Remimazolam Ameliorates Autistic-Like Behaviors via Suppression of Ferroptosis in VTA Dopaminergic Neurons in a Mouse Model of ASD.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, characterized by social dysfunction and stereotypic behavior, with the neuronal excitation/inhibition (E/I) imbalance as an underlying mechanism. The ultra-short-acting GABA-A receptor agonist remimazolam has elicited unexpected long-term improvements in agitation and cognition, suggesting a potential role in modulating the E/I imbalance. This study investigates the efficacy and mechanisms of remimazolam on ASD in a valproate (VPA)-induced model. Intraperitoneal administration of remimazolam significantly ameliorates autistic-like behaviors, with comparable effects caused by targeted injection of remimazolam into the ventral tegmental area (VTA). Chemogenetic inhibition of VTA dopaminergic neurons in VPA-exposed mice reverses the therapeutic effects of remimazolam. Conversely, remimazolam also ameliorate the autistic-like behaviors induced by chemogenetic inhibition. Remimazolam confers protection against VPA-induced injury to VTA dopaminergic neurons both in vivo and in vitro by inhibiting ferroptosis, as evidenced by the reversal of its key hallmarks: mitochondrial damage, iron overload and lipid peroxidation. Furthermore, ferroptosis agonists reverse the therapeutic effect of remimazolam and ferroptosis inhibitors alleviate the autistic-like behaviors. This study has demonstrated that remimazolam produces sustained alleviation of autistic-like behaviors by inhibiting ferroptosis, indicating that ferroptosis may be a critical mechanism to its protection of VTA dopaminergic neurons and resultant behavioral improvement.