Low-dose mixtures of dietary nutrients ameliorate behavioral deficits in multiple mouse models of autism

Autism spectrum disorder (ASD) is a group of heterogeneous, behaviorally defined neurodevelopmental conditions influenced by both genetic and environmental factors. Here, we show that supplementation of multiple low-dose nutrients-an important environmental factor contributing to ASD-can modulate synaptic proteomes, reconfigure neural ensembles, and improve social behaviors in mice. First, we used Tbr1+/- mice, a well-established model of ASD, to investigate the effect of nutrient cocktails containing zinc, branched-chain amino acids (BCAA), and serine, all of which are known to regulate synapse formation and activity. Supplementation of nutrient cocktails for 7 days altered total proteomes by increasing synapse-related proteins. Our results further reveal that Tbr1 haploinsufficiency promotes hyperactivation and hyperconnectivity of basolateral amygdala (BLA) neurons, enhancing the activity correlation between individual neurons and their corresponding ensembles. Nutrient supplementation normalized the activity and connectivity of the BLA neurons in Tbr1+/- mice during social interactions. We further show that although a low dose of individual nutrients did not alter social behaviors, treatment with supplement mixtures containing low-dose individual nutrients improved social behaviors and associative memory of Tbr1+/- mice, implying a synergistic effect of combining low-dose zinc, BCAA, and serine. Moreover, the supplement cocktails also improved social behaviors in Nf1+/- and Cttnbp2+/M120I mice, two additional ASD mouse models. Thus, our findings reveal aberrant neural connectivity in the BLA of Tbr1+/- mice and indicate that dietary supplementation with zinc, BCAA, and/or serine offers a safe and accessible approach to mitigate neural connectivity and social behaviors across multiple ASD models.