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.

injury is a major cause of death and disability after cardiac arrest (CA). Previous studies have shown that activating GABAB receptors significantly improves neurological function after CA, but the mechanism of this neuronal protection of damaged neurons remains unclear. Thus, the present study aimed to investigate whether GABAB receptor activation protects against neuronal injury and to reveal the underlying protective mechanisms. In this study, rats underwent 10 min of asphyxia to induce CA, and SH-SY5Y cells were subjected to oxygen and glucose deprivation/reoxygenation (OGD/R) to establish in vivo and in vitro models of hypoxic neuronal injury. Differential gene expression between CA rats and sham-operated rats was identified using RNA-seq. TUNEL and Nissl staining were used to evaluate cortical neuron damage, while Western blotting, qRT-PCR, and immunofluorescence assays were conducted to measure pyroptosis-related indicators. Furthermore, cellular models with high expression of caspase-11 were established to reveal the novel molecular mechanisms by which GABAB receptor activation exerts neuroprotective effects. Intriguingly, our results showed that caspase-11 and GSDMD were highly expressed in rats experiencing cardiac arrest. Specifically, GSDMD was expressed in neurons in the M1 area of the cerebral cortex. Moreover, activation of the GABAB receptor exerted a protective effect on neurons both in vivo and in vitro. Baclofen attenuated caspase-11 activation and neuronal pyroptosis after CA, and the anti-neuronal pyroptosis effect of baclofen was abolished by overexpression of caspase-11 in neuronal cells. In conclusion, GABAB receptor activation may play a neuroprotective role by alleviating neuronal pyroptosis through a mechanism involving caspase-11.& COPY; 2023 IBRO. Published by Elsevier Ltd. All rights reserved.

Between 30% and 50% of survivors of cardiac arrest (CA) suffer from cognitive deficits. However, no effective medical intervention is available to alleviate cognitive deficits. Baclofen is known to protect damaged neurons, but researchers have still not clearly whether baclofen alleviates CA-induced cognitive deficits. The present study aimed to investigate whether baclofen protects against post-CA cognitive deficits and to reveal the protective mechanism of baclofen. Rats underwent 10 min of asphyxia to establish CA models. Intriguingly, our results indicated that baclofen improved spatial memory 72 h after CA. Baclofen increased plasticity-related protein (PSD95, and GAP43) expression in the brain after CA. Baclofen reduced microglial number and the release of inflammatory factors (IL-1β and IL-18). Furthermore, baclofen significantly reduced the expression of pyroptosis-related molecules after CA. Notably, activation of NLRP3 abolished the anti-pyroptosis effect of baclofen and reduced the expression of synaptic plasticity-related proteins after CA. Taken together, this study first shows that baclofen attenuates cognitive deficits induced by brain injury after CA. The mechanism is at least partially attributed to baclofen regulating pyroptosis by inhibition of NLRP3 activation.

Background: Major depressive disorder (MDD) is a serious mental illness characterized by mood changes and high suicide rates. However, no studies are available to support a blood test method for MDD diagnosis. The objective of this research was to identify potential peripheral blood biomarkers for MDD and characterize the novel pathophysiology. Methods: We accessed whole blood microarray sequencing data for MDD and control samples from public databases. Biological functions were analysed by GO and KEGG pathway enrichment analyses using the clusterprofile R package. Infiltrated immune cell (IIC) proportions were identified using the CIBERSORT algorithm. Clustering was performed using the ConsensusClusterPlus R package. Protein–protein interactions (PPI) were assessed by constructing a PPI network using STRING and visualized using Cytoscape software. Rats were exposed to chronic unpredictable mild stress (CUMS) for 6 weeks to induce stress behaviour. Stress behaviour was evaluated by open field experiments and forced swimming tests. Flow cytometry was used to analyse the proportion of CD8 + T cells. The expression of the corresponding key genes was detected by qRT–PCR. Results: We divided MDD patients into CD8H and CD8L clusters. The functional enrichment of marker genes in the CD8H cluster indicated that autophagy-related terms and pathways were significantly enriched. Furthermore, we obtained 110 autophagy-related marker genes (ARMGs) in the CD8H cluster through intersection analysis. GO and KEGG analyses further showed that these ARMGs may regulate a variety of autophagy processes and be involved in the onset and advancement of MDD. Finally, 10 key ARMGs were identified through PPI analysis: RAB1A, GNAI3, VAMP7, RAB33B, MYC, LAMP2, RAB11A, HIF1A, KIF5B, and PTEN. In the CUMS model, flow cytometric analysis confirmed the above findings. qRT–PCR revealed significant decreases in the mRNA levels of Gnai3, Rab33b, Lamp2, and Kif5b in the CUMS groups. Conclusion: In this study, MDD was divided into two subtypes. We combined immune infiltrating CD8 + T cells with autophagy-related genes and screened a total of 10 ARMG genes. In particular, RAB1A, GNAI3, RAB33B, LAMP2, and KIF5B were first reported in MDD. These genes may offer new hope for the clinical diagnosis of MDD.

Brain-derived neurotrophic factor (BDNF) is a biomarker of depression. Recent studies have found adenosine deaminase acting on RNA1 (ADAR1) is a novel target being sensitive to stress at epigenetic level. The epigenetic regulation mechanism of stress-related depression is still unclear so far. To explore the potential regulating mechanism of ADAR1 on BDNF, over and low expression of ADAR1 in PC12 and SH-SY5Y cell lines are prepared. In the meanwhile, chronic unpredictable stress (CUS) mice are treated with ADAR1 inducer (interferon-γ, IFN-γ). ADAR1 regulates BDNF expression, which is proven by that over and low expressions of ADAR1 increase and decrease BDNF mRNA and protein respectively in vitro. Additionally, ADAR1 inducer alleviates the depressive-like behavior of CUS mice by recovering the decreased BDNF protein in brain and serum. Moreover, over and low expressions of ADAR1 reduce and enhance microRNA-432 (miR-432) expression respectively in vitro. Furtherly, over and low miR-432 expressions lead to decreased and increased BDNF and ADAR1 mRNA, protein and immunoreactivity respectively in vitro. The above results demonstrate that ADAR1 is involved in antidepressant action by regulating BDNF via miR-432. Those novel findings can provide a new idea for the study of epigenetic regulation mechanism, early diagnosis, and effective treatment of stress-related depression.

Brain injury is the leading cause of death and disability in survivors of cardiac arrest (CA). However, there is no effective medical intervention to alleviate brain injury. GABAB receptor activation is known to protect damaged neurons, but it is still unclear whether GABAB receptor activation alleviates CA-induced brain injury. The present study aimed to investigate whether GABAB receptor activation protects against post-CA brain injury and to reveal the protective mechanism of the GABAB receptor. Rats underwent 10-min asphyxia-induced CA and PC12 cells were subjected to oxygen and glucose deprivation/reoxygenation (OGD/R) to establish in vivo and in vitro models. We found that the post-CA brain injury led to neurobehavioral deficits and neuronal cell death by examining neurobehavioral tests and histopathological results. We confirmed the existence of pyroptosis in the post-CA brain injury. GABAB receptor activation by baclofen significantly recovered GABAB receptor expression and reduced neuronal cell death, and neurologic deficits showed improvements after CA. In addition, baclofen improved cell viability in cells exposed to OGD/R. In terms of the mechanism, baclofen alleviated the increased levels of DDX3X, NLRP3, caspase 1, GSDMD, and the proinflammatory cytokines IL-1β and IL-18 induced by CA. Further experiments showed that high expression of NLRP3 or DDX3X induced increased expression of pyroptosis-related molecules and decreased cell viability, eliminating the protective effect of GABAB receptor agonists on OGD/R cells. In conclusion, our data firstly demonstrate that GABAB receptor activation alleviates brain injury in response to CA by downregulating the DDX3X/NLRP3 pathway to prevent neuronal pyroptosis.

Adenosine deaminase acting on RNA1 (ADAR1) is a newly discovered epigenetic molecule marker that is sensitive to environmental stressors. A recent study has demonstrated that ADAR1 affects BDNF expression via miR-432 and is involved in antidepressant action. However, the detailed molecular mechanism is still unclear. We have uncovered a new molecular mechanism showing the involvement of miR-432 and circ_0000418 in mediating the antidepressant action of ADAR1. We demonstrate that the ADAR1 inducer (IFN-γ) alleviates the depressive-like behaviors of BALB/c mice treated with chronic unpredictable stress (CUS) exposure. Moreover, both in vivo and in vitro studies show that ADAR1 differently impacts miR-432 and circ_0000418 expressions. Furthermore, the in vitro results demonstrate that circ_0000418 oppositely affects BDNF expression. Together, our results indicate that ADAR1 affects CUS-induced depressive-like behavior and BDNF expression by acting on miR-432 and circ_0000418. Elucidation of this new molecular mechanism will not only provide insights into further understanding the important role of ADAR1 in stress-induced depressive-like behavior but also suggest a potential therapeutic strategy for developing novel anti-depressive drugs.

GABA B receptor (GABA B R) antagonists are known to have antidepressant effects. TWIK-related potassium channel-1 (TREK-1) plays a role in GABA B R signaling. However, the role of TREK-1 in the antidepressant actions of GABA B R antagonist is still unclear. This study aimed to investigate whether TREK-1 mediates the antidepressant actions of GABA B R antagonist. To investigate this hypothesis, chronic unpredictable stress rats were treated with a GABA B R antagonist, GABA B R agonist, or TREK-1 blocker. Depression-like behavior was assessed by open field tests and sucrose preference tests. GABA B R and TREK-1 protein levels were measured by western blotting. The results demonstrated that the GABA B R antagonist alleviated depression-like behavior and reversed the decrease in hippocampal TREK-1 protein expression that characterizes chronic unpredictable stress rats. Conversely, the GABA B R agonist exacerbated depression-like behavior and further decreased hippocampal TREK-1 protein expression. In addition, the TREK-1 blocker alleviated the depression-like behavior of chronic unpredictable stress rats and increased hippocampal TREK-1 protein expression. These results suggest that the alleviative effects of the GABA B receptor antagonist on depression-like behavior in chronic unpredictable stress rats are at least partially mediated through TREK-1. These novel findings will be helpful for the clinical therapy of depression.

Objective:To investigate the effect of adenosine deaminase acting on RNA 1 (ADAR1) on 5-serotonin-2c receptor in alleviating aggression in socially isolated mice.Methods:Sixty healthy male BALB / c mice aged 21 days were randomly divided into six groups: social isolation group, social control group, ADAR1 inducer social isolation group, ADAR1 inhibitor social isolation group, ADAR1 inducer social control group and ADAR1 inhibitor control group.The mice fed in single cage for 4 weeks were used as social isolation model while the mice fed in group were used as control group.ADAR1 inducer (5.0×10 4 U/kg) and inhibitor (10 mg/kg) were given intraperitoneally to mice in the ADAR1 inducer social isolation group and the ADAR1 inhibitor social isolation group respectively.The aggressive behavior of mice was evaluated by resident-intruder test.The expression of ADAR1 and 5-serotonin-2c receptors in the brain of mice was detected by immunohistochemistry and Western blot. Results:The attack latency of social isolation group was significantly lower than that of social control group ((43.15±6.99) s, (542.40±30.50) s; t=15.906, P<0.01), and the latency of attack ((256.70±29.49) s) in the ADAR1 inducer social isolation group was significantly higher than that in the social isolation group ( t=7.046, P<0.01). The latency of attack ((15.25±2.18)s) in the ADAR1 inhibitor social isolation group was significantly lower than that in the social isolation group ( t=3.809, P<0.01). The optical density of ADAR1 immunoreactive cells in the amygdala of the social isolation group mice was significantly lower than that in the corresponding brain area of the social control group (BLA: (0.038±0.002), (0.074±0.004); LaDL: (0.033±0.002), (0.060±0.002); LaVM: (0.045±0.003), (0.073±0.004); Lavl area: (0.044±0.003), (0.070±0.003); t=8.428, 9.037, 6.462, 5.698, all P<0.01). The optical density of ADAR1 immunoreactive positive cells in the amygdala (BLA: (0.060±0.003), LaDL: (0.042±0.002), LaVM: (0.056±0.004), Lavl: (0.054±0.003) in the ADAR1 inducer social isolation group was significantly higher than those in the corresponding brain area of the social isolation group mice ( t=6.055, 2.876, 2.312, 2.492; all P<0.05). The expression of ADAR1 protein and 5-serotonin-2c receptor protein in amygdala of social isolation group were significantly lower than those of social isolation group ( t=11.37, 12.65; P<0.01). The expression of ADAR1 protein and 5-serotonin-2c receptor protein in the amygdala of the ADAR1 inducer social isolation group were significantly higher than those of the social isolation group ( t=3.02, 4.401; P<0.05). Conclusion:ADAR1 inducer alleviates the aggressive behavior of social isolated BALB / c mice by enhancing the protein expression of 5-serotonin-2c receptor in the amygdala of social isolated BALB/c mice.

Currently, there is no efficacious pharmacological treatment for traumatic brain injury (TBI). Previous studies revealed that L-lactate preconditioning has shown rich neuroprotective effects against cerebral ischemia, and therefore has the potential to improve neurological outcomes after TBI. L-lactate played a neuroprotective role by activating GPR81 in diseases of the central nervous system (CNS) such as TBI and cerebral ischemia. In this study we investigated the effects of L-lactate preconditioning on TBI and explored the underlying mechanisms. In this study, the mNSS test revealed that L-lactate preconditioning alleviates the neurological deficit caused by TBI in rats. L-lactate preconditioning significantly increased the expression of GPR81, PSD95, GAP43, BDNF, and MCT2 24 h after TBI in the cortex and hippocampus compared with the sham group. Taken together, these data suggested that L-lactate preconditioning is an effective method with which to recover neurological function after TBI. This reveals the mechanism of L-lactate preconditioning on TBI and provides a potential therapeutic method for TBI in humans.

Introduction Social isolation induces depressive-like behavior in animals and humans by impacting RNA editing, but the detailed mechanisms are still unknown. The purpose of this study was to explore how an ADAR1 (RNA-editing enzyme) inducer and inhibitor may impact the isolation-induced depressive-like behavior of mice and to identify new therapeutic targets for the development of an effective solution for the recovery from depressive-like behavior in socially isolated animals and humans. Methods Twenty-one-day-old BALB/c mice with and without isolation treatment were evaluated for depressive-like behavior by open-field tests, tail suspension tests, and forced swimming tests. Immunohistochemistry and Western blots were used to measure the immunoreactivity and protein expression of ADAR1 (p110). In addition, the isolated mice were treated with an ADAR1 inducer (IFN-γ) or inhibitor (EHNA). The performance of both treatments on the behavior of and ADAR1 (p110) expression in isolated mice was examined. Results Both the immunoreactivity and protein expression of ADAR1 (p110) in the prefrontal cortex decreased in isolated BALB/c mice with depressive-like behavior compared to those of the age-matched, gregarious BALB/c mice. Additionally, the treatments with ADAR1 inducer or inhibitor improved or aggravated depressive-like behavior in isolated mice, respectively. Furthermore, the ADAR1 inducer returned the immunoreactivity and protein expression of ADAR1 (p110) back to the normal level. Conclusion The ADAR1 inducer attenuated the effects of social isolation on depressive-like behavior and ADAR1 (p110) in BALB/c mice.