Introduction: Chronic stress exposure is the main environmental factor leading to cognitive impairment, but the detailed molecular mechanism is still unclear. Adenosine Deaminase acting on double-stranded RNA1(ADAR1) is involved in the occurrence of chronic stress-induced cognitive impairment. In addition, dopamine and Adenosine 3'5'-monophosphate-regulated phospho-protein (DARPP-32) gene variation affects cognitive function. Therefore, we hypothesized that ADAR1 plays a key role in chronic stress-induced cognitive impairment by acting on DARPP-32. Methods: In this study, postnatal 21-day-old male BALB/c mice were exposed to chronic unpredictable stressors. After that, the mice were treated with ADAR1 inducer/inhibitor. The cognitive ability and cerebral DARPP-32 protein expression of BALB/c mice were evaluated. In order to explore the link between ADAR1 and DARPP-32, the effects of ADAR1 high/low expression on DARPP-32 protein expression in vitro were detected. Results: ADAR1 inducer alleviates cognitive impairment and recovers decreased DARPP-32 protein expression of the hippocampus and prefrontal cortex in BALB/c mice with chronic unpredictable stress exposure. In vivo and in vitro studies confirm the results predicted by bio-informatics; that is, ADAR1 affects DARPP-32 expression via miR-874-3p. Discussion: The results in this study demonstrate that ADAR1 affects the expression of DARPP-32 via miR-874-3p, which is involved in the molecular mechanism of pathogenesis in chronic unpredictable stress-induced cognitive impairment. The new findings of this study provide a new therapeutic strategy for the prevention and treatment of stress cognitive impairment from epigenetics.

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.

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 enhances the aggressive behavior of animals, but the detailed mechanism remains unclear. Epigenetic studies have suggested that Htr2c RNA editing is closely related to aggressive behavior. This study aims to obtain a fundamental understanding of how social isolation impacts adenosine deaminase acting on RNA 1 (ADAR1, RNA editing enzyme) and Htr2c RNA editing, leading to aggressive behavior, and explore the effective solutions for the recovery of this behavior. Methods:We evaluated 21-day-old BALB/c mice with and without isolation for aggressive behavior using a resident-intruder test. Immune-reactivity and protein expression of ADAR1 (p110) were measured using immunohistochemistry and Western blotting. Htr2c RNA editing was evaluated using pyrosequencing. In addition, the 5-HT 2C R antagonist SB243213/5-HT 2C R inverse agonist SB206553 was used to treat the isolated mice, and the performance of both treatments on the behavior, ADAR1 (p110) expression, and Htr2c RNA editing in isolated mice was examined. Results:Both the protein expression and immune-reactivity of ADAR1 (p110) in the amygdala decreased, but the percentage of Htr2c RNA editing at A and B sites of amygdala only showed a moderate increase in isolated BALB/c mice with enhanced aggressive behavior compared to the age-matched group-housed BALB/c mice. Additionally, treatment with the 5-HT 2C R antagonist SB243213/5-HT 2C R inverse agonist SB206553 recovered the enhanced aggressive behavior of isolated mice and returned the protein expression and immune-reactivity of ADAR1 (p110) back to the normal level. Moreover, compared to the age-matched isolated mice treated with physiological saline, isolated mice treated with 5-HT 2C R inverse agonist SB206553 showed a lower percentage of Htr2c RNA editing at both A and B sites, and the same result occurred in isolated mice treated with 5-HT 2C R antagonist SB243213 at B site of Htr2c RNA editing. Conclusions:The 5-HT 2C R antagonist SB243213/5-HT 2C R inverse agonist SB206553 recovered increased aggressive behavior of isolated BALB/c mice mediated by ADAR1 (p110) expression and Htr2c RNA editing.

Objective To explore the effects of ADAR1 inducer and inhibitor on cognition and ADAR1 expression of isolated BALB/c mice.Methods Sixty healthy BALB/c mice were divided into 6 groups according to randomized design with 10 animals each group,the gregarious control group (GH),social isolation model group (SI),ADAR1 inducer treated gregarious group (GH+IFN-γ),ADAR1 inhibitor treated gregarious group (GH+EHNA),ADAR1 inducer treated isolation group (SI+IFN-γ) and ADAR1 inhibitor treated isolation group (SI+EHNA).Mice in drug treatment groups were treated with ADAR1 inducer (5.0? 104 U/kg,20 ml/kg,ip) and inhibitor (10 mg/kg,20 ml/kg,ip).Objection recognition test was used to measure cognition.Immunohistochenmistry was used to measure ADARI immunoreactivity and Western blotwas used to measure ADAR1 protein expression.Results In the objection recognition test,the non-spatial discrimination index of mice in SI group (-0.16±0.09) was significantly lower than that of GH group (0.41 ±0.17,P＜0.01),the non-spatial discrimination index of mice in SI+IFN-γ group (0.20±0.09) and in SI+ EHNA group (-0.29±0.12) was higher (P＜0.01) and lower (P＜0.05) than that of the SI group respectively.The immunohistochemistry results showed that the ADAR1 immunoreactivity in hippocampus of mice in SI group (Hilus:(0.013±0.003),CAI:(0.021±0.005)) decreased significantly compared to those of GH group(Hilus:(0.021 ±0.002),(0.047±0.004);both P＜0.05).And GH+IFN-γgroup mice showed increased ADAR1 immunoreactivity obviously in Hilus ((0.013±0.003) vs (0.023±0.004),P＜0.01) and in CA1 ((0.021±0.005) vs (0.040±0.005),P＜0.01) compared with that of SI group,ADAR1 inducer recovered the above abnornal ADAR1 immunoreactivity.Western blot results showed that the ADAR1 protein expression of mice in SI group (0.48 ±0.07) in hippocampus was significantly decreased (P＜0.01) compared to that of GH group (1.00 ±0.00).The level of ADAR1 protein in SI+IFN-γgroup(0.82 ±0.04) increased compared with that of SI group.Conclusions Four weeks of social isolation can reduce the non-spatial cognitive ability of BALB/c mice and decrease the expression of ADAR1 in the hippocampus.The ADAR1 inducers and inhibitors can reverse and aggravate the cognitive impairment caused by social isolation respectively.The related mechanisms may be related to the expression of ADAR1.

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.

ObjectiveTo explore the effects of social isolation on the cognition and expression of 5-HT2C receptor(5-HT2CR) and adenosine deaminase that act on RNA 1(ADAR1) in BALB/c mice.MethodsThe healthy BALB/c mice were isolated for 2,4,and 8 weeks individually since postnatal 21 days respectively to set up isolation mice model,the same age mice without isolation were regarded as control group.The new object location and the new object recognition tests were used to measure the spatial and non-spatial cognitive function,and western blot was used to measure the protein expression of 5-HT2CR and ADAR1.ResultsThe new object location test showed that the spatial discrimination index (DI) of BALB/c mice isolated for 2 weeks was decreased significantly compared with the control group(control group was (0.075±0.340),isolation group was (-0.653±0.308),P<0.05),and no obvious difference was found for the group isolated for 4 and 8 weeks.The new object recognition test showed that the non-spatial DI of BALB/c mice isolated for 2 and 4 weeks were decreased significantly compared with the control group(control 2 weeks group was (0.088±0.210),isolation 2 weeks group was (-0.945±0.194),P<0.05;control 4 weeks group was (0.105±0.267),isolation 4 weeks group was (-0.506±0.215),P<0.05),and no obvious difference was found for the group isolated for 8 weeks.Compared with the control group the expression of 5-HT2CR and ADAR1 in the hippocampus were decreased significantly for the group isolated for 2 weeks.(5-HT2CR:control group was (1.025±0.144),isolation group was (0.891±0.026),P<0.05.ADAR1: control group was (0.839±0.120),isolation group was (0.629±0.094),P<0.05).ConclusionsTwo week social isolation results in the decrease of spatial and non-spatial cognitive function in BALB/c mice,in the meanwhile,social isolation stress results in the obvious decrease of 5-HT2C receptor and ADAR1 protein expression in the hippocampus of BALB/c mice.

Objective To explore the effect of depression on loneliness in medical students',and the mediating effects of introverted personality and social support.Methods EPQ,UCLA,SSRS,and POMS questionnaire were used,and surveyed data was collected from Dalian Medical University medical students.Results The scores of depressive mood,introverted personality,social support and loneliness were (17.77±4.45),(11.97±5.21),(34.52±6.15) and (38.02±6.36).Depression was positively related to loneliness and introverted personality (r=0.286,0.508,P＜0.01),and social support was negatively related to loneliness (r =-0.443,P＜0.01).Introverted personality was positively related to loneliness(r=0.401,P＜0.01).The total effect value was 0.670.The mediating effect of introversion as mediator variable was 0.221,accounting for 33％ of the total effect.Social support as intermediary variable,intermediary effect value was 0.449,accounting for 67％ of the total effect.Standard value of mediating effect between depression and introverted personality showed as 0.508 (95％CI=0.475-0.725,P＜0.0i),standard value of mediating effect between depression and social support showed as-0.150 (95％CI=0.989-1.469,P＜0.01),introverted personality was the mediating variant of depression and loneliness,standard value of mediating effect was 0.156 (95％ CI=0.080-0.232,P＜0.01),social support was the mediating variant of depression and loneliness,standard value of mediating effect was 0.317 (95％ CI=0.177-0.457,P＜0.01).Conclusions Introverted personality and social support play an intermediary role between depression and loneliness.