Blocking Two-Pore Domain Potassium Channel TREK-1 Inhibits the Activation of A1-Like Reactive Astrocyte Through the NF-κB Signaling Pathway in a Rat Model of Major Depressive Disorder

Abstract

Major depressive disorder (MDD) refers to a widespread psychiatric disorder. Astrocytes play a pivotal role in regulating inflammation which is a well-acknowledged key component in depression pathogenesis. However, the effects of the neuroinflammation-inducing A1-like astrocytes on MDD are still unknown. TWIK-related K+ channel 1 (TREK-1) has been demonstrated to regulate the action of antidepressants. Nevertheless, its mechanisms and effects on A1-like astrocyte stimulation in MDD are not clear. Therefore, we conducted in vivo and in vitro experiments using TREK-1 specific inhibitor spadin. In vivo, rats were subjected to a 6-week chronic unpredictable mild stress (CUMS) followed by spadin treatment. Behavioral tests were employed to surveil depressive-like behaviors. Hippocampal proteomic analysis was carried out with the purpose of identifying differentially expressed proteins after CUMS and spadin treatments. In vitro, astrocyte-conditioned medium and spadin were used to treat rat astrocyte cell line. The activated microglia, inflammatory factors, A1 astrocyte markers, and activated nuclear factor kappa B (NF-κB) pathway were later analyzed using immunofluorescence, western blot, and RT-qPCR. Our findings indicated that blockage of TREK-1 reduced CUMS-induced depressive-like behavior in rats, inhibited the microglial stimulation, reduced inflammatory factor levels, and suppressed the activation of A1-like reactive astrocytes in the hippocampus. We also verified that the suppression of A1-like astrocytes by spadin necessitated the NF-κB pathway. According to the findings, blocking TREK-1 inhibited the activation of A1-like reactive astrocytes via the NF-κB signaling pathway in MDD. Our study preliminarily identifies a novel antidepressant mechanism of TREK-1 action and provides a therapeutic path for MDD.