D1-mGlu5 heteromers mediate noncanonical dopamine signaling in Parkinson’s disease
Irene Sebastianutto, … , M. Angela Cenci, Julie Perroy
Irene Sebastianutto, … , M. Angela Cenci, Julie Perroy
Published February 10, 2020
Citation Information: J Clin Invest. 2020;130(3):1168-1184. https://doi.org/10.1172/JCI126361.
View: Text | PDF
Research Article Neuroscience

D1-mGlu5 heteromers mediate noncanonical dopamine signaling in Parkinson’s disease

Abstract

Dopamine receptor D1 modulates glutamatergic transmission in cortico-basal ganglia circuits and represents a major target of L-DOPA therapy in Parkinson’s disease. Here we show that D1 and metabotropic glutamate type 5 (mGlu5) receptors can form previously unknown heteromeric entities with distinctive functional properties. Interacting with Gq proteins, cell-surface D1-mGlu5 heteromers exacerbated PLC signaling and intracellular calcium release in response to either glutamate or dopamine. In rodent models of Parkinson’s disease, D1-mGlu5 nanocomplexes were strongly upregulated in the dopamine-denervated striatum, resulting in a synergistic activation of PLC signaling by D1 and mGlu5 receptor agonists. In turn, D1-mGlu5–dependent PLC signaling was causally linked with excessive activation of extracellular signal–regulated kinases in striatal neurons, leading to dyskinesia in animals treated with L-DOPA or D1 receptor agonists. The discovery of D1-mGlu5 functional heteromers mediating maladaptive molecular and motor responses in the dopamine-denervated striatum may prompt the development of new therapeutic principles for Parkinson’s disease.

Authors

Irene Sebastianutto, Elise Goyet, Laura Andreoli, Joan Font-Ingles, David Moreno-Delgado, Nathalie Bouquier, Céline Jahannault-Talignani, Enora Moutin, Luisa Di Menna, Natallia Maslava, Jean-Philippe Pin, Laurent Fagni, Ferdinando Nicoletti, Fabrice Ango, M. Angela Cenci, Julie Perroy

×

Figure 3

D1-mGlu5 heteromer favors Ca2+ signaling in vitro by enhancing basal activation and basal signaling of mGlu5 receptor.

Options: View larger image (or click on image) Download as PowerPoint
D1-mGlu5 heteromer favors Ca2+ signaling in vitro by enhancing basal act...
A TR-FRET–based sensor monitors mGlu5 receptor ECD conformation. (A) In the absence of ligand or in the presence of antagonist (LY341495), the proximity of TR-FRET donor and acceptor results in a high FRET signal. Agonist-induced (quisqualic acid [Quisq]) relative movement of the ECDs decreases the FRET signal (23). (B and C) Percentage of mGlu5 active conformation (B) with increasing amount of D1-Venus receptors in basal conditions (no ligand), with Quisq (10 μM) or with LY341495 (100 μM) (C) in the absence (blue) or presence (purple) of D1 receptor (corresponding to 279 ± 68 D1 fluorescence intensity [FI] on B) with increasing concentrations of Quisq (dark color) or LY341495 (light color). (D) mGlu5 basal activation when expressed alone (left), with D1 receptor (middle), or with D1 receptor and mGlu5Ctail as dominant negative peptide (right). *P < 0.05 vs. mGlu5 basal activation; #P < 0.05 vs. mGlu5 plus D1 receptor activation, unpaired t test (Mann-Whitney U test). Box and whiskers plots. (E) SNAP-mGlu5 and D1-Venus receptor expression levels were controlled by measurement of SNAP-Lumi4-Tb and Venus, respectively (FI). (F) Percentage of mGlu5-DelCtail active-conformation measured in absence (blue) or presence (purple) of D1 receptor with increasing concentrations of Quisq. (G) PLC activation is reported by new InsP production-induced decrease of HTRF signal between fluorescent-InsP and InsP-antibody (insert). (H) mGlu5-induced InsP production with increasing amount of D1 receptors in basal conditions (no ligand), with Quisq (10 μM), or with LY341495 (100 μM). InsP production was normalized to the maximal activity of mGlu5 in the presence of agonist. (I) Constitutive InsP production with increasing amount of mGlu5 receptor in absence (blue) or presence (purple) of a constant amount of D1 receptor (corresponding to 319 ± 4 D1 FI on H). Values are shown as mean ± SEM of 3 independent experiments.