Adgrd1 deficiency reveals increased hippocampal vulnerability and selective behavioral alterations in mice
ADGRD1 (GPR133) is an orphan adhesion G protein-coupled receptor (aGPCR) that primarily signals through Gs to regulate intracellular cAMP levels and is increasingly recognized for its roles across multiple tissues, including the central nervous system. Its conserved expression in neural tissues, the presence of splice variants in the fetal brain, and its structural similarity to other aGPCRs all suggest that it might play important roles in the organization of neural circuits. Recent studies have identified a wide range of extracellular, membrane- associated, and intracellular interacting partners, highlighting the receptors ability to integrate diverse signals. In this study, we explored the consequences of Adgrd1 deficiency in mice using behavioral, electrophysiological, and transcriptomic approaches. Adgrd1-null mice showed reduced nest-building behavior and decreased exploratory drive, while motor coordination and recognition memory remained largely intact. Electrophysiological recordings indicated a trend toward impaired long-term potentiation. These mice also exhibit increased susceptibility to kainate-induced excitotoxicity. RNA-seq analysis revealed coordinated changes in genes associated with inhibitory signaling, extracellular matrix organization, and cytoskeletal regulation, pointing to a shift toward reduced synaptic stabilization and increased hippocampal vulnerability. Altogether, these results suggest that Adgrd1 plays a key role in maintaining hippocampal resilience and regulating motivational behaviors through integrated molecular and circuit-level mechanisms.