Optogenetic Control of Motor Coordination by Gi/o Protein-coupled Vertebrate Rhodopsin in Cerebellar Purkinje Cells

Davina V Gutierrez,Takashi Maejima,Wolfgang Kruse,Olivia Masseck,Denise Kuckelsberg,Robert A Hyde,Stefan Herlitze,Martin Krause,Melanie D Mark

doi:10.1074/jbc.m111.253674

Davina V Gutierrez, Takashi Maejima + Show 7 more

Open Access

https://doi.org/10.1074/jbc.m111.253674

Copy DOI

Abstract

G protein-coupled receptors are involved in the modulation of complex neuronal networks in the brain. To investigate the impact of a cell-specific G(i/o) protein-mediated signaling pathway on brain function, we created a new optogenetic mouse model in which the G(i/o) protein-coupled receptor vertebrate rhodopsin can be cell-specifically expressed with the aid of Cre recombinase. Here we use this mouse model to study the functional impact of G(i/o) modulation in cerebellar Purkinje cells (PCs). We show that in vivo light activation of vertebrate rhodopsin specifically expressed in PCs reduces simple spike firing that is comparable with the reduction in firing observed for the activation of cerebellar G(i/o)-coupled GABA(B) receptors. Notably, the light exposure of the cerebellar vermis in freely moving mice changes the motor behavior. Thus, our studies directly demonstrate that spike modulation via G(i/o)-mediated signaling in cerebellar PCs affects motor coordination and show a new promising approach for studying the physiological function of G protein-coupled receptor-mediated signaling in a cell type-specific manner.

Highlights

Kϩ channel and voltage-gated Ca2ϩ channels via pertussis toxin-sensitive Gi/o protein-mediated signaling [3]
The exact mechanism in which Gi/o-mediated GPCR modulation may occur within Purkinje cells (PCs) and how such modulation may influence the single spike pattern and motor coordination has been difficult to address in vivo, as GABAB receptor (GABABR) and other Gi/o-coupled receptors are expressed in various cell types in the cerebellum and can only be activated by slowly diffusing drugs
The vRh-GFP is only expressed when Lac-Z is excised by Cre recombinases, whereas LacZ is present throughout the central nervous system (CNS) when Cre is not expressed (Fig. 1A) [14]

Summary

Introduction

Kϩ channel and voltage-gated Ca2ϩ channels via pertussis toxin-sensitive Gi/o protein-mediated signaling [3]. Creation of a New Optogenetic Mouse Line vRhGFP(TgflvRh-GFP) for the Controlled Expression of vRh in a Cell Type-specific Manner—To investigate the cell type-specific function of Gi/o pathway activation within neuronal networks in vivo and to analyze the functional impact of pathway activation on mouse behavior, we created transgenic mice to activate the Gi/o-coupled, light activated GPCR vRh by Cre recombinases.

Results

Conclusion