Table 3. In vitro signalling assays used in MOR drug discovery.
| Compound | Response | Cell type | Assays | References |
|---|---|---|---|---|
| TRV130 (Oliceridine) | β-Arrestin recruitment Nb33 recruitment mGsi recruitment G protein activation GIRK/VGC channel modulation Inhibition of Fsk-induced cAMP accumulation Internalisation MOPr phosphorylation |
HEK293 | DiscoverX PathHunter, BRET, FRET BRET BRET BRET, FRET Membrane potential assay, patch-clamp electrophysiology cAMP HiRange Kit, BRET, GloSensor DiscoverX PathHunterBRET, TR-FRET, imaging Western blot |
(DeWire et al., 2013, Gillis, Gondin, et al., 2020, Pedersen et al., 2020, Mori et al., 2021, Ehrlich et al., 2019, Yudin et al., 2019) |
| TRV0109101 | β-Arrestin recruitment Inhibition of Fsk-induced cAMP accumulation Internalisation MOPr phosphorylation |
HEK293 | DiscoverX PathHunter cAMP HiRange Kit DiscoverX PathHunter pSer375 Western blot |
(Koblish et al., 2017) |
| PZM21 | β-Arrestin recruitment Nb33 recruitment mGsi recruitment G protein activation GIRK/VGC channel modulation Calcium release Inhibition of Fsk-induced cAMP accumulation Internalisation MOPr phosphorylation |
HEK293 | DiscoverX PathHunter, BRET, FRET BRET BRET BRET, GTPγS binding, FRET Membrane potential assay, patch-clamp electrophysiology FLIPR (Fluo-4 dye) BRET, GloSensor DiscoverX PathHunterBRET Western blot |
(Manglik et al., 2016) (Gillis, Gondin, et al., 2020) (Hill et al., 2018) (Yudin et al., 2019) |
| SR-17018 | β-Arrestin recruitment Nb33 recruitment mGsi recruitment G protein activation GIRK channel activation Inhibition of Fsk-induced cAMP accumulation Internalisation MOPr phosphorylation |
CHO-K1, U2OS, HEK293 | DiscoverX PathHunter, BRET, FRET, imaging BRET BRET BRET, GTPγS binding Membrane potential assay BRET, cAMP HiRange Kit BRET, imaging Western blot |
(Grim et al., 2020; Schmid et al., 2017) (Gillis, Gondin, et al., 2020) |
| Mitragynine | G protein activation β-Arrestin recruitment |
CHO | GTPγS binding DiscoverX PathHunter |
(Varadi et al., 2016) (Wilson et al., 2021) |
| 7-OH Mitragynine | G protein activation β-Arrestin recruitment |
CHO | GTPγS binding DiscoverX PathHunter |
(Varadi et al., 2016) |
| Mitragynine Pseudoindoxyl | G protein activation β-Arrestin recruitment |
CHO | GTPγS binding DiscoverX PathHunter |
(Varadi et al., 2016) |
| Tianeptine | G protein activation Inhibition of Fsk-induced cAMP accumulation |
HEK293T | BRET BRET |
(Gassaway et al., 2014) |
| MP-1208&MP1207 | β-Arrestin recruitment G protein activation Inhibition of Fsk-induced cAMP accumulation |
HEK293, HTLA | Tango, BRET BRET, GTPγS binding GloSensor |
(Uprety et al., 2021) |
| CYM51010 | β-Arrestin recruitment G protein activation |
U2OS |
DiscoverX PathHunter BRET, GTPγS binding |
(Gomes et al., 2013) (Faouzi et al., 2020) |
| MP135 | β-Arrestin recruitment G protein activation |
U2OS | DiscoverX PathHunter BRET, GTPγS binding |
(Faouzi et al., 2020) |
Summary of the cell signalling assays commonly used for opioid drug discovery. Fsk; forskolin, ORs; opioid receptors, BRET: Bioluminescence Resonance Energy Transfer, FRET; Förster Resonance Energy Transfer, TR-FRET; Time-Resolve FRET; GIRK channel, G protein inwardly rectifying channel; VGCC, voltage-gated calcium channel.