Towards the convergent therapeutic potential of G protein-coupled receptors in autism spectrum disorders

Autism spectrum disorders (ASDs) are diagnosed in 1/100 children worldwide, based on two core symptoms: deficits in social interaction and communication, and stereotyped behaviours. G protein-coupled receptors (GPCRs) are the largest family of cell-surface receptors that transduce extracellular signals to convergent intracellular signalling and downstream cellular responses that are commonly dysregulated in ASD. Despite hundreds of GPCRs being expressed in the brain, only 23 are genetically associated with ASD according to the Simons Foundation Autism Research Initiative (SFARI) gene database: oxytocin OTR; vasopressin V1A and V1B; metabotropic glutamate mGlu5 and mGlu7; GABAB2; dopamine D1, D2 and D3; serotoninergic 5-HT1B; & beta;2-adrenoceptor; cholinergic M3; adenosine A2A and A3; angiotensin AT2; cannabinoid CB1; chemokine CX3CR1; orphan GPR37 and GPR85; and olfactory OR1C1, OR2M4, OR2T10 and OR52M1. Here, we review the therapeutic potential of these 23 GPCRs, as well as 5-HT2A and 5-HT7, for ASD. For each GPCR, we discuss its genetic association, genetic and pharmacological manipulation in animal models, pharmacopoeia for core symptoms of ASD and rank them based on these factors. Among these GPCRs, we highlight D2, 5-HT2A, CB1, OTR and V1A as the more promising targets for ASD. We discuss that the dysregulation of GPCRs and their signalling is a convergent pathological mechanism of ASD. Their therapeutic potential has only begun as multiple GPCRs could mitigate ASD.