β-Arrestin-2-Dependent Mechanism of GPR52 Signaling in Frontal Cortical Neurons

Abstract

The orphan Gαs-coupled receptor GPR52 is expressed exclusively in the brain, predominantly in circuitry relating to symptoms of neuropsychiatric and cognitive disorders such as schizophrenia. While GPR52 agonists have displayed antipsychotic and procognitive efficacy in murine models, there remains limited evidence delineating the molecular mechanisms of these effects. Indeed, previous studies have solely reported canonical cAMP signaling and CREB phosphorylation downstream of GPR52 activation. In the present study, we demonstrated that the synthetic GPR52 agonist, 3-BTBZ, equipotently induces cAMP accumulation, ERK1/2 phosphorylation, and β-arrestin-1 and -2 recruitment in transfected HEK293T cells. In cultured frontal cortical neurons, however, 3-BTBZ-induced ERK1/2 phosphorylation was significantly more potent than cAMP signaling, with a more prolonged signaling profile than that in HEK293T cells. Furthermore, knock down of β-arrestin-2 in frontal cortical neurons abolished 3-BTBZ-induced ERK1/2 phosphorylation, but not cAMP accumulation. These results suggest a β-arrestin-2-dependent mechanism for GPR52-mediated ERK1/2 signaling, which may link to cognitive function in vivo. Finally, these findings highlight the context-dependence of GPCR signaling in recombinant cells and neurons, offering new insights into translationally relevant GPR52 signaling mechanisms.

GPR52 Accelerates Fatty Acid Biosynthesis in a Ligand-Dependent Manner in Hepatocytes and in Response to Excessive Fat Intake in Mice

“…In contrast, Setoh et al identified another GPR52 agonist, compound 7m, and found that it dose dependently increased [cAMP] i concentrations in CHO cells expressing GPR52 (Setoh et al, 2014). The cAMPincreasing effect of c11 in HEK293 cells expressing GPR52 in our present study was consistent with the result by Setoh et al In addition, recent studies found that 3-BTBZ, another agonist of GPR52, potently increased [cAMP] i in a b-arrestin 2 independent manner in frontal cortical neurons (Hatzipantelis et al, 2020).…”

A Novel Antagonist Peptide Reveals a Physiological Role of Insulin-Like Peptide 5 in Control of Colorectal Function

“…Cells were assayed before and after addition of ligands or vehicle. Ligand-induced BRET was calculated by subtracting the ratio of emission through the acceptor wavelength window over emission through the donor wavelength window for a vehicle-treated cell sample from the same ratio for a second aliquot of the same cells treated with ligand(s) where both ratios were corrected by subtracting the baseline value prior to addition of vehicle or ligand . Data are representative of at least three experiments performed in duplicate and are analyzed using GraphPad Prism 9.…”

Exploring orphan GPCRs in neurodegenerative diseases

“…Prefrontal cortex Basal ganglia Striatonig 1q25.1 Gαs (Lin et al, 2020) PKA CREB ERK1/2 β-arrestin-2-dependent (Wang et al, 2020a;Hatzipantelis et al, 2020b) Agonists Derivative 17 (Nakahata et al, 2018) Compound 7a: 3-[2-(3-Chloro-5fluorobenzyl)-1-benzothiophen-7yl]-N-(2-ethoxyethyl)benzamide (Setoh et al, 2014) GPR55 central nerve tissues and cells 2q37.1 MAPK/ERK (PI3K)/Akt RhoA-dependent Ca2+ signaling NFAT (Henstridge et al, 2008) Gα12/13-RhoA-ROCK and Gαq-PLC-PKC(88) Gq-G11, mitogenactivated protein kinase 1, and calcium signaling (Henstridge et al, 2008;Andradas et al, 2011) anandamide 2-arachidonoylglycerol 2-arachidonoylglycerolphosphoinositol lysophosphatidylinositol N-palmitoylethanolamine (Ryberg et al, 2007) 2-arachidonoylglycerol N-palmitoylethanolamine JWH015 O-1602 (Ryberg et al, 2007)*…”