Journal Article

Dissecting GPCR Contributions to Gαo-Dependent Motor Dysfunction in GNAO1-Related Disorders Using Caenorhabditis elegans

Bessereau, Jean-Louis, Pannone, Luca, Venanzi, Serenella, Galosi, Serena, Milanetti, Edoardo, Di Rienzo, Lorenzo, Martire, Alberto, Follo, Francesca Carmen, Di Schiavi, Elia, Martinelli, Simone, Di Rocco, Martina, Leuzzi, Vincenzo, D’Alessandro, Manuela

2026

Overview

Background/Objectives: Pathogenic variants in GNAO1, encoding the inhibitory G protein subunit Gαo, cause severe neurodevelopmental disorders that remain largely refractory to pharmacological treatments. Gαo transduces inhibitory signals downstream of multiple G protein-coupled receptors (GPCRs) involved in motor control. Here, we used gene-edited Caenorhabditis elegans models carrying goa-1 variants, the ortholog of GNAO1, to investigate GPCR contributions to Gαo-dependent locomotor phenotypes. Methods: We combined pharmacological screening of dopamine- and cannabinoid-targeting ligands in goa-1 mutants with structural analysis of ligand-binding pocket conservation and genetic perturbation of receptor function using RNAi and knockout approaches. Results: Pharmacological modulation of GPCR signaling produced non-linear and context-dependent effects. Compounds predicted to further increase excitability may instead promote phenotypic improvement, consistent with compensatory network rebalancing. Structural analyses revealed substantial divergence in ligand-binding pocket conservation for several GPCR-ligand pairs, suggesting that altered binding affinity and selectivity may also contribute to the observed phenotypic outcome. Pharmacological experiments performed in GPCR-depleted mutants allowed for the correlation of structural findings with functional effects for selected receptor-ligand pairs. Finally, genetic reduction in GPCRs coupled to stimulatory G proteins ameliorated hyperactive locomotion in goa-1 mutants, whereas reduction in GPCRs coupled to inhibitory G proteins is largely insufficient to induce or exacerbate locomotor defects. Conclusions: Our findings identify excessive excitatory GPCR input as a key modulator of motor dysfunction in the context of impaired Gαo signaling. They also show that structural conservation is a necessary but not sufficient condition to predict functional responses. Overall, this study establishes C. elegans as a suitable platform to dissect GPCR-mediated signaling and highlights the value of integrating pharmacological and genetic approaches to guide target selection in GNAO1-related disorders.

• Publisher: MDPI AG,Multidisciplinary Digital Publishing Institute (MDPI)
• Subject: Adenosine / Analysis / Animals / Caenorhabditis elegans / Caffeine / Conservation / Dopamine / drug screening / Drug therapy / E coli / Ethanol / Excitability / G protein-coupled receptors / G proteins / Gene expression / GNAO1-related disorders / Gαo signaling / Ligands / Locomotion / Membrane proteins / Motor task performance / Movement disorders / Mutants / Nematodes / Neurodevelopmental disorders / Phenotypes / Proteins / RNA-mediated interference / Structure-function relationships / Worms