Placental tryptophan metabolism as a potential novel pathway for the developmental origins of mental diseases

Abstract

Dysfunction of brain serotonin (5-HT) signaling contributes to the pathophysiology of several psychiatric disorders. However, before 5-HT acts as a neurotransmitter/neuromodulator in the adult brain, increasing evidence suggests that it plays crucial roles in the modulation of essential neurodevelopmental processes. It was recently demonstrated that the placenta synthesizes 5-HT from maternally derived tryptophan during pregnancy. Therefore, genetic and environmental perturbations that affect placental tryptophan metabolism could alter neurodevelopmental processes in the developing embryo, and contribute to the developmental origin of psychiatric disorders. Here we discuss how disruptions of the placental tryptophan metabolic pathway may lead to abnormal brain development and function in adult life.