Research progress on the immunomodulatory effects and mechanisms of trace amine-associated receptor 1 / 生理学报

Trace amines are endogenous molecules distributed in the central nervous system and peripheral tissues that resemble common biogenic amines in terms of subcellular localization, chemical structure, and metabolism. Trace amine-associated receptor (TAAR) is a kind of evolutionarily conserved G-protein-coupled receptors in vertebrates, in which TAAR1 is a functional regulator of monoamine transmitters such as dopamine and serotonin. TAAR1 is widely considered as a potential therapeutic target for schizophrenia, depression and drug addiction. Moreover, TAAR1 is also expressed in peripheral tissues. The homeostasis imbalance of trace aminergic system can induce over-activation of peripheral immune system and central immune inflammatory response. TAAR1 modulators are becoming potential emerging drugs for the treatment of immune-related illnesses, because they may play a major role in the activation or modulation of immune response.

The Nucleus Accumbens CRH-CRHR1 System Mediates Early-Life Stress-Induced Sleep Disturbance and Dendritic Atrophy in the Adult Mouse / 神经科学通报·英文版

Adverse experiences in early life have long-lasting negative impacts on behavior and the brain in adulthood, one of which is sleep disturbance. As the corticotropin-releasing hormone (CRH)-corticotropin-releasing hormone receptor 1 (CRHR1) system and nucleus accumbens (NAc) play important roles in both stress responses and sleep-wake regulation, in this study we investigated whether the NAc CRH-CRHR1 system mediates early-life stress-induced abnormalities in sleep-wake behavior in adult mice. Using the limited nesting and bedding material paradigm from postnatal days 2 to 9, we found that early-life stress disrupted sleep-wake behaviors during adulthood, including increased wakefulness and decreased non-rapid eye movement (NREM) sleep time during the dark period and increased rapid eye movement (REM) sleep time during the light period. The stress-induced sleep disturbances were accompanied by dendritic atrophy in the NAc and both were largely reversed by daily systemic administration of the CRHR1 antagonist antalarmin during stress exposure. Importantly, Crh overexpression in the NAc reproduced the effects of early-life stress on sleep-wake behavior and NAc morphology, whereas NAc Crhr1 knockdown reversed these effects (including increased wakefulness and reduced NREM sleep in the dark period and NAc dendritic atrophy). Together, our findings demonstrate the negative influence of early-life stress on sleep architecture and the structural plasticity of the NAc, and highlight the critical role of the NAc CRH-CRHR1 system in modulating these negative outcomes evoked by early-life stress.

Prefrontal Nectin3 Reduction Mediates Adolescent Stress-Induced Deficits of Social Memory, Spatial Working Memory, and Dendritic Structure in Mice / 神经科学通报·英文版

Chronic stress may disrupt the normal neurodevelopmental trajectory of the adolescent brain (especially the prefrontal cortex) and contribute to the pathophysiology of stress-related mental illnesses, but the underlying molecular mechanisms remain unclear. Here, we investigated how synaptic cell adhesion molecules (e.g., nectin3) are involved in the effects of adolescent chronic stress on mouse medial prefrontal cortex (mPFC). Male C57BL/6N mice were subjected to chronic social instability stress from postnatal days 29 to 77. One week later, the mice exposed to chronic stress exhibited impaired social recognition and spatial working memory, simplified dendritic structure, and reduced spine density in the mPFC. Membrane localization of nectin3 was also altered, and was significantly correlated with behavioral performance. Furthermore, knocking down mPFC nectin3 expression by adeno-associated virus in adolescent mice reproduced the stress-induced changes in behavior and mPFC morphology. These results support the hypothesis that nectin3 is a potential mediator of the effects of adolescent chronic stress on prefrontal structural and functional abnormalities.

Early-life stress alters sleep structure and the excitatory-inhibitory balance in the nucleus accumbens in aged mice / 中华医学杂志(英文版)

BACKGROUND@#Exposure to adverse experiences in early life may profoundly reshape the neurodevelopmental trajectories of the brain and lead to long-lasting behavioral and neural alterations. One deleterious effect of early-life stress that manifests in later life is sleep disturbance, but this has not been examined in aged mice and the underlying neural mechanisms remain unknown. Considering the important role of the nucleus accumbens (NAc) in the sleep-wake regulation, this study aimed to assess the effects of early-life stress on the sleep behaviors in aged mice and the potential involvement of the NAc in stress-induced sleep abnormalities.@*METHODS@#Twenty aged male C57BL/6 mice (>16 months, n = 10 per group) were used in this study. During post-natal days 2 to 9, dams were provided with either sufficient (control) or a limited nesting and bedding materials (stressed). When the mice were 16 to 17 months old, their sleep-wake behaviors were recorded over 24 h using electroencephalogram and electromyelogram. The amount of each sleep-wake stage, mean duration, and stage transition was analyzed. Then, five animals were randomly chosen from each group and were used to measure the expression levels of vesicular glutamate transporter-1 (VGluT1) and vesicular transporters of γ-aminobutyric acid (VGAT) in the NAc using immunohistochemistry. Group comparisons were carried out using Student t test or analysis of variances when appropriate.@*RESULTS@#Compared with the control mice, the early-life stressed aged mice spent less time awake over 24 h (697.97 ± 77.47 min vs. 631.33 ± 34.73 min, t17 = 2.376, P = 0.030), accordingly, non-rapid eye movement sleep time was increased (667.37 ± 62.07 min vs. 723.54 ± 39.21 min, t17 = 2.326, P = 0.033) and mean duration of rapid eye movement sleep was prolonged (73.00 ± 8.98 min vs. 89.39 ± 12.69 min, t17 = 3.277, P = 0.004). Meanwhile, we observed decreased VGluT1/VGAT ratios in the NAc in the stressed group (F(1, 16) = 81.04, P < 0.001).@*CONCLUSION@#Early adverse experiences disrupt sleep behaviors in aged mice, which might be associated with the excitatory-inhibitory imbalance in the NAc.

Adolescent stress increases depression-like behaviors and alters the excitatory-inhibitory balance in aged mice / 中华医学杂志(英文版)

BACKGROUND@#Depression affects approximately 5% of elderly people and its etiology might be related to chronic stress exposure during neurodevelopmental periods. In this study, we examined the effects of adolescent chronic social stress in aged mice on depressive behaviors and the excitatory-inhibitory (E/I) balance in stress-sensitive regions of the brain.@*METHODS@#Sixty-four adolescent, male C57BL/6 mice were randomly assigned to either the 7-week (from post-natal days 29 to 77) social instability stress (stress group, n = 32) or normal housing conditions (control group, n = 32). At 15 months of age, 16 mice were randomly selected from each group for a series of behavioral tests, including two depression-related tasks (the sucrose preference test and the tail suspension test). Three days following the last behavioral test, eight mice were randomly selected from each group for immunohistochemical analyses to measure the cell density of parvalbumin (PV)- and calretinin (CR)-positive gamma-aminobutyric-acid (GABA)ergic inhibitory inter-neurons, and the expression levels of vesicular transporters of glutamate-1 (VGluT1) and vesicular GABA transporter (VGAT) in three stress-sensitive regions of the brain (the medial pre-frontal cortex [mPFC], hippocampus, and amygdala).@*RESULTS@#Behaviorally, compared with the control group, adolescent chronic stress increased depression-like behaviors as shown in decreased sucrose preference (54.96 ± 1.97% vs. 43.11 ± 2.85%, t(22) = 3.417, P = 0.003) and reduced latency to immobility in the tail suspension test (92.77 ± 25.08 s vs. 33.14 ± 5.95 s, t(25) = 2.394, P = 0.025), but did not affect anxiety-like behaviors and pre-pulse inhibition. At the neurobiologic level, adolescent stress down-regulated PV, not CR, inter-neuron density in the mPFC (F(1, 39) = 19.30, P  10.09, all P < 0.004), which suggests stress-induced hypoexcitability in these regions.@*CONCLUSIONS@#Chronic stress during adolescence increased depression-like behaviors in aged mice, which may be associated with the E/I imbalance in stress-sensitive brain regions.

Adolescent stress increases depression-like behaviors and alters the excitatory-inhibitory balance in aged mice / 中华医学杂志(英文版)

Background@#Depression affects approximately 5% of elderly people and its etiology might be related to chronic stress exposure during neurodevelopmental periods. In this study, we examined the effects of adolescent chronic social stress in aged mice on depressive behaviors and the excitatory-inhibitory (E/I) balance in stress-sensitive regions of the brain.@*Methods@#Sixty-four adolescent, male C57BL/6 mice were randomly assigned to either the 7-week (from post-natal days 29 to 77) social instability stress (stress group, n = 32) or normal housing conditions (control group, n = 32). At 15 months of age, 16 mice were randomly selected from each group for a series of behavioral tests, including two depression-related tasks (the sucrose preference test and the tail suspension test). Three days following the last behavioral test, eight mice were randomly selected from each group for immunohistochemical analyses to measure the cell density of parvalbumin (PV+)- and calretinin (CR+)-positive gamma-aminobutyric-acid (GABA)ergic inhibitory inter-neurons, and the expression levels of vesicular transporters of glutamate-1 (VGluT1) and vesicular GABA transporter (VGAT) in three stress-sensitive regions of the brain (the medial pre-frontal cortex [mPFC], hippocampus, and amygdala).@*Results@#Behaviorally, compared with the control group, adolescent chronic stress increased depression-like behaviors as shown in decreased sucrose preference (54.96 ± 1.97% vs. 43.11 ± 2.85%, t(22) = 3.417, P = 0.003) and reduced latency to immobility in the tail suspension test (92.77 ± 25.08 s vs. 33.14 ± 5.95 s, t(25) = 2.394, P = 0.025), but did not affect anxiety-like behaviors and pre-pulse inhibition. At the neurobiologic level, adolescent stress down-regulated PV+, not CR+, inter-neuron density in the mPFC (F(1, 39) = 19.30, P < 0.001), and hippocampus (F(1, 42) = 5.823, P = 0.020) and altered the CR+, not PV+, inter-neuron density in the amygdala (F(1, 28) = 23.16, P < 0.001). The VGluT1/VGAT ratio was decreased in all three regions (all F > 10.09, all P < 0.004), which suggests stress-induced hypoexcitability in these regions.@*Conclusions@#Chronic stress during adolescence increased depression-like behaviors in aged mice, which may be associated with the E/I imbalance in stress-sensitive brain regions.

Early-life stress alters sleep structure and the excitatory-inhibitory balance in the nucleus accumbens in aged mice / 中华医学杂志(英文版)

Background@#Exposure to adverse experiences in early life may profoundly reshape the neurodevelopmental trajectories of the brain and lead to long-lasting behavioral and neural alterations. One deleterious effect of early-life stress that manifests in later life is sleep disturbance, but this has not been examined in aged mice and the underlying neural mechanisms remain unknown. Considering the important role of the nucleus accumbens (NAc) in the sleep-wake regulation, this study aimed to assess the effects of early-life stress on the sleep behaviors in aged mice and the potential involvement of the NAc in stress-induced sleep abnormalities.@*Methods@#Twenty aged male C57BL/6 mice (>16 months, n = 10 per group) were used in this study. During post-natal days 2 to 9, dams were provided with either sufficient (control) or a limited nesting and bedding materials (stressed). When the mice were 16 to 17 months old, their sleep-wake behaviors were recorded over 24 h using electroencephalogram and electromyelogram. The amount of each sleep-wake stage, mean duration, and stage transition was analyzed. Then, five animals were randomly chosen from each group and were used to measure the expression levels of vesicular glutamate transporter-1 (VGluT1) and vesicular transporters of γ-aminobutyric acid (VGAT) in the NAc using immunohistochemistry. Group comparisons were carried out using Student t test or analysis of variances when appropriate.@*Results@#Compared with the control mice, the early-life stressed aged mice spent less time awake over 24 h (697.97 ± 77.47 min vs. 631.33 ± 34.73 min, t17 = 2.376, P = 0.030), accordingly, non-rapid eye movement sleep time was increased (667.37 ± 62.07 min vs. 723.54 ± 39.21 min, t17 = 2.326, P = 0.033) and mean duration of rapid eye movement sleep was prolonged (73.00 ± 8.98 min vs. 89.39 ± 12.69 min, t17 = 3.277, P = 0.004). Meanwhile, we observed decreased VGluT1/VGAT ratios in the NAc in the stressed group (F(1, 16) = 81.04, P < 0.001).@*Conclusion@#Early adverse experiences disrupt sleep behaviors in aged mice, which might be associated with the excitatory-inhibitory imbalance in the NAc.

Association between Perceived Stressfulness of Stressful Life Events and the Suicidal Risk in Chinese Patients with Major Depressive Disorder / 中华医学杂志(英文版)

<p><b>Background</b>Patients with major depressive disorder (MDD) usually have high risk of suicidality. Few studies have investigated the effects of stressful life events (SLEs) on the risk of suicide in Chinese patients who have developed MDD. This study aimed to investigate the impact of SLEs on suicidal risk in Chinese patients with MDD.</p><p><b>Methods</b>In total, 1029 patients with MDD were included from nine psychiatric hospitals to evaluate the impact of SLEs on suicidal risk. Patients fulfilling the Mini-International Neuropsychiatric Interview (MINI) criteria for MDD were included in the study. Patients were excluded if they had lifetime or current diagnoses of psychotic disorder, bipolar disorder, and alcohol or substance dependence. Depressive symptoms were assessed by the 17-item Hamilton Depression Scale (HAMD-17). The suicidal risk of MDD patients was determined by the suicide risk module of MINI. SLEs were assessed by the Life Events Scale.</p><p><b>Results</b>No gender difference was found for suicidal risk in MDD patients. Patients with suicidal risk had younger ages, lower education levels, more drinking behavior, and lower marriage rate, and fewer people had child and more severe depressive symptoms than nonsuicidal risk group. High-level perceived stressfulness (HPS) and number of SLEs that patients were exposed to were significantly greater in patients with suicidal risk than patients without. In multivariate logistic analysis, HPS of SLEs (odds ratio [OR] = 1.54, 95% confidence interval [CI]: 1.16-2.05, P = 0.003) and depressive symptoms (OR = 1.08, 95% CI: 1.05-1.11, P < 0.001) were associated with suicidal risk even after adjustment of gender, age, marriage, drinking behavior, and childless.</p><p><b>Conclusions</b>HPS of SLEs is associated with suicide risk in Chinese patients with MDD. Further suicide prevention programs targeting this risk factor are needed.</p><p><b>Trial Registration</b>ClinicalTrials.gov: NCT02023567; https://clinicaltrials.gov/ct2/show/NCT02023567?term=NCT02023567&rank=1.</p>

Is early-onset in major depression a predictor of specific clinical features with more impaired social function? / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Early-onset major depressive disorder (MDD) (EOD) is often particularly malignant due to its special clinical features, accompanying impaired social function, protracted recovery time, and frequent recurrence. This study aimed to observe the effects of age onset on clinical characteristics and social function in MDD patients in Asia.</p><p><b>METHODS</b>In total, 547 out-patients aged 18-65 years who were from 13 study sites in five Asian countries were included. These patients had MDD diagnose according to the Diagnostic and Statistical Manual of Mental Disorders, 4 th Edition criteria. Clinical features and social function were assessed using Symptom Checklist-90-revised (SCL-90-R) and Sheehan Disability Scale (SDS). Quality of life was assessed by a 36-item Short-form Health Survey (SF-36). Analyses were performed using a continuous or dichotomous (cut-off: 30 years) age-of-onset indicator.</p><p><b>RESULTS</b>Early-onset MDD (EOD, <30 years) was associated with longer illness (P = 0.003), unmarried status (P < 0.001), higher neuroticism (P ≤ 0.002) based on the SCL-90-R, and more limited social function and mental health (P = 0.006, P = 0.007) based on the SF-36 and SDS. The impairment of social function and clinical severity were more prominent at in-patients with younger onset ages. Special clinical features and more impaired social function and quality of life were associated with EOD, as in western studies.</p><p><b>CONCLUSIONS</b>EOD often follows higher levels of neuroticism. Age of onset of MDD may be a predictor of clinical features and impaired social function, allowing earlier diagnosis and treatment.</p>

Antipsychotic Medications in Major Depression and the Association with Treatment Satisfaction and Quality of Life: Findings of Three National Surveys on Use of Psychotropics in China Between 2002 and 2012 / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Optimizing treatment outcomes for depression requires understanding of how evidence-based treatments are utilized in clinical practice. Antipsychotic medications concurrent with antidepressant treatment are frequently used in major depression, but few studies have investigated trends and patterns of their use over time. This study aimed to examine the prescription patterns of antipsychotic medications for major depression in China from 2002 to 2012 and their association with treatment satisfaction and quality of life (QOL).</p><p><b>METHODS</b>A total of 3655 subjects with major depression treated in 45 Chinese psychiatric hospitals/centers nationwide were interviewed between 2002 and 2012. Patients' socio-demographic and clinical characteristics including psychopathology, medication side effects, satisfaction with treatment and QOL were recorded using a standardized protocol and data collection.</p><p><b>RESULTS</b>The frequency of antipsychotic use was 24.9% in the whole sample; the corresponding figures were 17.1%, 20.3%, and 32.8% in 2002, 2006, and 2012, respectively (χ2 = 90.3, df = 2, P < 0.001). Multiple logistic regression analyses revealed that patients on concurrent antipsychotics had significantly more delusions or hallucinations, longer illness duration, greater side effects, and more likely to be treated as inpatients and in major hospitals (i.e., Level-III hospital). Antipsychotic use was associated with lower treatment satisfaction while there was no significant difference with respect to physical and mental QOL between the antipsychotic and nonantipsychotic groups.</p><p><b>CONCLUSIONS</b>Concurrent antipsychotic use was found in about one in four treated depressed patients in China, which has increased over a 10-year period. Considering the association of drug-induced side effects and the lack of patients' and relatives' satisfaction with antipsychotic treatment, further examination of the rationale and appropriateness of the use of antipsychotics in depression is needed.</p>