Sphingosine-1-phosphate receptor 3 activation promotes sociability and regulates the expression of genes associated with anxiolytic-like behavior

We previously demonstrated that sphingosine-1-phosphate receptor 3 (S1PR3) in the medial prefrontal cortex (mPFC) prevents stress-mediated reductions in sociability. S1PR3 is a ubiquitously expressed G-protein coupled receptor that regulates immune system function, although its regulation of other biological processes is not well understood. Pharmacological activators of S1PR3 might provide important insights for understanding the neural substrates underlying sociability and/or serve as novel, preclinical treatments for social anxiety. Here we show that in mice, systemic injections of an S1PR3-specific agonist, CYM5541, promotes sociability in males and females whereas an S1PR3-specific antagonist, CAY10444, increases amygdala activation and promotes social anxiety-like behavior in females. S1PR3 expression is increased in the mPFC and dentate gyrus of females compared to males. RNA sequencing in the mPFC reveals that S1PR3 activation alters the expression of transcripts related to immune function, neurotransmission, transmembrane ion transport, and intracellular signaling. This work provides evidence that S1PR3 agonists, which have classically been used as immune modulators, might also be used as novel anxiolytics. S1PR3 might be an important hub gene for anxiolytic effects as it reduces inflammatory processes caused by stress and increases transcripts linked to anxiolytic neurotransmission.