methoxy-PEPy inhibition binding assays
Data represent the mean ± S.E.M. from the indicated number (n) of independent experiments performed in duplicate. pKB is the negative logarithm of the allosteric modulator equilibrium dissociation constant; logα is the logarithm of the cooperativity factor for the interaction between indicated ligands and [3H]methoxy-PEPy.
| Target Selectivitya | pKBb | Logα | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Ligand | Target | Target pKB | HEK293A-mGlu5-Low | n | Cortical Neurons | n | HEK293A-mGlu5-Low | Cortical Neurons | |
| VU0424465 | mGlu5 PAM-agonist | 8.27 | n.d. | 8.27 | 2 | 7.54 ± 0.42 | 6 | n.a. | −0.59 ± 0.14 |
| CPCCOEt | mGlu1 NAM | 5.31c | 2.2 | 4.90 ± 0.10 | 6 | 5.03 ± 0.37 | 3 | −0.54 ± 0.06 | −0.64 ± 0.07 |
| VU0483605 | mGlu1 PAM | 6.02 ± 0.14d | 0.35 | 6.48 ± 0.17 | 3 | n.d. | −0.17 ± 0.06 | n.d. | |
| BINA | mGlu2 PAM | 6.48e | 30 | 4.69 ± 0.25 | 6 | n.d. | n.a. | n.d. | |
| ML337 | mGlu3 NAM | 7.10e | 23 | 5.67 ± 0.22 | 3 | 6.29 ± 0.16 | 3 | −0.23 ± 0.07 | −0.23 ± 0.01 |
| PHCCC | mGlu4 PAM | 5.59e | 0.85 | 5.63 ± 0.11 | 6 | 6.23 ± 0.26 | 3 | −0.33 ± 0.03 | −0.46 ± 0.06 |
| AZ12216052 | mGlu8 PAM | 5.43 ± 0.12d | 0.81 | 5.38 ± 0.13 | 5 | 5.81 ± 0.09 | 3 | −0.38 ± 0.08 | −0.59 ± 0.09 |
| Cinacalcet | CaSR PAM | 6.39 ± 0.05c | 81 | 4.35 ± 0.10 | 6 | 5.12 ± 0.23 | 4 | n.a. | n.a. |
| NPS2143 | CaSR NAM | 6.66 ± 0.04c | 37 | 5.08 ± 0.02 | 3 | n.d. | −0.36 ± 0.09 | n.d. | |
| GS39783 | GABAB PAM | 4.68e | 0.08 | 6.27 ± 0.33 | 6 | n.d. | −0.18 ± 0.04 | n.d. | |
| CGP7930 | GABAB PAM | 4.48e | 0.63 | 4.78 ± 0.11 | 6 | 4.90 ± 0.29 | 3 | −0.34 ± 0.11 | −0.48 ± 0.08 |
n.a. denotes not applicable, as data were best fitted to a competitive model; n.d., not determined.
↵a Ratio of affinity for target relative to mGlu5, where a ratio <1 indicates greater affinity for mGlu5 than target receptor.
↵b Affinity values for cinacalcet, BINA, and VU0424465 (in HEK293A-mGlu5-low) are pKi.
↵c Literature-reported pKi estimate for CPCCOEt (Lavreysen et al., 2003) and pKB estimates for cinacalcet and NPS2143 (Leach et al., 2016).
↵d pKB estimates from analysis of iCa2+ mobilization curves in mGlu1 or mGlu8 expressing HEK293A cells (see Supplementary Fig. S2).
↵e pKB estimates generated from reanalysis of previously reported data (see Supplementary Fig. S2).