Sex-dependent role of CD300f immune receptor in generalized anxiety disorder.

Generalized Anxiety Disorder (GAD) presents a high prevalence in the population, leading to distress and disability. Immune system alterations have been associated with anxiety-related behaviors in rodents and GAD patients. CD300f immune receptors are highly expressed in microglia and participate not only in the modulation of immune responses but also in pruning and reshaping synapses. It was recently demonstrated that CD300f might be influential in the pathogenesis of depression in a sex-dependent manner. Here, we evaluated the role of CD300f immune receptor in anxiety, using CD300f knockout mice (CD300f-/-) and patients with GAD. We observed that male CD300f-/- mice had numerous behavioral changes associated with a low-anxiety phenotype, including increased open field central locomotion and rearing behaviors, more exploration in the open arms of the elevated plus-maze test, and decreased latency to eat in the novelty suppressed feeding test. In a cross-sectional population-based study, including 1111 subjects, we evaluated a common single-nucleotide polymorphism rs2034310 (C/T) in the cytoplasmatic tail of CD300f gene in individuals with GAD. Notably, we observed that the T allele of the rs2034310 polymorphism conferred protection against GAD in men, even after adjusting for confounding variables. Overall, our data demonstrate that CD300f immune receptors are involved in the modulation of pathological anxiety behaviors in a sex-dependent manner. The biological basis of these sex differences is still poorly understood, but it may provide significant clues regarding the neuropathophysiological mechanisms of GAD and can pave the way for future specific pharmacological interventions.